Beyond the Pulmonary Arteries: Alternative Diagnoses in Children With MDCT Pulmonary Angiography Negative for Pulmonary Embolism

Abstract

A potential advantage of pulmonary CT angiography (CTA) is its ability to show alternative diagnoses in patients without evidence of pulmonary embolism (PE), but the frequency and spectrum of alternative diagnoses have yet to be determined in the pediatric population. Our purpose was to determine the frequency and types of alternative diagnoses identified in children with clinically suspected but excluded PE. We used our hospital information system to identify all consecutive pediatric patients (< 18 years old) with clinically suspected PE who underwent pulmonary CTA from July 2004 to March 2008. Two experienced pediatric radiologists reviewed by consensus a series of 96 consecutive diagnostic-quality pulmonary CTA studies without evidence of PE from 89 patients. Each study was systematically reviewed by consensus for a possible alternative diagnosis in the lungs, mediastinum, central airways, cardiovascular system, pleura, and skeleton. The study population consisted of 89 children (28 boys and 61 girls; mean age 13.4 +/- 4.7 years; range, 2 months-18 years; 34 inpatients, 62 outpatients) who underwent a total of 96 pulmonary CTA studies without evidence of PE. Thirty-nine (41%) of 96 pulmonary CTA studies were normal. Alternative diagnoses were identified for each of the remaining 57 (59%) studies, including: pneumonia (n = 22), atelectasis (n = 22), malignancy (n = 3), congenital heart disease (n = 2), pulmonary hypertension (n = 2), pericardial effusion (n = 2), pulmonary nodules (n = 1), rib fractures (n = 1), right atrial thrombus (n = 1), and fat embolism (n = 1). Seventeen patients showed pleural effusions that were associated with coexisting pneumonia (n = 8), atelectasis (n = 8), or rib fractures (n = 1). Among children with clinically suspected but excluded PE, pulmonary CTA frequently shows positive findings. Although pneumonia and atelectasis are most common, a variety of other alternative diagnoses may be detected throughout the thorax.