Variability of non-Gaussian diffusion MRI and intravoxel incoherent motion (IVIM) measurements in the breast

Mami Iima,Rena Sakaguchi,Makiko Kawai,Masako Kataoka,Natsuko Onishi,Akane Ohashi,Sho Koyasu,Kaori Togashi,Katsutoshi Murata,Shotaro Kanao,Vince Grolmusz

doi:10.1371/journal.pone.0193444

Abstract

We prospectively examined the variability of non-Gaussian diffusion magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) measurements with different numbers of b-values and excitations in normal breast tissue and breast lesions. Thirteen volunteers and fourteen patients with breast lesions (seven malignant, eight benign; one patient had bilateral lesions) were recruited in this prospective study (approved by the Internal Review Board). Diffusion-weighted MRI was performed with 16 b-values (0–2500 s/mm2 with one number of excitations [NEX]) and five b-values (0–2500 s/mm2, 3 NEX), using a 3T breast MRI. Intravoxel incoherent motion (flowing blood volume fraction [fIVIM] and pseudodiffusion coefficient [D*]) and non-Gaussian diffusion (theoretical apparent diffusion coefficient [ADC] at b value of 0 sec/mm2 [ADC0] and kurtosis [K]) parameters were estimated from IVIM and Kurtosis models using 16 b-values, and synthetic apparent diffusion coefficient (sADC) values were obtained from two key b-values. The variabilities between and within subjects and between different diffusion acquisition methods were estimated. There were no statistical differences in ADC0, K, or sADC values between the different b-values or NEX. A good agreement of diffusion parameters was observed between 16 b-values (one NEX), five b-values (one NEX), and five b-values (three NEX) in normal breast tissue or breast lesions. Insufficient agreement was observed for IVIM parameters. There were no statistical differences in the non-Gaussian diffusion MRI estimated values obtained from a different number of b-values or excitations in normal breast tissue or breast lesions. These data suggest that a limited MRI protocol using a few b-values might be relevant in a clinical setting for the estimation of non-Gaussian diffusion MRI parameters in normal breast tissue and breast lesions.

Highlights

Diffusion magnetic resonance imaging (MRI) has been shown to be an important diagnostic biomarker for tumor characterization [1], including assessment of breast tumors [2] or treatment responses [3], without the requirement for contrast agents
An example of non-Gaussian diffusion-weighted imaging (DWI) and Intravoxel incoherent motion (IVIM) parametric maps in malignant and benign breast tumors from five b-value datasets with one number of excitations (NEX) is shown in Figs 1 and 2
We examined the changes in behavior of diffusion and perfusion parameters from different diffusion MR acquisition schemes in normal breast tissue, and in malignant and benign breast tumors

Summary

Introduction

Diffusion magnetic resonance imaging (MRI) has been shown to be an important diagnostic biomarker for tumor characterization [1], including assessment of breast tumors [2] or treatment responses [3], without the requirement for contrast agents. Intravoxel incoherent motion (IVIM), which can estimate perfusion at the microcapillary level [7], combined with non-Gaussian diffusion MRI models such as Kurtosis, may provide additional information on water diffusion in breast tissue compared with ADC. Synthetic ADC (sADC), which is obtained only from two key b-values [9], can encompass both nonGaussian and Gaussian diffusion effects compared with the standard ADC diffusion model, without additional scanning time. A range of combinations of high b-values (600–3000 s/mm2) have been reported, and together with the non-Gaussian diffusion effect in tissues, this results in variability in calculated ADC values [10]. It is difficult to compare findings between various reports and multicenter studies, especially for estimation of non-Gaussian diffusion parameters [4, 12, 13]

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