Integrating External Hardware on Existing Magnetic Resonance Systems for Commercially Unsupported Applications

Abstract

Magnetic resonance imaging and spectroscopy provide the potential for breakthroughs in the understanding of disease and evaluation of treatment outcomes in medical conditions such as muscular disorders, cancer, and mental illnesses. Compared to ¹H nuclei, secondary (non-¹H) nuclei such as ¹³C, ³¹P, and ²³Na necessitate higher sensitivity detection methods due to smaller concentrations in vivo and intrinsically lower Larmor frequencies. Two ways to increase the sensitivity of experiments using radiofrequency coils are 1) through optimizing the coil size to fit the volume of interest, and 2) through increasing the number of coils over a defined field of view through phased arrays. Clinical scanners are often constrained in these two regards in that the radiofrequency coils available from the vendor are generally much larger than the volume of interest, and clinical scanners are typically equipped with a singular broadband channel. With these limitations, there is a need to extend the capabilities of existing magnetic resonance systems to increase sensitivity for secondary nuclei and for imaging experiments that fall outside the characteristics of a typical human clinical exam (i.e. small samples, animals, or targeted anatomies).

This thesis describes a set of work to address these limitations in order to extend the capabilities of commercial scanners for custom applications. First, the functionality of an existing custom-built multi-channel, broadband receiver is improved through adding calibration capability on each individual channel and through the creation of a user interface that will result in a faster workflow which is critical for live animal experiments. Second, a custom-built double-tuned coil is interfaced to a 3T clinical magnetic resonance imaging system through a custom built connector, increasing the signal-to-noise ratio for the given application in comparison to the currently available coil for the scanner. Both of these projects work towards integrating external hardware on existing systems to increase the sensitivity of multinuclear studies and customized experiments.