Differential diagnosis of acute and chronic pulmonary thromboembolism according to MSCT data

Introduction. One of the important problems of medical imaging is the differential diagnosis of patients with acute and chronic pulmonary embolism. The widely used minimally invasive technique of multispiral computed tomography with intravenous bolus contrast enhancement can serve to solve this problem, in particular, to assess the state of the parenchyma and vascular structures of the lungs.

The purpose. To assess the state of bronchial arteries and parenchymal changes in the lungs in pulmonary thromboembolism based on the results of multispiral computed tomography and their role in the more precise diagnosis of this disease.
Materials and methods. An analysis of CT-angiopulmonography of 600 patients with suspected PE was performed. 87 patients with confirmed pulmonary thromboembolism were selected and divided into groups according to the final diagnosis: group 1 — acute pulmonary embolism, group 2 — chronic pulmonary embolism. CT data were analyzed for the presence of pathologically changed bronchial arteries, as well as lung's parenchymal changes (including mosaic perfusion, fibrotic changes, bronchial dilatation with or without wall thickening).
Results. Bronchial arteries were assessed in patients with acute and chronic pulmonary embolism and the diagnostic value of the detected changes was determined. Acute pulmonary embolism does not lead to such dilatation of the bronchial arteries as chronic pulmonary embolism. In diagnostically unclear cases, secondary parenchymal signs visible on CT (mosaic perfusion and dilated bronchi without wall thickening) can be useful in the differential diagnosis of acute and chronic pulmonary embolism.

Conclusions. Most patients with chronic pulmonary embolism demonstrated dilated bronchial arteries, in contrast to patients with acute pulmonary embolism. Lung's parenchymal changes (a mosaic perfusion pattern and bronchial dilation without wall thickening) were more common in patients with chronic pulmonary embolism. These CT-signs can help differentiate acute from chronic pulmonary embolism in unclear clinical situations.

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