ABSTRACT
Objective To explore MRI characteristics of virus encephalitis and its relevance with pathlological changes,and to improve understanding MRI features of virus encephalitis.Methods Seventeen cases of virus encephalitis clinically proven were collected and reviewed.The correlation between MRI findigns and pathology were analyzed.MRI examinations included plain scan and FLAIR scan in all 17 patients,among which 13 underwent contrast-enhanced MR scanning.Results The lesions mainly located at the cerebral cortex gray matter and the cerebrum subcortical gray matter nuclei.16 cases appeared as multiple foci,and 1 case was single focus.The foci had definite margins and with no obvious peripheral edema.The lesions were slightly hypo-or iso-intense on T_1WI,slightly intensity on T_2WI and obvious high signal intensity on FLAIR.After enhanced scan,the lesions were no obvious enhancement in 2 cases,enhancement line in the surfaces of the brain in 15 cases,in which the lesions showed patch enhancement in 6 cases and gyrus-like enhancement in 2 cases.Conclusion The pathological changes of viral encephalitis can be reflexed with MR imaging features,which is of important value in the differential diagnosis of virus encephalitis.
ABSTRACT
Objective To explore the neural mechanism underlying the craving of heroin addicts induced by picture-cue and the correlation between the brain activation degree in nucleus accumbens (NAc)/the ventral striatum and the scores of patients' self-report craving. Methods Twelve active heroin addicts and 12 matched healthy controls underwent fMRI scan while viewing drug-related pictures and neutral pictures presented in a block design paradigm after anatomical scanning in GE 3.0 T scanner. The fMRI data were analyzed with SPM 5. The change of craving scores was tested by Wilcoxon signed rank test. The Pearson correlation between the activation of NAc/the ventral striatum and the heroin craving score was tested by SPSS 13.0. Results The craving scores of heroin addicts ranged from 0 to 3.70(median 0.15) before exposed to drug cue and 0 to 5.10(median 3.25) after viewing drug-related pictures and showed statistical significance(Z = -2.666, P < 0.05). There were 16 activated brain areas when heroin dependent patients exposed to visual drug-related cue vs. neutral visual stimuli. The activation brain regions belonged to two parts, one was limbic system (amygdale, hippocampus, putamen, anterior cingulate cortex and caudate), another was brain cortex (middle frontal cortex, inferior frontal cortex, precentral gyrus, middle temporal cortex, inferior temporal cortex, fusiform gyrus, precuneus and middle occipital gyrus). The MR signal activation magnitude of heroin addicts ranged from 0.19 to 3.50. The result displayed a significant positive correlation between the cue-induced fMRI activation in NAc/the ventral striatum and heroin craving severity (r=0.829, P < 0.05). Conclusion Heroin shared the same neural circuitry in part with other drugs of abuse for cue-induced craving, including brain reward circuitry, visualspatial attention circuit and working memory region. In addition, the dysfunction of NAc/the ventral striatum may attribute to heroin-related cue induced craving.
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Objective To study the value of~1H-magnetic resonance spectroscopy(~1H-MRS) and diffusion weighted imaging(DWI) in evaluating the changes of pathological structures of hippocampal sclerosis.Methods Twelve normal controls and twelve cases with temporal lobe epilepsy were examined by conventional MRI,~1H-MRS and DWI.The NAA/(Cr+Cho) ratios and ADC values in the hippocampus were measured and compared between patients and normal controls.Results The NAA/(Cr+Cho) ratios of hippocampus in patients with hippocampal sclerosis were significant decrease in comparison with controls and the contralateral side,and the ADC values were also significant increase.There was correlation between the NAA/(Cr+Cho) ratios and ADC values in the disordered hippocampus(r=-0.79,P=0.002).Conclusion There is a significant correlation between the NAA/(Cr+Cho) ratios and ADC values in the hippocampal sclerosis.~1H-MRS and DWI capture partially complementary aspects of hippocampal pathology noninvasively in vivo.