- Email: [email protected]
The role of computed tomography in the assessment of response to limb compression in unilateral lymphoedema
358
CLINICAL RADIOLOGY
This paper presents the authors" experience of the technique in 49 patients with primary or secondary infertility referred with a diagnosis of proximal tubal occlusion 9 16/49 (33%) patients were found to have patent tubes on preliminary hysterosalpingography (HSG), hence did not require catheterization. Tubal recannalization was successful in 24 of the remaining 33 patients (73%). Two further patients were found to have distal occlusions following successful proximal recannalization. 6/24 patients (25%) became pregnant within 1 year, two subsequently h a d second pregnancies (i.e. 33% pregnancy rate). There were two spontaneous miscarriages and two ectopic pregnancies; one of these patients subsequently had a normal live birth. This study has therefore confirmed the American experience that fallopian tube catheterization is a worthwhile technique and should be considered before tubol surgery for the treatment of proximal tubal occlusions. T H E USE OF C O N T R A S T - E N H A N C E D CT FOR T H E STUDY OF RENAL F U N C T I O N A N D P H Y S I O L O G Y P. D A W S O N and A. M. PETERS
Department of Radiology, Hammersmith Hospital, London CT numbers accurately reflect contrast agent concentrations in blood vessels and tissues and serial measurements during dynamic bolus contrast-enhanced CT may, in principle, be used to monitor the arrival and distribution of the agent. This offers the potential for quantitative studies of physiology and function in health and disease, a potential surprisingly little exploited. We have used 5 s dynamic C T scanning of the kidneys following bolus contrast injection m routine chmcal pahents with biochemically normal renal function and have applied theory initially developed from PET to calculate physiological and functional parameters. Highly consistent data for G F R per unit volume of kidney, a new measure, of ~ 0.6 ml/min/ml was obtained together with a value of 30% for the proportion of kidney volume occupied by blood, a difficult parameter to measure by any other means. The data have also allowed us to answer the age old question, ' W h a t is the nephrogramT Contrary to general wisdom, the 'immediate' nephrogram is some 50% blood pool contribution. Even at 2 min after injection it is still about 20% blood pool. The results demonstrate a new facet of the great potential of CT for functional studies. The implications and some other apolications will be indicated. IV C O N T R A S T I N J E C T I O N S BY R A D I O G R A P H E R S F O R COMPUTER TOMOGRAPHY C. G O S L I N G , J. B A R B E R , H. G. LEWIS-JONES and A. G A S H
Department of Radiology, Walton Hospital, Liverpool The extended role of the Radiographer has been one of the foremost issues within the Radiographic profession. It was felt that there were potential benefits to be gained for this CT service by training Radiographers to inject contrast media. W e present a training programme, guidance and guidelines devised by our Radiology Directorate, which efficiently trains Radiographers to a competent level for i.v. contrast injection. We present a formal delegation process that is required to allow a Radiographer to inject contrast on a Radiologist's behalf, and present a questionnaire that is routinely used by Radiographers to identify patients at potential risk of adverse reaction. We have audited the 1900 injections performed over an 8 m o n t h period; few complications arose and were all minor and in accordance with the accepted rate of such reactions. In 12 cases, Radiographers failed to find a vein and the delegating Radiologist was called to assist. The majority of these failures occurred early in the scheme 9 We present figures that show the introduction of this scheme has improved throughput and efficiency of our CT scanner.
