Radiology Review Manual (Dahnert, Radiology Review Manual)

Authors: Dahnert, Wolfgang

Title: Radiology Review Manual, 6th Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Ear Nose and Throat

Ear Nose and Throat

Differential Diagnosis of Ear, Nose, and Throat Disorders

Facial nerve paralysis

• INTRACRANIAL SEGMENT

  • intraaxial

    • brainstem glioma, metastasis, multiple sclerosis, cerebrovascular accident, hemorrhage

      • cranial nerve VI also involved

  • extraaxial

    • CPA tumor (acoustic neuroma, meningioma, epidermoid), CPA inflammation (sarcoidosis, basilar meningitis), vertebrobasilar dolichoectasia, AVM, aneurysm

      • cranial nerve VIII also involved

• intratemporal SEGMENT

  • fracture, cholesteatoma, paraganglioma, hemangioma, facial nerve schwannoma, metastasis, Bell palsy, otitis media

    • loss of lacrimation, hyperacusis, loss of taste

• EXTRACRANIAL PAROTID SEGMENT

  • forceps delivery, penetrating facial trauma, parotid surgery, parotid malignancy, malignant otitis externa

    • preservation of lacrimation, stapedius reflex, taste

Ear

Hearing deficit

• CONDUCTIVE HEARING LOSS

  • decrease in air conduction via EAC, tympanic membrane, ossicular chain, oval window (sound via headphones)

    • normal bone conduction (sound via bone oscillator)

  • trauma: incudostapedial / malleoincudal subluxation; incus dislocation; stapes dislocation; stapes / malleus fracture

  • destruction of ossicular chain: otitis media

  • restriction of ossicular chain: fenestral otosclerosis

  • CT is the modality of choice!

• SENSORINEURAL HEARING LOSS (most common)

  • elevated conduction thresholds for bone + air

• sensory / cochlear SNHL = damage to cochlea / organ of Corti (less common)

  • bony labyrinth

    • demineralization: otosclerosis (otospongiosis), osteogenesis imperfecta, Paget disease, syphilis

    • congenital deformity: cochlear dys- / aplasia, Michel anomaly, Mondini dysplasia, enlarged vestibular aqueduct syndrome, X-linked sensorineural hearing loss

    • traumatic lesion: transverse fracture, perilymphatic fistula, cochlear concussion

    • destructive lesion: inflammatory lesion, neoplastic lesion

  • CT is the modality of choice!

• membranous labyrinth

  • enhancement: labyrinthitis, Cogan syndrome (early phase of autoimmune interstitial keratitis), intralabyrinthine schwannoma, site of postinflammatory perilymphatic fistula

  • obliteration: labyrinthitis ossificans, Cogan syndrome (late phase)

  • hemorrhage: trauma, labyrinthitis, coagulopathy, tumor fistulization

  • M ni re disease (vertigo + fluctuating sensory sensorineural hearing loss)

  • MRI is the modality of choice!

• neural / retrocochlear SNHL (more common)

  • = abnormalities of neurons of spiral ganglion + central auditory pathways

  • IAC / cerebellopontine angle

    • neoplastic lesions: vestibular / trigeminal schwannoma (acoustic neuroma in 1%), meningioma, arachnoid cyst, epidermoid cyst, leptomeningeal carcinomatosis, lymphoma, lipoma, hemangioma

    • nonneoplastic lesion: sarcoidosis, meningitis, vascular loop, siderosis

  • intraaxial auditory pathway

    (brainstem, thalamus, temporal lobe)

    • ischemic lesion

    • neoplastic lesion

    • traumatic lesion

    • demyelinating lesion

  • MRI is the modality of choice!

Pulsatile tinnitus Vascular Tympanic Membrane

• = perception of a rhythmic cardiac synchronous sound of ringing / buzzing / roaring

• No abnormality (20%)

• Congenital vascular variants (21%)

  • Aberrant ICA

    • = result of anastomosis of enlarged inferior tympanic artery with enlarged caroticotympanic artery when cervical ICA is underdeveloped

  • Dehiscent jugular bulb

  • High-riding nondehiscent jugular bulb (= jugular megabulb)

    • high jugular bulb with diverticulum projecting cephalad into petrous temporal bone

• Acquired vascular lesions (25%)

  • Dural AVM

  • Extracranial arteriovenous fistula

  • High-grade stenotic vascular lesion: carotid artery atherosclerosis, fibromuscular dysplasia, carotid artery dissection

  • Aneurysm involving horizontal segment of petrous ICA

• Temporal bone tumors (31%)

  • Paraganglioma (27%): glomus tympanicum, glomus jugulare

  • Meningioma

  • Hemangioma

P.356

• Miscellaneous

  • Cholesterol granuloma

Demineralization of Temporal Bone

• Otosclerosis = otospongiosis

• Paget disease = osteoporosis circumscripta

  • sensorineural / mixed hearing loss (cochlear involvement / stapes fixation in oval window)

  • usually lytic changes beginning in petrous pyramid + progressing laterally; otic capsule last to be affected

  • calvarial changes basilar impression

• Fibrous dysplasia

  • monostotic with temporal bone involvement

  • painless mastoid swelling

  • conductive hearing loss (from narrowing of EAC / middle ear)

  • homogeneously dense thickened bone (fibro-osseous tissue less dense than calvarial bone)

  • expanded bone with preserved cortex

  • lytic lesions (less frequent)

  • sparing of membranous labyrinth, facial nerve canal, IAC is the rule

• Osteogenesis imperfecta

  • changes similar to otosclerosis

  • van der Hoeve-de Kleyn syndrome

    • = osteogenesis imperfecta + hearing loss + blue sclerae in patients in late 2nd / early 3rd decade

• Otosyphilis: labyrinthitis + gummatous lesion of internal auditory canal + inflammatory resorptive osteitis

  • moth-eaten permeative osteolysis of temporal bone

• Metastasis

External Ear Masses

• CONGENITAL

  • Atresia

• INFLAMMATORY

  • Malignant external otitis

  • Keratosis obturans

    • bilateral process in association with chronic sinusitis + bronchiectasis

    • Age: <40 years

  • Cholesteatoma

• BENIGN TUMOR

  • Exostosis = surfer's ear

    • Cause: irritation by cold water

    • bony mass projecting into EAC; often multiple + bilateral

  • Osteoma

    • may invade adjacent bone

    • single in EAC / mastoid

  • Ceruminoma

    • from apocrine + sebaceous glands; bone erosion mimics malignancy

• MALIGNANT TUMOR

  • Squamous cell carcinoma

    • often long history of chronic suppurative otitis media = malignant otitis

  • Basal cell carcinoma

  • Melanoma, adenocarcinoma, adenoid cystic carcinoma

  • Metastases

    • hematogenous: breast, prostate, lung, kidney, thyroid

    • direct spread: skin, parotid, nasopharynx, brain, meninges

    • systemic: leukemia, lymphoma, myeloma

  • Histiocytosis X: in 15% of patients

Middle Ear Masses

• CONGENITAL

  • Aberrant internal carotid artery

    • vascular tympanic membrane

    • pulsatile tinnitus

    • tubular soft-tissue density entering middle ear cavity posterolateral to cochlea, crossing mesotympanum along cochlear promontory, exiting anteromedial to become horizontal portion of carotid canal

    • protrusion into middle ear without bony margin

  • Dehiscent jugular bulb

• INFLAMMATORY

  • Cholesteatoma

  • Cholesterol granuloma

  • Granulation tissue

    • linear strands partially opacifying middle ear cavity without bony erosion

• BENIGN TUMOR

  • Adenomatous tumor (mixed pattern type)

    • intense enhancement

    • no osseous destruction

  • Glomus tumor (multiple in 10%; 8% malignant)

    • Glomus tympanicum: at cochlear promontory

      • seldom erodes bone

    • Glomus jugulare: at jugular foramen

      • invasion of middle ear from below

      • destruction of bony roof of jugular fossa + bony spur separating vein from carotid artery

  • Facial nerve schwannoma

    • persistent Bell palsy (in 5% caused by neurinoma)

    • Location: intracanalicular > IAC

    • tubular mass in enlarged / scalloped facial canal

  • Ossifying hemangioma

  • Choristoma = ectopic mature salivary tissue

  • Endolymphatic sac tumor

    • arises from region of vestibular aqueduct

  • Meningioma

• MALIGNANT TUMOR

  • Squamous cell carcinoma

  • Metastasis

  • Rhabdomyosarcoma

    • Location: orbit > nasopharynx > ear

  • Adenocarcinoma (rare), adenoid cystic carcinoma

Mass on Promontory

• [promontory = bone over basal turn of cochlea]

• Glomus tympanicum

• Congenital cholesteatoma

• Aberrant carotid artery

• Persistent stapedial artery

P.357

Inner Ear Masses

• CONGENITAL

  • Congenital / primary cholesteatoma = epidermoid tumor (3rd most common CPA tumor)

• INFLAMMATION

  • Cholesterol granuloma

  • Petrous apex mucocele

• TUMOR

  • Glomus jugulare tumor

  • Hemangioma, fibro-osseous lesion

  • Metastasis

  • Facial nerve neurinoma

  • Large CPA tumors: acoustic neuroma, meningioma (2nd most common CPA tumor)

Sinuses

Opacification of Maxillary Sinus

• WITHOUT BONE DESTRUCTION

  • Sinus aplasia / hypoplasia

    • Age: NOT routinely visualized at birth, by age 6 antral floor at level of middle turbinate, by age 15 of adult size

    • Location: uni- / bilateral

    • depression of orbital floor with enlargement of orbit

    • lateral displacement of lateral wall of nasal fossa with large turbinate

  • Maxillary dentigerous cyst usually containing a tooth / crown; without tooth = primordial dentigerous cyst

  • Ameloblastoma

  • Acute sinusitis

    • air-fluid level

• WITH BONE DESTRUCTION

  • Maxillary sinus tumor

  • Infection: aspergillosis, mucormycosis, TB, syphilis

  • Wegener granulomatosis; lethal midline granuloma

  • Blowout fracture

Paranasal Sinus Masses

• Mucocele

  • Cause: obstruction of a paranasal sinus

  • bone remodeling / sinus expansion

• Mucus retention cyst

  • Cause: obstruction of small seromucinous gland

  • Location: commonly in floor of maxilla

  • smoothly marginated soft-tissue mass

• Sinonasal polyp

• Antrochoanal polyp

• Inverting papilloma

• Sinusitis

• Carcinoma

Granulomatous Lesions of Sinuses

• Chronic irritants

  • Beryllium

  • Chromate salts

• Infection

  • Tuberculosis

  • Actinomycosis

  • Rhinoscleroma

  • Yaws

  • Blastomycosis

  • Leprosy

  • Rhinosporidiosis

  • Syphilis

  • Leishmaniosis

  • Glanders

• Autoimmune disease

  • Wegener granulomatosis

• Lymphoma-like lesions

  • Midline granuloma

• Unclassified

  • Sarcoidosis

Hyperdense Sinus Secretions

• Inspissated secretions

• Fungal sinusitis

• Hemorrhage into sinus

• Chronic sinusitis infected with bacteria (in particular in very long-standing disease / cystic fibrosis)

Opacified Sinus & Expansion / Destruction

• Plasmacytoma

• Lymphoma

• Unknown etiology: Wegener granulomatosis

• Mucocele

• Polyp

• Fibrous dysplasia, Fibroma (ossifying)

• Aneurysmal bone cyst, Angiofibroma

• Cancer

• Inverting papilloma

• Esthesioneuroblastoma

• Sarcoma: ie, rhabdomyosarcoma

Nose

Nasal Vault Masses

• BENIGN

  • Sinonasal polyp

  • Inverted papilloma

  • Hemangioma

    • history of epistaxis

  • Pyogenic granuloma

    • pedunculated lobular mass

  • Granuloma gravidarum = nasal hemangioma of pregnancy

  • Hemangiopericytoma

  • Juvenile nasopharyngeal angiofibroma

    • arises in superior nasopharynx with extension into nose via posterior choana

• MALIGNANT

  • Lymphoma

  • Melanoma

  • Vascular metastasis

Mass in Nasopharynx

• Nasopharyngeal carcinoma

• Angiofibroma (juvenile)

P.358

• Spine / skull fracture

• Adenoids

• Lymphoma

• Polyp

• Infection

• Plasmacytoma

• Extension of neoplasm (sphenoid / ethmoid sinus ca.)

