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Biomedical subjects

B Alfano

Publications and source records attributed to B Alfano.

30 records · Page 2Linked to original sources
PubMed1990

Effects of intravenous verapamil on left ventricular relaxation and filling in stable angina pectoris.

Left ventricular (LV) diastolic function is often impaired in coronary artery disease (CAD). To assess whether verapamil could improve LV diastolic properties, 12 patients with CAD undergoing right- and left-sided cardiac catheterization, as well as simultaneous radionuclide angiography, were studied before and during intravenous administration of verapamil (0.1 mg/kg as a bolus followed by 0.007 mg/kg/min). The heart rate was kept constant by atrial pacing in both studies. LV pressure-volume relations were obtained. Verapamil decreased LV systolic pressure (130 +/- 22 to 117 +/- 16 mm Hg, p less than 0.01) and the end-systolic pressure/volume ratio (2.4 +/- 1.3 to 1.6 +/- 0.5 mm Hg/ml, p less than 0.05), and increased LV end-diastolic (13 +/- 4 to 16 +/- 4 mm Hg, p less than 0.02) and pulmonary capillary pressures (10 +/- 5 to 12 +/- 5 mm Hg, p less than 0.005). Despite such negative inotropic effects, cardiac index increased (3.4 +/- 0.7 to 3.9 +/- 0.6 liters/min/m2, p less than 0.02). The time constant of isovolumic relaxation shortened (63 +/- 14 to 47 +/- 9 ms, p less than 0.02); peak filling rate increased (370 +/- 155 to 519 +/- 184 ml/s, p less than 0.001; 2.6 +/- 1.1 to 3.3 +/- 0.9 end-diastolic counts/s, p less than 0.02; and 4.1 +/- 1.6 to 5.5 +/- 1.5 stroke counts/s, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Quantitation of left ventricular asynchrony on radionuclide angiography phase images.

Quantitation of left ventricular (LV) asynchrony is relevant in clinical cardiology, as well as in evaluating LV mechanical properties. Radionuclide angiography (RA) phase images are extensively used, and asynchrony is usually assessed by computing the standard deviation of phase angle distribution (SD). However, SD is dependent on count statistics and does not take into account the spatial distribution of asynchrony. In this study a new index to evaluate asynchrony on phase images is presented (differential uniformity parameter, DUP). DUP is based on the frequency analysis of phase images. Diagnostic accuracy and reproducibility of either SD or DUP were tested. Reproducibility was evaluated in 15 patients studied by RA twice within a few minutes. DUP showed a better reproducibility than SD. Diagnostic accuracy was estimated in 84 patients, divided into four subgroups on the basis of coronary arteriography and contrast ventriculography findings: (a) 25 control subjects, (b) 16 patients with coronary artery disease (CAD) and normal LV wall motion, (c) 23 patients with CAD and LV hypokinesia and (d) 20 patients with CAD and LV dyskinesia. Relative diagnostic ability was assessed by comparing the areas under receiver-operating characteristic curves. DUP's area was larger than SD's when group D was tested against all the other groups (DUP's area = 87% +/- 5%, SD's area = 76% +/- 7%; P less than 0.01). Thus, our study indicates that DUP is more reproducible and more accurate than SD in identifying patients with CAD and LV dyskinesia.

Coronary Disease↗
PubMed1988

Quantitative assessment of blood-brain barrier permeability in multiple sclerosis using 68-Ga-EDTA and positron emission tomography.

Fifteen patients with definite multiple sclerosis were examined with high volume delayed (HVD) CT scan and positron emission tomography (PET) using 68-Ga-EDTA as a tracer. The passage of 68-Ga-EDTA across the blood-brain barrier (BBB) was measured by using multiple graphical analysis. This method permits the simultaneous calculation of a blood to brain influx constant Ki (ml/g-1 min-1) and of the plasma volume Vp (ml/g-1). Focal areas of abnormal CT enhancement and pathological accumulation of 68-Ga-EDTA were visualised in four patients who were all examined during a clinical exacerbation of the disease. The mean Ki value measured in these areas was 12.5, SD 3.4 indicating a moderate but significant increase of BBB permeability compared with the value found in normal tissue (3.2, SD 0.9). No parallel increase in Vp values was found in these pathological areas. Quantitative data obtained with PET seems to provide further insight into the study of BBB function in multiple sclerosis.

Adolescent↗
PubMed1988

[The use of single-photon emission computed tomography in cardiology].

