Purpose: The objective of this study was to investigate the factors that may influence image quality on multidetector computed tomography (MDCT) coronary angiography (CA). Materials and Methods: Two hundred twenty-four consecutive patients (161 men and 63 women; mean age, 52 years; age range, 34-76 years) evaluated with MDCT CA were included in the study. The evaluation of the quality of the patients' images was mainly based on the contrast material phase (early phase, optimal phase, or late phase) and the level of stepladder artifact (none, acceptable, or unacceptable). In addition, factors such as patient selection, patient preparation, scanning, processing, and steps of analysis, which may be affecting the quality of a final image, were examined independently. Results: Patients who could not achieve sufficient breath-holding despite multiple breath exercises, those with a calcium score of 500 or higher, those with a heart rate greater than 90 bpm after metoprolol administration (because of shortening of the diastolic phase in the most still period), and those whose scanning was not completed were excluded from the study. The results for the remaining 224 patients were evaluated. Based on the contrast phase, there were 66 (29.5%) patients in the first group (early), 93 (41.5%) in the second group (optimal), and 65 (29%) in the third group (late). Among the 224 patients, the images of 152 (67.9%) had no stepladder artifact, those of 67 (29.9%) were of acceptable image quality, and those of 5 (2.2%) were of unacceptable image quality. Conclusion: It is important to obtain high-quality images to achieve correct interpretation with coronary artery CT angiography. This study aimed to describe a technique performed on 224 patients based on an array of factors ranging from patient selection to postprocessing. The results show that patient selection, cooperation with the patient, and breath-holding exercises play a very important role in obtaining the best images. In addition, a proper scanning technique (e.g., placement of electrocardiographic electrodes and contrast material phase) and postprocessing (e.g., reconstruction interval) may also contribute to obtaining high-quality images. (c) 2007 Elsevier Inc. All rights reserved.