Abstract
Objective: Using 15O-H2O PET data, we developed a protocol to estimate myocardial blood flow (MBF) from dynamic multi-detector CT with low dose radiation exposure. Method: Twenty-two subjects underwent both dynamic CT and PET at rest and during stress. In 12 normal subjects (pilot group), the calculation for MBF with single compartment model was established. In the other 10 normal subjects (validation group), MBF estimated by CT and PET were compared. CT data were acquired at every heart beat for 20 seconds with ECG gated scan. Radiation exposure for each CT study was 9mSv to acquire 30 beats data. To develop a low exposure protocol, MBF were recalculated using skipped CT data for 1,2,3 and 4 beats interval. Result: In the pilot group, significant correlation was yielded between MBF from no-skipped CT data and PET (r=0.950, P<0.01). In the validation group, correlation between MBF from no-skipped CT and skipped CT for 1,2,3 and 4 beats interval were 0.995, 0.990, 0.983 and 0.953. MBF from 4 beats interval CT yielded low coefficient (P<0.01), at least 3 beats interval data is needed to estimate MBF by ECG gated CT. It reduces exposure to quarter compared with no-skipped CT.
