Carbon dioxide methods of double contrast barium enemas

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CLINICAL RADIOLOGY

radiologist is ideally equxpped to help in choosing appropriate investigtions. Furthermore, the performance of both radiologxcal and endoscopic examinations within the same department tends to improve communication between investigators leading to better standards and a more honest assessment of the strengths and limitations of both types of examination. The ability of GPs and non-endoscoping clinicians to refer directly to an endoscopy service whether clinically or radiologically based or of a multidisciplinary type is highly cost and time effective when compared with the more cumbersome method of prior outpatient referral to a gastroenterology clinic. Clearly some patients will need to take this longer route but in very many cases the need for and appropriateness of endoscopy is unquestioned. We have experience of running such a service, radiologically led but multidisclplinary in make up, for a period of 13 years in Plymouth and are firmly of the opinion that it is well worth the cost in terms of extra radiological manpower requxred. D. E. BECKLY J H. HALL

Radlodlagnostlc Department Plymouth General Hospital Freedom Fields Plymouth

SIR Dr Bartram is right; there is no inherent reason why radiologists should not perform endoscopy. However, he argues against the increasing involvement of radiologists in routine endoscopy on the basis that this would take time and divert radiologists from other facets of radiology. This may indeed be true but surely the same argument could be levelled against time consuming radiological involvement in many techniques which lie on the frontiers between radiological, surgical and medical practice. That endoscopy is a method of imaging the gastrointestinal tract is undeniable although whether it is an imaging technique in the conventional radiological sense is debatable. However, it would be a shame if a semantic point was used to obscure the real advantages that closer radiological involvement in gastrointestinal endoscopy could bring. Perhaps we should ask 'are there good reasons why the radiologist should perform endoscopy'. Endoscopic practice is changing. No longer can an endoscopist confine himself to examining his own patients. He now needs to offer an endoscopy service to his hospital and probably also to his local general practitioners. There are, at present, not sufficient gastroenterologist endoscopists to provide such a service and the deficit is currently made up by many general practitioner clinical assistants. The radiologist is familiar with the concept of providing such a service and surely has a contribution to make. The closer clinical contact that participation in endoscopy brings is not just satisfying, it is of positive benefit to patient and radiologist and hopefully also to the physician and surgeon. The radiologist with endoscopic experience xs better able to audit the quality of his gastrointestinal investigations, be they endoscopic or double contrast and is also better able to select appropriate investigation. Dr Bartram accepts that radiologists who have an interest in ERCP, endoscopic ultrasonography or flexible sigmoidoscopy should have the opportunity to practise but if they do not also perform routine diagnostic examination how are they to gain experience and progress to the more advanced techniques and more importantly how are they to train others. There is much interest amongst radiologists in training who wish to acquire endoscopic skills and such training is at present difficult to obtain. The experienced radiologist-endoseopist should contribute to the endoscopy service, should maintain his own endoscopic skills and should train others. Good equipment is expensive and centrally based equipment would avoid fragmentation with its associated inefficiency. Video-endoscopy represents the endoscopy of the future. The video-endoscope is a piece of equipment which would be at home in most radiology departments. A digital image is produced which can be recorded photographically, on floppy disc or magnetic tape. Image processing of video-endoscopic images is developing. Sounds familiar? Given the already close links between endoscopy and other imaging techniques the future of the endoscopy department must lie within the expanded radiology department as does the future of much biliary and urological surgery. Is it any less appropriate for the radiologist to become more closely involved in endoscopy than it is for him to involve himself in these other previously non-radiological areas.

SIR I agree as to the right of radiologists with a particular interest m gastroenterology to perform endoscopy, and especially ERCP, but disagree as to the extent that such a service can be supplied by radiologists, given the other demands of the subject in gastroenterology. However, there is still common ground. Radiologists are trained to provide a technical diagnostic service directly involving patients, and their departments are organised to do so. What better situation for endoscopy than as an expanded sector of a radiology department9 Sharing changing facdlties, reception, nursing care, and screening equipment with ERCP, is a rational use o f resources. In this environment endoscopy could be easily undertaken as a multidisophnary venture between interested radiologists and clinicians. My challenge to these enthusiasts who have kindly written to me is simple; convince those bodies that can put your views into practice, notably the Brihsh Society of Endoscopy and our College. Cooperation between endoscopists and radiologists on a larger and more formally recognised scale will be of mutual benefit, but any sacrifice in our &agnostic services must be avoided. C. I. B A R T R A M

Department of Radiology St Mark's Hospital City Road London ECIV 2PS

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D. F. M A R T I N

Gastroenterology Unit University Hospital of South Manchester Nell Lane West Didsbury Manchester M20 8LR

CARBON DIOXIDE M E T H O D S OF DOUBLE CONTRAST BARIUM ENEMAS SIR Dr Bartram is to be congratulated for simplifying the use of carbon dioxide for double contrast barium enema examinations by using a pressure-reducing valve and pin for filling the enema bag with carbon dioxide from a tank (Bartram, 1989). In 1963 we reported a similar technique introducing carbon dioxide, via a plastic tubing, directly into the tubing of the enema bag containing the barium suspension. We also used a regulator which monitored the carbon dioxide flow from the tank (Pochaczevsky and Sherman, 1963). Dr Bartram correctly quotes our most recent article describing a second bag attached to the enema kit in which carbon dioxide is generated from an effervescent powder (Pochaczevsky, 1987). An advantage of the second bag is better control of gas insufflation since its tubing contains no barium which must be cleared before gas enters the colon. In the interest of completeness, I believe it is important to add that, in the same paper, we described an alternate method which dispenses with the use of both the carbon dioxide tank and a second bag by pouring the effervescent powder directly into the enema bag containing the liquid barium suspension. Dr Bartram's successful experience in his institution confirms the concept that carbon dioxide is preferable to air in reducing severe cramps or distension following double contrast examinations of the colon. -

