The process of evidence-based practice in radiology: an introduction

EBP can be used by radiologists to assess imaging modalities using the recognized “Ask, Search, Appraise, Apply, and Evaluate” steps. The technology assessment framework is also a useful tool to stratify an imaging modality according to its technical and diagnostic performance. It can also be used to assess its therapeutic and diagnostic impact as part of the “Evaluate” step of EBP. We have described how these two processes can be combined and used in a synergistic way. While its format may appear unorthodox compared to conventional research methodology (i.e., aims, methods, results, and conclusion), it is a practical and readily interpreted way of bridging the gap between EBP and primary research. An example of its application entitled “Combining ‘Evidence-Based Practice’ and ‘Technology Assessment’ Methods to Develop Departmental Imaging Protocols: Should FDG PET Be Routinely Used in the Preoperative Assessment of Patients With Colorectal Liver Metastases?” is published in this issue. Further details of this process and its potential impact on technology assessment, education, ethics, and radiology literature has been considered in a recent Radiology special series (11).     

Shuttle walking test: a new approach for evaluating patients with pacemakers.

OBJECTIVE: To validate an incremental field walking test, the shuttle walking test, as a means of assessing pacing modes and to aid programming of rate responsive pacemakers. DESIGN: Three separate groups of patients were recruited. Reproducibility (n = 10) of the shuttle walking test was assessed by performing three consecutive tests. Comparison of the shuttle walking test with a 10 min walk was assessed in 20 patients. In the third group (n = 10) patients with rate responsive pacemakers were programmed to either VVI fixed rate 70 beats/min or VVIR with the optimal rate response to show the discriminative value of the test. SETTING: Pacing clinic in a regional cardiothoracic centre. PATIENTS: 30 patients with chronotropic competence and dual chamber pacemakers with varying functional capacity and 10 patients with rate responsive pacemakers. INTERVENTIONS: Continuous haemodynamic monitoring was obtained using an ambulatory nuclear monitor, the Capintec VEST. Two exercise tests either shuttle walking test or 10 min corridor walk. The shuttle walk is an incremental walking test conducted on a 10 m course where the walking speed is dictated by bleeps on an audio cassette. RESULTS: Reproducibility was demonstrated over three consecutive tests with mean (1 SD) exercise times of 7.6 (1.7) min, 7.7 (1.6), and 7.7 (1.7) min. During the shuttle walk the test patients walked for a mean of 8.3 (1.2) min producing peak relative cardiac outputs of 78 (21) end diastolic volume/min compared with 64.9 (17) end diastolic volume/min for the 10 min walk (P < 0.001); peak heart rates were 118 and 104 beats/min (P < 0.03) respectively. In the third group relative peak cardiac output was significantly greater in VVIR (70 (24) v VVI 52 (15) end diastolic volume/min) (P < 0.009) as were exercise times (VVIR 8.8 (1.3) min v VVI 8.1 (1.3) min) (P < 0.003). CONCLUSIONS: The shuttle walk is an easy test to administer, requiring little equipment. It produces a symptom limited maximal performance and will be a useful aid to pacemaker programming as it is reproducible and able to show differences in exercise capacity between pacing modes.     

A Predictive Model of Suitability for Minimally Invasive Parathyroid Surgery in the Treatment of Primary Hyperthyroidism

Background  

Improved preoperative localizing studies have facilitated minimally invasive approaches in the treatment of primary hyperparathyroidism (PHPT). Success depends on the ability to reliably select patients who have PHPT due to single-gland disease. We propose a model encompassing preoperative clinical, biochemical, and imaging studies to predict a patient’s suitability for minimally invasive surgery.     

Patterns of coronary artery disease in post-infarction ventricular septal rupture

Cardiac angiography was reviewed in 91 patients with post-infarction ventricular septal rupture. The results were compared with those of 123 stable survivors who had a positive submaximal exercise test early after infarction. Anterior infarction and occlusion of the infarct vessel were more common in those with ventricular septal rupture than in the comparison group. In the group with ventricular septal rupture there was more left ventricular damage, with aneurysm formation in two thirds, and coronary angiography showed more single than triple vessel disease. In the comparison group there was more triple vessel disease than single vessel disease. Angiographically demonstrable collaterals to the infarct territory were not seen or only very faintly seen in 82% of those with septal rupture. Well developed collaterals were seen in two thirds of the comparison group. These patterns of coronary disease suggest that ventricular septal rupture is more likely in patients with coronary occlusion and little or no collateral support to the infarct territory.     

Infective endocarditis: incidence and mortality in the North East Thames Region

A survey of infective endocarditis in the North East Thames Regional Health Authority was carried out over a period of 30 months from 1982 to 1984. The incidence, clinical characteristics, and in-hospital mortality were studied. Important causes of endocarditis were dental treatment, the presence of dental disease, drug abuse, and cytoscopy. The omission or incorrect administration of antibiotic prophylaxis in patients with valve disease was noted, but failure of correctly prescribed antibiotic prophylaxis was not recorded. Adverse prognostic features were increased age, prosthetic valve infection, Gram negative or staphylococcal infections, and aortic valve involvement. In contrast, mortality was lower in patients with mitral valve prolapse, ventricular septal defect, and streptococcus viridans infection. Deaths were usually attributable to irreversible complications present at the time of diagnosis. Vegetations were detected on the echocardiogram in half of those studied and mortality was higher in those with vegetations than without. Operation for native valve infection was associated with a low mortality and it is likely that the overall mortality for infective endocarditis has been improved by surgical intervention.     

Recurrent syncope due to complete atrioventricular block,a rare presenting symptom of otherwise silent coronary artery disease: Successful treatment by PTCA

A patient presented with recurrent syncope and episodes of AV block preceded by asymptomatic ST segment elevation on ambulatory monitoring. Coronary angiography revealed a severe stenosis in the midsegment of the right coronary artery (RCA). Successful PTCA and stent insertion abolished further episodes of syncope. Cathet. Cardiovasc. Diagn. 42:216–218, 1997. © 1997 Wiley-Liss, Inc.