title: Transthoracic sonography of diffuse parenchymal lung disease: the role of comet tail artifacts.
abstract: OBJECTIVE
  The value of transthoracic sonography in diffuse parenchymal lung disease is not established. This prospective study was conducted to analyze pleural and parenchymal alterations in patients with diffuse parenchymal lung disease by transthoracic sonography and to compare the results with the findings of a control group.
  
  
  METHODS
  Fifty-three patients with diffuse parenchymal lung disease and 35 control subjects underwent transthoracic sonography for assessment of (1) basal pleural effusion, (2) the presence and number of comet tail artifacts, (3) thickening, (4) an irregular, fragmented pleural line, and (5) subpleural alterations.
  
  
  RESULTS
  Basal pleural effusion was revealed in 37.7% of the patients with diffuse parenchymal lung disease (0% of the control subjects; P < .001), and 98.1% had multiple (>6 per scan) comet tail artifacts (14.3% of the control subjects; P < .001). Only a few artifacts (< or = 6 per scan; P < .001) were shown in 85.7% of the control subjects. All the control subjects had strongly localized comet tail artifacts and no thickened pleural line (84.9% of patients; P < .001). In 98.1 % of the patients, an irregular, fragmented pleural surface could be detected (82.8% of the control subjects; P < .05). Subpleural alterations were found in 37.7% of the patients and in 8.6% of the control subjects (P < .001).
  
  
  CONCLUSIONS
  Diffuse parenchymal lung disease should be considered if multiple comet tail artifacts distributed over the whole surface of the lung together with a thickened and irregular, fragmented pleural line are visible. Transthoracic sonography may reflect the distribution of pleural involvement and may show subpleural alterations.
authors.affiliation: Pneumology and Allergology, Department IV Medical University Clinics, Friedrich-Schiller-University, Jena, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Reissig
authors.forename: Claus
authors.initials: C
authors.lastname: Kroegel
mesh_terms: D016477:Artifacts; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008171:Lung Diseases / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000000981:diagnostic imaging; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography