High-resolution imaging of the excised porcine heart at a whole-body 7 T MRI system using an 8Tx/16Rx pTx coil

• Published in: Magma (New York, N.Y.) N.Y.), 2023-04, Vol.36 (2), p.279-293
• Main Authors: Terekhov, Maxim, Elabyad, Ibrahim A., Lohr, David, Hofmann, Ulrich, Schreiber, Laura M.
• Format: Article
• Language: English
• Subjects: Animals; Artificial Intelligence; Basic Science - Cardio-vascular; Biomedical Engineering and Bioengineering; Computer Appl. in Life Sciences; Diffusion Tensor Imaging; Equipment Design; flow and angiographic imaging techniques; Health Informatics; Imaging; Magnetic Resonance Imaging - methods; Medicine; Medicine & Public Health; Phantoms, Imaging; Radiology; Research Article; Signal-To-Noise Ratio; Solid State Physics; Swine
• ISSN: 1352-8661; 0968-5243; 1352-8661
• DOI: 10.1007/s10334-023-01077-z

Introduction MRI of excised hearts at ultra-high field strengths ( B 0 ≥7 T) can provide high-resolution, high-fidelity ground truth data for biomedical studies, imaging science, and artificial intelligence. In this study, we demonstrate the capabilities of a custom-built, multiple-element transceiver array customized for high-resolution imaging of excised hearts. Method A dedicated 16-element transceiver loop array was implemented for operation in parallel transmit (pTx) mode (8Tx/16Rx) of a clinical whole-body 7 T MRI system. The initial adjustment of the array was performed using full-wave 3D-electromagnetic simulation with subsequent final fine-tuning on the bench. Results We report the results of testing the implemented array in tissue-mimicking liquid phantoms and excised porcine hearts. The array demonstrated high efficiency of parallel transmits characteristics enabling efficient pTX-based B 1 + -shimming. Conclusion The receive sensitivity and parallel imaging capability of the dedicated coil were superior to that of a commercial 1Tx/32Rx head coil in both SNR and T 2 *-mapping. The array was successfully tested to acquire ultra-high-resolution (0.1 × 0.1 × 0.8 mm voxel) images of post-infarction scar tissue. High-resolution (isotropic 1.6 mm 3 voxel) diffusion tensor imaging-based tractography provided high-resolution information about normal myocardial fiber orientation.