OSPEDALE MAGGIORE C. A. PIZZARDI, BOLOGNA SERVIZIO DI MEDICINA NUCLEARE* (Primario: Prof. A. Am3ATI) SERVIZIO DI FISICA SANITARIA** (Direttore: Dr. A. RossI) CLINICA MEDICA DELL'OSPEDALE POLICLINICO S. ORSOLA, BOLOGNA CENTRO ANTIREUMATICO*** (Direttore: Prof. G. SOTGIU) DIAGNOSTIC VALUE OF COMPUTER-ASSISTED QUANTITATIVE RADIOISOTOPE ANGIOCARDIOGRAPHY ACHILLE ABBATI*
ANTONIO ROSSI** GIUSEPPE GUIDARELLI**
ANNA T. FAGGIONI***
In the last five years the availability of gamma-cameras, in conjunction with computers and 9°mTc-labelled albumin, has made possible a more extensive use of venous angiocardiography with radioisotopes, associated with the analysis of the passage of the radioactive bolus through the cardiac cavities, the lungs and the large vessels 1-24 Safety, the feasibility of control, and the ability to use this technique also in outpatients induced us to utilize it in patients with congenital, rheumatic, and atheromatous heart diseases, who were examined at regular intervals at our cardiographic units. Our aim was to obtain morphological information on the cardiovascular cavities and pathological changes in these and to study the passage of the radioactive bolus through these cavities and the lungs. The procedure we adopted, already described at the l l t h Symposium at Bad Gastein 1 and at the First World Congress of Nuclear Medicine at Tokyo 2 was as follows: 5-10 mCi of WmTc-labelled serum albumin with high specific activity were rapidly injected into the right jugular vein. Pictures were taken every 0.25 sec for 30 sec with a radicamera-60 equipped with a parallel-hole collimator and were recorded on magnetic disc by the computer system Med-II. Activity/time curves were then obtained for the various regions of interest (right superior vena cava, right atrium and ventricle, pulmonary artery, right and left lung, left atrium, when possible, and left ventricle, ascending and descending aorta, and the whole cardiac area defined by means of the light-pen): their numbering indicates the progression of the radioactive bolus as seen in the sequence of pictures. Key-words: Activity~time curves; Computer; Computer-assisted angiocardiography; Gamma-camera; Heart diseases; Radioisotope angiocardiography; ;~mTc-labelled albumin.
Received, December 6, 1974. La Ricerca Clin. Lab. 5, 169, 1975. 169
COMPUTER-ASSISTED ANGIOCARDIOGRAPHY
For a correct identification of the individual cardiac cavities, which is diNcult in many topographical heart conditions and in congenital heart defects, the images were condensed into 4 groups corresponding, respectively, to the right, pulmonary and left phases of the angiocardiography. In the 4th group the frames of the right and left phases were condensed. A computer programme in NUTRAN was prepared to enable the Med-II system to provide a rapid and automatic presentation of the transit curves for clinical use. An account of this programme has been given in previous reports 6.9, 10. 2o After 10-30 min a conventional photoscan of the heart was carried out with an E1 Scint digital scanner, connected with the coloured video unit (VDP2), to study the isocount areas and obtain the best morphological pictures of the cardiac cavities. CASE REPORTS So far we have used this method to examine 78 patients: 43 with congenital heart disease, 15 with valvular heart disease of rheumatic origin, 7 with atheromatous heart disease with hypertension, and 13 without any special findings in the cardiovascular system except for functional systolic murmurs. To give examples of the possibilities of this method we present the results obtained in some cases from each group, reporting the aspects of major physiopathologicaland clinical interest in the captions. The records usually sent to the cardiographic units for clinical use consisted of: a) serial scintiphotos of the cardiac cavities and lungs; b) areas of interest on condensed frames and activity/time curves from each of such areas, numbered according to the progress of the radioactive bolus, and finally the whole cardiac area; c) conventional photoscans of the cardiovascular cavities and the isocount areas obtained with the VDP2. DISCUSSION AND CONCLUSIONS The examples given from normal, congenital, rheumatic and atheromatous patients enable a preliminary evaluation of this technique to be made: it offers, as has been demonstrated, a dynamic representation of the first passage of the radioactive bolus through the cardiac cavities, which are identified by playing back the individual frames that have been recorded and condensed into groups corresponding to the right and left cardiac cavities and the lungs. In this way it is possible to obtain pictures of the cardiac cavities at their dearest, and that are thus better than the usual serial scintiphotos, although with not such good resolution as in X-angiocardiography. A physical ]actor which must be considered in the quantitative angiocardiography is the dead time of the system, that is the minimal average time which must elapse between two events so that they can be clearly distinguished from each other. Tests are being carried out on the method of correction proposed by ADAMS et al. 3, which can be easily computerized. Correct topographical delimitation of the individual heart cavities is necessary to obtain good activity/time curves: a complication is the frequent overlapping of some of these, as for instance the pulmonary artery by the left atrium, the aortic arch by the pulmonary artery, part of the right ventricle by the left ventricle: in each of the cases which we have given, it was possible to delimit the right atrial and ventricular areas free from activity arising from other superimposed cavities. However, analysis of the times of the peaks of curves of those areas and of the curve obtained from the whole heart area is very useful in interpreting the doubtful cases and understanding the haemodynamic significance of the double peaks. 170
