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Biomedical subjects

M Leoncini

Publications and source records attributed to M Leoncini.

33 records · Page 2Linked to original sources
PubMed1991

Comparison of tomographic and planar imaging for the evaluation of thrombolytic therapy in acute myocardial infarction using pre- and post-treatment myocardial scintigraphy with technetium-99m sestamibi.

Pre- and post-treatment myocardial scintigraphy with technetium-99m hexakis 2-methoxy-isobutyl-isonitrile (Tc-99m sestamibi) was performed in patients who underwent thrombolytic therapy for acute myocardial infarction comparing planar imaging and single-photon emission computed tomography (SPECT). Twenty-one patients were injected with Tc-99m sestamibi before thrombolytic treatment. SPECT and planar imaging were acquired after completion of the treatment. The scintigraphy was repeated 5 days later in 20 subjects. Planar and SPECT studies were evaluated using an uptake score. Patients were divided according to the status of the infarct-related vessel (patent in 13 patients, group 1, and occluded in seven, group 2) and to the presence of functional recovery in serial echocardiographic controls (present in 10 patients, group A, and absent in 10, group B). The scintigraphic defect extent in the 5-day images correlated with the enzymatic infarct size: SPECT: r = 0.75, p less than 0.0002; planar: r = 0.68, p less than 0.002. The decrease of the uptake defects correlated with the reduction of the left ventricular wall asynergy (admission versus 1 month echocardiogram): SPECT: r = 0.92, p less than 0.000001; planar: r = 0.82, p less than 0.00001. The percent decrease of the uptake defects was significantly higher in patients in group 1 and group A compared with group 2 and, respectively, group B--SPECT: group 1: 51.4 +/- 27.7 versus group 2: 13.1 +/- 8.6, p less than 0.02; group A: 64.2 +/- 15.3 versus group B: 11.9 +/- 8.1, p less than 0.0002; planar group 1: 41 +/- 30.4 versus group 2: 7.7 +/- 6.2, p less than 0.05; group A: 52.5 +/- 24.3 versus group B: 6.1 +/- 6, p less than 0.0002. This study confirms the reliability of pre- and post-treatment myocardial scintigraphy with Tc-99m sestamibi for evaluating the outcome of thrombolytic treatment in myocardial infarction. The results seems slightly more accurate using SPECT, but a simple three-view planar study also gives useful data.

Adult↗
PubMed1991

Electromagnetic and thermal models of a water-cooled dipole radiating in a biological tissue.

An insulated, water-cooled dipole, radiating in a biological tissue, is analyzed with a theoretical electromagnetic and thermal model. The SAR and temperature distributions are calculated taking into account the effect of the water flowing inside the applicator. The steady-state temperatures in a dissipative medium, interacting with the dipole, are evaluated for several thicknesses of the external casing, water temperatures and blood perfusions. A correct design of the external casing thickness and a proper choice of the temperature and flow velocity of water allows to control the wall temperature of the applicator within physiological limits. The influence of the blood perfusion on the temperature distribution is investigated.

Electric Conductivity↗
PubMed1990

Single photon emission computed tomography with technetium-99m hexakis 2-methoxyisobutyl isonitrile in acute myocardial infarction before and after thrombolytic treatment: assessment of salvaged myocardium and prediction of late functional recovery.

Single photon emission computed tomography (SPECT) with technetium-99m hexakis 2-methoxyisobutyl isonitrile was investigated as a method to evaluate the results of intravenous thrombolytic treatment in 14 patients (11 men and 3 women) with acute myocardial infarction admitted to the coronary care unit within 4 h of the onset of symptoms. All patients received an injection of 740 MBq of the tracer before starting the thrombolytic therapy, and isonitrile tomography was performed 3 to 4 h later. The tomographic study was repeated 5 days after the acute event. The results of thrombolytic treatment were independently evaluated taking into account the clinical, electrocardiographic (ECG) and enzymatic data and the findings of left ventricular and coronary angiography. Furthermore, all patients were studied with two-dimensional echocardiography on admission, 5 days later and 1 month later. The site and extent of the perfusion defects on admission scintigraphy were consonant with the ECG and echocardiographic findings. A good correlation could be established between the 5 day scintigraphic estimate of infarct dimension and the enzymatic infarct size (r = 0.907, p less than 0.00002). The comparison between pre- and postthrombolytic treatment images enabled the identification of successful and unsuccessful reperfusion even in patients whose other noninvasive findings were inconclusive. Finally, the reduction in defect size predicted late functional improvement that was demonstrated by echocardiography performed 1 month later (r = 0.89, p less than 0.00005). The results of the study suggest the feasibility and the possible usefulness of isonitrile tomography in demonstrating the presence and size of myocardial damage and in assessing the extent of myocardial salvage after thrombolytic therapy in acute myocardial infarction.

