3D Time-Resolved Contrast-Enhanced MRA with Sliding Subtraction

T. A. Cashen, J. C. Carr, M. T. Walker, J. K. Hopkins, W. Shin, T. J. Carroll Biomedical Engineering, Northwestern University, Chicago, IL, United States, Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States Introduction Multi-phase angiography is necessary for the diagnosis of vascular disorders involving arteriovenous shunting, retrograde flow, and collateral circulation. Physicians typically employ X-ray digital subtraction angiography (DSA) to study the dynamic filling of vessels; however this technique is expensive, time-consuming, and invasive. A noninvasive technique would be preferable, yet other modalities currently cannot achieve adequate signal-to-noise ratio (SNR), spatial resolution, and temporal resolution. We present a MRA technique that could serve as an alternate to X-ray DSA in certain clinical scenarios. Time-resolved MRA has evolved considerably in recent years due to advances in scanner hardware and software. Much research has focused on the use of undersampling strategies to trade off SNR for spatial and temporal resolution (1-3). However, the primary goal of time-resolved MRA lately has been to acquire an arterial phase image without the need for timing the arrival of contrast. This technique goes one step further by imaging with fast enough temporal resolution to make the change between consecutive images imperceptible.