Quantitative Dose Dependency Analysis of Whole-Brain CT Perfusion Imaging

Area of Science:

• Radiology
• Medical Imaging
• Neurology

Background:

• Cerebral CT perfusion imaging is crucial for diagnosing acute stroke.
• Radiation dose reduction is a key goal in medical imaging protocols.

Purpose of the Study:

• To evaluate the impact of decreased radiation dose on cerebral CT perfusion values in acute stroke patients.
• To determine the lowest effective radiation dose for accurate CT perfusion imaging.

Main Methods:

• Retrospective analysis of 20 ischemic stroke patients undergoing CT perfusion.
• Utilized a 320-detector row CT scanner with varying mAs settings to simulate dose reduction.
• Employed patient-specific digital perfusion phantoms to assess accuracy at reduced doses (0.5-5.0 mSv).

Main Results:

• At 2.5 mSv, mean differences in cerebral blood flow, volume, and transit time were within 5% of reference values.
• High correlation (0.864-0.917) was observed between reduced dose and reference perfusion values.
• No significant differences in perfusion values were found between the reference dose and the optimal reduced dose (2.5 mSv).

Conclusions:

• Clinical cerebral CT perfusion protocols can be safely reduced to 2.5 mSv.
• Minor quantitative effects on perfusion values are observed at 2.5 mSv.
• Dose reduction below 2.5 mSv may lead to overestimation of perfusion values, compromising diagnostic accuracy.