Prespective Study Of MRI And Cognitive Impairment For Patients With Suspected Herpes Simplex Encephalitis

Objectiv :To explore into the relationship between the magnetic resonance imaging (MRI) and the short-term efects of cognitive impairment in the patients with suspected herpes simplex encephalitis (HSE) and the characteristic of cognitive impairment.Methods : Based on prospective cohort study design ,ten suspected HSE cases in our hospital from December January 2008 to March 2010 and eight healthy individuals were randomly selected.The magnetic resonance imaging and the MMSE scales were adopted to assess the memory of all the subjects.Six patients with follow-up MR images,MMSE and the Wechsler Adult Memory scales that were obtained in 3 months and 6 months after the onset of HSE. We evaluated the signal changes, location of the lesions, and cognitive impairment.We also compared the hippocampal atrophy of the initial MR images to those of the follow-up MR images. The degree of hippocampal atrophy(DHA) was measured by the visual rating of the medial on MRI.Result : The MR images that were obtained within 7 days after the onset of HSE for two patients were normol,and that showed abnormal MR signal changes for ten patients. The characteristic location of lesions in temporal and frontal lobe were located in the cortical gray matter or subcortical white matter in nine patients and at the bilateral hippocampus in one. The FLAIR and T2-weighted MR images revealed focally increased signal intensity, swelling, and increased volume of the involved cortical gyrus in all eight patients while T1-weighted images showed decreased signal intensity at exactly the same location(n=9).The DHA that was obtained within 3 months after the onset of HSE was more obvious than onset,and the mental clarity and memory of the patients with suspected HSE were improved for 6 months on some extent.Compared with the healthy controls,the mean scores of MMSE in ten patients were significant (P<0.05) by independent-samples t test. The score of MMSE which obtained in 3 months after the onset of HSE compared to the 6 months were insignificant (P>0.05)by paired-samples t test. The MQ of the patients with suspected HSE was correlate with MMSE scales(P<0.05).The bilateral DHA and MQ were not related to MMSE scales(P>0.05), repectively.Conclusion: Routine MRI may be normal in the early time for the patients with suspected herpes simplex encephalitis. The characteristic location of lesions in temporal and frontal lobe were located in the cortical gray matter or subcortical white matter with the increased signal intensity of T2-weighted MR images and FLAIR, while T1-weighted images showed decreased signal intensity at exactly the same location. It was found that the hippocampal atrophy within 3 months was obvious and increased slowly within 6 months. The mental clarity and memory of the patients with suspected herpes simplex encephalitis were improved within 6 months.The MQ of six patients with suspected HSE was correlate with MMSE scales,but MMSE was less sensitive than WMS.The bilateral DHA and MQ were not related to MMSE scales, repectively.