Diuretic Renography in a Sitting Position with F + 10(sp) Method for Diagnostic Management of Primary Megaureter in Adults

<b>Objective</b> Primary megaureter is a disease defined as the dilatation of the ureter caused by a congenital abnormality of the lower ureteral tract. Adult patients with primary megaureters typically present with no symptoms, making conservative management the preferred treatment. However, if an obstruction is present, we recommend ureteral reimplantation. The major diagnostic challenge is to distinguish which patients need surgical intervention. Ultrasound, computed tomography, and magnetic resonance imaging urogram findings of obstruction may be misleading because they are based on morphological aspects, and persistence of contrast in the upper urinary tract is not specific for obstruction. Renal scintigraphy is the key test for choosing surgical or conservative treatment; historically, the criterion for surgical treatment is the decrease of split renal function (SRF) less than 40%. Unfortunately, SRF might be only an indirect finding of obstruction; otherwise, the 20-minute/peak ratio may offer urologists an earlier, direct, and reliable index of urine outflow in monitoring ureteral flow. This study suggests that the F + 10(sitting position) test, which measures diuretic renography (DR) in a sitting position, is a new and useful way to find out how well primary megaureters are working for diagnosing and treating them. It focuses on the 20-minute/peak ratio that can be found when gravity is favorable. <b>Methods</b> Twenty-eight adult patients (15 males, 13 females) affected by primary megaureter were retrospectively enrolled. Twenty-six patients had unilateral megaureter, and 2 patients had bilateral megaureter, for a total of 30 megaureters radiologically confirmed (16 left, 14 right). In total, we performed twenty-eight 99mTc-mercaptoacetyltriglycine DR in a sitting position using the F + 10 (sitting position) method. In our series, 17 patients received conservative treatment, and 11 patients underwent ureteral reimplantation. <b>Results</b> Based on the 20-minute/peak ratio values, 17 out of 30 megaureters were diagnosed as obstructed. A discordance between SRF and 20-minute/peak ratio findings has been seen. No side effects were seen. <b>Conclusion</b> A decrease in SRF is an indirect and late index of obstruction. Twenty-minute/peak ratio measured by DR in sitting position may improve the sensitivity and accuracy of the test for diagnosis of obstructive megaureters.