Coronary computed tomography angiography using ultra-low-dose contrast media: radiation dose and image quality

Abstract Background The major concerns with coronary computed tomography angiography (CCTA) is the amount of contrast media (CM) injected and the radiation dose. Purpose To establish low radiation CCTA with low amount of contrast media. Methods Consecutive 60 patients (body weight ≤70mg or less and Agatston score ≤400) who were scheduled coronary computed tomography angiography were enrolled. Dual-source scanner (SOMATOM Force, Siemens, Germany) was used and CM used was Iopamidol 370mg/I (Bayer, Germany). Coronary CT angiography was performed with Turbo Flash Spiral and Sinogram Affirmed Iterative Reconstruction was done. The dose of contrast media was decided according to our original predicting system for 300HU. This study was approved by the local ethics committee and all patients gave written, informed consent. Exclusion criteria for CCTA were low Agatston score (<50), atrial fibrillation, allergy to CM, renal insufficiency (glomerular filtration rate <60 mL/min/1.73 mm2), pregnancy, congenital heart disease, low left ventricular function, and coronary artery bypass graft. All segments were evaluated using a 5-point scale: 5, excellent and easily assessable,; 4, good, mild artifacts at 1 segment and assessable; 3, evaluable, moderate artifacts on a few segments; 2, evaluable, diagnostic combined with axial images; and 1, not assessable. Results All patients successfully performed CCTA. Age averaged 46±15 yo (mean±S.D.) and body mass index averaged 22.5±3.0. Used CM was 12±7ml and intracoronary CT number 329±28HU. Dose-length product averaged 21.7±15.0 mGy cm and effective dose averaged 0.30±0.21mSv. Image quality averaged 4.8±0.7. CCTA with the lowest effective dose was 0.04mSv and CCTA with the lowest CM was 4ml. Conclusions Ultra-low dose 70kV-CCTA with low dose of contrast media can be performed using dual source computed tomography in patients with body weight ≤70mg or less and Agatston score ≤400.

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Comparison of image quality and radiation dose using different pre-ASiR-V and post-ASiR-V levels in coronary computed tomography angiography

Journal of X-Ray Science and Technology ◽

10.3233/xst-200754 ◽

2020 ◽

pp. 1-10

Author(s):

Yongxia Zhao ◽

Dongxue Li ◽

Zhichao Liu ◽

Xue Geng ◽

Tianle Zhang ◽

...

Keyword(s):

Computed Tomography ◽

Image Quality ◽

Radiation Dose ◽

Computed Tomography Angiography ◽

Coronary Computed Tomography Angiography ◽

Effective Radiation Dose ◽

Dose Length Product ◽

Coronary Computed Tomography ◽

Significant Difference ◽

Noise Ratio

OBJECTIVE: To determine the optimal pre-adaptive and post-adaptive level statistical iterative reconstruction V (ASiR-V) for improving image quality and reducing radiation dose in coronary computed tomography angiography (CCTA). METHODS: The study was divided into two parts. In part I, 150 patients for CCTA were prospectively enrolled and randomly divided into 5 groups (A, B, C, D, and E) with progressive scanning from 40% to 80% pre-ASiR-V with 10% intervals and reconstructing with 70% post-ASiR-V. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was assessed using a 5-point scale. The CT dose index volume (CTDIvol) and dose-length product (DLP) of each patient were recorded and the effective radiation dose (ED) was calculated after statistical analysis by optimizing for the best pre-ASiR-V value with the lowest radiation dose while maintaining overall image quality. In part II, the images were reconstructed with the recommended optimal pre-ASiR-V values in part I (D group) and 40%–90% of post-ASiR-V. The reconstruction group (D group) was divided into 6 subgroups (interval 10%, D0:40% post-ASiR-V, D1:50% post - ASiR-V, D2:60% post-ASiR-V, D3:70% post-ASiR-V, D4:80% post-ASiR-V, and D5:90% post-ASiR-V).The SNR and CNR of D0-D5 subgroups were calculated and analyzed using one-way analysis of variance, and the consistency of the subjective scores used the k test. RESULTS: There was no significant difference in the SNRs, CNRs, and image quality scores among A, B, C, and D groups (P > 0.05). The SNR, CNR, and image quality scores of the E group were lower than those of the A, B, C, and D groups (P < 0.05). The mean EDs in the B, C, and D groups were reduced by 7.01%, 13.37%, and 18.87%, respectively, when compared with that of the A group. The SNR and CNR of the D4–D5 subgroups were higher than the D0-D3 subgroups, and the image quality scores of the D4 subgroups were higher than the other subgroups (P < 0.05). CONCLUSION: The wide-detector combined with 70% pre-ASiR-V and 80% post-ASiR-V significantly reduces the radiation dose of CCTA while maintaining overall image quality as compared with the manufacture’s recommendation of 40% pre-ASiR-V.

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Low Dose versus Standard Single Heartbeat Acquisition Coronary Computed Tomography Angiography

Journal of Clinical Imaging Science ◽

10.4103/jcis.jcis_51_18 ◽

2018 ◽

Vol 8 ◽

pp. 52

Author(s):

Ernesto Di Cesare ◽

Alessandra Di Sibio ◽

Antonio Gennarelli ◽

Margherita Di Luzio ◽

Ines Casazza ◽

...

Keyword(s):

Computed Tomography ◽

Comparative Analysis ◽

Image Quality ◽

Radiation Dose ◽

Effective Dose ◽

Computed Tomography Angiography ◽

Coronary Computed Tomography Angiography ◽

Ct Scanner ◽

Diagnostic Quality ◽

Coronary Computed Tomography

Purpose: The aim of this study was to compare image quality and mean radiation dose between two groups of patients undergoing coronary computed tomography angiography (CCTA) using a 640-slice CT scanner with two protocols with different noise level thresholds expressed as standard deviation (SD). Materials and Methods: Two-hundred and sixty-eight patients underwent a CCTA with 640 slice CT scanner. In the experimental group (135 patients), an SD 51 protocol was employed; in the control group (133 patients), an SD 33 protocol was used. Mean effective dose and image quality with both objective and subjective measures were assessed. Image quality was subjectively assessed using a five-point scoring system. Segments scoring 2, 3, and 4 were considered having diagnostic quality, while segments scoring 0 and 1 were considered having nondiagnostic quality. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) between the two groups as well as the effective radiation dose (ED) was finally assessed. Results: Comparative analysis considering diagnostic quality (2, 3, and 4 score) and nondiagnostic (score 0 and 1) quality demonstrated that image quality of SD 51 group is not significantly lower than that of S33 group. The noise was significantly higher in the SD 51 group than in the SD 33 group (P < 0.0001). The SNR and CNR were higher in the SD 33 group than in SD 51 group (P < 0.0001). Mean effective dose was 49% lower in the SD 51 group than in SD 33 group; indeed mean effective dose was 1.43 mSv ± 0.67 in the SD 51 group while it was 2.8 mSv ± 0.57 in the SD 33 group. Conclusion: Comparative analysis shows that using a 640-slice CT with a 51 SD protocol, it is possible to reduce the mean radiation dose while maintaining good diagnostic image quality.

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