Exercise-induced myocardial perfusion abnormalities in sickle beta-thalassemia: Tc-99m tetrofosmin gated SPECT imaging study.

PURPOSE: To determine the mechanism of myocardial ischemia in patients with sickle beta-thalassemia, we performed a scintigraphic evaluation of myocardial perfusion during exercise. SUBJECTS AND METHODS: We studied 30 patients with sickle beta-thalassemia, (mean [+/-SD] age, 37 +/- 10 years) who had no electrocardiographic (ECG), radiographic, or echo-Doppler signs of pulmonary hypertension, left ventricular hypertrophy, or impaired contractility. All patients had a hemoglobin level greater than 7 g/dL. Treadmill exercise test was performed according to the Bruce protocol. Myocardial perfusion was assessed by single-photon emission computed tomography, using Tetrofosmin Tc-99 m Myoview as radiotracer, at peak exercise and again 4 hours later. RESULTS: Eight patients (27%) developed stress-induced scintigraphic perfusion abnormalities that were reversible in all but 1 patient. Subsequent coronary angiograms were normal in all 8 patients. ST segment depression was seen during exercise in 5 of the 7 patients who had reversible perfusion defects. Except for a significantly greater white blood cell count, these 5 patients did not differ from the rest of patients by sex, age, hemoglobin level, percentage hemoglobin F, beta-thalassemia genotype, or risk factors for coronary artery disease. Three of the 5 patients with perfusion and ECG abnormalities (and another with only perfusion defects) developed a stress-induced sickling crisis. CONCLUSION: Physical stress may induce myocardial ischemia in sickle beta-thalassemia patients with normal coronary arteries and elicit painful crises. The sickling process, activated by exercise, could be the common underlying mechanism.

Mental stress-induced silent myocardial ischemia detected during ambulatory ventricular function monitoring.

BACKGROUND: Transient ischemic episodes at rest in patients with coronary artery disease have been attributed to mental stress. The means to monitor and record cardiac function changes due to mental stress is now available by utilizing the nuclear VEST. METHODS AND RESULTS: Eight, patients with angiographically documented coronary artery disease and 8 normal volunteers underwent a 4 hour session of continuous monitoring and recording of the left ventricular function, electrocardiogram, and blood pressure during exercise and mental stress. In the normal group, all subjects showed the expected normal response to exercise with an increase in ejection fraction, heart rate and blood pressure. During mental stress two subjects (25%) showed transient episodes of ejection fraction decrease that were not associated with chest pain, ST changes or significant changes in blood pressure. In the group of coronary artery disease patients, five (63%) had an ischemic response to exercise by electrocardiographic and radionuclide ventriculography criteria with evidence of chest pain in three of them. All of them revealed transient episodes of left ventricular dysfunction during mental stress. Episodes were painless, occurred at low heart rate and in most cases were accompanied by ST-segment changes. The rest of the patients with a normal response to exercise showed slight changes of the ejection fraction above the baseline. CONCLUSION: The results provide evidence that there is marked disparity in the incidence of chest pain and ST-segment changes, despite similar ischemic ejection fraction response between mental and physical stress. This is indicative of a major role of mental stress in provoking silent ischemia that potentially might provide additional clinical information compared to exercise test.

A composite score of enterogastric reflux quantitation on 99mTc-HIDA scintigraphy.

BACKGROUND/AIM: Enterogastric reflux of bile, and duodenal and pancreatic secretions may occur either spontaneously or, more commonly, after gastric surgery. The most reliable method in discriminating symptomatic from asymptomatic postgastric surgery refluxers, and in predicting a good clinical result after surgical diversion in the former group, is the quantitation of reflux by 99mTc-HIDA scintigraphy. MATERIALS AND METHODS: In 28 normal subjects and 143 postgastric surgery patients, the enterogastric reflux (EGR) was demonstrated by 99mTc-HIDA scintigraphy on 230 occasions. The EGR index was quantitated according to two different formulae: the former one based on the amount of refluxate (percentage of maximal radioactivity of the gastric area over the total abdominal activity--EGR-Im) and the latter one based on the amount and the duration of the time of reflux (CompEGR-Im) and representing the area of the surface below the curve, which was yield by plotting EGR-Im values (obtained every 5 min for one hour) against time. RESULTS: Although there was a highly significant correlation of values between the two methods (p<0.0000001), the latter one was more reliable in classifying postgastric surgery patients according to the presence of reflux symptoms and the reflux index. CONCLUSIONS: In patients with a CompEGRpIm>770 and postgastric surgery symptoms, at least some of the symptoms can be safely be attributed to enterogastric reflux.

Gallbladder emptying after antiulcer gastric surgery.

