MR susceptibility sign of the middle cerebral artery in imaging of acute stroke

To evaluate the accuracy of echo-planar T2-weighted, compared to MRA and FLAIR in the detection of acute middle cerebral artery [MCA] thrombotic occlusion. 47 consecutive patients with acute stroke involving the MCA territory underwent MR imaging within 2 to 76 hours after clinical onset. MR examination included echo-planar T2-weighted-, FLAIR, diffusion-weighted-imaging [DWI] and MR-angiography [MRA]. The susceptibility sign on echoplanar T2-weighted images, which is indicative of acute thrombotic occlusion involving the MCA, was assessed and compared to findings on MRA and axial FLAIR in all patients and to CT in 23 patients. National Institutes of Health Stroke Scale [NIHSS] score, which is a clinical scale assessment, was used for evaluating the neurological status of patients. Fourty seven [47] patients [29 males; age range 11-86years [mean: 58.3 +/- 14.7 yrs] and 18 females; age range 35-83 years [mean: 59.4 +/- 12.7 yrs] with acute territorial MCA infarcts were included in this study. Out of these 47 patients, 10 had hyperacute MCA infarction [scanned 2-6 hours after ictus], 7 of those patients presented with very severe stroke [NIHSS score 21 or more] and 3 patients with severe stroke [NIHSS score 15-20]. Thirty seven [37] patients were studied within 76 hours from ictus [acute to early subacute]. Among this group and according to NIHSS score, 5 patients had mild to moderate stroke, 16 patients severe stroke; and 13 patients had very severe stroke. One patient who had very severe stroke with NIHSS score of 22, died. She had left MCA occlusion, presented 4 hours within onset of right hemiplegia and had a history of DM, HTN and COPD. Presence of the susceptibility sign on T2 WI proximal to the MCA bifurcation provides fast and accurate detection of acute proximal MCA thrombotic occlusion. It is considered a warning sign for rapid and efficient intervention for stroke treatment, including thrombolysis and can be used for follow up of thrombus evolution

Role of b0 image obtained from diffusion weighted sequence in detection of cerebral hemorrhage

Gradient-echo [GRE] -weighted imaging [T2*WI] has higher sensitivity than do other MRI sequences used for detecting cerebral hemorrhage as it is sensitive to magnetic field in homogeneity induced by the presence of the paramagnetic breakdown products of blood. Diffusion weighted [DWI] b0 image obtained with DWI imposes no additional time and could be used for detection of hemorrhage. An Echo-planner Imaging [EPI] is intrinsically sensitive to magnetic field in homogeneity, paramagnetic blood breakdown products, it produces signal loss similar to that in T2*WI. The aim of this study is to evaluate the utility of b0 EPI image obtained from diffusion weighted sequence for detection of intracerebral hemorrhage. The study included 26 patients from Ain-Shams specialized hospital with different stages of intracerebral hemorrhage [ICH]. All patients had MRI examination including DWI including b0 image, T2*WI, TIWI, T2WI, Fluid attenuation inversion recovery sequence [FLAIR], and MRA. Radiologists reviewed the images of the examinations independently in a blinded fashion, followed by a final consensus reading. The sensitivity of hemorrhage detection, conspicuity of lesions, and diagnostic certainty were compared between the b0 EPI and GRE T2*WI sequences. b0 image was 100% sensitive in detecting different stages of intracerebral hemorrhage in the study sample [acute, subacute and chronic]. b0 image was as equal to T2*WI in detection of hemorrhage in 92.30% of cases [24 cases out of 26], in one patient b0 detected hemorrhage more clearly than T2* WI, while in the remaining patient T2*WI detected hemorrhage more clearly than b0 image. b0 EPI is as sensitive as T2*WI in detecting different stages of intracerebral hemorrhage