Clinical use of 24-hour gastric pH monitoring vs o-diisopropyl iminodiacetic acid (DISIDA) scanning in the diagnosis of pathologic duodenogastric reflux.

The efficacy of o-diisopropyl iminodiacetic acid (DISIDA) scanning was compared with that of computerized analysis of 24-hour gastric pH monitoring to diagnose excessive duodenogastric reflux in 22 normal volunteers and 106 consecutive patients with foregut symptoms. DISIDA scanning had a false-positive rate of 18% in the normal volunteers. Gastric pH monitoring showed an increasing prevalence of duodenogastric reflux in patients with increasing clinical evidence of this condition, which was not seen with DISIDA scanning. Both DISIDA scanning and gastric pH monitoring identified duodenogastric reflux in most patients who had had previous pyloroplasty or antrectomy. Only gastric pH monitoring, however, showed a significantly increased prevalence of duodenogastric reflux in symptomatic patients after previous cholecystectomy compared with those who had not undergone previous surgery. These data suggest that 24-hour gastric pH monitoring is superior to DISIDA scanning in identifying duodenogastric reflux as a cause of foregut symptoms.