Multicenter validation of a shortened gastric-emptying protocol.

UNLABELLED: Gastric emptying scintigraphy is considered to be the gold standard for detection of gastroparesis and other disorders of gastric motility; Society of Nuclear Medicine and Molecular Imaging guidelines are predicated on imaging over a period of 4 h, which is inconvenient for patients. Bonta et al. introduced 2-h criteria, which served to shorten the protocol in most patients, with negligible loss of accuracy. We have evaluated the Bonta criteria in a larger multicenter trial encompassing 4 academic institutions. METHODS: Retrospective data from 4 academic medical centers were aggregated; 431 patients were included, 105 (24.4%) of whom demonstrated delayed gastric emptying defined by 4-h gastric retention of more than 10%. Bonta criteria (retention > 65% is considered abnormal and < 45% normal; otherwise, proceed to complete examination) were applied to the 2-h data. Sensitivity, specificity, accuracy, and resource use for the Bonta method were calculated. Results based on standard 4-h solid gastric emptying, performed according to current Society of Nuclear Medicine and Molecular Imaging guidelines, served as the gold standard. RESULTS: Retention of 10% or less was achieved by 6, 77, 215, and 326 patients at 1, 2, 3, and 4 h, respectively. At 2 h, 261 of 431 patients (60.6%) had gastric retention of less than 45%, which according to Bonta would be classified as normal; 62 (14.4%) had gastric retention of more than 65%, which would be classified as delayed emptying; and 108 (25.1%) had intermediate values requiring further imaging through 4 h. The Bonta criteria yielded a sensitivity, specificity, and accuracy of 92.4%, 96.9%, and 95.8%, respectively, superior to any single cutoff point applied to the 2-h values. The criteria resulted in false-negative results in 8 (1.9%) patients, 6 of whom were borderline-positive at 4 h (gastric retention of 11%-14%). Using the Bonta criteria, 74.9% of studies would be terminated by 2 h, decreasing total camera use by 15.7%, from 1,768 to 1,490 images, and the average study duration would be reduced by 20.6%, from 3.1 to 2.5 h. CONCLUSION: In a multicenter cohort, use of the Bonta criteria shortened the duration of studies in most patients, resulting in an effective compromise between reduced resource use, improved patient convenience, and preserved accuracy.

Planar scintigraphic imaging of the gastrointestinal tract in clinical practice.

In the last 30 years, nuclear medicine has paralleled other imaging fields with the development of 3-dimensional techniques, including single-photon emission computed tomography and positron emission tomography. However, conventional nuclear medicine planar scintigraphy remains a common procedure at most imaging centers. Gastrointestinal studies constitute a significant portion of these planar procedures. The most common gastrointestinal studies, including hepatobiliary, gastric emptying, and gastrointestinal bleeding evaluations, resemble their original protocol. However, serial improvements have optimized the diagnostic efficacy of these procedures. Conventional Technetium-99m sulfur colloid liver/spleen imaging and hepatic blood pool imaging with labeled red blood cells now mainly serve an adjunctive role in the evaluation of equivocal findings on computed tomography. Salivary gland imaging is a less commonly requested evaluation, but can be used to evaluate functional capacity in some disease entities.

Nuclear medicine applications in the clinical setting. Imaging studies aid disease staging and management.

Over the last decade, advances in instrumentation have improved the accuracy and quality of conventional nuclear medicine studies. In addition, the approval of many new radiopharmaceuticals has helped integrate cutting-edge imaging techniques into the clinical setting. In this article, Drs Middleton and Shell discuss the latest applications of positron emission tomography (PET), radiolabeled antibody imaging, radioisotope lymphatic mapping, and radiolabeled receptor imaging.