Impact of chest CT on the clinical management of immunocompetent emergency department patients with chest radiographic findings of pneumonia

The purpose of this study is to assess the impact on clinical decision making of chest computed tomography (CT) in immunocompetent emergency department (ED) patients with chest radiographic (CXR) findings of pneumonia. We retrospectively identified 1,373 patients from our ED who underwent chest CT between 7/05 and 6/06. Report of CXR within 24 h before CT were reviewed to identify patients with findings of pneumonia. The following were the exclusion criteria: recommendation of CT on CXR report and immunocompromised status on chart review. Fifty-one patients met the inclusion criteria: 26 women and 25 men, with a mean age of 60 (range 29-103) years. Age- and sex-matched controls from the ED with CXR findings of pneumonia who did not undergo CT were identified. Charts were reviewed for clinical presentation, management, and follow-up. Patient and control groups were compared using Fisher exact and paired Student's t tests. The patients were sicker than the controls with more signs and symptoms including auscultation abnormalities, 64 (33 of 51) vs 47% (24 of 51), abnormal sputum 32 (16 of 51) vs 0%, hypoxemia 22 (11 of 51) vs 2% (1 of 51), weight loss, 20 (10 of 51) vs 4% (2 of 51), and night sweats, 16 (8 of 51) vs 2% (1 of 51; p<0.05 each). Clinical management, (based on CT findings in 31% [16 of 51]), was more extensive for patients than controls: antibiotics initiated 82 (41 of 51) vs 47% (24 of 51), antibiotics changed 29 (15 of 31) vs 0%, procedures performed 24 (12 of 51) vs 0%, and mean length of stay was 8 days vs less than 1 (p<0.05, each). Sixteen percent (8 of 51) of the patients had alternative/additional diagnosis based on CT: pulmonary embolism, lung cancer, hypersensitivity pneumonitis, multiple myeloma, renal cell carcinoma, small bowel obstruction, lung nodule, and endobronchial mass (n=1, each). Eight percent (4 of 51) of the patients and no controls were diagnosed with tuberculosis (p=0.06). Immunocompetent ED patients with CXR findings of pneumonia who underwent chest CT were sicker than those who were not imaged with CT. Chest CT was often useful in guiding therapy or providing an alternative diagnosis. © 2007 Am Soc Emergency Radiol.