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R Itti

Publications and source records attributed to R Itti.

At least 19 recordsLinked to original sources
PubMed1992

Clinical experience with technetium-99m teboroxime scintigraphy in patients referred for myocardial perfusion evaluation.

A series of 30 patients (25 males, 5 females, age = 28-73 years) with a clinical indication of thallium-201 stress/4 hours redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium-99m teboroxime (CARDIOTEC, Squibb Diagnostics) in order to assess the clinical usefulness of this new molecule and to compare it to thallium. In all cases coronary artery disease was known or highly suspected, with a history of myocardial infarction in 18 cases (subacute n = 6, remote n = 12) and/or previous by-pass surgery or PTCA in 5 cases. Medical treatment was not discontinued at the time of stress testing. Coronary angiography was available for 27 patients. Exercise tests for both tracers were carried out on an ergometric bicycle during the same day and the levels of exercise achieved for the thallium studies were very similar to those achieved for teboroxime. Imaging was performed in three planar projections and sudies were evaluated using a model with 4 territories: septal and anterior assumed to correspond to the LAD artery, lateral and latero-posterior (= LCX), inferior and posterior (= RCA) and apex. Classification of results was: normal, ischemic, infarcted and infarcted with ischemia. With reference to the thallium-201 results, agreement was found in 86% (37/43) of normal regions and in 82% (63/77) of abnormal regions. Relative to documented coronary artery lesions (27 patients) sensitivity and specificity of thallium and teboroxime for exact correspondence between arteries and territories were, respectively: thallium, se = 71%, sp = 64%, teboroxime, se = 67%, sp = 75%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Technetium-99m teboroxime scintigraphy. Clinical experience in patients referred for myocardial perfusion evaluation.

In order to evaluate the clinical value of a new myocardial perfusion tracer, a series of 30 patients (25 male, 5 female, mean age 56 years) referred for thallium 201 stress/redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium 99m teboroxime (Cardiotec SQUIBB). In all cases coronary artery disease was known or highly probable, with a history of myocardial infarction in 18 cases. Medical treatment was not discontinued at the time of stress testing, and coronary angiography was available in 27 patients. Exercise tests for both tracers were carried out on a bicycle ergometer during the same day, and the levels of exercise achieved for the 201Tl study were very similar to those achieved for 99mTc-teboroxime. Studies performed in three planar projections were evaluated using a model with four territories: septal and anterior assumed to correspond to the left anterior descending artery, lateral and latero-posterior (left circonflex), inferior and posterior (right coronary artery) and apex. Classification of results was: normal, ischaemic, infarcted and infarcted with ischaemia. On comparison with the 201Tl results, agreement was found in 86% (37/43) of normal regions and in 82% (63/77) of abnormal regions. Relative to documented coronary artery lesions (27 patients), sensitivity and specificity of 201Tl and 99mTc-teboroxime for exact correspondence between arteries and territories were respectively: 201Tl: sensitivity 64%, specificity 60%; 99mTc-teboroxime: sensitivity 62%, specificity 77%.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1990

The potential usefulness of condensed image processing of sequential lymphoscintigrams in patients with lymphedema.

Condensed image processing (CIP), a computerized technique of scintiscans that generates a vertical distribution of activity as a function of time in a single image, was applied to isotopic lymphoscintigrams of four patients with leg lymphedema. By "condensing" information gained from multiple images into a single image, CIP better evaluates ascending progression of radiolabeled colloid in peripheral lymph and better localizes stagnant areas. In "high lymph flow failure," CIP also depicts radioactive "bursts" suggestive of increased lymphatic truncal contractility. This data processing method improves interpretation of dynamic scintiscan recordings and seems ideally suited for evaluation of peripheral lymph kinetics.

Adolescent↗
PubMed1989

[Significance of isotopes in the study of pre-excitation and ventricular tachycardia].

