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Experience with a simplified, standardized 4-hour gastric-emptying protocol
- Source :
- Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 48(4)
- Publication Year :
- 2007
-
Abstract
- Gastric-emptying studies have no accepted standard methodology or reference values. A simplified standardized protocol with a large reference database has been proposed, with imaging obtained at only 0, 1, 2, and 4 h. The rationale for its 4-h length is data suggesting that delayed emptying is detected with higher sensitivity at 4 h than at 2 h. The purpose of the current investigation was to review our 2-y experience using this protocol, to determine the added value of 4-h imaging, and to determine whether the lag phase can predict delayed emptying.After ingesting a sandwich made with (99m)Tc-sulfur colloid egg substitute, 175 patients were imaged immediately, every 10 min for 1 h, and then at 2, 3, and 4 h. Percentage retention was calculated for each interval. Sensitivities, specificities, predictive values, and receiver operating characteristic (ROC) curves were computed for the 1-, 2-, and 3-h intervals on the basis of normal 4-h values. Data were analyzed to determine the added value of the 4-h study. Thresholds were sought that optimized accuracy. ROC analysis was used to determine the predictive value of the lag phase.Gastric emptying was delayed in 20% of patients at 2 h and in 26% at 4 h, a 29% increase in abnormal studies (P0.02). Of those normal at 2 h, 13% became abnormal at 4 h. Of those with delayed emptying at 2 h, 24% normalized at 4 h. Compared with the study at 4 h, the study at 2 h had a 59% sensitivity, 94% specificity, 76% PPV, and 87% NPV. ROC analysis showed that the areas under the ROC curve (AUC) were 0.75, 0.93, and 0.97 at 1, 2, and 3 h, respectively. The threshold for optimal accuracy for 3-h data was estimated to be greater than 30% retention. The accuracy of this threshold was 91%. The lag phase AUC for predicting delayed emptying at 4 h was 0.60.This first investigation of a large referral patient population using a standardized protocol found that abnormal emptying is detected with greater sensitivity at 4 h than at 2 h and that the lag phase is not predictive of delayed emptying.
- Subjects :
- Adult
Male
medicine.medical_specialty
Time Factors
Adolescent
Sensitivity and Specificity
Predictive Value of Tests
Medicine
Humans
Radiology, Nuclear Medicine and imaging
Gastroparesis
Aged
Protocol (science)
Aged, 80 and over
Gastric emptying
Receiver operating characteristic
business.industry
Reproducibility of Results
Middle Aged
medicine.disease
Surgery
Gastric Emptying
ROC Curve
Predictive value of tests
Reference values
Area Under Curve
Egg substitute
Reference database
Female
business
Nuclear medicine
Subjects
Details
- ISSN :
- 01615505
- Volume :
- 48
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- Journal of nuclear medicine : official publication, Society of Nuclear Medicine
- Accession number :
- edsair.doi.dedup.....4c02ddf83af1f0003c1a884ef324b681