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Reproducibility of in vitro doppler ultrasound measurements
ABSTRACTS were malignant and the nature of seven (19%) of these nodules could not be determined. In this series of patients undergoing staging CT for lung cancer, over 70% of pulmonary nodules proved to be benign and we conclude that this high incidence of benign nodules should be taken into account when interpreting a staging CT for lung cancer.
SHIFTING RADIOLOGY: CLINICAL METHOD OR TAKEOVER? T. S H E R W O O D
Department of Radiology, Addenbrooke's Hospital, Cambridge The advance of imaging has led to interesting changes in bedside diagnosis: why should clinicians have to battle with M u r p h y ' s sign or Courvoisier's law, quite often wrong, when we can readily show what is really going on with gall-bladder ultrasound? If the acute or chronic abdomen now demands ultrasound and other imaging assessment, why not begin there, and make radiologists a first port of call for referral of certain patients? High falutin considerations rear up at once, including science and perception as well as economy. W h a t is best for the patient? A n d for radiologists? The claims of scientific medicine and radiology will be examined in an attempt to find answers. The conclusion is by William Blake: 'No bird soars too high if he soars with his own wings'.
R E P R O D U C I B I L I T Y O F IN VITRO D O P P L E R U L T R A S O U N D MEASUREMENTS R. W. J. H A R T L E Y and P. M. T A Y L O R
gates up to 40 ,u diameter. SEM of a 5/~ filter showed that m a n y pores were unobstructed after filtration of 10 ml of fluid. Material i~dherent to the tip was shown on LM a n d SEM to consist of red cells surrounded by a condensed fibrin/platelet shell. The device is rapidly effective in producing thrombolysis with little particulate material released and may be suitable for use in coronary and peripheral arteries and bypass grafts.
A N E U R Y S M A L DISEASE OF T H E S P L A N C H N I C ARTERIES: DIAGNOSIS A N D M A N A G E M E N T J. E. J A C K S O N and M. J. K. B L O M L E Y
Radiodiagnosis Department, Hammersmith Hospital, London Thirteen patients with aneurysmal disease of the splanchnic arteries were treated at our hospital over a 6 year period. Eight had aneurysms in the gastroduodenal artery, two in the hepatic artery, two in the splenic artery and one in the superior mescnteric artery. Presentation and diagnosis are reviewed. Eleven were treated by transcatheter embolization and two by surgery. Embolization was successful in all cases though in one patient it was feasible in only one out of two lesions. Apart from one patient with a partial splenic infarct, there were no complications and no recurrences have been reported. Surgery was also successful in both patients; there was significant morbidity in one. Technical aspects of transcatheter embolization will be discussed. Where feasible, all patients with suspected visceral artery aneurysms should have angiography, and embolization should be considered as first-line therapy.
Department of Clinical Radiology, Manchester Royal Infirmary, Manchester
B O L U S CHASING: A N E W T E C H N I Q U E IN P E R I P H E R A L ARTERIOGRAPHY E. J U R R I A A N S and I. P. W E L L S
Introduction andAims: Doppler ultrasound measurement of blood flow velocity is widely used in clinical practice and has been utilized in the evaluation of renal transplants. Results in the latter have been conflicting. Possible sources of discrepancy are intra- and inter-observer variation. The aim of this study was to assess the magnitude of these variations in vitro using a Doppler flow phantom. Methods: The p h a n t o m used a blood mimicking fluid circulated by a variable speed m o t o r with pulsatility produced by a cam occlusor. The same pulse rate was used for all experiments. Five different m a x i m u m velocities were presented in r a n d o m order to six observers. Each observer was asked to measure the m a x i m u m velocity and calculate the resistive index (RI). The observations were performed on two occasions, one week apart. All measurements were made using an Acuson 128 system with observers blind to the measured and calculated parameters. Results: The measurements for m a x i m u m velocity obtained by the six observers were 26, 58, 87, 108 and 119 crn/s with standard deviation of 3.6, 5.4, 11.4, 11.7 and 9.6 cm/s. A similar magnitude of variation between observers was present in the calculated RI. When data from the first and second observers' examinations was compared, a correlation coefficient of 0.94 for m a x i m u m velocity and 0.82 for the RI was calculated. Conclusions: The results demonstrate significant intra- and interobserver variation. Mechanisms for the possible causes and reduction of these variations have been identified.
