Diagnostic performances and clinical usefulness of comprehensive non-commercial software for renogram analysis: Values of renal output efficiency and normalized residual activity in suspected kidney outflow obstruction

Introduction/Objective. Nuclear Medicine Section of IAEA has developed the software for dynamic renal scintigraphy, which allows calculation of advanced parameters of drainage: renal output efficiency (OE) and normalized residual activity (NORA). The aim of this study was to validate IAEA software by comparing results of parameters of renal drainage in normal subjects against their established reference values and to assess diagnostic accuracy of OE and NORA in distinguishing between obstruction/unobstruction. Methods. 55 patients with suspected obstruction and 36 kidney donors were investigated. Group A consisted of 24 obstructed kidneys, Group B of 37 kidneys with dilated urinary tract and Group C of 72 normal kidneys. 40min acquisition was applied. Furosemide was administered after 20min. Post-micturition image was acquired at 50min. Parameters analyzed were: OE at 20min (OE20) and at the end of furosemide test (OE40), NORA at 20min (NORA20) and after micturition (NORAPM). One-way ANOVA was used for evaluating differences between Groups. Ability of OE40 and NORAPM to distinguish between obstruction/unobstruction was determined by ROC curve analysis. The sensitivity, specificity, area under the curve and cutoff values were analyzed. Results. Excellent agreement of our results with established OE and NORA values was found. Difference between Groups was significant for OE20, OE40 NORA20 and NORAPM (p < 0.001). Cut-off values for obstruction were 82% and 0.11 for OE40 and NORAPM, respectively. Conclusion. IAEA software gives reliable analysis of diuretic renography and helps to better diagnose obstruction. IAEA should be encouraged to produce final version of the software and to release it through Web site.

Dynamic ultrasound for assessing obstructions in the upper urinary tracts: Usefulness and reliability

Renal ultrasound is not a functional type of examination, which means it cannot be used to determine the degree of obstruction of the upper urinary tract, for which more or less invasive exams such as Whitaker's test, renogram and/or urography must be perfomed. Dynamic ultrasound with furosemide test gives information on the morphology and also the degree of obstruction and is extremely useful in the pre and post-operative assessment of patients with upper urinary tract pathologies. A total of 72 renoureteral units in 39 patients were studied. Patients with a normal “dynamic” ultrasound picture were excluded, while the others were also studied with renogram and/or urography. Data analysis shows dynamics ultrasound reliability is on a par with that of the above-mentioned invasive methods (88–95%). Given the simplicity of use and its availability in all hospital structures, it is therefore considered that dynamic ultrasound should be used immediately in studying obstructions of the upper urinary tracts.

Aldosterone response to adrenocorticotrophin and furosemide in primary aldosteronism after prolonged spironolactone treatment

Yagi A, Ichikawa S, Sakamaki T, Ono, Z, Sato K, Nakamura T, Sakamoto H, Murata K. Aldosterone response to adrenocorticotrophin and furosemide in primary aldosteronism after prolonged spironolactone treatment. Eur J Endocrinol 1994;131:215–20. ISSN 0804–4643 We evaluated the effects of prolonged spironolactone treatment on aldosterone secretion in patients with primary aldosteronism. The patients were hospitalized and underwent a furosemide test with or without dexamethasone, as well as an adrenocorticotrophin (ACTH) test. In untreated patients, neither plasma renin activity (PRA) nor plasma aldosterone showed a response in the furosemide test. In patients receiving spironolactone, furosemide increased significantly both the PRA and the plasma aldosterone concentration (from 2.6±0.8 to 7.0±2.0 μg·1−1 · h−1 (p < 0.05) and from 345.6 ± 55.8 to 492.7 ± 76.8 ng/l (p < 0.05), mean ± sem, respectively). Dexamethasone administration had no effect on the results of the furosemide test (p > 0.1). However, dexamethasone tended to decrease the basal plasma aldosterone concentration in the untreated patients, but not in the patients receiving spironolactone. In the ACTH test, the plasma aldosterone concentration increased significantly in the untreated patients (from 549.0± 69.8 to 1169.3 ± 165.5 ng/l, p <0.01), 0.01), but there was no significant aldosterone response in the spironolactone-treated patients (from 885.5 ± 204.9 to 1260.3 ± 289.2 ng/l, p> 0.1). We conclude that aldosterone secretion is mainly dependent on ACTH in the untreated patients with primary aldosteronism and is more strongly regulated by the renin–angiotensin system during spironolactone treatment. Atsuko Yagi, Second Department of Internal Medicine, Gunma University School of Medicine, 3-39-15, Showa-machi, Maebashi, Gunma 371, Japan