Clinical Scorecard: Evaluating the Role of CT Perfusion as a Screening Method for Patients with Acute Stroke

At a Glance

Key Highlights

• CT perfusion (CTP) is widely used due to availability despite higher radiation compared to MRI perfusion (MRP).
• Automated CTP post-processing tools aid interpretation but have limitations including artifacts and lack of standardization.
• Emerging AI models on non-contrast CT and multiphase CT angiography may reduce reliance on CTP and radiation exposure.

Guideline-Based Recommendations

Diagnosis

• European Stroke Organization guidelines advise against perfusion imaging within 4.5 hours of symptom onset in witnessed stroke.
• Perfusion imaging is often used beyond guidelines to identify candidates for thrombectomy including wake-up strokes and extended windows.

Management

• Endovascular thrombectomy shows better outcomes in patients with large ischemic cores identified by imaging.
• Perfusion imaging assists detection of distal medium vessel occlusions difficult to identify on standard CTA or MRA.

Monitoring & Follow-up

• Radiologists must recognize factors affecting CTP data quality such as motion artifacts and suboptimal bolus timing.
• Careful interpretation of perfusion maps is required due to variability in post-processing algorithms and thresholds.

Risks

• CTP involves higher radiation doses compared to non-contrast CT and MRI perfusion.
• Overuse of CTP as a screening tool may expose patients to unnecessary radiation without clear diagnostic benefit.

Patient & Prescribing Data

Acute stroke patients undergoing imaging for diagnosis and treatment planning

CTP helps identify patients eligible for thrombolysis and thrombectomy, especially in extended time windows and wake-up strokes

Clinical Best Practices

• Prioritize MRI perfusion when available due to accuracy and lower radiation exposure.
• Use CTP judiciously, considering radiation risks and technical limitations.
• Develop expertise to identify artifacts and interpret perfusion data critically.
• Explore and integrate AI models for non-contrast CT and multiphase CTA to reduce radiation burden.
• Support research into optimizing MRI availability and portable MRI technologies.

References

• European Stroke Organization guidelines on perfusion imaging
• Studies on intravenous thrombolysis and mechanical thrombectomy efficacy
• Variability in perfusion post-processing algorithms
• Outcomes after thrombectomy in large ischemic core patients
• Ongoing trials on distal medium vessel occlusion thrombectomy
• AI model accuracy for early stroke detection on non-contrast CT
• Multiphase CT angiography for intracranial circulation assessment
• Evaluation of clot length with multiphase CTA
• Potential of multiphase CTA to derive perfusion parameters
• Portable MRI devices in stroke imaging