Department of Radiology, Derriford General Hospital, Plymouth
INTRAVASCULAR THROMBUS ABLATION - EVALUATION OF A N E W P E R C U T A N E O U S U L T R A S O N I C DEVICE G. G. H A R T N E L L , S. F R I E D L , J. SAXTON, U. R O S E N S C H E I M * and G. S. A. A B E L A
Departments of Cardiology, New England Deaconess Hospital, Harvard Medical School, Boston, USA and *Tel-Aviv University, TeL Aviv, Israel Conventional thrombolysis is not always successful and is contraindicated in many patients. An ultrasonic device has been developed which may be suitable for percutaneous peripheral or coronary thrombolysis. It can be introduced over a guidewire through a 10-F guiding catheter or 6-F sheath. Efficacy and safety were tested in a series of 26 p h a n t o m experiments using clotted blood in an aorta/coronary phantom. The ultrasonic transmission wire has a specially designed 1.6 m m tip energized by a computer controlled pulse generator. Clot drawn into a vortex near the tip is rapidly ablated (typically 200 m g clot within 2 rain at 20 W). • Examination of effluent fluid produced by ultrasonic thrombolysis showed no visible particles. Light microscopy (LM) of centrifuged fluid showed little solid material, mainly filamentous fibrin/platelet aggre-
431
Current digital angiographic equipment enable images to be acquired in both subtracted and non-subtracted form, are capable of digital fluoroscopy and permit real-time monitoring of acquired images. Of particular note is the development of a new technique of peripheral vascular imaging called digital scanning or bolus chasing. Bolus chasing permits the radiologist to visualize the bolus of contrast medium and to follow it in real-time, while acquiring non-subtracted images at a suitable frame rate. In this paper, the technique of bolus chasing is described. Furthermore, comparison with conventional peripheral angiography is made. Bolus chasing is an expedient way of performing a peripheral angiogram and compared to conventional angiography reduces the patient and radiologist radiation dose while improving image quality.
N E W S T A N D A R D S OF I M A G I N G P R I O R T O VARICOSE VEIN SURGERY K. D. McBRIDE, P. A. G A I N E S and J. D. B E A R D *
Departments of Radiology and * Vascular Surgery, Royal Hallamshire Hospital, SheffieM Varicose veins and their complications are a significant cause of morbidity. The incidence of recurrence is often high, and a 'cure' m a y be difficult, or impossible, to achieve. With more refined pre-operative techniques, the management o f recurrent disease and severe primary disease should be improved. In a group of 41 patients, 55 varicograms were performed preoperatively. Of these, five studies were undertaken for primary varicosities, the remainder having recurrent disease. There were 16 males and 25 females, with an average age of 51 years. Surgery had been performed, on average, 9 years earlier, with only a 4 year interval to disease recurrence. The patients also underwent ambulatory venous pressure studies where appropriate and 25 had colour Doppler imaging for improved localization of perforator incompetence and sapheno-femoral incompetence. Twelve also had comparative modified ascending phlebography at the time of varicography. Calf perforator incompetence was demonstrated in 53 limbs, short saphenous incompetence in 20 limbs, mid-thigh perforator incompetence in 37 limbs and sapheno-femoral junction incompetence in 26 limbs. Appropriate surgery was performed on 27 patients with a further 12 awaiting treatment, and two others having conservative treatment. Preoperative varicography and ultrasound localization provided accurate information on disease localization. It is anticipated that the recurrence rate will be low. A long-term prospective study is being undertaken.
SHIFTING RADIOLOGY: CLINICAL METHOD OR TAKEOVER? T. S H E R W O O D
Department of Radiology, Addenbrooke's Hospital, Cambridge The advance of imaging has led to interesting changes in bedside diagnosis: why should clinicians have to battle with M u r p h y ' s sign or Courvoisier's law, quite often wrong, when we can readily show what is really going on with gall-bladder ultrasound? If the acute or chronic abdomen now demands ultrasound and other imaging assessment, why not begin there, and make radiologists a first port of call for referral of certain patients? High falutin considerations rear up at once, including science and perception as well as economy. W h a t is best for the patient? A n d for radiologists? The claims of scientific medicine and radiology will be examined in an attempt to find answers. The conclusion is by William Blake: 'No bird soars too high if he soars with his own wings'.
R E P R O D U C I B I L I T Y O F IN VITRO D O P P L E R U L T R A S O U N D MEASUREMENTS R. W. J. H A R T L E Y and P. M. T A Y L O R
gates up to 40 ,u diameter. SEM of a 5/~ filter showed that m a n y pores were unobstructed after filtration of 10 ml of fluid. Material i~dherent to the tip was shown on LM a n d SEM to consist of red cells surrounded by a condensed fibrin/platelet shell. The device is rapidly effective in producing thrombolysis with little particulate material released and may be suitable for use in coronary and peripheral arteries and bypass grafts.
A N E U R Y S M A L DISEASE OF T H E S P L A N C H N I C ARTERIES: DIAGNOSIS A N D M A N A G E M E N T J. E. J A C K S O N and M. J. K. B L O M L E Y
Radiodiagnosis Department, Hammersmith Hospital, London Thirteen patients with aneurysmal disease of the splanchnic arteries were treated at our hospital over a 6 year period. Eight had aneurysms in the gastroduodenal artery, two in the hepatic artery, two in the splenic artery and one in the superior mescnteric artery. Presentation and diagnosis are reviewed. Eleven were treated by transcatheter embolization and two by surgery. Embolization was successful in all cases though in one patient it was feasible in only one out of two lesions. Apart from one patient with a partial splenic infarct, there were no complications and no recurrences have been reported. Surgery was also successful in both patients; there was significant morbidity in one. Technical aspects of transcatheter embolization will be discussed. Where feasible, all patients with suspected visceral artery aneurysms should have angiography, and embolization should be considered as first-line therapy.
