1979, British Journal of Radiology, 52, 676-679
Proceedings of The British Institute of Radiology Nuclear medicine in paediatrics Abstracts of papers presented at a joint meeting of the British Instituteof Radiology and the Royal College of Physicians of Edinburgh, held on October20,1978 at the Scottish Health Services Centre, Crewe Road, Edinburgh Cardiac and respiratory disease Chairman: Professor J. O. Forfar Paediatric cardiology, by D. L. Gilday. Value of krypton 81m ventilation and 9 9Tc m macro-aggregate lung scans in children, by I. Gordon, G. Ciofetta and F. Fazio. The use of Xenon 133 for lung perfusion visualization in children with heart disease, by J. W. Haggith, H. H. Bain, J. D. Fenwick, A. S. Hunter and M. Heppell. Lung scanning in paediatric practice, by T. H. Macdonald, K. C. Young and P. Horton. The use of 8iKrm t o measure perfusion and ventilation distribution in children—quantitative aspects, by G. Ciofetta, J. M. B. Hughes and M. Silverman. VALUE OF KRYPTON 81m VENTILATION AND MACRO-AGGREGATE LUNG SCANS IN CHILDREN
PAEDIATRIC CARDIOLOGY
By D. L. Gilday
By I. Gordon, G. Ciofetta and F. Fazio
Division of Nuclear Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada The analysis of nuclear angiocardiography is divided into two parts. The first is visual inspection and assessment of the analogue images produced by the gamma camera. These images provide a useful pictorial demonstration of the flow of the bolus through the heart and lungs. The detection of a large left to right shunt is usually seen by this method. Other congenital anatomical defects can also be seen. The main method of analysis of the data regarding left to right shunting is via computer assessment of the timeactivity histogram of the transit through the lungs. The gamma variate analysis of the histogram has an excellent correlation with the Dye and Fick dilution methods (Treves and Malta 1974). The evaluation of right to left shunts can be carried out very effectively using the method described by Gates et al. (1971) which involved the injection of radioactively labelled microspheres of albumin which would impinge on the first vascular bed encountered. This resulted in a biological distribution of the tracer according to the output of the right ventricle. Thus, by quantifying the amount of activity within the lungs as compared with the whole body, one can get an estimate of the amount of blood going to the lungs and the amount of blood shunted. Of recent marked interest is the use of thallium 201 chloride in the evaluation of paediatric heart disease in the newborn. The differentiation of global ischaemia (transient myocardial ischaemia) is very important in that the patient may present as if there was congenital heart disease. The appearance in the thallium scan of minimal activity within the myocardium suggests this diagnosis. In addition the anomalous left coronary artery will cause a defect in the perfusion to the myocardium which is readily assessed. Infundibular hypertrophic subaortic stenosis and other cardiomyopathies are readily detected, diagnosed and differentiated one from another. With the addition of the multiple gated acquisition study one can also assess the overall function of the left ventricle at that time. REFERENCES TREVES, S., MALTZ, D. L., 1974. Radionuclide angiocardi-
ography. Postgraduate Medicine, 56, 99-107. GATES, G. F., ORME, H. W., DORE, E. K., 1971. Measure-
ment of cardiac shunting with technetium labelled albumin aggregates. Journal of Nuclear Medicine, 12, 746-749.
Hospital for Sick Children, Gt. Ormond Street, London WC1 3 TV and Hammersmith Hospital, Du Cane Road, London W12 OHS Krypton 81m has a \ life of 13 sec and is a pure y emitter at 190 KeV. It is eluted from a rubidium generator, the \ life of which is 4.5 hours. The latter is produced by a cyclotron. The child lies supine on the gamma camera and the rubidium generator is eluted with humidified air. An intravenous injection of 99Tm macro-aggregate are injected at the start of the examination. The patients examined fall into four main groups: (A). Establish the diagnosis. This is a relatively small group of patients in whom the combined ventilation/perfusion has either suggested the exact diagnosis or directed the attention of the clinician and diagnostic imager to the abnormal area where the diagnosis has been tentatively suggested. (B). The evaluation of surgical procedures on the pulmonary artery. This technique is valuable in assessing the post-operative patency of the relevant pulmonary artery and thereby the vascularization of the relevant lung. (C). Refute a diagnosis. A normal ventilation/perfusion scan in a child suspected of having either bronchiectasis or a foreign body is very strong evidence that there is no significant disease present. Both anterior and posterior oblique projections must be obtained as well as PA and lateral radiographs. Fluoroscopy is also essential in cases of suspected foreign body. (D) To establish the extent of the disease. Ventilation/perfusion scans are proving to be a very sensitive index of the extent of lung disease in children with chronic lung disease. In children with bronchiectasis who are not responding to adequate active medical therapy and in whom surgery is therefore contemplated, a high quality ventilation/perfusion scan with all four oblique projections may alleviate the need for bronchography. It is essential to combine the information from all modalities of diagnostic imaging step by step in order that the next relevant examination will be carried out. In an area where so many different modalities of investigation are available it is essential that problem-oriented paediatric imaging is practised.
