Gastric emptying and small-bowel transit rate in the elderly.

Gastric emptying of liquid and small bowel transit in a group of elderly patients (mean age 79 years) was studied, with the elderly subjects compared to two groups of young controls. In 14 elderly patients, the initial rate of gastric emptying was significantly higher than in 14 young controls: the five-minute volume was 159 +/- 30 ml (mean +/- SEM) in the elderly patients and 294 +/- 22 ml in the young controls (p less than 0.005). The two groups' gastric emptying rates after five minutes were not significantly different. Small-bowel transit in 15 elderly patients was not significantly different from that found in 15 younger volunteers. These results suggest that gastric homeostatic mechanisms are impaired in the elderly.

Clinical evaluation of computer processing of liver gamma camera scans.

A prospective study to assess the clinical usefulness of computer processing of liver scans has been carried out on 203 patients. All patients have had six months follow up to confirm the diagnostic accuracy of the scan results. Four presentations have been studied using ROC analysis: (i) original gamma-camera pictures; (ii) processed images obtained using a non-stationary filter; (iii) images processed using nine-point smoothing; (iv) images obtained by linear interpolation at 25 isocount levels of display. It is concluded that pictures obtained by use of a non-stationary filter at 25 isocount levels are superior to a conventional gamma-camera pictures and displays obtained by linear interpolation only. All three are considerably superior to the images obtained by nine-point smoothing in detection of focal space-occupying lesions. Based on the results obtained, a strategy for the rational use of computer processing of gamma-camera liver scans is proposed.

The importance and required detection levels of radionuclide impurities--a medical physicist's view.

All radioactive impurities in radiopharmaceuticals contribute unnecessary radiation dose to the patient. gamma-Emitting impurities can adversely affect the quality of gamma-camera images and measurements of organ and sample radioactivity and can interfere with concurrent and subsequent nuclear medicine procedures. Full specification of radionuclidic content of all radiopharmaceuticals would help the user to avoid or minimise these effects. Detection levels of 1 in 10(6), and for alpha emitters 1 in 10(9), are required of suppliers and monitoring laboratories.

The distribution and enteric loss of 51Cr-labelled lymphocytes in normal subjects and in patients with coeliac disease and other disorders of the small intestine.

Peripherally harvested lymphocytes have been labelled with 51Cr, reinjected into human subjects and their distribution then studied. Evidence is presented which suggests faecal loss of 51Cr represents loss of T lymphocytes and that there is normally a pathway of lymphocyte removal into the gut of probable importance in lymphocyte migration streams. In 9 normal subjects, without structural intestinal disease, faecal loss of lymphocytes over 5 days was 0.20% (SEM +/- 0.06) whereas in 5 patients with untreated coeliac disease faecal loss was 1.13 +/- 0.34%, in 7 with Crohn's disease it was 1.01 +/- 0.21% and in 5 with intestinal lymphangiectasia loss was 0.61 +/- 0.10%. In 1 patient with acute tropical sprue, enteric loss was 0.97%. By contrast, faecal loss was normal in 3 coeliac patients in remission on a gluten-free diet. Measurements were also made using an external counter. In contrast to the normals, where count rates steadily diminished, an increasing activity was recorded over the umbilicus over 7 days after dose administration in all the disease categories studied with the exception of the treated coeliacs. The finding of an increased enteric loss of lymphocytes may explain many of the immunological abnormalities in the conditions studied.

Clinical usefulness of computer controlled presentation in isocount levels of gamma camera liver scans.

Results of investigations comparing computer displays in isocount levels with ordinary gamma camera scans are presented. The study on 109 patients with 12 month follow up shows that isocount level 25 is the best to see a smoothed out image of liver and is superior to conventional polaroid gamma camera scan in picking out more focal lesions (P less than 0.05).

Severe hypertension in primary aldosteronism and good response to surgery.

11 patients with primary aldosteronism have been encountered over 11 years and submitted to surgery in a provincial teaching hospital serving a population of 3 million. Contrary to classical teaching, the hypertension has usually been very severe. Precise identification of the site of the lesion preoperatively has been possible by the measurement of adrenal-vein aldosterone levels, and results of surgery have been excellent. The iodocholesterol adrenal scan also correctly identified the site of the adenoma in 5 out of 7 patients in which it was used. Adrenal venography was of little value except in siting catheters.