ARE NON-IONIC CONTRAST AGENTS THRQMBOGENIC? C. COUSINS, D. D U T K A , A. B R A D S H A W and P. D A W S O N
Departments of Radiology, Cardiology and Haematology, Hammersmith Hospital and Royal Postgraduate Medical School, London It has been suggested that non-ionic intravascular iodinated contrast agents have in vivo thrombogenic potential. A prospective study during angiography was performed to investigate this hypothesis. Blood was taken from a series of patients during clinical angiography,
before and after arterial puncture and catheterization, but pre-contrast administration, and at 15 and 30 rain after iodinated agents, both ionic and non-ionic. Fragments I and 2 were measured by ELISA assay to indicate the degree of thrombin activation. The circulating level of fragments 1 and 2 before angiography was 1.42 + 0.13 nmol/1 (n = 12, mean _+S.E.M.) which was significantly higher than in normal controls (0.84+0.068, n = 2 0 , P<0.001). After arterial puncture and catheterization a small increase in fragments 1 and 2 was demonstrated (1.61 _+0.22, P - 0 . 2 4 ) . No significant change was found after contrast injection at either 15 min (1.33 + 0.12, P =0.61) or 30 min (1.53+0.14, P - 0 . 5 7 ) after arterial catheterization. There was no difference in this trend between either ionic or non-ionic contrast agents. This study has found no evidence that contrast agents, either ionic or non-ionic, have thrombogenic effects and the trend for thrombin activation during angiography may be secondary to vascular injury. T H E R O L E O F C O M P U T E D T O M O G R A P H Y IN T H E A S S E S S M E N T OF R E S P O N S E T O LIMB C O M P R E S S I O N IN UNILATERAL LYMPHOEDEMA C. D. COLLINS, C. B A D G E R , H. D ' E T T O R R E , D. M c D E R M O T T , R. A ' H E R N , P. S. M O R T I M E R and E. C. M O S K O V I C
Departments ~?fRadiology, Dermatology and Computing, Royal Marsden Hospital, London In lymphoedema external limb support is considered the treatment of choice but no ideal method of monitoring response currently exists. This prospective study uses computed tomography (CT) to quantify changes in cross-sectional area (CSA) and density following compression therapy and to evaluate the efficacy of two different types of compression therapy. Twenty-seven patients with-chronic unilateral lymphoedema were randomized to receive either multi-layer compression bandaging for 3 weeks followed by elastic hosiery for 9 weeks (Group A) or hosiery alone for 12 weeks (Group B). CT examination of abnormal and normal limbs was performed on three separate occasions. The standardized CSA and mean densities of the subcutaneous and muscle compartments of abnormal limb were calculated and compared to the normal side. A significant decrease in CSA of the proximal ( P - 0 . 0 2 ) and distal ( P - 0 . 0 0 2 ) portions of the subcutaneous compartments was demonstrated; changes in CSA of the muscle and bone compartments were not significant. Although the overall percentage decrease in CSA of the subcutaneous compartment was greater in group A than group B the difference was not statistically significant. Analysis of the pattern of decrease in CSA revealed that this was significantly greater between scans 1 and 2 than between 2 and 3 for the distal portion ( P = 0 . 0 2 ) and that group A did significantly better than group B (P=0.006). Significant differences were also present in the densiU, measurements of the subcutaneous ( P - 0 . 0 0 1 ) and muscle ( P - 0 . 0 3 ) compartments. This study demonstrates a significant decrease in CSA of the subcutaneous compartment to compression therapy; this can be objectively quantified using CT. EFFECT O F I N T R A V E N O U S C O N T R A S T M E D I U M ON RENAL RESISTIVE INDEX A. C. D O W N I E , D. C. H O W L E T T , D. J. R O E B U C K and L. M. M a c D O N A L D
Department ~f Radiology, St Thomas' Hospital, London The mechanisms of contrast nephrotoxicity are incompletely understood, but changes in renal blood flow have been considered a possible factor. Doppler ultrasound provides a non-invasive method of investigating renal haemodynamics, and we have used this technique to study the effects of non-ionic contrast medium on renal vascular resistance in healthy subjects undergoing intravenous urography. Resistive index (RI) and pulsatility index (PI) were measured from the interlobar arteries of the right kidney before and at 2 min intervals after injection of a standard dose of 0.8 ml/kg of iopamidol 370. Blood pressure and pulse were recorded at similar intervals. Of 20 patients studied, 11 met our definition of normal subjects, while nine were excluded. Both RI and PI showed a small rise of 2-4% at 2 min, followed by a steady decline over the next 18 min. The m a x i m u m change in RI was - 4 . 3 % (at 20 min), and in PI - 7 . 2 % (at 10 min). While the latter was just significant (95% confidence limits -- 1.6% to - 12.7%), overall the percentage changes were small. There was a slight decline in mean arterial pressure, maximal at 20 min, of - 3 . 7 % ( - 0 . 9 % t~ --6.5%). Intravenous iopamidol in standard dose has a minimal effect on renal haemodynamics in h u m a n subjects as measured by Doppler ultrasound.