Department of Clinical Radiology, Manchester Royal Infirmary, Manchester
B O L U S CHASING: A N E W T E C H N I Q U E IN P E R I P H E R A L ARTERIOGRAPHY E. J U R R I A A N S and I. P. W E L L S
Introduction andAims: Doppler ultrasound measurement of blood flow velocity is widely used in clinical practice and has been utilized in the evaluation of renal transplants. Results in the latter have been conflicting. Possible sources of discrepancy are intra- and inter-observer variation. The aim of this study was to assess the magnitude of these variations in vitro using a Doppler flow phantom. Methods: The p h a n t o m used a blood mimicking fluid circulated by a variable speed m o t o r with pulsatility produced by a cam occlusor. The same pulse rate was used for all experiments. Five different m a x i m u m velocities were presented in r a n d o m order to six observers. Each observer was asked to measure the m a x i m u m velocity and calculate the resistive index (RI). The observations were performed on two occasions, one week apart. All measurements were made using an Acuson 128 system with observers blind to the measured and calculated parameters. Results: The measurements for m a x i m u m velocity obtained by the six observers were 26, 58, 87, 108 and 119 crn/s with standard deviation of 3.6, 5.4, 11.4, 11.7 and 9.6 cm/s. A similar magnitude of variation between observers was present in the calculated RI. When data from the first and second observers' examinations was compared, a correlation coefficient of 0.94 for m a x i m u m velocity and 0.82 for the RI was calculated. Conclusions: The results demonstrate significant intra- and interobserver variation. Mechanisms for the possible causes and reduction of these variations have been identified.
Department of Radiology, Derriford General Hospital, Plymouth
INTRAVASCULAR THROMBUS ABLATION - EVALUATION OF A N E W P E R C U T A N E O U S U L T R A S O N I C DEVICE G. G. H A R T N E L L , S. F R I E D L , J. SAXTON, U. R O S E N S C H E I M * and G. S. A. A B E L A
Departments of Cardiology, New England Deaconess Hospital, Harvard Medical School, Boston, USA and *Tel-Aviv University, TeL Aviv, Israel Conventional thrombolysis is not always successful and is contraindicated in many patients. An ultrasonic device has been developed which may be suitable for percutaneous peripheral or coronary thrombolysis. It can be introduced over a guidewire through a 10-F guiding catheter or 6-F sheath. Efficacy and safety were tested in a series of 26 p h a n t o m experiments using clotted blood in an aorta/coronary phantom. The ultrasonic transmission wire has a specially designed 1.6 m m tip energized by a computer controlled pulse generator. Clot drawn into a vortex near the tip is rapidly ablated (typically 200 m g clot within 2 rain at 20 W). • Examination of effluent fluid produced by ultrasonic thrombolysis showed no visible particles. Light microscopy (LM) of centrifuged fluid showed little solid material, mainly filamentous fibrin/platelet aggre-
431
Current digital angiographic equipment enable images to be acquired in both subtracted and non-subtracted form, are capable of digital fluoroscopy and permit real-time monitoring of acquired images. Of particular note is the development of a new technique of peripheral vascular imaging called digital scanning or bolus chasing. Bolus chasing permits the radiologist to visualize the bolus of contrast medium and to follow it in real-time, while acquiring non-subtracted images at a suitable frame rate. In this paper, the technique of bolus chasing is described. Furthermore, comparison with conventional peripheral angiography is made. Bolus chasing is an expedient way of performing a peripheral angiogram and compared to conventional angiography reduces the patient and radiologist radiation dose while improving image quality.
N E W S T A N D A R D S OF I M A G I N G P R I O R T O VARICOSE VEIN SURGERY K. D. McBRIDE, P. A. G A I N E S and J. D. B E A R D *
Departments of Radiology and * Vascular Surgery, Royal Hallamshire Hospital, SheffieM Varicose veins and their complications are a significant cause of morbidity. The incidence of recurrence is often high, and a 'cure' m a y be difficult, or impossible, to achieve. With more refined pre-operative techniques, the management o f recurrent disease and severe primary disease should be improved. In a group of 41 patients, 55 varicograms were performed preoperatively. Of these, five studies were undertaken for primary varicosities, the remainder having recurrent disease. There were 16 males and 25 females, with an average age of 51 years. Surgery had been performed, on average, 9 years earlier, with only a 4 year interval to disease recurrence. The patients also underwent ambulatory venous pressure studies where appropriate and 25 had colour Doppler imaging for improved localization of perforator incompetence and sapheno-femoral incompetence. Twelve also had comparative modified ascending phlebography at the time of varicography. Calf perforator incompetence was demonstrated in 53 limbs, short saphenous incompetence in 20 limbs, mid-thigh perforator incompetence in 37 limbs and sapheno-femoral junction incompetence in 26 limbs. Appropriate surgery was performed on 27 patients with a further 12 awaiting treatment, and two others having conservative treatment. Preoperative varicography and ultrasound localization provided accurate information on disease localization. It is anticipated that the recurrence rate will be low. A long-term prospective study is being undertaken.