Kidney Transplant Donor Glomerular Filtration Rate by Iohexol Clearance During Computerized Tomographic Angiography of the Kidneys

Abstract

BackgroundPre-transplantation living-donor kidney function determines remaining donor kidney function and significantly affects post-transplantation allograft function in the recipient. Few transplantation centers perform donor kidney function measurement owing to patient burden. A simplified method of glomerular filtration rate (GFR) measurement after angiographic procedures may facilitate more precise measurement of donor kidney function. MethodsWe evaluated the agreement between a simplified method of GFR measurement after renal computerized tomographic (CT) angiography (index GFR, 100 mL iohexol [350 mg/mL iodine]) and the reference GFR measurement with the use of iodinated radiocontrast media (5 mL bolus of iohexol [300 mg/mL iodine]) among 19 potential living kidney transplant donors. The 24-hour creatinine clearance and GFR estimation equations were additionally examined. Kidney lengths and total and segmented cortical kidney volumes were also measured. ResultsThe index CT angiography GFR performed best with respect to the reference GFR with minimal bias (mean difference, −4 mL/min/1.73 m2), good precision (SD of the difference, 9.8 mL/min/1.73 m2), coefficient of determination (R2) of 0.74, narrow mean coefficient of variation (5% [range 1%–15%]), and high accuracy, with 100% of the values for the index test within 30% of the reference test. The 24-hour urine creatinine clearance values performed poorly. Kidney volumes and length did not significantly correlate with measured GFR. ConclusionsThe CT angiographic GFR measurement could be a useful and more convenient method of donor kidney function evaluation and maintains minimal bias, high precision, and accuracy compared with the reference GFR measurement.