Time-efficient MRI and deuterium metabolic imaging (DMI) through parallel signal acquisition - PROJECT SUMMARY Deuterium metabolic imaging (DMI) is a novel, MR-based method to map metabolism non-invasively in vivo. DMI maps of glucose metabolism in patients with high grade brain tumors illustrate the detection of aberrant metabolism (`Warburg effect') with high contrast, thereby showing a strong clinical potential to supplement existing anatomical MRI with unique metabolic information. DMI is not the first MR-based metabolic imaging modality, but stands on the shoulders of 1H, 13C, 31P and hyperpolarized 13C MR spectroscopic imaging (MRSI). Unfortunately, none of these methods have reached their full clinical potential due to a variety of reasons including technical complexity and lack of robustness and/or sensitivity. DMI is unique in that it is extremely robust due to the simple MR acquisition methods, while providing good sensitivity and information content, making it an ideal technique for broad dissemination in the clinical arena. Yet, adding DMI scans to a standard, clinical MRI protocol is challenging because the relatively long scan time of DMI that can result in decreased patient compliance and increased scanning costs. Fortunately, MRI and DMI are based on different, well- separated resonance frequencies, opening the possibility to acquire DMI in parallel with MRI without increasing the scan time. This is achieved by implementing DMI acquisitions during the short delays present in most MRI methods to generate appropriate anatomical image contrast. Here we pursue the technological innovations necessary to achieve high-quality and time-efficient parallel acquisition of MRI and DMI on a clinical MR scanner. This overall goal will be achieved through three Aims, focused on hardware and software development followed by in vivo evaluation. Aim 1 is focused on the development of a 1H/2H RF coil suitable for parallel MRI-DMI on human brain in a clinical research setting. Primary design criteria are brain coverage and sensitivity for 1H and 2H, in addition to acceleration potential for 1H. Aim 2 addresses the development and implementation of parallel MRI-DMI methods on a clinical 3 T Siemens platform. The selected MRI methods will resemble a standard, clinical brain MR examination protocol and include FLAIR, T1-weighted MP-RAGE, diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI). Aim 3 is centered on a comparison between standard and parallel MRI-DMI acquisitions on healthy volunteers to test the general design philosophy that parallel MRI and DMI sensitivity, resolution and image contrast are unperturbed. Studies on patients with brain tumors are performed to demonstrate the robustness of parallel MRI-DMI under real-world conditions. Upon successful completion, this project will deliver the hardware and software necessary to achieve robust, parallel acquisition of high-quality MRI and DMI at 3 T. Integration of DMI into existing neuro MRI methods will result in a comprehensive imaging protocol that provides both standard anatomical and unique metabolic information of the brain without increased total scan time. These technical developments will be key for many clinical sites to gain access to DMI and drive its further development and validation via use in larger, diverse patient populations.