Aged↗
PubMed1990

[Ealuation of thrombolytic treatment of acute myocardial infarct using myocardial scintigraphy with Tc-99-MIBI. Immediate results and follow-up after one year].

The aim of the study was to investigate Single Photon Emission Computed Tomography (SPECT) with technetium-99m esakis-2-methoxy isobutyl isonitrile (Tc-99m-MIBI) as a means of evaluating the results of intravenous thrombolytic treatment in patients with acute myocardial infarction. In addition, the evolution of myocardial perfusion pattern was studied. The study group included 15 patients (12 males and 3 females, mean age 57 +/- 8 years) with acute myocardial infarction admitted to the coronary care unit within 4 hours of the onset of symptoms. All patients were injected with 740 MBq of Tc-99m-MIBI before starting the thrombolytic therapy (rt-PA 100 mg i.v. in 3 hours); SPECT was performed 3 to 6 hours later. The tomographic study was repeated 5 days later. Ten patients were re-examined using Tc-99m-MIBI SPECT one year after the acute event. Taking into account the clinical, electrocardiographic and enzymatic data and the findings of two-dimensional echocardiography performed both on the fifth day and after one month, patients were divided into two groups: group A (8 patients) with probably effective reperfusion, group B (7 patients) probably unaffected by therapy. The infarct related vessel was patent in all group A patients and in 2 of the 7 patients of group B. The percent decrease in the perfusion defect size between the first and second scintigraphic studies showed a significant difference between the two groups: group A 61.2 +/- 6.8, group B 4.7 +/- 2.4% (p less than 0.002). A significant difference was also found when the results of the admission scintigraphy were compared with those of the control 1 year after: group A 80.8 +/- 8.7%, group B 20.8 +/- 13.8% (p less than 0.02). The percent decrease in the perfusion defect size between the 5-day and 1-year images was also significantly different in the two groups: group A 52.9 +/- 20.9%; group B 17.8 +/- 12% (p less than 0.02). The late perfusion improvement involved mainly the sub-epicardial layers. In conclusion, Single Photon Emission Computed Tomography with Tc-99m-MIBI clearly identified patients with effective reperfusion after thrombolytic treatment and distinguished them from subjects unaffected by therapy. Both, successfully and unsuccessfully treated patients showed a late perfusion improvement which was more evident in the successfully treated patients.

Female↗
PubMed1990

[Efficacy and duration of effect of two delayed-action preparations of gallopamil in patients with exercise angina].

In 15 subjects (13 male, 2 female) with reproducible threshold ischaemic effort angina, the efficacy and the duration of the effect of two different formulations of gallopamil in equal doses were evaluated. One of these was gallopamil slow release administered twice daily (at 7.00 a.m. and 6.00 p.m.) in doses of 100 mg. The other was action gallopamil immediate release administered four times daily (at 7.00 a.m., 1.00 p.m., 6.00 p.m., 11.00 p.m.) in doses of 50 mg. The double-blind study followed the cross-over model. After one week of run-in with placebo and two-weeks of treatment with active preparations, the patients underwent a clinical examination, an ambulatory electrocardiogram monitoring for 24 hours and two cycloergometric effort tests. The ergometric tests were carried out at 10.00 a.m. and at 5.00 p.m. on the same day so that there was a three-hour interval between the administration of both preparations (slow release and immediate release) and the morning test. The ergometric test which was carried out at 5.00 p.m. was at a ten-hour interval from the administration of slow release and at a four-hour interval from the administration of immediate release. For each period of treatment the gallopamil plasma concentrations were dosed during the ergometric test. In both these tests, the two preparations significantly increased the duration of the exercise compared to the basal values with placebo (7.9 +/- 2.3 minutes with placebo, 9.2 +/- 2.0 minutes with slow release.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1989

Psychotropic drug prescription in general practice in Italy: a two-week prevalence study.

