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Non-ionic contrast media: Do they cause renal damage?
386
ABSTRACTS
PATIENTS PREFER X-RAYS E. M c N A L L Y , G. DE LACEY, T. W E L C H and P. L O V E L L
Northwick Park Hospital, London
N O N - I O N I C C O N T R A S T MEDIA: D O T H E Y C A U S E RENAL DAMAGE? J. V. H U N T E R and P. N. K I N D
National Hospital for Neurology and Neurosurgery, London Seven hundred and ninety-eight patients who were not referred for radiography following a head or ankle injury were sent a questionnaire. Fifty-four per cent of the responders had expected an X-ray examination (Group 1). I m p o r t a n t differences are shown between G r o u p 1 patients and those who did not expect radiography (Group 2). These included: a higher level of disappointment (65% vs 0%), critical comments (84% vs 16%) and, following head injury, a longer mean recovery time (16 days vs 4 days). But there were very large differences in duration between age groups. F o r those in their teens s y m p t o m duration was four times longer for G r o u p 1 (20 days vs 5 days). This could well have important educational implications. Initial analysis suggests that the overall severity of head injury was no different between the two groups, and follow up has shown that no important abnormality has been missed by excluding radiography. These results have implications for all casualty departments. However, the implications m a y be particularly relevant to those who introduce guidelines which subsequently produce a reduction in X-ray examinations. Strategies (mainly to improve communication skills) which might reduce the overall level of patient dissatisfaction are obviously necessary, and some will be proposed.
AUDIT OF AN O P E N A C C E S S N O N - S C R E E N I N G MAMMOGRAPHY POLICY J. J. C U R T I N and M. A. S A M P S O N
Northwick Park Hospital, London There is continuing controversy about the value of m a m m o g r a p h i c screening in asymptomatic women. In particular the low detection rate has been criticized. At Northwick Park Hospital there is an open access policy for both General Practitioner and Breast Clinic referrals for clinically indicated, non-screening m a m m o g r a m s . This study is designed to audit the resultant abnormality yield. Three-hundred and fifty-two consecutive m a m m o g r a m s have been reviewed. All were new referrals. Two hundred and two were from General Practice and 150 from the Consultant-led Breast Clinic. Twenty per cent of cases from the Breast Clinic were reported as showing m a m m o g r a p h i c abnormalities requiring either biopsy or close follow-up. By contrast only 2% of cases from General Practice showed such abnormalities. We conclude that the yield from apparently clinically indicated m a m m o g r a m s referred from General Pi'actice is no higher than in the unselected screening programme. The reasons for and possible implications of these findings are discussed.
B A R I U M ENEMA: A U D I T OF T H E U S E AND U S E F U L N E S S OF AN O P E N ACCESS P O L I C Y B. J. M c K E O W N and M. A. S A M P S O N
Increasing use of non-ionic contrast media for routine imaging of the transplanted kidney has stimulated concern about the potential nephro. toxicity of these media. We report the results of a prospective study to assess possible nephrotoxicity in renal transplant patients. Levels of urinary enzyme activity (AAP, G G T and N A G ) were Used as markers of renal damage. These enzymes were measured before, immediately after and up to 72 hours following injection of non-ionic contrast in two groups of patients undergoing intravenous angiography. There were 26 patients with a renal transplant and 10 controls with normal renal function. All patients showed a transient rise in the levels of urinary enzyme activity, which peaked within 24 h and returned to pre-investigation levels within 72 hours. In the transplanted group the baseline levels of the three marker enzymes was higher and the response greater in magnitude following contrast injection. Nevertheless, the duration of the response was the same as in the control group, with all patients returning to their baseline levels of enzyme activity. F r o m these data it is concluded that whilst a transplanted kidney is more sensitive to the effects of non-ionic contrast than a native kidney, its potential for recovery is unimpaired. ABBREVIATING T H E I N D I V I D U A L I Z E D I V U - IS IT WORTHWHILE? D. N A G , M. B R I L E Y and E. W. L. F L E T C H E R
