Multi-Echo Flow-encoded Rosette (MELROSE) enables velocity and T2* assessment of both extravascular tissue and intravascular blood for motion robust, quantitative cardiovascular blood flow and oxygenation mapping


Adam Bush, Christopher Sandino, Marcus Alley, Shreyas Vasanawala

Cardiovascular Cardiac catheterization is an invasive albeit common procedure performed in children with congenital heart disease for intrathoracic oxygen saturation assessment, exposing patients to anesthesia and risk of infection and complication. Prior MRI based intrathoracic oximetry methods have been limited due to partial volume contamination of the blood pool with surrounding tissue and motion corruption. Recently, subtractive MRI oximetry methods have demonstrated reliability and robustness but are limited to Cartesian strategies in the brain. In this work we use a subtractive, velocity encoded, non-Cartesian rosette trajectory for quantitative, motion robust, extra and intravascular flow and T2* mapping entitled Multi Echo fLowencoded ROSEtte (MELROSE). We validate flow and T2* values in a flow phantom and present preliminary results in a healthy subject. Theory Rosette trajectories are flower-like k-space traversal patterns first described by Noll. Rosette trajectories have several advantages over spiral and radial sequences, including higher average gradients and improve incoherence for compressed sensing application yet remain largely unused. In this work, we use a novel rosette shape parameterization, q. Each repetition time, a “flower” is acquired, representing a highly undersampled k-space acquisition. By performing a multi-shot sequence and incrementing successive flowers by the golden angle (137.5°) a fully sampled data set can be acquired. Recombination of individual petals, or samples between temporally adjacent center crossings, allows for multi-echo reconstructions... Abstract truncated


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