The metallic component of coronary stents makes it difficult to study their lumen by angio scanner. The object of this preliminary study was to appreciate the factors influencing the diagnosis of restenosis after stenting the left main coronary artery by 16-slice spiral angio CT. This Monocentric study included 27 patients who underwent 16-slice spiral angio CT six months after stenting of the left main coronary artery. It was possible to assess the stent lumen in 21 patients (78%) and no cases of > 50% restenosis were observed. In 4 patients, hypodense zones adjacent to the stent links were observed suggesting moderate intimal hyperplasia. The tests for ischaemia were normal in 3 of these patients. Coronary angiography and endocoronary ultrasound excluded significant restenosis in the fourth patient. In univariable analysis, the facors associated with good or excellent angioscanner quality (45% of patients) were Ostial stenosis (p = 0.03), no or minimal calcification on initial coronary angiography (p = 0.0S), stent diameters > 3.5mm (p = 0.03), heart rates < 60/min (p = 0.04), absence of extrasystoles (p = 0.05) during acquisition. In multivariable analysis, the only significant factors were absent or minimal calcification and stent diameters > 3.5mm (p = 0.02). The multidetector scanner seems a very promising method of investigating patients who have undergone stenting of the left main coronary artery but this study shows that certain clinical and angiographic parameters are limiting factors of surveillance with a 16-slice angioscanner.