Pulmonary embolism (PE) can be easily diagnosed with computed tomography pulmonary angiography (CTPA). However, the diagnosis of PE is difficult when contrast material cannot be used.

The aim of this study is to investigate whether an increase in Pulmonary Artery- Diameter and an increase in PA-Diameter / Ascending Aortic-Diameter ratio can be used in the diagnosis of PE.

CTPA of patients diagnosed with PE (88 patients) and control group (89 patients) were examined retrospectively. Aortic (Ao) and pulmonary artery (PA) diameters were measured radiologically. PA-Diameter/Ao-Diameter ratio were proportioned.

Mean D-Dimer levels were found to be higher in the PE group (7.31±3.528 mcg/L) than in the control group (1.52±1.042 mcg/L), (p<0.001). PE diagnosis of right main PA, right segmental PA and right subsegmental PA was observed more than left. In PE group the mean Ao-Diameter (35,14±4,55 mm) was larger than in control group (34,97±5,28 mm), (p=0.828). In PE group the mean main PA-Diameter (30,45±4,77 mm) was larger than in control group (28,35±3,81 mm), (p=0.001). Also in PE group the mean main PA-Dimeter/Ao-Diameter ratio (0,87±0,15) were higher than in control group (0,82±0,13), (p=0.016).

The increase in PA-Diameter and PA-Diameter/Ao-Diameter ratio in non-contrast CT can be used in the diagnosis of PE in patients with suspected PE in whom contrast cannot be given in the ED.