Magnetic resonance urography: initial experience of a low-dose Gd-DTPA-enhanced technique

Contrast-enhanced magnetic resonance urography (MRU) is a promising tool in the evaluation of the renal collecting system, but it can be limited by T2 * effects resulting from hyperconcentrated gadolinium chelates. The aim of this study was to evaluate a low-dose dimeglumine gadopentetate (Gd-DTPA) M RU technique consisting of a dynamic,fast low-angle-shot (FLASH) 2D sequenc e and a static fast imaging in steady state precession (FISP) 3D sequence f or depicting the kidneys and urinary tract. The Gd-DTPA dose (0.01 mmol/kg) was established experimentally in a healthy volunteer study. Ninety-one pa tients presenting with various renal disorders were examined with a low-dos e Gd-DTPA MRU and a T2-weighted turbo spin echo (TSE) MRU technique on a 1. 5-T system. Image quality and diagnostic value were considered at least sat isfactory in 98.9% of the FLASH 2D studies, 83.5% of the FISP 3D studies an d 78.5% of the TSE T2-weighted studies. Typical enhancement patterns were e stablished for the renal cell carcinoma and transitional cell carcinoma. Th e major limitations were motion artefacts and insufficient hydration of the patients. Low-dose Gd-DTPA MRU appears to be a useful technique in the eva luation of the kidneys and urinary tract, especially in cases of renal tumo urs.