title: The lag phase of gastric emptying: clinical, mathematical and in vitro studies.
abstract: The lag phase of gastric emptying reflects, in large measure, the clinically important milling function of the stomach, but there is little agreement on the best way to acquire, analyze and characterize lag phase data of gastric emptying studies.
  
  
  METHODS
  Twenty normal volunteers were fed a standard 99mTc-sulfur colloid scrambled egg and toast breakfast and imaging data were acquired at 15-min intervals in both anterior and posterior projections with the subject seated.
  
  
  RESULTS
  In a significant percentage of the subjects, the stomach count rate rose above the initial count rate, even with geometric mean correction. We attributed the count rate rise to meal self-absorption and conducted mathematical and in vitro experiments, the results of which supported this thesis. Attempts at modeling the data with power exponential fits were unsuccessful in many cases and were complex, nonintuitive and of limited clinical utility. Accordingly, gastric emptying rates were determined by simple linear regression from geometric mean data. The starting index (the time at which the regression line equalled 100%) was calculated to reflect the lag phase. Normal ranges were determined for men and women.
  
  
  CONCLUSIONS
  Our method of test performance is simple, eliminates confounding variables and provides results with intuitive meaning and with direct clinical relevance.
authors.affiliation: Department of Radiology, University of Texas Medical Branch, Galveston 77555-07930.
authors.forename: M L
authors.initials: ML
authors.lastname: Nusynowitz
authors.forename: A R
authors.initials: AR
authors.lastname: Benedetto
mesh_terms: D000328:Adult; D005260:Female; D005746:Gastric Emptying / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D008961:Models, Structural; D008962:Models, Theoretical; D011877:Radionuclide Imaging; D012727:Sex Characteristics; D013270:Stomach / Q000000981:diagnostic imaging* / Q000502:physiology; D013671:Technetium Tc 99m Sulfur Colloid
chemical_list: D013671:Technetium Tc 99m Sulfur Colloid