Comparison of 10 TTP and Tmax estimation techniques for MR perfusion-diffusion mismatch quantification in acute...

Area of Science:

• Neuroradiology
• Acute Stroke Imaging
• Cerebrovascular Disease

Background:

• Perfusion and diffusion MRI mismatch identifies tissue at risk of infarction in acute stroke.
• Variability in mismatch volume estimation can affect clinical decision-making.

Purpose of the Study:

• To analyze the variability of mismatch volumes derived from different time-to-peak (TTP) or time-to-maximum (Tmax) estimation techniques.
• To assess the impact of these variations on the classification of patients with acute stroke.

Main Methods:

• Analysis of 50 middle cerebral artery stroke patients imaged within 6 hours of symptom onset.
• Utilized 10 distinct TTP/Tmax techniques with varying delay thresholds (+2 to +12 seconds) for perfusion lesion calculation.
• Semiautomatically segmented diffusion lesions and registered them for mismatch quantification.

Main Results:

• Observed mean volumetric differences up to 40-100 mL between mismatch volumes calculated by different TTP/Tmax methods.
• Clinically relevant mismatch classification varied in up to 24% of cases depending on the TTP/Tmax estimation technique used.
• Significant variability in tissue-at-risk volume estimation was demonstrated.

Conclusions:

• High variations in tissue-at-risk volumes are expected with different TTP/Tmax estimation techniques.
• Standardization or correction formulas are needed for comparable study results in acute stroke assessment.
• Addressing methodological variability is crucial for reliable clinical interpretation of perfusion-diffusion mismatch.