Imaging of disease spread through the skull base

Eufrozina SelariuSkåne Universitetssjukhus Malmö

Sweden

Characterisation of the lesion

Morphology 1. tissue characterisation 2. pattern of bone involvment 3. vascularity Localisation 1. intrinsic to the skull base 2. arrising from intracranial compartment 3. arrising from extracranial head and neck Invasion of other structures 1. Direct extension

• infiltrating bone, soft tissue, meninges, cerebrum• preformed channels and foramina

2. Hematogenous spread 3. Perineural spread

Glomus Jugulare Paraganglioma

Dural arteriovenous fistula

Bone involvement pattern

Agressive bone involvement pattern

Osteolysis Absent bone replaced by soft tissue Thinned bone with soft tissue mass

on its both sides Abnormal signal of the bone marrow Calcifications within the soft tissue

mass

Non-aggressive bone involvement pattern Bone remodeling with bowing, thin or demineralized walls Bone expansion with smooth contour or interrupted walls Enlarged intramedullary cavity Varying attenuation: ground-glass, radiolucent or sclerotic

Eosinophilic granuloma Clivus Chordoma

Juvenil Angiofibroma

Pituitary adenoma

Direct extensionby preformed pathways

EsthesioneuroblastomaOlfactorius meningioma

Trigeminal Neurofibroma

Sphenoid meningioma Optic nerve meningioma

Abscess MPS, PPS, MS, CS, RPS

Pharygeal mucosal space PMS Sinus Morgagni Parapharyngeal space PPS Skull base Carotid space CS Canalis caroticus Jugular foramen Mandibular space MS Foramen ovale Retropharyngeal space RPS Basiocciput

Direct extensionby infiltrating structures

Skull base Metastasis

Occur in bone with high marrow content

Osteoblastic metastasis Hypervascular metastasis Osteolytic metastasis

Frontal sinus Squamous Cell Carcinoma

Sinus frontalis Squamous Cell Cancer with intracranial spread

Nodular dural enhancing have high specificity

Dural thickness > 5 mm Coexistent leptomeningeal

enhancement Brain parenchymal changes

Hematogenous spread

Acute Mastoiditis – Local complications

Subperiosteal abscess Sinus thrombosis Bezold abscess Perisinus and epidural

abscess Petrositis Labyrintitis

Acute OtitisIntracranial complications

Cavernous sinus thrombosisEnlarged superior ophtalmic veinsExophtalmusInhomogenous enhancement of

cavernous sinus

Acute Otitis - Intracranial complications Subdural empyema

Meningitis Petrous apicitis

Perineural spread

Nerve enlargement and nerve enhancement Obliteration of the fat in the foramina, fosse or fissures Foraminal enlargement or destruction Enhancing soft tissue in the cavernous sinus and Meckel cave Neuropathic atrophy and fat replacement

Tumor growth

Incresed permeability of endoneurial capillaries Rupture of the blood-nerve barrier

Contrast-enhancement

Perineural spread

Blood-nerve barrier disruption with segmental nerve enhancement

Inflammation – neuritis Ischemia Trauma Demyelination Axonal degeneration Normal variant enhancement of Gasser ganglion and V2, V3

Adenoid cystic carcinoma Mucoepidermoid carcinoma Squamos cell carcinoma Adenocarcinoma

Ethmoidal Adenocarcinoma with perineural spread in pterigopalatine fossa

Role of imaging

Diagnosis Extent of disease – criteria of surgical resectability Treatment planning – surgical approach Follow-up – reccurence versus posttreatment changes

Thank you !