title: Comparison of criteria to truncate gastric emptying tests.
abstract: OBJECTIVE
  Standardized scintigraphic gastric emptying (GE) protocols to detect gastroparesis (GP) require collecting data for 4 h. This investigation was undertaken to compare seven methods to reduce the duration of the test.
  
  
  METHODS
  This was a retrospective study of GE data collected using a standardized protocol at 0, 1, 2, 3, and 4 h for 602 patients being evaluated for GP. The reference standard was GP defined conventionally as percentage of gastric retention (GR) at 4 h (p4) of greater than 10%. For data up to 2 h the results were derived as follows: (a) confirming as being positive for GP if GR at 2 h was greater than 65%, negative for GP if GR at 2 h was less than 45%, and indeterminate otherwise; (b) by linear extrapolation; and (c) by monoexponential extrapolation. For data beyond 2 h, further evaluations were made and results were derived as follows: (a) confirming as being positive for GP if GR at 2.5 h was greater than 40%; (b) ascertainment of GR at 3 h; (c) by biphasic fit; and (d) by observation of maximum GR for normal patients at time points earlier than 4 h.
  
  
  RESULTS
  Thirty percent of all patients had GP. Eighty percent were determinate by Method 1; for these patients sensitivity to detect GP was similar (P=0.11) for Methods 1-3 (69-79%). For data beyond 2 h, sensitivity of the seven methods ranged from 64 to 92%, and the sensitivity of every method was significantly lower than that of the reference standard (P<0.001).
  
  
  CONCLUSIONS
  Considering that sensitivity to detect GP was significantly reduced for data collection limited to 3 h or less, it is not advisable to truncate GE studies earlier than 4 h.
authors.affiliation: Department of Radiology, Division of Nuclear Medicine and Molecular Imaging, North Shore - Long Island Jewish Health System, Manhasset and New Hyde Park, New York, USA. knichols@lij.edu
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Nichols
authors.forename: Gene G
authors.initials: GG
authors.lastname: Tronco
authors.forename: Maria B
authors.initials: MB
authors.lastname: Tomas
authors.forename: Zaman
authors.initials: Z
authors.lastname: Javaheri
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Palestro
mesh_terms: D005260:Female; D005746:Gastric Emptying; D018589:Gastroparesis / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors