A combined DTI and resting state functional MRI study in patients with postherpetic neuralgia

Abstract

Purpose: To explore the brain microstructural and functional changes in patients with postherpetic neuralgia (PHN).

Materials and methods: 12 PHN patients and 12 healthy volunteers were enrolled. Diffusion tensor imaging (DTI) and resting-state functional MRI (rfMRI) sequences were scanned by a 3T MR scanner. Fractional anisotropy (FA) and mean diffusivity (MD) t-maps were obtained following DTI data processing. The amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) were obtained following rfMRI data processing. A two sample t-test was performed to compare the FA, MD, ALFF and fALFF differences between the PHN patients and healthy controls.

Results: No significant differences were noted with regard to the parameters gender, age and education years between the two groups. FA, MD, ALFF and/or fALFF indicated significant alterations in specific pain or pain-related brain regions, such as brainstem, cerebellum, parietal lobe, precuneus, frontal lobe, temporal lobe, postcentral and precentral gyrus, corpus callosum, cingulate gyrus, putamen and insula.

Conclusion: Multi-local alterations of spontaneous brain activity could form a network related to chronic pain, sensory discrimination, emotion and cognition, suggesting complicated central mechanisms of PHN. The combined-action of brain microstructure and function may play a critical role in comprehension of neurological mechanisms of PHN-induced pain.

Keywords: ALFF; DTI; PHN; VBA; rfMRI.