Reprints of these abstracts may be obtained free from the Managing Editor, British Journal of Radiology, 32 Welbeck Street, London W1M 7PG (01-935 6867).
676
AUGUST 1979
Proceedings of The British Institute of Radiology THE USE OF XENON 133 FOR LUNG PERFUSION VISUALIZATION IN CHILDREN WITH HEART DISEASE
By J. W. Haggith, H. H. Bain, J. D. Fenwick, A. S. Hunter and M. Heppell Regional Medical Physics Department, Newcastle upon Tyne This preliminary study was to determine the relative pulmonary perfusion in 16 children with congenital heart disease. The technique involves an intravenous bolus injection of 133Xe in saline with the patient positioned supine over a gamma camera. No special preparation of the patient is required. Serial two-second posterior views of the lungs are obtained using a data-processing system. Timeactivity curves are created for each lung from which the relative lung perfusion may be determined. Right to left shunting can also be detected. These curves facilitated an estimate of the radiation dose. In these patients, for an administered activity of 0.2 /^Ci/kg body weight, the dose is not greater than 10 mrem whole body and 1 5 mrem to the lung mucosa. The technique has been used to demonstrate relative perfusion in patients with systemic arterial to pulmonary arterial anastomoses, with pulmonary stenosis and with pulmonary vascular disease. The method is safe and relatively non-invasive and may prove valuable in the long-term management of these patients.
the use of lung scans. Children who had radiotherapy for lung secondaries from solid tumours, e.g. Wilm's tumour, showed some reduction in distribution to the lung receiving radiotherapy. This reverted to normal after many months. In 33 children with scoliosis we have shown that the bias (the percentage by which the activity of the more active lung exceeds the less active) of perfusion and ventilation increases as the angle of curvature increases. Preliminary findings also suggest that perfusion is reduced in the concavity of the curve but this matter requires further investigation. In conclusion we would suggest that with the scintillation camera facilities available in most teaching hospitals, a clinician (in this case a paediatrician) can obtain information which is of relevance in the routine clinical care of patients.
THE USE OF 81Krm T O MEASURE PERFUSION AND VENTILATION DISTRIBUTION IN CHILDREN QUANTITATIVE ASPECTS
By G. Ciofetta*, J. M. B. Hughes and M. Silverman Royal Postgraduate Medical School, Hammersmith Hospital, London, W. 12
The continuous inhalation of 81 Kr m (tj 13 sec) allows images of lung ventilation to be recorded using a gamma camera (Fazio and Jones, 1975). Detection of regional ventilation defects is possible using this technique during normal breathing and therefore without the patient's co-operation and with minimal radiation exposure. LUNG SCANNING IN PAEDIATRIC PRACTICE Application of 8 1 Kr m ventilation studies in children is complicated by the very fast ventilatory turnover (V/VOL) T. H. Macdonald frequently found in neonates and infants. Under these conditions equilibrium between regional inspired and Royal Hospital for Sick Children, Glasgow expired isotope concentration may occur, despite the very rapid physical decay and the 81 Kr m images may reflect lung K. C. Young and P. Horton volume rather than ventilation distribution. Images recorded during continuous intravenous inDepartment of Clinical Physics and Bio-Engineering, Glasgow fusion of 8 1 Kr m dissolved in 5% dextrose, reflect lung Regional lung function studies are of value in paediatrics perfusion but are also affected by the distribution of ventiparticularly between 18 months and 5 years, a period when lation. This occurs because radioactive gas evolved into the standard lung function tests are rarely applicable. Since alveoli is removed by ventilatory washout (V/VOL) September 1976 we have performed almost one hundred (Ciofetta et al., 1978). It is possible to measure ventilatory lung scans in children aged six weeks to seven years. These washout (V/VOL) regionally in absolute units (1. min -1 . 1-1) 133 studies were performed using Xe. Ventilation and from the clearance curves of inhaled and infused 81 Kr m . perfusion studies were performed in the upright position This measurement allows a more accurate interpretation using a gamma camera linked to a data analysis facility. Lung of the 8 iKr m ventilation and perfusion images in infants and images were recorded at one second intervals, were displayed children. Some practical examples were presented to illuson a colour television screen, and analysed to determine trate the clinical use of this quantitative analysis. distribution indices and mean fractional turnover rates for the upper and lower zones of each lung. The distribution REFERENCES indices were helpful in identifying small lungs or lung areas FAZIO, F. and JONES, T., 1975. Assessment of regional with a reduced contribution to ventilation or perfusion, e.g. ventilation by continuous inhalation of radioactive bronchiectasis. In the latter case non-functioning lung tissue krypton-81m. British Medical Journal, 3, 673-676. could be removed. Reduction in distribution and of fracCIOFETTA, G., PRATT, T. A. and HUGHES, J. M. B., 1978. tional turnover was used to identify conditions such as the Comparison of krypton-81m and technetium-99m hypoplastic lung syndrome, and a pattern of ventilation and human serum albumin for measurement of pulmonary perfusion mismatching, together with reduced turnover perfusion distribution. In: Clinical and Experimental rates, to identify a diffuse emphysema in a very young Applications of Krypton-81m. British Journal of Radiinfant. In one patient, turnover in the perfusion study was ology, Special Report No. 15, 38-45. considerably prolonged when compared with the ventilation study. Biopsy demonstrated pulmonary eosinophilia. The abnormality in the perfusion study reverted to normal with *Present address: II Clinica Pediatrica, Universita degli corticosteroid therapy and treatment could be monitored by Studi, Roma, Italy.
