Ultra low contrast dose coronary computed tomography angiography one-beat acquisition: Opening door to patients

Background The role of 256 slices coronary computed tomography angiography (CCTA) one-beat acquisition in the evaluation of coronary arteries is well established, but the volume of the contrast media (CM) is a serious limitation of using this method in patients with severe comorbidities, specially in renal insufficiency. Reducing the dose of contrast would allow to expand indications to CCTA by reducing side effects of CM administration. Purpose To minimize contrast media volume in cardiac CT one-beat acquisition by optimizing injection protocols with maintaining the high image quality. Methods In total, 204 consecutive patients were enrolled and scanned on a 256-slices CT one-beat acquisition with standard tube voltage 120 kV. Patients were divided into two groups according to the injection protocols. Group A was scanned by using a standard three-phase injection protocol by using smart shot dual injector. Patients of group B underwent a new three-phase injection protocol with 63% CM dose reduction. Attenuation, image noise, signal-to-noise ratio (SNR) were calculated. Image quality was evaluated using 4-point Likert scale. Results The mean age was 61,5 ± 12,2, and 50,5% were males. The body mass index (BMI) was significantly lower in group B (28,1 ± 5,3 kg/m 2 vs. 24,4 ± 2,9 kg/m 2 respectively, P Mean amount of CM of group B was lowered by 63,1% on average when compared to group A (75,5 ± 4,7 ml in group A and 27,8 ± 5,6 ml in group B, P There were no significant differences in SNR (15,7 ± 3,4 vs. 14,9 ± 6,4, P  = 0,704) as well as in image quality between groups (3,8 ± 0,4 vs. 3,8 ± 0,37, P  = 0,85). Conclusion CCTA one-beat acquisition by using new injection protocol with 63% contrast media dose reduction maintain the high image quality of coronary arteries in patient with normal BMI. This 2,7 times contrast dose reduction opens the door and expands the boundaries for cardiac CT in patients with multiple comorbidities and renal insufficiency.