Congenital Midline Nasal Mass

• = result of faulty regression of embryologic dural diverticulum through foramen cecum + fonticulus frontalis (= nasofrontal fontanel) from the prenasal space

  Frequency:

  1:20,000 to 1:40,000 births

• Dermoid cyst

• Epidermoid cyst

• Nasal glioma = nasal cerebral heterotopia

• Nasal encephalocele

• Hemangioma / lymphangioma

• Dacryocystocele

• Dacryocystitis

Pharynx

Parapharyngeal Space Mass

• BENIGN

  • Asymmetric pterygoid venous plexus

    • racemose, enhancing area along medial border of lateral pterygoid muscle

  • Abscess

    Origin:

    pharyngitis (most common), dental infection, parotid calculus disease, penetrating trauma

  • Atypical second branchial cleft cyst

    Age:	child / young adult

  • protruding parotid gland

  • bulging posterolateral pharyngeal wall

  • cystic mass projecting from deep margin of faucial tonsil toward skull base

• Pleomorphic adenoma of ectopic salivary tissue / of deep lobe of parotid gland (common)

• Schwannoma, neurofibroma

  • Origin:

    usually from cranial nerve X

  • carotid artery pushed anteriorly

• Paraganglioma

  • posterior to carotid artery

  • extremely vascular (numerous flow voids)

  • Lipoma

• MALIGNANT

  • Squamous cell carcinoma

    • direct extension from pharyngeal mucosal space

    • vertical extension to skull base / hyoid bone

  • Salivary gland malignancy

Pharyngeal Mucosal Space Mass

• Asymmetric fossa of Rosenm ller = lateral pharyngeal recess = asymmetry in amount of lymphoid tissue

• Tonsillar abscess

  • sore throat, fever, painful swallowing

• Postinflammatory retention cyst

  • 1 2-cm well-circumscribed cystic mass

• Postinflammatory calcification

  • remote history of severe pharyngitis

  • multiple clumps of calcification

• Benign mixed tumor

  • pedunculated mass arising from minor salivary glands

  • oval / round well-circumscribed mass protruding into airway

• Squamous cell carcinoma

  • infiltrating mass with epicenter medial to + invading parapharyngeal space

  • middle-ear fluid (eustachian tube malfunction)

  • cervical adenopathy

• Non-Hodgkin lymphoma

• Minor salivary gland malignancy

• Thornwaldt cyst

  • Most common congenital head and neck cyst in a child!

Masticator Space Mass

• BENIGN

  • Asymmetric accessory parotid gland

    • Incidence:	21% of general population
      Location:	usually on surface of masseter muscle

    • prominent salivary gland tissue

  • Benign masseteric hypertrophy

    • Cause: bruxism (= nocturnal gnashing of teeth)

    • homogeneous enlargement of one / both masseters

  • Odontogenic abscess / mandibular cysts

    • bad dentition + trismus

  • Lymphangioma, hemangioma

• MALIGNANT

  • Sarcoma (chondro-, osteo-, soft-tissue sarcoma, especially rhabdomyosarcoma in children)

    • infiltrating mass with mandibular destruction

  • Malignant schwannoma

    • tubular mass along cranial nerve V₃

  • Non-Hodgkin lymphoma

  • Infiltrating squamous cell carcinoma

    • extending from pharyngeal mucosa

  • Salivary gland malignancy (mucoepidermoid carcinoma, adenoid cystic carcinoma)

    • extending from parotid gland

  • N.B.: (1) check course of V₃ to foramen ovale for skull base extension to Meckel cave area + cavernous sinus

    • check for extension to pterygopalatine fossa to infraorbital fissure into orbit

Carotid Space Mass

• VASCULAR LESION

  • Ectatic common / internal carotid artery

  • Carotid artery aneurysm / pseudoaneurysm

  • Asymmetric internal jugular vein

  • Jugular vein thrombosis

• BENIGN TUMOR

  • Paraganglioma (carotid body tumor + glomus jugulare + glomus vagale)

  P.359

  • Schwannoma

    • displacement of carotid artery anteromedially + internal jugular vein posteriorly

    • well-encapsulated mass

  • Neurofibroma of cranial nerves IX, X, XI

  • Branchial cleft cyst

• MALIGNANT TUMOR

  • Nodal metastasis from squamous cell carcinoma to interior jugular chain (common)

    • encasement of carotid artery = inoperable

  • Non-Hodgkin lymphoma

Retropharyngeal Space Mass

• INFECTION

  • Reactive lymphadenopathy

    • nodes >10 mm in diameter

  • Abscess:

    • bow-tie shape

  • BENIGN TUMOR

    • Hemangioma

    • Lipoma

  • MALIGNANT TUMOR

    • Metastasis to retropharyngeal nodes

      • from nasopharyngeal squamous cell carcinoma, melanoma, thyroid carcinoma

      • N.B.: sentinel node of Rouviere (= lateral retropharyngeal node) is an early sign of nasopharyngeal cancer before primary mass becomes obvious

    • Non-Hodgkin lymphoma

    • Direct invasion by squamous cell carcinoma

Prevertebral Space Mass

• PSEUDOTUMOR

  • Anterior disk herniation

  • Vertebral body osteophyte

• INFLAMMATION

  • Vertebral body osteomyelitis

  • Abscess

    • extension from retropharyngeal space / osteomyelitis / diskitis / epidural abscess

  • TUMOR

    • Chordoma

    • Vertebral body metastasis: lung, breast, prostate, non-Hodgkin lymphoma, myeloma

      • Metastases to prevertebral space = inoperable

Larynx

Vocal Cord Paralysis

• Birth injury

• Arnold-Chiari malformation

• Intracranial tumor

• Mediastinal mass / cyst

• Vascular ring

• Thyroidectomy

• Malignancy

• fixed vocal cords (fluoroscopy)

Epiglottic Enlargement

• NORMAL VARIANT

  • Prominent normal epiglottis

  • Omega epiglottis

• INFLAMMATION

  • Acute / chronic epiglottitis

  • Angioneurotic edema

  • Stevens-Johnson syndrome

  • Caustic ingestion

  • Radiation therapy

• MASSES

  • Epiglottic cyst

  • Aryepiglottic cyst

  • Foreign body

Aryepiglottic Cyst

• Retention cyst

• Lymphangioma

• Cystic hygroma

• Thyroglossal cyst

• may be symptomatic at birth

• well-defined mass in aryepiglottic fold

Laryngeal Neoplasms

• SQUAMOUS CELL CARCINOMA (95 98%)

  • endoscopically visible due to mucosal involvement

• NON-SQUAMOUS CELL NEOPLASMS (2 5%)

  • malignant:benign = 1:1

  • vasoformative tumor____________33%

    • Benign

      • Hemangioma

      • Lymphangioma

      • Angiofibroma

      • Angiomatosis

      • Granuloma pyogenicum

      • Arteriovenous fistula

      • Phlebectasia, telangiectasia

    • Malignant

      • Angiosarcoma (Kaposi sarcoma)

        • Location: epiglottis (most frequent)

        • intensely enhancing mass

      • Hemangiopericytoma

    • chondrogenic tumor___________________20%

      • Chondroma

      • Chondrosarcoma

      • Osteosarcoma

    • hematopoietic tumor__________________12%

      • Hodgkin / non-Hodgkin lymphoma / leukemia

      • Plasmacytoma

      • Pseudolymphoma

    • salivary gland tumor__________________10%

      • Pleomorphic adenoma

      • Adenoid cystic carcinoma

      • Mucoepidermoid carcinoma

      • Adenocarcinoma

    • fatty-tissue tumor__________________7%

      • Lipoma

      • Liposarcoma

    P.360

    • metastasis__________________7%

      • skin (melanoma) > kidney > breast > lung > prostate > colon > stomach > ovary

    • neurogenic tumor__________________5%

    • myogenic tumor__________________2%

    • fibrohistiocytic tumor__________________2%

Airways

Inspiratory Stridor in Children

• Croup

• Congenital subglottic stenosis

• Subglottic hemangioma

• Airway foreign body

• Esophageal foreign body

• Epiglottitis

Airway Obstruction in Children

Nasopharyngeal Narrowing

• (a) Congenital:	Choanal atresia, choanal stenosis, encephalocele
  (b) Inflammatory:	Adenoidal enlargement, polyps
  (c) Neoplastic:	Juvenile angiofibroma, rhabdomyosarcoma, teratoma, neuroblastoma, lymphoepithelioma
  (d) Traumatic:	Foreign body, hematoma, rhinolith

Oropharyngeal Narrowing

• (a) Congenital:	Glossoptosis + micrognathia (Pierre Robin, Goldenhar, Treacher Collins syndrome), macroglossia (cretinism, Beckwith-Wiedemann syndrome)
  (b) Inflammatory:	Abscess, tonsillar hypertrophy
  (c) Neoplastic:	Lingular tumor / cyst
  (d) Traumatic:	Hematoma, foreign body

Retropharyngeal Narrowing

• = potential space (normally <3/4 of AP diameter of adjacent cervical spine in infants / <3 mm in older children)

  (a) Congenital:	Branchial cleft cyst, ectopic thyroid
  (b) Inflammatory:	Retropharyngeal abscess
  (c) Neoplastic:	Cystic hygroma (originating in posterior cervical triangle with extension toward midline + into mediastinum), neuroblastoma, neurofibromatosis, hemangioma
  (d) Traumatic:	Hematoma, foreign body
  (e) Metabolic:	Hypothyroidism

Vallecular Narrowing

• = valleys on each side of glossoepiglottic folds between base of tongue + epiglottis

  (a) Congenital:	Congenital cyst, ectopic thyroid, thyroglossal cyst
  (b) Inflammatory:	Abscess
  (c) Neoplastic:	Teratoma
  (d) Traumatic:	Foreign body, hematoma

Supraglottic Narrowing

• = area between epiglottis and true vocal cords

  (a) Congenital:	Aryepiglottic fold cyst
  (b) Inflammatory:	Acute bacterial epiglottitis, angioneurotic edema
  (c) Neoplastic:	Retention cyst, cystic hygroma, neurofibroma
  (d) Traumatic:	Foreign body, hematoma, radiation, caustic ingestion
  (e) Idiopathic:	Laryngomalacia

Glottic Narrowing

• = area of true vocal cords

  (a) Congenital:	Laryngeal atresia, laryngeal stenosis, laryngeal web (anterior commissure)
  (b) Neoplastic:	Laryngeal papillomatosis
  (c) Neurogenic:	Vocal cord paralysis (most common)
  (d) Traumatic:	Foreign body, hematoma

Subglottic Narrowing

= short segment between undersurface of true vocal cords + inferior margin of cricoid cartilage is the narrowest portion of child's airway

Neck

Solid Neck Mass

Solid Neck Mass In Neonate

• Cystic hygroma

• Hemangioma

• Neuroblastoma

• Teratoma

• Fibromatosis colli

Solid Neck Mass in Childhood

• Lymphadenopathy

• Fibromatosis colli

• Aggressive fibromatosis

• Malignancy: neuroblastoma (most common), lymphoma, embryonal rhabdomyosarcoma

• Teratoma

• Hemangioma

• Cervicothoracic lipoblastomatosis

• Lipoma

• Thyroid mass / lingual thyroid

• Parathyroid adenoma

• Ectopic thymus

Lymph node enlargement of neck

• NORMAL LYMPH NODES

  • few small oval hypoechoic

  • central linear echogenicity (= invaginating hilar fat)

  • larger in transverse than anteroposterior dimension

P.361

• CERVICAL ADENITIS

  • Location:  posterior cervical triangle

  • Tuberculous adenitis

    • multichambered centrally hypoattenuating mass

    • thick enhancing rim

    • peripheral calcifications

  • MALIGNANT LYMPH NODES

    • increased anteroposterior diameter

    • prominent calcifications suggestive of medullary thyroid cancer

    • axial diameter of >15 in jugulodigastric region / >11 mm elsewhere (in squamous cell carcinoma)

