We report the case of an asymptomatic 67-year-old man with positive ECG stress testing in whom low-dose multidetector computed tomography (MDCT) demonstrated a large aneurysm associated with critical stenoses of the mid left anterior descending coronary artery. A detailed anatomical depiction of this complex coronary lesion was obtained with MDCT despite very low radiation exposure (1.7 mSv). Invasive coronary angiography confirmed the MDCT findings and surgical treatment was successfully performed.