Is Perfusion MRI without Deconvolution Reliable for Mismatch Detection in Acute Stroke? Validation with 15O-Positron...

Area of Science:

• Neuroimaging
• Radiology
• Stroke Medicine

Background:

• The mismatch concept in MR imaging is crucial for selecting acute stroke patients for reperfusion therapy.
• A controversy exists regarding the efficacy of deconvolved versus non-deconvolved perfusion-weighted (PW) parameter maps for predicting at-risk tissue.
• Optimal parameters and thresholds for guiding acute stroke treatment decisions remain debated.

Purpose of the Study:

• To validate non-deconvolved perfusion-weighted imaging (PWI) parameters against quantitative positron emission tomography (PET) for predicting penumbral flow (PF) in acute stroke.
• To assess the diagnostic accuracy of various non-deconvolved PWI parameters in identifying tissue at risk of infarction.

Main Methods:

• A cohort of 22 acute stroke patients underwent both MR and quantitative 15O-water PET imaging.
• Non-deconvolved PWI parameters were evaluated using receiver operating characteristic (ROC) curve analysis.
• The gold standard for PF detection was defined by PET-derived cerebral blood flow <20 mL/100 g/min.

Main Results:

• Normalized non-deconvolved parameters demonstrated significant accuracy in detecting the PF threshold.
• PW-first moment without delay correction (FM without DC) > 3.6 s (AUC = 0.89) showed high predictive value.
• PW-maximum of the concentration curve (Cmax) < 0.66 (AUC = 0.92) and PW-time to peak (TTP) > 4.0 s (AUC = 0.92) were highly accurate in identifying at-risk tissue.

Conclusions:

• Non-deconvolved PWI parameters, specifically FM without DC, Cmax, and TTP, are effective in predicting tissue at risk in acute stroke.
• These parameters provide observer-independent alternatives to established deconvolved parameters like Tmax.
• The findings support the use of these non-deconvolved parameters for guiding acute stroke treatment decisions.