ABSTRACT
Compared with ventilation-perfusion (VQ) scans, contrast-enhanced computed tomography (CT) has a high sensitivity and specificity for the diagnosis of pulmonary embolism (PE) (main through segmental arteries) 319–323 (Figures 9.1 and 10.30d). The advantages of CT are the speed and the wide availability in emergency departments. The CT scan allows direct visualization of the thrombus, and simultaneous assessment of the lung parenchyma and size of the cardiac chambers (e.g. right ventricular enlargement). On the other hand, CT does not provide an assessment of lung ventilation or perfusion (VQ scan) or right ventricular function (echocardiography, MRI). Pulmonary CT angiography can occasionally show other findings, including PA pseudoaneurysms (Figure 9.2). While most scans are performed with non-gated protocols, more recently ECG-synchronized protocols have been described. 323 Programs for computer-aided PE detection have been described. 324 Pulmonary embolism https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429186318/82d84425-00cf-4291-bf75-b4e9afc9ca9b/content/fig9_1.jpg"/> This figure shows images of a large left central pulmonary embolus. Pulmonary artery pseudoaneurysm https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429186318/82d84425-00cf-4291-bf75-b4e9afc9ca9b/content/fig9_2.jpg"/> This figure shows images of a patient with a suspected pseudoaneurysm following the placement of a pulmonary artery catheter. There are moderate bilateral pleural effusions with consolidation and atelectasis of the lower lobes. There is a pseudoaneurysm arising from the right middle lobe pulmonary artery, which measures approximately 4.0 × 3.3 cm.
