The following is the summary of “MRI-Based Score for Assessment of Bone Mineral Density in Operative Spine Patients” published in the January 2023 issue of Spine by Kim, et al.
Introspective evaluation. The purpose of this study was to validate a previously developed bone mineral density (BMD) grading system based on magnetic resonance imaging (MRI) and to see if it can distinguish between healthy and osteoporotic vertebrae. When planning spinal surgery, BMD must be taken into account. Measurements of BMD can be inaccurate due to spondylosis (dual-energy X-ray absorptiometry) or highly radiation-intensive (quantitative computed tomography) in some cases. In the past, researchers have found that variations in the bone marrow signal on T1-weighted MRIs can be used as an indicator of bone quality.
Study of lumbar surgery patients treated between 2016 and 2021 (n=61) using a retrospective design. Vertebral bone quality (VBQ) scores were calculated by dividing the median signal intensities of L1–L4 by the cerebrospinal fluid signal intensity on non-contrast T1W MRI. Analysis of variance with post hoc Tukey test compared demographics, comorbidities, VBQ scores, Quantitative computed tomography (QCT)-derived T scores and lumbar spine BMD between healthy (T score 1; n=21), osteopenic (2.5 T score 1; n=21), and osteoporotic (T score 2.5; n=19) populations. The predictive value of VBQ scores was analyzed using linear regression and receiver operating characteristic curves. The relationship between VBQ ratings and QCT-derived parameters was analyzed using the Pearson correlation test.
It was found that VBQ could distinguish between healthy and osteoporotic individuals (P=0.009). The presence of osteoporosis was found to be correlated with higher VBQ scores (area under the curve=0.754, P=0.006), as determined by receiver operating characteristic curve analysis. Cutoff VBQ for osteoporosis was 2.6 (Youden index 0.484; sensitivity: 58%; specificity: 90%). There was a somewhat weak relationship between VBQ scores and BMD (P=0.03, r=0.27) and T scores (P=0.04, r=0.26) calculated from QCT. This study aims to evaluate further a previously developed MRI-based BMD grading system against QCT-derived values. A high VBQ score was found to be an excellent predictor of osteoporosis and to be able to distinguish between vertebrae in healthy and osteoporotic states.