The tomographic distribution of thallium 201 in the myocardium was studied with a gamma camera with 2 detectors (29 cms in diameter) with 37 photo multipliers each. The camera was connected to a PDP computer with a 256 Kbytes memory. Thallium 201 in a dose of about 74 MBq 2 mCi was used in normal subjects, patients with coronary artery disease and with cardiac hypertrophy. Tomographic sections were obtained every 1.2 cms in the sagittal and frontal projections. The distribution of the Thallium was uniform in normal and hypertrophic hearts. Focal defects were seen in C.A.D. Single-photon emission computerized tomography was instrumental in determining the extension of the damage of the myocardium to areas which appeared normal in the regular thallium 201 scintigrams.

Cardiomyopathies↗
PubMed1987

Effects of intravenous verapamil administration on left ventricular diastolic function in systemic hypertension.

The effects of intravenous verapamil administration (0.1 mg/kg as a bolus followed by an infusion of 0.007 mg/kg/min) were studied using high-temporal-resolution radionuclide angiography in 27 patients with hypertension. Verapamil administration increased heart rate from 69 +/- 11 to 75 +/- 12 beats/min (p less than 0.001) and decreased systolic, diastolic and mean blood pressures (BPs) from 155 +/- 21/102 +/- 12 mm Hg (mean 119 +/- 14) to 142 +/- 19/95 +/- 12 mm Hg (mean 109 +/- 13) (p less than 0.001 for all). Ejection fraction decreased significantly (from 65 +/- 10% to 60 +/- 11%, p less than 0.005); peak filling rate, however, increased significantly only in patients in whom it was subnormal in the basal study (from 2.2 +/- 0.4 to 3.0 +/- 0.6 end-diastolic counts/s, p less than 0.001). These latter patients had significantly higher values of left ventricular (LV) mass index than patients with normal or increased peak filling rate (129 +/- 22 vs 112 +/- 22 g/m2, respectively, p less than 0.05). The isovolumic relaxation period changes were inversely related to the baseline values (r = 0.83, p less than 0.001). In the subgroup of patients in whom isovolumic relaxation period lengthened, time to end systole decreased (from 360 +/- 31 to 329 +/- 30 ms, p less than 0.025) and time to onset of rapid filling increased (from 420 +/- 31 to 451 +/- 34 ms, p less than 0.025), whereas these 2 intervals had opposite patterns in patients in whom isovolumic relaxation period decreased or did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1980

[Post-operative radiotherapy of supraglottic carcinoma: technique with three fields of 60Co (author's transl)].

Post-operative radiotherapy of supraglottic carcinoma, because of the high risk of lymph-nodal metastases, should include irradiation of the primary tumour as well as regional lymph-nodes (jugular chain, posterior cervical. supraclavicular, submental and submaxillary triangle nodes). Taking into account the anatomically complex region to be irradiated and the critical organs present within the areas involved, the authors present a treatment plan that provides the neck irradiation through three 60Co fields: Two posterior oblique and a posterior one with median lead block in correspondence to the spinal cord. The isodose curves (at jaw level, at the medium plane of the neck and at clavear level) show that the required dose distribution has been achieved by safeguarding of radiation tissue tolerance of medulla. The authors conclude that only the adoption of a "different" procedure, i.e. outwith of any reciprocal relation "portal-target", has permitted the overcoming of anatomo-clinical problems linked with the region to be irradiated. The authors believe that the adopted methodology, the only acceptable in case of irradiation of anatomically complex and articulate regions, can be also extended to simple cases where immediate and intuitive solution is not always the most appropriate, one.

Cobalt Radioisotopes↗
PubMedDate not supplied

Multiparametric display of spin-echo data from MR studies of brain.

A magnetic resonance (MR) image processing technique that uses a single color image for simultaneous presentation of spin-echo information and its application to MR studies of the brain is described. Relaxation rate and proton-density maps were calculated from 160 brain MR studies performed at 1.5 and 1.0 T with standard spin-echo sequences. Maps were fused into single color images, with R1, R2, and proton density coded, respectively, by red, green, and blue. The possibility of standardizing the technique was evaluated. Comparative analysis of color and conventional MR images of white matter disease and brain tumors was performed to assess intra- and interobserver variability. Unequivocal and reproducible chromatic characterization of normal brain structures and a variety of lesions was obtained. Intra- and interobserver analysis showed that color images can be used as a diagnostic tool. The technique may provide a simplified and timesaving approach for interpretation and presentation of brain MR studies.

Adult↗
PubMedDate not supplied

Premature aging in Werner's syndrome spares the central nervous system.

