Visualization of gastric bands on radionuclide gastric emptying studies

In the course of performing many gastric emptying studies with radionuclide labeled solid and liquid meals, the authors have noted the appearance of gastric ''bands'' on images. These bands do not appear to be peristaltic contractions because they persist in individual subjects for hours of imaging. Peristaltic contraction waves move and change appearance within a few seconds. Bands have been described in humans at autopsy and in dogs, pigs, and monkeys, typically in transverse and mid-gastric locations. However, because the bands have not been seen on radiographic studies with barium meals, the finding has been ignored in gastro-intestinal and radiologic textbooks. An anatomic basis or physiologic role in regulating gastric emptying is unknown. SPECT imaging of 5 normal subjects after ingestion of Tc-99m sulfur colloid labeled chicken liver meals on two separate study days was performed. Linear photon deficient regions (''bands'') were identified on gastric images in all subjects. Multiple bands were sometimes seen, including a transverse band across the mid lower body of the stomach and a vertical longitudinal band which appeared to bisect the fundus in three subjects. In one subject, multiple body positions including upright, upside-down, and supine, did not alter the appearance or location of themore » transverse gastric band. Conventional imaging did not always demonstrate presence of the band, since the optimal projection for imaging the band may not have been part of the planar imaging routine. Sixty-four acquisitions over 360/sup 0/ of SPECT imaging showed that bands were seen in some projections and not in others.« less