Non-contrast-enhanced 4D Intracranial MR Angiography with 4D NATIVE TrueFISP

Introduction: Conventional non-contrast-enhanced (NCE) MRA approaches including time-of-flight and phase contrast methods yield single frame static images or are limited in spatial resolution (typically by reverting to 2D rather than 3D methods) if multiphases ECG triggered acquisitions are used in the case of phase contrast. By administering T1-shortening contrast agents, timeresolved three-dimensional (4D) images can be acquired to depict morphological structure of vasculature as well as functional information of blood circulation. Typically temporal and spatial resolutions have to be compromised in order to synchronize data acquisition to the short first pass of contrast agent. While such tradeoff is acceptable for numerous applications, there are cases where both high spatial and temporal resolution are required in the same setting (e.g., to investigate the feeding and draining of blood into intracranial arterial-venous malformation). The purpose of this work was to develop a NCE 4D MRA technique providing both high spatial and temporal resolution images in the same measurement. The feasibility of such approach for intracranial MRA was validated in consecutive volunteer studies.