677
VOL.
52, No. 620 Proceedings of The British Institute of Radiology
Urinary tract Chairman: Professor J. S. Robson Measurement of separate renal function with 197HgCl2, by C. Raynaud. Early detection of renal damage, by M. V. Merrick, W. S. Uttley and R. Wild. Direct radionuclide cystography, by A. R. Constable. A comparison of nuclear medicine and excretion urography in the follow-up of ileal loop diversion, by J. D. Orr, M. V. Merrick, R. Wild and I. S. Kirkland. on the RIK than on EU, in nine kidneys. These were segmented defects not associated with deformation of the perirenal fat. It is concluded that the RIK is more sensitive than EU By C. Raynaud for detecting segmented scars, but the EU is the better technique for the detection of concentric cortical loss. Service Hospitalier Frederic Joliot, Departement de Biologie, A technique of detecting vesico-ureteric reflux (VUR) at Commissariat a VEnergy Atomique, 91406 Orsay, France the end of the renal function examination using TcDTPA When radiomercury is injected in soluble form such as was described. The technique is comparable in sensitivity to 197 HgCl2, renal activity rises slowly to a plateau of 19 to the radiographic micturating cystourethrogram, but avoids 19-5% of the injected dose in the normal subject, within 24 the need for catheterization. hours. It remains at this level for several days. Uptake, generally measured at the second or the third day, depends on the functional activity of the renal parenchyma. It is increased if renal function is increased, and decreased if renal function is decreased. It is significantly correlated with DIRECT RADIONUCLIDE CYSTOGRAPHY inulin and PAH clearances, and Tm of PAH. The measurement is generally made by quantitative By A. R. Constable scintigraphy using a gamma camera or a rectilinear scanner. Two corrections are used, one for kidney depth, the other Institute of Urology, St. Pauls Hospital, Endell Street, for liver interference. Results calculated as a percentage of London, WC2 the injected dose are finally expressed as a percentage of normal, the normal values being 100±13% of normal mean During the normal course of diagnosis and treatment of for each kidney, and 100 ± 11 % of normal mean for global vesico-ureteric reflux (VUR), children will frequently be exposed to a considerable radiation dose from intravenous uptake. The Hg uptake test is useful to the urologist who needs urograms (IVU's) and micturating cystourethrograms a reliable measure of the functional state of each kidney, for (MCU's). Radionuclide cystography (RNC) normally results in a example in obstructive uropathies, where he must decide between conservative surgery and nephrectomy. It is also radiation dose about a hundred times smaller than the useful when evaluating the efficiency of medical or surgical corresponding radiographic procedure. The diagnostic therapy. It is especially useful when assessing compen- reliability of RNC has been shown to be similar to that of MCU and this, together with the favourable dosimetry, satory hypertrophy. The weakness of this technique is the radiation dose suggests that the technique should be included in the normal absorbed by the kidneys, which197amounts to 9 rad in young management protocol for these patients. Although the quest m for a completely atraumatic VUR investigation favours the children. Attempts to replace HgCl by "Tc -DMSA, 2 "Tc m -TMA, and radioactive bismuth were not successful, indirect RNC methods, the direct (per catheter) method is due to the lack of reproducibility with DMSA and TMA, generally thought more suitable for children and for patients with outflow abnormalities. and high urinary excretion of Bi. The results of a recent study comparing radiographic and If carefully controlled, by arteriography for example, the radionuclide techniques and the place of RNC in a suggested Hg uptake test temains extremely useful. protocol were discussed. MEASUREMENT OF SEPARATE RENAL FUNCTION WITH
EARLY DETECTION OF RENAL DAMAGE
By M. V. Merrick, W. Uttley and R. Wild Royal Hospital for Sick Children and Western General Hospital, Edinburgh Radioisotope imaging of the kidney (RIK) was compared with excretion urography (EU) in 79 children (155 kidneys) with urinary tract infections. Scans were performed not less than one hour after the intravenous administration of 75 yCi/kg of technetium dimercaptosuccinate. The standard radiographic technique of EU was modified as necessary by the radiologist performing the examination. Ninety-seven kidneys were considered normal by both techniques; in a further 46 both were abnormal, and showed a similar extent of renal cortical loss. There was a discrepancy in 12 cases. Cortical loss was present on the EU in three children with a normal RIK. In one case there was movement on the RIK. The other two had concentric cortical loss. Defects were present, and were more extensive
A COMPARISON OF NUCLEAR MEDICINE AND EXCRETION UROGRAPHY IN THE FOLLOW-UP OF ILEAL LOOP DIVERSION
