Assessment of therapeutic effect in patients with secondary hyperparathyroidism using bone scintigraphy

The semi-quantitative method of bone scintigraphy [bone to soft tissue (B/ST) ratio] has been used in diagnosing and evaluating systemic metabolic bone diseases. The aim of this study is to evaluate of the therapeutic effect of secondary hyperparathyroidism (SHP).

The subjects were ten hemodialysis patients with SHP. Seven patients underwent parathyroidectomy (PTX), and 22-Oxacalcitoriol (derivative of 1,25-dihydroxyvitamin D3) (OCT) was given to three patients. Bone scintigraphy and blood tests [intact parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (Ca), phosphorus (P), bone alkaline phosphatase (BALP), and deoxypridinoline (DPYD)] were performed before and after treatment. Regions of interest were drown around cranium, lumbar vertebrae, femoral neck and soft tissue of left medial thigh to calculate the B/ST ratio.

The B/ST ratios of cranium, lumbar vertebrae, and femoral neck were reduced significantly after PTX (cranium, p = 0.0079, lumbar vertebrae, p = 0.0282, femoral neck, p = 0.0252). Intact PTH, ALP, Ca, P, BALP and DPYD levels were reduced significantly after PTX (intact PTH, p = 0.003, Ca, p = 0.0005, P, p = 0.0393, ALP, p = 0.0051, DPYD, p = 0.0232, BALP, p = 0.0324). After OCT administration, the B/ST ratio of each bony region showed tendency to diminish, although not significantly. Intact PTH levels were reduced significantly, although ALP, BALP, and DPYD levels were not. Ca and P levels were increased significantly because of the medicinal action of OCT.

The B/ST ratio of cranium may be non-invasive method and have potential in evaluating the therapeutic effect of SHP.