[Bone angioscintigraphy in reflex sympathetic algodystrophies].
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Biomedical subjects
Publications and source records attributed to C Hocquard.
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Two types of radioisotope tomography have been developed: single photon emission computed tomography and positron emission tomography. Tomography of the heart meets with several problems due to the mobility and obliquity of that organ and to the heterogeneity of surrounding tissues. Compared with planar tomography, myocardial tomography with thallium 201 improves the detection of ischaemic and sub-ischaemic areas in myocardial infarction and chronic coronary disease. In spite of some technical limitations, tomography with labelled red cells is very helpful to determine pre-operative size and location of aneurysms.
Very few studies have been described comparing the value of exercise myocardial scintigraphy and left ventricular angioscintigraphy. The authors designed a study comparing these two investigations with conventional exercise stress testing and coronary angiography. The isotopic investigations were carried out within 48 hours of coronary angiography. A total of 143 patients undergoing coronary angiography (35 normal, 108 coronary patients: 36 single vessel, 36 double vessel and 36 triple vessel disease) were included in this study. The lesions were located of the LAD (77 cases), left circumflex (77 cases) and right coronary arteries (62). The sensitivity and specificity of both radionuclide investigations were evaluated to assess their diagnostic value; the best results were obtained with myocardial scintigraphy (sensitivity 86 p. 100; specificity 100 p. 100); angioscintigraphy had a sensitivity of 71 p. 100 and specificity of 97 p. 100, and conventional exercise stress testing of 42 p. 100 and 70 p. 100 respectively. The sensitivity seemed to increase with the degree of stenosis; although the sensitivity of myocardial scintigraphy increased progressively, that of angioscintigraphy doubled in cases of stenosis 90 p. 100 (stenosis less than 90 p. 100, sensitivity = 37 p. 100; stenosis greater than 90 p. 100, sensitivity = 73 p. 100). The sensitivity of myocardial scintigraphy with respect to the severity of the coronary artery disease was best in cases of right coronary artery stenosis (sensitivity in cases of RCA stenosis = 74 p. 100; sensitivity in LAD stenosis = 58 p. 100; sensitivity in left circumflex stenosis = 43 p. 100). The sensitivity of left ventricular angioscintigraphy was best in LAD stenosis (RCA stenosis = 50 p. 100, LAD stenosis = 64 p. 100, left circumflex stenosis = 36 p. 100). The sensitivity of both investigations was poor in left circumflex artery stenosis even when severely diseased. The sensitivity of both investigations was better in diffuse coronary artery disease: myocardial scintigraphy (single vessel disease: 72 p. 100, double vessel disease: 92 p. 100, triple vessel disease: 94 p. 100), left ventricular angioscintigraphy (61 p. 100, 69 p. 100, and 83 p. 100 respectively). Although the association of these two radioisotopic investigations does not improve diagnostic sensitivity, it does provide more information about the localisation and extension of the coronary artery disease especially in LAD and right coronary artery stenosis. These results suggest that these investigations are complementary in the evaluation of patients with coronary artery disease.(ABSTRACT TRUNCATED AT 400 WORDS)
Classical bone scintigraphy can be completed by a dynamic study of the blood supply of a previously defined anatomical region. Our protocol consists of the recording of early images in the histogram mode, centred on the selected pathological region and on the symmetrical region which acts as a control. One film is taken every 3 seconds for 3 minutes following an intravenous injection of 20 mci of Tc99m MDP into a cubital fossa vein. More limited symmetrical zones of interest are visualised on the image obtained by summation of all of the information obtained during the second minute following the arterial passage of the radioactive bolus. The curve reflecting the variation in activity for each zone of interest over these three minutes can therefore be obtained. The first part of the curve, until the first slope change, corresponds to the arterial phase (blood flow), the second part, which includes a brief venous phase, corresponds to the vasculo-tissue phase (blood pool). The value of these bone image, which allow a very detailed analysis of the topography and intensity of the uptake, is above all diagnostic, while the early, vascular images and the resulting curves are essentially of pathophysiological interest. Bone angioscintigraphy is a triple examination and one of its best applications is in reflex sympathetic dystrophy. It is able to distinguish very objectively between "hot" and "cold" forms and it can indicate the most appropriate treatment for each case and follow the effects of treatment. The other indications for bone angioscintigraphy also include Paget's disease, especially the monitoring of treatment, osteomyelitis, sarcomas and osteonecrosis.
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25 patients (2 normal and 23 coronary artery disease) were studied by 99m Tc gated blood pool scans at rest, with right atrial pacing, right atrial pacing and nitroglycerine, and finally nitroglycerine alone. Total and regional ejection fractions were measured and the induced and reversible asynergy with right atrial pacing and nitroglycerine was also assessed.
The bone fixation of diphosphonates depends on the degree of osteogenesis, the blood bone flow and the capillary permeability. The precise characteristics of the fixation kinetic are not very well known. The authors propose a new method which makes possible to study them and expose their results. For average persons the fixation curves present an ascending line, an apex, reach within 40 mn and a descending line. Any affection don't seem to have characteristic curves; on the contrary it is possible to have different curves for a same affection which implies doubtless various anatomic and metabolic data.
In the left ventricle, isotope techniques can be used to study the perfusion of the myocardium or the ventricular function. Because of the thinness of the walls of the right heart, the classical examinations and Thallium 201 perfusion cannot be used to demonstrate a disorder of perfusion in the right ventricle. Nevertheless, it is possible, with the aid of Technetium 99m labeled pyrophosphate, to diagnose and localise necrosis of the inferior wall with an acceptable degree of sensitivity, during the acute phase of the infarction. However, the major value of isotope techniques is to evaluate right ventricular function by determining the value of the global ejection fraction and the kinetic anomalies of the different walls. These methods, together with echocardiography, allow the diagnosis of lesions of the inferior part of the right ventricle in patients with inferior necrosis... Furthermore, because these methods allow quantification and because they are reproducible and repeatable, they can be used to follow the course of the right ventricular function in response to treatment.