PT - JOURNAL ARTICLE AU - Noguchi, T. AU - Mihara, F. AU - Yoshiura, T. AU - Togao, O. AU - Atsumi, K. AU - Matsuura, T. AU - Kuroiwa, T. AU - Honda, H. TI - MR Imaging of Human Herpesvirus-6 Encephalopathy after Hematopoietic Stem Cell Transplantation in Adults DP - 2006 Nov 01 TA - American Journal of Neuroradiology PG - 2191--2195 VI - 27 IP - 10 4099 - http://www.ajnr.org/content/27/10/2191.short 4100 - http://www.ajnr.org/content/27/10/2191.full SO - Am. J. Neuroradiol.2006 Nov 01; 27 AB - BACKGROUND AND PURPOSE: Human herpesvirus-6 (HHV-6)-associated encephalopathy tends to develop in immunocompromised patients. Neurologic symptoms, such as disorientation, short-term memory loss, convulsion, coma, and hypopnea could occur, but they may be nonspecific. We retrospectively reviewed MR images of 6 adults with HHV-6-associated encephalopathy to study characteristic imaging findings that could be useful in making the diagnosis.MATERIALS AND METHODS: Between 2003 and 2005, we encountered 6 cases of HHV-6-associated encephalopathy (3 men and 3 women; age range, 36–55 years) in 3 hospitals. The diagnosis was made clinically according to the neurologic symptoms accompanied by high-level copies of HHV-6 DNA in CSF or peripheral blood by quantitative polymerase chain reaction without the detection of any other infectious pathogen.RESULTS: All 6 patients had abnormal hippocampus/amygdala findings on presentation, and no other regions were involved. In the early period (0–2 days from onset), abnormal high signal intensity on fluid-attenuated inversion recovery (FLAIR) imaging (2 of 3, 67%) and on diffusion-weighted images accompanied by apparent diffusion coefficient (ADC) reduction (2 of 2, 100%) were observed. In the middle period (3–30 days), abnormal low signal intensity on T1-weighted images (5 of 6, 83%) and abnormal high signal intensity on T2-weighted images (4 of 6, 67%) and FLAIR (5 of 6, 83%) were confirmed. In the late period (> 30 days), we saw the resolution of signal intensity abnormalities and the appearance of atrophic change (4 of 4, 100%) of the affected regions.CONCLUSION: HHV-6-associated encephalopathy in adults tends to affect the mesial temporal lobe. MR imaging is useful for detecting HHV-6 encephalopathy and distinguishing it from the other diseases of the central nervous system in immunocompromised patients.