R. POCHACZEVSKY

Department of Radiology Long Island Jewish Medical Center New Hyde Park, N Y 11042 USA

References Bartram, CI (1989). Technical note: a simple method for using carbon dioxide during double contrast barium enema. Clinical Radiology, 40, 318 Pochaczevsky, R and Sherman, RS (1963). A new technique for the roentgenologic examination of the colon. American Journal of Roentgenology, 89, 787-796. Pochaczevsky, R (1987). Double-contrast examination of the colon with carbon dioxide: the use o f effervescent powder. American Journal of Roentgenology, 149, 502-504. SIR I have long admired Dr Pochaczevsky's inventiveness and he has made a number o f useful contributions to the techniques of barium examinations. I am sure that the apparatus described in his two papers works well. My aim was to present the simplest and least expensive method. 1 appreciate the advantages of a second bag for the gas, but it does add to the expense. Using sufficient effervescent agent to generate 1-2 1 of gas would I imagine be more expensive than using bottled gas. I am also concerned that if proprietary agents designed for upper GI studies are used, then the antifoaming agents that these contain may have a very deleterious effect on coating. I must admit that I have not tried this, and

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CORRESPONDENCE may well do so as it could be a useful adjunct should one need more gas during the examination. The method I have described does not allow for this, as one has to cut the tube and insutttate with air from a bulb inflator. Perhaps we can therefore combine the techniques to advantage. C. I. B A R T R A M

Department of Radiology St Mark's Hospital City Road London ECIV 2PS

WHATS IN A NAME? SIR English Is a living language, a fact which is shown not only by the evolution o f the meaning of some words. Similarly, medicine as a whole and in every part is developing year by year. The use of the word 'radiology', defined as the 'study of radioactivity and radiation or their application to medicine', exemplifies those changes. For some 25 years after the discovery of ionising radiations and their introduction into medical practice the doctors interested came from many other specialties, and tended to be entitled 'Physician or Surgeon to the Electrology or X-ray Department'. During World War 1 the first radiologists appeared, together with the first examination, the Cambridge DMRE. It would be surprising if there were a ready possibihty of comparing the work of a radiologist then with that o f his counterpart today. In one's clinical lifetime since 1945 the two branches of radiology, radiodiagnosis and radiotherapy, have changed, in step with every other branch of medicine, but part passu so has the general understanding of what the words mean. The recent 40th anniversary of the NHS seems an appropriate occasion to review these changes. In both radiodiagnosis and radiotherapy the changes result from the development of existing techniques (e.g. apparatus, films and screens, intensifiers, fractionation), the introduction of new discoveries (computers, isotopes, ultrasound, cytotoxic drugs, magnetxc resonance) and changes in docotors' interests and attitudes (clinical trials, physicians with an interest, sub- or super-specialisation in radiology and in the rest of medicine). The rate of change has varied between individual practitioners and departments, often depending on the availability of material resource, the replacement o f a senior consultant by a young successor, and progress by other specialties in the same hospital. The College has variously encouraged changes in practice by educational meetings and publications, and has reacted to progress by updating its curricula and examinations. In addition, it has moved from a position of having an exit examination towards that of an entry examination, prior to in-depth pre-consultant experience. Over the years, both the College and individual members have made attempts to adopt a title thought to be more accurately descriptive of their practice, but it is interesting to note that other consultant colleagues in hospital, other Royal Colleges and government have all failed to accept the proposals. So we still work in X-ray or Radiology -

Departments or Radiotherapy Centres, and are listed in national statistics as radiologists or radiotherapists. To some extent those suggestions arose because it was thought that separately we work more closely with other specialists than with each other, but it is still true that radiotherapy depends critically in tumour assessment, and in monitoring the response to treatment on every available radiodiagnostic technique, while every such diagnostic technique has relied at least in its developmental phase on its application to patients with cancer. It is interesting to remember that radiotherapists used transverse body sections routinely in planning treatment for many years before the advent of computed tomography. Further, since radiology is now a very large specialty it is no longer uniform. In departments with several consultants it is natural that some should develop special interests, and therefore for a neuroradiologist to be increasingly unhappy in dealing with gastrointestinal problems, or indeed for a radiotherapist who spends most of his time in a lymphoma clinic to be happy in a gynaecological theatre. But similar comments are true o f surgery, medicine, anaesthesia and indeed of all specialties. The 'average' radiologist in 1989 would expect to meet in a week's work at least some of the applications of CT, isotope studies, ultrasound, digitisation or interventional radiology, while a radiotherapist would similarly deal with a linear accelerator, afterloading and multiple cytotoxic therapy. So I make a plea for all users of ionising radiations in medicine to remain united in our Royal College of Radiologists, as our important branches of medicine continue to develop, and avoid wasteful dissipation of energy in worrying about a change in our honourable name. W. M. ROSS

62 Archery Rise Durham City DH1 4LA

BRITISH STANDARDS SPECIFICATION FOR BALLOON DILATATION CATHETERS SIR Some of your readers may like to know that a draft specification for Balloon Dilatation Catheters has been prepared by the British Standards Institute. This draft is now available for public comment and can be obtained from the Sales Administration (Drafts), British Standards Institute, Lindford Wood, Milton Keynes, MK1 46LE. Apparently the cost for this is £8.00. Anyone wishing to comment on this draft specification can commumcate their comments directly to British Standards Institute. I represent the Royal College of Radiologists on the committee which developed this draft standard and I wdl also be happy to receive any comments from interested cardiologists and radiologists working in this field. -

G. H A R T N E L L

Brtstol Royal Hospztal for Sick Children St Michael's" Htll Bristol BS2 8BJ