Comparing the interobserver reproducibility of different regions of interest on multi-parametric renal magnetic resonance imaging in healthy volunteers, patients with heart failure and renal transplant recipients

Abstract

Objective To assess interobserver reproducibility of different regions of interest (ROIs) on multi-parametric renal MRI using commercially available software. Materials and methods Healthy volunteers (HV), patients with heart failure (HF) and renal transplant recipients (Tx) were recruited. Localiser scans, T1 mapping and pseudo-continuous arterial spin labelling (pCASL) were performed. HV and Tx also underwent diffusion-weighted imaging to allow calculation of apparent diffusion coefficient (ADC). For T1, pCASL and ADC, ROIs were drawn for whole kidney (WK), cortex (Cx), user-defined representative cortex (rep-Cx) and medulla. Intraclass correlation coefficient (ICC) and coefficient of variation (CoV) were assessed. Results Forty participants were included (10 HV, 10 HF and 20 Tx). The ICC for renal volume was 0.97 and CoV 6.5%. For T1 and ADC, WK, Cx, and rep-Cx were highly reproducible with ICC ≥ 0.76 and CoV < 5%. However, cortical pCASL results were more variable (ICC > 0.86, but CoV up to 14.2%). While reproducible, WK values were derived from a wide spread of data (ROI standard deviation 17% to 55% of the mean value for ADC and pCASL, respectively). Renal volume differed between groups (p < 0.001), while mean cortical T1 values were greater in Tx compared to HV (p = 0.009) and HF (p = 0.02). Medullary T1 values were also higher in Tx than HV (p = 0.03), while medullary pCASL values were significantly lower in Tx compared to HV and HF (p = 0.03 for both). Discussion Kidney volume calculated by manually contouring a localiser scan was highly reproducible between observers and detected significant differences across patient groups. For T1, pCASL and ADC, Cx and rep-Cx ROIs are generally reproducible with advantages over WK values.

Bias and Precision in Magnetic Resonance Imaging‐Based Estimates of Renal Blood Flow: Assessment by Triangulation

“…Absolute RBF values in this study are comparable to those reported by Khatir et al 30 in healthy subjects and Jin et al using breath hold PC, 31 Gillis et al 28 and Shirvani et al 32 using ASL with FAIR labeling and Rankin et al 33 using the same pCASL labeling used in our study. Nevertheless, it is surprising that mean RBF of our healthy participants was substantially lower than reference values in the literature.…”

“…Twenty-five patients (16 males and 9 females, mean age (interquartile range) of 65 (56-72) years) were analyzed and included for comparison. Five healthy volunteers (one male and four females, mean age [interquartile range] of 39 [31][32][33][34][35][36][37][38][39][40] years) completed the four visits at an average of 4 months apart (range between 2 and 7 months).…”

Multiparametric renal magnetic resonance imaging: A reproducibility study in renal allografts with stable function

“…Cortical RBF values obtained in this study are in line with values described in the literature, although only a few articles have previously reported RBF in renal allografts measured with PCASL. Yu et al 25 reported an RBF of 144.73 (49.33) ml/min/100 g in a group of stable patients with a mean eGFR of 72 ml/min/1.73m 2 , using a PCASL 3D-FSE spiral; Wang et al 26 measured an RBF of 204.7 (44.9) ml/min/100 g in stable patients whose eGFR was 77.1 (15.1) ml/min/1.73m 2 , using a similar PCASL sequence; Rankin et al 27 showed an RBF of 239 (84) ml/min/100 g measured with PCASL 3D-TGSE in a group of transplant patients with a mean eGFR of 48 ml/min/1.73m 2 and Ahn et al 28 obtained an RBF of 358 (36) ml/min/100 g with a PCASL BSSFP sequence employing several postlabeling delays, in a study performed shortly after transplantation.…”

Spectral diffusion analysis of kidney intravoxel incoherent motion MRI in healthy volunteers and patients with renal pathologies

“…Furthermore, the midslice of the kidney was assumed to be representative enough of the whole kidney in several previous DWI studies. [36][37][38] The datasets were smoothed with an isotropic 3 × 3 Gaussian kernel to increase SNR. Cortical and medullary ROIs and the tumor and cyst volumes were then manually segmented on the b 0 images by an experienced radiologist (a.l., 11 years of experience) in the open-source image segmentation toolbox ITK-SNAP (Version 3.8.0).…”

“…Only a single image slice containing the center of the right kidney was selected for further analysis because (1) it was not affected by respiratory motion compared with the remaining slices; (2) it contained the maximum parenchymal area, which allowed the largest cortical and medullary regions of interest (ROIs) to be obtained; and (3) both cortex and medulla were clearly visible thus enabling a reliable segmentation. Furthermore, the midslice of the kidney was assumed to be representative enough of the whole kidney in several previous DWI studies 36‐38 . The datasets were smoothed with an isotropic 3 × 3 Gaussian kernel to increase SNR.…”