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: This study aimed to clinically validate the global skeletal uptake (GSU) of 99mTc-methylene diphosphonate (99mTc-MDP), and to compare it with a marker of bone formation (i.e. serum osteocalcin or OC) and an index of bone resorption (i.e. urinary deoxypyridinoline or U-DPD) in different endocrine disorders affecting the skeleton. We studied 29 female patients with thyrotoxicosis (TT), 27 with primary hyperparathyroidism (PHPT), 16 with acromegaly (AC), 15 with Cushing’s syndrome (CS), and altogether 110 healthy women matched for age, BMI and menstrual status. In all subjects total body digital scan images (TBDS) were acquired at 5 min and at 4 h after the administration of 99mTc-MDP; the whole body retention (WBR) of the tracer was measured by counting two identical sets of rectangular ROIs, and GSU was subsequently calculated by drawing an irregular ROI on 4 h TBDS images. Serum OC was assessed by IRMA and urinary DPD by fluorometric detection after reverse phase high pressure chromatography. In TT patients GSU (40.0 ± 5.1 vs 36.5 ± 4.8%), OC (19.1 ± 11.8 vs 7.1 ± 2.9 mg/l) and U-DPD (62.4 ± 42.7 vs 19.5 ± 5.3 pmol/pmol) were significantly (p<0.01) higher than in controls. PHPT patients showed GSU (47.2 ± 6.6 vs 37.8 ± 5.3%), OC (38.6 ± 40.9 vs 8.2 ± 2.5 mg/l), and U-DPD (55.0 ± 51.3 vs 21.9 ± 6.1 pmol/pmol) values significantly (p<0.001) higher than controls. In CS patients, GSU (39.6 ± 6.4 vs 32.7 ± 3.5%; p<0.01) and U-DPD (22.8 ± 8.4 vs 16.5 ± 2.7 pmol/pmol; p<0.05) were higher, whereas OC (3.6 ± 2.4 vs 5.2 ± 1.9 mg/l; p<0,05) was lower than in controls. In AC patients, GSU (34.9 ± 5.3 vs 35.2 ± 3.4%) did not differ significantly from controls, whereas OC (16.8 ± 8.8 vs 6.9 ± 2.9 mg/l; p<0.001) and U-DPD (30.9 ± 13.6 vs 21.0 ± 5.7 pmol/pmol; p<0.01) were higher. Stepwise multivariate linear regression analysis was performed with disease activity, creatinine clearance, age, and years since menopause as predictor variables and GSU or OC or U-DPD as dependent variables. The significant partial regression coefficients (r) were: in TT, free triiodothyronine (fT3) with GSU (r = 0.37; p<0.005), Ln OC (r = 0.30; p = NS), Ln U-DPD (r = 0.76; p<0.0001), respectively; in PHPT, PTH with GSU (r = 0.74; p<0.001), Ln OC (r = 0.50; p<0.05), Ln U-DPD (r = 0.64; p<0.001); in CS Ln urinary free cortisol with OC (r = -0.68; p<0.001) and U-DPD (r = 0.66; p<0.05). Our data suggest that GSU could represent a valuable clinical tool for evaluating bone turnover rate in PHPT, CS, TT but not in AC. The behavior of GSU and OC and U-DPD is non-uniform in disorders characterized by a marked uncoupling between bone formation and resorption. [ABSTRACT FROM AUTHOR]

Gastric emptying of two different test liquid meals (500 ml isotonic saline and 500 ml skimmed milk, 1.8% fat) has been measured in 10 (saline) and in 19 (milk) normal volunteers by means of real-time ultrasonography (RUS) and scintigraphy, employed simultaneously. In each subject, saline and milk contained 37 MBq of diethylenetriaminopentacetic acid (DPTA) marked with 99mTc. Determinations were made thereafter every 5 min up to 45 min with saline and every 30 min up to a maximum of 220 min with milk. The determination of gastric emptying by RUS was obtained indirectly through the measurement of gastric dimensions, with a single scan performed at the epigastrium, while the subject was kept in a standing position. At each observation, the percent decrease of gastric measurements and the decay in radioactivity over the gastric region were calculated, blind, by two independent examiners. Linear regression and correlation coefficient were subsequently computed for gastric measurements and decay in radioactivity. The results show that the values obtained with RUS do not differ grossly from the ones obtained with scintigraphy. This suggests that the ultrasonographic determination of gastric dimensions with a single section of the stomach may be a valuable method for use in the evaluation of gastric emptying of liquids. [ABSTRACT FROM AUTHOR]