    • CT:

      • marginal enhancement

      • central necrosis (regardless of size)

      • fuzzy borders as sign of extracapsular extension

Low-density Nodes with Peripheral Enhancement

• Tuberculosis

• Metastatic malignancy

• Lymphoma

• Inflammatory conditions

Lymph Node Metastasis by Location

• @ supraclavicular

  • head & neck, lung, breast, esophagus

• @ INTERNAL JUGULAR

  • supraglottic larynx, esophagus, thyroid

• @ midjugular

  • tongue, pharynx, supraglottic larynx

• @ JUGULODIGASTRIC

  • nasopharynx, oropharynx, tonsils, parotid gland, supraglottic larynx

• @ SUBMANDIBULAR

  • skin, submandibular gland, base of tongue

• @ POSTERIOR TRIANGLE

  • nasopharynx, base of tongue

• @ LATERAL PHARYNGEAL

  • nasopharynx, oropharynx

Congenital Cystic Lesions of Neck

• Thyroglossal duct cyst

  • Location:  anterior cervical triangle close to midline between foramen cecum + thyroid isthmus

• Lymphangioma / cystic hygroma

  • Location:  mostly in posterior cervical triangle, occasionally in floor of mouth / tongue

• Branchial cleft anomalies

  • often noted during upper respiratory infection

  • 2nd branchial cleft cyst

    • Location:  near angle of mandible anterior to sternocleidomastoid muscle

  • branchial cleft fistula

    • Location:  apex of piriform sinus to thyroid

  • Cervical dermoid / epidermoid cyst

    • Location:  floor of mouth

  • Cervical thymic cyst

  • Parathyroid cyst

    • Age:  30 50 years

    • hormonally inactive

    • noncolloidal cyst near lower pole of thyroid gland

  • Cervical bronchogenic cyst

    Cause:	anomalous foregut development
    Histo:	columnar ciliated pseudostratified epithelial lining

  • M:F = 3:1

  • draining sinus in suprasternal notch / supraclavicular area

  • cyst up to 6 cm in diameter

  • indentation of trachea

• Laryngocele

Air-containing Masses of Neck

• Laryngocele

• Tracheal diverticulum arising from anterior wall of trachea close to thyroid

• Zenker diverticulum

• Lateral pharyngeal diverticulum located in tonsillar fossa / vallecula / pyriform fossa

Fat-containing Masses of Neck

• Dermoid cyst

• Lipoblastoma

• Liposarcoma (extremely rare <10 years of age)

Salivary glands

Parotid Gland Enlargement

• LOCALIZED INFLAMMATION / INFECTION

  • Chronic recurrent sialadenitis

  • Sialosis

  • Sarcoidosis

  • Tuberculosis

  • Cat-scratch fever

  • Syphilis

  • Parotid abscess secondary to acute bacterial (suppurative) sialadenitis

  • Reactive adenopathy

  • Parotitis: mumps (most common parotid disease in children), HIV

• SYSTEMIC AUTOIMMUNE RELATED DISEASE

  • Sj gren disease (= myoepithelial sialadenitis)

  • Mikulicz disease

• NEOPLASM

  • Frequency: 90 95% occur in parotid gland, 5% in submandibular + sublingual glands; only 1% of all pediatric tumors!

  • benign tumor

    • Pleomorphic / monomorphic adenoma

    • Cystadenolymphoma (= Warthin tumor)

    • Benign lymphoepithelial cysts (AIDS)

    • Lipoma

    • Facial nerve neurofibroma

    • Oncocytoma

    • Parotid hemangioma

    • Angiolipoma

  • primary malignant tumor

    • Mucoepidermoid carcinoma

    • Adenoid cystic carcinoma (= cylindroma)

    • Malignant mixed tumor

    • Adenocarcinoma

    P.362

    • Acinus cell carcinoma

    • Rhabdomyosarcoma

  • metastatic tumor

    • Parotid gland undergoes late encapsulation, which leads to incorporation of lymph nodes!

    • Squamous cell carcinoma

    • Melanoma of periauricular region

    • Non-Hodgkin lymphoma

    • Thyroid carcinoma

• LYMPHOPROLIFERATIVE DISORDER

  • Lymphoma / leukemia

  • Primary non-Hodgkin lymphoma (MALToma)

• CONGENITAL

  • First branchial cleft cyst

Multiple Lesions of Parotid Gland

• Warthin tumor

• Metastases to lymph nodes: squamous cell carcinoma of skin, malignant melanoma, non-Hodgkin lymphoma

• Benign lymphoepithelial cysts (AIDS)

Thyroid

Congenital Dyshormonogenesis

• Trapping defect

  • = defective cellular uptake of iodine into thyroid, salivary glands, gastric mucosa;

  • High doses of inorganic iodine facilitate diffusion into thyroid permitting a normal rate of thyroid hormone synthesis

  • Normal ratio of iodine concentrations for gastric juice:plasma = 20:1

  • nearly entire dose of administered radioiodine is excreted within 24 hours

• Organification defect

  • = deficient peroxidase activity, which catalyzes the oxidation of iodide by H₂O₂ to form monoiodotyrosine (MIT) / diiodotyrosine (DIT)

  • high serum TSH

  • low serum T₄

  • diffuse symmetric thyromegaly

  • high thyroidal uptake of radioiodine / pertechnetate

  • rapid I-131 turnover

  • positive perchlorate washout test

  • Pendred syndrome = autosomal recessive trait of deficient peroxidase regeneration characterized by hypothyroidism + goiter + nerve deafness

• Deiodinase (dehalogenase) defect

  • = deficient deiodination of MIT / DIT to release iodide, which is reutilized to synthesize thyroid hormone production

  • hypothyroidism

  • identification of MIT + DIT in serum + urine following administration of I-131

  • intrinsic iodine deficiency goiter

  • high thyroidal I-131 uptake

  • rapid intrathyroidal turnover of I-131

• Thyroxin-binding globulin (TBG) deficiency

  • abnormal T₄ transport

  • low bound serum T₄ concentration

  • euthyroid

• End-organ resistance to thyroid hormone

  • high serum T₄

  • euthyroid / hypothyroid

  • growth retardation

  • goiter

  • stippled epiphyses

Thyrotoxicosis

• = clinical syndrome of increased systemic metabolism

• Cause:

  • increased thyroid function

    • Graves disease

      • gland may be normal in size in early stage

    • Marine-Lenhart syndrome = nodular Graves = Graves disease coexistent with multinodular goiter

    • Toxic autonomous nodule

    • Toxic multinodular goiter

  • thyroid inflammation

    • Subacute thyroiditis

    • Silent thyroiditis

    • Postpartum thyroiditis

  • iodine-induced hyperthyroidism

  • hyperthyroidism of extrathyroidal origin

    • Factitious hyperthyroidism

    • Ectopic thyroid hormone production:metastatic thyroid cancer, toxic struma ovarii

    • Thyrotropin-induced hyperthyroidism (pituitary adenoma)

• elevated free T4, elevated free T3, or both

Hyperthyroidism

• = overactivity of thyroid due to excess thyroid hormone

• tachycardia, weight loss, muscle weakness, anxiety, decreased temperature tolerance

  • Graves disease = toxic diffuse goiter (most common)

  • Toxic multinodular goiter

  • Solitary toxic adenoma

  • Iodine-induced hyperthyroidism = Jod-Basedow

  • Thyroiditis

    • Hashimoto thyroiditis = chronic lymphocytic thyroiditis

    • Subacute thyroiditis = de Quervain thyroiditis

    • Painless thyroiditis

    • US:

      • decrease in overall echogenicity

      • discrete nodules (50%)

    • Thyrotoxicosis medicamentosa / factitia surreptitious self-administration of thyroid hormones

    • Struma ovarii = ovarian teratoma containing thyroid tissue

    • Hydatidiform mole / choriocarcinoma / testicular trophoblastic carcinoma = stimulation of thyroid by hCG

    • Pituitary hyperthyroidism = pituitary neoplasm

      • acromegaly

      • hyperprolactinemia

    • Thyroid carcinoma / hyperfunctioning metastases very rare (25 cases)

P.363

Radioiodine Therapy for Hyperthyroidism

• Dose:

  (a) empiric:	15 30 mCi
  (b) calculation (Y):	80 160 Ci/gram

• Calculation:

  Dose [mCi] =

  (gland weight [gram] Y [ Ci/gram]) divided by 24-hour uptake

Hypothyroidism

• PRIMARY HYPOTHYROIDISM (most common)

  • = thyroid's inability to produce sufficient thyroid hormone

  • Agenesis of thyroid

  • Congenital dyshormonogenesis

  • Chronic thyroiditis

  • Previous radioiodine therapy

  • Ectopic thyroid (1:4,000)

• SECONDARY HYPOTHYROIDISM

  • = failure of anterior pituitary to release sufficient quantities of TSH

  • Sheehan syndrome

  • Head trauma

  • Pituitary tumor (primary / secondary)

  • Aneurysm

  • Surgery

• TERTIARY / HYPOTHALAMIC HYPOTHYROIDISM

  • = failure of hypothalamus to produce sufficient amounts of TRH

Decreased / No Uptake of Radiotracer

• BLOCKED TRAPPING FUNCTION

  • Iodine load (most common)

    • = dilution of tracer within flooded iodine pool (from administration of radiographic contrast / iodine-containing medication)

    • Suppression usually lasts for 4 weeks!

  • Exogenous thyroid hormone (replacement therapy) suppresses TSH release

• BLOCKED ORGANIFICATION

  • Antithyroid medication (propylthiouracil (PTU) / methimazole) / goitrogenic substances

  • Tc-99m uptake not inhibited

• DIFFUSE PARENCHYMAL DESTRUCTION

  • Subacute / chronic thyroiditis

• HYPOTHYROIDISM

  • Congenital hypothyroidism

  • Surgical / radioiodine ablation

  • Thyroid ectopia (struma ovarii, intrathoracic goiter) mnemonic: H MITTE

  • Hypothyroidism (congenital)

  • Medications: PTU, perchlorate, Cytomel, Synthroid, Lugol solution

  • Iodine overload (eg, after IVP)

  • Thyroid ablation (surgery, radioiodine)

  • Thyroiditis (subacute / chronic)

  • Ectopic thyroid hormone production

Increased Uptake of Radiotracer

• Thyroiditis (early Hashimoto)

• Hyperthyroidism (diffuse / nodular)

• Rebound after withdrawal of antithyroid medication

• Iodine starvation

• Low serum albumin

• Lithium therapy

• Enzyme defect

Prominent Pyramidal Lobe

• = distal remnant of thyroid descent tract

• Normal variant: present in 10%

• Hyperthyroidism

• Thyroiditis

• S/P thyroid surgery

• DDx:  esophageal activity from salivary excretion (disappears after glass of water)

Thyroid Calcifications

• = benign calcifications = stromal calcifications in adenoma

• coarse calcifications with rough outline

• alignment along periphery of lesion

• irregular distribution

Psammoma Bodies

• = microcalcifications (<1 mm) occur in 54% of thyroid neoplasms

• seen on xeroradiography in 94%

• Papillary carcinoma 61%

• Follicular carcinoma 26%

• Undifferentiated carcinoma 13%

Cystic Areas in Thyroid

• 15 25% of all thyroid nodules!

• Anechoic fluid + smooth regular wall:

  • Colloid accumulation in goiter = colloid-filled dilated macrofollicle

  • Simple cyst (extremely uncommon)

• Solid particles + irregular outline:

  • Hemorrhagic colloid nodule

  • Hemorrhagic adenoma (30%)

  • Necrotic papillary cancer (15%)

  • Liquefaction necrosis in adenoma / goiter

  • Abscess

  • Cystic parathyroid tumor

• bloody fluid = benign / malignant lesion

• clear amber fluid = benign lesion

• Cystic lesions often yield insufficient numbers of cells!

