| Patient with occlusion or severe stenosis of the cerebral artery without MRI evidence of brain parenchymal abnormalities is prone to suffer cerebral stroke, leukoaraiosis, encephalanalosis, vascular dementia. It is important to evaluate the damage of patient’s brain parenchymal with non-invasive imaging methods. In our study, the patients with normal appearing brain parenchymal and occlusion or severe stenosis of the unilateral middle cerebral artery (MCA) area were performed with perfusion-weighted imaging(PWI), diffusion tensor imaging (DTI) and magnetic resonance spectrum(MRS) use of a3T Tesla scanner(Ge Medical System, Excite Ⅱ,USA). The study was divided three chapter:CHAPTER Ⅰ application of perfusion-weighted imaging in unilateral cerebral arterial occlusive disease using3. OT MR, CHAPTER Ⅱ application of diffusion tensor imaging in unilateral cerebral arterial occlusive disease using3. OT MR, CHAPTER Ⅲ application of magnetic resonance spectrum in unilateral cerebral arterial occlusive disease using3.0T MR.CHAPTER Ⅰ Application of Perfusion-weighted Imaging in Unilateral Cerebral Arterial Occlusive Disease using3.0T MRABSTRACTPurpose:To assess perfusion changes in the areas brain parenchymal and remote white matter with unilateral occlusion or severe stenosis of the MCA without magnetic resonance imaging (MRI) evidence of brain parenchymal abnormalities using PWI.Materials and Methods:A total of34patients with occlusion or severe unilateral stenosis (≥75%) of the MCA without abnormal brain parenchymal signals underwent PWI at3T MR. The protocol was axial PWI with T2*-GRE-EPI. All brain imaging was conducted using a quadrature birdcage head coil. Contrast was Gd-DTPA with the dose of0.2mmol/kg and the rate of flow of4mml/s. PWI data were transferred to a workstation supplied by the manufacturer (Advantage Workstation4.2; GE Health-care) for further analysis. rCBF, rCBV, MTT and TTP were measured at ipsilateral (affected hemisphere) and contralateral (unaffected hemisphere) corona radiata, gray matter of temporal lobe, thalamus, lentiform nucleus, anterior and posterior limbs of the internal capsule and cerebral peduncle on the T2WI for all patients. Data analysis was conducted using SPSS13.0(SPSS, Chicago, IL, USA). Paired t-tests and rank test were used to compare mean rCBF, rCBV, MTT and TTP values. P<0.05was considered statistically significant.Results:The mean MTT and TTP were significantly higher, mean rCBF was significantly lower at ipsilateral corona radiata than at contralateral corona radiata (P<0.01), mean rCBV was not significantly different between the bilateral corona radiata. The mean MTT and TTP were significantly higher at gray matter of ipsilateral temporal lobe than at contralateral temporal lobe (P<0.01), mean rCBF and rCBV were not significantly different between the bilateral temporal lobe. The mean TTP was significantly higher at ipsilateral lentiform nucleus than at contralateral lentiform nucleus (P<0.01), mean MTT, rCBF and rCBV were not significantly different between the bilateral lentiform nucleus. The mean TTP was significantly higher at ipsilateral anterior and posterior limbs of the internal capsule than at contralateral anterior and posterior limbs of the internal capsule (P<0.01), mean MTT, rCBF and rCBV were not significantly different between the bilateral anterior and posterior limbs of the internal capsule. Mean MTT, rCBF, rCBV and TTP were not significantly different between the bilateral thalamus and bilateral cerebral peduncle.Conclusion:In conclusion, MTT, rCBF, rCBV and TTP may be used to sensitively depict perfusion changes in the brain parenchymal of regions of cerebral artery obstruction without abnormal perfusion in the remote white matter in patients with occlusion or severe stenosis of the MCA without MRI evidence of brain parenchymal abnormalities. Purpose:To assess diffusion changes in the brain parenchymal and remote brain parenchymal with unilateral severe stenosis or occlusion of the MCA without MRI evidence of brain parenchymal abnormalities using high b-value DTI.Materials and Methods:A total of34patients with severe occlusion or unilateral stenosis (≥75%) of the MCA without abnormal brain parenchymal signals