Multicenter validation of a shortened gastric-emptying protocol

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.

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.

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.

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.