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Cavernous Sinus Syndrome Imaging: A Myriad of Etiologies Aleema Patel, Wilson Altmeyer, Cedric W. Pluguez-Turull, Bundhit Tantiwongkosi, Achint K. Singh eEdE-34

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Disclosures None of the authors have any financial relationships to disclosure

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Educational Objectives 1.Review cavernous sinus syndrome 2.Familiarize with cavernous sinus anatomy 3. Describe the common causes of cavernous sinus syndrome 4. Discuss imaging appearances of different pathologies associated with cavernous sinus syndrome

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Cavernous Sinus Anatomy Oculomotor Nerve (III) Trochlear Nerve (IV) Abducens Nerve (VI) Ophthalmic Nerve (V1) Maxillary Nerve (V2) Cavernous Sinus Optic Chiasm Internal Carotid Artery Sphenoid Sinus Internal Carotid Artery Hypophysis (pituitary gland)

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Cavernous Sinus Anatomy Paired collection of thin walled veins between the endosteal and meningeal dural layers located at the center of the head which drains intracranial blood Anterior Border = Superior orbital fissure Posterior Border = Petroclinoid fold and Clivus dura matter Inferolateral Border =Inner middle cranial fossa Lateral Border = Outer dural meningeal layer with deeper inner nerve containing layer Medial Border = Sella turcica

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Cavernous Sinus Anatomy Venous Flow Receives venous tributaries from the superior and inferior ophthalmic veins and superficial cortical veins Drains into the superior and inferior petrosal sinuses Connected to the venous basilar plexus posteriorly

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Cavernous Sinus Anatomy Nerves Lateral wall, superior to inferior CN III: Occulomotor nerve CN IV: Trochlear nerve CN V1: Ophthalmic nerve, the V1 branch of the trigeminal nerve CN V2: Maxillary nerve, the V2 branch of CN V Paralleling internal carotid artery CN VI: Abducens nerve Artery Internal carotid artery Bends as the cavernous, C4 segment Bifurcates Meningohypophyseal trunk & Inferolateral trunk

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Imaging Anatomy of Cavernous Sinus Normal thin wall enhancement of cavernous sinus Internal Carotid Arteries Axial T1-W FS post gad MRCoronal T1-W FS post gad MR

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Cavernous Sinus Syndrome Definition Syndrome caused by thrombosis of the cavernous sinus Symptoms Edema of the eyelids and conjunctivae Paralysis of extra-ocular muscles supplied by the CN III, CN IV, and CN VI

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Cavernous Sinus Lesions Tumors Carotid Artery Aneurysm Carotid Cavernous (C-C) Fistula Thrombosis Tolosa-Hunt Syndrome

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Cavernous Sinus Tumors Most common etiology of cavernous sinus syndrome Primary tumors Schwannoma Neurofibroma Meningioma Hemangioma Lymphoma Secondary involvement/Metastatic disease Pituitary Adenoma Nasopharyngeal carcinoma Perineural spread of tumor through neural foramina Base of skull tumor Chondrosarcoma Osteosarcoma

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Pituitary Macroadenoma May grow laterally and invade the cavernous sinus Cavernous Sinus Invasion Encasement of the intracavernous internal carotid artery by >30% of its diameter or tumor extension lateral to the top (12 oclock) of the internal carotid artery Does not narrow internal carotid artery unlike meningiomas Presence of abnormal soft tissue between the lateral wall of the cavernous sinus and the internal carotid artery

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Pituitary Macroadenoma with Cavernous Sinus Invasion Large enhancing pituitary mass extending to the right cavernous sinus and encasing the right ICA Sagittal T1-W post gad MR Coronal T2-W MR Axial T1-W post gad MR Coronal T1-W post gad MR

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Meningioma Most cavernous sinus meningiomas arise from the lateral dural wall Sometimes arise exclusively inside the cavernous sinus Imaging: Hypo- to isointense with respect to gray matter on all MR imaging sequences Intense enhancement Dural tail frequently can be seen extending away from the edge of the tumor and often into the ipsilateral tentorium Constrict the lumen of the ICA Helps differentiate from pituitary adenomas Extend inside the cavernous sinus and the Meckel cave and via the porous trigeminus into the prepontine cistern Often difficult to distinguish from schwannomas

