High Resolution Dynamic Susceptibility Contrast Perfusion Imaging Using Multi-Echo Spirals and Temporal Compressed Sensing-Based Reconstruction

Introduction: Dynamic susceptibility contrast (DSC) perfusion weighted MRI (PWI) is a widely used approach for measuring haemodynamic perfusion parameters, such as cerebral blood volume/flow (CBV/CBF) and mean transit time (MTT). These quantitative maps reveal clinically relevant information for treatment of stroke and brain tumor patients that may not be obtained with regular MRI exams. The perfusion parameters are derived from changes in signal-time course of injected contrast agent, with most important information obtained over a span of 10-20 sec [1], necessitating very rapid time-resolved imaging, which requires tradeoffs with spatial resolution (typically,128x128 in-plane). While more accurate models for parameter estimation have been developed, the available imaging techniques often are unable to provide sufficient input to models (e.g., limited resolution reduces accuracy of arterial input function (AIF) calculation). Traditionally used single shot echoplanar imaging (EPI) decreases spatial resolution further due to T2 signal decay during long readout accompanied by significant geometric distortions. Segmented acquisition at multiple echo times and subsequent R2 mapping for quantification [1] can minimize some EPI artifacts and provide insensitivity to T1 effects at the expense of further reduction of temporal and spatial resolution. In this work, we present a novel approach to high resolution DSC PWI, which utilizes a combination of compressed sensing (CS)-type reconstruction with efficient multi-echo spiral acquisition.