Calibration of a 0.08 Tesla magnetic resonance imager for in vivo T1 and T2 measurement.
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Biomedical subjects
Publications and source records attributed to P Armstrong.
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In an attempt to identify the number and characteristics of inappropriate reattendances at out-patient clinics, clinic doctors and patients in two specialties throughout a health district were given a questionnaire to complete on every patient attendance over one week. Four hundred and fifty-two patients were seen, and 293 were asked to reattend: in some 80 of the latter cases the clinic doctor felt that the GP could nevertheless manage the problem. These 'inappropriate' invitations to reattend were more likely to be given by junior hospital staff to long-standing patients of the clinic attending for monitoring purposes. The patients involved in these 'inappropriate' requests to reattend also tended to think that their GP could manage the problem. It is concluded that discharge policy needs to be made more explicit and training for juniors organized if out-patient resources are to be used most efficiently.
Papers in the review period have investigated the reasons why radiologists frequently overlook early lung cancers and have demonstrated that the rate at which radiologists falsely categorize a solitary pulmonary nodule as benign, through the use of commercially available CT phantom densitometry is higher than was previously believed. Attempts have also been made to find CT characteristics other than density that may help to distinguish benign from malignant nodules. A number of articles have addressed methods of improving the yield and reducing the pneumothorax rate following needle biopsy of pulmonary nodules. The major role of the radiologist when evaluating patients with known or probable lung cancer is to stage the tumor. The recent literature describing the accuracy of CT and MR imaging in staging lung cancer is also reviewed.
The principle of treatment of congenital pseudoarthrosis of the tibia (CPT) with the Ilizarov method corrects all angular deformity and maximizes the cross-sectional area of union of the pseudoarthrosis. Fifteen patients with a total of 16 CPT were treated using the Ilizarov apparatus. Various forces were used to treat the pseudoarthrosis site including compression, distraction, open reduction, resection and shortening, resection and bone transport, and invagination of one end in the other. Lengthening was performed in 12 of the 16. Deformity was corrected in all cases. The union rate was 94% with one treatment and 100% with two treatments. There were five refractures, three early and two late. Previous pin sites, residual angular deformity, and natural history were considered predisposing factors for refractures. One patient refractured twice but remained ununited. Fifteen remained united, with a mean follow-up period of four years (range, two to seven). There were two residual deformities, one in the regenerate and one at the level of the CPT.
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OBJECTIVE: To assess the effect of pressure from patients on patterns of general practitioners' outpatient referrals. DESIGN: Survey of general practitioners' referrals to hospital outpatient departments during one week. SETTING: One health district. SUBJECTS: All (160) general practitioners in the health district. MAIN OUTCOME MEASURES: Specialty of the referral, the reason for it, and its status (NHS or private) and the general practitioner's assessment of the degree of pressure exerted by the patient for the referral (much, little, or none). RESULTS: 122 (76%) general practitioners completed the survey. Younger general practitioners (aged less than or equal to 45) and those qualifying in the United Kingdom and Republic of Ireland reported greater pressure from patients to refer (p less than 0.03, p less than 0.001 respectively). Pressure was also greater for patients referred privately (p less than 0.001), for those referred for reassurance (p less than 0.05), and for those referred to clinics in psychiatry, rheumatology, dermatology, and orthopaedics. General practitioners with a higher referral rate (with total consultations in the week as the denominator) were more likely to report pressure (p less than 0.01). CONCLUSIONS: The pressure from patients to refer reported by general practitioners is related both to general practitioners' characteristics and to the nature of the referral. Pressure to refer seems to explain some of the variation in referral rates among general practitioners.
In October 1989, the Canadian Cardiovascular Society announced a program to achieve consensus on important issues in the care of patients with cardiovascular disease. This report on the management of the postmyocardial infarction patient represents the first in a series of these consensus conferences. The process for establishing consensus recommendations involved several steps. A primary panel of 11 experts from various fields was selected to review the available clinical evidence and to make a list of recommendations about management decisions in the postmyocardial infarction period. The initial report was distributed to a secondary panel of 16 reviewers* representing allied health care constituencies from across Canada. On the basis of the critical reviews and feedback from these reviewers, a revised report was distributed to all members (over 800) of the Canadian Cardiovascular Society for further review and feedback. This iterative approach resulted in a penultimate report that was presented at a plenary session of the annual scientific meeting of the Canadian Cardiovascular Society on Oct. 18, 1990, in Halifax, NS. On the basis of discussion and feedback from this symposium, the consensus review was completed.
