Introduction and Objectives The role of diagnostic imaging in pulmonary embolism (PE) is being increasingly undertaken by CT pulmonary angiography (CTPA) and there has been an explosion of usage in our trust in the last two years, which reflects a growing trend in clinical practice in the United Kingdom (UK). There has been an abundance of literature on how best to utilise CTPA with particular attention to optimisation of pulmonary artery opacification to aid diagnosis. An additional benefit of CTPA over other modalities for the diagnosis of PE that may be less widely appreciated is CTPAs ability to provide simultaneous information on other pathologies affecting the thorax and alternative diagnoses requiring further clinical management.

Methods To this cause a sample of 400 CTPAs were retrospectively reviewed in a 1001 bed acute teaching hospital in the UK, to identify the common types of additional pathology demonstrated. The presence of PE and any additional pathology, with special attention to “incidental” pathology, or pathology that was unsuspected but which was significant enough to change the patient's management was recorded, in order to identify the common incidental pathologies that we should be actively hunting for when reviewing a CTPA.

Results PE was demonstrated in 94 studies (22.6%; 95% CI 18.7% to 26.9%). Additional pathology was seen in 373 studies (89.7%; 95% CI 86.3% to 92.4%), of which 58 (15.6%; 95% CI 12.0% to 19.6%) were reported as incidental. These included coronary calcification, degenerative spine, aortic disease, valve disease, liver cyst, retro-sternal goitre, anatomical variant, gallstone/gallbladder disease, scapula lesion, rib fracture/deformity. Forty-three cases (10.3%) went on to require further investigation or follow-up. One hundred and ten caes (26.4%) showed no PE but an alternative diagnosis i.e. effusion/consolidation.

Conclusion The prevalence of PE in our sample was 22%. Secondary findings were found in 89.7% of scans, with completely incidental findings reported in 15.6% and an alternative diagnosis when there was no PE in 26.4%. This emphasises the usefulness of CTPA in supplying further diagnostic data in patients with suspected PE.