underwent DTI at3.0T MR.The protocol was axial sensitivity-encoding echo-planar DTI with high b values (6000ms TR,90ms TE, four excitations),5mm section thickness,15non-collinear gradient directions; b=2200s/mm2. DTI data were transferred to a workstation supplied by the manufacturer (Advantage Workstation4.2; GE Health-care) for further analysis. FA, ADC, λ1and λ23were measured at ipsilateral (affected hemisphere) and contralateral (unaffected hemisphere) corona radiata, gray matter of frontal lobe, thalamus, lentiform nucleus, anterior and posterior limbs of the internal capsule, cerebral peduncle and pons on the T2WI (b=0) for all patients. Data analysis was conducted using SPSS13.0(SPSS, Chicago,IL, USA). Paired t-tests and rank test were used to compare mean FA, ADC, λ1and λ23values. P<0.05was considered statistically significant.Results:The mean FA was significantly lower (P<0.05), mean ADC, λ1and λ were significantly higher at ipsilateral corona radiata than at contralateral corona radiata (P<0.05).The mean λ23was significantly higher at ipsilateral gray matter of frontal lobe and lentiform nucleus than at contralateral frontal lobe and lentiform nucleus (P<0.05), mean FA,ADC and λ1were not significantly different between the bilateral gray matter of frontal lobe and bilateral lentiform nucleus. The mean FA was significantly lower, mean λ23was significantly higher at ipsilateral anterior and posterior limbs of the internal capsule than at contralateral anterior and posterior limbs of the internal capsule (P <0.05), mean ADC and λ1were not significantly different between the bilateral anterior and posterior limbs of the internal capsule. Mean FA, ADC, λ1and λ23were not significantly different between the bilateral thalamus, bilateral cerebral peduncle and bilateral pons.Conclusion:In conclusion, DTI may be used to sensitively depict diffusion changes in the brain parenchymal of regions of cerebral artery obstruction without abnormal anisotropy and diffusivity in the remote white matter in patients with occlusion or severe stenosis occlusion of the MCA without MRI evidence of brain parenchymal abnormalities. Purpose:To assess metabolism changes in the areas brain parenchymal with unilateral occlusion or severe stenosis of the MCA without MRI evidence of brain parenchymal abnormalities using MRS.Materals and Methods:A total of34patients with occlusion or severe unilateral stenosis (≥75%) of the MCA without abnormal brain parenchymal signals underwent MRS at3.0T MR. The protocol was chemical shift imaging (CSI) MRS with multi voxel acquisition and point resolved spectroscopy (PRESS)(1500ms TR,135ms TE),5mm section thickness,5.6min scan time. MRS data were transferred to a workstation supplied by the manufacturer (Advantage Workstation4.2; GE Health-care) for further analysis. NAA, Cr, Cho, NAA/Cho, NAA/Cr, Cho/Cr and were Lac measured at ipsilateral (affected hemisphere) and contralateral (unaffected hemisphere) corona radiata, thalamus and lentiform nucleus on the T2WI for all patients. Data analysis was conducted using SPSS13.0(SPSS, Chicago, IL, USA). Paired t-tests and rank test were used to compare NAA, Cr, Cho, NAA/Cho, NAA/Cr and Cho/Cr. P<0.05was considered statistically significant.Results:The mean NAA, Cr, NAA/Cr and NAA/Cho were significantly lower, mean Cho, Cho/Cr were significantly higher at ipsilateral corona radiata than at contralateral corona radiata (P<0.05). Mean Cho, NAA, Cr, NAA/Cr, NAA/Cho and Cho/Cr were not significantly different between the bilateral thalamus. The mean NAA and NAA/Cho were significantly lower, mean Cho and Cho/Cr were significantly higher at ipsilateral lentiform nucleus than at contralateral lentiform nucleus (P<0.05),while Cr and NAA/Cr were not significantly different between the bilateral lentiform nucleus, Lac was not found at ipsilateral corona radiata, thalamus and lentiform nucleus of these patients.Conclusion:In conclusion, MRS may be used to sensitively depict metabolism changes in the brain parenchymal of regions of cerebral artery obstruction in patients with occlusion or severe stenosis of the MCA without MRI evidence of brain parenchymal abnormalities. |
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