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

Area of Science:

• Cardiovascular imaging
• Radiology
• Medical physics

Background:

• Dynamic CT perfusion (CTP) offers combined anatomical and functional assessment.
• High radiation dose is a limitation of current CTP methods.
• Reducing radiation exposure is crucial for patient safety and broader clinical adoption.

Purpose of the Study:

• To evaluate the feasibility of reducing radiation dose in dynamic CTP.
• To assess the accuracy of myocardial blood flow (MBF) quantification with reduced data acquisition rates.
• To determine if a lower sampling rate maintains diagnostic equivalence for ischemic heart disease evaluation.

Main Methods:

• Dynamic CTP performed on 56 patients with suspected ischemic heart disease.
• Post hoc construction of datasets with reduced sampling rates (2 and 3 RR-intervals).
• Comparison of MBF estimates from reduced datasets (2RR, 3RR) against the full dataset (1RR) using equivalence testing.

Main Results:

• Significant equivalence found for rest MBF, stress MBF, and coronary flow reserve (CFR) when comparing 2RR to 1RR datasets (p < 0.001 for MBF, p = 0.005 for CFR).
• The 2RR reconstruction protocol demonstrated an estimated radiation dose reduction of 35.4% ± 3.8%.
• MBF quantification is achievable with a sampling rate of one volume per two heartbeats.

Conclusions:

• Dynamic CTP can accurately quantify MBF using a reduced heart rate sampling strategy.
• This optimized sampling approach significantly reduces radiation dose.
• The findings support the clinical utility of lower-dose CTP for diagnosing ischemic heart disease.