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Biomedical subjects

R Itti

Publications and source records attributed to R Itti.

At least 37 records · Page 2Linked to original sources
PubMed1985

[Complex ventricular arrhythmia in apparently healthy young subjects].

The aim of this study of 20 young subjects (28 +/- 10.6 years) with no apparent cardiac disease on clinical examination and chest X-ray was to determine the origin of complex ventricular arrhythmias: monomorphic or polymorphic ventricular extrasystoles, isolated or in valves (average 18 158 +/- 12 388 per 24 hours) and/or ventricular tachycardia (5 cases, sustained in 3). These arrhythmias were aggravated (N = 6), disappeared (N = 8) or remained unchanged (N = 5) during exercise. The inter-critical ECG showed ST changes in 5 cases. The extrasystoles had a left bundle branch block configuration in 14 cases and a right bundle branch block configuration in 9 cases. Nine patients were Grade 2 (45%) and 11 patients Grade 4B of Lown's classification. Complementary investigations (echocardiography), radionuclide investigations, right and left heart catheterisation, selective right and left ventriculography and coronary angiography) showed a high incidence of arrhythmogenic right ventricular dysplasia (N - 14) associated with left ventricular abnormalities in 13 cases: hypofixation of Thallium (N = 14) associated with left ventricular abnormalities in 13 cases: hypofixation of Thallium (N = 11), abnormal global left ventricular function (N = 13) with decreased ejection fractions in half the cases, left ventricular dilatation in a third of cases (average and diastolic volume: 109.8 ml/m2), mean velocity of circumferential fibre shortening decreased in 86% of cases (average 0.88 cir/sec), angiographic abnormalities of segmental left ventricular wall motion in 36% of cases; 2 clinically silent cases of mitral valve prolapse were associated with these left ventricular changes; these cases represent forms of arrhythmogenic cardiac disease localised to the right ventricle or involving both ventricles which should be searched for routinely in young patients with apparently normal hearts but with idiopathic and severe ventricular arrhythmias. The diagnosis can only be established by angiography. In other cases, isolated left ventricular abnormalities are detected: two cases of hypertrophic non obstructive cardiomyopathy including one apical form, a condition which may be suspected from analysis of the surface ECG and careful 2D echocardiographic study; phonomechanography may be normal; one idiopathic left ventricular aneurysm which was only diagnosed at ventriculography; one dilated cardiomyopathy affecting the left ventricle. In our series, none of the patients had coronary artery disease and two patients even had no abnormality of any of these investigations.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

[Value of scintigraphy in the localization of digestive hemorrhage].

Scintigram imaging is a new means of localization of digestive tract hemorrhage, the radiopharmaceutic agent (technetium-labelled colloidal sulfur or technetium-labelled erythrocytes) accumulating at the bleeding site. The technique used consists of early recording over 80 minutes and then later serial imaging over 24 hours after radioisotope injection. The limitations and advantages of radioisotope investigations are discussed in relation to results in 6 patients with digestive hemorrhage explored by scintigraphy. When technetium-labelled erythrocytes are used the method is a non-invasive, simple and sensitive one for locating site of bleeding during the period of active hemorrhage. It appears to be complementary to arteriography, a more aggressive and less sensitive procedure, and to endoscopy, which explores small intestine and cecum with difficulty and cannot always determine the origin of the bleeding when other lesions exist. Experimental studies in the dog have shown that scintigraphy can detect digestive bleeding of about 0.1 to 0.2 ml/min, and this method of exploration should be used routinely when endoscopy and/or arteriography have not been performed or have given inconclusive results.

Aged↗
PubMed1985

[Cardiac radioisotopic tomography].

In addition to positron tomography, which involves the use of radioactive elements of physiological or pathological significance, there is another technic available, that of gamma emission tomography, which makes use of conventional tracer elements, and which therefore has important clinical applications which complete plane projection imaging. This method can be used both to investigate myocardial blood supply, using thallium 201 and to evaluate cardiac kinetics--of both the right and left ventricles--after labeling of the blood flow with technetium 99m.

Heart↗
PubMed1985

[Lymphoscintigraphy. A predictive test of post-traumatic lymphedema of the lower limbs].

Post-traumatic oedema after fractures of the tibia results from several causes which are often associated together. In addition to venous thrombosis, the lymphatic origin of oedema is not inconsiderable. Lymphatic scintigraphy was performed in 32 patients with tibial fractures, either open or closed. All were fixed internally. All had preventive treatment of venous thrombosis by calciparin. The intact leg was also investigated by scintigraphy which was done two to ten days after the trauma. The possible anomalies of scintigraphy are described and discussed. The patients were divided into two groups. Group one developed oedema at three months and group two did not. The anomalies of scintigraphy were significantly higher in group one. It is concluded that early scintigraphy is a safe test for the prediction of residual oedema after tibial fractures. The possible early prevention of oedema of a lymphatic origin is discussed.

