Right on track? Performance of satellite telemetry in terrestrial wildlife research.

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.

Pulmonary scintigraphy in suspected pulmonary embolism: how often does it change clinical management?

The effect of pulmonary scintigraphy on patient management in suspected pulmonary embolism has been assessed in 158 patients. A change in management occurred in 30% following scintigraphy. The major effect was a reduction in the total number of patients who were anticoagulated. Heparin was stopped in 42 of the 74 patients to whom it had been administered prior to the scintigram.

Changes in arterial oxygen saturation during isotope perfusion scans using human macroaggregates of albumin.

Sixty-three patients undergoing isotope ventilation/perfusion scintigraphy for suspected pulmonary embolism were monitored using pulse oximetry. Xenon inhalation had no adverse effect on arterial oxygen saturation. Fifty-seven per cent of patients demonstrated a drop in oxygen saturation of 2-10% within 5 min of injection of macroaggregates. Small changes in arterial oxygen saturation reflect larger changes in the arteriole partial pressure of oxygen. In 10 patients, oxygen saturation dropped to 91% and below, corresponding to an arterial pO2 of less than 60 mm Hg. The effect lasted up to 30 min and is thought unlikely to be simply due to arteriolar blockade. Falls in arterial oxygen saturation cannot be correlated with any specific pulmonary pathology and appear unlikely to be of any clinical significance in most patients.

Gastric emptying and small bowel transit in male volunteers after i.m. ketorolac and morphine.

Ten male volunteers were studied in a randomized, double-blind crossover trial. Each received ketorolac tromethamine 30 mg and morphine sulphate 10 mg i.m. at an interval of 2 weeks. After a standard radiolabelled meal, gastric emptying half-time (GE) and small intestinal transit time (SIT) were measured using a gamma camera. Small intestinal transit time was measured also from end-tidal breath hydrogen (ETH), and overall gastrointestinal motility by time to first flatus (TFF). Mean GE, SIT and TFF were significantly prolonged by morphine compared with ketorolac (P less than 0.03); ETH was prolonged also, but the difference was not significant. There were no significant correlations between SIT, ETH and TFF. Most subjects reported adverse effects after morphine, but only one after ketorolac.

Survey on the use of pulmonary scintigraphy and angiography for suspected pulmonary thromboembolism in the UK.

A survey of UK radiologists in 360 acute hospitals was undertaken to assess the current use of pulmonary angiography and radionuclide lung scanning in the investigation of suspected pulmonary thromboembolism (PTE). Replies were received from 340 (94%) hospitals, of which 48 (out of 50) were teaching hospitals or centres which perform cardiothoracic surgery. Lung scintigraphy was provided by 200 (59%) hospitals and angiography by 120 (35%), with 99 (29%) providing both. Twenty-two hospitals which could undertake angiography had not performed more than one angiogram for suspected PTE in the preceding 3 years. Average numbers of lung scans performed in each hospital were 21.8 per month, in contrast with an average of 4.1 angiograms (including digital subtraction angiography) per year performed for suspected PTE over the previous 3 years. The total number of V/Q lung scans performed for the diagnosis of PTE per year was approximately 47,000 compared with 490 pulmonary angiograms.

Ventilation agents--what agents are currently used?

A survey of radiologists and nuclear physicians in 360 hospitals in the UK was undertaken to assess the current use of pulmonary ventilation agents. Replies were received from 340 (94%) hospitals. Of these, 200 (59%) provided lung scanning. The agents used for ventilation studies were Tc-labelled aerosols (118, 59%), 81Krm (58, 29%), 133Xe (42, 21%) and 127Xe (4, 2%). Nine (4.5%) hospitals performed perfusion scintigraphy without providing ventilation imaging. Thirty-two (16%) hospitals used more than one agent for ventilation imaging.

Paraileostomy hernia: a clinical and radiological study.

Forty-six patients who underwent colectomy with end ileostomy for ulcerative colitis (n = 33) or Crohn's disease (n = 13) have been reviewed for paraileostomy hernia (PIH) formation 1-16 years after surgery. PIH developed in 13 of these patients (28 per cent) and was not related to the original disease or excessive weight gain. Twenty-eight patients underwent limited computed tomography (CT) scanning of the stomal region. Eight of these had a clinically detectable PIH, which was demonstrated on CT. A further two patients had PIH demonstrated on CT which was not detected by clinical examination. The rate of PIH was similar where the stoma emerged lateral to the rectus abdominis muscle (six out of 16 patients, 37 per cent) to where the stoma emerged through the rectus (four out of 12 patients, 33 per cent). Recurrence following operative repair of PIH was common. PIH occurs more frequently than previously supposed. CT can detect PIH and may be useful in evaluating a patient with stoma-related symptoms for occult PIH formation.

