 Hello everyone, greeting to all myself, Dr. Rajat Sheikh, Department of Radio Diagnosis, Government Medical College and Hospital, Nagpur. I'm going to present my paper on topic coronary angiography with 256 slides, multi-detector city machine, its advantages, associated artifacts and their problem solving techniques. Let's go to the introduction. Historic heart disease is the leading cause of death in India as well as worldwide. The management basically depend upon physiological significance of coronary artery stenosis. The coronary artery disease is the progressive disease. If left untreated, there is mortality rate of 1% in chronic stable angina patients. The goals and investigation to assess the coronary artery is a still invasive coronary angiography, but it is invasive, expensive and time consuming. And it has a high risk of vascular access site complications. It also gives limited information on composition of atherosclerotic plaques and has a 0.15% mortality rate and 1.5% morbidity rate. As compared to death, city coronary angiography is a non-invasive and less time consuming technique. The scan can be done within 12 to 15 seconds. It reveals the complete arterial anatomy, also provides the information regarding the luminal narrowing and characterization of a calcific plaques. Thus currently, the multi- CT coronary angiography is considered as a promising alternative tool to invasive coronary angiography, especially in the low to intermediary coronary artery disease patients. The aims and objectives of this paper were to establish the role of city coronary angiography in evaluation of coronary arteries in ischemic heart disease patients to diagnose and characterize the calcific plaques, detect the various coronary artery anomalies and discuss various artifacts and their problem solving techniques. In the research plan, the study is conducted in tertiary care hospital in central India within the duration of 1.5 years, with the sample size of 75 patients. All the patients with chest pain and suspected ischemic heart disease were included in the study, along with the patients which were not adequately evaluated by invasive coronary angiography were included in the study. The patient with arterial fibrillation, unstable angina, hypersensitivity to contrast material, renal disease, heart failure, these patients were excluded from the study. The study was done with the help of Philips Brilliance I-256 slice MD CT machine. For the scan, the patient was kept NBM for 4 to 6 hours. The proper clinical history has been taken with correlation of KFT, ECG and 2D ECO reports. The optimal heart rate was obtained by giving the beta blocker, which the optimal heart rate was below 72 bits per minute. The patient kept supine with fit first position. The ECG lifts were fixed to the chest for ECG gating, and the patient was asked for proper breath hold during the scan. The CT coronary angiography has two parts. The first part is for obtaining coronary calcium score, which was done with the help of ECG gated non-contrast CT scan. And the second part is coronary angiography, which was done with the help of administration of IV contrasts at the rate of 5 to 7 ml per seconds. The CT coronary angiography can be performed prospectively and with the help of retrospective acquisition. Prospective, the prospective acquisition done in the patients with a normal heart rate and the retrospective acquisition was done in the patient with arrhythmia and higher heart rate patients. The retrospective acquisition has a side effect of more radiation exposure. The CT coronary angiography aids in a direct visualization of coronary artery anatomy and the plaques, which are further classified as non-calcified or soft plaques, partially calcified plaques, and completely calcified plaques. The soft lipid-rich plaques tends to have a lower attenuation than the soft fibrous plaques. The lower density plaques, which are less than 30 HU, has been described as a vulnerable plaques, and they have a higher risk of rupture. The other features of high risk plaques are soft calcification, presence of a positive remodeling, and napkin ring sign. The napkin ring sign refers to a plaque with a central hypo-attenuation area surrounded by the high attenuation rim. CT angiography images were analyzed for plaque and coronary tristinosis according to a cadrat system and graded accordingly from non-calcified to the completely occluded arteries. The 256 lice, multi-detector CT scan has an excellent spatial resolution and which can detect artery plaques with a high sensitivity of 94 percent, and the specificity of 83 percent as compared to the invasive coronary angiography. The accuracy is 95 percent for detection of coronary tristinosis, but the greatest strength of a CT coronary angiography lies in its excellent negative predictive value, which is about 99 percent. The common challenges were the common artifacts, which were cardiac motion artifacts due to high rate and arrhythmia of the patient, calcium blooming artifacts, and beam hardening artifacts. These were tackled by giving a oral or IV beta blocker to lower the heart rate and removing the data collected on ectopic bits with ECG editing software. Preferring a retrospective acquisition for arrhythmia patients and using iterative reconstruction algorithm to reduce the calcium blooming artifact, and the contrast injection was followed by saline bolus chaser. The observations of these studies are the most of the patients included in the study were males and were between 51 to 60 years. The most common symptom was typical angina and the important risk factor were hypertension, smoking, and followed by diabetes. On CT coronary angiography, the most patient had right coronary artery dominance on the coronary circulation. As the heart rate increased, the accessible coronary artery segment decreased. The most patient were with calcium score zero, the most atherosclerotic plaque were calcium flat plaque, and in the patient with typical angina with increased grade of stenosis. The left atherosclerotic artery was most commonly involved for calcific plaques, and as the calcium score increased, the grade of stenosis and clinically significant legions were increased. The most common artifact which was encountered is a motion artifact. In the summary, these are the observations of the study, and as a result, all the take home points are to the 256 slice MDCT angiography machine provides high accuracy for noninvasive detection and detection of suspected obstructive coronary artery disease. The procedure is safe and simple and can be completed within 12 to 15 seconds. The procedure is useful, reliable, and can be an alternative to diagnostic invasive coronary angiography, especially in the patients with low to intermediate risk for the localization of the coronary artery stenosis. It has a potential application of or to rule out the obstructive coronary artery disease, especially in patients who present with atypical chest pain into the emergency ward, and the patient with inconclusive stress. It can be a promising noninvasive tool to detect coronary artery stenosis and to assess the total plaque burden, the number of legions, the location of the legion, calcification status, and characterization, which shows superior prognostic impact, just more than the legion quantification. It also detects the anomalous origins of the coronary artery stenosis, which can be important information prior to the DSA angiography. And it also has the advantage of simultaneous visualization of cardiac anatomy and associate cardiac pathology before any cardiac intervention. Here are a few cases. The first case is showing a non-calcified plaque, which is causing around approximate 50% stenosis in proximal left anterior descending artery. In the second case, there are multiple calcified and eccentric plaques, which are involving the middle segment of left anterior descending artery and causing approximately 60% luminal narrowing, which were further confirmed on the DSA angiography. In the third case, there is anomalous origin of a left coronary artery from the right cusp and which is coursing between the aortic origin and pulmonary aorta, which is known as a malignant cusp. In the fourth image, there is anomalous origin of left circumflex artery from the right coronary cusp. In the 65-year field, this is the case of 65-year male, which has a history of post-MI and the stent in situ and which further presented with acute chest pain into the emergency department and followed with the CT coronary angiography showed a partial stenosis in just distal to the stent. The sixth case is of anomalous origin of a left coronary artery from the pulmonary artery also known as Al Capa syndrome. These are the few important references and I thank you, I thank CTBUS for giving me the opportunity and I also want to give my thanks to Dr. Jawa Rathursar, who is my guide and a co-author for this research. Thank you very much.