In normal patients, Mac Carthy has demonstrated that there was a very close correlation between the ventricular contractile activity, evaluated by Fourier's isotopic phase analysis, and electrical depolarization, evaluated by endocardial mapping. It has therefore been possible to study asynchronisms or asymmetries of the ventricular contraction-depolarization and particularly the syndromes of ventricular pre-excitation and ventricular tachycardias. In Wolff-Parkinson-White syndromes (WPW), the mapping obtained by heart cavity tomography in addition to dual-plane gamma-angiography, provides most useful informations, due to additional section planes permitting tridimensional location of the earliest site of ventricular activation. It is quite useful to locate the bundle of Kent always difficult on surface electrocardiogram, or when the endocardial exploration does not permit to precisely locate the site of the excentric atrial activation in case of multiple bundles of Kent or without retrograde conduction. When the left bundle of Kent is barely identified, the isotopic image may be improved by oesophageal stimulation. Additional parameters (use of several harmonics, factorial analysis) will permit to improve the localization of accessory pathways, to be destroyed by fulguration or surgery. In case of ventricular tachycardias with limited functional tolerance, only gamma-angiography, lasting only 3 to 5 minutes, may be used. Combined with endocardial tomography or even gamma-angiography performed in sinus rhythm, not only the site of origin of the ventricular ectopy may be localized, but it also can be correlated with ventricular kinetics abnormalities and the cardiopathy in question may be identified. Most authors consider that there is a close relationship between isotopic site, electrocardiographic appearance and the site found by endocardial mapping or "pace-mapping". In patients with ventricular tachycardias of different morphologies, isotopic mapping permits to differentiate those originating from a same lesion (which may be treated by surgery of fulguration) from those originating in remote areas. Therefore, this technique is a non aggressive and rapid method providing accurate informations on severe rhythm disorders currently treated by eradication of their anatomical substratum.

Electrocardiography↗
PubMed1989

Factorial analysis of dynamic lymphoscintigraphy in lower limb lymphoedema.

The purpose of this work is to assess the contribution of factor analysis to the interpretation of dynamic lymphoscintigraphy. Twenty six adult patients with a lower limb lymphoedema and five control patients were studied. The technique involved a 3 mCi lymphovectoscint* 99Tcm-labelled ammonium sulphur colloid, bilateral pedal subcutaneous injection. Recording consisted of 40 consecutive 1-min frames of both legs followed by static pictures of each leg and pelvis at 40 min and 4 h after injection. The analysis of static pictures allowed a classification of patients into three groups: enhanced pattern, hypoplasia and dermic reflux. To evaluate better the different kinetic components of the sequential pictures, a factorial analysis (FA) software package was used. FA processing enabled the extraction from the dynamic series of different dynamic components, factorial curves and their associated factorial images which represent the anatomic structures with the same temporal behaviour. In each pattern the results of dynamic recording and of three FA factors were compared. FA provides an analytical temporal and spatial description of the dynamic sequence by extracting the different kinetic components; it yields a better differentiation of vessel and interstitium activity. It also provides some clues towards the understanding of oedema physiopathology and is of potential interest for the management of lymphoedema.

Adolescent↗
PubMed1989

[Pharmacokinetics of intradermally-administered drugs].

The dermis, considered as a potential route of administration for drugs, has been widely and empirically used for more than a century. The comparative intravenous and intradermal administration of radiotracers makes it possible to demonstrate that the intradermal route has its own diffusion kinetics and its own biodistribution.

3-Iodobenzylguanidine↗
PubMed1988

Characterization of right or left ventricular contraction heterogeneity using Fourier phase analysis. Application to a group of patients with severe ventricular arrhythmias.