Thyroid Nodule

• Incidence:  (increasing with age)

  • 4 8% by palpation (>2 cm in 2%, 1 2 cm in 5%, <1 cm in 1%); M:F = 1:4

  • 10 41% by thyroid US if clinically normal: multiple in 38%, solitary in 12% (occult small cancers found in 4%)

  • 50% by autopsy

• THYROID ADENOMA

  • Adenomatous nodule (42 77%)

  • Follicular adenoma (15 40%)

  • Ectopic parathyroid adenoma

P.364

• INFLAMMATION / HEMORRHAGE

  • Inflammatory lymph node in subacute + chronic thyroiditis

  • Hemorrhage / hematoma: frequently associated with adenomas

  • Abscess

• CARCINOMA (8 17%)

  • Higher risk of malignancy if

    • patient <20 and >60 years of age

    • Hx of radiation therapy to neck / upper chest

    • family Hx of thyroid cancer / MEN syndrome

    • new nodule in long-standing goiter

    • nodule firm

    • growth rapid

    • nodule fixed to adjacent structures

    • vocal cord paralyzed

    • regional lymph nodes enlarged

  • Thyroid carcinoma

    • papillary carcinoma (70%)

    • follicular (15%)

    • medullary carcinoma (5 10%)

    • anaplastic carcinoma (5%)

    • thyroid lymphoma (5%)

  • Nonthyroidal neoplasm metastasis from breast, lung, kidney, malignant melanoma, Hodgkin disease

  • H rthle cell carcinoma

    • very thin hypoechoic halo

  • Carcinoma in situ

    • echogenic area inside a goiter nodule

Role of fine-needle aspiration biopsy (FNAB)

• FNAB as initial test leads to a better selection of patients for surgery than any other test!; (large-needle biopsy has more complications with no increase in diagnostic yield)

FNA Biopsy Recommendations for Thyroid Nodules

• Diagnostic accuracy (70 97%):

  • 70 80% negative

  • 10% positive specimens (3 6% false-positive rate often due to Hashimoto thyroiditis)

  • 10 20% indeterminate

  • Up to 20% nondiagnostic material (too few cells)

Role of imaging

• Imaging cannot reliably distinguish malignant + benign nodules!

• Radionuclide scanning:

  • Useful in indeterminate cytology

  • Hyperfunctioning nodule is almost always benign!

• US:

  • Best method to determine volume of nodule

  • Useful during follow-up to distinguish nodular growth from intranodular hemorrhage

Discordant Thyroid Nodule

• = nodule warm on Tc-99m pertechnetate scan + cold on I-123 scan, which indicates Tc-99m trapping but no organification

• Cause:

  • Malignancy: follicular / papillary carcinoma

  • <5% of thyroid carcinomas manifest as discordant nodules

• Benign lesion: follicular adenoma / adenomatous hyperplasia

  • (autonomous nontoxic nodules have accelerated iodine turnover and discharge radioiodine as hormone within 24 hours)

Rx: thyroid fine-needle aspiration biopsy

Hot Thyroid Nodule

Incidence:  8% of Tc-99m pertechnetate scans

• Adenoma

  • Autonomous adenoma = TSH-independent

    • euthyroid (80%), thyrotoxicosis (20%)

    • partial / total suppression of remainder of gland

  • Adenomatous hyperplasia = TSH-dependent secondary to defective thyroid hormone production

• Thyroid carcinoma (extremely rare)

  • discordant uptake

• N.B.: any hot nodule on Tc-99m scan must be imaged with I-123 to differentiate between autonomous or cancerous lesion

Cold Thyroid Nodule

• BENIGN TUMOR

  • Nonfunctioning adenoma

  • Cyst (11 20%)

  • Involutional nodule

  • Parathyroid tumor

• INFLAMMATORY MASS

  • Focal thyroiditis

  • Granuloma

  • Abscess

• MALIGNANT TUMOR

  • Carcinoma

  • Lymphoma

  • Metastasis

P.365

• US features of cold nodule:

  • hypoechoic (71%)

  • isoechoic (22%)

  • mixed echogenicity (4%)

  • hyperechoic (3%)

  • cystic (rarely malignant)

• A palpable cold nodule in a patient with Graves disease has a high likelihood of malignancy (4%)!

• mnemonic: CATCH LAMP

  • Colloid cyst

  • Adenoma (most common)

  • Thyroiditis

  • Carcinoma

  • Hematoma

  • Lymphoma, Lymph node

  • Abscess

  • Metastasis (kidney, breast)

  • Parathyroid

• Probability of a cold nodule to represent thyroid cancer:

  • Solitary cold nodules by scintigraphy are multinodular by US in 20 25%!

  • 15 25% for solitary cold nodule

  • 1 6% for multiple nodules (DDx: multinodular goiter)

  • with history of neck irradiation in childhood

    • solitary nodule found in 70% (cancerous in 31%)

    • multiple nodules found in 25% (cancerous in 37%)

    • normal thyroid scan found in 5% (cancer detected in 20%)

P.366

Anatomy and Function of Neck Organs

Paranasal sinuses

• Mucus production of 1 L/day; mucus blanket turns over every 20 30 minutes; irritants are propelled toward nasopharynx at a rate of 1 cm/minute

Maxillary Sinus

Ethmoid Sinuses

• anteromedial ethmoid air cells

  • 2 8 cells with a total area of 24 23 11 mm

    Ostia:

    opening into anterior aspect of hiatus semilunaris of middle meatus (anterior group), opening into ethmoid bulla (middle group)

  • AGGER NASI CELLS

    • = anteriormost ethmoid air cells in front of the attachment of middle turbinate to cribriform plate near the lacrimal duct

    • = anterior, lateral + inferior to frontoethmoidal recess = anteromedial margin of orbit

      Prevalence:

      present in >90%

  • ETHMOIDAL BULLA

    • = ethmoidal air cell above + posterior to infundibulum + hiatus semilunaris, located outside the lamina papyracea at the lateral wall of the middle meatus

  • HALLER CELLS

    • = anterior ethmoid air cells inferolateral to ethmoidal bulla, on lateral wall of infundibulum, along inferior margin of orbit / roof of maxillary sinus, protruding into maxillary sinus

      Prevalence:

      10 45%

• posterior ethmoid air cells

  • 1 8 cells, larger cells, total area smaller than that of anteromedial group

    Location:	behind the basal (= ground) lamella of the middle turbinate
    Ostium:	into superior meatus / supreme meatus, ultimately draining into sphenoethmoidal recess of nasal cavity

  • ONODI CELL

    • = most posterior ethmoid air cell pneumatized into sphenoid bone surrounding the optic canal

      Location:

      superolateral to sphenoid sinus

Frontal Sinus

Sphenoid Sinus

P.367

Ostiomeatal unit

• = area of superomedial maxillary sinus + middle meatus as the common mucociliary drainage pathway of frontal maxillary, and anterior + middle ethmoid air cells into the nose

  Coronal CT:

  visualized on two or three 3-mm-thick sections

• Components:

  • Infundibulum

    • = flattened conelike passage between inferomedial border of orbit / ethmoid bulla (laterally) + uncinate process (medially) + maxillary sinus (inferiorly) + hiatus semilunaris (superiorly)

  • Uncinate process

    • = key bony structure in lateral nasal wall below hiatus semilunaris in middle meatus defines hiatus semilunaris together with adjacent ethmoid bulla

    • pneumatized in <2.5% of patients

  • Ethmoid bulla

    • located in cephalad recess of middle meatus

  • Hiatus semilunaris

    • = final segment for drainage of maxillary sinus; located just inferior to ethmoid bulla in middle meatus

  • Ostia:

    • multiple ostia from anterior ethmoid air cells (at its anterior aspect)

    • maxillary ostium infundibulum (at its posterior aspect)

• Anatomic variations predisposing to ostiomeatal narrowing:

  • Concha bullosa (4 15%) = aerated / pneumatized middle turbinate

  • Intralamellar cell = air cell within vertical portion of middle turbinate

  • Oversized ethmoid bulla

  • Haller cells

    View of Lateral Nasal Wall (turbinates removed)

    Coronal Scan of Ostiomeatal Unit

  • Uncinate process bulla

  • Bowed nasal septum

  • Paradoxical middle turbinate = convexity of turbinate directed toward lateral nasal wall (10 26%)

  • Deviation of uncinate process

  • These conditions are not disease states per se!

Facial buttresses

• = areas of relatively increased bone density that support functional units of the face (muscles, eyes, dental occlusion, airways)

  • of sufficient bone thickness to accomodate metal screw fixation

  • linked directly / through another buttress to cranium / skull base

• horizontal buttresses

  • responsible for facial height

  • Upper transverse maxillary buttress:

    • temporal squamosa zygomatic arch inferior orbital rim nasofrontal junction

      Posterior extension:

      orbital floor

      P.368

      Facial Butresses

  • Lower transverse maxillary buttress:

    • maxilla above alveolar ridge

      Posterior extension:

      hard palate

  • Upper transverse mandibular

  • Lower transverse mandibular

• vertical buttresses

  • responsible for facial profile and width

  • Medial maxillary buttress:

    • anterior nasal spine rim of piriform aperture frontal process of maxilla nasofrontal junction frontal bone

      Posterior projection:	medial orbital wall
      Anterior projection:	lateral nasal wall

  • Lateral maxillary buttress:

    • above posterior maxillary molar zygomaticomaxillary suture body of zygoma lateral orbital rim zygomaticofrontal suture frontal bone

      Posterior projection:

      lateral orbital wall, lateral wall of maxillary sinus

  • Posterior maxillary buttress:

    • pterygomaxillary junction

  • Posterior vertical buttress

Branchial Cleft Development

• 6 paired branchial arches are responsible for formation of lower face + neck; recognizable by 4th week GA

• each branchial arch contains a central core of cartilage + muscle, a blood vessel, and a nerve

• 5 ectodermal clefts / grooves on outer aspect of neck + 5 endodermal pharyngeal pouches separate the 6 arches with a closing membrane located at the interface between pouches and clefts

  Formation:

  during 4th 6th week of embryonic development

1st Branchial Arch = maxillomandibular arch

• large ventral / mandibular prominence

  forms:

  mandible, incus, malleus, muscles of mastication

• small dorsal / maxillary prominence

  forms:	maxilla, zygoma, squamous portion of temporal bone, cheek, portions of external ear
  nerve:	mandibular division of trigeminal nerve (V3)
  pouch forms:	mastoid air cells + eustachian tube
  cleft forms:	external auditory canal + tympanic cavity

  Branchial Apparatus

2nd Branchial Arch = hyoid arch

• cleft involutes completely by 9th fetal week; 2nd arch overgrows 2nd + 3rd + 4th clefts to form cervical sinus, which creates a tract that runs from the supraclavicular area just lateral to carotid sheath, turns medially at mandibular angle between external + internal carotid artery, and terminates in tonsillar fossa

3rd Branchial Arch

• sinks into retrohyoid depression

  nerve:	glossopharyngeal nerve
  arch forms:	glossoepiglottic fold, superior constrictor m., internal carotid a., parts of hyoid bone

• pouch forms:

  • thymus gland, which descends into mediastinum by 9th fetal week

  • inferior parathyroid glands passing down with the thymus

4th Branchial Arch

• sunk into retrohyoid depression

  nerve:	superior laryngeal branch of vagus nerve
  arch forms:	epiglottis + aryepiglottic folds, thyroid cartilage, cricothyroid m., left component of aortic arch, right component of right proximal subclavian a.
  pouch forms:	superior parathyroid glands, apex of piriform fossa
  cleft forms:	ultimobranchial body, which provides parafollicular = C cells of thyroid

P.369

5th + 6th Branchial Arches

• cannot be recognized externally

  nerve:

  recurrent laryngeal branch of vagus nerve

Oral cavity

• comprises lip, upper + lower gingiva, buccal mucosa, hard palate, floor of mouth, anterior 2/3 of tongue

Oropharynx

• consists of

  • pharyngeal wall between nasopharynx + pharyngoepiglottic fold

  • soft palate

  • tonsillar region

  • tongue base

• Borders:

