349 Brain Functional Imaging of Pain States Using Resting-State fMRI and Multi-Delay PCASL in Chronic Low-Back Pain Patients Implanted With Thoracic Spinal Cord Stimulation

Abstract

INTRODUCTION: A treatment of chronic low-back pain is implantation of a thoracic spinal cord stimulator (tSCS), which has been shown to reduce pain. The functional changes in pain processing regions of the brain as assessed by resting-state fMRI and multi-delay pseudocontinuous arterial spin labeling (PCASL) have never been studied. METHODS: PCASL data based on 5 post-label delays (0.5–2.5s) as well as rsfMRI were acquired in five patients (1F) post-tSCS with cLBP and five healthy subjects (2F). Patient MRI scans were taken post-implantation with the SCS device turned off. Three PCASL measures and four rsfMRI measures were derived and normalized into MNI space and smoothed. Averaged values for each measure from the pain ROI atlas were extracted and compared between patients and controls. Statistics were conducted following Box-Cox transformation of data. RESULTS: Arterial transit time derived from PCASL showed a significant difference in the OFC, SMA, and PSG of patients, but other ASL measures showed no effect. Several regions across the rs-fMRI measures showed significant differences, including those involved in cognition (DLPFC, PCC), and pain processing (PSG) and sensation (S2). CONCLUSIONS: Functional imaging showed that cLBP patients treated with SCS display differences in resting-state function and brain perfusion across several pain regions of the brain. These areas are mainly part of the cognitive and behavioral components of the pain circuitry.