Quantitative residual cortical activity measurement: appropriate test for diagnosis of renal artery stenosis?

OBJECTIVES: To evaluate the diagnostic validity of quantitative measurement of residual cortical activity (RCA) in renal artery stenosis (RAS). METHODS: In 45 patients with a high clinical likelihood of renovascular hypertension (RVH) and unimpaired renal function, dynamic imaging was performed after an intravenous bolus injection of 148 MBq (99m)Tc MAG3 for both baseline renoscintigraphy and captopril renography following oral application of 50 mg captopril. RCA was measured according to the Sfakianakis method: RCA = cortical counts at 20 min/counts at peak x100%. An increase in RCA of >/=5% from baseline was considered indicative of RAS. After renography, all patients underwent selective transfemoral angiography with the digital subtraction technique. A luminal reduction of >/=50% was considered as proof of RAS. RESULTS: The number of kidneys that had a change of >/=5% in RCA values was 12 (27.2%) in normal kidneys, 7 (58.3%) in the patients with bilateral RAS, 14 (82.3%) in the patients with unilateral RAS, and 21 (72.4%) in overall kidneys with RAS. The positive test ratio in pathologic groups was significantly higher than normal (p < 0.05). The sensitivity and specificity of the RCA test were 72.4 and 72.7%, respectively; the positive and negative predictive values were 63.6 and 80%, respectively. CONCLUSION: Quantitative measurements of RCA can be used as a diagnostic parameter of renal artery stenosis and may contribute of the diagnostic accuracy of visual interpretation and other renographic diagnostic criteria.

Intense muscle uptake of gallium-67 in a patient with sarcoidosis.

Sarcoidosis has been associated with muscle involvement. In general, this involvement remains asymptomatic. The following case report demonstrates a patient with a 4-mo history of sarcoidosis who reported severe fatigue and slight muscular complaints at a regular checkup. Gallium scintigraphy indicated unexpected and unusually extensive muscular localizations of the disease. The latter findings were confirmed by examination of biopsy specimens. The importance of gallium scintigraphy lies in the possibility of wholebody screening for inflammation localizations, particularly when physical, laboratory, lung function and radiographic examinations fail to provide convincing evidence of active sarcoidosis. Furthermore, it can be helpful in the follow-up of the effect of supportive treatment.