A rapid high-performance semi-automated tool to measure total kidney volume from MRI in autosomal dominant polycystic kidney disease

ObjectivesTo develop a high-performance, rapid semi-automated method (Sheffield TKV Tool) for measuring total kidney volume (TKV) from magnetic resonance images (MRI) in patients with autosomal dominant polycystic kidney disease (ADPKD).MethodsTKV was initially measured in 61 patients with ADPKD using the Sheffield TKV Tool and its performance compared to manual segmentation and other published methods (ellipsoidal, mid-slice, MIROS). It was then validated using an external dataset of MRI scans from 65 patients with ADPKD.ResultsSixty-one patients (mean age 4514years, baseline eGFR 7632ml/min/1.73m(2)) with ADPKD had a wide range of TKV (258-3680ml) measured manually. The Sheffield TKV Tool was highly accurate (mean volume error 0.55.3% for right kidney, -0.75.5% for left kidney), reproducible (intra-operator variability -0.2 +/- 1.3%; inter-operator variability 1.1 +/- 2.9%) and outperformed published methods. It took less than 6min to execute and performed consistently with high accuracy in an external MRI dataset of T2-weighted sequences with TKV acquired using three different scanners and measured using a different segmentation methodology (mean volume error was 3.45 +/- 3.96%, n=65).Conclusions The Sheffield TKV Tool is operator friendly, requiring minimal user interaction to rapidly, accurately and reproducibly measure TKV in this, the largest reported unselected European patient cohort with ADPKD. It is more accurate than estimating equations and its accuracy is maintained at larger kidney volumes than previously reported with other semi-automated methods. It is free to use, can run as an independent executable and will accelerate the application of TKV as a prognostic biomarker for ADPKD into clinical practice.Key Points center dot This new semi-automated method (Sheffield TKV Tool) to measure total kidney volume (TKV) will facilitate the routine clinical assessment of patients with ADPKD.center dot Measuring TKV manually is time consuming and laborious.center dot TKV is a prognostic indicator in ADPKD and the only imaging biomarker approved by the FDA and EMA