Multiple Sclerosis, Magnetic Resonance Imaging Study

ObjectiveTo establish rats model of experimental allergic encephalomyelitis for further study of multiple sclerosis.Methods44 female Lewis rats were randomly divided into experimental allergic encephalomyelitis group(27) and control group(17).The experimental allergic encephalomyelitis model was established by immunization with guinea pig cerebrospinal homogenate and Complete Freund's adjuvant.The control group rats were injected normal saline and Complete Freund's adjuvant.The change of weight and clinical symptom of both groups rats were observed everyday.The samples of brain tissue in both group rats were taken at different time points.Hematoxylin and Eosin(HE) staining and myelin staining were performed.Inflammatory cells infiltration and demyelination were observed under light microscope.ResultsThe clinical symptoms appeared in experimental allergic encephalomyelitis group rats from 15 to 30 day after immunization.The incidence was 22/27.The infiltration of inflammatory cells and demyelination of brain tissue in experimental allergic encephalomyelitis rats were observed histopathologically.No clinical symptoms appeared and no histopathological abnormality were observed in control rats.ConclusionThe animal model of experimental allergic encephalomyelitis was successfully established with guinea pig cerebrospinal homogenate in Lewis rats.The model is stable and high in incidence and can be used to study multiple sclerosis. ObjectiveTo explore the sensitivity of magnetic resonance contrast agent ultrasmall superparamagnetic iron oxide(USPIO) enhancement scan in detecting experimental allergic encephalomyelitis lesions and the change of magnetization transfer of USPIO enhancement lesions in the animal model of experimental allergic encephalomyelitis (EAE).MethodsThe routine T1-weighted imaging,T2-weighted imaging,three dimensional T1 magnetization transfer,three dimensional T1 No magnetization transfer,Gd-DTPA (Gadopentetate Dimeglumine Injection) enhancement,and USPIO enhancement scan were performed in 11 EAE rats and 10 control rats respectively.The sensitivity of USPIO and Gd-DTPA enhancement in detecting the lesions in EAE rats was calculated. Magnetization transfer ratio(MTR) of USPIO enhancement area for the first time in EAE rats and MTR of the same area of the last scan were calculated respectively.HE, myelin and prussian Fe staining of brain tissues were performed.ResultsNo abnormally enhanced lesions were showed in EAE rats' brain in Gd-DTPA enhancement scan,while abnormally enhanced lesions were showed in 11 EAE rats' brain in USPIO enhancement scan.The MTR value of USPIO enhancement area for the first time was significantly different from MTR of the same area of the last scan in EAE rats(P<0.05).Inflammation cells and demyelination lesions were found in USPIO enhancement area histopathologically.The result of prussian Fe staining were positive. There were no positive findings in control rats.ConclusionThe sensitivity of USPIO enhancement scan in detecting EAE lesions was high.MT imaging,together with USPIO enhancement scan,was helpful to determine the features of the EAE lesions. ObjectiveTo compare the sensitivity of double inversion recovery with fluid-attenuated inversion recovery and T2-weighted Fast Spin Echo imaging in detecting multiple sclerosis lesions.MethodsMR examination including DIR,FLAIR and T2 FSE sequences was performed in 13 patients with MS(11 females,2 males,age ranged from 20 to 62 years,average age 36 years) and 13 age and gender-matched healthy volunteers(11 females,2 males,age ranged from 22 to 60 years,average age 36 years).Lesions were categorized on the basis of 7 anatomic regions:intracortical,juxtacortical,deep gray matter,mixed white-gray matter,periventricular white matter,deep white matter and infratentorial brain tissue and the number of lesions was calculated accordingly.The numbers of lesions detected by DIR in different regions was compared with those detected by FLAIR and T2 FSE sequences.The contrasts between lesions and normal-appearing gray matter, normal-appearing white matter and CSF in patient group were measured in 3 sequences respectively.The statistical differences were assessed using the t test for matched pairs.P values < 0.05 were considered as statistically significant.ResultsThe total numbers of lesions shown by DIR,FLAIR and T2 FSE were 709,627 and 535 respectively.There were gains of 82 and 174 in DIR compared with the FLAIR(P= 0.003)and T2 FSE(P=0.001) respectively.DIR depicted 58 infratentorial lesions, increasing 48 and 20 compared with the FLAIR(P=0.001) and T2 FSE(P=0.140).In the supratentorial brain,DIR detected 82 intracortical lesions,4 juxtacortical lesions,151 mixed gray-white matter lesions,103 periventricular lesions,9 deep gray matter lesions and 302 deep white matter lesions.There were gains of 67(P=0.004),-225(P=0.031), 149(P=0.022),-41(P=0.176),-16(P=0.251),100(P=0.292) than FLAIR and 82(P =0.002),-119(P=0.104),141(P=0.019),15(P=0.092),-11(P=0.497),46(P=0.419) than T2 FSE accordingly.The contrasts between lesions and normal-appearing gray matter and between lesions and normal-appearing white matter in DIR were higher than FLAIR(P=0.000;P=0.000).The contrast between lesions and CSF in DIR was lower than FLAIR(P=0.109).The contrasts between lesions and normal-appearing white matter and between lesions and CSF in DIR were higher than T2 FSE(P=0.000;P= 0.000).The contrast between lesions and normal-appearing gray matter in DIR was lower than T2 FSE(P=0.145).ConclusionDIR was able to increase the detection of infratentorial and intracortical lesions and improved categorization of intracortical,juxtacortical and mixed white-gray matter lesions.With higher lesions contrast ratio,DIR was more sensitive MR sequence in detecting MS lesions in brain. ObjectivesTo investigate the change of fractional anisotropy values of brain in patients with multiple sclerosis.Methods13 patients with MS(11 females,2 males,age ranged from 20 to 62 years,average age 36 years) and 13 age and gender-matched controls(11 females,2 males,age ranged from 22 to 60 years,average age 36 years) without nervous system disease were studied. Conventional MR imaging protocols and diffusion tensor imaging were performed.The regions of interest were placed on the plaques,peri-plaque regions,normal-appearing white matter around the plaques in MS patients and in white matter around lateral ventricle in control group.The FA values of both MS patients and the controls were measured.The regions of interest were placed on four different portions of the normal-appearing corpus callosum,namely genu,anterior and posterior portion of the body and splenium in both groups.The FA values of both MS patients and the controls were measured respectively.The statistical analysis was performed with independent sample t test and p<0.05 was considered significant statistically.ResultsThe average FA value of 42 plaques,peri-plaque regions and NAWM in MS patients was 0.21,0.35 and 0.49 respectively.The average FA value of white matter of control was 0.61.There were significant differences of FA values in plaques(p=0.000), peri-plaque regions(p=0.000),NAWM near the plaques(p=0.000) compared with the white matter in the control group.The FA values in the genu(0.65±0.05),anterior body(0.48±0.03),posterior body (0.52±0.03) and splenium of corpus callosum(0.73±0.05) were lower in the MS patients in comparison with the FA value(0.75±0.04,0.71±0.05,0.74±0.04,0.80±0.03) in corresponding areas of corpus callosum in controls(p=0.000,0.000,0.000,0.000,respectively). ConclusionDTI could show the occult injury of the NAWM and normal-appearing corpus callosum of MS patients in the early phase of disease and was considered more effective than conventional MR imaging sequences in studying MS patients.