The standard deviation of the first harmonic Fourier phase histogram is an indicator of the contraction heterogeneity of the heart ventricles. This approach has been applied to analyse tomographic blood pool (99mTc) examinations in a group of 32 patients with angiographically verified mainly right (RV) but also left (LV) kinetic disorders in relation to severe ventricular arrhythmias and suspicion of arrhythmogenic right ventricular dysplasia (ARVD). The reference group consisted of ten patients with low probability of cardiac kinetic abnormalities. Thick tomographic slices including both ventricles have been reconstructed in the horizontal long axis orientation from a series of 32 gated projections recorded over a 360 degrees rotation. Separately for each ventricle the Fourier phase histograms have been computed and characterized by their standard deviations (PSD). Normal values (mean +/- standard deviation, LV = 11 degrees +/- 5 degrees, RV = 12 degrees +/- 5 degrees) were significantly lower (P less than 0.01 and P less than 0.001) than those measured in abnormal cases (LV = 19 degrees +/- 10 degrees and RV = 31 degrees +/- 17 degrees). Detailed analysis of the data supports the hypothesis of a primary RV disease in ARVD, with secondary LV extension. PSD seems to be a good predictor of an organic cardiac disease underlying ventricular arrhythmias and may be used for screening the patients.

Adult↗
PubMed1988

[Isotope angiocardiographic study of 30 cases of ventricular tachycardia with Fourier phase analysis].

Twenty-seven patients (15 men, 12 women; mean age 48.9 years) suffering from ventricular tachycardia (VT) (n = 30) were studied by radionuclide angiocardiography with Fourier phase analysis, both in sinus rhythm and during tachycardia. VT was spontaneous, electrically inducible, sustained, haemodynamically stable and monomorphous, with a mean rate of 174 beats/min (range: 115-260 beats). Heart diseases responsible for VT were: non-obstructive cardiomyopathy (n = 7), hypertrophic cardiomyopathy (n = 1), ischaemic heart disease (n = 5), probable right ventricular arrhythmogenic dysplasia (n = 4), congenital left ventricular aneurysm (n = 2), sequela of myocarditis (n = 2) and aortic valve regurgitation (n = 1); no heart disease was detectable in 5 patients. On surface electrocardiogram there was good concordance between the initial radionuclide site of VT activation and the configuration and electrical axis of QRS. At Fourier phase analysis all 17 VT of the right lag type originated in the left ventricle, arising from the apical septum (n = 7) or lateral segment (n = 2) in case of left axis, from the basal segment (n = 6) or the lateral segment (n = 1) in case of vertical or right axis, and from the middle left septum (n = 1) in case of normal axis. Nine VT of the left lag type originated in the right ventricle, arising from the basal septum or the latero-basal region in case of vertical or right axis (n = 6), from the apical septum or the inferior-apical region in case of left axis (n = 2) and from the middle septum in case of normal axis (n = 1). Four of our patients (3 with coronary disease and 1 with congenital left ventricular aneurysm) had VT of the left lag type and an initial radionuclide site of activation in the middle part of the left septum in case of left axis (n = 2) and in the basal part of that septum in case of right axis (n = 2). Seven patients were operated upon for recurrent VT: 4 had intra-operative mapping which in every case confirmed the results of radionuclide angiocardiography, a method which in the other 3 patients was the only surgeon's guide. Correlations between the site of origin of VT at radionuclide mapping and kinetic abnormalities visualized at radiological angiography and gamma-ray angiocardiography were common in our study. In one of our patients the same lesion gave birth to 2 VT of different morphologies.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1987

Visualization of the thoracic duct by lymphoscintigraphy.

Imaging of the thoracic duct is usually performed by radiological lymphography. However, this procedure, which uses an oil based dye injected directly into the lymph channels, has some adverse effects. In this paper we note that lymphoscintigraphy, a physiological and non invasive method, may visualize thoracic duct abnormalities, and might be particularly useful when radiological lymphography is contraindicated.

Chylothorax↗
PubMed1987

Oxygen transport to tissue modified by entrapment of an allosteric effector of haemoglobin in erythrocytes.