  • superior: soft palate and Passavant ridge (= ridge of pharyngeal muscle that opposes the soft palate when soft palate is elevated)

  • anterior: plane that joins the posterior border of soft palate, anterior tonsillar pillars, circumvallate papillae

  • posterior: posterior pharyngeal wall

  • inferior: vallecula

  • lateral: tonsillar region consisting of anterior tonsillar pillar (= palatoglossus muscle) + palatine / faucial tonsil + posterior tonsillar pillar (= palatopharyngeus muscle)

Hypopharynx

• = compartment of aerodigestive tract between hyoid bone + inferior aspect of cricoid cartilage

• Pyriform sinuses

  • = two symmetric lateral stalactites of air hanging from hypopharynx behind larynx

    • inferior wall: level of cricoarytenoid joint

    • anteromedial wall: lateral wall of aryepiglottic fold

    • lateral wall: abuts posterior ala of thyroid cartilage

    • posterior wall: most lateral aspect of posterior hypopharyngeal wall

  • Postcricoid area = pharyngoesophageal junction extends from level of arytenoid cartilages to inferior border of cricoid cartilage

  • anterior wall of hypopharynx = posterior wall of lower larynx = party wall

• Posterior hypopharyngeal wall

  • extends from level of valleculae to cricoarytenoid joints

Larynx

Supraglottis

• extends from tongue base + valleculae to laryngeal ventricle

• Vestibule = airspace within supraglottic larynx

• Epiglottis

  • = leaf-shaped cartilage that functions as a lid to endolarynx

  • petiole = stem of epiglottis

  • thyroepiglottic ligament = connects petiole to thyroid cartilage inferiorly

  • hyoepiglottic ligament = connects epiglottis to hyoid bone anteriorly, covered by a mucosal fold between the valleculae (glossoepiglottic fold)

  • free margin = superior portion of epiglottis

• False vocal cords

  • = ventricular folds = inferior continuation of aryepiglottic folds = mucosal surface of ventricular ligaments; forming superior border of laryngeal ventricle

• Arytenoid cartilages

• Aryepiglottic folds

  • = mucosal reflections between cephalad portion (= arytenoid processes) of arytenoid cartilage + inferolateral margin of epiglottis

  • soft-tissue folds forming border between lateral pyriform sinuses + central laryngeal lumen

• Laryngeal ventricle

  • = fusiform fossa bounded by crescentic edge of false cords superiorly + straight margin of true cords inferiorly

  • generally not visible on axial scans

• Preepiglottic space

  • low-density tissue between anterior margin of epiglottis + thyroid cartilage

• Paralaryngeal space

  • low-density tissue between true + false cords and thyroid cartilage

  • continuous with preepiglottic space anteriorly + aryepiglottic folds superiorly

Glottis

• True vocal cords

  • = extend from vocal process of arytenoid cartilage to anterior commissure

  • vocal cords adduct during phonation of E / breath holding

• Anterior commissure

  • = midline laryngeal mucosa covering anterior portions of the true vocal cords where they abut the laryngeal surface of the thyroid cartilage

  • <1 mm soft tissue behind thyroid cartilage (during abduction of vocal cords with quiet breathing)

• Posterior commissure

  • = midline laryngeal mucosal surface between attachment of true vocal cords to the arytenoid cartilages

Subglottis

• extends from undersurface of true vocal cords to inferior surface of cricoid cartilage

  • Conus elasticus

    • = fibroelastic membrane extending from cricoid cartilage to medial margin of true vocal cords + forming lateral wall of subglottis

Deep Spaces of Suprahyoid Head & Neck

Masticator Space

• = lateral to parapharyngeal space

• Fascia:

  • superficial layer of deep cervical fascia encloses muscles of mastication

P.370

• Contents:

  • muscles of mastication (medial + lateral pterygoid muscles, masseter, temporalis muscle)

  • ramus + body of mandible

  • cranial nerve V₃

Pharyngeal Mucosal Space

• adenoids, faucial + lingual tonsils

• superior + middle constrictor muscles

• salpingopharyngeal muscle

• levator palatini muscle

• torus tubarius

Parapharyngeal Space

• = triangular-shaped centrally located space; major vertical highway extending from skull base to hyoid

• Fascial borders:

  medial	= middle layer of deep cervical fascia
  lateral	= superficial layer of deep cervical fascia
  posterior	= carotid sheath

• Contents:

  • fat

  • internal maxillary artery

  • ascending pharyngeal artery

  • pharyngeal venous plexus

  • branches of cranial nerve V₃

    Vectors:	if parapharyngeal fat is effaced
    anteriorly	= lesion in masticator space
    medially	= lesion in pharyngeal mucosal space
    laterally	= lesion in parotid space
    posteriorly	= lesion in carotid space

    Transaxial Scan through Level of Lower Nasopharynx

Retropharyngeal Space

• = potential space posterior to pharyngeal mucosal space + anterior to prevertebral space; major vertical highway from skull base to T4

• Fascial borders:

  • mid + deep layers of cervical fascia; alar fascia laterally

• Contents:

  • fat

  • medial + lateral retropharyngeal nodes

Prevertebral Space

• = major highway from skull base to T4; posterior to retropharyngeal space

• Fascial borders:

  • anterior compartment of deep cervical fascia:

    • from one transverse process to the other anteriorly in front of longus colli muscle

  • posterior compartment of deep cervical fascia:

    • from transverse process posteriorly to spinous process

• Contents:

  • prevertebral muscles (longus colli)

  • scalene muscles

  • vertebral artery + vein

  • brachial plexus

  • phrenic nerve

P.371

Carotid Space

• Carotid fascia extends from skull base to aortic arch

• Contents:

  • below hyoid bone:

    • common carotid artery

    • internal jugular vein

    • cranial nerve X (vagus nerve)

    • cervical sympathetic plexus

  • at level of nasopharynx:

    • internal carotid artery

    • internal jugular vein

    • cranial nerves IX XII

    • internal jugular chain of nodes

P.372

Parotid Space

• Contents:

  • parotid gland with Stensen duct

  • intraparotid lymph nodes

  • external carotid + internal maxillary arteries

  • retromandibular vein

  • facial nerve

Submandibular Space

• Contents:

  • submandibular gland with Wharton duct

  • facial artery + vein

  • cranial nerve XII

Temporal bone

• SQUAMOUS PORTION

  • = lateral wall of middle cranial fossa + floor of temporal fossa

• MASTOID PORTION

  • Mastoid antrum

  • Aditus ad antrum

    • connects epitympanum (= attic) of middle ear cavity to mastoid antrum

  • K rner septum

    • = small bony projection extending inferiorly from roof of mastoid antrum as part of petrosquamosal suture between lateral + medial mastoid air cells

• PETROUS PORTION = inner ear

  • Tegmen tympani

    • = roof of tympanic cavity

  • Arcuate eminence

    • = prominence of bone over superior semicircular canal

  • Internal auditory canal (IAC)

    • Porus acusticus internus

      • = opening of internal auditory canal

    • Modiolus

      • = entrance to cochlea

    • Crista falciformis

      • = horizontal bony septum in IAC

  • Vestibular aqueduct

    • = transmits endolymphatic duct

  • Cochlear aqueduct

    • = transmits perilymphatic duct

  • Petrous apex

    • = separated from clivus by petro-occipital fissure + foramen lacerum

• TYMPANIC PORTION

  • External auditory canal (EAC)

    • medial border formed by tympanic membrane, which attaches superiorly at scutum + inferiorly at tympanic annulus

• STYLOID PORTION

Middle Ear

• Borders:

  anterior wall	= carotid wall
  posterior wall	= mastoid wall including

  • facial nerve recess for descending facial nerve

  • pyramidal eminence for stapedius muscle

  • sinus tympani (clinically blind spot)

    superior wall	= tegmen tympani
    inferior wall	= jugular wall
    lateral wall	= tympanic membrane
    medial wall	= labyrinthine wall

• EPITYMPANUM

  • = tympanic cavity above the line drawn between the inferior tip of scutum + tympanic portion of facial nerve

    Contents:

    malleus head, body + short process of incus, Prussak space (= area between incus + lateral wall of epitympanum)

• MESOTYMPANUM

  • = tympanic cavity between inferior tip of scutum + line drawn parallel to inferior aspect of bony EAC

    Contents:

    manubrium of malleus, long process of incus, stapes, tensor tympani muscle (innervated by V3), stapedius muscle (innervated by VII)

• HYPOTYMPANUM

  • = shallow trough in floor of middle ear

Inner Ear

• Cochlea

  • 2 1/2 turns, basal first turn opens into round window posteriorly, encircles central bony axis of modiolus

• Vestibule

  • = largest part of membranous labyrinth with subunits of utricle + saccule (not separately visualized); separated from middle ear by oval window

• Semicircular canals

  • superior semicircular canal forms convexity of arcuate eminence

  • posterior semicircular canal points posteriorly along line of petrous ridge

  • lateral / horizontal semicircular canal juts into epitympanum

• Cochlear aqueduct

  • contains 8-mm long perilymphatic duct, extends from basal turn of cochlea to lateral border of jugular foramen paralleling IAC

    Function:

    regulates CSF + perilymphatic fluid pressure

• Vestibular aqueduct

  • encompasses endolymphatic duct, extends from vestibule to endolymphatic sac

    Function:

    equilibration of endolymphatic fluid pressure

Parotid Gland

• Embryology:

  • glandular component arises from ingrowth of local proliferation of oral epithelium, which creates ducts by 10th week GA; secretions begin by 18th week GA

  • Epithelial buds branch around divisions of facial nerve thus incorporating it into parotid parenchyma

  • The only salivary gland to become encapsulated after development of lymphatic system resulting in intraglandular lymph nodes and lymph vessels

    Location:

    wraps around mandibular angle (within parotid space)

    P.373

    Coronal Tomogram of Temporal Bone

    Axial Tomogram of Temporal Bone

    Coronal Scan of Normal Right Ear

    Axial Scan of Normal Right Ear

P.374

• Anatomic divisions:

  • superficial lobe = main bulk of gland superficial and posterior to masseter muscle; separated by facial nerve from:

  • deep lobe = small extension of gland deep to angle of mandible

  • accessory lobe (20%) = superficial and lateral to masseter muscle + anterior to superficial lobe draining directly into parotid duct

    Drainage route:

    Stensen duct exiting above upper 2nd molar tooth

Thyroid Gland

Thyroxin-binding Globulin

• ELEVATION OF TBG

  • Pregnancy

  • Estrogen administration

  • Genetic trait

• REDUCTION IN TBG

  • Androgens

  • Anabolic steroids

  • Glucocorticoids

  • Nephrotic syndrome

  • Chronic hepatic disease

• INHIBITION OF T4 BINDING TO TBG: salicylates

Parathyroid glands

• SUPERIOR PARATHYROID GLANDS

  Embryology:	derived from 4th pharyngeal pouches, descending together with thyroid gland in close relationship to its posterolateral lobes
  Location:	superior dorsal surface of thyroid gland / intrathyroidal

• INFERIOR PARATHYROID GLANDS

  Embryology:	derived from 3rd pharyngeal pouches migrating caudally with thymus
  Location:	anywhere near / in thyroid, carotid bifurcation, lower neck, mediastinum

• SUPERNUMERARY PARATHYROID GLANDS

  • 5th / 6th gland may occupy an ectopic site

  • Up to 12 parathyroids may be present!

• Surgical success rates for finding parathyroid glands:

  • 95% for initial cervical exploration

  • 60% for repeat surgical exploration

    Cause for failure:

    overlooking an adenoma, multiple abnormal glands, diffuse hyperplasia

• Localization technique:

  • US (75% sensitivity), thallium-technetium subtraction scintigraphy, MR (88% sensitivity)

Thyroid Hormones

P.375

Duplex Identification of Carotid Arteries

P.376

Ear, Nose, and Throat Disorders

Adenoid Cystic Carcinoma

= CYLINDROMA

Location:

• @ Minor salivary glands (most common; 25 31% of malignant neoplasms in minor salivary glands)

  • Most common tumor of the minor salivary glands!

