Computed tomography pulmonary angiography: a sample of experience at a District General Hospital

Pulmonary embolism (PE) has a significant associated morbidity and mortality. The role of diagnostic imaging in PE is being increasingly undertaken by computed tomography pulmonary angiography (CTPA). An advantage of CTPA is its ability to simultaneously provide information on the lung parenchyma, mediastinum, pleural spaces, and chest wall. A sample of CTPAs was therefore reviewed to identify the types of additional pathology demonstrated.

One hundred and ninety-eight CTPA examinations were retrospectively reviewed. A record was made of the presence of PE and any additional pathology, with particular interest given to "incidental" pathology, or pathology that was unsuspected but which was significant enough to change the patient's management. A note was also made as to the adequacy of the study. D-Dimer values were recorded when available.

PE was demonstrated in 56 studies (28.3%). Additional pathology was seen in 112 studies (56.6%), of which 17 were categorised as incidental. These included multiple pulmonary nodules, solitary lung lesions, destructive bony lesions, pancreatitis, a solid renal mass, mesothelioma, reactivated pulmonary tuberculosis, recurrent bronchial carcinoma, pulmonary fibrosis, an SVC filling defect, and a compression fracture of T10.

The prevalence of PE in our sample was 28.3%, compared with a reported prevalence, mainly by pulmonary angiography, of between 19% and 79%. Secondary findings were found in 56.6% of scans, with completely incidental findings demonstrated in 17 patients (9%). This emphasizes the usefulness of CTPA in providing additional diagnostic information and alternative diagnoses in patients with suspected PE.