Dynamic MRI of swallowing: real-time volumetric imaging at 12 frames per second at 3 T

Luuk Voskuilen,Jasper Schoormans,Alfons J. M. Balm,Oliver J. Gurney-Champion,Gustav J. Strijkers,Ludi E. Smeele,Aart J. Nederveen

doi:10.1007/s10334-021-00973-6

Abstract

ObjectiveDysphagia or difficulty in swallowing is a potentially hazardous clinical problem that needs regular monitoring. Real-time 2D MRI of swallowing is a promising radiation-free alternative to the current clinical standard: videofluoroscopy. However, aspiration may be missed if it occurs outside this single imaged slice. We therefore aimed to image swallowing in 3D real time at 12 frames per second (fps).Materials and methodsAt 3 T, three 3D real-time MRI acquisition approaches were compared to the 2D acquisition: an aligned stack-of-stars (SOS), and a rotated SOS with a golden-angle increment and with a tiny golden-angle increment. The optimal 3D acquisition was determined by computer simulations and phantom scans. Subsequently, five healthy volunteers were scanned and swallowing parameters were measured.ResultsAlthough the rotated SOS approaches resulted in better image quality in simulations, in practice, the aligned SOS performed best due to the limited number of slices. The four swallowing phases could be distinguished in 3D real-time MRI, even though the spatial blurring was stronger than in 2D. The swallowing parameters were similar between 2 and 3D.ConclusionAt a spatial resolution of 2-by-2-by-6 mm with seven slices, swallowing can be imaged in 3D real time at a frame rate of 12 fps.

Highlights

Dysphagia or difficulty in swallowing is a potentially hazardous complication of diseases ranging from neurological disorders [1] to head-and-neck cancer [2]
We evaluated three acquisition patterns based on the stack-of-stars (SOS) by computer simulations, and by comparing the image quality provided by these patterns in a static phantom and in healthy volunteers
The images reconstructed using compressed sensing displayed a reduction in detail, which may have been caused by the broader PSF or the compressed-sensing regularisation (Fig. 2)

Summary

Introduction

Dysphagia or difficulty in swallowing is a potentially hazardous complication of diseases ranging from neurological disorders [1] to head-and-neck cancer [2]. Dysphagia can be classified either as a mechanical obstruction, for example the compression of the pharyngeal tract by a tumour mass, or as a motility disorder, often indicating a neuromuscular disease [3]. Oropharyngeal dysphagia may have a serious negative impact on the food intake [4], reducing the quality of life [5], and increases the chance of aspiration and subsequent pneumonia [6], which may be life threatening. The swallowing functionality of patients suffering from dysphagia should be monitored regularly. While the patient swallows a radiopaque contrast agent, a fluoroscope visualises the oral and pharyngeal phases of swallowing, and any aspiration of the contrast

Methods

Results

Conclusion