Vessel-selective, non-contrast enhanced, time-resolved MR angiography with vessel-selective arterial spin labeling technique (CINEMA–SELECT) in intracranial arteries

Abstract

We demonstrate the feasibility of the vessel-selective, non-contrast, time-resolved magnetic resonance angiography (MRA) technique, "contrast inherent inflow enhanced multi-phase angiography combining vessel-selective arterial spin labeling technique (CINEMA-SELECT)". This sequence consists of two major techniques: pulsed star labeling of arterial regions (PULSAR) and Look-Locker sampling. We hypothesize that this technique allows selective labeling of single intracranial arteries, consisting of high-resolution four-dimensional data with a wide coverage of the brain. In this study, a new vessel-selective, time-resolved angiographic technique is demonstrated that can produce individual angiograms non-invasively by labeling the principal arterial vessels proximal to the circle of Willis. Clear vessel delineation is achieved, and the separation of the three vessels is evident in healthy volunteers. This technique could play an important role in the assessment of the structure and hemodynamics of intracranial arteries without the use of contrast agents.

3D time-resolved vessel-selective angiography based on pseudo-continuous arterial spin labeling

“…Usually, for time-resolved angiography images multi-phase acquisitions are performed [14,15,20,[22][23][24]. An adaptive method to achieve time resolved imaging could be to increase the labeling duration, which leads to visualization of vessel filling, but does not allow the visualization of a sharp bolus.…”

“…Magnetic Resonance Imaging xxx (2015) xxx-xxx For this purpose, often pulsed ASL methods are used, because a bolus of labeled blood is created by the inversion of a large blood volume at once, hence, allow to image the leading edge of the labeled blood bolus at the beginning of acquisition [15,20,[22][23][24]. In continuous ASL approaches, a blood bolus is created due to the continuous labeling of flowing blood, as a consequence, inverted blood spins may have already flown into the imaging slab at the time of data acquisition which makes it difficult to visualize the arrival of early blood spins.…”

“…Another commonly used method is RF spoiled gradient echo imaging (T1-TFE), which benefits from high SNR and is less susceptible to artifacts. Repetitive RF application combined with RF spoiling, however leads to loss of obtainable signal [24]. Optimization of specific imaging sequence parameters with respect to the used labeling technique or desired spatial and temporal resolution might improve the image quality and shorten the overall scan time to a minimum [14,20].…”

Superselective pseudo-continuous arterial spin labeling angiography

“…Scan parameter were as follows: FOV 220 × 220 × 90 mm 3 , 0.5 × 0.5 × 1.5 mm 3 , segmented 3D balanced Turbo Field Echo (b-TFE) acquisition, TFE factor 70, flip angle 90 • , and TR/TE 4.8/2.4 ms, resulting in a total measurement time of 4:30 per artery. The labeling duration was set to 1000 ms in order to ensure sufficient filling of intracranial vessels after spin tagging according to arterial transit times measured in [19,20]. Image acquisition started immediately after tagging with no effective post-labeling delay.…”

“…Time-resolved angiography methods would make it possible to visualize and measure the arterial transit times of the blood in an AVM and allow adapting the labeling duration accordingly. Such MR based approaches have already been proposed, but the selectivity of the labeling of such methods is restricted to larger vessels and acquisition times may increase with concurrent increase of spatial and time resolution [19,20,[32][33][34][35][36]. As opposed to DSA, MR based methods generally allow for the acquisition of different image contrasts and with identical location of the image stacks.…”