Highly Accelerated Pulmonary MRI Using RF Depolarization of 129Xe: The Sectoral Pulse Sequence

Motivation: Lung MRI using hyperpolarized 129Xe is an important but expensive diagnostic tool for various pulmonary diseases. Reducing scan times and the xenon dose required for a clinically-viable lung image would drastically lower the barrier to entry for pulmonary imaging. Goal(s): We intend to use the RF depolarization of xenon to accelerate lung images and reduce the required amount of inhaled 129Xe. Approach: Various sampling schemes for the Sectoral pulse sequence are developed and compared with the gradient echo sequence. Results: The proposed method, coupled with the short-Sectoral sampling scheme, allows for aggressive undersampling with a third of a typical xenon dose. Impact: We present a significant acceleration method which uses RF depolarization of hyperpolarized gas in lungs to reduce 129Xe dose costs. This method results in clinically-viable lung images with up to 10-fold acceleration possible with a 3-fold reduction in 129Xe dose.