Quantification of Renal Perfusion: Comparison of Arterial Spin Labeling and Dynamic Contrast-Enhanced MRI

Purpose: To provide the first comparison of absolute renal perfusion obtained by arterial spin labeling (ASL) and separable compartment modeling of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Moreover, we provide the first application of the dual bolus approach to quantitative DCE-MRI perfusion measurements in the kidney. Materials and Methods: Consecutive ASL and DCE-MRI acquisitions were performed on six rabbits on a 1.5 T MRI system. Gadolinium (Gd)-DTPA was administered in two separate injections to decouple measurement of the arterial input function and tissue uptake curves. For DCE perfusion, pixel-wise and mean cortex region-of-interest tissue curves were fit to a separable compartment model. Results: Absolute renal cortex perfusion estimates obtained by DCE and ASL were in close agreement: 3.28 +/- 0.59 mL/g/min (ASL), 2.98 +/- 0.60 mL/g/min (DCE), and 3.57 +/- 0.96 mL/g/min (pixel-wise DCE). Renal medulla perfusion was 1.53 +/- 0.35 mL/g/min (ASL) but was not adequately described by the separable compartment model. Conclusion: ASL and DCE-MRI provided similar measures of absolute perfusion in the renal cortex, offering both noncontrast and contrast-based alternatives to improve current renal MRI assessment of kidney function.