How Can an Updated 320 Multi Detector Computed Tomography Low Dose Protocol Help in Assessment of Coronary Heart Disease

Background Coronary artery disease (CAD) is the single most common cause of death in the developed world, responsible for about I in every 5 deaths. The morbidity, mortality, and socioeconomic importance of this disease make timely accurate diagnosis and cost-effective management of CAD of the utmost importance. The recent years showed an overall increase in the use of CT for imaging of the heart and coronary arteries, coronary CT angiography is a rapidly growing technique that offers distinct advantages over traditional imaging techniques. However, because of rapid growth of this technique, radiation dose safety has been placed under the spotlight. Integration of dosesaving techniques will go a long way in maintaining diagnostic image quality and improving patient safety. Objectives The purpose of our study is the assessment of coronary artery disease by 320 MDCT and its capabilities of maintaining the quality of images and dose reduction improving patient safety. Patients and Methods This study was performed at New Cairo Police Hospital (Radiology department) and at Center in East Cairo, From October 2018 to October 2019, a total of 39 patients who had referred for CTCA for suspicion of coronary artery disease enrolled in our prospective study. Results In this study we used MDCT 64 with retrospective ECG-gating in 25.6% of patients (10 patients) and MDCT 320 with Retrospective ECG-gating was used in 25.6% (10 patients) and with Prospective ECG-gating in 48.8% (19 patients).we compared the radiation dose between prospective ECG-gating and retrospective ECG-gating acquisition techniques among all study population by the effective dose (ED) which is calculated from the DLP of the coronary scan. The effective radiation dose (ED) median was significantly lower in the prospective ECG-gating technique (7 msv) in comparison to retrospective ECG-gating technique (23 msv). We also compared the difference in radiation dose between MDCT 320 and 64 using retrospective ECG gating acquisition technique, the median (ED) was significantly lower in the 320 MI)CT technique (20 msv) in comparison to 64 MDCT (26 msv). The last comparison was the difference Of radiation dose between patients who underwent through MDCT 320 using two different techniques (prospective and retrospective), the median effective dose was lower in the prospective ECG-gating technique (7 msv) in comparison to retrospective ECG-gating technique (20 msv) this difference is also of high statistical significant value. Conclusion Prospective ECG-Gated CT coronary angiography protocol impressively reduces effective radiation doses in comparison to retrospective ECG-gated technique on 320 MDCT and is still sensitive for diagnosing significant coronary stenosis for patients with suspected CAD. Retrospective Coronary CT angiography can be performed with 320-MDCT with less radiation doses compared to 64-MDCT.