By J. D. Orr, M. V. Merrick, R. Wild and I. S. Kirkland Departments of Surgical Paediatrics, Nuclear Medicine and Radiodiagnosis, University of Edinburgh, Western General Hospital, Edinburgh Progressive deterioration of the upper urinary tract occurs in many children who have undergone urinary diversion. Early detection of this deterioration is difficult as biochemical investigations give little indication of early damage, and although excretion urography gives adequate morphological detail of the kidney, it is not a satisfactory
678
AUGUST 1979
Proceedings of The British Institute of Radiology method of assessing renal function. It is hoped that more sophisticated radioisotope techniques might detect change at an early stage. A small group of 24 patients in whom the original indication for diversion had been myelomeningocoele were investigated, on average 12 years after operation. From this group 47 kidneys were available for study. The excretion urogram was carried out in a standard manner. The radioisotope investigations were performed using a gamma camera on line to a dedicated mini-computer. For the initial dynamic study "renograms" were obtained utilizing " T c m DTPA, and on the following day renal scans were obtained 2-4 hours after injection of Tc DMS. The results obtained from the differing techniques were then
compared. On initial comparison both techniques were found to be in concordance in 85% of the kidneys compared, but when the amount of information obtained from each investigation was considered, although found to be similar in 75%, in 17% the radioisotope methods gave more information. Overall the combined radioisotope technique gave more information concerning the morphology, total renal function and relative function of both kidneys, especially when renal function was poor. Scanning could be carried out at lower risk, lower radiation dose and lower cost. Therefore, it is considered a suitable method of follow-up in this group of patients. Where necessary further morphological information can always be obtained from the excretion urogram.
General topics Chairman: Dr. J. P. Lavender Bone imaging in paediatrics, by D. Gilday. Gastro-intestinal haemorrhage unrelated to gastric mucosa diagnosed on " T c m pertechnetate scans, by I. Gordon. BONE IMAGING IN PAEDIATRICS
By D. Gilday Division of Nuclear Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada Since the introduction of the phosphate compounds for bone imaging there has been a dramatic utilization of bone scans in paediatric diseases. In most benign diseases of bone the addition of immediate post-injection blood pool images has proven to be extremely valuable in assessing the degree of hyperaemia of the lesion. The use of high resolution and magnification pinhole views in the imaging of lesions, especially those which are avascular, is very important. The focal accumulation of bone radiopharmaceutical associated with the intra-osseus hyperaemia has proven to be a very reliable indicator of osteomyelitis and to separate the latter from cellulitis. The viability of bone after trauma can be readily assessed especially with magnification views. Skeletal pain in childhood is often a diagnostic dilemma, the cause of which can be both detected and characterized by bone imaging. This is especially so in the diagnosis of occult, axial skeleton osteoid osteomas. Although the detection of Legg-Perthes disease is usually made radiologically, in some instances the radiographs may be normal where the bone scan will demonstrate absent deposition of radiotracer in the femoral head, indicating the avascular nature of the disease. Re-vascularization of the femoral head can be readily assessed by the bone scan as it is a sensitive indicator of bone and blood flow.
Neoplasia, both primary and secondary, involving the skeleton can be better assessed by bone scanning using screening gamma camera images and selective high quality, high resolution or magnification images, rather than by radiological skeletal survey (especially in neuroblastoma, lymphoma, leukaemia and bone secondaries from osteogenic and E wing's sarcoma). There are some difficulties in the use of bone imaging in childhood such as the contamination of the skin with radioactive urine which must be prevented at all costs, and the involuntary voiding on the part of young children and infants which may lead to contamination of the clothes or pyjamas.
GASTRO-INTESTINAL HAEMORRHAGE UNRELATED TO GASTRIC MUCOSA DIAGNOSED ON 99 Tc m PERTECHNETATE SCANS By I. Gordon Hospital for Sick Children, London WC1 Small bowel bleeding due to an anastomotic ulcer in one patient and a haemangioma in another were diagnosed by " T c m pertechnetate radioisotope scans. Multiple views of the abdomen during the radioisotope scan proved essential. The rationale of this technique for imaging in cases of haemorrhage from the gastro-intestinal tract was described.
