Abstract: Objective: To investigate the clinical value of Snapshot segment(or single sector reconstruction) combined with triphasic bolus injection in “Triple Rule-Out(TRO)" 64-row CT imaging for double-low scanning of chest pain. Methods: A total of 50 patients with acute chest pain who underwent 64-row CT imaging for TRO CT angiography(TRO-CTA) examination were randomly divided into two groups. All patients underwent retrospective ECG-gated chest TRO-CTA scanning. The heart rates ranged from 50 to 70 bmp. The body mass index(BMI) of the patients ranged from 18 to 28. Group A was identified as experimental group, which were underwent Snapshot segment reconstruction technique at the voltage of 100 kV, and received triphasic bolus contrast media injection at a volume of 60-70 mL. Patients in Group B were included as the control, which were underwent multi-sector reconstruction technique at the voltage of 120 kV, and received dualphasic bolus contrast media injection at a volume of 90-100 mL. The CT values and contrast noise ratio(CNR) of superior vena cava, pulmonary arteries, coronary arteries, and thoracic aorta between the two groups were compared. Besides, the image quality of pulmonary arteries and coronary arteries, and the radiation dose were compared. Results: There were significant differences in the CT values of superior vena cava, pulmonary arteries, coronary arteries, and thoracic aorta were detected between two groups with Student's test was used(P<0.05). There was statistical differences between the CT values of pulmonary arteries and veins in experimental group(P<0.05). No significant differences were found in the image quality, noise, or CNR between two groups(P>0.05), whereas the radiation dose in experimental group was significantly reduced by 40.19% when compared to that of in the control group(P<0.05). Conclusion: Snapshot segment combined with triphasic bolus injection technique could greatly reduce the contrast media and radiation dose as well as improved image quality, and it implied its great practicing value in the clinic.