ADC cut points for chronic kidney disease in pathologically-proven cholangiocarcinoma

Apparent diffusion coefficient (ADC) has been shown to indicate renal function in various conditions. As cholangiocarcinoma may have renal involvement due to immune complex-mediated glomerulonephritis, this study aimed to determine whether or not there is any association between ADC values and renal function in these patients.

This was a retrospective, analytical study. The inclusion criteria were age over 18 years, pathologically proven cholangiocarcinoma diagnosis and having undergone either 1.5 T or 3.0 T diffusion-weighted MRI. Chronic kidney disease (CKD) was defined as eGFR less than 60 mL/min/1.73m². Patients' ADC levels in the CKD and non-CKD groups were compared, and subgroup analysis was performed by MRI field strength and type of cholangiocarcinoma.

One hundred fifty-eight patients participated in the study. Most were male (66.46 %), and the average age (SD) was 61.59 years (7.91). Average ADC levels in the CDK and non-CDK group differed significantly, regardless of MRI field strength or type of cholangiocarcinoma (2.11 mm/s² in the ADC group vs 1.91 mm/s² in the non-ADC group; P < 0.001). An ADC cut-point of 1.75 mm/s² yielded sensitivities ranging from 66.67-90.00 in almost all study populations. The distal cholangiocarcinoma group had a perfect cut-point at 1.78 mm/s² with 100 % sensitivity and area under the ROC curve.

Radiologists can use ADC to detect CKD in cholangiocarcinoma patients regardless of MRI field strength or type of cholangiocarcinoma.