Opportunistic computed tomography to identify osteoporosis in primary hyperparathyroidism using sestamibi SPECT/CT scans

Osteoporosis is a well-recognized complication of primary hyperparathyroidism (PHPT).

We aimed to develop an osteoporosis prediction model for PHPT patients using opportunistic computed tomography (CT)-derived Hounsfield unit (HU) measurements from sestamibi SPECT/CT.

Sestamibi SPECT/CT images from 81 PHPT patients (60 with and 21 without osteoporosis diagnosed by dual-energy x-ray absorptiometry) were analyzed retrospectively. HUs of vertebral bodies were measured. Receiver operating characteristic (ROC) analysis was performed to determine the optimal HU cutoff for each vertebra in predicting osteoporosis. Multivariable logistic regression was used to identify independent clinical parameters associated with osteoporosis. A prediction model based on clinical parameters alone was built. Another prediction model was constructed by further incorporating the HU of the vertebra. Model performance improvement was assessed.

Age and body mass index (BMI) were independent risk factors for osteoporosis. The clinical prediction model (age and BMI) achieved an area under the receiver operating characteristic curve (AUROC) of 0.874. Incorporation of HU of T4 vertebra into the clinical model showed the best performance with AUROC of 0.966, sensitivity of 98.2%, and specificity of 85.7%, representing a significant improvement in prediction with change in C-statistics of 0.092 (95% CI, 0.021-0.163; P = .011), net reclassification index of 0.346 (0.041-0.650; P = .026), and incremental discrimination index of 0.329 (0.116-0.542; P = .003). After bootstrap internal validation, the optimism-corrected AUROC was 0.949 (0.882-1.000).

Our study demonstrated the feasibility of integrating vertebral HU measurements from sestamibi SPECT/CT into a clinical prediction model for accurately identifying osteoporosis in PHPT patients, offering a potential tool for efficient bone health management and prioritizing timely surgical interventions.