Diffusion-Weighted Echo Planar Imaging using MUltiplexed Sensitivity Encoding and Reverse Polarity Gradient in Head and Neck Cancer: An Initial Study.

Amaresha Shridhar Konar,Amita Shukla-Dave,Maggie Fung,Jung Hun Oh,Ramesh Paudyal,Yousef Mazaheri,Vaios Hatzoglou

doi:10.18383/j.tom.2020.00014

Abstract

We aimed to compare the geometric distortion (GD) correction performance and apparent diffusion coefficient (ADC) measurements of single-shot diffusion-weighted echo-planar imaging (SS-DWEPI), multiplexed sensitivity encoding (MUSE)-DWEPI, and MUSE-DWEPI with reverse-polarity gradient (RPG) in phantoms and patients. We performed phantom studies at 3T magnetic resonance imaging (MRI) using the American College of Radiology phantom and Quantitative Imaging Biomarker Alliance DW-MRI ice-water phantom to assess GD and effect of distortion in the measurement of ADC, respectively. Institutional review board approved the prospective clinical component of this study. DW-MRI data were obtained from 11 patients with head and neck cancer using these three DW-MRI methods. Wilcoxon signed-rank (WSR) and Kruskal–Wallis (KW) tests were used to compare ADC values, and qualitative rating by radiologist between three DW-MRI methods. In the ACR phantom, GD of 0.17% was observed for the b = 0 s/mm2 image of the MUSE-DWEPI with RPG method compared with that of 1.53% and 2.1% of MUSE-DWEPI and SS-DWEPI, respectively; The corresponding methods root-mean-square errors were 0.58, 3.37, and 5.07 mm. WSR and KW tests showed no significant difference in the ADC measurement between these three DW-MRI methods for both healthy masseter muscles and neoplasms (P > .05). We observed improvement in spatial accuracy for MUSE-DWEPI with RPG in the head and neck region with a higher correlation (R2 = 0.791) compared with that for SS-DWEPI (R2 = 0.707) and MUSE-DWEPI (R2 = 0.745). MUSE-DWEPI with RPG significantly reduces the distortion compared with MUSE-DWEPI or conventional SS-DWEPI techniques, and the ADC values were similar.

Highlights

Head and neck (HN) cancer is one of the most common types of cancer and results in >300 000 deaths per year worldwide [1]
The present study aims to compare the distortion-correction performance and apparent diffusion coefficient (ADC) values obtained from SS-DWEPI, multiplexed sensitivity encoding (MUSE)-DWEPI, and MUSEDWEPI with reverse-polarity gradient (RPG) methods in phantoms and patients
A geometric distortion (GD) of 0.17% was observed for the b = 0 s/mm2 image of MUSE-DWEPI with the RPG method along the phase-encoding directions compared with

Summary

Introduction

Head and neck (HN) cancer is one of the most common types of cancer and results in >300 000 deaths per year worldwide [1]. Standard MRI provides high-resolution anatomical images, whereas quantitative MRI techniques such as diffusion-weighted (DW)-MRI measure the Brownian motion of water molecules in tumor tissue, which is highly reflective of cellular organization and membrane integrity [8]. The apparent diffusion coefficient (ADC) derived from DW-MRI is a surrogate biomarker of tissue cellularity [9]. ADC is a useful prognostic and predictive biomarker in HN cancers [4, 15,16,17,18,19,20,21,22,23] and can help determine whether a posttreatment mass represents a scar tissue or a residual/recurrent tumor [24,25,26,27]. A recent review summarized the DW-MRI techniques, applications, and its limitations in HN cancer [28]

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