Electromagnetic Simulation of Signal Distribution of Various RF Endoluminal Loop Geometries with Coil Orientation: Towards a Reconfigurable Design. (28th July 2021)

• Record Type: Journal Article
• Authors: Raki, Hamza; Tse Ve Koon, Kevin; Souchay, Henri; Robb, Fraser; Beuf, Olivier
• Other Names: Jouda Mazin Academic Editor.
• Is Part Of: Concepts in magnetic resonance. Volume 2021(2021)
• Publication Date: 2021-07-28
• Subjects: Magnetic resonance -- Periodicals; Nuclear magnetic resonance -- Periodicals; Biomedical engineering -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 538.36
• DOI: 10.1155/2021/6614696
• Languages: English
• ISSNs: 1552-5031

Abstract

Abstract : With the objective of improving MR endoluminal imaging of the colonic wall, electromagnetic simulations of different configurations of single-layer and double-layer, and double-turn endoluminal coil geometries were run. Indeed, during colon navigation, variations in coil orientation with respect to B0 are bound to occur, leading to impaired image acquisition due to a loss of signal uniformity. In this work, three typical coil orientations encountered during navigation were chosen and the resulting signal uniformity of the different geometries was investigated through the simulated B 1 x, y / I R t values. Sampling this quantity over a circle of radius r enabled us to calculate the coefficient of variation (= standard deviation/mean) for this given distance. This procedure was repeated for r ∈ 5 ; 15 mm, which represents the region of interest in the colon. Our results show that single-loop and double-layer geometries could provide complementary solutions for improved signal uniformity. Finally, using four microelectromechanical system switches, we proposed the design of a reconfigurable endoluminal coil able to switch between those two geometries while also ensuring the active decoupling of the endoluminal coil during the RF transmission of an MR experiment.