Peter J. Collins

Gastric emptying in normal subjects--a reproducible technique using a single scintillation camera and computer system.

The gastric emptying of a mixed solid and liquid meal was assessed in 24 normal subjects using a single camera/computer system which allowed continuous monitoring of both solids and liquids. It was shown that variation in tissue attenuation caused by the changing depth of radionuclide within the stomach accounted for large errors in the measurement of gastric emptying (alteration in 50% emptying time of up to 65%). A technique for the correction of attenuation is described which used factors derived from a lateral image of the stomach. In all subjects, solid emptying was slower than liquid emptying and was characterised by a delay (lag period) which was followed by linear emptying. Liquid emptying usually followed a single exponential pattern. The effect of physiological changes induced by increasing the calorie content of the liquid component of the meal was assessed by giving either water, 10% dextrose or 25% dextrose. Liquid emptying was slowed and the lag period of solid was prolonged as the calorie content increased. Reproducibility was assessed in 19 subjects. For the three groups studied (water, 10% dextrose, 25% dextrose) the day-to-day variation in gastric emptying was not significant for any measured parameter, while statistically significant differences were present in solid and liquid emptying between subjects and groups.

Acute and chronic effects of domperidone on gastric emptying in diabetic autonomic neuropathy

Gastric emptying was studied with a double radioisotopic method in 12 patients with insulin-dependent diabetes mellitus complicated by autonomic neuropathy and in 22 control subjects. In the diabetics, the acute and chronic effects of oral domperidone on gastric emptying, symptoms of gastroparesis, and glycemic control were assessed. Gastric emptying of solid and liquid was slower in diabetics than controls (P<0.001). Acute administration of domperidone increased the rate of both solid and liquid emptying (P<0.005). Domperidone was most effective in those patients with the greatest delay in gastric emptying. After chronic administration (35–51 days), domperidone had no significant effect on solid emptying (P>0.05), but was still effective in increasing liquid emptying (P<0.025). Symptoms of gastroparesis were less after domperidone (P<0.001).

Motor mechanisms associated with slowing of the gastric emptying of a solid meal by an intraduodenal lipid infusion

The aim of this study was to define better the motor phenomena associated with the slowing of gastric emptying by a duodenal lipid infusion. Antral, pyloric and duodenal motility were recorded in 10 healthy subjects with a manometric assembly which incorporated multiple perfused side‐holes and a sleeve sensor positioned astride the pylorus. The gastric emptying of a standard solid meal and the distribution of the ingesta between the proximal and distal stomach were monitored with a radionuclide technique. A triglyceride emulsion was infused into the duodenum for 45 min once 25% of the meal had emptied. The infusion caused significant slowing in the rate of gastric emptying (P < 0.01). This slowing in gastric emptying was associated with the suppression of pressure waves in the distal antrum (P < 0.01) and proximal duodenum (P < 0.01), the induction of pressure waves isolated to a narrow pyloric segment (P < 0.01), and a redistribution of ingesta from the distal to proximal stomach. These findings suggest that pressure waves isolated to the pylorus, changes in the intragastric distribution of ingested food, and changes in proximal duodenal motility may all act in concert with changes in antral motility to regulate the gastric emptying of solids.

Role of the proximal and distal stomach in mixed solid and liquid meal emptying.

The role of the proximal and distal stomach in the emptying of solids and liquids from the stomach remains unclear. We have used a dual isotope technique to quantify proximal and distal stomach emptying of a solid (100 g of 99mTc labelled liver/ground beef) liquid (either 200 ml of normal saline (eight subjects) or 25% dextrose (seven subjects) labelled with 113mIn-diethylenetriaminepenta-acetic acid) mixed meal. A manometric catheter simultaneously measured antral, pyloric, and duodenal motor activity. The liquid component dispersed rapidly throughout the stomach and emptied after a minimal lag period. The emptying of the 25% dextrose was delayed compared with the saline. This delay was associated with increased retention of the liquid in the distal stomach, a significant increase in localised phasic pyloric contractions, and a suppression of antral contractions. The solid component initially resided wholly within a proximal stomach reservoir area. Solids then redistributed from proximal to distal stomach during the emptying of liquid from the stomach. Dextrose delayed gastric emptying of solids compared with saline by increasing the solid lag period and retention in the proximal stomach. There was no significant difference between saline and dextrose meals in the distal stomach retention of solid or in the linear rate of emptying after the lag period. We conclude that, contrary to general opinion, the proximal stomach plays an important role in the control of gastric emptying of solids while the distal stomach is important in the emptying of nutrient liquids.

Gastric and oesophageal emptying in insulin-dependent diabetes mellitus

Abstract Gastric emptying of a digestible solid and liquid meal and oesophageal emptying of a solid bolus were measured with scintigraphic techniques in 45 randomly selected insulin‐dependent diabetics and in 22 control subjects. In the diabetics, the relationships between oesophageal emptying, gastric emptying, age, duration of diabetes mellitus, upper gastrointestinal symptoms, glycaemic control and the complications, autonomic neuropathy, peripheral neuropathy and retinopathy were examined. The lag period before solid food left the stomach was not significantly different in diabetics compared with control subjects, but the percentage retention of solid food at 100 min was greater (P < 0.001) in the diabetic subjects. Both the early phase (percentage retention at 10 min) and the 50% emptying time for liquid gastric emptying were delayed (P < 0.001) in the diabetic subjects. Of the diabetics, 58% had delayed gastric emptying of either the solid and/or the liquid meal; oesophageal emptying was delayed in 42%. Upper gastrointestinal symptoms correlated poorly with both gastric and oesophageal emptying. Oesophageal emptying, solid gastric emptying and the liquid 50% emptying time correlated with the severity of autonomic nerve dysfunction (P < 0.05). The early phase of liquid emptying (retention at 10 min) was significantly slower (P < 0.05) in patients with mean plasma glucose concentrations of > 15 mmol/l during the gastric emptying test and the lag period for solid emptying correlated with both the glycosylated haemoglobin and mean plasma glucose concentrations.