  • nasal obstruction + swelling

  Site:

  oral cavity > pharynx > nose > paranasal sinuses > trachea > larynx

• @ Submandibular gland (15% of tumors in this gland)

• @ Parotid gland (2 6% of tumors in this gland; arises from peripheral parotid ducts with propensity for perineural spread along facial nerve)

  • hard mass + facial nerve pain/paralysis

  • infiltrating parotid mass

MR:

• hypo- to hyperintense (high signal corresponds to low cellularity with a better prognosis) on T2WI

Laryngeal Adenoid Cystic Carcinoma

0.25 1% of all malignant laryngeal tumors

• coughing attacks, wheezing, hemoptysis

• paralysis of recurrent laryngeal nerve due to propensity to invade nerves (CHARACTERISTIC)

• absent history of cigarette smoking

• extensive submucosal tumor spread of entire larynx

• invasion of cricoid cartilage, thyroid + esophagus

• regional neck nodes hardly ever involved

Angiolipoma of parotid gland

= benign nodular lesion similar to ordinary lipomas except for associated angiomatous proliferation

CT:

• circumscribed (more common)/infiltrating mass

• marked enhancement around fatty components

Apical petrositis

= PETROUS apicitis

• Gradenigo syndrome = otorrhea (otitis media) + retro-orbital pain (trigeminal pain) + 6th nerve palsy

• air cell opacification (fluid in ipsilateral middle ear + mastoid)

• bone destruction (osteomyelitis)

MR:

• enhancing mass about petrous tip

Branchial Cleft Anomalies

= failure of involution of branchial clefts leads to branchial cleft cysts/fistula/sinus tracts

First Branchial Cleft Cyst (5 8%)

= PAROTID LYMPHOEPITHELIAL CYST

Residual embryonic tract begins near submandibular triangle

• + ascends through the parotid gland, terminates at junction of cartilaginous + bony external auditory canal

• enlarging mass near lower pole of parotid gland

• recurrent parotid abscesses

• facial nerve palsy

• otorrhea (if cyst drains into EAC)

Pathologic classification (Work):

• cystic mass within gland or immediate periparotid region (superficial to/deep to parotid gland)

• may extend into adjacent fat-containing parapharyngeal space connection to EAC

Second Branchial Cleft Cyst (95%)

= incomplete obliteration of 2nd branchial cleft tract (cervical sinus of His) resulting in sinus tract/fistula/cyst (75%)

Classification (Bailey):

P.377

• history of multiple parotid abscesses unresponsive to drainage + antibiotics

• otorrhea (if connected to external auditory canal)

Location:

• anywhere along a line from the oropharyngeal tonsillar fossa to supraclavicular region of neck; classically at anteromedial border of sternocleidomastoid muscle + lateral to carotid space + at posterior margin of submandibular gland; may be in parapharyngeal space (after extension through stylomandibular tunnel + middle constrictor muscle)

• oval/round cyst near mandibular angle

• displacement of sternocleidomastoid muscle posteriorly, carotid artery + jugular vein posteromedially, submandibular gland anteriorly

• cyst may enlarge after upper respiratory tract infection/injury

US:

• compressible mass internal debris (due to hemorrhage/infection) obscuring its cystic nature

• lack of internal flow

CT/MR:

• beak sign = curved rim of tissue pointing medially between internal + external carotid arteries (PATHOGNOMONIC)

• slight enhancement of capsule

Third Branchial Fistula/Cyst

= above superior laryngeal nerve

• unilocular cystic mass within posterior cervical space

Fourth Branchial Fistula

= below superior laryngeal nerve

• recurrent episodes of suppurative thyroiditis' /neck abscesses

Carotid Artery Aneurysm

= aneurysm of extracranial carotid artery

Etiology:

• Trauma

• Infection (mycotic aneurysm)

• Congenital (very rare): manifestation of connective tissue disorder (Ehlers-Danlos, Marfan, Kawasaki, Mafucci syndrome)

Carotid Artery Stenosis

= High-grade ICA stenosis is associated with increased risk for TIA, stroke, carotid occlusion, embolism arising from thrombi forming at site of narrowing

Increased risk for stroke:

• significant ICA stenosis (compromised blood flow):

  • Reduction of blood flow occurs at 50 60% diameter stenosis/75% area stenosis

  • 2% risk of stroke with nonsignificant stenosis

  • 16% incidence of stroke with significant stenosis

  • 2% incidence of subsequent stroke following endarterectomy

• intraplaque hemorrhage (embolic stroke)

Histo:

• arteriosclerosis = generic term for all structural changes resulting in hardening of the arterial wall

• Diffuse intimal thickening

  • = growth of intima through migration of medial smooth muscle cells into subendothelial space through fenestrations in internal elastic lamella associated with increasing amounts of collagen, elastic fibers, glycosaminoglycans

  Age:	beginning at birth slowly progressing to adult life

• Atherosclerosis

  • = intimal pool of necrotic, proteinaceous + fatty substances within hardened arterial wall

  Location:

  large + medium-sized elastic and muscular arteries

  • fatty streak = superficial yellow-gray flat intimal lesion characterized by focal accumulation of subendothelial smooth muscle cells + lipid deposits

  • fibrous plaque = whitish protruding lesion consisting of central core of lipid + cell debris surrounded by smooth muscle cells, collagen, elastic fibers, proteoglycans; a fibrous cap separates the lipid core (= atheroma) from the vessel lumen

  P.378

  • complicated lesion = fibrous plaque with degenerative changes such as calcification, plaque hemorrhage, intimal ulceration/rupture, mural thrombosis

  • Plaque hemorrhage from thin-walled blood vessels in vascularized plaque may cause ulceration, thrombosis

    • + embolism, and luminal narrowing

    • In 93% of symptomatic patients

    • In 27% of asymptomatic patients

  • Plaque ulceration exposes thrombogenic subendothelial collagen + lipid-rich material

    • Frequent in plaques occupying >85% of lumen

    • 12.5% stroke incidence per year

• M nckeberg sclerosis = medial calcification

• Hypertensive arteriosclerosis

Temporal course of carotid artery stenosis:

• Stable stenosis (68%)

• Progressive stenosis to >50% diameter reduction (25%)

Angiography:

• @ Extracranial

  • smooth asymmetrical excrescence encroaching upon vessel lumen

  • crater/niche = ulceration

  • mound within base of crater = mural thrombus

  • Holman carotid slim sign = diffuse narrowing of entire ICA distal to high-grade stenosis due to decrease in perfusion pressure

  • occlusion of ICA

• @ Intracranial

  • carotid siphon stenosis

  • retrograde flow in ophthalmic artery filled from ECA

  • small vessel occlusion

  • focal areas of slow flow

  • early draining vein = reactive hyperemia = luxury perfusion due to shunting between arterioles + venules surrounding an area of ischemia

  • ICA-MCA slow flow = delayed arrival + washout of ICA-MCA distribution in comparison to ECA

Carotid endarterectomy:

Carotid Duplex Ultrasound

Indications for carotid duplex US:

• Screening for suspected extracranial carotid disease

  • high-grade flow-limiting stenosis

  • low-grade stenosis with hemorrhage

• Nonhemispheric neurologic symptomatology

• History of transient ischemic attack/stroke

• Asymptomatic carotid bruit

• Retinal cholesterol embolus

• Preoperative evaluation before major cardiovascular surgery

• Intraoperative monitoring of vascular patency during endarterectomy

• Sequential evaluation after endarterectomy

• Monitoring of known plaque during medical treatment

Grading of Internal Carotid Stenosis

= severity of stenosis is primarily graded as a ratio of lumen diameter narrowing NOT reduction in cross sectional area

Limitations:

• Calcifications >1 cm in length

  • A jet associated with a >70% stenosis usually travels at least 1 cm downstream!

• Contralateral high-grade stenosis

  • = ipsilateral ICA functions as collateral with increased blood flow velocities

  • Use velocity ratios to compensate for this effect!

• Tortuosity

  P.379

• Increased depth of artery

• High bifurcation

Accuracy of duplex scans (in comparison to arteriography for ICA lesions):

• 91 94% sensitivity, 85 99% specificity, 90 95% accuracy for >50% ICA diameter stenosis

• NORMAL

  • no evidence of plaque

  • peak systolic velocity (PSV) < 125 cm/sec

  • no spectral broadening (clear window under systole)

• MINIMAL DISEASE (0 15% diameter reduction)

  • minimal amount of plaque

  • PSV < 125 cm/sec

  • minimal spectral broadening in deceleration phase of systole

• MODERATE DISEASE (16 49% diameter reduction)

  • moderate amount of plaque

  • peak systole <125 cm/sec

  • end-diastolic velocity (EDV) <40 cm/s

  • poststenotic spectral broadening throughout systole

• SEVERE DISEASE = HEMODYNAMICALLY SIGNIFICANT LESION

  • 50 69% stenosis

    • PSV 125 230 cm/s

    • EDV 40 100 cm/s

  • >70% stenosis (benefit of endarterectomy documented in NASCET study)

    • peak systole >230 cm/s

    • end diastole >100 cm/s

    • peak systolic velocity ratio of ICA/CCA >4.0

• CRITICAL STENOSIS (>95% diameter reduction)

  • PSV and EDV return to normal range/flow undetectable

  • string sign on color Doppler with slow-flow sensitivity setting

• OCCLUSION

  • no signal in ICA on longitudinal/transverse images (color sensitivity + velocity scale must be set low enough to clearly discern flow signals within internal jugular vein)

  • absence of diastolic flow/diastolic flow reversal in CCA (high impedance flow)

  • increased diastolic flow in ECA (if ECA assumes the role of primary supplier of blood to brain)

  • increase in peak systolic velocities in contralateral ICA (due to collateral flow)

Common Carotid Waveform Analysis

• DISTAL OBSTRUCTION

  • high-pulsatility waveform (pulsatility changes occur only with >80% stenosis)

  • reduced amplitude

• PROXIMAL OBSTRUCTION

  • low-amplitude damped waveform

Hemodynamic Variations of Carotid Stenosis

• MORPHOLOGY OF STENOSIS

  • Degree of stenosis: velocities increase up to a luminal diameter of 1.0 1.5 mm

  • Length of stenosis: peak velocities decrease with length of stenosis

  • use the same angle + steering direction when following a patient for disease progression

• PHYSIOLOGIC VARIABILITY

  • A range of velocities may be encountered with a given degree of stenosis!

  P.380

  • ICA/CCA ratio obviates effects of physiologic variability!

  • Compare left with right waveforms to avoid errors!

  • Measure volume flow (more sensitive because of contralateral compensatory flow increase)

Cause:

• Cardiac output

• Pulse rate

• Flow velocity: increased with obstruction in collateral vessels, decreased with proximal obstruction in same vessel

• Normal helical nature of blood flow with many different velocity vectors + nonaxial blood flow not detectable by color Duplex imaging

• Peripheral resistance

• Arterial compliance

• Hypertension

• Blood viscosity

Carotid Plaque

• Asymptomatic patients

  • with diffuse atherosclerotic disease

  Prevalence of >50% stenosis:

  18 20%

• Symptomatic patients:

  • with stroke, TIA, amaurosis fugax as a result of emboli from atheromas at the carotid bifurcation

  Prevalence of >50% stenosis:

  14%

Formation Theory of Carotid Plaque

• Stagnant eddy that rotates at outer vessel margin (opposite to the flow divider in area of flow separation + low shear stress) leads to net influx of fluid into subendothelial tissue with progressive deposition of lipids + smooth muscle cell proliferation

• Increased likelihood of intraplaque hemorrhage (vascularization of plaque with fragile vessels derived from vasa vasorum/from lumen) + fissuring from a critical size on

  • As the degree of stenosis increases, it is more likely that plaques become denser + more heterogeneous demonstrating an irregular surface!