679
Proceedings of The British Institute of Radiology Nuclear medicine in paediatrics Abstracts of papers presented at a joint meeting of the British Instituteof Radiology and the Royal College of Physicians of Edinburgh, held on October20,1978 at the Scottish Health Services Centre, Crewe Road, Edinburgh Cardiac and respiratory disease Chairman: Professor J. O. Forfar Paediatric cardiology, by D. L. Gilday. Value of krypton 81m ventilation and 9 9Tc m macro-aggregate lung scans in children, by I. Gordon, G. Ciofetta and F. Fazio. The use of Xenon 133 for lung perfusion visualization in children with heart disease, by J. W. Haggith, H. H. Bain, J. D. Fenwick, A. S. Hunter and M. Heppell. Lung scanning in paediatric practice, by T. H. Macdonald, K. C. Young and P. Horton. The use of 8iKrm t o measure perfusion and ventilation distribution in children—quantitative aspects, by G. Ciofetta, J. M. B. Hughes and M. Silverman. VALUE OF KRYPTON 81m VENTILATION AND MACRO-AGGREGATE LUNG SCANS IN CHILDREN
PAEDIATRIC CARDIOLOGY
By D. L. Gilday
By I. Gordon, G. Ciofetta and F. Fazio
Division of Nuclear Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada The analysis of nuclear angiocardiography is divided into two parts. The first is visual inspection and assessment of the analogue images produced by the gamma camera. These images provide a useful pictorial demonstration of the flow of the bolus through the heart and lungs. The detection of a large left to right shunt is usually seen by this method. Other congenital anatomical defects can also be seen. The main method of analysis of the data regarding left to right shunting is via computer assessment of the timeactivity histogram of the transit through the lungs. The gamma variate analysis of the histogram has an excellent correlation with the Dye and Fick dilution methods (Treves and Malta 1974). The evaluation of right to left shunts can be carried out very effectively using the method described by Gates et al. (1971) which involved the injection of radioactively labelled microspheres of albumin which would impinge on the first vascular bed encountered. This resulted in a biological distribution of the tracer according to the output of the right ventricle. Thus, by quantifying the amount of activity within the lungs as compared with the whole body, one can get an estimate of the amount of blood going to the lungs and the amount of blood shunted. Of recent marked interest is the use of thallium 201 chloride in the evaluation of paediatric heart disease in the newborn. The differentiation of global ischaemia (transient myocardial ischaemia) is very important in that the patient may present as if there was congenital heart disease. The appearance in the thallium scan of minimal activity within the myocardium suggests this diagnosis. In addition the anomalous left coronary artery will cause a defect in the perfusion to the myocardium which is readily assessed. Infundibular hypertrophic subaortic stenosis and other cardiomyopathies are readily detected, diagnosed and differentiated one from another. With the addition of the multiple gated acquisition study one can also assess the overall function of the left ventricle at that time. REFERENCES TREVES, S., MALTZ, D. L., 1974. Radionuclide angiocardi-
ography. Postgraduate Medicine, 56, 99-107. GATES, G. F., ORME, H. W., DORE, E. K., 1971. Measure-
ment of cardiac shunting with technetium labelled albumin aggregates. Journal of Nuclear Medicine, 12, 746-749.
Hospital for Sick Children, Gt. Ormond Street, London WC1 3 TV and Hammersmith Hospital, Du Cane Road, London W12 OHS Krypton 81m has a \ life of 13 sec and is a pure y emitter at 190 KeV. It is eluted from a rubidium generator, the \ life of which is 4.5 hours. The latter is produced by a cyclotron. The child lies supine on the gamma camera and the rubidium generator is eluted with humidified air. An intravenous injection of 99Tm macro-aggregate are injected at the start of the examination. The patients examined fall into four main groups: (A). Establish the diagnosis. This is a relatively small group of patients in whom the combined ventilation/perfusion has either suggested the exact diagnosis or directed the attention of the clinician and diagnostic imager to the abnormal area where the diagnosis has been tentatively suggested. (B). The evaluation of surgical procedures on the pulmonary artery. This technique is valuable in assessing the post-operative patency of the relevant pulmonary artery and thereby the vascularization of the relevant lung. (C). Refute a diagnosis. A normal ventilation/perfusion scan in a child suspected of having either bronchiectasis or a foreign body is very strong evidence that there is no significant disease present. Both anterior and posterior oblique projections must be obtained as well as PA and lateral radiographs. Fluoroscopy is also essential in cases of suspected foreign body. (D) To establish the extent of the disease. Ventilation/perfusion scans are proving to be a very sensitive index of the extent of lung disease in children with chronic lung disease. In children with bronchiectasis who are not responding to adequate active medical therapy and in whom surgery is therefore contemplated, a high quality ventilation/perfusion scan with all four oblique projections may alleviate the need for bronchography. It is essential to combine the information from all modalities of diagnostic imaging step by step in order that the next relevant examination will be carried out. In an area where so many different modalities of investigation are available it is essential that problem-oriented paediatric imaging is practised.
