<b>SIMULATION AND FABRICATION OF WEARABLE AND STRETCHABLE RADIOFREQUENCY COILS FOR MRI</b>

<p dir="ltr">Magnetic resonance imaging (MRI) is a non-invasive, non-ionizing imaging modality that provides superior soft tissue contrast. MRI coils are magnetic field antennas that transmit and receive time-varying magnetic fields to and from the anatomical region of interest. The development of MRI coils has evolved over the past four decades from copper wire-based coils for mitigating coil losses to the recent introduction of wearable and stretchable technology. Stretchable coils enable expansion of the coil conductor to cover a region of interest with a reduced number of coil elements. However, the relation between signal-to-noise ratio (SNR) and the change in the receive magnetic field as a function of stretch is not known. This dissertation is regarding the simulation, design, fabrication, and validation of stretchable and wearable radiofrequency (RF) coils embedded directly on fabric for human and small animal MRI. The first aim involved determining the change in receive magnetic field, capacitance, inductance, SNR, and the underlying phantom area visualized using a fabric-based stretchable coil with electromagnetic simulations and in vitro experiments. The second aim involved the translation of stretchable MRI coils based on conductive threads for small animal imaging at 7T. A small animal stretchable coil was fabricated for rat spine and brain imaging at 7T to elucidate the benefits and limitations of the conductive thread method to develop wearable and stretchable MRI coils. The study also involved the development of open-source MRI hardware, such as preamplifiers for custom coil integration into the Bruker 7T scanner. The third aim was to overcome the limitations of the conductive thread method using conductive fabric with cutting plotters to develop wearable MRI coils. A conductive fabric neck array was developed for structural imaging of the cervical spine and 4D flow imaging of the carotid arteries at 3T. The fourth aim was to mitigate conductor losses in wearable coils through the application of copper foil directly on commercial fabric-based substrates to improve image quality for 3T musculoskeletal MRI. A shoulder array was developed using coil loops milled using a cutting plotter on a commercial fabric former. This work provides a new perspective on the design, fabrication, and validation of affordable and accessible wearable MRI coils through the integration of material engineering techniques into the development of MRI hardware.</p>