Serial Imaging Studies Of Hemorrhagic Transformation After Cerebral Infarction

Part 1 The comparative imaging study of hemorrhagic transformation after cerebral infarctionObjective:To investigate the characteristics of hemorrhagic transformation after cerebral infarction (HT) on CT and MRI and a comparison of the two.Methods: Retrospective analysis of the CT and MRI images of 60 cases with HT were performed.According to the European cooperative of acute stroke study (ECASS) classification, CT classification was made, and on this basis, the new MRI classification of HT was conducted combined with characteristics of this group, and a comparative study of features on CT and MRI was done.Results: Based on the MRI image, HT could be divided into 2 types:①HI(no hematoma): HI-1, the small punctate hemorrhage along the edge of infarction;HI-2,hemorrhage without mass effect in infarct region.②PH (hematoma formation): PH-1, light mass effect, less than 30% infarct size;PH-2, Hematoma of more than 30% infarct size, apparent mass effect, and hemorrhage far from the infarct area. In this study, the two types based on CT and MRI were shown differently. Classification based on CT was as follows: HT 15 cases (25.0%). HI, 7 cases (11.7%), HI-1 type 2 cases, HI-2 type 5 cases. PH, 8 cases (13.3%), PH-1 type 3 cases, PH-2 type 5 cases. Classification based on MRI was the following: HT 60 cases (100%). HI, 52 cases (86.7%), HI-1 type 25 cases, HI-2 type 27 cases, 2 cases of them, at the same time, with HI-1 and HI-2 type performance, were classified as HI-2 type. PH, 8 cases (13.3%), PH-1 type 3 cases, PH-2 type 5 cases.The density and signal characteristics of HT: On CT heamorrhage was shown with high density, and it was difficult to find chronic phase and micro bleeding. On MRI, T1WI: In super-acute phase, acute phase, chronic phase, heamorrhage was mainly performed with low or equal signal, while in sub-acute phase with high signal mostly. T2WI and FLAIR: In super-acute phase, acute phase, early subacute was mainly performed with low signal, while late subacute sub-acute phase and chronic phase with high signal mostly.Location and shape of HT: CT showed 15 cases of HT: 1 case was under the tentorium of cerebellum (1.7%), located in the cerebellum, PH-2 type. 14 cases (23.3%) were above the tentorium of cerebellum, HI-1 type 2 cases, HI-2 Type 5 cases, PH-1 type 3 cases, PH-2 type 4 cases. MRI showed 60 cases of HT: 9 cases under tentorium of cerebellum (15.0%), 6 cases in cerebellar, 2 cases in brain stem, 1 case with both cerebellar and brain stem at the same time. 1 case for the PH-2 type (11.1%). The remaining 8 cases were classified as the HI-1 type. 51 cases (85.0%)were above the tentorium of cerebellum, PH-type 7 cases (13.7%), PH-1 type 3 cases, PH-2 Type 4 cases. The shape of heamorrhage: For the HI: CT demonstrated patchy and irregular line-like; MRI was"brain-like", irregular patchy and line-like. The size and number of the HT showed on CT were less than on MRI. For PH: both were expressed as mass, but the size and scope showed on MRI were larger than on CT.Conclusion: Two typing methods draw different conclusions. MRI diagnosis for HT is more sensitive than CT. MRI can show chronic phase or microbleeding that CT can not find. In displaying the sub-acute stage and under the tentorium of cerebellum hemorrhage MRI is better than CT. The shapes of HT in the same cases may be different between CT and MRI classification.The number, size and scope showed on MRI are larger than on CT,and the MRI classification of HT may also be senior. MRI classification of HT will be helpful in guiding clinical treatment and prognosis.Part 2 The clinical application value of Susceptibility Weighted Imaging for hemorrhagic infarction after ischemic strokeObjective: To evaluate the clinical application value of susceptibility weighted imaging (SWI) for hemorrhagic infarction after ischemic stroke (HI). Method: 13 cases with HI were examined with 3.0T MR.Conventional MRI sequences and SWI were performed, T2*WI, MRA, MRV or MRS were performed partly meanwhile, and then the SWI image was compared with the conventional MRI images and T2*WI image. Raw data of SWI was sent to GE Advantage workstation 4.2 workshop and corrected phase image and Negative Mask images were reconstructed automatically, and maximum intensity projection was performed,and then the Min map was acquired.Results: Gray matter and white matter showed on SWI were comparatively clear, which was similar to T2FLAIR image. SWI was better than conventional MRI images and T2*WI in displaying the number and scope of hemorrhage, it could also detect the mico-lesion which was hard to find on the conventional MRI images and T2*WI image. In detecting HI, SWI was superior to the conventional MRI sequences and SWI. Min map could clearly display the veins, which had strip like branches of different size with hypointensive. Min: cerebral veins disappeared in hemorrhagic zone. In infarction zone cerebral veins were decreased in 8 cases (obviously decreased in 3 cases), increased in 1 case. 5 cases showed cerebral veins dilation around infarction zone. 1case showed artery clots with strip hypointensive.Conclusion: In detecting HI, SWI is better than conventional MRI sequences and T2*WI. SWI has some advantages in displaying the artery clots. It can display not only the ischemic lesion, but also the vascular in and around the ischemic lesion, so it is helpful to locate the area of the injured vacular and to make sure the involved scope of ischemic. SWI has vital values in the diagnosing of HI,monitoring hemorrhagic transformation after ischemic stroke and is helpful to choose clinical treatment, especially to potentially judge the cerebral hemodynamics, the viability of brain and prognosis.Part 3 The clinical application value of SWI quantitative research for hemorrhagic infarctionObjective: To evaluate the clinical application value of the corrected phase value(CPV) of 3.0T MR susceptibility weighted imaging (SWI) in HI, and set a new direction for its diagnosis and differential diagnosis.Method: 10 patients(7 male, 3 female) diagnosed as HI were selected from the Second Hospital of Hebei Medical University between January 2007 and October 2008 as case group, the mean age of the subject population was 44.30±10.16 years with a range of 28～60 years. 