To validate a new procedure for the three-dimensional estimation of total renal parenchyma volumeusing a structured-light infrared laser sensor.

To evaluate the accuracy of the sensor for assessing renal volume, we performed 3 experiments. Twenty freshly excised porcine kidneys were obtained. Experiment A, the water displacement method was used to obtain a determination of the renal parenchyma volume after immersing every kidney into 0.9% saline. Thereafter a structured sensor (Occipital, San Francisco, CA) was used to scan the kidney. Kidney sample surface was presented initially as a mesh and then imported into MeshLab (Visual Computing Lab, Pisa, Italy) software to obtain the surface volume. Experiment B, a partial excision of the kidney with measurement of the excised volume and remnant was performed. Experiment C, a renorrhaphy of the remnant kidney was performed then measured. Bias and limits of agreement (LOA) were determined using the Bland-Altman method. Reliability was assessed using the intraclass correlation coefficient (ICC).

Experiment A, the sensor bias was −1.95mL (LOA: −19.5 to 15.59, R² = 0.410) with slightly overestimating the volumes. Experiment B, remnant kidney after partial excision and excised kidneyvolume were measured showing a sensor bias of −0.5mL (LOA −5.34 to 4.20, R²= 0.490) and −0.6mL (LOA: −1.97.08 to 0.77, R² = 0.561), respectively. Experiment C, the sensor bias was −0.89mL (LOA −12.9 to 11.1, R²= 0.888). ICC was 0.9998.

The sensor is a reliable method for assessing total renal volume with high levels of accuracy.