Diagnostic Value of Thrombus Size on T2*-weighted Gradient Echo Imaging in Acute Middle Cerebral Artery Occlusion

ABSTRACT

OBJECTIVE: The T2*-weighted gradient echo image susceptibility vessel sign (GRE SVS) is a well-known indicator of intraluminal thrombi in acute cerebral infarction. The purpose of this study was to evaluate the relationships between thrombus size on GRE SVS and recanalization after intravenous administration of tissue plasminogen activator (IV-tPA). MATERIALS AND METHODS: Fifty five patients with GRE SVSs on the M1 were enrolled. Examination of magnetic resonance image (MRI), including diffusion weighted imaging and MR angiography, was performed within 20 minutes of admission. Thrombus size on GRE was calculated using the Picture Archiving and Communication System upon initial MRI. Recanalization was assessed with follow-up MRI or transfemoral cerebral angiography within 24 hours of treatment. RESULTS: The patient group consisted of 37 males and 18 females with an average age of 63.74 +/- 10.28 years (range 43 - 77 years). The median NIHSS score was 13. Fifteen of these patients achieved recanalization (27.3%). The average thrombus cross-sectional area in the recanalization group was 38.54 +/- 20.27 mm2, and the corresponding size of the non-recanalization group was 53.38 +/- 24.77 mm2 (p = 0.043). In the receiver operator characteristic curve for thrombus cross-sectional area in relation to recanalization, the cut-off point was 47.28 mm2. The sensitivity at this cut-off point was 73.3%, the specificity was 60%, and the area under the curve was 0.687. CONCLUSION: Thrombus size on GRE is a simple diagnostic tool that can be easily measured, and thrombus size on GRE SVS was found to be associated with recanalization after IV-tPA.