Multiparametric renal MRI assessments in adults for evaluation of chronic unilateral obstructive uropathy: Arterial spin labeling as the robust functional biomarker

Isotope diuretic renography, the accepted functional reference standard, carries limitations including radiation exposure, limited availability, and poor anatomical resolution.To prospectively evaluate the diagnostic value of functional MRI 3 Tesla comprising apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM), diffusion kurtosis (DK), and arterial spin labeling (ASL) for discriminating chronic unilateral urinary obstruction from healthy kidneys, using isotope glomerular filtration rate (GFR) as the reference standard.

Sixty participants: 30 adults confirmed chronic unilateral upper urinary tract obstruction (mean age 40.1 +/- 12.6years; 19 male) and 30 matched healthy volunteers (mean age 36.4 +/- 11.2 years; 18 male). Cortical ADC, medullary ADC, IVIM true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f), diffusion kurtosis, and ASL renal blood flow were measured independently by two radiologists and correlated with isotope-derived GFR.