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Contrast medium reactions
CORRESPONDENCE/BOOK REVIEWS We would like to clarify first that the patients received one contrast medium injection only, with a total iodine dose of 42.5 G m which is a widely accepted dose for abdominal CT scans. With hindsight it m a y be stated that the delayed C T scans did not alter the m a n a g e m e n t of m a n y of the patients. However, this was not known before the delayed images were obtained. At the time, the delayed images were considered to be indicated clinically and some did in fact show microabscesses not detected on the scans obtained early after contrast medium. It is not correct to state that the abscesses would presumably have been identified with ultrasound. On the contrary, it is recognized that enhanced C T is a more sensitive detector of renal abscesses than is ultrasound [1]. L. D A L L A - P A L M A
Universita Delgi Studi Di Trieste Instituti Di Radiologica Ospedale Di Cattinava Italy
1 Soulen MC, F i s h m a n EK, G o l d m a n SM, Gatewood OMB. Bacterial Renal Infection: Role o f CT. Radiology, 1989; 171:703-707.
administration of adrenaline might be fatal, that its benefits outweigh its risks in a developing adverse reaction, and that radiologists should consequently be ready to administer it before the crash team arrives. The next update will be prepared with these points in mind. The result of more thought and more input will surely make it even more authoritative in the eyes o f radiologists to whom it is distributed. (3) Finally, and more generally, I would say this. I am not, I should make clear, a great admirer of the postal survey. As Professor Sherwood knows, I am a true and steadfast worshipper at the shrine of science. However, at least we can say that 'research' of the kind embodied by the surveys, gets the registrars planning, executing, analysing and writing something. I would prefer that they were developing more basic research skills in proper academic departments worthy of the name - measuring endothelin levels in contrast agent associated nephrotoxicity or exploring the role o f nitric oxide in the pathophysiology of anaphylactoid reactions, say but, sadly, we have allowed, by our neglect, academic radiology to decline from a not very high peak and we continue to set our sights low. Come on Tom, stop counting the angels on the points o f your specific gravity cones and tackle the big issues. W h y did academic radiology not flourish and is it too late to do anything about it? P. D A W S O N
CONTRAST MEDIUM REACTIONS S m - It is not m y habit to intrude in private grief or elbow m y way into others' arguments but in the recent exchanges between Sherwood, Sa~ller et at. and Brown [1] I felt that m y colleague, Paul Sidhu, and I were spectres at the feast: hovering but unnamed. Perhaps it was felt that if n a m e d we might materialize and spoil the party? I think Sadler et al. and Brown have more than satisfactorily disposed o f Professor Sherwood's criticism, but m a y I make the following comments? (1) Professor Sherwood makes reference to specific gravity cones. I carried out m y own survey with an interesting and illuminating result. I asked twenty randomly selected radiologists 'what is a specific gravity cone?' Twelve made some attempt to reply. O f these only five had a reasonably clear understanding; the other seven tied themselves up in a variety of knots with their vague notions. The remaining eight refused to treat the question seriously and would, in effect, not answer. The point of this is not to poke fun at the choice of such an esoteric reference standard, tempting as that is, but to make the altogether more serious point that these results are m u c h the same as those of Sadler et al. [2] and Brown [3], i.e. ~ 6 0 % responded but some got it wrong, or did not know as m u c h as they thought, and about 40% would not respond. I am sure most nonresponders were hiding their ignorance. I cannot prove that, but never underestimate the h u n c h in science. I suspect we can be fairly sure that the 40% or so non-responders in the published surveys were either simply too lazy, too uninterested or afraid to show their ignorance. I feel it unlikely they were simply hiding their brilliant lights under bushels. The surveys in any case did succeed, when all is said and done, in revealing a situation of serious ignorance and confusion in an important area. One assumes from his evident distaste for surveys that Professor Sherwood would be a nonresponder; his discussion of adrenaline doses certainly put him in the cause for alarm group. Perhaps most worrying of all is that one o f our Professors should so fumble his literature search! (2) As regards the College Guidelines, Professor Sherwood uses the term 'self-assigned authority'. Whatever authority is assigned to such guidelines is assigned by members of the profession and is so assigned on the basis o f an understanding that appropriate experts have been consulted, that several drafts have been kicked around by yet other experts, and that the committees and officers o f the College are not entirely stupid. Dr Sidhu and I prepared a draft, taking a good deal o f advice, and that is why were are thanked. That was only the beginning, but not a bad one, of an authority building process. Arguably such a College document should have more authority than 'holy writ' since you can trace its provenance, check its sources and inspect the credentials of its authors! Nevertheless, even the most authoritative document is not above criticism and one levelled at this one does indeed concern adrenaline. Because adrenaline is a drug not without its dangers, however administered, we were concerned it might be given too readily to treat urticaria or a case of transient light-headedness. That is why, with the support of anaesthetic advice, we suggested its use by the crash team. A n u m b e r of people have suggested that to delay 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 880-882.
