Age Dependence of T1 Perfusion MRI-Based Hemodynamic Parameters in Human Kidneys

Purpose:
To determine the association between renal cortical perfusion parameters from T1-DCE magnetic resonance imaging (MRI) and age in human kidney.
Materials and Methods:
Thirty-five patients (mean age: 53 years, SD 15 years) were imaged using inversion recovery (IR)-prepared FLASH (pulse repitition time [TR] 4.4 msec, echo time [TE] 2.2 msec, inversion time [TI] 180 msec, FA 50°, matrix 128 x 256, 0.3 sec/slice) during the injection of Gadolinium-DTPA. Tissue concentration-time courses were deconvolved. Renal blood flow (RBF), volume of distribution (RVD), and mean transit time (MTT) were derived from the resulting impulse response function.
Results:
Mean RBF, RVD, and MTT were 127 mL/min/100 mL (SD 81 mL/min/100 mL), 40 mL/100 mL (SD 23 mL/100 mL), and 22 sec (SD 9 sec). A significant moderately negative correlation was found between RBF and age (R2=0.447, P = 0.007), RVD and age (R 2=0.420, P = 0.012). MTT and age did not show a significant correlation (R 2= 0.017, P = 0.924). Repeating this analysis for each gender revealed a moderate age dependence of RBF (R 2 = 0.600 with P = 0.009) and RVD (R 2 = 0.540 with P = 0.021) in the male group only.
Conclusion:
T1-DCE quantitative perfusion MRI was sufficiently sensitive to demonstrate a significant negative correlation of RBF and RVD with patient age. This was due to a moderate age dependence of these quantities in males that seems to be absent in females.