Measuring Total Kidney Volume in Patients with ADPKD

In patients with autosomal dominant polycystic kidney disease (ADPKD), total kidney volume is a key measure of the risk of disease progression. Current methods of measuring total kidney volume are time-consuming and labor intensive, and some facilities are equipped to measure total kidney volume. Ziba Mansoori, MD, and colleagues have developed a technique that provides timely and reliable quantification of total kidney volume using any sequence of abdominal magnetic resonance imaging (MRI).

The technique was described during a poster session at Kidney Week 2019 in a poster titled Simplification of Total Kidney Volume Measurement Procedures for ADPKD.

The researchers selected abdominal MRI scans of 74 consecutive patients from the University of California at San Francisco Polycystic Kidney Disease Center of Excellence. The measurement technique used functionality that was readily available in an FDA-approved commercial medical imaging analysis software, Ziosoft. Various types of scanners (GE, Philips) and field strengths (1.5 T, 3T) were used to in the scans. Coronal T2-weighted DICOM (Digital Imaging and Communications in Medicine) images were used for the measurements: single shot fast spin echo/half-Fournier, slice thickness between 3 and 9 mm.

The outer kidney contour was manually defined by tracing on each slice. The contour from each two-dimensional slice was merged to create a true three-dimensional volume of the kidney. Calibration was achieved using parameters available in DICOM images. In some cases, cystic volume was measured for each kidney via a binary intensity value thresholding. Digital subtraction of cystic volume from total kidney volume was used to determine non-cystic volume.

The average time to implement the measures on standard non-contrast MRI was 30 minutes. A comparison of the total kidney volume to measurements obtained by alternative methodology reported by prior institutions on the same scans revealed a concordance of more than 90%.

“Our technique is readily applicable to routine MRI images obtained for clinical purposes in ADPKD patients. Use of this technique may improve risk stratification availability for ADPKD patients,” the researchers said.

Source: Mansoori Z, Swarnakar V, Park M. Simplification of total kidney volume measurement procedures for ADPKD. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2019 (Abstract TH-PO831), November 7, 2019, Washington, DC.