Diseases of the cervical arteries, e.g., internal carotid artery (ICA) stenosis or occlusion, can lead to cerebral infarction and account for up to 20% of all acute ischemic stroke (AIS) [1]. Despite being considered the diagnostic standard of reference, digital subtraction angiography (DSA) inherits limitations and risks, including periinterventional neurologic complications in about 5% of patients [2]. Contrast-enhanced computed tomography (CTA) or magnetic resonance angiography (CE-MRA) enable a fast and non-invasive depiction of supraaortal arteries. Nevertheless, both are limited by the required application of intravenous contrast agent with associated drawbacks, including the risk of nephropathy in CTA [3], nephrogenic systemic fibrosis in CE-MRA [4] as well as allergic reactions [5] and potential mistiming of the acquisition of image data with respect to the contrast bolus for both imaging techniques [6].

Over the past decades, non-contrast-enhanced MRA (non-CE-MRA) techniques have gained growing interest in cardiovascular imaging [7,8]. In this context, 2D/3D time-of-flight (TOF)-MRA has been developed and is currently the most widely used technique for the intracranial arteries [7,8]. Nevertheless, its flow-dependency leading to overestimation of extracranial ICA stenosis and long acquisition time with susceptibility to motion artifacts limits its use for the imaging of cervical arteries [9,10]. Recently, the quiescent interval slice-selective (QISS)-MRA technique has been evaluated for the supraaortal arteries and shown promising results [[11], [12], [13]]. However, potential limitations, e.g., a 2D anisotropic acquisition, dependency of the vessel signal on the inflow of spins from outside the saturation volume, and an acquisition time of up to seven minutes restrict its use in clinical routine [14].

In 2019, Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) [15] has been introduced as a novel technique for flow-independent 3D isotropic non-CE-MRA and evaluated for the thoracic [[16], [17], [18], [19]] and pelvic [20] vasculatures. Albeit being unable to depict the intracranial ateries, the REACT sequence has also shown promising results for the imaging of supraaortal arteries with sufficient detection of extracranial ICA stenosis and adjacent plaques [[21], [22], [23]]. Nevertheless, a scan time of about three minutes still poses a risk of motion artifacts [21,22], especially in elderly or ill-conditioned patients. Additionally, a further decrease in scan time may expand its clinical application if the acquisition time is comparable to CE-MRA.

The purpose of this study was to evaluate a highly accelerated REACT sequence for rapid imaging of the supraaortal arteries in comparison to CE-MRA at 3 T. Therefore, a large cohort of patients with AIS was analyzed regarding subjective and objective image quality parameters as well as the assessability of ICA stenoses in both sequences.