Three-Dimensional Reconstruction Volume: A Novel Method for Volume Measurement in Kidney Cancer

Abstract

BACKGROUND AND PURPOSE: The role of volumetric estimation is becoming increasingly important in the staging, management, and prognostication of benign and cancerous conditions of the kidney. We evaluated the use of three-dimensional reconstruction volume (3DV) in determining renal parenchymal volumes (RPV) and renal tumor volumes (RTV). We compared 3DV with the currently available methods of volume assessment and determined its interuser reliability. PATIENTS AND METHODS: RPV and RTV were assessed in 28 patients who underwent robot-assisted laparoscopic partial nephrectomy for kidney cancer. Patients with a preoperative creatinine level of <1.2 mg/dL with available scans were selected. RPV and RTV were then assessed using 3DV, as well as cylindrical approximation for RPV and spherical approximation for RTV as described previously in the literature. Measures of the same quantity from each method were then compared. In addition, interuser reliability was determined for 3DV. RESULTS: Calculated volumes differed widely in comparison with 3DV. For example, cylindrical volumes for the contralateral kidney pre- and postsurgery overestimated 3D reconstruction volumes by 15% to 102% and 12% to 101%, respectively. In addition, volumes obtained from 3DV displayed high interuser reliability regardless of experience. CONCLUSIONS: 3DV provides a highly reliable way of assessing kidney volumes. Given that 3DV takes into account visible anatomy, the differences observed using previously published methods can be attributed to the failure of geometry to accurately approximate kidney or tumor shape. 3DV provides a more accurate, reproducible, and clinically useful tool for urologists looking to improve patient care using analysis related to volume.