Scan\u2013rescan and inter-vendor reproducibility of neurite orientation dispersion and density imaging metrics

Christina Andica,Shigeki Aoki,Toshiaki Akashi,Wataru Uchida,Masaaki Hori,Masahiro Abe,Koji Kamagata,Hiroshi Kusahara,Takuya Hayashi,Yuya Saito,Shohei Fujita,Kouhei Kamiya,Akihiko Wada,Akifumi Hagiwara

doi:10.1007/s00234-019-02350-6

Abstract

PurposeThe reproducibility of neurite orientation dispersion and density imaging (NODDI) metrics in the human brain has not been explored across different magnetic resonance (MR) scanners from different vendors. This study aimed to evaluate the scan–rescan and inter-vendor reproducibility of NODDI metrics in white and gray matter of healthy subjects using two 3-T MR scanners from two vendors.MethodsTen healthy subjects (7 males; mean age 30 ± 7 years, range 23–37 years) were included in the study. Whole-brain diffusion-weighted imaging was performed with b-values of 1000 and 2000 s/mm2 using two 3-T MR scanners from two different vendors. Automatic extraction of the region of interest was performed to obtain NODDI metrics for whole and localized areas of white and gray matter. The coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the scan–rescan and inter-vendor reproducibilities of NODDI metrics.ResultsThe scan–rescan and inter-vendor reproducibility of NODDI metrics (intracellular volume fraction and orientation dispersion index) were comparable with those of diffusion tensor imaging (DTI) metrics. However, the inter-vendor reproducibilities of NODDI (CoV = 2.3–14%) were lower than the scan–rescan reproducibility (CoV: scanner A = 0.8–3.8%; scanner B = 0.8–2.6%). Compared with the finding of DTI metrics, the reproducibility of NODDI metrics was lower in white matter and higher in gray matter.ConclusionThe lower inter-vendor reproducibility of NODDI in some brain regions indicates that data acquired from different MRI scanners should be carefully interpreted.

Highlights

Diffusion-weighted imaging (DWI) is a form of magnetic resonance (MR) imaging widely used to non-invasively evaluate the brain by measuring the displacement of water molecules in biological tissues in vivo [1, 2]
This study explored the scan–rescan and inter-vendor reproducibility of neurite orientation dispersion and density imaging (NODDI) metrics (ICVF, orientation dispersion index (ODI), and isotropic volume fraction (ISO)) obtained using two MR scanners from different vendors in a singleinstitution setting
In contrast to a study by Chung et al [6], who demonstrated higher scan–rescan coefficient of variation (CoV) for NODDI metrics than for diffusion tensor imaging (DTI) metrics in the human brain, our study showed that the scan– rescan reproducibility of NODDI metrics using both scanners is comparable with that of DTI metrics

Summary

Introduction

Diffusion-weighted imaging (DWI) is a form of magnetic resonance (MR) imaging widely used to non-invasively evaluate the brain by measuring the displacement of water molecules in biological tissues in vivo [1, 2]. Among the available DWI techniques, diffusion tensor imaging (DTI) [3] is most commonly used to observe brain microstructural changes in neurological abnormalities [4, 5]. DTI is insufficient for modeling non-Gaussian diffusion scatter patterns in biological structures [6, 7]. DTI is not the preferred method for evaluation of gray matter (GM) ( the cortex) because it cannot thoroughly describe microstructural abnormalities in GM due to isotropic water diffusion [8]

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