A study on psychotropic drug monitoring was carried out in Verona over a 2-week period using information obtained during consultation with 3 GPs. Psychotropic drugs accounted for 23.4% and 24.3% of all prescriptions in men and women respectively. Benzodiazepines were the most frequently prescribed: 76% and 72% of all psychotropic prescriptions respectively in women and in men. No significant association between psychotropic drug prescription and age, sex, marital status and occupation was found in the present survey. In men only, those patients with higher educational level were more likely to receive a prescription for psychotropic drugs than those with a lower educational level. About 70% of men and 60.4% of women diagnosed by the GP as having a psychiatric problem were prescribed a psychotropic drug. However, the probability of a psychotropic being prescribed, when a psychiatric problem is identified by the GP, was significantly higher (p less than 0.05) in men than in women: odds ratio 39.37 and 16.33 respectively. Psychotropic drugs were prescribed in 35% of men and in about 48% of women in which a social problem was identified by the GP. Women were about 5 times more likely to receive a prescription than men: odds ratio 12 and 2.75 respectively. A significant influence of physical ill-health and educational level on psychotropic prescription emerged: both effects were independent of sex, psychiatric morbidity and social problems. Using a logistic regression analysis, an interactive effect between sex and conspicuous psychiatric morbidity and between sex and social problems was also found.

Adult↗
PubMed1989

[Myocardial scintigraphy using 99m-technetium pyrophosphate in the diagnosis of acute myocardial infarct. Comparison of planar and tomographic imaging].

The aim of the study was to compare the effectiveness of planar and single photon emission computed tomography (SPECT) imaging with 99mTc-pyrophosphate in the verification of acute myocardial infarction. The study was performed on 39 patients (26 males, 13 females) aged between 41-76 years (mean 61 +/- 9) admitted to CCU for acute myocardial infarction. Patients underwent planar and SPECT imaging using a double-head-camera with a 360 degrees rotation arc within 6 days of admission. Planar images were obtained in three standard projections (anterior, LAO 45 degrees, LAO 75 degrees) with acquisitions of 500000 counts each. To obtain SPECT images ninety projections, each lasting 20 seconds, were taken; subsequently images reconstruction was performed using an iterative algorithm. Positive planar images were found in 21 out of 39 patients; SPECT images were positive in 33 patients. In "Q wave" myocardial infarctions planar images were positive in 13 out of 15 patients, whereas SPECT images were positive in all subjects; in "non-Q wave" myocardial infarctions planar images were positive in 6 out of 22 patients whereas SPECT images were positive in 16 patients (p less than 0.005); in 2 patients with left bundle branch block both planar and SPECT images were positive. A bidimensional echocardiogram was carried out on 38 patients: an alteration of left ventricular regional wall motion was present in 30 subjects; in one patient diffuse hypokinesia was present.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Nitrate-enhanced gated technetium 99m sestamibi SPECT for evaluating regional wall motion at baseline and during low-dose dobutamine infusion in patients with chronic coronary artery disease and left ventricular dysfunction: comparison with two-dimensional echocardiography.

