Digital tomosynthesis derived textural and geometric measures of vertebral bone quality in postmenopausal women with primary hyperparathyroidism.

PURPOSE: Risk of vertebral fractures is increased in primary hyperparathyroidism (PHPT). Bone qualities affected by PHPT are not necessarily reflected in bone mineral density (BMD), requiring imaging modalities with capability to capture bone microstructure and geometry. Digital tomosynthesis (DTS) imaging is a method with such capability. Therefore, the objectives of this study were to determine (i) vertebral bone quality differences between women who have established PHPT and normal controls using DTS, and (ii) the extent to which DTS discriminates patients with PHPT from those without.

METHODS: 50 postmenopausal women with established PHPT and 54 control women without PHPT (nPHPT) were DXA imaged to measure spine BMD and trabecular bone score (TBS). They were then DTS imaged to measure vertebral width and area as well as the textural properties of vertebral bone: Degree of anisotropy (DA), fractal dimension (FD), lacunarity (λ), scale-dependent lacunarity (Sλ) and line fraction deviation (LFD).

RESULTS: FD was significantly higher while λ and LFD were significantly lower in the PHPT group than in the nPHPT group. λ was a significant predictor of PHPT status, independently from race, BMD and TBS, raising the overall AUC to 0.805. We observed a dichotomy between the races; larger vertebral area in White patients, but smaller vertebral area in Black patients, was associated with PHPT independently from BMD or TBS.

CONCLUSION: DTS derived vertebral size and textural properties differ between PHPT and nPHPT, discriminate PHPT status independently from DXA, and therefore may be useful in the assessment of bone quality in PHPT.