PURPOSE: To prospectively determine the utility of chest pain protocol by 16-Slic Multidetector CT (MDCT) in the examination of patients who had atypical chest pain in the outpatient clinic METHOD AND MATERIALS: Ninety six patients clinically having atypical chest pain were consecutively examined with 16 slice MDCT (sensation 16, Siemens), including both CT coronary angiography (CA) and noncontrasted chest CT scan. When significant stenoses (> or =50% lumen diameter reduction) were detected on CT CA, invasive CA was performed as the standard of reference. In all patients, at least 6 months later, chart review or telephone contact with the referring clinician was used to evaluate the contribution of MDCT with chest pain protocol to the final clinical diagnosis RESULTS: Five patients (5%) have significant stenoses on CT CA, whereas 1 patient (1%) has a significant stenosis and 4 patients have insignificant stenoses or no stenosis on conventional CT. In 32 (34%) of the 95 patients without significant stenosis on CT CA or conventional CA, MDCT provided additional information that suggested or confirmed the alternate clinical diagnosis: pneumonia (n = 2), emphysema (n = 7), Hypertrophic cardiomyopathy(n=1). atelectasis (n = 2), bronchiectasis (n = 2), multiple mediastinal LN enlargement (n = 1), pleural disease (n = 1), pleural effusion(n = 2 ) active pulmonary tuberculosis (n = 1), inactive pulmonary tuberculosis (n = 7), benign pulmonary nodule (n=5). Coronary artery disease were excluded in the remaining 63 (66%) patients with normal on MDCT with a negative treadmill test or by means of telephone contact CONCLUSIONS: In patients with atypical chest pain in outpatient clinic, the minority of patients had significant stenoses of coronary artery. MDCT with chest pain protocol could help to detect a significant stenosis of coronary artery, it also provides important ancillary information for the final diagnosis.