Perfusion stability in acute stroke: An observational study exploiting repeated CTP imaging.

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• CT perfusion (CTP) is crucial for assessing infarct core in acute stroke.
• Limited real-world data exists on CTP reproducibility and temporal dynamics.

Purpose of the Study:

• To evaluate the reproducibility and temporal consistency of CTP metrics in acute stroke patients.
• To assess scan-to-scan variability in infarct core and hypoperfusion volumes.

Main Methods:

• Retrospective analysis of repeated CTP scans in acute stroke patients.
• Quantification of infarct core and hypoperfusion volumes using standard thresholds.
• Bland-Altman analysis to assess scan-to-scan differences and their association with time intervals.

Main Results:

• No significant systematic bias was observed at the group level for infarct core or hypoperfusion volumes.
• Substantial variability was noted in individual measurements, but intensity metrics showed lower variability than volume estimates.
• High correlations were found for core volume, hypoperfusion volume, and ASPECTS between scans, with no association with scan interval.

Conclusions:

• Repeated CTP demonstrates temporal consistency at the group level, with minimal systematic bias.
• Intensity-based CTP metrics exhibit lower variability than volume estimates.
• Findings question the direct application of linear infarct growth rate models to CTP, which reflects hemodynamic status.