CT Manifestations of Pulmonary Infarction Secondary to Acute Pulmonary Embolism

Objective: To investigate the CT findings of pulmonary infarction (PI) secondary to acute pulmonary embolism (APE). Method: The clinical and CT data of 41 patients with PI secondary to APE were analyzed retrospectively. The number, location, shape, margin of PI, pleural effusion and dynamic changes were summarized. Results: CT features of PI: (1) Number and location: Among the total 79 PI lesions, 18 patients had single lesion and 23 patients had multiple lesions. All lesions were located under the pleura and connected to the pleura with a broad base, 46.8% (37/79) were located in the lower lobe of the right lung, 36.7% (29/79) in the lower lobe of the left lung, 3.8% (3/79) in the upper lobe, 6.3% (5/79) in the middle lobe of the right lung, and 6.3% (5/79) in the lingual segment of the upper lobe of the left lung. (2) Shape: 45.6% (36/79) of the lesions showed Reversed Halo Sign (RHS), 36.7% (29/79) displayed consolidation of oval, wedge or hump, 17.7% (14/79) revealed ground glass opacity. (3) Bronchovascular bundles in PI: Bronchovascular bundles were found in 79.7% (63/79) of PI. In 21.3% (16/79) of the cases, there was no bronchovascular bundle in the lesion because of its small size; (4) After enhancement, there was no enhancement shown in the 79 PI lesions. (5) All 79 lesions changed into patchy or linear during the end of the treatment period. (6) Pleural effusion: 63.4% (26/41) of patients had pleural effusion, among whom 42.3% (11/26) had bilateral pleural effusion, and 57.7% (15/26) had unilateral pleural effusion. Conclusion: The imaging manifeatations of PE secondary to API hole certain characteristics. For single or multiple lesions under the pleura, with RHS, consolidation of wedge or hump, bronchovascular bundles, APE secondary to API should be considered. In addition, pleural effusion is helpful for diagnosis.