Oxygen affinity of haemoglobin is modulated by several parameters such as the allosteric effector 2-3 DPG for most mammalians. Inositol hexaphosphate (I.H.P.) exerts the same effect on haemoglobin. A previously developed new methodology for the entrapment of drugs into erythrocytes has been adapted to I.H.P.; it is based on a reversible osmotic shock. I.H.P. loaded red blood cells have characteristics very similar to those of native cells. The decrease in oxygen affinity is related to the dose of encapsulated I.H.P. In piglets, transfusion of such cells has led to an increase of oxygen extraction from haemoglobin. Normal anesthetized animals regulate their oxygen consumption by reduction of cardiac output.

2,3-Diphosphoglycerate↗
PubMed1987

[Comparative study of the effects of verapamil and propranolol therapy in 16 cases of obstructive hypertrophic myocardiopathy].

In a randomized, double-blind, cross-over study with plasma drug assays, 16 patients (11 men, 5 women; mean age 48.56 +/- 3.61 years) presenting with hypertrophic obstructive cardiomyopathy confirmed by echocardiography, left ventriculography and left intraventricular gradient measurement were treated with verapamil 480 mg/day or propranolol 320 mg/day. Both treatments produced functional improvement (p less than 0.01) which was more distinct with verapamil (NS). No changes in cardiothoracic index, echocardiographic parameters and Sokolow's index were observed. Mean total heart work during exercise, which was 1,197.27 +/- 135.89 watts before treatment, increased to 1,260.91 +/- 146.60 watts under propranolol (NS) and to 1,344.09 +/- 171.06 watts under verapamil (NS). Maximum heart rate during exercise, which was 162.3 +/- 3.46 beats/min before treatment, was reduced to a greater extent by propranolol (122.1 +/- 6.6 beats/min; p less than 0.001) than by verapamil (147.7 less than 5.08 beats/min; p +/- 0.01). The two treatments did not significantly modify ventricular arrhythmia, arterial and capillary pulmonary pressures, mean aortic pressure and left ventricular end-systolic pressure. Cardiac index, unchanged under verapamil, fell from 2.98 +/- 0.16 1 X min-1 X m-2 to 2.60 +/- 0.11 1 X min-1 X m-2 under propranolol (p less than 0.05). The left intraventricular gradient present in 5 patients at rest and during exercise, was reduced by both drugs. The gradient under isoprenaline (n = 16), which was 162.07 +/- 18.77 mmHg before treatment, fell to 93.86 +/- 24.48 mmHg with propranolol (p less than 0.05) and to 128.86 +/- 18.22 mmHg with verapamil (p less than 0.05). Left ventricular ejection fraction, mean circumferential fibre shortening speed and compliance coefficient remained unchanged under both drugs (NS). Left ventricular diastolic function, evaluated by radioisotope angiography in the last 9 patients, was most often improved by verapamil (NS). Verapamil was better tolerated generally and by the heart than propranolol. No correlation was observed between plasma verapamil levels and clinical results. Low plasma propranolol levels were often noted in non-responders, suggesting a need for treatment with high doses. It is concluded that at the dosage level used in this study propranolol and verapamil were equally effective, but there were individual variations in best response to one or the other of these two drugs.

Cardiomyopathy, Hypertrophic↗
PubMed1987

Use of lymphscintigraphy in traumatic chylous ascites.

This report describes the use of lymphscintigraphy in a patient with traumatic chylous ascites. Radioactivity "leakage" near the origin of the thoracic duct and accumulation into the peritoneal cavity were delineated.

Adult↗
PubMed1986

Symbolic reasoning about myocardial scintigrams in PROLOG.

PROLOG (PROgramming in LOGic) is the declarative programming language at the heart of the Japanese fifth-generation computer project. It is proposed that PROLOG is a suitable tool for symbolic image processing, once standard preprocessing has been done. In the present application, the problem of prediction of coronary anatomy from myocardial scintigrams is addressed. Uncertainty is dealt with by a combination of fuzzy-set theoretic and probabilistic reasoning. Heuristic classification rules are based on clinical experience and on a set of 247 myocardial scintigrams with their corresponding coronary angiograms.

Artificial Intelligence↗
PubMed1986

Scintigraphy in duodeno-gastric reflux: a new method of quantification.