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Meningioma T2 isointense left cavernous sinus meningioma with narrowing of the left ICA Axial T1-W post gad MR Axial T2-W MR Coronal T1-W post gad MR

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Trigeminal Nerve Schwannoma Commonly involves the cavernous sinus Multiple cavernous sinus schwannomas and bilateral vestibular schwannomas are seen in patients with neurofibromatosis type 2 50% have dumbbell-shape with bulky tumor in the Meckel cave and the prepontine cistern and a waist at the porous trigeminus May also be found only involving the Meckel cave Imaging Solid, variable cystic, or hemorrhagic components +/- fluid levels Small tumors homogeneous Large tumors heterogeneous in appearance T1 isointense-to-hypointense T2 hyperintense Enhance with contrast Follow the expected course of the nerves from which they arise May arise from other cranial nerves in the cavernous sinus, especially cranial nerve III

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Trigeminal Nerve Schwannoma T2 hyperintense mass in the right cavernous sinus with retrograde extension along the cisternal segment of right CN V Axial T1-W post gad MRSagittal T1-W MR Coronal T1-W post gad MR Axial T2-W MR

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Plexiform Neurofibromas Most commonly involve the trigeminal nerve, typically the first and second branches Seen in 30% of patients with neurofibromatosis type 1 but are extremely rare outside this disease Imaging: Tortuous or fusiform enlargement of the nerves that exhibit heterogeneous signal intensity Neurofibromas are less likely to extend to the Meckel cave unlike schwannomas

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Plexiform Neurofibromas Multiple plexiform neurofibromas in a patient with NF-1 with one of the neurofibromas extending into the right cavernous sinus Axial T1-W post gad MRAxial T2-W MR

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Nasopharyngeal Carcinoma Most common primary malignant extracranial neoplasm to invade the cavernous sinus Intracranial extension directly via the skull base erosion or by perineural spread along branches of the trigeminal nerve Can extend through the petro-occipital synchondrosis and foramen lacerum into the inferior cavernous sinus or via the carotid canal to gain access to the cavernous sinus without destroying bone Imaging: Hypointense to iso-intense relative to muscles on T1-weighted images T2 hypointense Moderate-to-intense contrast enhancement

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Nasopharyngeal Carcinoma Left nasopharyngeal mass with extension in the left cavernous sinus Axial T1-W FS post gad MR Axial T2-W MR Axial T1-W post gad MR Coronal T1-W FS post gad MR

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Cavernous ICA Aneurysm Composes 5% of giant aneurysms (>2.5 cm in diameter) Most of these aneurysms are idiopathic, occasionally traumatic or mycotic More frequent in the elderly population Produces cavernous sinus syndrome by mass effect, inflammation, or rupture into the CS, with subsequent development of a carotid cavernous fistula Can present with an indolent ophthalmoplegia Endovascular occlusion is often successful treatment

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Cavernous ICA Aneurysm Imaging: Patent aneurysm Signal-intensity void on spin-echo MR Partially thrombosed giant aneurysms Mixed signal intensities Due to clot in lumen or in walls secondary to chronic dissections Flowing blood through the patent portion of the lumen appears as a signal-intensity void on spin-echo images and high signal intensity on gradient techniques

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Cavernous ICA Aneurysm CTA CTA: Coronal MIP

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Carotid Cavernous (C-C) Fistula Abnormal connection between the carotid artery and the cavernous sinus Four Types Type A (Direct): High-flow communication between the internal carotid artery and cavernous sinus secondary to trauma or a ruptured aneurysm of the cavernous internal carotid artery Present acutely with pulsating exophthalmos, chemosis, visual loss, and ophthalmoplegia Types B-D (Dural CCFs): Low-flow fistulas occurring between meningeal branches of the carotid artery and cavernous sinus Milder symptoms with more insidious presentation than direct fistulas Often resolve spontaneously Treated by endovascular occlusion techniques by interventional radiology Occasionally, surgical treatment with carotid ligation is necessary; this sometimes is preceded by a superficial temporal-to-middle cerebral bypass operation to ensure cerebral circulation after carotid ligation MR Imaging Findings: Dilated cavernous sinus with multiple signal-intensity void structures Proptosis & enlarged superior ophthalmic vein Flow-related enhancement in the cavernous sinus on TOF MR angiography suggests the diagnosis in the right clinical setting Dirty appearance of the retro-orbital fat & enlargement of the extraocular muscles Enlargement of bilateral cavernous sinuses in setting of very high-flow fistulas

