Reduced of radiation exposure and iodine load at CT angiography of the aorta before aortic and aortic valve replacement surgery

Objective. The comparison of protocols of computed tomography (CT) angiography of the aorta and their modification in conditions of radiation and iodine load reducing on the patient.
Methods. In 95 patients (57 men, 38 women, mean age 61.4 ± 15.6 years) CT angiography of the aorta was performed using two- and three-zone scanning protocols with the voltage value on the X-ray tube (80 and 100kV) depending on the anthropometric measure namely body mass index (BMI). We compared dose length product parameters (DLP), effective dose (E), time and duration of scanning, as well as counting the amount of injected contrast agent (CM) between groups examined using a two-zone and three-zone protocols at an X-ray tube voltage of 80 and 100kV.
Results. Analysis of the data obtained showed that the DLP and E values were statistically significantly lower with the CT angiography of the aorta protocol, which consisted of three scanning zones (at 80kV p = 0.008; at 100kV p < 0.001). At the same time, there was no significant difference in the length of the study area in groups with the same voltage on the X-ray tube (p = 0.55), in the group with a three-zone protocol, the scanning time was significantly lower (p < 0.001) and amounted to 9.4 ± 0.5 sec/10.24 ± 0.9 sec (80/100kV), which made it possible to significantly reduce radiation exposure up to 40% and the amount of injected contrast agent by 20%.
Conclusions. The use of a three-zone CT-angiography of the aorta protocol with individual selection of voltage of the X-ray tube is justified and allows a significant reduction of radiation and iodine exposure compared to twozone scanning while maintaining the high images quality.

1. Congenital valvular aortic stenosis (VAS): Clinical recommendations of the Ministry of Health of the Russian Federation, 2016. (In Russian)

2. Iung B., Baron G., Butchart E.G. et al. A prospective survey of patients with valvular heart disease in Europe: The Euro Heart Survey on Valvular Heart Disease. Eur. Heart J. 2003; 24 (13): 1231–1243. http://doi.org/10.1016/s0195-668x(03)00201-x

3. Myung, K. Park Aortic stenosis. In: Myung K. Park, MD // Pediatric Cardiology for Practitiones, 2008: 248–257. ISBN-13: 978-0323014441; ISBN-10: 0323014445

4. Ivanov V.A., Evseev E.P., Aĭdamirov Ia.A. The outcomes of aortic valve replacement in patients with aortic stenosis and reduced left ventricular contractility. Kardiologiya i Serdechno-Sosudistaya Khirurgiya. 2016; 9 (5): 52–57. https://doi.org/10.17116/kardio20169552-57 (In Russian)

5. Clift P.F., Cervi E. A review of thoracic aortic aneurysm disease.Echo Res. Pract. 2019; 7 (1): R1–R10. https://doi.org/10.1530/ERP-19-0049

6. Leon M.B., Smith C.R., Mack M. et al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N. Engl. J. Med. 2010; 363: 1597–1607. https://doi.org/10.1056/NEJMoa1008232

7. Smith C.R., Leon M.B., Mack M.J. et al. Transcatheter versus surgical aortic- valve replacement in high-risk patients. N. Engl. J. Med. 2011; 364: 2187–2198. https://doi.org/10.1056/NEJMoa1103510

8. Blanke P., Weir-McCall J.R., Achenbach S. et al. Computed Tomography Imaging in the Context of Transcatheter Aortic Valve Implantation (TAVI)/Transcatheter Aortic Valve Replacement (TAVR): An Expert Con- sensus Document of the Society of Cardiovascular Computed Tomography. JACC Cardiovasc Imaging. 2019; 12: 1–24. https://doi.org/10.1016/j.jcmg.2018.12.003

9. Malakhova М.V., Prokhorova Е.А., Kulichkin А.S., Bril’ К.R., Van Е.Yu., Dzeranova А.N., Galyan Т.N., Khovrin V.V., Charchyan E.R. Diagnosis and Successful Surgical Treatment of Ascending Aorta Valved Conduit Rupture. Journal of Radiology and Nuclear Medicine. 2021; 102 (6): 383–389. https://doi.org/10.20862/0042-4676-2021-102-6-383-389 (In Russian)

10. Control of effective doses of irradiation of patients during medical X-ray examinations. MU 2.6.1.2944–11: 74–100 guidelines. (In Russian)

11. Solbak M.S., Henning M.K., England A. et al. Impact of iodine concentration and scan parameters on image quality, contrast enhancement and radiation dose in thoracic CT. Eur. Radiol. Exp. 2020; 4 (1): 57. https://doi.org/10.1186/s41747-020-00184-z

12. Ghekiere O., Salgado R., Buls N. et al. Image quality in coronary CT angiography: challenges and technical solutions. Br. J. Radiol. 2017; 90 (1072): 20160567. https://doi.org/10.1259/bjr.20160567

13. Kondratiev E.V., Karmazanovsky G.G. CT angiography: Optimized protocols of computed tomography angiography of the coronary arteries, the heart, the aorta, the vessels of the neck and brain. Moscow: Vidar, 2011. 88 p. (In Russian)

14. Kondratyev E.V., Karmazanovsky G.G., Shirokov V.S., Vishnevskaya A.V., Shvets E.V. Low Radiation Dose MDCT Angiography of the Aorta and Peripheral Arteries: Effect of Hybrid Iterative Reconstruction Technique on Image Quality. Medical Visualixation. 2013; 5: 11–22. (In Russian)

15. Shnayien S., Bressem K.K., Beetz N.L. et al. Radiation Dose Reduction in Preprocedural CT Imaging for TAVI/ TAVR Using a Novel 3-Phase Protocol: A Single Institution's Experience. Rofo. 2020; 192 (12): 1174–1182. http://doi.org/10.1055/a-1150-7646

16. Talei Franzesi C.R., Ippolito D., Riva L. et al. Diagnostic value of iterative reconstruction algorithm in low kV CT angiography (CTA) with low contrast medium volume for transcatheter aortic valve implantation (TAVI) planning: image quality and radiation dose exposure. Br. J. Radiol. 2018; 91 (1092): 20170802. http://doi.org/10.1259/bjr.20170802

17. Francone M., Budde R.P.J., Bremerich J. et al. CT and MR imaging prior to transcatheter aortic valve implantation: standardisation of scanning protocols, measurements and reporting-a consensus document by the European Society of Cardiovascular Radiology (ESCR). Eur. Radiol. 2019. http://doi.org/10.1007/s00330-019-06357-8

18. Meyer M., Haubenreisser H., Schoepf U.J. et al. Closing in on the K edge: coronary CT angiography at 100, 80, and 70 kV-initial comparison of a second- versus a thirdgeneration dual-source CT system. Radiology. 2014; 273 (2): 373–382. http://doi.org/10.1148/radiol.14140244