Reliability of Pseudocontinuous Arterial Spin-Labeling in Ischemic Stroke and Comparison with Other Perfusion Techniques: Systematic Review and Meta-Analysis

Clinical Snapshot

Key Findings

• P Value: Not reported for primary outcome

• Effect Size: No significant differences in repeated CBF measurements (single low-quality study)

• Primary Outcome: Test-retest reliability of pCASL-derived CBF measurements

• Nnt Or Sensitivity: Excellent reliability across brain regions (single study finding)

• Confidence Interval: Infarct core relative CBF: 95% CI -0.11 to 0.13; Hypoperfusion volumes: 95% CI -0.28 to 0.68

Clinical Application

Limited by insufficient evidence base and need for specialized MRI sequences Relevant to Australian stroke centres with advanced MRI capabilities, but evidence insufficient to support routine clinical implementation over established DSC or CTP methods Patients with acute ischemic stroke requiring perfusion assessment

Abstract

BACKGROUND: Pseudocontinuous arterial spin-labeling (pCASL) is a noninvasive, gadolinium-free MRI technique for assessing brain perfusion. PURPOSE: The test-retest reliability of pCASL-derived CBF measurements in ischemic stroke (IS) were evaluated and pCASL metrics were compared with those from DSC, CTP, and PET. DATA SOURCES: Systematic searches were conducted in MEDLINE, EMBASE, and LILACS. Risk of bias and methodologic quality were evaluated using QUADAS-2 and Quality Appraisal for Reliability Studies tools. STUDY SELECTION: Eleven studies, encompassing 383 participants with IS were included. DATA ANALYSIS: Random-effects meta-analysis with inverse variance method and heterogeneity assessed using I 2 statistics were used. DATA SYNTHESIS: No PET studies were identified. Only 1 low-quality, high-risk-of-bias study assessed test-retest reliability, finding no significant differences in repeated absolute CBF measurements over time and excellent reliability across regions. Most studies comparing pCASL with DSC, and all comparing pCASL with CTP, had a low risk of bias. In the hyperacute phase of IS, pCASL and DSC showed no significant differences in infarct core relative CBF (95% CI, -0.11 to 0.13; I 2 = 0%) or hypoperfusion volumes (95% CI, -0.28 to 0.68; I 2 = 69%). Evidence on the comparability of pCASL with other DSC or CTP metrics was limited. LIMITATIONS: The small number of included studies prevented a meta-analysis for the primary outcome and limited conclusions for secondary outcomes. CONCLUSIONS: Robust conclusions about the test-retest reliability of pCASL or the comparability of metrics obtained with this technique and DSC, CTP, or PET in different phases after IS could not be drawn.

References

1. 1.Kroth, J. B., da Guarda, S. N. F., Wang, D. J. J., Martin, M. G. M., & Conforto, A. B. (2026). Reliability of pseudocontinuous arterial spin-labeling in ischemic stroke and comparison with other perfusion techniques: Systematic review and meta-analysis. AJNR American Journal of Neuroradiology. https://doi.org/10.1161/STROKEAHA.119.027457