Lu, Ming; Li, Pingping; Moore, Jason E.; Jiang, Xiaoyu; Gore, John C.; & Yan, Xinqiang. (2026). Coaxial capacitor (COCA) coil for stretchable arrays in ultrahigh-field MRI. AIP Advances, 16(1), 15129. https://doi.org/10.1063/5.0304790
Stretchable radiofrequency (RF) coils could improve MRI scans by fitting closely to a patient’s body, enhancing both image quality and comfort. In this study, we explore a stretchable receive array based on the coaxial capacitor (COCA) coil for 7 T MRI, made mainly from ultra-flexible Litz wire stitched onto elastic fabric. The COCA design removes the need for traditional capacitors and keeps stable performance even when stretched, as long as the coil’s overlapped and overall areas stretch proportionally. Tests on bench setups and phantom models show that elliptical COCA coils maintain consistent behavior up to 1.3× stretching and provide better signal-to-noise ratio than fixed coils across different phantom sizes. This design shows strong promise for wearable coil arrays, offering better imaging quality and adaptability to different body shapes.
Fig 1: (A) Circuit diagram and (B) photograph of a single 10-cm-diameter coaxial capacitor coil designed for 7 T MRI. The exceptional flexibility of the Litz wire, which forms the majority of the coil, is demonstrated by its ability to bend around a rod as thin as 1.6 mm (C).