Wide-Detector CT-Based optimized triple Rule-Out CT angiography for emergency chest pain: reducing contrast and radiation without compromising diagnostic quality.

Background: The triple rule-out computed tomography angiography (TRO-CTA) has recently emerged as a technique that noninvasively evaluates the coronary arteries (CAs), the pulmonary arteries (PAs) and the thoracic aorta (TA).

Objective: To evaluate the feasibility of an optimized scanning protocol to reduce the volume of iodine contrast media (ICM), injection rate, and radiation dose in patients undergoing TRO-CTA.

Methods: Patients undergoing TRO-CTA were assigned to either group A or group B using a 16 cm wide-detector CT. Patients in group A were imaged with a traditional triple scanning protocol with a sequence of the PA, CAs, and TA. Patients in group B were imaged using the modified protocol with scanning sequence of PA, TA, and CAs, ICM of 55 ml, and injection rate of 4.5 mL/s. The image quality and effective radiation dose (ED) were compared.

Results: There were no significant differences in basic information between groups A and B. Other than the left PA, RA, and RV, there were no significant differences in the CT attenuation values of relevant vascular structures between groups A and B. There were no significant differences in CNR values between the two groups except the LAD-D and LCX. The image quality scores were comparable between groups A and B except the CAs. However, there were significant differences between the two groups in ICM (p < 0.05), scanning time (p < 0.001) and ED (p = 0. 023).

Conclusions: The optimized TRO-CTA scanning protocol can achieve less ICM and lower ED while maintaining image quality.