Esophageal involvement is common in systemic sclerosis, and esophageal scintigraphy can be used to detect and follow esophageal dysfunction. This study assesses the value of visual and quantitative analysis of esophageal scintigraphy performed as a multiple swallow test in normals and patients with systemic sclerosis.
Methods: Forty patients with systemic sclerosis and 40 sex- and age-matched healthy subjects (controls) were studied. A multiple swallow technique was used and both quantitative and qualitative analyses were performed. Visual analysis of condensed images was performed independently by two physicians. Each swallow was assigned a score on a scale from 1 to 4. In the quantitative analysis, time-activity curves based on the mean condensed images were used to calculate the following 3 parameters: residual activity 12 or 25 sec after the beginning of the swallow, measured with or without baseline correction, respectively, and time from onset of swallow to 50% of peak activity.
Results: Both visual and quantitative analysis showed a highly significant (p < 0.001) difference between the patient group and the control group. Visual analysis was best reflected by the residual activity 25 sec after the beginning of the swallow without correction for background. Receiver operating characteristic curves were used to study the ability to separate the two groups using visual or quantitative analysis. A high rate of positive tests in the patient group was achieved only at the cost of a relatively high rate of positive tests in the control group.
Conclusion: Our results indicate high variability in esophageal motility in controls. This variability impairs the possibilities of developing a screening test to identify asymptomatic patients early in the disease course.