We have investigated the possible toxicity of nitrous oxide on vitamin B12 and its sequelae upon folic acid metabolism using the urine formiminoglutamic acid excretion test, an index of the functional state of folate metabolism. Ten control subjects not exposed to nitrous oxide and five patients receiving limb surgery under local anaesthesia excreted normal amounts of formiminoglutamic acid in urine for 6 days. Fifty patients received nitrous oxide anaesthesia for similar surgery and, of these, 22 had a dose-dependent increase in excretion on the first 2 days after operation. There were large individual variations. Exposure to 70% nitrous oxide appeared to cause abnormal metabolism of folate when exposure was greater than 90 min. Ten anaesthetists demonstrated normal excretion of formiminoglutamic acid; their exposure to nitrous oxide was typical of that in other studies of theatre environmental pollution.
Fifteen volunteers underwent intravenous regional anaesthesia on two occasions using 40 ml 0.5% prilocaine, to which had been added either 2 ml 0.9% saline or 0.1 mg fentanyl (resultant concentration 2.5 micrograms/ml). There was no difference in the rate of onset of blockade of cold sensation from an ethyl chloride spray, or to sharp and touch pinprick sensation in either group. There was an increase in the incidence of nausea after tourniquet release in the fentanyl group. It is concluded that the addition of fentanyl 2.5 micrograms/ml to prilocaine 0.5% confers no benefit in intravenous regional anaesthesia.
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To evaluate the use of selective decontamination of the digestive tract (SDD) (polymyxin, amphotericin, tobramycin, and intravenous cefotaxime) in a mixed intensive care unit, we performed a stratified, randomized, prospective study. The 331 patients were recruited over an 18-month period, with 256 patients remaining more than 48 hours. Stratification by acute physiology and chronic health evaluation (APACHE II) preceded randomization to control (standard antibiotic therapy) or treatment (SDD) groups. Nosocomial infection was significantly reduced in the SDD group (16.7%; 21 of 126 patients) compared with the control group (30.8%; 40 of 130 patients; p = 0.008). No difference was found in overall mortality rate or length of stay between the two groups. Those patients with admission APACHE II scores 10 to 19 demonstrated the most significant reduction in nosocomial infection (23 of 70 control vs 13 of 76 SDD; p = 0.03) and mortality (15 of 70 control vs 8 of 76 SDD; p = 0.07). Emergence of multiresistant microorganisms was not a clinical problem, but a definite change occurred in the ecology of environmental and colonizing bacteria. With the exception of cefotaxime, a reduction was noted in systemic antibiotic usage in the SDD group. We conclude that SDD is useful in selected patients in a mixed intensive care unit.
The role of radiology in the initial detection and diagnosis of primary lung cancer is well established. Recent advances in the detection of lung cancer stem from research into the visual search patterns used by a radiologist when reading a chest radiograph. Computer feedback of "visual-dwell" positions can lead to an increase in true-positive detection of lung nodules and decrease the false-positive rate. Plain film radiography and CT continue as the mainstays for the characterization of lung nodules. New studies involving the use of conventional tomography to detect contrast enhancement of malignant lesions and the use of axial multiplanar reconstruction CT to demonstrate involvement of pulmonary veins by malignant lesions are detailed. Transbronchial and percutaneous transthoracic biopsy techniques are widely used to diagnose the nature of solitary pulmonary nodules. The dependent positioning of the biopsy site has been shown to decrease both the pneumothorax rate and the frequency of chest drain insertion, whereas the blood patch technique was shown not to affect the pneumothorax rate at all.
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In summary, chondrosarcoma arising in an osteochondroma is a difficult diagnosis to establish on radiological-morphological grounds, especially in low grade lesions. A patient with a painful, enlarging exostosis usually comes to require resection even in the absence of radiographic hallmarks of malignancy. Although many osteochondromas complicated by bursal formation will be resected for relief of symptoms, the identification of a reactive bursa surrounding an exostosis without grossly malignant features presages a benign course and will dramatically effect established preoperative plans.
One hundred and twenty unpremedicated patients undergoing gynaecological surgery were randomly allocated to one of three equal treatment groups to assess the effectiveness of ethyl chloride in producing instant skin anaesthesia to prevent the pain of venepuncture from a 20 G cannula. They received either no anaesthetic, 0.2 ml one per cent lidocaine plain intradermally or a ten-second spray of ethyl chloride at the cannulation site. Ethyl chloride produced skin anaesthesia that significantly reduced the pain of venepuncture. However, it was not as effective as intradermal lidocaine. It had no effect on vein visualisation or ease of cannulation. Ethyl chloride can be recommended as a method of producing instant skin anaesthesia.
Numerous pulmonary metastases entirely confined to one lobe are rare. A case is presented in which numerous pulmonary metastases from renal cell carcinoma were initially confused radiologically with lobar pneumonia.
An empty 500-ml infusion bag was used as the cuff for a Lifestat 100 oscillotonometer. The systolic and mean blood pressures obtained in 40 subjects were not significantly different from those measured with a standard cuff. The diastolic pressure was unrelated between the two cuffs. The empty bag is a cheap and hygienic option in patients who present a high infection risk.