Prospective Evaluation of In Vivo and Phantom Repeatability and Reproducibility of Diffusion-Weighted MRI Sequences on 1.5 T MRI-Linear Accelerator (MR-Linac) and MR Simulator Devices for Head and Neck Cancers

Authors

Brigid A McDonald
Travis Salzillo
Samuel Mulder
Sara Ahmed
Alex Dresner
Kathryn Preston
Renjie He
John Christodouleas
Abdallah S R Mohamed
Marielle Philippens
Petra van Houdt
Daniela Thorwarth
Jihong Wang
Amita Shukla Dave
Michael Boss
Clifton D Fuller

Publication Date

8-1-2023

Journal

Radiotherapy & Oncology

Abstract

INTRODUCTION: Diffusion-weighted imaging (DWI) on MRI-linear accelerator (MR-linac) systems can potentially be used for monitoring treatment response and adaptive radiotherapy in head and neck cancers (HNC) but requires extensive validation. We performed technical validation to compare six total DWI sequences on an MR-linac and MR simulator (MR sim) in patients, volunteers, and phantoms.

METHODS: Ten human papillomavirus-positive oropharyngeal cancer patients and ten healthy volunteers underwent DWI on a 1.5 T MR-linac with three DWI sequences: echo planar imaging (EPI), split acquisition of fast spin echo signals (SPLICE), and turbo spin echo (TSE). Volunteers were also imaged on a 1.5 T MR sim with three sequences: EPI, BLADE (vendor tradename), and readout segmentation of long variable echo trains (RESOLVE). Participants underwent two scan sessions per device and two repeats of each sequence per session. Repeatability and reproducibility within-subject coefficient of variation (wCV) of mean ADC were calculated for tumors and lymph nodes (patients) and parotid glands (volunteers). ADC bias, repeatability/reproducibility metrics, SNR, and geometric distortion were quantified using a phantom.

RESULTS: In vivo repeatability/reproducibility wCV for parotids were 5.41%/6.72%, 3.83%/8.80%, 5.66%/10.03%, 3.44%/5.70%, 5.04%/5.66%, 4.23%/7.36% for EPI

CONCLUSION: MR-linac DWI sequences demonstrated near-comparable performance to MR sim sequences and warrant further clinical validation for treatment response assessment in HNC.

Keywords

Humans, Reproducibility of Results, Magnetic Resonance Imaging, Diffusion Magnetic Resonance Imaging, Head and Neck Neoplasms, Echo-Planar Imaging, Magnetic resonance imaging, Diffusion-weighted Imaging, MR-guided radiation therapy, MR-Linac, Test-retest, Apparent diffusion coefficient, Repeatability and reproducibility

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Associated Data

PMID: 37211282