Density of Carotid Plaque

• Hypoechoic = low-echogenicity plaque

  • = fibrofatty plaque/hemorrhage

  • echogenicity less than sternocleidomastoid muscle

  • flow void/flow disturbance on color Duplex

• Isoechoic plaque

  • = smooth muscle cell proliferation/laminar thrombus

  • echogenicity equal to sternocleidomastoid muscle + lower than adventitia

• Hyperechoic = moderately echogenic plaque

  • = fibrous plaque

  • echogenicity higher than sternocleidomastoid muscle + similar to adventitia

• Calcification = strongly echogenic plaque

  • acoustic shadow impairs visualization of intima

Texture of Carotid Plaque

• Homogeneous plaque = stable plaque

  Histo:

  deposition of fatty streaks + fibrous tissue; rarely shows intraplaque hemorrhage/ulcerations

  • Prognosis:

    • Neurologic deficits develop in 4%

    • Ipsilateral infarction on CT in 12%

    • Ipsilateral symptoms develop in 22%

    • Progressive stenosis develops in 18%

  • homogeneous uniform echo pattern with smooth surface (acoustic impedance similar to blood)

• Heterogeneous plaque

  • = unstable plaque = mixture of high, medium, and low-level echoes with smooth/irregular surface; may fissure/tear resulting in intraplaque hemorrhage/ulceration + thrombus formation (embolus/increasing stenosis)

  • B-mode ultrasound has 90 94% sensitivity, 75 88% specificity, 90% accuracy for intraplaque hemorrhage

  Histo:

  lipid-laden macrophages, monocytes, leukocytes, necrotic debris, cholesterol crystals, calcifications

  • Prognosis:

    • Neurologic deficits develop in 27%

    • Ipsilateral infarction on CT in 24%

    • Ipsilateral symptoms develop in 50%

    • Progressive stenosis develops in 77%

  • anechoic areas within plaque (= hemorrhage/lipid deposition/focal plaque degeneration)

  • heterogeneous complex echo pattern

Surface Characteristics of Carotid Plaque

• = US unreliable due to poor visualization of intima

• Intimal thickening

  Histo:

  fatty streaks

  • wavy/irregular line paralleling vessel wall extending >1 mm into vessel lumen

• Ulcerated plaque

  Accuracy:

  60% sensitive, 60 70% specific

  • The presence of intraplaque hemorrhage is much more common than normally appreciated

  • Neither arteriography nor US has proved reliable!

  • isolated crater of >2 mm within surface of plaque demonstrated on transverse + longitudinal images

  • reversed flow vortices extending into plaque crater demonstrated by color Doppler

  • proximal + distal undercutting of plaque

  • anechoic area within plaque extending to surface

Errors In Duplex Ultrasound

• Error in proper localization of stenosis (6%)

  Cause:

  ECA stenosis placed into ICA/carotid bifurcation or vice versa

• Mistaking patent ECA branches for carotid bifurcation (4%)

  P.381

  Cause:

  complete occlusion of ICA not recognized

  • disparity in position of bifurcation

  • no difference in pulsatility waveform

  • high-resistance waveform in CCA

• Interpreter error in estimating severity of stenosis (2.5%):

  • usually overestimation, rarely underestimation

  • absence of one/more components for diagnosis which are

    • significant elevation of peak velocity

    • poststenotic turbulence

    • extension of high velocity into diastole

• Superimposition of ECA + ICA (2%)

  Cause:

  strict coronal orientation of ECA + ICA

  • superimposition can be avoided by rotation of head to opposite side

• Severe stenosis mistaken for occlusion

  • minimal flow not detectable

  • angiogram necessary with delayed images

• Weak signals misinterpreted as occlusion

• Normal/weak signals in severe stenosis

  Cause:

  severe stenosis causes a decrease in blood flow + peak velocity with return to normal velocity levels

  • high resistivity in CCA

• Point of maximum frequency shift not identified

  Cause:

  extremely small lumen/short segment of stenosis

  • unexplained (poststenotic) coarse turbulence

  • ipsilateral ECA collateral flow

  • abnormal CCA resistivity

• Stenosis obscured by plaque/strong Doppler shift in overlying vessel

• Inaccessible stenosis

  • abnormal CCA resistivity

  • abnormal oculoplethysmography

• Unreliable velocity measurements

  • higher velocities: hypertension, severe bradycardia, obstructive contralateral carotid disease, anemia, hyperthryoidism

  • lower velocities: arrhythmia, aortic valvular lesion, CHF, severe cardiomyopathy, proximal obstructive carotid lesion ( tandem lesion ), >95% ICA stenosis

  • aliasing = high velocities are displayed in reversed direction below zero baseline due to Doppler frequency exceeding half the pulse repetition frequency

    Remedy:

    shift zero baseline, increase pulse repetition frequency, increase Doppler angle, decrease transducer frequency, use continuous-wave Doppler probe

Cervical dermoid/epidermoid cyst

• Cystic teratoma

  • teratoma = neoplasm whose tissue is foreign to the part of the body from which the tumor arises

  • epidermoid cyst = epidermal inclusion cyst

    • = lined by simple squamous epithelium without skin appendages

  • dermoid cyst

    • = epithelial-lined cyst containing hair follicles + sebaceous + sweat glands

  • teratoid cyst

    • = lined with squamous/respiratory epithelium containing derivatives of ectoderm + endoderm + mesoderm (skin appendages, nervous/GI/respiratory tissue)

• Nonteratomatous sequestration-type epithelial-lined cyst

  Location:

  • dorsum of nose in infants (most common)

  • midline anterior floor of mouth:

    • sublingual between mylohyoid muscle + tongue (DDx: inclusion cyst, ranula)

    • submental between platysma + mylohyoid muscle

Choanal Atresia

Most common cause of neonatal nasal obstruction!

Associated with other anomalies in 50 75%:

• acrophalyngosyndactyly, amniotic band syndrome, malrotation of bowel, Crouzon syndrome, fetal alcohol syndrome, DiGeorge syndrome, Treacher-Collins syndrome, chromosome 18/12 anomalies, polydactyly, coloboma, facial cleft, CHD, TE fistula, craniosynostosis

• respiratory distress in bilateral choanal atresia (relieved by crying in neonates who are obligate nose breathers during first 2 6 months)

• nasal stuffiness, rhinorrhea, infection in unilateral choanal atresia

Types:

• OSSEOUS/BONY SEPTATION (85 90%)

  Cause: incomplete canalization of choanae

• MEMBRANOUS SEPTATION (10 15%)

  Cause: incomplete resorption of epithelial plugs

• osseomembranous

CT (preceded by vigorous suctioning + administration of topical decongestant):

• narrowing of posterior choanae to a width of <3.4 mm (in children <2 years of age)

• inward bowing of posterior maxilla

• fusion/thickening of vomer

• bone/soft-tissue septum extending across the posterior choanae

Cholesteatoma

• = keratoma

• = epithelium-lined sac filled with keratin debris leading to bone destruction by pressure + demineralizing enzymes

Primary Cholesteatoma (2%)

• = CONGENITAL CHOLESTEATOMA = EPIDERMOID CYST

P.382

• = derived from aberrant embryonic ectodermal rests in temporal bone (commonly petrous apex)/epidural space/meninges

• conductive hearing loss in child with NO history of middle ear inflammatory disease

• cholesteatoma seen through intact tympanic membrane

Location:

• epitympanum

• petrous pyramid: internal auditory canal first involved

• meninges: scooped out appearance of petrous ridge

• cerebellopontine angle: erosion of porus, shortening of posterior canal wall

• jugular fossa: erosion of posteroinferior aspect of petrous pyramid

Secondary Cholesteatoma (98%)

= INFLAMMATORY CHOLESTEATOMA = ACQUIRED EPIDERMOID

Cause:

• ingrowth of squamous cell epithelium of EAC through tympanic membrane (= eardrum) secondary to

  • repeated episodes of ear inflammation with invagination of posterosuperior retraction pocket

  • marginal perforation of eardrum

• whitish pearly mass behind intact tympanic membrane (invasion of middle ear cavity and mastoid) diagnosed otoscopically in 95%

• facial paralysis (compression of nerve VII at geniculate ganglion)

• conductive hearing loss (compromise of nerve VIII in internal auditory canal/involvement of cochlea or labyrinth)

• severe vertigo (labyrinthine fistula)

Types:

• Pars flaccida cholesteatoma = Primary acquired cholesteatoma = Attic cholesteatoma (most common)

  • increasing width of attic

  • initially destruction of lateral wall of attic, particularly the drum spur (scutum) with invasion of Prussak space

  • extension posteriorly through aditus ad antrum into mastoid antrum

  • destruction of K rner septum

• Pars tensa cholesteatoma = Secondary acquired cholesteatoma (less frequent)

  • displacement of auditory ossicles

  • erosion of ossicular chain: first affecting long process of incus

• nondependent homogeneous mass

• perforation of tympanic membrane posterosuperiorly (pars flaccida = Shrapnell membrane)

• poorly pneumatized mastoid (frequent association)

• erosion of tegmen tympani (with more extensive cholesteatoma) producing an extradural mass

• destruction of labyrinthine capsule (less common) involving the lateral semicircular canal first

• erosion of facial canal

MRI:

• iso-/hypointense relative to cortex on T1WI

• no enhancement with Gd-DTPA (enhancement is related to granulation tissue)

Cholesterol Granuloma

= CHOLESTEROL CYST

= acquired inflammatory lesion of petrous bone

• blue (vascular) tympanic membrane without pulsatile tinnitus

• ossicles remain intact

CT:

• nonenhancing middle ear mass

MRI:

• hyperintense signal on T1WI + T2WI secondary to methemoglobin (DDx to cholesteatoma, which is isointense to brain on T1WI)

Chronic Recurrent Sialadenitis

• painful periodic unilateral enlargement of parotid gland

• milky discharge may be expressed

Sialography:

• Stensen duct irregularly enlarged/sausage-shaped

• pruning of distal parotid ducts

• calculi

CT:

• diffusely enlarged dense gland

• dilated Stensen duct calculi

Cx: Mucocele

Cogan Syndrome

= AUTOIMMUNE INTERSTITIAL KERATITIS

MR:

• membranous labyrinthine enhancement

Croup

• = ACUTE LARYNGOTRACHEOBRONCHITIS = ACUTE VIRAL SPASMODIC LARYNGITIS

• = lower respiratory tract infection

• history of viral lower respiratory infection

• hoarse cry + brassy cough

• inspiratory difficulty with stridor

• fever

• thickening of vocal cords

P.383

• NORMAL epiglottis + aryepiglottic folds

• steeple sign = subglottic inverted V = symmetrical funnel-shaped narrowing 1 1.5 cm below lower margins of pyriform sinuses on AP radiograph (loss of normal shouldering of air column caused by mucosal edema + external restriction by cricoid), accentuated on expiration, paradoxical inspiratory collapse, less pronounced during expiration

• narrow + indistinct subglottic trachea on lateral radiograph

• inspiratory ballooning of hypopharynx (nonspecific sign of any acute upper airway obstruction)

• distension of cervical trachea on expiration

  Prognosis:

  usually self-limiting

Dacryocystocele

• 2nd most common cause of neonatal nasal obstruction (after choanal atresia)

• tense blue-gray mass at medial canthus/in nasal cavity

• nasolacrimal duct dilatation

• homogeneous well-defined mass of fluid attenuation

• enhancement of thin wall

• superior displacement of inferior turbinate bone

• contralateral shift of nasal septum

Dermoid Cyst of Neck

• 7% of all dermoid inclusion cysts occur in the head and neck

• slowly growing soft mobile mass in the suprahyoid midline (no movement with tongue protrusion!)

thin-walled unilocular mass

CT:

• homogeneous fluid material of 0 18 HU

• heterogeneous mass (due to various germinal components)

• fluid-fluid level (due to supernatant lipid)

• sack-of-marbles appearance (= coalescence of fat) is PATHOGNOMONIC

• rim enhancement frequent

MR:

• hypointense/hyperintense (sebaceous fluid)/isointense relative to muscle on T1WI

• hyperintense on T2WI + internally heterogeneous

Dissection of Cervicocephalic Arteries

• = hematoma within media splitting off the vessel wall and causing a false lumen within media

• arterial narrowing/occlusion

• intimal flap

• pseudoaneurysm

• embolic distal branch occlusion of intracranial artery

US (50% accuracy):

• echogenic intimal flap

• echogenic thrombus

• dampened/high-resistance Doppler waveform

CECT:

• narrowing/occlusion of contrast-filled artery

MR:

• periarterial rim of hyperintense signal on T1WI + iso- to hyperintense on T2WI around flow void of artery (= intramural hematoma)

• pseudoenlargement of external diameter of artery

Carotid Artery Dissection

• Twice as common as vertebral artery dissection!