John Radcliffe Hospital, Oxford Intravenous urography constitutes a significant part of the workload of radiology departments. The standard I V U m a y consist of seven or more radiographs. We performed a pilot prospective study to assess whether the n u m b e r of radiographs taken routinely during IVUs could be reduced. Our study comprised 50 consecutive adults attending for an IVU. All patients had a 'standard IVU' under the supervision of a radiologist who prospectively sought selected radiographs. A provisional report was made on the abbreviated series and independently assessed by a second radiologist. Finally, radiographs from the 'standard series', not initially seen, were checked for additional diagnostic information. The abbreviated IVU consisted o f 5.5 radiographs (mean): in 30 (60%) cases five or less radiographs constituted a diagnostic IVU. The immediate radiograph (nephrogram) could be omitted in 42 (84%) and the compression view in 27 (54%). The post-voiding view, indications for which were agreed with our urologists was required in 28 (56%). This approach allows reduction of the effective dose equivalent (EDE) by as m u c h as 50% to 2.8 mSv per examination with additional financial benefits. We present the results of a questionnaire sent to 30 consultant radiologists seeking their vie';vs on IVU protocols. M A G N E T I C R E S O N A N C E I M A G I N G - A D I A G N O S T I C TOOL TO DIFFERENTIATE LYMPHOEDEMA, PHLEBOEDEMA AND L I P O E D E M A O F THE LOWER E X T R E M I T Y K. D. H A G S P I E L , ST. D U E W E L L , M. M c P H I L L I P S , E. FRICK, A. B O L L I N G E R and G. K. YON S C H U L T H E S S
University Hospital Ziirich, Zi~rieh, Switzerland
Northwick Park Hospital, London The barium enema is a commonly requested diagnostic procedure in hospital and general practice. The policy at Northwick Park Hospital is open access for General Practitioners. This study is designed to audit this policy with respect to diagnostic yield. In addition, we investigated the usefulness of a negative report in general practice, and the effect upon referral patterns. One thousand and fifty six referrals for barium enema were studied. GP requests constituted 24% with an average age of 61.7 years against 62.5 years for hospital referrals. A standard questionnaire was sent to General Practitioners receiving a normal report in order to assess the influence of the investigation on their decision to refer. The overall diagnostic yield was 28 % (GP cases 18 %, hospital cases 32%). The specific pick up rates with respect to clinical presentation are discussed. In a significant n u m b e r o f cases a normal report obviated the need for hospital referral. Our study has demonstrated that for a similar age distribution, General Practitioner referrals for barium enema examinations have a lower diagnostic yield for both benign and malignant disease than hospital referred cases. However, we emphasize the value of a normal examination in the reduction of referrals to hospital outpatient clinics.
The differential diagnosis of the swollen leg is usually based on clinical findings, but contrast examinations m a y be required, particularly to differentiate lymphoedema from venous oedema. To assess the usefulness of magnetic resonance imaging (MRI) we investigated 22 patients with lipoedema, lymphoedema or venous oedema on our 1.5 Tesla system. In each patient transaxial T1- and T2weighted spin echo (SE) sequences were obtained. After the application of G d - D O T A dynamic Gradient Echo scans were performed and the Tl-weighted SE scan was repeated. Lipoedema was easy to differentiate from the other two types of oedema because of its grossly and homogeneously enlarged subcuta" neous layer with no signal increase on T2-weighted sequences or after G d - D O T A . Patients with venous oedema showed diffuse collections of liquid-containing structures within the whole subcutis, whereas these were confined more or less to the layer between muscle and subcutis in lymphoedema. These structures were not found in patients with lipoedema and showed a marked signal increase in T2-weighted sequences and a slight one after G d - D O T A , somewhat more in lymphoedema than in venous oedema. Our results suggest that M R I is an appropriate tool for differentiation between different forms of oedema of the leg.
