title: Optimal Time Points for Scintigraphic Imaging of Pleuroperitoneal Shunts.
abstract: OBJECTIVE
  Nuclear imaging can confirm pleuroperitoneal shunt as the cause of pleural effusion. No society guidelines exist for scintigraphic pleuroperitoneal shunt detection. Our institutional protocol was evaluated to determine optimal imaging time points for shunt detection.
  
  
  METHODS
  Pleuroperitoneal shunt studies over 4 years were blindly reviewed by 2 nuclear radiologists. Data from blinded review included presence or absence of pleuroperitoneal shunt, laterality of shunt and time points for shunt detection.
  
  
  RESULTS
  Chart review yielded 30 studies. Three cases were excluded because of improper injection. Imaging was positive for pleuroperitoneal shunt in 81% (22/27) of cases. In positive cases, activity was identified in the right hemithorax in 82% (18/22), left hemithorax in 9% (2/22), and bilaterally in 9% (2/22). One-hour imaging demonstrated 91% (20/22) of positive cases. The remaining 2 positive cases were negative at 1 hour but positive after 4 hours. No study was negative at 1 and 4 hours and positive at 24 hours. All negative cases (5/27) were confirmed on 24-hour imaging.
  
  
  CONCLUSIONS
  The majority of positive pleuroperitoneal shunt examinations will demonstrate activity in the right hemithorax on 1-hour imaging. Although no case was negative at 1 and 4 hours and positive at 24 hours, imaging at 24 hours may still be necessary to confirm absence of shunt. Therefore, optimal imaging time points consist of early 1-hour and delayed 24-hour images if the 1-hour time point was negative. The 4-hour time point may be considered optional, thereby potentially optimizing patient safety and resource utilization.
authors.affiliation: From the *Department of Medical Imaging, Banner University Medical Center Tucson, University of Arizona College of Medicine, Tucson, AZ; †Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA; and ‡Departments of Medical Imaging, Medicine and Biomedical Engineering, University of Arizona College of Medicine, Tucson, AZ.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Covington
authors.forename: Gagandeep
authors.initials: G
authors.lastname: Choudhary
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Avery
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Krupinski
authors.forename: Phillip H
authors.initials: PH
authors.lastname: Kuo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D035422:Pleural Cavity / Q000000981:diagnostic imaging*; D010996:Pleural Effusion / Q000150:complications / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging / Q000379:methods*; D012189:Retrospective Studies; D013909:Thorax / Q000000981:diagnostic imaging; D013997:Time Factors; D055815:Young Adult