Adult↗
PubMed1984

[Sympathetic paraganglioma. Scintigraphic detection using a new labeled molecule, meta-iodobenzylguanidine].

Two cases of sympathetic paraganglioma are reported: one, benign, in a 20-years old woman with arterial hypertension and attacks of excessive sweating; the other, malignant and with bone metastases, in a 44-years old woman. Both were diagnosed by scintigraphy, using meta-iodobenzylguanidine as radionuclide. This new radiopharmaceutic agent has recently been introduced for the detection of phaeochromocytomas, but it seems to be a general tissue marker of catecholamine uptake and storage. Its use as a therapeutic compound may also be envisaged.

3-Iodobenzylguanidine↗
PubMed1984

Phase quadrature shift between left and right ventricles during a ventricular tachycardia attack.

Equilibrium gated nuclear angiography was performed on a patient during an attack of ventricular tachycardia and then after conversion to sinus rhythm. Global and regional wall motion was assessed by means of isocontours, Fourier phase analysis and factor analysis. Ventricular phase histograms showed a 100 degrees difference between ventricles: left ventricular filling time occurred during right ventricular contraction. The earliest phase was located in the septum and the sequence of activation showed a large delay of left ventricular activation. After conversion to sinus rhythm, a right bundle branch block was observed, being almost the inverse of the latter situation.

Adult↗
PubMed1984

Meta-iodobenzylguanidine adrenal medulla localization: autoradiographic and pharmacologic studies.

In order to investigate the mechanism of uptake of meta-iodobenzylguanidine (mIBG) by the adrenal glands, autoradiographic and pharmacologic studies were performed in mice and dogs receiving radioiodinated mIBG. In mice, on macroautoradiography of whole body sections 48 h after 125I-mIBG, most of the radioactivity was focused in the adrenal glands. On microautoradiography, silver grains were exclusively located in the adrenal medulla. Tissue counting after phenoxybenzamine, cocaine, and desipramine treatment resulted in 45%, 35%, and 0% inhibition of mIBG uptake, respectively. Tissue counting and scintigraphic studies demonstrated a more than 50% mIBG release from the adrenal glands after reserpine. These data indicate the high affinity of mIBG for adrenal medulla and suggest that the mIBG and catecholamine uptake mechanisms are only partially the same.

3-Iodobenzylguanidine↗
PubMed1984

[Radioisotopic tomography in the study of cardiac function].

Dynamic tomographic images of the heart may be obtained by computerised treatment of a number of projections and planes recorded by a gamma camera rotating around a patient whose blood is labelled with radioactive technetium. This new technique of assessing cardiac function was tested in a group of 40 coronary patients and the results compared with standard contrast angiography. The following parameters were compared : LV volume, global and regional ejection fractions. The zones of interest were easily defined on the tomographic images and correction for background noise was negligible. Two different methods have been developed to measure volume. The first consists in counting the matrix units in three dimensions on serial planes through a given cavity. The second is based on the reconstruction of thick slices integrating all the ventricular radioactivity, the counting of which is calibrated with reference to an orthogonal plane. The correlations with angiography were excellent with both methods (R = 0,85 and 0,87 respectively). An equally good correlation was observed for ejection fraction (r = 0,85). A segmental model acceptable for both gamma line angiography, gamma tomography and contrast angiography comprises 6 segments : septal, apical, antero-lateral, postero-lateral, posterior, and inferior. The sensitivity and specificity of both isotopic methods of detection of major wall abnormalities (akinesia and dyskinesia) were assessed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Radioisotopic quantification of isolated mitral insufficiency].

A group of 23 consecutive patients with isolated mitral regurgitation confirmed by angiography, 8 of whom had normal and 15 abnormal coronary arteriographies, were compared with a control group of 27 subjects without valvular heart disease (normal coronary arteriography in 7 cases, abnormal coronary arteriography in 20 cases). After injection of technetium 99m labelled albumin, gamma-angiocardiography was performed in the left anterior oblique plane at equilibrium with electrocardiographic synchronisation. Fourier's analysis of the images excluded hepatic pulsation and dephasing of the two ventricles: amplitude images were used to trace the right and left ventricular zones of interest. The ratio of right to left ventricular ejection fraction was calculated in these zones from the radioactive count at end diastole and end systole. The ratio of the ejection fractions was 1.15 +/- 0.18 in subjects without valvular disease compared to 2.66 +/- 0.47 in patients with mitral regurgitation and normal coronary arteries, and 2.50 +/- 1.28 in mitral regurgitation with coronary artery disease (no significant difference between these two sub-groups). When compared with angiographic quantification of the mitral regurgitation, the ratio of ejection fractions increased progressively with the severity of the leak: 1.81 +/- 0.44 for grade I (9 cases), 2.37 +/- 0.80 for grade 2 (5 cases), 3.02 +/- 1.07 for grade 3 (4 cases) and 3.73 +/- 1.50 for grade 4 (5 cases). The differences between each sub-group are not statistically significant because of the small number of patients in each sub-group but all the values are significantly higher than the reference values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Beat-to-beat assessment of left ventricular ejection in atrial fibrillation.

