LAUSR

BACKGROUND Current imaging modalities are often incapable of identifying nociceptive sources of low back pain (LBP). We aimed to characterize these by means of positron emission tomography/computed tomography (PET/CT) of the lumbar spine region applying tracers 18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) targeting inflammation and active microcalcification, respectively. METHODS Using artificial intelligence (AI)-based quantification, we compared PET findings in two sex- and age-matched groups, a case group of 7 males and 5 females, mean age 45±14 years, with ongoing LBP and a similar control group of 12 pain-free individuals. PET/CT scans were segmented into three distinct volumes of interest (VOIs): lumbar vertebral bodies, facet joints, and intervertebral discs. Maximum, mean, and total standardized uptake values (SUVmax, SUVmean, and SUVtotal) for FDG and NaF uptake in the 3 VOIs were measured and compared between groups. Holm-Bonferroni correction was applied to adjust for multiple testing. RESULTS FDG uptake was slightly higher in most locations of the LBP group including higher SUVmean in the intervertebral discs (0.96±0.34 vs. 0.69±0.15). All NaF uptake values were higher in cases, including higher SUVmax in the intervertebral discs (11.63±3.29 vs. 9.45±1.32) and facet joints (14.98±6.55 vs. 10.60±2.97). CONCLUSION Observed inter-group differences suggest acute inflammation and microcalcification as possible nociceptive causes of LBP. AI-based quantification of relevant lumbar VOIs in PET/CT scans of LBP patients and controls appears to be feasible. These promising, early findings warrant further investigation and confirmation. This article is protected by copyright. All rights reserved.