Renal Diffusion-Weighted Imaging in Healthy Dogs: Reproducibility, Test-Retest Repeatability, and Selection of the Optimal b-value Combination

Sang-Kwon Lee; Juryeoung Lee; Seolyn Jang; Eunji Lee; Chang-Yeop Jeon; Kyung-Seoub Lim; Yeung Bae Jin; Jihye Choi

doi:10.3389/fvets.2021.641971

Renal Diffusion-Weighted Imaging in Healthy Dogs: Reproducibility, Test-Retest Repeatability, and Selection of the Optimal b-value Combination

Front Vet Sci. 2021 Jul 2:8:641971. doi: 10.3389/fvets.2021.641971. eCollection 2021.

Authors

Sang-Kwon Lee¹, Juryeoung Lee¹, Seolyn Jang¹, Eunji Lee¹, Chang-Yeop Jeon², Kyung-Seoub Lim³, Yeung Bae Jin⁴, Jihye Choi¹

Affiliations

¹ College of Veterinary Medicine and BK21 Plus Project Team, Chonnam National University, Gwangju, South Korea.
² National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, South Korea.
³ Futuristic Animal Resource and Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, South Korea.
⁴ College of Veterinary Medicine, Gyeongsang National University, Jinju, South Korea.

Abstract

Diffusion-weighted imaging (DWI) magnetic resonance imaging can evaluate alterations in the microstructure of the kidney. The purpose of this study was to assess the apparent diffusion coefficient (ADC) and the intravoxel incoherent motion model (IVIM) parameters of a normal kidney in healthy dogs, to evaluate the effect of b-value combinations on the ADC value, and the reproducibility and test-retest repeatability in monoexponential and IVIM analysis. In this experimental study, the ADC, pure diffusion coefficient (D), pseudodiffusion coefficient (D^*), and perfusion fraction (f _p) were measured from both kidneys in nine healthy beagles using nine b-values (b = 0, 50, 70, 100, 150, 200, 500, 800, and 1,000 s/mm²) twice with a 1-week interval between measurements. Interobserver and intraobserver reproducibility, and test-retest repeatability of the measurements were calculated. ADC values were measured using 10 different b-value combinations consisting of three b-values each, and were compared to the ADC obtained from nine b-values. All the ADC, D, D^*, and f _p values measured from the renal cortex, medulla, and the entire kidney had excellent interobserver and intraobserver reproducibility, and test-retest repeatability. The ADC obtained from a b-value combination of 0, 100, and 800 s/mm² had the highest intraclass correlation coefficient with the ADC from nine b-values. The results of this study indicated that DWI MRI using multiple b-values is feasible for the measurement of ADC and IVIM parameters with high reproducibility and repeatability in the kidneys of healthy dogs. A combination of b = 0, 100, and 800 s/mm² can be used for ADC measurements when multiple b-values are not available in dogs.

Keywords: b-value; canine; diffusion-weighted magnetic resonance imaging; kidney; renal fibrosis.