Accuracy of Myocardial Blood Flow Estimation From Dynamic Contrast-Enhanced Cardiac CT Compared With PET

Area of Science:

• Cardiovascular imaging
• Radiology
• Medical diagnostics

Background:

• Assessing absolute myocardial blood flow (MBF) using dynamic contrast-enhanced cardiac computed tomography (CT) requires further characterization.
• Comparison with rubidium-82 positron emission tomography (PET) is crucial for validating CT accuracy.

Purpose of the Study:

• To evaluate the accuracy of absolute myocardial blood flow (MBF) estimates derived from dynamic contrast-enhanced cardiac CT.
• To compare CT-derived MBF with rubidium-82 PET MBF in a high-risk patient population.

Main Methods:

• A prospective trial involving 34 high-risk patients undergoing clinically indicated rubidium-82 PET scans.
• Dynamic contrast-enhanced cardiac CT scans were acquired during rest and stress phases.
• Global MBF was calculated from both PET and CT datasets for comparison.

Main Results:

• CT-derived global MBF showed high correlation with PET MBF (r=0.92, P<0.001).
• CT MBF estimates were within 20% of PET estimates (P<0.02).
• Myocardial flow reserve was underestimated by CT (-14±28%).

Conclusions:

• Clinically practical dynamic contrast-enhanced cardiac CT offers unbiased MBF estimates comparable to rubidium-82 PET in high-risk patients.
• CT MBF estimates exhibit significant variance, and myocardial flow reserve estimation is less accurate than individual MBF.
• The protocol's effective dose was approximately 8.4±1.1 mSv.