The aim of this study was to compare oesophageal abnormalities observed in high-resolution CT with radionuclide transit in patients with systemic sclerosis. 76 patients with systemic sclerosis were evaluated by high-resolution CT and oesophageal transit scintigraphy. Residual activity > or =20% (in relation to peak activity) at 15 s after the beginning of the swallow of the labelled liquid (in supine position) was considered indicative of oesophageal dysfunction. Supra-aortic and infra-aortic oesophageal coronal diameters were measured in high-resolution CT. Oesophageal dilatation was deemed present when the diameters exceeded 10 mm. 19 patients (25%) had supra-aortic oesophageal dilatation and 48 patients (63.1%) had infra-aortic dilatation. The prevalence of radionuclide transit delay was 77.6%. All patients (19/19) with supra-aortic dilatation had oesophageal dysfunction, compared with 70.2% (40/57) of the patients with no supra-aortic dilatation (p = 0.004). Oesophageal dysfunction was present in 97.9% (47/48) of patients with infra-aortic dilatation, compared with 42.9% (12/28) in patients without it (p < 0.001). Receiver operating characteristic (ROC) curves have demonstrated that the supra-aortic and infra-aortic diameters had good discriminatory capacity for oesophageal dysfunction in systemic sclerosis (area under the curve, 95% confidence interval: 0.80, 0.70-0.89 and 0.92, 0.86-0.98, respectively). There is a clinically significant association between oesophageal dysmotility and high-resolution CT findings of oesophageal coronal dilatation. The evaluation of infra-aortic oesophageal coronal diameter can provide additional useful information about the functional and anatomic conditions of the oesophagus in systemic sclerosis.