Comparison of the planimetry and point-counting methods for estimating kidney volume using magnetic resonance imaging

Abstract

Introduction: Kidney volume (KV) is an important parameter for clinical assessment of patients with diabetes or renal artery stenosis and for assessment of kidney transplant candidates. The purpose of this study was to compare KV estimations obtained by using the Cavalieri principle combined with point-counting and planimetry techniques. In addition, we evaluated the results to construct a confidence interval value for KV according to a new approach. Methods: The KV of 15 volunteers (30 kidneys) with no known history of renal diseases. Their age ranged from 18 to 25 years. A 3D-fast spoiled gradient-echo dual echo array spatial sensitivity encoding technique axial plan was performed using 1.5-T scanner. We used magnetic resonance (MR) images using the point-counting and planimetry methods to estimate KV. Results: Kidney volumes obtained by the two different methods were not statistically different and correlated well with each other. The reference values of KV parameters with 95% confidence interval (CI) for lower and upper mean values were 121.50 cm(3) and 144.90 cm(3) respectively. The mean coefficient of error (CE) for KV estimates derived from the stereologic technique was between 0.5 and 1%. Discussion: For accurate and precise estimation of KV, MR imaging with use of the two methods: should be preferred using our MR protocol. We also evaluated a satisfactory predicted CE values and this provided a relatively narrow confidence interval. (C) 2017 Anatomical Society of India. Published by Elsevier, a division of RELX India, Pvt. Ltd. All rights reserved.