Masks of Pulmonary Thromboembolism on Chest Radiographs

Aim. Assessment of detectability of pulmonary thromboembolism on radiographs. Identification of masks of pulmonary thromboembolism manifestations mimicking other diseases on radiographs. Materials and Methods. The retrospective analysis included 23 patients with pulmonary embolism proven by computed tomography, who were treated at the SBHI City Hospital No. 26. All patients underwent digital chest radiography in two projections on admission using a Samsung XGEO GC80 digital X-ray machine. Computed tomography was performed on a 128-slice General Electric Revolution EVO tomograph using intravenous bolus contrast with Omnipaque at a concentration of 300 mg iodine/ml. The findings of radiologists were compared with the data of computed tomography; detectability of pulmonary embolism on radiographs, correlation between the embolism massiveness and its manifestations on radiographs were evaluated. Results. Among the 23 digital radiographs interpreted, pulmonary thromboembolism was suspected in 1 case (detection rate of 4 %). In 8 cases (35 %) no abnormalities were found on radiographs. In three patients (13 %) findings were interpreted as manifestations of peripheral lung cancer, that turned out to be areas of pulmonary infarction on CT. The detection rate of indirect signs of pulmonary thromboembolism (discoid atelectasis, small hydrothorax, infarctions, pulmonary hypertension) was at least twice as high in the CT examination. No correlation between the massiveness of thromboembolism and its manifestations on radiographs has been revealed. The most frequent manifestations of pulmonary thromboembolism on radiographs were discoid atelectasis (35 %), lung infarction (35 %), small hydrothorax (26 %) and high position of the diaphragm on the affected side (22 %). Rare sign was dilatation of the pulmonary artery trunk (9 %). Conclusion. The detectability of pulmonary thromboembolism on digital radiographs is extremely low. Most often this diagnosis is hidden under the mask of a normal X-ray, tumour lesions or manifestations of cardiac insufficiency (hydrothorax). The lack of direct correlation between thromboembolism massiveness and lesions seen on radiographs requires the radiologist to be more attentive to clinical symptoms (sudden dyspnoea, chest pain, dry cough, etc.) when interpreting radiographs.