Beat-to-beat left ventricular ejection was evaluated in a group of 20 patients with chronic atrial fibrillation using a computerized single probe detector. The reference group consisted of 10 patients with sinus rhythm. For each patient 30 successive cardiac cycles were analyzed and the relative variations of four parameters were assessed: R-R interval, diastolic and systolic time intervals, and ejection amplitude, corresponding to the left ventricular stroke volume. The mean variations were respectively 3.4%, 10.4%, 8.4%, and 11.8% in patients with sinus rhythm, and 21.9%, 37.9%, 10.6% and 30.5% in patients with atrial fibrillation. This demonstrates that changes in ejection are mainly related to the duration of the filling phase, with nearly constant systolic times. Correlations between R-R intervals and systolic ejection amplitudes were highly significant (P less than 0.001) in patients with atrial fibrillation in 85% of cases. This information complements the average ejection fraction obtained from multiple cycle superimposition.

Adult↗
PubMed1983

Negative lung thallium-201 uptake in right ventricular infarction.

In a case of right ventricular infarction, a negative lung image was observed on the resting thallium-201 scan, with a pulmonary activity much lower than the surrounding background. The myocardial image showed only a moderate inferior hypoactivity and the left ventricular ejection fraction was normal. This seems to be related to right ventricular failure with normal left ventricular function. It represents the opposite mechanism to the increased pulmonary thallium uptake commonly seen in severe left ventricular impairment.

Aged↗
PubMed1982

Determination of organ volume by single-photon emission tomography.

A method for estimation of organ volume is proposed, based on analysis of individual slices obtained from SPET images. In a phantom simulating clinical circumstances, the data show that the level a threshold at 46% of the maximum activity predicts most closely the true volume over a wide range above one liter. The level at 45% predicted better volumes of less than one liter. For phantoms of 839 ml or less, the error was 6.3 ml (one standard error of estimation). This level seems to be independent of the plane or position of the phantom and also independent of the amount of scattering material around it. Nonradioactive voids ("holes") within a phantom may be included or excluded at will when their edges are not tangent to the edge of the phantom. In such cases, their edges are not distinguishable from the edge of the phantom and their volumes are excluded. Knowledge of organ volumes has both diagnostic and therapeutic importance and could lead to a more precisely quantitated total of the radioactivity contained in an organ or space.

Models, Structural↗
PubMed1981

[Initial results of dynamic gamma-tomography of heat cavities].

After blood pool labeling using technetium albumin, 32 scintigraphic projections are recorded by means of a rotating gamma-camera. An electrocardiographic multi-gating acquisition procedure selects the dynamic pictures during the cardiac cycle of the patient. The computer processing of this set of data and the reconstruction of multiple tomographic slices through the thorax allow a precise kinetic analysis of the cardiac walls.

Electrocardiography↗
PubMed1980

[Study of dynamics and left ventricular function using radioisotopic technics in the heart cavities].

The imaging of the cardiac cavities with appropriate tracer materials (99 m Technetium or 113 m Indium), the recording of intracardiac dilution curves by radionuclide angiography and dynamic studies by gamma cinecardiography give global and regional parameters of left ventricular function which are reliable and reproducible: an index of cardiac output, intracardiac circulation times and ventricular volumes. The assessment of left ventricular contraction and global and regional ejection fractions is facilitated by coupling the gamma camera and the electrocardiogramme and computer analysis of the results. "First passage" recordings may be used to differentiate the right from the left heart chambers. "Equilibrium" studies give detailed information at rest, under stress (or leg-raising) and under pacing and/or trinitrin. Average and maximal rates of contraction derived from the ejection fraction and left ventricular contraction times are indices comparable to the rate of fibre shortening. The calculation or regional parameters point by point such as the ejection fraction, contraction time and ejection volume gives a more accurate and sensitive estimation of left ventricular function than the global left ventricular indices. They are many practical applications in cardiology especially in coronary artery disease: monitoring the changes in the acute phase of myocardial infarction, the selection of patients for aorto-coronary bypass surgery and their pre- and post-operative controls. These non-invasive, easy and reliable cardiac studies justify the development of laboratories of nuclear cardiology within departments of cardiac physiological investigation.

Animals↗