CLINICAL RADIOLOGY
This paper presents the authors" experience of the technique in 49 patients with primary or secondary infertility referred with a diagnosis of proximal tubal occlusion 9 16/49 (33%) patients were found to have patent tubes on preliminary hysterosalpingography (HSG), hence did not require catheterization. Tubal recannalization was successful in 24 of the remaining 33 patients (73%). Two further patients were found to have distal occlusions following successful proximal recannalization. 6/24 patients (25%) became pregnant within 1 year, two subsequently h a d second pregnancies (i.e. 33% pregnancy rate). There were two spontaneous miscarriages and two ectopic pregnancies; one of these patients subsequently had a normal live birth. This study has therefore confirmed the American experience that fallopian tube catheterization is a worthwhile technique and should be considered before tubol surgery for the treatment of proximal tubal occlusions. T H E USE OF C O N T R A S T - E N H A N C E D CT FOR T H E STUDY OF RENAL F U N C T I O N A N D P H Y S I O L O G Y P. D A W S O N and A. M. PETERS
Department of Radiology, Hammersmith Hospital, London CT numbers accurately reflect contrast agent concentrations in blood vessels and tissues and serial measurements during dynamic bolus contrast-enhanced CT may, in principle, be used to monitor the arrival and distribution of the agent. This offers the potential for quantitative studies of physiology and function in health and disease, a potential surprisingly little exploited. We have used 5 s dynamic C T scanning of the kidneys following bolus contrast injection m routine chmcal pahents with biochemically normal renal function and have applied theory initially developed from PET to calculate physiological and functional parameters. Highly consistent data for G F R per unit volume of kidney, a new measure, of ~ 0.6 ml/min/ml was obtained together with a value of 30% for the proportion of kidney volume occupied by blood, a difficult parameter to measure by any other means. The data have also allowed us to answer the age old question, ' W h a t is the nephrogramT Contrary to general wisdom, the 'immediate' nephrogram is some 50% blood pool contribution. Even at 2 min after injection it is still about 20% blood pool. The results demonstrate a new facet of the great potential of CT for functional studies. The implications and some other apolications will be indicated. IV C O N T R A S T I N J E C T I O N S BY R A D I O G R A P H E R S F O R COMPUTER TOMOGRAPHY C. G O S L I N G , J. B A R B E R , H. G. LEWIS-JONES and A. G A S H
Department of Radiology, Walton Hospital, Liverpool The extended role of the Radiographer has been one of the foremost issues within the Radiographic profession. It was felt that there were potential benefits to be gained for this CT service by training Radiographers to inject contrast media. W e present a training programme, guidance and guidelines devised by our Radiology Directorate, which efficiently trains Radiographers to a competent level for i.v. contrast injection. We present a formal delegation process that is required to allow a Radiographer to inject contrast on a Radiologist's behalf, and present a questionnaire that is routinely used by Radiographers to identify patients at potential risk of adverse reaction. We have audited the 1900 injections performed over an 8 m o n t h period; few complications arose and were all minor and in accordance with the accepted rate of such reactions. In 12 cases, Radiographers failed to find a vein and the delegating Radiologist was called to assist. The majority of these failures occurred early in the scheme 9 We present figures that show the introduction of this scheme has improved throughput and efficiency of our CT scanner.
