Gradient-Echo and Segmented-EPI Imaging Comparison in Thrombolytic Treated Patients (IN2-1.004)

Abstract

Objective: The goal of this study was to compare segmented echo-planar imaging (EPI) for detection of HT and thrombus with traditional susceptibility-weighted gradient recalled echo (GRE) in acute stroke patients. Background Hemorrhagic transformation (HT), intra-luminal thrombus, and cerebral microbleeds are seen on GRE. Segmented EPI using a longer echo time (TE) increases the conspicuity of blood without increasing scan time. Design/Methods: Stroke patients treated with tPA were imaged with a 1.5T-General Electric MRI using standard GRE, (TE=25 ms, scan duration=83 seconds), and segmented EPI, (TE=40 ms, 4 segments, scan duration=39 seconds). Two readers blinded to clinical information independently assessed both GRE and EPI, noting presence and type of HT (hemorrhagic infarction (HI1 or HI2) and parenchymal hematoma (PH1 or PH2) and presence and location of thrombus. Results: Forty patients (70.8±14.6 years; 19 women) with median baseline NIHSS=12 (IQR 8-22) were studied. Median time from onset to baseline MRI was 1.8 hours (IQR 1.5-3.0) and to tPA treatment 2.6 hours (IQR 2.1-3.1). HT was seen on 18 patients on GRE (5 HI1, 5 HI2, 5 PH1, 3 PH2), and 17 on EPI (5 HI1, 3 HI2, 5 PH1, 4 PH2); in comparison to GRE, segmented EPI overestimated the severity of HT. Thrombus was detected in 15 patients on either GRE or EPI. Vascular occlusion evaluation yielded 5 confirmed positive for both, 3 could not be independently confirmed, 4 false negative on GRE, 1 was a false negative on EPI, and 2 were false positive on EPI. Conclusions: Segmented EPI adequately detected the presence of HT after tPA treatment, but overestimated its severity in comparison to GRE. Segmented EPI may be more sensitive to detect thrombus at the expense of an increased false positive rate. Segmented EPI may offer a faster MRI alternative in the acute clinical setting. Supported by: The Intramural DIvision of the National Institute of Neurological Disorders and Stroke, National Institutes of Health. Disclosure: Dr. Hernandez has nothing to disclose. Dr. Merino has received personal compensation in an editorial capacity as the Associate Science Editor of AAN.com. Dr. Freeman has nothing to disclose. Dr. Luby has nothing to disclose. Dr. Warach has nothing to disclose. Dr. Latour has nothing to disclose.