Reprints of these abstracts may be obtained free from the Managing Editor, British Journal of Radiology, 32 Welbeck Street, London W1M 7PG (01-935 6867).
676
AUGUST 1979
Proceedings of The British Institute of Radiology THE USE OF XENON 133 FOR LUNG PERFUSION VISUALIZATION IN CHILDREN WITH HEART DISEASE
By J. W. Haggith, H. H. Bain, J. D. Fenwick, A. S. Hunter and M. Heppell Regional Medical Physics Department, Newcastle upon Tyne This preliminary study was to determine the relative pulmonary perfusion in 16 children with congenital heart disease. The technique involves an intravenous bolus injection of 133Xe in saline with the patient positioned supine over a gamma camera. No special preparation of the patient is required. Serial two-second posterior views of the lungs are obtained using a data-processing system. Timeactivity curves are created for each lung from which the relative lung perfusion may be determined. Right to left shunting can also be detected. These curves facilitated an estimate of the radiation dose. In these patients, for an administered activity of 0.2 /^Ci/kg body weight, the dose is not greater than 10 mrem whole body and 1 5 mrem to the lung mucosa. The technique has been used to demonstrate relative perfusion in patients with systemic arterial to pulmonary arterial anastomoses, with pulmonary stenosis and with pulmonary vascular disease. The method is safe and relatively non-invasive and may prove valuable in the long-term management of these patients.
the use of lung scans. Children who had radiotherapy for lung secondaries from solid tumours, e.g. Wilm's tumour, showed some reduction in distribution to the lung receiving radiotherapy. This reverted to normal after many months. In 33 children with scoliosis we have shown that the bias (the percentage by which the activity of the more active lung exceeds the less active) of perfusion and ventilation increases as the angle of curvature increases. Preliminary findings also suggest that perfusion is reduced in the concavity of the curve but this matter requires further investigation. In conclusion we would suggest that with the scintillation camera facilities available in most teaching hospitals, a clinician (in this case a paediatrician) can obtain information which is of relevance in the routine clinical care of patients.
THE USE OF 81Krm T O MEASURE PERFUSION AND VENTILATION DISTRIBUTION IN CHILDREN QUANTITATIVE ASPECTS
By G. Ciofetta*, J. M. B. Hughes and M. Silverman Royal Postgraduate Medical School, Hammersmith Hospital, London, W. 12
The continuous inhalation of 81 Kr m (tj 13 sec) allows images of lung ventilation to be recorded using a gamma camera (Fazio and Jones, 1975). Detection of regional ventilation defects is possible using this technique during normal breathing and therefore without the patient's co-operation and with minimal radiation exposure. LUNG SCANNING IN PAEDIATRIC PRACTICE Application of 8 1 Kr m ventilation studies in children is complicated by the very fast ventilatory turnover (V/VOL) T. H. Macdonald frequently found in neonates and infants. Under these conditions equilibrium between regional inspired and Royal Hospital for Sick Children, Glasgow expired isotope concentration may occur, despite the very rapid physical decay and the 81 Kr m images may reflect lung K. C. Young and P. Horton volume rather than ventilation distribution. Images recorded during continuous intravenous inDepartment of Clinical Physics and Bio-Engineering, Glasgow fusion of 8 1 Kr m dissolved in 5% dextrose, reflect lung Regional lung function studies are of value in paediatrics perfusion but are also affected by the distribution of ventiparticularly between 18 months and 5 years, a period when lation. This occurs because radioactive gas evolved into the standard lung function tests are rarely applicable. Since alveoli is removed by ventilatory washout (V/VOL) September 1976 we have performed almost one hundred (Ciofetta et al., 1978). It is possible to measure ventilatory lung scans in children aged six weeks to seven years. These washout (V/VOL) regionally in absolute units (1. min -1 . 1-1) 133 studies were performed using Xe. Ventilation and from the clearance curves of inhaled and infused 81 Kr m . perfusion studies were performed in the upright position This measurement allows a more accurate interpretation using a gamma camera linked to a data analysis facility. Lung of the 8 iKr m ventilation and perfusion images in infants and images were recorded at one second intervals, were displayed children. Some practical examples were presented to illuson a colour television screen, and analysed to determine trate the clinical use of this quantitative analysis. distribution indices and mean fractional turnover rates for the upper and lower zones of each lung. The distribution REFERENCES indices were helpful in identifying small lungs or lung areas FAZIO, F. and JONES, T., 1975. Assessment of regional with a reduced contribution to ventilation or perfusion, e.g. ventilation by continuous inhalation of radioactive bronchiectasis. In the latter case non-functioning lung tissue krypton-81m. British Medical Journal, 3, 673-676. could be removed. Reduction in distribution and of fracCIOFETTA, G., PRATT, T. A. and HUGHES, J. M. B., 1978. tional turnover was used to identify conditions such as the Comparison of krypton-81m and technetium-99m hypoplastic lung syndrome, and a pattern of ventilation and human serum albumin for measurement of pulmonary perfusion mismatching, together with reduced turnover perfusion distribution. In: Clinical and Experimental rates, to identify a diffuse emphysema in a very young Applications of Krypton-81m. British Journal of Radiinfant. In one patient, turnover in the perfusion study was ology, Special Report No. 15, 38-45. considerably prolonged when compared with the ventilation study. Biopsy demonstrated pulmonary eosinophilia. The abnormality in the perfusion study reverted to normal with *Present address: II Clinica Pediatrica, Universita degli corticosteroid therapy and treatment could be monitored by Studi, Roma, Italy.