BACKGROUND: The value of gated single photon emission computed tomography (SPECT) in the assessment of wall motion (WM) in patients with severe perfusion defects and in the evaluation of low-dose dobutamine (LDD)-induced changes is not yet established. In patients with chronic coronary artery disease who have left ventricular (LV) dysfunction, the results of nitrate-enhanced technetium 99m sestamibi (sestamibi) gated SPECT for the evaluation of resting and LDD WM were compared with those of baseline and LDD echocardiography (LDDE). METHODS AND RESULTS: Thirty-seven patients underwent echocardiography and nitrate-enhanced sestamibi gated SPECT within 1 week at rest and during LDD infusion. WM was scored from 1 (normal) to 4 (dyskinetic) by using a 16-segment model. Segments with sestamibi uptake less than 30% were considered unsuitable for WM analysis (36 of 592 segments). Echocardiography was technically unreliable in 10 of 592 segments. The precise agreement between echocardiography and gated SPECT for baseline regional WM was 68.4% (kappa = 0.54), without significant differences for the involved coronary artery territory. The agreement for +/- 1 WM scoring was 96.5% (kappa = 0.94). Contractile reserve during LDD was detected by means of echocardiography in 36% and by means of sestamibi gated SPECT in 33% of baseline asynergic segments. Agreement for detection of WM improvement in response to LDD was 74% (kappa = 0.41). The overall and +/-1 WM score agreement for LDD WM was 67.5% (kappa = 0.50) and 94.7% (kappa = 0.91), respectively. A significant correlation between echocardiography and gated SPECT was observed for both baseline (p = 0.78) and LDD (p = 0.74) WM score index. CONCLUSIONS: In patients with coronary artery disease who have LV dysfunction, nitrate-enhanced sestamibi gated SPECT allows a reliable WM evaluation, both at rest and during LDD infusion, in almost all segments and provides results in agreement with LDDE.

Adult↗
PubMedDate not supplied

Usefulness of distinct activity thresholds according to baseline regional asynergy for predicting functional recovery in patients with chronic coronary artery disease and left ventricular dysfunction: a study with nitrate-enhanced sestamibi gated SPECT.

BACKGROUND: The role of gated single photon emission computed tomography (SPECT) in improving viability detection with the use of perfusion imaging is uncertain. This study aimed to verify whether the classification of baseline regional dysfunction with gated SPECT helps to predict functional recovery with the use of quantitative perfusion imaging. METHODS AND RESULTS: Resting nitrate-enhanced sestamibi gated SPECT was performed in 31 patients with left ventricular dysfunction, who later underwent coronary revascularization. With the use of a 16-segment model, tracer activity was quantified, and wall motion and thickening were estimated with a 4-point scoring scheme. Reversible dysfunction was assessed with follow-up gated SPECT. According to receiver operating characteristic curve analysis, the best overall cutoff for predicting reversible dysfunction in asynergic segments was 50% of peak activity or greater, with 83% sensitivity, 54% specificity, and 64% accuracy. When the segments were divided according to wall motion in resting gated SPECT, the optimal activity cutoff was greater than 68% for hypokinetic and 50% or greater for adyskinetic segments. With the use of 2 thresholds, the overall sensitivity remained good (76%), whereas specificity increased to 73% (P <.0005) and accuracy to 74% (P <.02). CONCLUSIONS: Regional dysfunction assessment directly on perfusion images permits use of different activity thresholds with an improvement over a single cutoff for all asynergic segments. Therefore combining perfusion and functional data with nitrate-enhanced gated SPECT at rest appears to be a promising approach for viability detection.

Adult↗
PubMedDate not supplied

A dipole-type intracavitary hyperthermic applicator with a metallic reflector: experiments and theoretical analysis.

A water-cooled electromagnetic (EM) dipole, for intracavitary hyperthermia, embodying a metallic reflector to give directional characteristics to the SAR and then to the heating pattern in the biological tissue, is considered. The influence of the reflector on the SAR deposition has been theoretically modelled with an EM analysis which uses the method of moments (MOM). A thermal model, based on the heat transfer equation, is used to predict temperature distribution, which exhibits a directivity related to the angular extension of the reflector. Experiments have been carried out in a polyacrylamide phantom. The temperature distribution detected with a liquid crystal sheet shows fairly good agreement with theoretical predictions.

Electromagnetic Phenomena↗
PubMedDate not supplied

Repeated 99mTc-Sestamibi studies for the evaluation of salvaged myocardium and of its relationship with postinfarction ischemia.

Pre- and post-treatment myocardial scans with 99mTc-Sestamibi demonstrated effective reperfusion after thrombolysis in a patient with acute myocardial infarction. Late follow-up images showed at rest a further noteworthy reduction of the uptake defect and that during exercise a large part of the salvaged territory became ischemic. This report demonstrates that a remarkable amount of myocardium in the posttreatment images was hibernated; furthermore, it was possible to visualize directly that the salvaged territory is the actual site of exercise induced postinfarction ischemia.

Heart↗