Intra-Scanner and Inter-Scanner Reproducibility of Automatic White Matter Hyperintensities Quantification.

Chunjie Guo,Kai Niu,Lin Shi,Meng Zhao,Zhuo Wang,Defeng Wang,Li Sun,Huimao Zhang,Yishan Luo,Wan’An Zhu

doi:10.3389/fnins.2019.00679

Abstract

Objectives: To evaluate white matter hyperintensities (WMH) quantification reproducibility from multiple aspects of view and examine the effects of scan–rescan procedure, types of scanner, imaging protocols, scanner software upgrade, and automatic segmentation tools on WMH quantification results using magnetic resonance imaging (MRI).Methods: Six post-stroke subjects (4 males; mean age = 62.8, range = 58–72 years) were scanned and rescanned with both 3D T1-weighted, 2D and 3D T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MRI across four different MRI scanners within 12 h. Two automated WMH segmentation and quantification tools were used to measure WMH volume based on each MR scan. Robustness was assessed using the coefficient of variation (CV), Dice similarity coefficient (DSC), and intra-class correlation (ICC).Results: Experimental results show that the best reproducibility was achieved by using 3D T2-FLAIR MRI under intra-scanner setting with CV ranging from 2.69 to 2.97%, while the largest variability resulted from comparing WMH volumes measured based on 2D T2-FLAIR MRI with those of 3D T2-FLAIR MRI, with CV values in the range of 15.62%–29.33%. The WMH quantification variability based on 2D MRIs is larger than 3D MRIs due to their large slice thickness. The DSC of WMH segmentation labels between intra-scanner MRIs ranges from 0.63 to 0.77, while that for inter-scanner MRIs is in the range of 0.63–0.65. In addition to image acquisition, the choice of automatic WMH segmentation tool also has a large impact on WMH quantification.Conclusion: WMH reproducibility is one of the primary issues to be considered in multicenter and longitudinal studies. The study provides solid guidance in assisting multicenter and longitudinal study design to achieve meaningful results with enough power.

Highlights

While there are so many methods studying the accuracy of white matter hyperintensities (WMH) segmentation and quantification, few studies examined the reproducibility of WMH quantification
It can be observed that the T2-fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) have a large variability in appearance across scanners, which brings great challenge in obtaining consistent WMH volumetric measurement
Even if the same scanner and imaging parameters are used within a short time period, the T2-FLAIR MRIs look different in tissue and WMH contrast

Summary

Introduction

Commonly found on T2-weighted T2-FLAIR brain MR images in the elderly, are associated with a number of neuropsychiatric disorders, including multiple sclerosis (MS) (Filippi et al, 2016),vascular dementia, Alzheimer’s disease (AD) (Fazekas et al, 1996; Hirono et al, 2000), mild cognitive impairment (DeCarli et al, 2001), stroke (Fazekas et al, 1993), and Parkinson’s disease (Marshall et al, 2006), and even in patients with primary mental disorders including mood disorders and schizophrenia spectrum disorders (Brown et al, 1995). WMH usually have a higher signal intensity compared to the normal-appearing white matter on FLAIR sequences and may appear iso- or hypointense on T1-weighted MR images. It can be measured quantitatively and non-invasively on large population samples and have been proposed as an intermediate marker, which could be used for the identification of new risk factors and potentially as a surrogate end point in clinical trials (Schmidt et al, 2004). While there are so many methods studying the accuracy of WMH segmentation and quantification, few studies examined the reproducibility of WMH quantification

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