677
VOL.
52, No. 620 Proceedings of The British Institute of Radiology
Urinary tract Chairman: Professor J. S. Robson Measurement of separate renal function with 197HgCl2, by C. Raynaud. Early detection of renal damage, by M. V. Merrick, W. S. Uttley and R. Wild. Direct radionuclide cystography, by A. R. Constable. A comparison of nuclear medicine and excretion urography in the follow-up of ileal loop diversion, by J. D. Orr, M. V. Merrick, R. Wild and I. S. Kirkland. on the RIK than on EU, in nine kidneys. These were segmented defects not associated with deformation of the perirenal fat. It is concluded that the RIK is more sensitive than EU By C. Raynaud for detecting segmented scars, but the EU is the better technique for the detection of concentric cortical loss. Service Hospitalier Frederic Joliot, Departement de Biologie, A technique of detecting vesico-ureteric reflux (VUR) at Commissariat a VEnergy Atomique, 91406 Orsay, France the end of the renal function examination using TcDTPA When radiomercury is injected in soluble form such as was described. The technique is comparable in sensitivity to 197 HgCl2, renal activity rises slowly to a plateau of 19 to the radiographic micturating cystourethrogram, but avoids 19-5% of the injected dose in the normal subject, within 24 the need for catheterization. hours. It remains at this level for several days. Uptake, generally measured at the second or the third day, depends on the functional activity of the renal parenchyma. It is increased if renal function is increased, and decreased if renal function is decreased. It is significantly correlated with DIRECT RADIONUCLIDE CYSTOGRAPHY inulin and PAH clearances, and Tm of PAH. The measurement is generally made by quantitative By A. R. Constable scintigraphy using a gamma camera or a rectilinear scanner. Two corrections are used, one for kidney depth, the other Institute of Urology, St. Pauls Hospital, Endell Street, for liver interference. Results calculated as a percentage of London, WC2 the injected dose are finally expressed as a percentage of normal, the normal values being 100±13% of normal mean During the normal course of diagnosis and treatment of for each kidney, and 100 ± 11 % of normal mean for global vesico-ureteric reflux (VUR), children will frequently be exposed to a considerable radiation dose from intravenous uptake. The Hg uptake test is useful to the urologist who needs urograms (IVU's) and micturating cystourethrograms a reliable measure of the functional state of each kidney, for (MCU's). Radionuclide cystography (RNC) normally results in a example in obstructive uropathies, where he must decide between conservative surgery and nephrectomy. It is also radiation dose about a hundred times smaller than the useful when evaluating the efficiency of medical or surgical corresponding radiographic procedure. The diagnostic therapy. It is especially useful when assessing compen- reliability of RNC has been shown to be similar to that of MCU and this, together with the favourable dosimetry, satory hypertrophy. The weakness of this technique is the radiation dose suggests that the technique should be included in the normal absorbed by the kidneys, which197amounts to 9 rad in young management protocol for these patients. Although the quest m for a completely atraumatic VUR investigation favours the children. Attempts to replace HgCl by "Tc -DMSA, 2 "Tc m -TMA, and radioactive bismuth were not successful, indirect RNC methods, the direct (per catheter) method is due to the lack of reproducibility with DMSA and TMA, generally thought more suitable for children and for patients with outflow abnormalities. and high urinary excretion of Bi. The results of a recent study comparing radiographic and If carefully controlled, by arteriography for example, the radionuclide techniques and the place of RNC in a suggested Hg uptake test temains extremely useful. protocol were discussed. MEASUREMENT OF SEPARATE RENAL FUNCTION WITH
EARLY DETECTION OF RENAL DAMAGE
By M. V. Merrick, W. Uttley and R. Wild Royal Hospital for Sick Children and Western General Hospital, Edinburgh Radioisotope imaging of the kidney (RIK) was compared with excretion urography (EU) in 79 children (155 kidneys) with urinary tract infections. Scans were performed not less than one hour after the intravenous administration of 75 yCi/kg of technetium dimercaptosuccinate. The standard radiographic technique of EU was modified as necessary by the radiologist performing the examination. Ninety-seven kidneys were considered normal by both techniques; in a further 46 both were abnormal, and showed a similar extent of renal cortical loss. There was a discrepancy in 12 cases. Cortical loss was present on the EU in three children with a normal RIK. In one case there was movement on the RIK. The other two had concentric cortical loss. Defects were present, and were more extensive
A COMPARISON OF NUCLEAR MEDICINE AND EXCRETION UROGRAPHY IN THE FOLLOW-UP OF ILEAL LOOP DIVERSION
