Diffusion-Weighted MR Imaging in Cerebral Venous Thrombosis
Background: Cerebral venous thrombosis (CVT) has been an undetermined cause of stroke with an obscure pathophysiology that differs from arterial stroke; its main pathophysiology consists of blood-brain barrier breakdown and coexistence of cytotoxic and vasogenic edema. Conventional MRI cannot allow a prospective differentiation between vasogenic and cytotoxic edema. Diffusion-weighted MRI (DWI) has been reported to detect early ischemic damage (cytotoxic edema) as bright high signal intensity (SI) and vasogenic edema as heterogenous SI. We report various DWI findings in eight patients with CVT. Objectives: To determine the DWI findings and pathophysiology of CVT Results: From November 1998 to July 2000, eight consecutive patients (two men, six women, age 46 ± 11 years) with CVT underwent DWI, conventional MRI, MR venography and/or conventional cerebral angiography. DWI findings were grouped as three patterns. The first pattern was heterogenous SI (five patients). Bright high SI and low SI were mixed and the corresponding apparent diffusion coefficient (ADC) values were inversely correlated to the DWI SI. The areas of prominent low SI were reversed with adequate treatment in follow-up MR imagings. Second, multifocal high SI, like acute arterial stroke, was found in two patients. The corresponding ADC values were decreased. The third type was intravascular clot high SI (two patients) with or without parenchymal lesions. In one patient, DWI demonstrated T2-negative lesion without correlative symptoms. Conclusions: Herein, we classified DWI abnormalities in CVT and these data suggest that DWI can be utilized for discriminating types of edema for tissue viability, detecting subclinical abnormality for preventing further deterioration, and furthermore basic research about the mechanisms of cell death in CVT.