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Carotid-Cavernous (C-C) Fistula Enlarged right superior ophthalmic vein with early arterial enhancement of the right cavernous sinus suggestive of carotid cavernous fistula CTA

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Cavernous Carotid (C-C) Fistula: Case 2 Early arterial enhancement, flow voids and arterial signal on the TOF MR of the cavernous sinus suggestive of cavernous carotid fistula Axial T2-W MR Axial TOF MR Axial CTA

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Cavernous Carotid (C-C) Fistula: Case 2 Arterial enhancement of the cavernous sinus Post gad MRA: Oblique Coronal MPR

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Cavernous Sinus Thrombosis Often secondary to infection of the sinonasal cavities, orbits, and/or the middle 1/3 of face MR Imaging: Changes in signal intensity and/or in the size and contour of the cavernous sinus Enhancement of the peripheral margins of an enlarged cavernous sinus Subacute thrombus demonstrates high signal intensity on all pulse sequences easy to recognize Acute thrombosis often isointense difficult to diagnose Indirect signs Dilation of the superior ophthalmic veins Exophthalmos Increased dural enhancement along the lateral border of cavernous sinus and ipsilateral tentorium Diagnosis confirmed by presence of sinusitis and clinical symptoms

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Cavernous Sinus Thrombophlebitis Enlarged non- enhancing left superior ophthalmic vein (compared with right) Enlarged left cavernous sinus with subtle central hypointensity Enlarged extraocular muscles Coronal T1-W FS post gad MR Coronal CT Axial T1-W FS post gad MR Axial CT

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Cavernous Sinus Thrombosis: Case 2 Acute fulminant invasive mucormysosis with sphenoid sinusitis complicated by acute cavernous sinus thrombosis Axial CT

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Tolosa-Hunt Syndrome Retro-orbital pseudotumor extending to the cavernous sinus Clinical triad Unilateral ophthalmoplegia Cranial nerve palsies Dramatic response to systemic corticosteroids Usually unilateral but may be bilateral (5%) Histopathology = low-grade nonspecific inflammatory process with lymphocytes and plasma cells MR Imaging Enlarged cavernous sinus containing abnormal soft tissues that are isointense to muscle on T1-weighted images and dark or bright on T2- weighted images and display contrast enhancement with focal narrowing of the ICA

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Tolosa-Hunt Syndrome T2 iso-hypointense signal in the left cavernous sinus with enhancement Enhancement is also seen in the left superior orbital fissure Axial T2-W MR Axial T1-W FS post gad

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Summary Cavernous sinus syndrome is a complex constellation of symptoms caused by a broad range of pathology Pathology is shaped by variety of anatomic structures within and adjacent to the cavernous sinus

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Conclusions Careful examination of the cavernous sinus by radiologists is imperative to ensure detection of lesions

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References Bone, I, and Hadley, D. 2005. Syndromes of the orbital fissure, cavernous sinus, cerebello- pontine angle, and skull base. BMJ Group. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1765699. Keane JR. 1996. "Cavernous sinus syndrome. Analysis of 151 cases". Archives of Neurology. 53 (10): 967-71. Kline LB, and WF Hoyt. 2001. "The Tolosa-Hunt syndrome". Journal of Neurology, Neurosurgery, and Psychiatry. 71 (5): 577-82. Lee JH, HK Lee, JK Park, CG Choi, and DC Suh. 2003. "Cavernous sinus syndrome: clinical features and differential diagnosis with MR imaging". AJR. American Journal of Roentgenology. 181 (2): 583-90. Razek AA, and M Castillo. 2009. "Imaging lesions of the cavernous sinus". AJNR. American Journal of Neuroradiology. 30 (3): 444-52. Yousem DM, SW Atlas, RI Grossman, RC Sergott, PJ Savino, and TM Bosley. 1990. "MR imaging of Tolosa-Hunt syndrome". AJR. American Journal of Roentgenology. 154 (1): 167-70.