Off-resonance artifact correction for magnetic resonance imaging: a review

TL;DR

This review discusses the causes and effects of off-resonance artifacts in MRI, and reviews strategies for correction, emphasizing recent advances and challenges in low-field and portable MRI applications.

Contribution

It provides a comprehensive overview of off-resonance sources, effects, and correction methods, including recent developments and the specific challenges faced in low-field MRI.

Findings

Off-resonance causes signal loss, distortions, and blurring in MRI images.

Recent correction strategies improve image quality in clinical and portable MRI.

Low-field MRI presents unique advantages and challenges regarding off-resonance artifacts.

Abstract

In magnetic resonance imaging (MRI), inhomogeneity in the main magnetic field used for imaging, referred to as off-resonance, can lead to image artifacts ranging from mild to severe depending on the application. Off-resonance artifacts, such as signal loss, geometric distortions, and blurring, can compromise the clinical and scientific utility of MR images. In this review, we describe sources of off-resonance in MRI, how off-resonance affects images, and strategies to prevent and correct for off-resonance. Given recent advances and the great potential of low field and/or portable MRI, we also highlight the advantages and challenges of imaging at low field with respect to off-resonance.