It has been shown that truncal vagotomy with pyloroplasty (TVP), but not highly selective vagotomy (HSV), delays the onset, decreases the extent, and changes the pattern of gallbladder emptying. The aim of the present study was to investigate any alterations in gallbladder emptying after a variety of antiulcer gastric surgery, by milk-technetium 99m (99mTc)-dimethyl iminodiacetic acid (HIDA) scintigraphy. After excluding the cases with spontaneous gallbladder evacuation before milk ingestion, there were 26 controls, 41 duodenal ulcer (DU) patients, 22 after HSV (15 prospective cases), 50 after TVP (23 prospective cases), 8 after TV with gastrojejunostomy (TV-GJ), 10 after Billroth I gastrectomy, and 29 after Billroth II gastrectomy. None of the patients with gastrectomy had additional vagotomy. TVP significantly delayed the onset and decreased the rate of gallbladder emptying as compared with the control, DU, HSV, and Billroth I groups. TVP also changed the pattern of emptying in 20% of the cases (sequential emptying and refilling events). Antiulcer operations excluding the duodenum (TV-GJ and Billroth II) further reduced the rate of gallbladder emptying as compared with (1) control, DU, HSV, and Billroth I groups (P < 0.0001) and (2) TVP (P < 0.001). Onset of gallbladder emptying was not affected by Billroth II gastrectomy, but was significantly delayed by TV-GJ (P < 0.001). The latter two operations also significantly changed the pattern of gallbladder emptying, exhibiting sequential emptying and refilling events, in most cases (P < 0.01 versus TVP). In conclusion, all antiulcer procedures, except HSV, greatly disturb the pattern, the onset, and the rate of gallbladder emptying. Truncal vagotomy seems to disrupt vagally mediated preduodenal mechanism, resulting in delayed onset and reduced rate, whereas duodenal exclusion by gastrojejunostomy results in severely decreased rate of gallbladder emptying.

Roux-en-Y gastroenterostomy severely disturbs emptying of the gallbladder.

BACKGROUND: It is documented that truncal vagotomy and Billroth II gastroenterostomy disturbs the emptying of the gallbladder. The aim of the present prospective study was to assess the emptying of the gallbladder after Roux-en-Y gastroenterostomy. STUDY DESIGN: There were 34 patients, who had undergone either truncal vagotomy with pyloroplasty (TVP, 14 instances) or Billroth II gastrectomy (20 instances), and were subsequently subjected to Roux-en-Y gastroenterostomy. The emptying of the gallbladder was assessed before and after the Roux-en-Y procedure, by milk-technetium-99m labeled hepatoiminodiacetic acid (milk-99mTc-HIDA) scintigraphy. Milk-99mTc-HIDA scintigraphy was also performed on twenty-eight healthy subjects, who served as the control group. RESULTS: After excluding the subjects having spontaneous gallbladder evacuation before milk ingestion, there remained 26 subjects in the control group, 12 patients with TVP, and 19 with Billroth II gastrectomy. Truncal vagotomy with pyloroplasty was associated with delayed onset (p < 0.001) and decreased rate (p < 0.01) of emptying of the gallbladder compared with the control group. Truncal vagotomy with pyloroplasty also changed the normal pattern of emptying in two patients (sequential emptying and refilling events). Billroth II gastrectomy was associated with decreased extent and abnormal pattern of emptying compared with subjects in the control group (p < 0.0001) and patients having TVP. Roux-en-Y gastroenterostomy, performed upon patients with TVP, significantly increased lag phase duration (p < 0.001), decreased ejection fraction (p < 0.01), and changed the pattern of emptying of the gallbladder (p < 0.01). Roux-en-Y procedure performed upon patients with Billroth II gastrectomy significantly increased lag phase duration (p < 0.0001). CONCLUSIONS: Roux-en-Y gastroenterostomy severely disturbs all parameters of the emptying of the gallbladder.

Reproducibility of gallbladder emptying scintigraphic studies.

