title: CT volumetric analysis of pleural effusions: a comparison with thoracentesis volumes.
abstract: OBJECTIVE
  The primary objective of this study was to compare computed tomography (CT) volumetric analysis of pleural effusions with thoracentesis volumes. The secondary objective of this study was to compare subjective grading of pleural effusion size with thoracentesis volumes.
  
  
  METHODS
  This was a retrospective study of 67 patients with free-flowing pleural effusions who underwent therapeutic thoracentesis. CT volumetric analysis was performed on all patients; the CT volumes were compared with the thoracentesis volumes. In addition, the subjective grading of pleural effusion size was compared with the thoracentesis volumes.
  
  
  RESULTS
  The average difference between CT volume and thoracentesis volume was 9.4 mL (1.3%) ± 290 mL (30%); these volumes were not statistically different (P = .79, paired two-tailed Student's t-test). The thoracentesis volume of a "small," "moderate," and "large" pleural effusion, as graded on chest CT, was found to be approximately 410 ± 260 cc, 770 ± 270 mL and 1370 ± 650 mL, respectively; the thoracentesis volume of a "small," "moderate," and "large" pleural effusion, as graded on chest radiograph, was found to be approximately 610 ± 320 mL, 1040 ± 460 mL, and 1530 ± 830 mL, respectively.
  
  
  CONCLUSIONS
  CT volumetric analysis is an accessible tool that can be used to accurately quantify the size of pleural effusions.
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia, 1215 Lee St, PO Box 800170, Charlottesville, VA 22908-0170. Electronic address: dsc5z@virginia.edu.
authors.forename: David
authors.initials: D
authors.lastname: Chiao
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia, 1215 Lee St, PO Box 800170, Charlottesville, VA 22908-0170.
authors.forename: Michael
authors.initials: M
authors.lastname: Hanley
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia, 1215 Lee St, PO Box 800170, Charlottesville, VA 22908-0170.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Olazagasti
mesh_terms: D015331:Cohort Studies; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D004322:Drainage / Q000379:methods; D006801:Humans; D010996:Pleural Effusion / Q000000981:diagnostic imaging*; D013902:Radiography, Thoracic / Q000379:methods; D012189:Retrospective Studies; D000069258:Thoracentesis / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods
keywords: Pleural effusion; computed tomography; quantitative; thoracentesis; volumetric analysis