Comparative Study On Japanese Encephalitis In Adults And Children Using Early Diffusion Weighted Imaging

Objectives:This study examines the imaging characteristics of adult and childrenJapanese encephalitis (JE) in conventional MRI (sequential T1WI, T2WI and FLAIR)and early diffusion weighted imaging (DWI).1. MRI image differences between adultsand children are first discussed;2. The capabilities of lesion identification forconventional scans and early DWI are investigated through detailed comparisons.Method:The subjects of the study are59JE cases collected between2006and2013at First Affiliated Hospital of Henan University of Science and Technology. In allcases, patients were confirmed with JE by the positive results of ELISA onCerebrospinal fluid (CSF)/serum IgM. The diagnostic imaging for all the59patientsthat are divided into two groups-32adults (>16years old) and27children (<16y. o.)respectively-was conducted by a GE Signa Twinspeed1.5T MRI scanner. All patientsexperienced T1WI, T2WI and FLAIR sequential scans.23adult patients and20children received DWI within7days after neural symptoms had been observed. Basedon the observations, MRI characteristics for adults and children with JE have beenextracted; and the capability variance of lesion identification for conventional scansand early DWI are analyzed.Results:1. Of the32adult patients experienced MRI scanning,28were positive and4negative, respectively. The JE lesions were associated with thalamus in22cases;substantia nigra of midbrain in13cases; Kellogg’s seahorse in9cases; basal ganglia in7cases; splenium corporis callosi in4cases; Pons in3; insular lobe in2, and extensivecerebral edema in2cases, respectively. Of the23adults experienced early DWI,3cases showed cytotoxic edema;12cases involved vasogenic edema;5patientsdemonstrated both types of edemas; and3patients were normal.2. In the childrengroup of27patients,25were positive and2negative in MRI scans. The lesions of JEoccurred in thalamus in24cases; substantia nigra of midbrain in13; cortical andsubcortical in6; basal ganglia in4; Kellogg’s seahorse2; and splenium corporis callosiin2, respectively. Twenty (20) children patients experienced early DWI. Ofthem8showed cytotoxic edema;7vasogenic edema; and3children showedcoexistence of both edemas. Two patients demonstrated normal in the DWI.3.Comparisons of the lesion-prone spots between adults and children have beenconducted. In69%of adults and89%of children, JE virus is prone to be found inthalamus, indicating no statistic difference. In22%of the children, JE virus is found topartially affect cortical and subcortical tissues; whereas for adult, no impact isobserved.4. Comparisons of early DWI results between adults and children are alsomade. The results show that adult JE is associated with cytotoxic edema in3cases;vasogenic edema in12; coexistence of both edemas in5cases. Meanwhile, inchildren’s group, the corresponding numbers are8,7and5, respectively. Between thetwo groups, there were statistic variances in the ratio of edemas (P<0.05). Particularlythe ratio of cytotoxic edemas was much higher among children.5. The comparisons oflesion identification capabilities for conventional scan and early DWI are as follows.Among38patients, consisting of both adults and children, who received both earlyDWI and T2WI/FLAIR, it was found that early DWI apparently demonstrated betterthan FLAIR and T2WI in11cases where lesions occurred in cytotoxic edema. Of the19cases where lesions were observed in vasogenic edema, in16cases, T2WI andFLAIR were superior to DWI, of which in7cases, DWI demonstrated pseudo-normalcharacteristics and failed to detect lesions. In3cases, DWI was advantageous overconventional approaches. In the other8cases, cytotoxic and vasogenic edemascoexisted.Conclusion:1. JE virus is prone to be found in thalamus for both adults andchildren. There is no statistical difference in the location and distribution of the virusin the thalamus in both groups; compared with that of adults, children JE virus is moreassociated with cortical and subcortical tissues.2. In early DWI, adults and childrenstatistically demonstrate different ratios of cytotoxic and vasogenic edemas. Moreover,it’s found that cytotoxic edemas is more representative for children.3. When JElesions show as cytotoxic edemas, DWI is evidently advantageous over T2WI, FLAIRin lesion detection. Whereas in detection of vasogenic edema representing lesions,normally T2WI, FLAIR are more reliable than early DWI.