| AbstractAcute ischemic stroke and acute intracerebral hemorrhage (ICH) may show the similar neurological deficits . Differentiating acute infarction from acute cerebral hemorrhage is important because these diseases necessitate different therapies . Magnetic Resonance Imaging is now a promising technique for early detection of cerebral infarction in routine clinical practice.Computed Tomography is commonly considered the "gold standard" in diagnosing ICH,but CT may yield the false results in small hemorrhage or acute subarachnoid hemorrhage.A number of previous studies claiming that MRI is insensitive to the detection of acute ICH were performed at a low field strength. In this study,we discussed the value of MRI in diagnosing acute ICH by examining 36 ICH patients with 1.5T MRI and comparing the results with CT.Materials and methodsExperiment materials: This study used 32 rabbits weighing from 2.0-3.0kg.Male 12,female 20.Eight rabbits served as control, each of the other 24 rabbits was anesthetized with 2.5% pentobarbital (3mg/kg) and placed in a stereotactic frame. A 1 ml needle was introduced through a hole into the caudate nucleus and 0.2-0.3ml blood of rabbit was infused immediately. After the infusion the needle was remained for 8 minutes and then removed.CT technical material: All patients were examined with a high-speed spiral CT ( Toshiba Aquilion 16). The volume of hematoma was calculated.MRI scan protocol and technical material: For MR imaging ,a 1.5-T scanner (Signa Horizon LX; GE Medical Systems)was used.The conventional MR imaging protocol included axial T1WI SE: 380ms/10ms(TR/TE),256 X 192matrix, 14 FOV, 3 NEX and a 3mm/0.5mm slicethickness/intersection gap; axial T2WI FSE 4000ms/ 102ms(TR/TE), 320×224matrix,ETL24, 14 FOV, 3 NEX and a3mm/0.5mm slicethickness/intersection gap; axial T2*WI GRE,350ms/Minfull(TR/TE), 256 X 244matrix, 14 FOV, 3 NEX and a3mm/0.5mm slicethickness/intersection gap; axial Flair9000ms/140ms(TR/TE), 256 X 192matrix, 14 FOV, 1 NEX and a3mm/0.5mm slicethickness/intersection gap ;axial DWI EPI,10000ms/Min(TR/TE), 128 X 128matrix, 20 FOV, 1 NEX and a 3mm/0.5mm slicethickness/intersection gap. The volume of hematoma was calculated and features depicted.Histological Examinations: After the final examination ,each rabbit was sacrificed for histological examination.Fixed brains were cut coronally through the needle entry site ,as well as 2mm anterior and 2mm posterior to that plane. Brain slices were dehydrated and embedded in paraffin. Sections were cut and stained with FIE .patients: We investigated 36 patients with acute ICH between September 2004 and February 2005 ( 20 men, 16 women;age rang ,45-70years). All received both CT and MRI scans.Statistical analysis: Paired-sample t test was used to test the differencesof volume of hematoma between CT and MRI. With double-blind,two readers experienced in medical imaging were asked to review all sets of CT and MRI images, and evaluate the sensitivity of CT and MRI sequences.results and discussionHistopathological changes and corresponding MRI appearances were studied from 3h to 48h after injection. MR Images correlate well with histological changes in this experimental model of ICH. At 3h,T2WI showed faint hyperintensity ;DWI showed hypointensity in central area with hyperintense ring around hemorrhage; T2*WI showed hypointensity with a clear boundary. At 12h, there showed a little early degeneration of erythrocytes in the center. Around the periphery of the hematoma there scattered neutrophils and a few glial cells. At this period, T2WI showed only few areas of hyperintensity and a faint ring around hemorrhage. FLAIR sequence showed hypointensity in the center of hematoma with hyperintense ring. At 48h, there showed hyperintensity of hemorrhage in all sequences and microscopical examination showed many glial cells gathered around the hematoma .36 patients were examined with CT and MRI. The interval betweenthe studies was no more than 3 hours. We analysed the sensitivity of MRI in diagnosing hyperacute ICH on the b...
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