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Dissection of the craniocervical arteries and dural sinus thrombosis L. DIVANO, T. STADNIK, C. MABIGLIA Radiology Department Brugmann Hospital Bruxelles – Belgium XIX SYMPOSIUM NEURORADIOLOGICUM The World Congress of Diagnostic & Therapeutic Neuroradiology Bologna 2010 4-9 October Dissection of the craniocervical arteries INTRODUCTION • 10%–25% of strokes in young patients • spontaneous or traumatic • variety of clinical presentations: stroke, headache, neck pain, tinnitus, Horner syndrome, and cranial neuropathies • neurological emergency because of the risk of cerebral infarct Arterial dissection: diagnostic considerations • Before the development of MR imaging, catheter angiography was considered the study of choice for depiction of carotid and vertebral dissection (limits: cost and invasiveness). • MR imaging/MRA and CT/CTA: alternatives for diagnosis and follow-up Dissection of craniocervical arteries: MRI ADVANTAGES LIMITS • DWI detection of acute stroke • Access to MRI availability, patient restrictions • Axial T1-weighted fatsuppressed depiction of subacute intramural hematoma (crescent sign) • Need for the proper MR imaging protocol • Isointensity of intramural hematoma in the acute phase • Less sensitive for vertebral artery dissection • Confusing high signal intensity caused by the venous plexus or fat surrounding the VAs • Differentiation between intramural hematoma and mural thrombus in an occluded vessel • No X-Rays (youngs, pregnancy & Follow-Up) • No iodine contrast administration Vertinsky AJNR 29 Oct 2008 Arterial dissection: diagnostic considerations Diagnostic clue: intramural hematoma T1 PD TOF-MRA Dissection of the craniocervical arteries: CT ADVANTAGES LIMITS • • Use of ionizing radiation (follow-up studies) • Need for iodine contrast injection Rapid imaging time multiplanar and volume reconstructions • More widely available • Greater spatial resolution • Identification of intimal flaps and pseudoaneurysms • Distinction between a tiny residual patent vessel lumen (string sign) and vessel occlusion Vertinsky AJNR 29 Oct 2008 Arterial dissection: diagnostic considerations Findings of arterial dissection on CT angiography On source images: • narrowing or occlusion of the contrast-filled lumen • the hematoma appears isodense • the residual lumen is generally eccentric Findings of arterial dissection on CT angiography Always check the source images PD FLAIR T2 DWI CTA Both CT and MR angiography show parietal irregularity of the left ICA CE-MRA Findings of arterial dissection on CT angiography thrombosis hematoma is isodense In case of thrombosis, superiority of MRI AJNR 25:769-774, May 2004 Dural sinus thrombosis INTRODUCTION • relatively uncommon, but serious neurological complications: venous infarct • may be associated with high morbidity and mortality • frequently delayed clinical/radiological diagnosis • potentially reversible with prompt diagnosis and appropriate medical care imaging plays a primary role in the diagnosis Dural sinus thrombosis: diagnostic considerations CT limited value in the diagnosis of dural sinus thrombosis: Unenhanced CT: "cord sign" and "dense triangle sign“ - variability (25%) Contrast enhanced CT: "empty delta sign“ - present in only 20 to 30% of cases - false positive possible Giant arachnoid granulations Dural sinus thrombosis: diagnostic considerations CT unenhanced CT can be immediately followed by venography, thus saving time to diagnosis and treatment. CT venography is an effective alternative to MRI American Journal of Roentgenology 169:1699-1707, 1997 Research Journal of Medicine and Medical Sciences, 4(2):284-289, 2009 Dural sinus thrombosis: diagnostic considerations CT-venography ADVANTAGES LIMITS • Widely accessible • Ionizing radiations • Rapid acquisition no motion artifacts • Need for contrast injection • Not affected by slow flow • Time consuming MIP reconstructions and bone subtraction • No contraindication (pacemaker, claustrophobia) N. Khandelwal AJR:187, December 2006 CT-venography with Matched Mask Bone Elimination (MMBE) Dural sinus thrombosis: diagnostic considerations MRI high signal intensity of the venous sinuses with all routine sequences reliable sign of thrombosis. RadioGraphics 2007; 27:95–108 Dural sinus thrombosis: diagnostic considerations MRI After administration of contrast material, the central portion of the sinus typically fails to enhance MR venography shows absence of signal in the affected dural sinus Dural sinus thrombosis: diagnostic considerations MRI ADVANTAGES LIMITS • Early detection of thrombosis • Long acquisition time • Associated parenchymal lesions • Sensitivity to patient motion • No radiations • Flow-related artifacts • (No contrast injection) • Anatomic variability (asymmetric transverse sinus) RadioGraphics 2007; 27:95–108 Sudden onset of altered behaviour and consciousness Pseudotumoral appearance T2 DWI 3D-PC T2* T1+C superior sagittal sinus thrombosis associated with left frontal venous infarction T1 There has been recent interest in evaluating the appearance of intraluminal venous thrombi on DWI. Signal hyperintensity in thrombosed sinuses on DWI has been described. DWI T1+GD RadioGraphics 2006; 26:S19–S43 IN CONCLUSION… Take home messages: dissection of the craniocervical arteries • Availability, contraindications, and patient tolerance will dictate the primary technique to be used: MRI or CT • MRI better shows intramural hematoma and parenchymal lesions • CTA allows better depiction of intimal flaps and pseudoanevrysmal lesions • We must always check the source images • MRI: only DWI and axial T1-weighted fat-suppressed images in patients with a highly suspected dissection on CT/CTA Take home messages: dural sinus thrombosis • Unenhanced CT may show hyperdense thrombosed dural sinus • MRI/MRA is the most often used technique • CT venography (with MMBE) in case of MRI contraindications or ambiguous MRI • CT venography is at least equivalent to MRI in the diagnosis of dural sinus thrombosis THANK YOU FOR YOUR KIND ATTENTION