14 healthy volunteers (5 male, 9 female) were selected as control group, the mean age was 40.14±18.72 years with a range of 14～62 years.There was no significant difference between the two groups in age.All subjects in the case group and in control group were examined by the conventional MRI sequences and SWI. Raw data of SWI was sent to GE Advantage workstation 4.2 workshop and the corrected phase image were reconstructed automatically.①The conventional MRI images and the corrected phase image of SWI of the control group and the case group were observe and analyzed.②The CPV of ROI on the corrected phase image was measured. In the case group, the ROI of the heamorrhage area and the mirror area were measured,while in the case group the ROI of the globus pallidus, putamen and caudate nucleus were measured.③The CPV of the haemorrhage area and the mirror area in basal ganglia in the case group was analyzed comparatively.④The mean CPV of the heamorrhage area in basal ganglia in the case group and the corresponding area in the control group was analyzed comparatively.Statistical analysis was performed.Results:①The conventional MRI images and SWI images of the control group were normal. Basal ganglia showed a negative phase, the edge of which was positive phase. Higher iron content of brain regions showed on the SWI image was more clearly than on the conventional MRI images. All the heamorrhage in the case group was shown on the corrected phase image of SWI. The shape was patchy and the signal was significantly lower than the surrounding tissue and the contralateral normal basal ganglia.②In the case group, the difference of the CPV between the haemorrhage area and the mirror area in the case group was significant.③The CPV of the heamorrhage area in each part of basal ganglia in the case group was lower than that in the correspongding parts in the control group. Moreover, the difference of the putamen had statistical significance.Conclusion: The corrected phase map can display clearly each part of basal ganglia which has different iron content. The decrease of the CPV of the heamorrhage area in HI might be helpfull in diagnosis, differential diagnosis and treatment . of the hemorrhagic diseases.Part 4 The clinical application value of 3.0T MR SWI for intracerebral microbleeds in strokeObjective: To evaluate the clinical application value of susceptibility weighted imaging (SWI) for intracerebral microbleeds (IMBs) in patients with stroke and compare the detection capabilities of IMBs among SWI, T2*WI and the conventional MRI sequences.Methods: 19 cases who were admitted to hospital due to stroke with IMBs were examined by 3.0T MR. Conventional MRI sequences and SWI were performed in all. T2*WI were performed in 17 cases.①The frequency of IMBs in different stroke patients was observed.②The differences among SWI, T2*WI and the conventional MRI sequences in signal characteristics, number, regional distribution, size and shape were compared.③The correlation of the severity of the number of IMBs and lacunar infarcts was analyzed.Results:①Multiple lacunar infarcts was more common in IMBs(84.2%). IMBs were more prone to be complicated by cerebral hemorrhage than common cerebral infarction.②SWI was more sensitive to IMBs than T2*WI and the conventional MRI sequences. The most common locations of IMBs in patients with stroke were basal ganglia, thalami and cortico-subcortical region.③There was a correlation between the number of IMBs and lacunar infarcts.Conclusion: The exact diagnosis of IMBs could be made by SWI. SWI is more sensitive to IMBs than T2*WI and the conventional MRI sequences. The existense of multiple IMBs in patients with stroke might be an indicator of severity of microangiopathy and an increasing risk for bleeding, and these patients are easy to be complicated by cerebral hemorrhage or HT after the anticoagulation and thrombolytic therapy, which should be taken into consideration in the treatment options and prognosis of patients.Part 5: MRI image characterization and clinical analysis of hemorrhagic infarctionObjective: To assess the MRI image characterization of hemorrhagic infarction (HI) and its relationship with clinical manifestations.Methods: The MRI manifestations and clinical data of 30 patients diagnosed as HI were selected from the Second Hospital of Hebei Medical University between July 2007 and June 2008. The images were analyzed by two neuroradiologists. The shape, location, scope and signal of the lesion were analyzed. Whether there were risk factors of HI, changes of clinic magnifestation, when HI was discovered, the treatment option and prognosis were followed.Results: Clinic material: Hypertension was the most common risk factor of HI, about 60%, the second was Diabetes (23.3%), the third was coronary heart disease (23.3%), and the fourth was atrial fibrillation (20%). HI often appeared in 2 weeks after cerebral infarction, about 76.7%.HI was discovered after the performation of MRI examination for the purpose of a comfirmed diagnosis or a review after the treatment in 27 cases. 3 cases performed MRI examination for the deterioration of clinic symptoms. In the cases followed-up, the symptoms and signs of nervous system were improved in 29 cases.Medical imaging data: The shape and location of hemorrhage were different in HI patients with different positions of infarction.In 15 patients (50.0%) the HI was limited in brain lobes, hemorrhage was located in cortex and/or subcortical white matter with patch border or brain gyrus like In 10 patients (33.3%) HI was limited in deep part of brain (the basal ganglia and thalamus)and in 4 patients (13.3%) HI was limited in cerebellum, hemorrhage was in inner or boundary with patch border or line-like. In 1 patient (3.4%) HI involved brain lobe and deep part. HI was shown as low signal on T2*WI.Conclusion: There are typical manifestations of MRI in HI, and it is closely related with the position and area of cerebral infarction. If patient's condition becomes more serious or large area infarction is considered, CT/MRI should be reviewed in 2 weeks for the early diagnosis and treatment of HI.