Demonstration of para-ileostomy herniation using computed tomography.

Twenty-eight patients with end ileostomies underwent localised computed tomography (CT) of the ileostomy region. Para-ileostomy herniation was demonstrated in 10 patients. In two of these the hernia was not detectable clinically. This incidence (36%) is higher than that reported previously. Herniation was associated with a larger defect in the anterior abdominal wall at the stomal site and was more common lateral to the stoma. No association was shown between herniation and the underlying disease process, or to the site of the stoma relative to the rectus abdominis muscle. Demonstration of a hernia by clinical examination or CT was important in clinical management decisions. CT is recommended in patients with stoma-related symptoms or unexplained abdominal symptoms following ileostomy formation when a para-stomal hernia is suspected, but clinical examination is negative.

Radiography of the paranasal sinuses--one or three views?

A prospective study of 100 adult patients undergoing paranasal sinus radiography was performed. Two experienced radiologists independently assessed a single occipitomental view and, at a later date, the traditional three projections, i.e. occipitomental, occipitofrontal and lateral. There was 99% intra-observer agreement between the diagnosis on a single projection compared with all three films. In five cases, the frontal sinuses were difficult to assess mainly due to poor radiography, and in defined circumstances additional views may be required occasionally. We conclude that with greater attention to radiographic technique the occipitomental view alone is sufficient for diagnostic purposes.

Emergency angioplasty of the left main coronary artery.

During urgent cardiac catheterization total occlusion of a severe left main coronary artery stenosis occurred, leading to profound cardiogenic shock. The patient survived, after prompt left main coronary angioplasty was performed, followed by emergency coronary bypass surgery.

The hemipelvis: an unusual site of osteonecrosis. A report of two cases.

Osteonecrosis or aseptic necrosis is well-recognised in certain sites. We report two patients, both with predisposing factors, who developed avascular necrosis of the hemipelvis which was bilateral in one case. In each patient the diagnosis was not suspected clinically. In the initial phase, bone scintigraphy showed diminished uptake in the hemipelvis when plain radiographs were normal. Follow-up scans showed evidence of revascularisation. This is an unusual site for osteonecrosis, though there appears to be an underlying anatomical basis for its occurrence.

Cardiac haemangioma associated with a facial port-wine stain and recurrent atrial tachycardia.

We report an unusual case of a 44-year-old lady with a facial port-wine stain and a life-long history of atrial tachycardia who was found to have a large haemangioma lying posterior to the heart supplied by both the right and left coronary arteries. The facial port-wine stain was felt to be a cutaneous marker of the cardiac neoplasm.

Chronic proximal aortic dissection presenting as tamponade after 16 years.

A patient presented with tamponade and haemopericardium 16 years after experiencing sudden severe chest pain associated with enlargement of the proximal aorta. Investigations revealed a proximal aortic dissection (DeBakey type II) with extensive laminar and partially calcified thrombus within its false lumen and a large pericardial effusion, which together resulted in a cardiothoracic ratio of 100%. Long term survival after medical treatment of proximal aortic dissection, with such late progression to tamponade, has not been reported before.

Gastric emptying and small bowel transit times in volunteers after intravenous morphine and nalbuphine.

Gastric emptying half-times and small intestinal transit times were measured in a double-blind crossover study of 17 volunteers who received an intravenous injection of nalbuphine (5 or 10 mg), morphine (5 mg) or placebo. Both times were monitored using a gamma camera after a radioactive test meal and gastric emptying half-time was calculated. Small intestinal transit time was measured by the appearance of radioactivity in the caecum and also of hydrogen in end tidal air. Gastric emptying was prolonged over placebo by nalbuphine 10 mg, which had more effect than nalbuphine 5 mg or morphine 5 mg; morphine 5 mg had less effect than nalbuphine 5 mg. Small intestinal transit time was prolonged over placebo by nalbuphine 10 mg more than by nalbuphine 5 mg or morphine 5 mg, which had approximately equal effects. In these respects, the potency ratio of nalbuphine appears roughly equivalent to morphine. Small intestinal transit times measured by end tidal hydrogen concentration and gamma camera showed close agreement.