Optimization of image sampling rate to lower the radiation dose of dynamic myocardial CT perfusion.

BACKGROUND

Dynamic myocardial CT perfusion (CTP) has emerged as a potential strategy to combine anatomical and functional evaluation in a single modality. However, this method results in a high radiation dose.

METHODS

Dynamic CTP was performed in 56 patients with suspected or known ischemic heart disease of whom 48 had complete CT-data. Datasets with reduced sampling rate of 2- and 3 RR-intervals (2RR and 3RR) were constructed post hoc. Myocardial blood flow (MBF) estimates from the 2RR and 3RR datasets were compared with estimates based on the full dataset (1RR) using the two one-sided test of equivalence for paired samples.

RESULTS

Significant equivalence was found for rest MBF (p ​< ​0.001), stress MBF (p ​< ​0.001) and for the CFR (p ​= ​0.005) when comparing 2RR blood flow estimates with the results based on the 1RR dataset. The 2RR reconstruction protocol led to an estimated reduction in radiation dose of 35.4 ​± ​3.8%.

CONCLUSION

MBF can be quantitated with dynamic CTP using a sampling strategy of one volume for every second heartbeat. This strategy could lead to a significant reduction in radiation dose.