title: Early detection of pneumonia in febrile neutropenic patients: use of thin-section CT.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the usefulness of thin-section CT for early detection of pneumonia in neutropenic patients with an unknown site of infection and normal or nonspecific findings on chest radiographs.
  
  
  METHODS
  Eighty-seven patients with febrile neutropenia that persisted for more than 2 days despite empiric antibiotic treatment underwent 146 prospective examinations. If findings on chest radiographs were normal (n = 126) or nonspecific (n = 20), thin-section CT (1-mm collimation, 10-mm increment) was done. If thin-section CT scans showed opacities, bronchoalveolar lavage was recommended.
  
  
  RESULTS
  Findings on chest radiographs were nonspecific for pneumonia in 20 (14%) of 146 cases, and CT findings in those cases were suggestive of pneumonia. Microorganisms were detected in 11 of those 20 cases. Seven of the 11 cases were not optimally treated before CT diagnosis, the other four were sufficiently treated. Findings on chest radiographs and thin-section CT scans were normal in 56 (38%) of 146 cases. In 70 (48%) of 146 cases, findings on chest radiographs were normal, whereas findings on thin-section CT scans were suggestive of pneumonia. Microorganisms were detected in 30 of the 70 cases. Nineteen of 30 cases were not optimally treated before CT, whereas the other 11 cases were sufficiently treated before CT. In 22 (31%) of these 70 cases, an opacity was observed on the chest radiograph during the 7 days after the CT study. Only three (5%) of 56 pneumonias occurred during the first 7 days after thin-section CT studies with normal findings (p < .005). Additional risk factors for pneumonia occurring later that were detectable on chest radiographs were poorly defined nodules (p < .05), consolidation (p < .05), and younger age (p < .05).
  
  
  CONCLUSIONS
  Thin-section CT scans show findings suggestive of pneumonia about 5 days earlier than chest radiographs show suggestive findings. When thin-section CT scans show findings suggestive of pneumonia, the probability of pneumonia being detected on chest radiographs during the 7-day follow-up is 31%, whereas the probability is only 5% when the findings on the prior thin-section CT scan were normal (p < .005). All neutropenic patients with fever of unknown origin and normal findings on chest radiographs should be examined with thin-section CT.
authors.affiliation: Department of Radiology, Johannes Gutenberg University, Mainz, Germany.
authors.forename: C P
authors.initials: CP
authors.lastname: Heussel
authors.forename: H U
authors.initials: HU
authors.lastname: Kauczor
authors.forename: G
authors.initials: G
authors.lastname: Heussel
authors.forename: B
authors.initials: B
authors.lastname: Fischer
authors.forename: P
authors.initials: P
authors.lastname: Mildenberger
authors.forename: M
authors.initials: M
authors.lastname: Thelen
mesh_terms: D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use; D001992:Bronchoalveolar Lavage Fluid; D005069:Evaluation Studies as Topic; D005260:Female; D005335:Fever of Unknown Origin / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy; D009503:Neutropenia / Q000139:chemically induced* / Q000150:complications; D011014:Pneumonia / Q000000981:diagnostic imaging* / Q000209:etiology / Q000382:microbiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000970:Antineoplastic Agents