The First Long Term Objective Quantification of Multifidus Activity during Restorative Stimulation - 18fdg-Pet-Ct Assessment of Multifidus Activity and Radiomics Based Heterogeneity Analysis

Abstract

Introduction: Restorative neurostimulation for chronic mechanical low back pain relies on stimulation of the L2 medial branch of the dorsal ramus to elicit episodic tetanic contractions of the lumbar multifidus muscle. Long term clinical, 4 year data supports the improvement in pain and quality of life indices.1,2 This is now the first quantification of metabolic activity, heterogeneity using PET uptake measurements and radiomic based texture analysis on 18F FDG-PET/CT that provides a unique opportunity to visualize and quantify changes in the segmental and entire lumbo-sacral length of multifidus and paraspinal muscles in response to restorative neurostimulation therapy. Materials / Methods: After regulatory approval (Clin Trials Gov NCT04327817 and Rec 20/LO/0740) 7 patients underwent three 18F FDG-PET/CT at baseline, 6 months and 1 year following multifidus stimulator implant. 18F-FDG-PET CT was acquired on GE-Discovery 710 PET system with a 128 slice CT (approx. 250 MBq i.v). Baseline scan was performed with patients at rest while the six-month and 12 month scan was obtained immediately after a 30 minute multifidus stimulation session. Metabolic activity within the brain and multifidus was quantified using maximum standardized uptake value (SUVmax). Low dose CT texture analysis (CTTA) of the multifidus muscle was performed to examine changes in heterogeneity within the multifidus muscles (using entropy as a parameter reflecting irregularity at pixel resolution).