881
Department o f Radiology Hammersmith Hospital London UK
References 1 Sherwood T: Sadler D J, Parrish F, Coulthard A: Brown P W G . Contrast medium reactions (letters). Clinical Radiology 1995;50:506. 2 Sadler D J, Parrish F, Coulthard A. Intravenous contrast media reactions: how do radiologists react? Clinical Radiology 1994;49: 879-882. 3 Brown PWG. Can radiologists manage reactions to intravascular contrast media? Clinical Radiology 1994;49:906.
D E M O N S T R A T I O N OF P O P L I T E A L ARTERY E N T R A P M E N T ON LEG MUSCLE SCINTIGRAPHY STR - We feel compelled to make certain comments on the recent paper by Set et al. [1]. (1) The first sentence of the abstract 'Popliteal artery entrapment is difficult to diagnose even at surgery' is complete nonsense for three reasons: (a) This statement is completely unsupported by any reference; (b) Nobody would undertake surgery to diagnose a Popliteal entrapment syndrome, the diagnosis should already have been confirmed by other means before surgery is considered; (c) Popliteal entrapment syndrome is obvious at surgery. (2) The third sentence in the abstract 'There is no sensitive method for the evaluation of this condition' is also totally false. Duplex Ultrasound is an extremely good method for screening any potential cases [2,3]. It is totally non-invasive. Following this a definitive diagnosis can be made with an arteriogram [3]. (3) There are now considered to be 300 [4] cases in the world literature, not the 150 slated. (4) The reference to ultrasonography is 18 years old. Since 1977 the capabilities of ultrasound machines and in particular the development of Duplex scanners has enabled these techniques to be m u c h more reliable and useful. (5) To consider this technique (MIBI) to be non-invasive when it requires iv cannulation and two separate doses of radiation is a little absurd, particularly when compared with ultrasound. (6) Case reports 2 and 3 both state that ultrasound (colour flow Doppler in case 2 and walk test in case 3) and conventional angiography are adequate techniques for diagnosing this condition. M. J. A L L E N M. R. BARNES P. R. F. BELL*
Department o f Sports Medicine Leicester General Hospital Leicester, UK
* University Department o f Surgery, Leicester Royal Infirmary References 1 Set PAK, Miles K A , Jenner JR, Morris, E. Demonstration of
Universita Delgi Studi Di Trieste Instituti Di Radiologica Ospedale Di Cattinava Italy
1 Soulen MC, F i s h m a n EK, G o l d m a n SM, Gatewood OMB. Bacterial Renal Infection: Role o f CT. Radiology, 1989; 171:703-707.
administration of adrenaline might be fatal, that its benefits outweigh its risks in a developing adverse reaction, and that radiologists should consequently be ready to administer it before the crash team arrives. The next update will be prepared with these points in mind. The result of more thought and more input will surely make it even more authoritative in the eyes o f radiologists to whom it is distributed. (3) Finally, and more generally, I would say this. I am not, I should make clear, a great admirer of the postal survey. As Professor Sherwood knows, I am a true and steadfast worshipper at the shrine of science. However, at least we can say that 'research' of the kind embodied by the surveys, gets the registrars planning, executing, analysing and writing something. I would prefer that they were developing more basic research skills in proper academic departments worthy of the name - measuring endothelin levels in contrast agent associated nephrotoxicity or exploring the role o f nitric oxide in the pathophysiology of anaphylactoid reactions, say but, sadly, we have allowed, by our neglect, academic radiology to decline from a not very high peak and we continue to set our sights low. Come on Tom, stop counting the angels on the points o f your specific gravity cones and tackle the big issues. W h y did academic radiology not flourish and is it too late to do anything about it? P. D A W S O N
CONTRAST MEDIUM REACTIONS S m - It is not m y habit to intrude in private grief or elbow m y way into others' arguments but in the recent exchanges between Sherwood, Sa~ller et at. and Brown [1] I felt that m y colleague, Paul Sidhu, and I were spectres at the feast: hovering but unnamed. Perhaps it was felt that if n a m e d we might materialize and spoil the party? I think Sadler et al. and Brown have more than satisfactorily disposed o f Professor Sherwood's criticism, but m a y I make the following comments? (1) Professor Sherwood makes reference to specific gravity cones. I carried out m y own survey with an interesting and illuminating result. I asked twenty randomly selected radiologists 'what is a specific gravity cone?' Twelve made some attempt to reply. O f these only five had a reasonably clear understanding; the other seven tied themselves up in a variety of knots with their vague notions. The remaining eight