Computer analysis of radionuclide esophageal transit studies.

For detailed examination of the esophageal transit of a swallowed radioactive liquid bolus, three computer-based techniques have been developed: (a) analysis of time-activity curves with decomposition into rapid and residual components, yielding the mean transit time for the former and the residual fraction for the latter; (b) reduction of dynamic image sequences to single condensed images, facilitating subjective assessment; and (c) tracking of the centroid of radioactivity, permitting quantification of retrograde motion. Studies were performed on 12 normal subjects and on six patients with motility disorders. Elevated residual fractions were observed in all the patients, and an abnormal degree of retrograde motion in two. Two normal and two abnormal studies exemplify the variety of patterns observed in condensed images.