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ANTONIO ROSSI** GIUSEPPE GUIDARELLI**
ANNA T. FAGGIONI***
In the last five years the availability of gamma-cameras, in conjunction with computers and 9°mTc-labelled albumin, has made possible a more extensive use of venous angiocardiography with radioisotopes, associated with the analysis of the passage of the radioactive bolus through the cardiac cavities, the lungs and the large vessels 1-24 Safety, the feasibility of control, and the ability to use this technique also in outpatients induced us to utilize it in patients with congenital, rheumatic, and atheromatous heart diseases, who were examined at regular intervals at our cardiographic units. Our aim was to obtain morphological information on the cardiovascular cavities and pathological changes in these and to study the passage of the radioactive bolus through these cavities and the lungs. The procedure we adopted, already described at the l l t h Symposium at Bad Gastein 1 and at the First World Congress of Nuclear Medicine at Tokyo 2 was as follows: 5-10 mCi of WmTc-labelled serum albumin with high specific activity were rapidly injected into the right jugular vein. Pictures were taken every 0.25 sec for 30 sec with a radicamera-60 equipped with a parallel-hole collimator and were recorded on magnetic disc by the computer system Med-II. Activity/time curves were then obtained for the various regions of interest (right superior vena cava, right atrium and ventricle, pulmonary artery, right and left lung, left atrium, when possible, and left ventricle, ascending and descending aorta, and the whole cardiac area defined by means of the light-pen): their numbering indicates the progression of the radioactive bolus as seen in the sequence of pictures. Key-words: Activity~time curves; Computer; Computer-assisted angiocardiography; Gamma-camera; Heart diseases; Radioisotope angiocardiography; ;~mTc-labelled albumin.
Received, December 6, 1974. La Ricerca Clin. Lab. 5, 169, 1975. 169
COMPUTER-ASSISTED ANGIOCARDIOGRAPHY
For a correct identification of the individual cardiac cavities, which is diNcult in many topographical heart conditions and in congenital heart defects, the images were condensed into 4 groups corresponding, respectively, to the right, pulmonary and left phases of the angiocardiography. In the 4th group the frames of the right and left phases were condensed. A computer programme in NUTRAN was prepared to enable the Med-II system to provide a rapid and automatic presentation of the transit curves for clinical use. An account of this programme has been given in previous reports 6.9, 10. 2o After 10-30 min a conventional photoscan of the heart was carried out with an E1 Scint digital scanner, connected with the coloured video unit (VDP2), to study the isocount areas and obtain the best morphological pictures of the cardiac cavities. CASE REPORTS So far we have used this method to examine 78 patients: 43 with congenital heart disease, 15 with valvular heart disease of rheumatic origin, 7 with atheromatous heart disease with hypertension, and 13 without any special findings in the cardiovascular system except for functional systolic murmurs. To give examples of the possibilities of this method we present the results obtained in some cases from each group, reporting the aspects of major physiopathologicaland clinical interest in the captions. The records usually sent to the cardiographic units for clinical use consisted of: a) serial scintiphotos of the cardiac cavities and lungs; b) areas of interest on condensed frames and activity/time curves from each of such areas, numbered according to the progress of the radioactive bolus, and finally the whole cardiac area; c) conventional photoscans of the cardiovascular cavities and the isocount areas obtained with the VDP2. DISCUSSION AND CONCLUSIONS The examples given from normal, congenital, rheumatic and atheromatous patients enable a preliminary evaluation of this technique to be made: it offers, as has been demonstrated, a dynamic representation of the first passage of the radioactive bolus through the cardiac cavities, which are identified by playing back the individual frames that have been recorded and condensed into groups corresponding to the right and left cardiac cavities and the lungs. In this way it is possible to obtain pictures of the cardiac cavities at their dearest, and that are thus better than the usual serial scintiphotos, although with not such good resolution as in X-angiocardiography. A physical ]actor which must be considered in the quantitative angiocardiography is the dead time of the system, that is the minimal average time which must elapse between two events so that they can be clearly distinguished from each other. Tests are being carried out on the method of correction proposed by ADAMS et al. 3, which can be easily computerized. Correct topographical delimitation of the individual heart cavities is necessary to obtain good activity/time curves: a complication is the frequent overlapping of some of these, as for instance the pulmonary artery by the left atrium, the aortic arch by the pulmonary artery, part of the right ventricle by the left ventricle: in each of the cases which we have given, it was possible to delimit the right atrial and ventricular areas free from activity arising from other superimposed cavities. However, analysis of the times of the peaks of curves of those areas and of the curve obtained from the whole heart area is very useful in interpreting the doubtful cases and understanding the haemodynamic significance of the double peaks. 170
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