Gastric and Oesophageal Emptying in Obesity

Gastric and oesophageal emptying were evaluated in 31 obese patients and 31 control subjects. A double-isotope technique was used to measure gastric emptying of a mixed solid/liquid meal, and oesophageal emptying was measured as the time taken for a bolus of the solid meal to enter the stomach. Gastric emptying of the solid (p less than 0.001) and the liquid (p less than 0.02) meal and oesophageal emptying (p less than 0.001) were delayed in the obese patients compared with the control subjects. There were no significant relationships among gastric emptying, oesophageal emptying, and upper gastrointestinal symptoms in the obese patients alone, but in the total group of 62 subjects there were significant correlations between body mass index and both gastric (r = 0.44, p less than 0.01) and oesophageal (r = 0.45, p less than 0.001) emptying. These results indicate that delayed gastric and oesophageal emptying occurs frequently in obesity and that these abnormalities relate to body weight.

Abnormalities of gastric and esophageal emptying in polymyositis and dermatomyositis

Gastric and esophageal emptying were assessed using scintigraphic techniques in 13 patients with polymyositis or dermatomyositis and in 13 normal volunteers. Esophageal emptying was significantly delayed in patients, with 8 of 13 patients being outside the normal range. Gastric emptying was also markedly slower in patients than in controls, with 8 patients being outside the normal range for solid emptying and 8 patients beyond the normal range for liquid emptying. The 5 patients with dysphagia all had delayed esophageal emptying, but both gastric and esophageal emptying were delayed in some asymptomatic patients. There was a significant correlation between esophageal emptying and both solid and liquid gastric emptying in the patients. Both gastric and esophageal emptying correlated with the severity of the peripheral (skeletal) muscle weakness. These results indicate that profoundly delayed gastric and esophageal emptying are common in polymyositis and dermatomyositis, implying frequent malfunction of the smooth muscle of the upper gastrointestinal tract in this disease.

Proximal, distal and total stomach emptying of a digestible solid meal in normal subjects

The gastric fundus and antrum probably play different roles in the emptying of solids and liquids in man, but there is little information about the intragastric distribution of food. We have used a new radionuclide technique to quantify proximal, distal and total stomach emptying of a digestible solid meal (100 g of 99Tcm-labelled liver/ground beef given with 150 ml of 10% dextrose) in 13 normal subjects. A proximal reservoir area was seen after consumption of the meal, and used to define the proximal stomach region. A line drawn immediately below this area divided the total stomach region into proximal and distal stomach. Emptying from the total stomach exhibited two phases--an initial lag period (median 41 min, range 21-57 min), followed by approximately linear emptying. Redistribution of food from the proximal to the distal stomach was a major component of the lag period in 11 of the 13 subjects. In the remaining two subjects, redistribution was rapid (proximal 50% emptying time of 4 and 10 min) and antral retention was the major component of the lag period. In seven subjects, a region of reduced activity (contraction band) was seen. The midpoint of this band closely approximated to the line used to divide proximal and distal stomach. We suggest that a contraction band may be responsible for the proximal gastric reservoir seen after meal consumption and plays an important role in the redistribution and emptying of digestible solid food from the stomach. There is considerable variation between normal subjects in the rate of transfer of digestible solid food from the proximal to the distal stomach.

The normal menstrual cycle has no effect on gastric emptying.

Summary. Recent studies have demonstrated that orocaecal transit time is prolonged both in the luteal phase of the ovulatory cycle in normal women and during pregnancy, but have made no attempt to differentiate between the individual effects of gastric emptying and small intestinal transit. We have assessed the effect of the normal menstrual cycle on gastric emptying of solids and liquids in 10 women, using a dual isotope scintigraphic technique. In each subject gastric emptying was measured on 2 days: first during the follicular phase (day 8–10) and then during the luteal phase (day 18–20) of one ovulatory menstrual cycle (where day 1 was the first day of menstrual bleeding). Measures of solid and liquid gastric emptying did not change significantly between the follicular and luteal phases indicating that the normal menstrual cycle has no effect on gastric emptying.

Correction for tissue attenuation in radionuclide gastric emptying studies: a comparison of a lateral image method and a geometric mean method

Variation in depth of radionuclide within the stomach may result in a significant error in the measurement of gastric emptying if no attempt is made to correct for gamma-ray attenuation by the patients tissues. In this study a method of attenuation correction, which uses a single posteriorly located scintillation camera and correction factors derived from a lateral image of the stomach, was compared with a two-camera geometric mean method, both in phantom studies and in five volunteer subjects. A meal of 100 g of ground beef containing 99Tcm-chicken liver, and 150 ml of water, was used in the in vivo studies. In all subjects the geometric mean data showed that solid food emptied in two phases: an initial lag period, followed by a linear emptying phase. Using the geometric mean data as a standard, the anterior camera overestimated the 50% emptying time (T50) by an average of 15% (range 5-18) and the posterior camera underestimated this parameter by 15% (4-22). The posterior data, corrected for attenuation using the lateral image method, underestimated the T50 by 2% (-7 to +7). The difference in the distances of the proximal and distal stomach from the posterior detector was large in all subjects (mean 5.7 cm, range 3.9-7.4). We conclude that attenuation effects may account for large errors in the measurement of gastric emptying with radionuclide methods and that the application of correction factors derived from a lateral image of the stomach reduces these errors.