Altered gray matter volume in patients with herpes zoster and postherpetic neuralgia

Jiaqi Liu,1,* Lili Gu,2,* Qing Huang,1 Shunda Hong,1 Xianjun Zeng,1 Daying Zhang,2 Fuqing Zhou,1 Jian Jiang1 1Department of Radiology, 2Department of Pain, The First Affiliated Hospital, Nanchang University, Nanchang, Jiangxi, People’s Republic of China *These authors contributed equally to this work Purpose: The aim of this study was to measure brain alterations in patients with herpes zoster (HZ) and postherpetic neuralgia (PHN) and compare their differences using a voxel-based morphometry (VBM) technique. Materials and methods: Thirty-three patients with HZ, 22 patients with PHN, and 28 well-matched healthy controls (HCs) were recruited. Magnetic resonance imaging data were acquired for all subjects and analyzed using the VBM method. The changes in gray matter volume (GMV) in HZ and PHN groups were compared with those in HC group, and the GMV differences were also compared between the PHN and HZ groups. Further correlation analysis and receiver operating characteristic curves were used to confirm the significance of GMV changes in various brain regions. Results: Compared with HCs, decreased GMV was found in the bilateral insular lobes and increased GMV was found in the bilateral thalamus in the HZ group. In the PHN group, GMV decreased in the bilateral insula lobes, right middle frontal gyrus, bilateral precentral gyrus, and left postcentral gyrus and increased in the left cerebellar posterior lobe, right parahippocampal gyrus, and right lentiform nucleus. In addition, the PHN group exhibited increased GMV in the left cerebellar tonsil, culmen, and left lentiform nucleus and decreased GMV in the right precentral gyrus compared with the HZ group. Further correlation analysis and receiver operating characteristic curves revalidate the significance of most of these abnormal brain regions. Conclusion: The VBM method revealed widespread GMV abnormalities in HZ and PHN patients. The brains of PHN patients have broader abnormalities in nonpain-related regions, suggesting the complexity of a central mechanism. When PHN patients were compared with HZ patients, the left cerebellar tonsil, culmen, and left lentiform nucleus corresponded to greater area under the curve, suggesting that abnormalities in these regions are risk factors for HZ patients’ transformation to PHN. Keywords: chronic pain, neuroimaging, ROC, fMRI, VBM