title: Pulmonary Legionellosis in Oncologic Patients: Findings on Chest CT.
abstract: OBJECTIVE
  The purpose of this study was to report the computed tomography (CT) findings of non-pneumophila Legionella pneumonia and to compare these CT findings to those caused by Legionella pneumophila in oncologic patients.
  
  
  METHODS
  Chest CT scans of 34 oncologic patients with culture-proven Legionella infection (16 L. pneumophila and 18 non-pneumophila Legionella) were retrospectively reviewed. Radiologic checkpoints included consolidation, ground-glass opacities, cavitation, nodules, tree-in-bud opacities, septal thickening, pleural effusions, and adenopathy, as well as the halo, reversed halo, and bulging fissure signs.
  
  
  RESULTS
  The most common imaging feature of Legionella pneumonia was consolidation, seen in 94% of patients. Ground-glass opacities were the next most common abnormality. The halo sign was present in 26% of patients, in both immunocompetent and immunosuppressed hosts. Most features occurred with similar frequency between L. pneumophila and non-pneumophila Legionella.
  
  
  CONCLUSIONS
  Findings in L. pneumophila pneumonia and non-pneumophila Legionella pneumonia are similar but nonspecific. Airspace consolidation is almost always present; the halo sign is not uncommon.
authors.affiliation: From the *The University of Texas MD Anderson Cancer Center, Houston, TX; and †Department of Diagnostic Imaging, The Chaim Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Girish S
authors.initials: GS
authors.lastname: Shroff
authors.forename: Edith M
authors.initials: EM
authors.lastname: Marom
authors.forename: Carol C
authors.initials: CC
authors.lastname: Wu
authors.forename: Myrna C B
authors.initials: MC
authors.lastname: Godoy
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Andrea
authors.initials: A
authors.lastname: Ihegword
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Han
authors.forename: Mylene T
authors.initials: MT
authors.lastname: Truong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007875:Legionella / Q000302:isolation & purification; D007876:Legionellosis / Q000000981:diagnostic imaging* / Q000382:microbiology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000000981:diagnostic imaging* / Q000382:microbiology; D013902:Radiography, Thoracic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*