Assessing osteoporosis and bone mineral density through ¹⁸F-NaF uptake at lumbar spine

The use of ¹⁸F-Sodium fluoride (NaF) PET/CT is established in the detection of metastatic bone disease, yet its utility in osteoporosis remains underexplored. This research aims to assess the variations in ¹⁸F-NaF uptake among individuals with differing bone mineral density (BMD) and to examine the relationship between ¹⁸F-NaF uptake and BMD.

In this retrospective study, 199 patients (average age 56 ± 6, comprising 52 males and 147 females) with a history of cancer were analyzed. Each participant underwent both ¹⁸F-NaF PET/CT and lumbar dual-energy X-ray absorptiometry (DXA) scans within a span of 7 days. Based on DXA outcomes, patients and their lumbar vertebrae were categorized into normal BMD, osteopenia, and osteoporosis groups. The lumbar ¹⁸F-NaF uptake across these groups were compared, and to explore the association between lumbar standardized uptake values (SUV) values and BMD. The efficacy of ¹⁸F-NaF uptake in diagnosing osteoporosis or osteopenia was also evaluated. Analysis was conducted using Mann-Whitney U tests, Spearman regression, and receiver operating characteristic (ROC) curve analysis through GraphPad Prism 10.0.

A total of 796 lumbar vertebrae from 199 patients were measured. It was observed that osteoporotic patients had significantly lower ¹⁸F-NaF uptake than those with osteopenia and normal BMD across the L1-L4 lumbar vertebrae (P < 0.0001). In a vertebra-based analysis, normal BMD vertebrae exhibited the highest maximum SUV(SUV_max) compared to osteopenic (8.13 ± 1.28 vs. 6.61 ± 1.01, P < 0.0001) and osteoporotic vertebrae (8.13 ± 1.28 vs. 4.82 ± 1.01, P < 0.0001). There was a positive correlation between lumbar ¹⁸F-NaF uptake and BMD across all vertebrae, with correlation coefficients exceeding 0.5 (range: 0.57-0.8). The area under the ROC curve values were notably high, at 0.96 for osteoporosis and 0.83 for osteopenia diagnosis.

This study demonstrates distinct ¹⁸F-NaF uptake patterns among individuals with varying BMD levels, with a positive correlation between ¹⁸F-NaF uptake and BMD. These findings highlight the potential of ¹⁸F-NaF PET/CT as a supportive diagnostic method in the management of osteoporosis.