refused to treat the question seriously and would, in effect, not answer. The point of this is not to poke fun at the choice of such an esoteric reference standard, tempting as that is, but to make the altogether more serious point that these results are m u c h the same as those of Sadler et al. [2] and Brown [3], i.e. ~ 6 0 % responded but some got it wrong, or did not know as m u c h as they thought, and about 40% would not respond. I am sure most nonresponders were hiding their ignorance. I cannot prove that, but never underestimate the h u n c h in science. I suspect we can be fairly sure that the 40% or so non-responders in the published surveys were either simply too lazy, too uninterested or afraid to show their ignorance. I feel it unlikely they were simply hiding their brilliant lights under bushels. The surveys in any case did succeed, when all is said and done, in revealing a situation of serious ignorance and confusion in an important area. One assumes from his evident distaste for surveys that Professor Sherwood would be a nonresponder; his discussion of adrenaline doses certainly put him in the cause for alarm group. Perhaps most worrying of all is that one o f our Professors should so fumble his literature search! (2) As regards the College Guidelines, Professor Sherwood uses the term 'self-assigned authority'. Whatever authority is assigned to such guidelines is assigned by members of the profession and is so assigned on the basis o f an understanding that appropriate experts have been consulted, that several drafts have been kicked around by yet other experts, and that the committees and officers o f the College are not entirely stupid. Dr Sidhu and I prepared a draft, taking a good deal o f advice, and that is why were are thanked. That was only the beginning, but not a bad one, of an authority building process. Arguably such a College document should have more authority than 'holy writ' since you can trace its provenance, check its sources and inspect the credentials of its authors! Nevertheless, even the most authoritative document is not above criticism and one levelled at this one does indeed concern adrenaline. Because adrenaline is a drug not without its dangers, however administered, we were concerned it might be given too readily to treat urticaria or a case of transient light-headedness. That is why, with the support of anaesthetic advice, we suggested its use by the crash team. A n u m b e r of people have suggested that to delay 9 1995 The Royal College of Radiologists, Clinical Radiology, 50, 880-882.
881
Department o f Radiology Hammersmith Hospital London UK
References 1 Sherwood T: Sadler D J, Parrish F, Coulthard A: Brown P W G . Contrast medium reactions (letters). Clinical Radiology 1995;50:506. 2 Sadler D J, Parrish F, Coulthard A. Intravenous contrast media reactions: how do radiologists react? Clinical Radiology 1994;49: 879-882. 3 Brown PWG. Can radiologists manage reactions to intravascular contrast media? Clinical Radiology 1994;49:906.
D E M O N S T R A T I O N OF P O P L I T E A L ARTERY E N T R A P M E N T ON LEG MUSCLE SCINTIGRAPHY STR - We feel compelled to make certain comments on the recent paper by Set et al. [1]. (1) The first sentence of the abstract 'Popliteal artery entrapment is difficult to diagnose even at surgery' is complete nonsense for three reasons: (a) This statement is completely unsupported by any reference; (b) Nobody would undertake surgery to diagnose a Popliteal entrapment syndrome, the diagnosis should already have been confirmed by other means before surgery is considered; (c) Popliteal entrapment syndrome is obvious at surgery. (2) The third sentence in the abstract 'There is no sensitive method for the evaluation of this condition' is also totally false. Duplex Ultrasound is an extremely good method for screening any potential cases [2,3]. It is totally non-invasive. Following this a definitive diagnosis can be made with an arteriogram [3]. (3) There are now considered to be 300 [4] cases in the world literature, not the 150 slated. (4) The reference to ultrasonography is 18 years old. Since 1977 the capabilities of ultrasound machines and in particular the development of Duplex scanners has enabled these techniques to be m u c h more reliable and useful. (5) To consider this technique (MIBI) to be non-invasive when it requires iv cannulation and two separate doses of radiation is a little absurd, particularly when compared with ultrasound. (6) Case reports 2 and 3 both state that ultrasound (colour flow Doppler in case 2 and walk test in case 3) and conventional angiography are adequate techniques for diagnosing this condition. M. J. A L L E N M. R. BARNES P. R. F. BELL*
Department o f Sports Medicine Leicester General Hospital Leicester, UK
* University Department o f Surgery, Leicester Royal Infirmary References 1 Set PAK, Miles K A , Jenner JR, Morris, E. Demonstration of