Arterial Spin Labeling Applications in Pediatric and Adult Neurologic Disorders

Abstract

Arterial spin labeling (ASL) is a powerful noncontrast magnetic resonance imaging (MRI) technique that enables quantitative evaluation of brain perfusion. To optimize the clinical and research utilization of ASL, radiologists and physicists must understand the technical considerations and age-related variations in normal and disease states. We discuss advanced applications of ASL across the lifespan, with example cases from children and adults covering a wide variety of pathologies. Through literature review and illustrated clinical cases, we highlight the subtleties as well as pitfalls of ASL interpretation. First, we review basic physical principles, techniques, and artifacts. This is followed by a discussion of normal perfusion variants based on age and physiology. The three major categories of perfusion abnormalities-hypoperfusion, hyperperfusion, and mixed patterns-are covered with an emphasis on clinical interpretation and relationship to the disease process. Major etiologies of hypoperfusion include large artery, small artery, and venous disease; other vascular conditions; global hypoxic-ischemic injury; and neurodegeneration. Hyperperfusion is characteristic of vascular malformations and tumors. Mixed perfusion patterns can be seen with epilepsy, migraine, trauma, infection/inflammation, and toxicmetabolic encephalopathy. Level of Evidence: 4 Technical Efficacy Stage: 3

Assessment of normalized cerebral blood flow and its connectivity with migraines without aura during interictal periods by arterial spin labeling

“…The results of ASL are consistent with PET and DSC, and ASL provides a brain CBF measurement with high reliability and repeatability [16,17]. Pseudo-continuous ASL (PCASL) can be used for whole-brain scanning and has a high clinical application value [14,15,18,19]. Most studies confirmed the detection of cerebral hypoperfusion in the acute phase of aura followed by rebound hyperperfusion [20,21] and hyperperfusion in the onset phase [22][23][24].…”

“…Research on perfusion imaging include the widely applied techniques of positron emission tomography (PET), CT perfusion, single photonemission computed tomography (SPECT), dynamic susceptibility contrast (DSC), magnetic resonance perfusion imaging and perfusion-weighted imaging (PWI) [11][12][13]. One of the non-invasive cerebral perfusion imaging techniques is arterial spin labeling (ASL), that can be utilized to quantitatively assess the degree of cerebral perfusion without having to apply a gadolinium-based contrast agent [14,15]. The results of ASL are consistent with PET and DSC, and ASL provides a brain CBF measurement with high reliability and repeatability [16,17].…”

Measuring brain beats: cardiac-aligned fast fMRI signals

“…MR angiography sequences provide insight into the integrity of the vascular anatomy either by the use of intravenous contrast to enhance blood signal, by designing sequences to manipulate the blood signal relative to be much darker than other tissue (black-blood), much brighter (bright-blood) (Nakao et al, 2018), or by introducing flow-sensitive encoding (phase-contrast) (Pelc, Bernstein, Shimakawa, & Glover, 1991). Arterial spin labeling quantitatively and noninvasively estimates brain perfusion with arterial blood water (Bambach, Smith, Morris, Campeau, & Ho, 2020; Telischak, Detre, & Zaharchuk, 2015).…”

Assessment of Modified Cerebral Blood Flow and Its Connectivity With Migraines Without Aura During Interictal Periods by Arterial Spin Labeling

“…Research on perfusion imaging include the widely applied techniques of positron emission tomography (PET), CT perfusion, single photon-emission computed tomography (SPECT), dynamic susceptibility contrast (DSC), magnetic resonance perfusion imaging and perfusion-weighted imaging (PWI) [11][12][13]. One of the non-invasive cerebral perfusion imaging techniques is arterial spin labeling (ASL), that can be utilized to quantitatively assess the degree of cerebral perfusion without having to apply a gadolinium-based contrast agent [14,15]. The results of ASL are consistent with PET and DSC, and ASL provides a brain CBF measurement with high reliability and repeatability [16,17].…”

“…This method adopts a fast spin echo sequence and helically lls the K space with higher resolution. It can be used for whole-brain scanning and has a high clinical application value [14,15,18,19]. Due to its hybrid nature, PCASL is the most commonly used sequence in modern ASL imaging [18,19].…”