ABSTRACTS
PATIENTS PREFER X-RAYS E. M c N A L L Y , G. DE LACEY, T. W E L C H and P. L O V E L L
Northwick Park Hospital, London
N O N - I O N I C C O N T R A S T MEDIA: D O T H E Y C A U S E RENAL DAMAGE? J. V. H U N T E R and P. N. K I N D
National Hospital for Neurology and Neurosurgery, London Seven hundred and ninety-eight patients who were not referred for radiography following a head or ankle injury were sent a questionnaire. Fifty-four per cent of the responders had expected an X-ray examination (Group 1). I m p o r t a n t differences are shown between G r o u p 1 patients and those who did not expect radiography (Group 2). These included: a higher level of disappointment (65% vs 0%), critical comments (84% vs 16%) and, following head injury, a longer mean recovery time (16 days vs 4 days). But there were very large differences in duration between age groups. F o r those in their teens s y m p t o m duration was four times longer for G r o u p 1 (20 days vs 5 days). This could well have important educational implications. Initial analysis suggests that the overall severity of head injury was no different between the two groups, and follow up has shown that no important abnormality has been missed by excluding radiography. These results have implications for all casualty departments. However, the implications m a y be particularly relevant to those who introduce guidelines which subsequently produce a reduction in X-ray examinations. Strategies (mainly to improve communication skills) which might reduce the overall level of patient dissatisfaction are obviously necessary, and some will be proposed.
AUDIT OF AN O P E N A C C E S S N O N - S C R E E N I N G MAMMOGRAPHY POLICY J. J. C U R T I N and M. A. S A M P S O N
Northwick Park Hospital, London There is continuing controversy about the value of m a m m o g r a p h i c screening in asymptomatic women. In particular the low detection rate has been criticized. At Northwick Park Hospital there is an open access policy for both General Practitioner and Breast Clinic referrals for clinically indicated, non-screening m a m m o g r a m s . This study is designed to audit the resultant abnormality yield. Three-hundred and fifty-two consecutive m a m m o g r a m s have been reviewed. All were new referrals. Two hundred and two were from General Practice and 150 from the Consultant-led Breast Clinic. Twenty per cent of cases from the Breast Clinic were reported as showing m a m m o g r a p h i c abnormalities requiring either biopsy or close follow-up. By contrast only 2% of cases from General Practice showed such abnormalities. We conclude that the yield from apparently clinically indicated m a m m o g r a m s referred from General Pi'actice is no higher than in the unselected screening programme. The reasons for and possible implications of these findings are discussed.
B A R I U M ENEMA: A U D I T OF T H E U S E AND U S E F U L N E S S OF AN O P E N ACCESS P O L I C Y B. J. M c K E O W N and M. A. S A M P S O N
Increasing use of non-ionic contrast media for routine imaging of the transplanted kidney has stimulated concern about the potential nephro. toxicity of these media. We report the results of a prospective study to assess possible nephrotoxicity in renal transplant patients. Levels of urinary enzyme activity (AAP, G G T and N A G ) were Used as markers of renal damage. These enzymes were measured before, immediately after and up to 72 hours following injection of non-ionic contrast in two groups of patients undergoing intravenous angiography. There were 26 patients with a renal transplant and 10 controls with normal renal function. All patients showed a transient rise in the levels of urinary enzyme activity, which peaked within 24 h and returned to pre-investigation levels within 72 hours. In the transplanted group the baseline levels of the three marker enzymes was higher and the response greater in magnitude following contrast injection. Nevertheless, the duration of the response was the same as in the control group, with all patients returning to their baseline levels of enzyme activity. F r o m these data it is concluded that whilst a transplanted kidney is more sensitive to the effects of non-ionic contrast than a native kidney, its potential for recovery is unimpaired. ABBREVIATING T H E I N D I V I D U A L I Z E D I V U - IS IT WORTHWHILE? D. N A G , M. B R I L E Y and E. W. L. F L E T C H E R
