AUTHOR=Jreige Mario , Hall Nicolas , Becce Fabio , Aubry-Rozier Bérengère , Gonzalez Rodriguez Elena , Schaefer Niklaus , Prior John O. , Nicod Lalonde Marie 

TITLE=A novel approach for fibrous dysplasia assessment using combined planar and quantitative SPECT/CT analysis of Tc-99m-diphosphonate bone scan in correlation with biological bone turnover markers of disease activity

JOURNAL=Frontiers in Medicine

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.1050854

DOI=10.3389/fmed.2022.1050854

ISSN=2296-858X

ABSTRACT=<sec><title>Purpose</title><p>To investigate the emerging role of Tc-99m-labeled diphosphonate (Tc-99m-DPD) uptake quantification by SPECT/CT in fibrous dysplasia (FD) bone lesions and its correlation with biological bone turnover markers (BTMs) of disease activity.</p></sec><sec><title>Materials and methods</title><p>Seven patients (49 ± 16 years) with a confirmed diagnosis of FD were included in this retrospective study. Bone scans with Tc-99m-DPD and quantitative SPECT/CT (xSPECT/CT) were performed. SUV<sub>max</sub> (maximum standard unit value) and SUV<sub>mean</sub> (mean standard unit value) were measured in all FD bone lesions. The skeletal burden score (SBS) was assessed on planar scintigraphy and multiplied by mean SUV<sub><italic>max</italic></sub> and SUV<sub>mean</sub> to generate two new parameters, SBS_SUV<sub>max</sub> and SBS_SUV<sub>mean</sub>, respectively. Planar and xSPECT/CT quantitative measures were correlated with biological BTMs of disease activity, including fibroblast growth factor 23 (FGF-23), alkaline phosphatase (ALP), procollagen 1 intact N-terminal propeptide (P1NP) and C-terminal telopeptide (CTX), as well as scoliosis angle measured on radiographs. Statistical significance was evaluated with Spearman’s correlations.</p></sec><sec><title>Results</title><p>A total of 76 FD bone lesions were analyzed, showing an average SUV<sub>max</sub> and SUV<sub>mean</sub> (g/mL) of 13 ± 7.3 and 8 ± 4.5, respectively. SBS, SBS_SUV<sub>max</sub> and SBS_SUV<sub>mean</sub> values were 30.8 ± 25.6, 358 ± 267 and 220.1 ± 164.5, respectively. Mean measured values of FGF-23 (pg/mL), ALP (U/L), P1NP (μg/L) and CTX (pg/mL) were 98.4 (22–175), 283.5 (46–735), 283.1 (31–1,161) and 494 (360–609), respectively. Mean scoliosis angle was 15.7 (7–22) degrees. We found a very strong positive correlation between planar-derived SBS and CTX (<italic>r</italic> = 0.96, <italic>p</italic> = 0.010), but no significant correlation between SUV<sub>max</sub> or SUV<sub>mean</sub> and biological BTMs. SBS_SUV<sub>max</sub> showed a strong to very strong positive correlation with CTX (ρ = 0.99, <italic>p</italic> = 0.002), FGF-23 (ρ = 0.91, <italic>p</italic> = 0.010), ALP (ρ = 0.82, <italic>p</italic> = 0.020), and P1NP (ρ = 0.78, <italic>p</italic> = 0.039), respectively.</p></sec><sec><title>Conclusion</title><p>This study showed that biological BTMs are significantly correlated with diphosphonate uptake on bone scan, quantified by a new parameter combining information from both planar and quantitative SPECT/CT. Further analysis of bone scan quantitative SPECT/CT data in a larger patient population might help better characterize the skeletal disease burden in FD, and guide treatment and follow-up.</p></sec>