ARE NON-IONIC CONTRAST AGENTS THRQMBOGENIC? C. COUSINS, D. D U T K A , A. B R A D S H A W and P. D A W S O N
Departments of Radiology, Cardiology and Haematology, Hammersmith Hospital and Royal Postgraduate Medical School, London It has been suggested that non-ionic intravascular iodinated contrast agents have in vivo thrombogenic potential. A prospective study during angiography was performed to investigate this hypothesis. Blood was taken from a series of patients during clinical angiography,
before and after arterial puncture and catheterization, but pre-contrast administration, and at 15 and 30 rain after iodinated agents, both ionic and non-ionic. Fragments I and 2 were measured by ELISA assay to indicate the degree of thrombin activation. The circulating level of fragments 1 and 2 before angiography was 1.42 + 0.13 nmol/1 (n = 12, mean _+S.E.M.) which was significantly higher than in normal controls (0.84+0.068, n = 2 0 , P<0.001). After arterial puncture and catheterization a small increase in fragments 1 and 2 was demonstrated (1.61 _+0.22, P - 0 . 2 4 ) . No significant change was found after contrast injection at either 15 min (1.33 + 0.12, P =0.61) or 30 min (1.53+0.14, P - 0 . 5 7 ) after arterial catheterization. There was no difference in this trend between either ionic or non-ionic contrast agents. This study has found no evidence that contrast agents, either ionic or non-ionic, have thrombogenic effects and the trend for thrombin activation during angiography may be secondary to vascular injury. T H E R O L E O F C O M P U T E D T O M O G R A P H Y IN T H E A S S E S S M E N T OF R E S P O N S E T O LIMB C O M P R E S S I O N IN UNILATERAL LYMPHOEDEMA C. D. COLLINS, C. B A D G E R , H. D ' E T T O R R E , D. M c D E R M O T T , R. A ' H E R N , P. S. M O R T I M E R and E. C. M O S K O V I C
Departments ~?fRadiology, Dermatology and Computing, Royal Marsden Hospital, London In lymphoedema external limb support is considered the treatment of choice but no ideal method of monitoring response currently exists. This prospective study uses computed tomography (CT) to quantify changes in cross-sectional area (CSA) and density following compression therapy and to evaluate the efficacy of two different types of compression therapy. Twenty-seven patients with-chronic unilateral lymphoedema were randomized to receive either multi-layer compression bandaging for 3 weeks followed by elastic hosiery for 9 weeks (Group A) or hosiery alone for 12 weeks (Group B). CT examination of abnormal and normal limbs was performed on three separate occasions. The standardized CSA and mean densities of the subcutaneous and muscle compartments of abnormal limb were calculated and compared to the normal side. A significant decrease in CSA of the proximal ( P - 0 . 0 2 ) and distal ( P - 0 . 0 0 2 ) portions of the subcutaneous compartments was demonstrated; changes in CSA of the muscle and bone compartments were not significant. Although the overall percentage decrease in CSA of the subcutaneous compartment was greater in group A than group B the difference was not statistically significant. Analysis of the pattern of decrease in CSA revealed that this was significantly greater between scans 1 and 2 than between 2 and 3 for the distal portion ( P = 0 . 0 2 ) and that group A did significantly better than group B (P=0.006). Significant differences were also present in the densiU, measurements of the subcutaneous ( P - 0 . 0 0 1 ) and muscle ( P - 0 . 0 3 ) compartments. This study demonstrates a significant decrease in CSA of the subcutaneous compartment to compression therapy; this can be objectively quantified using CT. EFFECT O F I N T R A V E N O U S C O N T R A S T M E D I U M ON RENAL RESISTIVE INDEX A. C. D O W N I E , D. C. H O W L E T T , D. J. R O E B U C K and L. M. M a c D O N A L D
Department ~f Radiology, St Thomas' Hospital, London The mechanisms of contrast nephrotoxicity are incompletely understood, but changes in renal blood flow have been considered a possible factor. Doppler ultrasound provides a non-invasive method of investigating renal haemodynamics, and we have used this technique to study the effects of non-ionic contrast medium on renal vascular resistance in healthy subjects undergoing intravenous urography. Resistive index (RI) and pulsatility index (PI) were measured from the interlobar arteries of the right kidney before and at 2 min intervals after injection of a standard dose of 0.8 ml/kg of iopamidol 370. Blood pressure and pulse were recorded at similar intervals. Of 20 patients studied, 11 met our definition of normal subjects, while nine were excluded. Both RI and PI showed a small rise of 2-4% at 2 min, followed by a steady decline over the next 18 min. The m a x i m u m change in RI was - 4 . 3 % (at 20 min), and in PI - 7 . 2 % (at 10 min). While the latter was just significant (95% confidence limits -- 1.6% to - 12.7%), overall the percentage changes were small. There was a slight decline in mean arterial pressure, maximal at 20 min, of - 3 . 7 % ( - 0 . 9 % t~ --6.5%). Intravenous iopamidol in standard dose has a minimal effect on renal haemodynamics in h u m a n subjects as measured by Doppler ultrasound.