Hemodynamic Effects of Furosemide on Renal Perfusion as Evaluated by ASL-MRI

Rationale and Objectives: The aim of this study was to investigate the short-term effects of furosemide on renal perfusion by using arterial spin labeling (ASL) magnetic resonance imaging. Materials and Methods: Eleven healthy human subjects were enrolled in the study. The measurement of renal blood flow (RBF) was performed by applying an ASL technique with flow-sensitive alternating inversion recovery spin preparation and a single-shot fast spin-echo imaging strategy on a 3.0-T magnetic resonance scanner. For all subjects, the ASL magnetic resonance images were obtained before agent injection as a baseline scan. Then 20 mg of furosemide was injected intravenously. Postfurosemide ASL images were acquired following administration to evaluate the renal hemodynamic response. Results: Postinjection scans showed that cortical RBF decreased from 366.59 +/- 41.19 mL/100 g/min at baseline to 314.33 +/- 48.83 mL/100 g/min at 10 minutes after the administration of furosemide (paired t test, P = .04 vs baseline), and medullary RBF decreased from 118.59 +/- 24.69 mL/100 g/min at baseline to 97.38 +/- 18.40 mL/100 g/min at 10 minutes after the administration of furosemide (paired t test, P = .01 vs baseline). There was a negative correlation between the furosemide-induced diuretic effect and the reduction of RBF (Spearman's r = -0.61). Conclusions: The dominant hemodynamic effect of furosemide on the kidney is associated with a decrease in both cortical and medullary blood perfusion. Furthermore, the quantitative ASL technique may provide an alternative way to noninvasively monitor the change in renal function due to furosemide administration.