• Etiology:

  • SPONTANEOUS CAROTID DISSECTION

    • nonrecalled minor/trivial trauma (frequent)

    • primary arterial disease (rare): Marfan syndrome. fibromuscular dysplasia (in 15%), cystic medial necrosis, collagen vascular disease, homocystinuria

    Associated with:

    hypertension (36%), smoking (47%), migraine (11%)

  • TRAUMATIC CAROTID DISSECTION (rare)

    • blunt/penetrating trauma (automobile accident, boxing, accidental hanging, diagnostic carotid compression, manipulative therapy)

  Associated with:	fracture through carotid canal
  Incidence:	2 5 20% of strokes in persons aged 40 60 years
  Age:	18 76 years (66% between 35 and 50 years)

• unremitting unilateral anterior headache (86%), neck pain (25%)

• TIA/stroke (58%), amaurosis fugax (12%)

• oculosympathetic paresis = Horner syndrome (52%)

• bruit (48%)

  Location:	cervical ICA usually at level of C1 2 (60%) within a few cm of carotid bifurcation > supraclinoid segment of ICA; bilateral carotid dissections (15%)
  Length:	a few centimeters

Angiography:

• string sign = elongated tapered irregular luminal stenosis extending to base of skull (76%)

P.384

• abrupt luminal reconstitution at level of bony carotid canal (42%)

• fingerlike/saccular aneurysm (40%), often in upper cervical/subcranial region

• intimal flap (29%)

• double-barrel lumen similar to aortic dissection (rare)

• slow ICA-MCA flow

• tapered flamelike / radish taillike occlusion (17%), often distal to carotid bulb

Vertebral Artery Dissection

• = hemorrhage into wall of vertebral artery

• headache: occipital (>50%), frontal (20%), orbital (20%)

• neck pain (30%)

MR (modality of choice):

• decreased arterial lumen

• diminished flow void

• periarterial rim signal intensity changes with time (hemoglobin)

Angio:

• tapering of artery/intimal flap/complete occlusion

Epiglottitis

• ACUTE BACTERIAL EPIGLOTTITIS

• life-threatening infection with edema of epiglottis + aryepiglottic folds

• abrupt onset of respiratory distress with inspiratory stridor

• severe dysphagia

Lateral radiograph (frontal view irrelevant):

• Radiograph should be taken in erect position only!

• enlargement of epiglottis + thickening of aryepiglottic folds

• circumferential narrowing of subglottic portion of trachea during inspiration

• ballooning of hypopharynx + pyriform sinuses

• cervical kyphosis

External Auditory Canal Dysplasia

Etiology:

• isolated

• Trisomy 13, 18, 21

• Turner syndrome

• Maternal rubella

• Craniofacial dysostosis

• Mandibulofacial dysostosis

SPECTRUM

• Stenosis of EAC

• Fibrous atresia of EAC

• Bony atresia (in position of tympanic membrane)

• Decreased pneumatization of mastoid (mastoid cells begin to form in 7th fetal month)

• Decreased size/absence of tympanic cavity

• Ossicular changes (rotation, fusion, absence)

• Ectopic facial nerve = anteriorly displaced vertical (mastoid) portion of facial nerve canal

• Decrease in number of cochlear turns/absence of cochlea

• Dilatation of lateral semicircular canal

• bilateral in 29%; M:F = 6:4

• pinna deformity

• stenotic/absent auditory canal

  Cx:	congenital cholesteatoma (infrequent)

Extramedullary Plasmacytoma

= Uncommon form; relatively benign course (dissemination may be found months/years later or not at all); questionable if precursor to multiple myeloma

• usually not associated with increased immunoglobulin titer or amyloid deposition

• mass of one to several cm in size with well-defined lobulated border

Classification:

• Medullary plasmacytoma

• Multiple myeloma:

  • scattered involvement of bone

  • myelomatosis of bone

• Extramedullary plasmacytoma

DDx:

• MULTIPLE MYELOMA

  • = malignant course with soft-tissue involvement in 50 73%:

  • (a) microscopic infiltration

  • (b) enlargement of organs

  • (c) formation of tumor mass (1/3)

  • usually associated with protein abnormalities

  • may have amyloid deposition

  P.385

  Age incidence:

  50 85 years

  • Tends to occur late in the course of the disease and indicates a poor prognosis (0 6% 5-year survival)

Fibromatosis Colli

= rare form of infantile fibromatosis that occurs solely in sternocleidomastoid muscle

• history of difficult delivery (forceps)

• firm soft-tissue mass in lower 1/3 of sternocleidomastoid muscle, which may grow over 2 4 additional weeks

• torticollis (14 20%) due to muscle contraction

• focal/diffuse enlargement of sternocleidomastoid m.

• US:

  • homogeneously enlarged sternocleidomastoid m. without a focal lesion

  • well-/ill-defined mass within sternocleidomastoid muscle:

    • hypo- to iso- to hyperechoic mass depending on duration of disorder

• MR:

  • diffuse abnormal high signal intensity (greater than that of fat) within muscle on T2WI

• CT:

  • isoattenuating homogeneous muscle enlargement

Goiter

Adenomatous Goiter

• = MULTINODULAR GOITER

• US: (89% sensitive, 84% specific, 73% positive predictive value, 94% negative predictive value)

  • increased size + asymmetry of gland

  • multiple 1 4-cm solid nodules

  • areas of hemorrhage + necrosis

  • coarse calcifications may occur within adenoma (secondary to hemorrhage + necrosis)

• Cx: compression of trachea

Diffuse Goiter

US:

• increase in glandular size, R lobe > L lobe

• NO focal textural changes

• calcifications not associated with nodules

Iodine-deficiency Goiter

Not a significant problem in United States because of supplemental iodine in food

• low serum T4

• high I-131 uptake

Jod-Basedow Phenomenon (2%)

• = development of thyrotoxicosis (= excessive amounts of T₄ synthesized + released) if normal dietary intake is resumed/iodinated contrast medium administered

• multinodular goiter with in-/decreased uptake (depending on iodine pool)

Toxic Nodular goiter

• PLUMMER DISEASE

• = autonomous function of one/more thyroid adenomas

• elevated T4

• suppressed TSH

• nodular thyroid with hot nodule + suppression of remainder of gland

• stimulation scan will disclose normal uptake in remainder of gland

• increased radioiodine uptake by 24 hours of approximately 80%

Intrathoracic Goiter

• = extension of cervical thyroid tissue/ectopic thyroid tissue (rare) into mediastinum

• mostly asymptomatic

• symptoms of tracheal + esophageal + recurrent laryngeal nerve compression

• Location:

  • retrosternal (80%) = in front of trachea

  • posterior descending (20%) = behind trachea but in front of esophagus, caudal extent limited by arch of azygos vein, exclusively on right side of trachea

• continuity with cervical thyroid/lack of continuity (with narrow fibrous/vascular pedicle)

• frequent focal calcifications

• CT:

  • mass of high HU + well-defined margins

  • inhomogeneous texture with low-density areas (= degenerative cystic areas)

  • marked + prolonged enhancement

P.386

Graves Disease

• = DIFFUSE TOXIC GOITER

• = autoimmune disorder with thyroid-stimulating antibodies (LATS) producing hyperplasia + hypertrophy of thyroid gland

• elevated T₃ + T₄

• depressed TSH production

• dermopathy = pretibial myxedema (5%)

• ophthalmopathy = periorbital edema, lid retraction, ophthalmoplegia, proptosis, malignant exophthalmos

• diffuse thyroid enlargement

• uniformly increased uptake

• incidental nodules superimposed on preexisting adenomatous goiter (5%)

• global enlargement of 2 3 the normal size

• normal/diffusely hypoechoic pattern

• hyperemia on color Doppler

HIV Parotitis

US:

• multiple hypoechoic/anechoic areas without posterior acoustic enhancement (70%)

• anechoic cysts (30%)

CT/MR:

• bilateral parotid gland enlargement with intraglandular cystic + solid masses

• cervical lymphadenopathy + enlarged adenoids typically associated

Hypopharyngeal Carcinoma

May be associated with:

• Plummer-Vinson syndrome (= atrophic mucosa, achlorhydria, sideropenic anemia) affecting women in 90%

• sore throat, intolerance to hot/cold liquids (early signs)

• dysphagia, weight loss (late signs)

• cervical adenopathy (in 50% at presentation)

  Stage:
  T1	tumor limited to one subsite
  T2	tumor involves >1 subsite/adjacent site without fixation of hemilarynx
  T3	same as T2 with fixation of hemilarynx
  T4	invasion of thyroid/cricoid cartilage/soft tissue of neck

Pyriform Sinus Carcinoma

• may escape clinical detection if located at inferior tip; often origin of cervical adenopathy with unknown primary (next to primaries in lingual + faucial tonsils and nasopharynx)

• invasion of posterior ala of thyroid cartilage, cricothyroid space, soft tissue of neck in T4 lesion

Postcricoid Carcinoma

• difficult assessment due to varying thickness of inferior constrictor + prevertebral muscles

Posterior Pharyngeal Wall Carcinoma

• invasion of retropharyngeal space with extension into oro- and nasopharynx

• retropharyngeal adenopathy

Inverted Papilloma

= INVERTING PAPILLOMA = ENDOPHYTIC PAPILLOMA

• = SQUAMOUS CELL PAPILLOMA = TRANSITIONAL CELL PAPILLOMA = CYLINDRICAL EPITHELIOMA

• = Schneiderian PAPILLOMA

• most often arising from the lateral nasal wall with extension into ethmoid/maxillary sinuses, at junction of antrum + ethmoid sinuses

• paranasal sinus (most frequently maxillary antrum)

• nasal septum (5.5 18%)

• unilateral nasal obstruction, epistaxis, postnasal drip, recurrent sinusitis, sinus headache

• distinctive absence of allergic history

• commonly involves antrum + ethmoid sinus

• widening of infundibulum/outflow tract of antrum

• destruction of medial antral wall/lamina papyracea of orbit, anterior cranial fossa (pressure necrosis) in up to 30%

• septum may be bowed to opposite side (NO invasion)

• homogeneous enhancement

• MR:

  • may have intermediate to low intensity on T2WI (DDx: squamous cell carcinoma, olfactory neuroblastoma, melanoma, small cell carcinoma)

P.387

Juvenile Angiofibroma

• = most common benign nasopharyngeal tumor, can grow to enormous size and locally invade vital structures

• recurrent + severe epistaxis (59%)

• nasal speech due to nasal obstruction (91%)

• facial deformity (less common)

  Location:	nasopharynx/posterior nares
  Extension:	posterolateral wall of nasal cavity; via pterygopalatine fossa into retroantral region/orbit/middle cranial fossa; laterally into infratemporal fossa

• widening of pterygopalatine fossa (90%) with anterior bowing of posterior antral wall

• invasion of sphenoid sinus (2/3) from tumor erosion through floor of sinus

• widening of inferior + superior orbital fissures (spread into orbit via inferior orbital fissure + into middle cranial fossa via superior orbital fissure)

• highly vascular nasopharyngeal mass (only enhances on CT scan immediately after bolus injection); supplied primarily by internal maxillary artery

• MR:

  • intermediate signal intensity on T1WI with discrete punctate areas of hypointensity (secondary to highly vascular stroma)

Labyrinthitis

• sudden hearing loss, vertigo, tinnitus

• MR:

  • faint diffuse enhancement of labyrinth on T1WI (HALLMARK)

Ramsay-Hunt syndrome = herpes zoster oticus

• mucosal vesicles of external auditory canal

• intracanalicular 8th nerve enhancement

Tympanogenic Labyrinthitis

Meningogenic Labyrinthitis