Assessment of renal function using intravoxel incoherent motion diffusion‐weighted imaging and dynamic contrast‐enhanced MRI. Issue 2 (8th February 2016) - Bane, Octavia
Abstract : Purpose: To assess the correlation between each of intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) and dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) metrics in renal parenchyma with renal function, in a cohort of patients with chronic liver disease. Materials and Methods: Thirty patients with liver disease underwent abdominal MRI at 1.5T, including a coronal respiratory‐triggered IVIM‐DWI sequence and a coronal 3D FLASH DCE‐MRI acquisition. Diffusion signals in the renal cortex and medulla were fitted to the IVIM model to estimate the diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (PF). The apparent diffusion coefficient (ADC) was calculated using all b‐values. The glomerular filtration rate (GFR), cortical and medullary renal plasma flow (RPF), mean transit times (MTT) of vascular and tubular compartments and the whole kidney, were calculated from DCE‐MRI data by fitting to a three‐compartment model. The estimated GFR (eGFR) was calculated from serum creatinine measured 30 ± 27 days of MRI. Results: ADC, PF, and RPF were significantly higher in renal cortex vs. medulla ( P < 10 −5 ). DCE‐MRI GFR significantly correlated with, but underestimated, eGFR (Spearman's r/P = 0.49/0.01). IVIM‐DWI parameters were not significantly correlated with eGFR. DCE‐MRI GFR correlated weakly with D (cortex, r/P = 0.3/0.03; medulla r/P = 0.27/0.05) and ADC (cortex r/P = 0.28/0.04; medulla r/P = 0.34/0.01). Weak correlations were observed for pooled cortical and medullar RPF with PF ( r/P = 0.32/10 −3 ) and with ADC ( r/P = 0.29/0.0025). Significant negative correlations were observed for vascular MTT with cortical D* ( r/P = −0.38/0.004) and D*×PF ( r/P = −0.34/0.01). Conclusion: The weak correlations between renal IVIM and DCE‐MRI perfusion parameters imply that these functional measures could be complementary. J. Magn. Reson. Imaging 2016;44:317–326.