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 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

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 Arterial dissection: diagnostic considerations

Dissection of craniocervical arteries: MRI ADVANTAGES DWI  detection of acute stroke Axial T1-weighted fat- suppressed  depiction of subacute intramural hematoma (crescent sign) Differentiation between intramural hematoma and mural thrombus in an occluded vessel No X-Rays (youngs, pregnancy & Follow-Up) No iodine contrast administration LIMITS Access to MRI  availability, patient restrictions 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 Vertinsky AJNR 29 Oct 2008

T1PD TOF-MRA Arterial dissection: diagnostic considerations Diagnostic clue: intramural hematoma

Dissection of the craniocervical arteries: CT LIMITS Use of ionizing radiation (follow-up studies) Need for iodine contrast injection Vertinsky AJNR 29 Oct 2008 ADVANTAGES 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

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 Arterial dissection: diagnostic considerations

Findings of arterial dissection on CT angiography Always check the source images

PD FLAIR T2 DWI

CE-MRA CTA Both CT and MR angiography show parietal irregularity of the left ICA

Findings of arterial dissection on CT angiography thrombosis hematoma is isodense

In case of thrombosis, superiority of MRI AJNR 25: , 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

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: , 1997 Research Journal of Medicine and Medical Sciences, 4(2): , 2009 Dural sinus thrombosis: diagnostic considerations CT

ADVANTAGES Widely accessible Rapid acquisition  no motion artifacts Not affected by slow flow No contraindication (pacemaker, claustrophobia) LIMITS Ionizing radiations Need for contrast injection Time consuming MIP reconstructions and bone subtraction Dural sinus thrombosis: diagnostic considerations CT-venography N. Khandelwal AJR:187, December 2006

CT-venography with Matched Mask Bone Elimination (MMBE)

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 Early detection of thrombosis Associated parenchymal lesions No radiations (No contrast injection) LIMITS Long acquisition time Sensitivity to patient motion Flow-related artifacts Anatomic variability (asymmetric transverse sinus) Dural sinus thrombosis: diagnostic considerations MRI RadioGraphics 2007; 27:95–108

Sudden onset of altered behaviour and consciousness Pseudotumoral appearance

superior sagittal sinus thrombosis associated with left frontal venous infarction T2 DWI T2*T1+C 3D-PC

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. RadioGraphics 2006; 26:S19–S43 T1 T1+GD DWI

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

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