UNLABELLED: This study was designed to investigate the reproducibility of the results obtained from 99mTc-dimethyliminodiacetic acid (99mTc-EHIDA) cholescintigraphy, when used as a method of estimating gallbladder emptying. METHODS: In a random controlled fashion, the reproducibility of scintigraphic gallbladder emptying studies was assessed in 30 subjects, of whom six were normal, four had duodenal ulcers and the remaining 20 had undergone antiulcer gastric surgery. In fasting subjects, who 30 min later drank 250 ml of fresh milk, 2 mCi of 99mTc-EHIDA was intravenously injected. Liver and gallbladder areas were scanned for 60 sec and then every 5 min for 1 hr. The study was repeated in all subjects within 2-5 wk. From the gallbladder emptying curves, the duration of the lag phase (time from milk ingestion to actual start of emptying), the ejection fraction of emptying (peak to least activity in the gallbladder), the time by which maximal emptying was achieved and the pattern of gallbladder emptying were calculated. RESULTS: Two subjects were excluded from the study because their gallbladders did not fill. Lag phase duration was well reproduced in duplicate studies (r = 0.87), as was ejection fraction (r = 0.84). The time by which maximal emptying was achieved was not sufficiently reproduced. The normal pattern of emptying (exponential function) was reproduced in all controls, subjects with duodenal ulcers and patients after antiulcer surgery that did not involve duodenal exclusion. The abnormal pattern of emptying, characterized by refilling, was reproduced in five of the seven patients with gastric surgery that mainly involved duodenal exclusion. CONCLUSION: Scintigraphy with 99mTc-EHIDA to assess gallbladder motility is a method with satisfactory reproducibility of both parametric variables and patterns of emptying.

Surgical treatment of the enterogastric reflux syndrome: preoperative and postoperative estimation by 99mTc-HIDA scintigraphy.

Twenty-nine patients with enterogastric reflux syndrome after anti-ulcer gastric surgery underwent a revisional Roux-en-Y gastrectomy. The diagnosis of enterogastric reflux syndrome was based on symptomatology and endoscopy in the first eight patients. The latter 21 patients had, in addition, a 99mTc-HIDA scintigraphy for the documentation and measurement of reflux. An enterogastric reflux index > 20 per cent is considered to justify symptoms due to reflux. Three of the first eight patients continued postoperatively to experience the same symptoms as before. These symptoms were eventually attributed to other than enterogastric reflux syndromes. The latter 21 patients were relieved from their preoperative symptoms and classified as Visick I and II (18 patients) and Visick III (3 patients). The authors conclude that enterogastric reflux syndrome must be documented on scintigraphy before the patient is subjected to revisional anti-reflux surgery in order for failures due to misdiagnosis to be avoided.

Erythromycin accelerates delayed gastric emptying of solids in patients after truncal vagotomy and pyloroplasty.

OBJECTIVE: To find out if erythromycin (a motilin agonist) accelerated gastric emptying after vagotomy and in normal subjects. DESIGN: Double blind controlled study. SETTING: Two referral centres. SUBJECTS: 15 patients who had previously undergone vagotomy and who did (n = 8) or did not (n = 7) have symptoms of gastric stasis and 10 normal controls. INTERVENTIONS: A standard meal containing 185 x 10(5) Bq -99mTc was eaten after either erythromycin 200 mg or 40 ml placebo (normal saline) had been given intravenously. Subjects were then scanned by gamma camera. MAIN OUTCOME MEASURES: Measurement of: the length of time from completion of the meal to the onset of gastric emptying; the length of time from completion of the meal until half of the meal had left the stomach; the length of the time from the onset of gastric emptying until half of the meal had left the stomach; and the percentage of the meal that was left in the stomach at 60 and 120 min after the end of the meal. RESULTS: Gastric emptying was significantly delayed in those patients with symptoms compared with normal subjects and patients without symptoms. Erythromycin accelerated the first two phases of gastric emptying in all patients and normal subjects, but did not affect the length of time from the onset of gastric emptying until half the meal had left the stomach. CONCLUSION: Erythromycin could be a useful gastrokinetic agent in patients with symptoms of gastric stasis after vagotomy.

Enterogastric reflux after various types of antiulcer gastric surgery: quantitation by 99mTc-HIDA scintigraphy.

In 28 controls and 142 patients subjected to a variety of antiulcer procedures, the enterogastric reflux (EGR) was quantitated by 99mTc-HIDA scintigraphy and expressed as the EGR index on 229 different occasions. The EGR index was calculated according to two different formulas: one based on the maximal radioactivity over the gastric area as a percentage value of the total abdominal activity (EGR-Im) and the other based on the relative maximal radioactivity over the gastric area as a percentage value of the relative hepatobiliary activity (EGR-It). There was a significant positive correlation of values between the two methods (P less than 0.0001). In patients with an EGR-Im greater than 20% or EGR-It greater than 57% and postgastric surgery symptoms some of the symptoms were attributed to EGR, an antireflux procedure is expected to relieve those symptoms. Sixteen of these patients underwent Roux-en-Y gastrectomy and their preoperative symptoms were relieved.

Detection of coronary artery disease by analysis of ventricular filling.

