Acute Q fever pneumonia: high-resolution computed tomographic findings in six patients.

We analyzed high-resolution CT (HRCT) findings from six male patients (mean age, 22.6 years) with confirmed diagnoses of acute Q fever. Two chest radiologists analyzed the images and reached decisions by consensus. All patients presented fever, myalgia, prostation, headache, and dry cough. They also had common epidemiologic factors (recent travel for military service, where they had contact with sheep and capybara). Diagnoses were confirmed by the detection of C. burnetii DNA in clinical samples by polymerase chain reaction.The predominant HRCT findings were areas of consolidation (100%) and nodules (66.6%) with halos of ground-glass opacity, predominantly with segmental and peripheral distributions. Lesions affected all lobes, and predominated in the left upper and lower lobes. Involvement of more than one lobe was observed in four patients. No pleural effusion or lymph node enlargement was found.The predominant HRCT findings in patients with acute Q fever pneumonia were bilateral, peripheral areas of consolidation and nodules with irregular contours and halos of ground-glass opacity.Acute Q fever should be included in the differential diagnosis of lesions with the halo sign on HRCT.