Characteristic Signs on T2*-Based Imaging and Their Relationship with Results of Reperfusion Therapy for Acute Ischemic Stroke: A Systematic Review and Evidence to Date / 신경중재치료의학

PURPOSE: Characteristic signs – the susceptibility vessel sign (SVS) and the prominent hypointense vessel sign (PHVS) – on T2*-based magnetic resonance imaging (T2*MRI) can be seen for acute ischemic stroke with large artery occlusion. In this study, we investigated the evidence to support our hypothesis that these findings may help to predict outcomes after reperfusion therapy. MATERIALS AND METHODS: We searched for papers describing SVS and PHVS in patients treated with reperfusion therapy for acute ischemic stroke, and their functional/radiologic outcomes were systematically reviewed. RESULTS: Nine studies on the SVS and six studies on the PHVS were included. The pooled odds ratio (OR) of recanalization after intravenous thrombolysis or mechanical thrombectomy was not significantly different with the presence of SVS (OR, 0.615; 95% confidence interval [CI], 0.335–1.131 and OR, 0.993; 95% CI, 0.629–1.567). The OR of favorable functional outcome after reperfusion therapy in terms of the presence of PHVS varied (0.083 to 1.831) by study. CONCLUSION: Our meta-analysis of the published data showed that a SVS was not a predictive factor for recanalization after reperfusion therapy for acute ischemic stroke. Currently, the data available on T2*MRI are too limited to warrant reperfusion therapy in routine practice. More data are needed from studies with randomized treatment allocation to determine the role of T2*MRI.

Applied value of susceptibility-weighted imaging in acute ischemic stroke / 医疗卫生装备

Objective To evaluate the applied values of susceptibility weighted imaging (SWI) in acute ischemic stroke.Methods Totally 40 patients with acute ischemic stroke were included within 72 hours after symptom onset.They adopted multimodal magnetic resonance imaging examination,including regular magnetic resonance imaging sequence (T1WI,T2WI),time of flight MR angiography (TOF-MRA),diffusion weighted imaging (DWI) and susceptibility weighted imaging (SWI).Furthermore,12 of the 40 patients received dynamic susceptibility contrast enhanced perfusion weighted imaging (DSCPWI) examination.Results Of the 40 patients,12 ones had positive results for multiple lesions of cerebral microbleeds (CMBs) by SWI,and the detection rate was 30％.There were 24 patients showed susceptibility vessel sign (SVS) in SWI,and the susceptibility rate was 60％.In the 12 patients received DSC-PWI examination simultaneously,there were 7 cases had the anomaly range by SWI larger than that by DWI while similar to that by DSC-PWI.Conclusion SWI can show SVS and CMBs clearly,estimate ischemic penumbra,know intracranial conditions completely and supply reliable basis for individualized treatment.

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

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.

A newly Developed Hyperintensity Within a Posterior Cerebral Artery Susceptibility Vessel Sign in T2*-Weighted Gradient-Echo Imaging: a Case Report and Correlation with Magnetic Resonance Angiography and Black-Blood Imaging

The susceptibility vessel sign (SVS) on T2*-weighted gradient-echo imaging (T2*-GRE) is useful for detecting intra-arterial clots and monitoring the response to thrombolysis. SVS-GRE was observed in a 52-year-old man with acute occlusion of the posterior cerebral artery (PCA) before and after failed intra-arterial thrombolysis. One-week follow-up T2*-GRE revealed a hyperintensity within the SVS-GRE in the affected PCA. The right PCA remained occluded on time-of-flight (TOF) magnetic resonance angiography (MRA), but its P2 segment exhibited luminal patency on contrast-enhanced (CE) MRA. Black-blood MR imaging using a T1-weighted turbo-spin echo sequence revealed narrowing of the arterial lumen and thickening of the wall due to an atherosclerotic plaque. The observations from TOF-MRA, CE-MRA, and black-blood MR imaging suggest that a newly developed hyperintensity within the SVS-GRE seems to be associated with slow flow through a severe atherosclerotic stenosis or near-occlusion.