BONE METABOLIC-ACTIVITY MEASURED WITH POSITRON EMISSION TOMOGRAPHY AND [F-18] FLUORIDE-ION IN RENAL OSTEODYSTROPHY - CORRELATION WITH BONE HISTOMORPHOMETRY

We evaluated the bone metabolic activity in patients with renal osteod ystrophy using positron emission tomography and [F-18]fluoride ion. Ei ght patients had secondary hyperparathyroidism (HPT), and three had lo w-turnover bone disease. Eleven normal subjects were also studied, and three of the eight HPT patients were reevaluated after therapy. A rat e constant (K) describing the net transport of [F-18] fluoride ion int o a bound compartment in bone was calculated using both a three-compar tment model and Patlak graphical analysis. Values of K were compared w ith biochemical data and with histomorphometric indices. The results i ndicate that K is significantly higher (P < 0.01) in HPT patients than in normal subjects and patients with low-turnover bone disease. Value s of K correlated with serum alkaline phosphatase (r = 0.81) and PTH ( r = 0.93) levels and with histomorphometric indices of bone formation rate (r = 0.84, P < 0.01) and eroded perimeter (r = 0.77, P < 0.05). V alues of K decreased by 40 and 30%, respectively, in two patients who underwent parathyroidectomy and medical therapy. Positron emission tom ography studies of bone using [F-18]fluoride ion can differentiate low turnover from high turnover lesions of renal osteodystrophy and provi de quantitative estimates of bone cell activity that correlate with hi stomorphometric data.