Werner's Syndrome is a rare genetic disease, characterized by premature aging of many tissues and organs. We studied the brain morphology and function in two patients with Werner's syndrome to assess the possible involvement of the central nervous system in this premature aging process. The two patients (brother and sister, respectively) were studied by magnetic resonance imaging (MRI) and angiography (MRA), single photon emission computed tomography (SPECT) with (99mTc)-d,l-hexamethyl propilene amine oxime (HMPAO), positron emission tomography (PET) with 2(18F)-Fluoro-2-deoxyglucose (FDG), electroencephalography (EEG), and electromyography (EMG). Some of these investigations were also repeated after 1 year. The results of all these studies were normal. The premature aging process in patients with Werner's syndrome, while affecting most tissues, seems to spare the central nervous system.

Adult↗
PubMedDate not supplied

Simplified, noninvasive PET measurement of blood-brain barrier permeability.

Blood-brain barrier (BBB) permeability to [68Ga]EDTA was measured by positron emission tomography (PET) in four normal volunteers and in 11 patients with brain tumors. A unidirectional transfer constant, Ki, was calculated applying multiple-time graphical analysis (MTGA). This method allows the detection of backflux from brain to blood and, by generalization, the measurement of the constant Kb (brain to blood). Furthermore, the need for an independent measurement of the intravascular tracer is obviated: MTGA itself provides an estimate of the cerebral plasma volume (Vp). In the four normal volunteers the Ki was 3.0 +/- 0.8 X 10(-4) ml g-1 min-1 (mean +/- SD) and the Vp 0.034 +/- 0.007 ml g-1. A net increase in Ki up to a maximum of 121.0 X 10(-4) ml g-1 min-1 (correspondent value of Kb = 0.025 min-1) as well as an increase of Vp was observed in malignant tumors. The input function was calculated using both the [68Ga]EDTA concentration in sequential arterial blood samples and, noninvasively, the activity derived from the superior sagittal sinus image. The values of Ki and Vp from these two calculations were in good agreement. The application of MTGA to PET permits the evaluation of passage of substances across the BBB without making assumptions about the compartments in which the tracer distributes.

Adult↗
PubMedDate not supplied

Simultaneous display of multiple MR parameters with "quantitative magnetic color imaging".

A new technique for simultaneous display of multiple MR parameters with a single color-coded image is described. The method is based on the multiparametric nature of MR signals and benefits from the physiologic ability to discriminate color levels better than gray levels. The T1 and T2 relaxation rate maps are first obtained from multi-echo SE and partial saturation sequences. Each parameter is subsequently represented with one or with a combination of two fundamental colors (red, green, blue) into a composite quantitative magnetic color image. Each mixture of chromatic components in the magnetic color image represents a unique combination of the two relaxation parameters, easily interpretable by the human eye, without loss of anatomic information. The potential advantages of the technique are discussed and some practical applications are presented.

Brain↗
PubMedDate not supplied

[Positron-emission tomography with fluorine-18-deoxyglucose in the staging and control of patients with lymphoma. Comparison with clinico-radiologic assessment].

INTRODUCTION: The clinical applications of fluorine-18-deoxyglucose Positron Emission Tomography (FDG PET) have been proposed on account of experimental evidence of increased glucose metabolism in tumor cells. MATERIAL AND METHODS: We examined 98 lymphoma patients--33 with Hodgkin and 65 with non-Hodgkin disease--with FDG PET and compared its findings with those of clinical and conventional radiologic studies. FDG PET was also used to follow-up 32 patients and the results were once again compared with clinical and radiologic data. RESULTS: During staging, 138 lesions were found, 82 of them (59%) in nodal and 56 (41%) in extranodal locations. Extranodal tumor sites were found in 39 patients (40%), namely 4 with Hodgkin (12%) and 35 with non-Hodgkin (54%) disease. FDG PET findings were in agreement with clinical and radiologic results in all nodal and extranodal lesions, since all of them exhibited abnormally increased FDG uptake. PET detected new tumor sites in 6 patients. In the follow-up, agreement was observed in the majority (78%) of lesions, 30 of them in complete regression, 15 in partial regression and 17 in progression; however, the diagnostic results were in disagreement in the remaining (22%) tumor sites: no abnormal FDG uptake was found in 9 cases despite the persistence of radiologic abnormalities (post-treatment fibrosclerosis). Slightly increased FDG uptake (residual disease) was found in the other 8 lesions, where there was no clinical and/or radiologic evidence of disease. CONCLUSIONS: FDG PET is a functional imaging technique useful to diagnose lymphomas and providing metabolic characterization of cancer abnormalities. Whole body PET permits the simultaneous assessment of nodal and extranodal lymphoma localizations. During the follow-up, FDG PET permits better monitoring of treatment effects than clinical and radiologic examinations.

Female↗