Efficacy of arterial spin labeling for detection of the ruptured micro-arteriovenous malformation: illustrative cases

Arterial Spin Labeling: Key Concepts and Progress Towards Use as a Clinical Tool

Arterial spin labeling (ASL), a non-invasive MRI technique, has emerged as a valuable tool for researchers that can measure blood flow and related parameters. This review aims to provide a qualitative overview of the technical principles and recent developments in ASL and to highlight its potential clinical applications. A growing literature demonstrates impressive ASL sensitivity to a range of neuropathologies and treatment responses. Despite its potential, challenges persist in the translation of ASL to widespread clinical use, including the lack of standardization and the limited availability of comprehensive training. As experience with ASL continues to grow, the final stage of translation will require moving beyond single site observational studies to multi-site experience and measurement of the added contribution of ASL to patient care and outcomes.

Current and Future Applications of Arterial Spin Labeling MRI in Cerebral Arteriovenous Malformations

Arterial spin labeling (ASL) has emerged as a promising noninvasive tool for the evaluation of both pediatric and adult arteriovenous malformations (AVMs). This paper reviews the advantages and challenges associated with the use of ASL in AVM assessment. An assessment of the diagnostic workup of AVMs and their variants in both adult and pediatric populations is proposed. Evaluation after treatments, whether endovascular or microsurgical, was similarly examined. ASL, with its endogenous tracer and favorable safety profile, offers functional assessment and arterial feeder identification. ASL has demonstrated strong performance in identifying feeder arteries and detecting arteriovenous shunting, although some studies report inferior performance compared with digital subtraction angiography (DSA) in delineating venous drainage. Challenges include uncertainties in sensitivity for specific AVM features. Detecting AVMs in challenging locations, such as the apical cranial convexity, is further complicated, demanding careful consideration due to the risk of underestimating total blood flow. Navigating these challenges, ASL provides a noninvasive avenue with undeniable merits, but a balanced approach considering its limitations is crucial. Larger-scale prospective studies are needed to comprehensively evaluate the diagnostic performance of ASL in AVM assessment.

Efficacy of repeat arterial spin labeling for angiogram-negative ruptured micro-arteriovenous malformation: A case report

Background:

Diagnosing ruptured micro-arteriovenous malformation (AVM) could be difficult using digital subtraction angiography (DSA) in the acute stage, and a repeat DSA is recommended in DSA-negative cases. Arterial spin labeling (ASL) is a useful noninvasive tool for detecting AVM, but the efficacy of a repeat ASL for DSA and ASL-negative ruptured micro-AVM in the acute stage is unclear. Here, we report a case of ruptured micro-AVM that was not detected in the acute stage by ASL but in the chronic stage by ASL.

Case Description:

A 43-year-old man developed right upper-extremity paralysis, and computed tomography (CT) revealed a left frontal lobe hemorrhage. Magnetic resonance imaging, including ASL, CT angiography, and DSA, showed no abnormal findings associated with hemorrhage in the acute stage. The second ASL 93 days after the hemorrhage showed a high signal on the cortical vein of the left frontal lobe and superior sagittal sinus, and subsequent DSA detected a micro-AVM in the left precentral gyrus.

Conclusion:

Repeat ASL is less invasive and useful for detecting micro-AVMs which showed no findings on ASL and DSA in the acute stage.