Superselective pseudo-continuous arterial spin labeling angiography

Abstract

Purpose: To evaluate the utility of a novel non-contrast enhanced, vessel-selective magnetic resonance angiography (MRA) approach based on superselective pseudo-continuous arterial spin labeling (ASL) for the morphologic assessment of intracranial arteries when compared to a clinically used time-of-flight (TOF) MRA.

Materials and methods: Three sets of selective ASL angiographies (right and left internal carotid artery, basilar artery) as well as one TOF data set were obtained from each of the five volunteers included in this study on a clinical 1.5T system. The depiction of arterial segments as well as their delineation was evaluated and independently analyzed by two radiologists. Additionally, the ASL angiography approach was performed in two patients suffering from arterio-venous malformations (AVM) in order to illustrate potential applications in a clinical setting.

Results: In both angiography techniques, intracranial arteries and their segments (distal branches up to A5 segments of the anterior cerebral arteries, M8 segments of the middle cerebral arteries, and P5 segments of the posterior cerebral arteries) were continuously depicted with excellent inter-reader agreement (κ>0.81). In AVM patients, reconstructed images of the TOF angiography presented similar information about the size and shape of the AVM as did superselective ASL angiography. In addition, the acquired ASL angiograms of selected vessels allowed assessing the blood supply of individually labeled arteries to the AVM which could also be confirmed by digital subtraction angiography.

Conclusion: Superselective ASL angiography makes it possible to visualize arterial trees of selected vessels, thereby, providing information about the macrovascular blood supply and flow territories of intracranial arteries. Similar image quality is achieved when compared to clinically used TOF angiography with respect to the identification and delineation of arterial segments. Initial application of superselective ASL angiography in two patients with AVM's demonstrates the ability to gather additional important information about feeding vessels and blood supply.

Keywords: Arterial spin labeling; Arterio-venous malformation; MR angiography; Non-contrast enhanced; Selective ASL.