Prospective swallowing motion self-gating: a feasibility study in carotid artery wall MRI using 3D variable-flip-angle TSE

Abstract

Summary This preliminary study aimed to validate a self-gating method in combination with 3D TSE acquisition for gating swallowing motion. The effectiveness in reducing swallowing-related motion artifacts was demonstrated on healthy volunteers and patients. Background 3D black-blood MRI is a promising imaging modality for carotid artery wall imaging but is inherently susceptible to motion. Previous work shown that swallowing can result in the greatest motion at the carotid bifurcation and its vicinity (1). A self-gating (SG) method in combination with a 3D variable-flip-angle turbo spinecho sequence, SPACE, has recently been proposed for gating swallowing motion (2). This work aimed to validate the utility of the new technique on healthy volunteers and patients. Methods Imaging was performed on a 3T system (MAGNETOM Trio; Siemens) using a bilateral four-channel phased array carotid coil (Machnet BV). Eight healthy volunteers (3 M, 5 F, age 18-45 years) and 2 patients with carotid atherosclerosis (2 M, 67 and 74 years) were recruited in the study. All healthy subjects underwent the following three oblique coronal scans using the developed sequence: a) imaging without swallowing instructions or SG (“SPACE STL”); b) imaging with swallowing instructions but without SG (“SPACE SWL”); c) imaging with both swallowing instructions and SG ( “SPACE SWL+SG”). In the “SPACE SWL” and “SPACE SWL+SG” scans, subjects were instructed over the intercom to swallow twice at five preset stages, namely the 30th, 50th, 60th, 70th, and 90th TR of the scan ideally free of motion. The two patients underwent only two scans, SPACE without and with SG, without swallowing instructions. The relevant imaging parameters included: echo time (TE)/TR 141 msec/3 R-R intervals, ECG trigger delay 450-650 msec, readouts in the SI direction, voxel size (after interpolation) 0.35x0.36x0.36 mm3, acquisition time 120 TRs per scan in the absence of motion. Results