By J. D. Orr, M. V. Merrick, R. Wild and I. S. Kirkland Departments of Surgical Paediatrics, Nuclear Medicine and Radiodiagnosis, University of Edinburgh, Western General Hospital, Edinburgh Progressive deterioration of the upper urinary tract occurs in many children who have undergone urinary diversion. Early detection of this deterioration is difficult as biochemical investigations give little indication of early damage, and although excretion urography gives adequate morphological detail of the kidney, it is not a satisfactory
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Proceedings of The British Institute of Radiology method of assessing renal function. It is hoped that more sophisticated radioisotope techniques might detect change at an early stage. A small group of 24 patients in whom the original indication for diversion had been myelomeningocoele were investigated, on average 12 years after operation. From this group 47 kidneys were available for study. The excretion urogram was carried out in a standard manner. The radioisotope investigations were performed using a gamma camera on line to a dedicated mini-computer. For the initial dynamic study "renograms" were obtained utilizing " T c m DTPA, and on the following day renal scans were obtained 2-4 hours after injection of Tc DMS. The results obtained from the differing techniques were then
compared. On initial comparison both techniques were found to be in concordance in 85% of the kidneys compared, but when the amount of information obtained from each investigation was considered, although found to be similar in 75%, in 17% the radioisotope methods gave more information. Overall the combined radioisotope technique gave more information concerning the morphology, total renal function and relative function of both kidneys, especially when renal function was poor. Scanning could be carried out at lower risk, lower radiation dose and lower cost. Therefore, it is considered a suitable method of follow-up in this group of patients. Where necessary further morphological information can always be obtained from the excretion urogram.
General topics Chairman: Dr. J. P. Lavender Bone imaging in paediatrics, by D. Gilday. Gastro-intestinal haemorrhage unrelated to gastric mucosa diagnosed on " T c m pertechnetate scans, by I. Gordon. BONE IMAGING IN PAEDIATRICS
By D. Gilday Division of Nuclear Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada Since the introduction of the phosphate compounds for bone imaging there has been a dramatic utilization of bone scans in paediatric diseases. In most benign diseases of bone the addition of immediate post-injection blood pool images has proven to be extremely valuable in assessing the degree of hyperaemia of the lesion. The use of high resolution and magnification pinhole views in the imaging of lesions, especially those which are avascular, is very important. The focal accumulation of bone radiopharmaceutical associated with the intra-osseus hyperaemia has proven to be a very reliable indicator of osteomyelitis and to separate the latter from cellulitis. The viability of bone after trauma can be readily assessed especially with magnification views. Skeletal pain in childhood is often a diagnostic dilemma, the cause of which can be both detected and characterized by bone imaging. This is especially so in the diagnosis of occult, axial skeleton osteoid osteomas. Although the detection of Legg-Perthes disease is usually made radiologically, in some instances the radiographs may be normal where the bone scan will demonstrate absent deposition of radiotracer in the femoral head, indicating the avascular nature of the disease. Re-vascularization of the femoral head can be readily assessed by the bone scan as it is a sensitive indicator of bone and blood flow.
Neoplasia, both primary and secondary, involving the skeleton can be better assessed by bone scanning using screening gamma camera images and selective high quality, high resolution or magnification images, rather than by radiological skeletal survey (especially in neuroblastoma, lymphoma, leukaemia and bone secondaries from osteogenic and E wing's sarcoma). There are some difficulties in the use of bone imaging in childhood such as the contamination of the skin with radioactive urine which must be prevented at all costs, and the involuntary voiding on the part of young children and infants which may lead to contamination of the clothes or pyjamas.
GASTRO-INTESTINAL HAEMORRHAGE UNRELATED TO GASTRIC MUCOSA DIAGNOSED ON 99 Tc m PERTECHNETATE SCANS By I. Gordon Hospital for Sick Children, London WC1 Small bowel bleeding due to an anastomotic ulcer in one patient and a haemangioma in another were diagnosed by " T c m pertechnetate radioisotope scans. Multiple views of the abdomen during the radioisotope scan proved essential. The rationale of this technique for imaging in cases of haemorrhage from the gastro-intestinal tract was described.
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