Balanced SSFP Spin-Labeled Angiography Using Sparse Data: Optimization and Application to Supraaortic Vessels

Introduction: Although contrast-enhanced magnetic resonance angiography (CE-MRA) remains the technique of choice for evaluating the blood vessels of the head and neck, it is now frequently contraindicated in patients with renal insufficiency at risk for nephrogenic systemic fibrosis. Pulsed arterial spin-labeled (ASL) angiography has long been proposed as a method for unenhanced MRA [1] that may provide better contrast than wellestablished unenhanced methods of 2D and 3D time-of-flight (TOF) angiography. Due to the presence of flow artifacts in stenotic vessels containing rapid blood flow, however, it remains challenging to robustly combine the pulsed ASL method with a balanced steady-state free precession (bSSFP) readout. Here we sought to optimize a 3D bSSFP-based pulsed ASL technique in a flow phantom, and apply the optimized technique to image the carotid and intracranial arteries. Furthermore, the technique was based on sparse data to improve parallel imaging reconstruction quality [2].