John Radcliffe Hospital, Oxford Intravenous urography constitutes a significant part of the workload of radiology departments. The standard I V U m a y consist of seven or more radiographs. We performed a pilot prospective study to assess whether the n u m b e r of radiographs taken routinely during IVUs could be reduced. Our study comprised 50 consecutive adults attending for an IVU. All patients had a 'standard IVU' under the supervision of a radiologist who prospectively sought selected radiographs. A provisional report was made on the abbreviated series and independently assessed by a second radiologist. Finally, radiographs from the 'standard series', not initially seen, were checked for additional diagnostic information. The abbreviated IVU consisted o f 5.5 radiographs (mean): in 30 (60%) cases five or less radiographs constituted a diagnostic IVU. The immediate radiograph (nephrogram) could be omitted in 42 (84%) and the compression view in 27 (54%). The post-voiding view, indications for which were agreed with our urologists was required in 28 (56%). This approach allows reduction of the effective dose equivalent (EDE) by as m u c h as 50% to 2.8 mSv per examination with additional financial benefits. We present the results of a questionnaire sent to 30 consultant radiologists seeking their vie';vs on IVU protocols. M A G N E T I C R E S O N A N C E I M A G I N G - A D I A G N O S T I C TOOL TO DIFFERENTIATE LYMPHOEDEMA, PHLEBOEDEMA AND L I P O E D E M A O F THE LOWER E X T R E M I T Y K. D. H A G S P I E L , ST. D U E W E L L , M. M c P H I L L I P S , E. FRICK, A. B O L L I N G E R and G. K. YON S C H U L T H E S S
University Hospital Ziirich, Zi~rieh, Switzerland
Northwick Park Hospital, London The barium enema is a commonly requested diagnostic procedure in hospital and general practice. The policy at Northwick Park Hospital is open access for General Practitioners. This study is designed to audit this policy with respect to diagnostic yield. In addition, we investigated the usefulness of a negative report in general practice, and the effect upon referral patterns. One thousand and fifty six referrals for barium enema were studied. GP requests constituted 24% with an average age of 61.7 years against 62.5 years for hospital referrals. A standard questionnaire was sent to General Practitioners receiving a normal report in order to assess the influence of the investigation on their decision to refer. The overall diagnostic yield was 28 % (GP cases 18 %, hospital cases 32%). The specific pick up rates with respect to clinical presentation are discussed. In a significant n u m b e r o f cases a normal report obviated the need for hospital referral. Our study has demonstrated that for a similar age distribution, General Practitioner referrals for barium enema examinations have a lower diagnostic yield for both benign and malignant disease than hospital referred cases. However, we emphasize the value of a normal examination in the reduction of referrals to hospital outpatient clinics.
The differential diagnosis of the swollen leg is usually based on clinical findings, but contrast examinations m a y be required, particularly to differentiate lymphoedema from venous oedema. To assess the usefulness of magnetic resonance imaging (MRI) we investigated 22 patients with lipoedema, lymphoedema or venous oedema on our 1.5 Tesla system. In each patient transaxial T1- and T2weighted spin echo (SE) sequences were obtained. After the application of G d - D O T A dynamic Gradient Echo scans were performed and the Tl-weighted SE scan was repeated. Lipoedema was easy to differentiate from the other two types of oedema because of its grossly and homogeneously enlarged subcuta" neous layer with no signal increase on T2-weighted sequences or after G d - D O T A . Patients with venous oedema showed diffuse collections of liquid-containing structures within the whole subcutis, whereas these were confined more or less to the layer between muscle and subcutis in lymphoedema. These structures were not found in patients with lipoedema and showed a marked signal increase in T2-weighted sequences and a slight one after G d - D O T A , somewhat more in lymphoedema than in venous oedema. Our results suggest that M R I is an appropriate tool for differentiation between different forms of oedema of the leg.