PTH and osteoporosis: <h4>Purpose</h4>To evaluate the diagnostic performance of a routine CT-derived vertebral bone density index, the standardized percentage change in bone mineral density (cBMD), for detecting osteoporosis in patients with primary hyperparathyroidism (PHPT), and to explore its association with parathyroid hormone (PTH) compared to Quantitative CT (QCT).<h4>Materials and methods</h4>This retrospective study included 175 consecutive patients with biochemically confirmed PHPT.