Rapid left-ventricular (LV) diastolic filling assessed by radionuclide ventriculography is reevaluated in patients with coronary artery disease and normal LV systolic function considering the effects of age and heart rate. Thirty normal subjects were studied along with 44 patients with coronary artery disease and normal LV ejection fractions. The peak filling rate was not quite significantly different between the controls and patients (2.67 +/- 0.95 EDV/sec versus 2.25 +/- 0.65 EDV/sec, p = 0.08), and the time to peak filling rate was not different. When an inappropriate young control group was compared with coronary disease patients aged 40-65 yr, large differences in peak filling rate were seen. Sensitivity for detection of disease was very low (0%-9%) except when the inappropriate young control group was used. Thus, analysis of rapid diastolic filling cannot detect individual patients with coronary disease who have normal LV ejection fractions. Previous reports to the contrary may have suffered from failure to include the effects of age and heart rate.

Alterations in serum gastrin levels and antral G- and D-cell population following extensive proximal small bowel resection (radioimmunoassay and immunocytochemical study in dogs).

Twelve dogs underwent an extensive proximal small bowel resection. Basal and postprandial serum gastrin levels increased significantly one and two months after the resection compared to the respective preoperative levels. The increase in serum gastrin levels two months after the resection was less prominent than the respective increase one month postoperatively. Antral G- and D-cell populations increased significantly two months after the resection compared to the respective populations before the resection. It is concluded that hypergastrinaemia following small bowel resection is due to the quantitative elimination of the inhibiting hormonal factors of gastric secretion and gastrin release. The adaptive increase of antral D-cell population could explain the temporary character of hypergastrinaemia.

Alterations in serum gastrin levels and antral G- and D-cell population following corticosteroid administration. RIA and immunocytochemical long-term study in guinea pigs.

Fourteen guinea pigs were given prednisolone daily for 20 days and 11 for 40 days. Another 20 formed the two control groups. Short-term prednisolone treatment significantly increased serum gastrin levels and antral G-cell population as compared to the control group. The same parameters significantly decreased following 40 days of prednisolone treatment as compared to the group of short-term prednisolone treatment. Forty days of prednisolone treatment significantly increased antral D-cell population as compared to the control and short-term prednisolone treatment groups. It is concluded that hypergastrinaemia and antral G-cell hyperplasia following corticosteroid administration is temporary and is accompanied by antral D-cell hyperplasia.

Sex related differences in serum gastrin concentrations and G- and D-cell populations of the gastric mucosa in guinea-pigs (experimental RIA and immunocytochemical study).

In the present study antral G-cells which secrete gastrin and antral and fundic D-cells which secret somatostatin, an inhibitor of gastric acid secretion were revealed immunocytochemically and the population size estimated along with serum gastrin levels in ten male and eight female guinea pigs. Serum gastrin, antral G-cells, antral D-cells and fundic D-cells were 41.90 +/- 6.10 SD pg/ml, 210 +/- 18.03 SD cells/cm, 128.20 +/- 17.64 SD cells/cm and 121 +/- 17.91 SD cells/cm respectively in males and 35 +/- 4.62 SD pg/ml, 176 +/- 13.80 SD cells/cm, 108.40 +/- 6.90 SD cells/cm and 106.8 +/- 6.50 SD cells/cm respectively in females. The differences in serum gastrin levels, antral G-cell population and antral D-cell population between the two sexes were statistically significant (P less than 0.05, P less than 0.001, P less than 0.01). It is possible that endogenous androgens induce a relative hyperplasia and endogenous oestrogens a relative hypoplasia of G-cells. Antral D-cell differences may reflect an adaptive hormonal mechanism to the possible different states of gastric secretory functions.

A multiobserver comparison of 99mTcO4 and 123I thyroid imaging.

The thyroids of forty patients were imaged using 2 mCi(74 MBq) 99mTc pertechnetate (99mTcO4) followed within one week by 2 mCi (74 MBq) 123I Iodide. The images obtained were evaluated by eight observers for 6 morphological criteria and assigned to 6 diagnostic categories with a confidence grading on a seven level scale (grade 1 being that for maximum confidence). Images were obtained with 123I for the same counts and the same times as those with 99mTcO4 and compared using an index in which the number of diagnostic categories and the mean confidence grading within each category were taken into account. The mean index obtained for 99mTcO4 images (9.2) was significantly greater (P less than 0.05, thus representing a lower observer confidence and less interobserver diagnostic agreement) than the mean indices for 123I equal count images (5.6) and 123I equal time images (6.8). The diagnoses made on the basis of 123I images were more frequently concordant with the final diagnosis after six months follow up (75% for equal counts and 77% for equal time) than those with 99mTcO4(63%). The radioisotope of iodine most suited to modern nuclear medicine instrumentation and with the most favourable radiation dosimetry is 123I which is recommended for those areas of thyroid imaging where iodine is superior.