A prospective study is undertaken in order to demonstrate the ability of scintigraphy with a non compartmental analysis to quantitate the duodeno-gastric reflux. 24 patients have been examined, sitting in front of a gamma camera: 12 with an endoscopically proved reflux and 12 normal subjects or volunteers. About 15 min after an injection of 148 to 222 MBq 99Tcm-IDA they were given a meal labelled with 37 MBq 113Inm-DTPA. Images were recorded for 2 h. Equal size gastric and duodenal ROIs were selected over the duodenum and stomach, avoiding overlap with neighbouring organs. The reflux index based upon the occupancy principle is calculated from the gastric and duodenal curves. It is the ratio between the gastric and duodenal ROI IDA fluxes. The value of the reflux index is 3 +/- 1.8% in normal subjects and 45 +/- 33% in pathological cases. Our method, which does not require intubation, quantitatively evaluates biliary reflux independently of injected dose and hepatic or gallbladder function.

Adult↗
PubMed1986

[Gamma-angiography during exercise in chronic aortic insufficiency. Development of ventricular function and regurgitation].

Twenty-three patients with chronic aortic incompetence (17 men and 6 women) aged 27 to 71 years (average 51 years) underwent sequential gamma-angiography at rest and during the different levels of exercise and recovery phase to investigate the evolution of ventricular function and regurgitant fraction and so, guide therapy. The radionuclide indices of left ventricular function (end diastolic and end systolic indexed volumes, global ejection fraction, regional wall motion) and the regurgitant fractions were calculated and compared with clinical, echocardiographic, angiographic and haemodynamic data. The changes observed on effort during gamma-angiography allowed identification of 3 groups of patients: Group I: compensated aortic incompetence with a normal left ventricular ejection fraction (0.69 +/- 0.1), a moderate regurgitant fraction (40 per cent +/- 20 per cent) and, during exercise, a stable left ventricular end diastolic volume index (less than 5 per cent variation), an end systolic volume index which decreased (average-13 per cent), an ejection fraction which increases (by more than 0.05 in 62.5 per cent of cases) and with good global and regional wall motion. Group II: intermediate cases with a left ventricular ejection fraction of 0.62 +/- 0.09 and a regurgitant fraction of 60 +/- 16 per cent. Individual variations were observed with this group which either resembled those of Group I or those of Group III.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Discriminant analysis of thallium-201 myocardial scintigrams.

In a group of 207 patients undergoing coronary angiography, myocardial scintigrams have been performed at rest (n = 95), after exercise testing (n = 50) or after dipyridamole vasodilation (n = 62). Pictures recorded in anterior and 45 degrees left anterior oblique projections have been analysed according to a model which divides each projection into 5 territories. Thallium uptake has been visually assessed using a three grade scale: 0 = normal uptake, + = sightly abnormal uptake, ++ = evident hypoactivity. With reference to angiography, sensitivity and specificity for prediction of coronary artery disease have been calculated in a classical way using three different criteria of positivity of increasing severity, and by a computerized method based on discriminant analysis. In the first case, sensitivity and specificity were highly dependent one on the other and, as could be expected, varied in opposite directions, a high sensitivity (89 to 100%) being only achieved by accepting a lack of specificity (33 to 57%). Discriminant analysis, on the contrary, provided for each type of protocol: rest, stress, dipyridamole and redistribution, a single optimized combination of sensitivity (74 to 87%) and specificity (92 to 100%). The corresponding point, when located on the receiver operating characteristics (ROC) diagram, demonstrated a clear improvement in diagnostic accuracy. The same method has been applied for discrimination, not only between normals and abnormals, but also between normals and patients with and without myocardial infarction (correct diagnosis in 50 to 68% of cases), and between normals and patients with single-, double- or triple-vessel disease (correct diagnosis in 17 to 65% of cases) with a high specificity (correct classification of normals in 86 to 100% of cases).

Coronary Angiography↗