FUNCTIONAL-EVALUATION OF NORMAL AND ISCHEMIC KIDNEY BY MEANS OF GADOLINIUM-DOTA ENHANCED TURBOFLASH MR-IMAGING - A PRELIMINARY COMPARISON WITH TC-99M-MAG3 DYNAMIC SCINTIGRAPHY

The functional value of TurboFLASH MR imaging in the assessment of dyn amic contrast enhancement and renal perfusion anomalies was evaluated in seven patients, who also underwent renal scintigraphy in baseline c onditions. The basal renograms obtained from MAG-S scintigraphy (merca pto acetyl triglycine, MAG3-S) and from Gd-DOTA-enhanced turboFLASH MR I were compared. After hydration, the protocol used consisted in breat h-hold coronal turboFLASH acquisitions after IV bolus of Gd-DOTA (4 s every 20 s during 10 min) for MRI, and IV bolus of 370 MBq of Tc-99m-M AG3 followed by 60 frames of 1 s and then 120 frames of 10 s for MAG3- S. Relative renal functions were computed for both methods by calculat ion of the integral of the uptake phase between the first and the seco nd minute. Renograms exhibited 10 normal and 4 ischemic kidneys. There was a close correlation between the contrast enhancement of MRI and i sotopic uptake in normal and ischemic kidneys. Global renograms of MRI correlated with MAG3-S (r =.82,p <.001) with similar curve shape and time to peak. Relative renal function of the right and left kidney wer e closely correlated in ail patients (r =.98, p <.001), although there was a tendency for MR to overestimate MAG3-S evaluation in kidneys wi th severe basal dysfunction. Enhanced turboFLASH provides noninvasive assessment of renal perfusion in patients with renovascular disease. A ccurate renograms are obtained with dynamic-enhanced MRI, but the rela tive renal function seems to be overestimated in low values of ischemi c kidneys, and needs further comparative evaluation.