Diffusion-weighted magnetic resonance imaging in superior sagittal sinus thrombosis

Background and Purpose. Diffusion-weighted imaging (DWI) has shown high sensitivity in the diagnosis of acute arterial strokes. The pathophysiology of cerebral venous thrombosis with associated venous stroke appears to differ from that of arterial strokes. The purpose of this study was to describe DWI findings in venous strokes. Methods, The authors reviewed 3 adults with superior sagittal sinus thrombosis who underwent DWI and magnetic resonance imaging within 24 hours of symptom onset. DWI was obtained at 1.5 T using the multishot echo planar technique (TR = 8000, TE = 97, field of view = 30 x 19 cm, slice thickness = 6.0 mm, interslice gap = 0.5 mm, matrix 128 x 128, NEX = = 1). The diffusion gradients were applied in 3 orthogonal directions with 3 increasing b values (0-1000 s/mm(2)) to create average (trace) DWI images. Apparent diffusion coefficient (ADO) values were calculated on a pixel-by-pixel basis and displayed as ADO maps. Results. DWI showed hyperintensities in patients 1 and 2 and hypointensity in patient 3 in corresponding to parenchymal lesions on conventional images. As compared to the homologous uninvolved location in the contralateral hemisphere, ADO values were decreased (0.53 x 10(-3) mm/s [patient 1] and 0.68 x 10(-3) mm(2)/s [patient 2]) and increased (1.1 x 10(-3) mm(2)/s [patient 3]). The ADO ratio of the lesion in the involved to uninvolved side was 88% (patient 1), 81% (patient 2), and 120% (patient 3). Conclusion. Acute cerebral venous strokes may contain cytotoxic edema and/or vasogenic edema on DWI scans. DWI may be helpful in diagnosing cerebral venous thrombosis in cases with cryptic presentations of SSST by demonstrating thrombosis and lack of venous flow? Prompt diagnosis of SSST is crucial in selecting patients for therapies such as correction of underlying causes and anticoagulation or thrombolysis. The pathophysiology of cerebral venous thrombosis (CVT) with associated venous stroke appears to differ from arterial strokes. Acute arterial strokes show cytotoxic edema, whereas most venous strokes are thought to contain vasogenic and interstitial edema due to venous congestion. Conventional MRI cannot differentiate various forms of edema. Diffusion-weighted imaging (DWI) is a relatively new MRI technique that is highly sensitive in detecting acute arterial strokes and can distinguish cytotoxic and vasogenic edema.(3) Data on the role of DWI in venous strokes secondary to CVT are accumulating.(1,4-9) We report 3 patients with angiography-proven SSST and DWI correlation in the acute phase.