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Biomedical subjects

F Fazio

Publications and source records attributed to F Fazio.

At least 253 records · Page 14Linked to original sources
PubMed1982

Squamous cell carcinoma with sarcomatoid stroma.

Two cases of squamous cell carcinoma with sarcomatoid stroma are presented. One tumor was located in the soft palate that metastasized to a neck lymph node; the epithelial and the spindle cell component of the tumor at the primary as well as at the metastatic site showed ultrastructural features of squamous cell carcinoma. The other case, a laryngeal tumor with spindle cell stroma, was shown by ultrastructural studies to be composed of proliferating fibroblasts. The diagnostic problems and the controversies regarding classification and behavior of these rare tumors of upper respiratory tract and upper gastrointestinal tract are discussed.

Carcinoma↗
PubMed1982

Clinical ventilation imaging with In-113m aerosol: a comparison with Kr-81m.

Following routine ventilation (Kr-81m)/perfusion (Tc-99m) scanning, we obtained aerosol ventilation scans using a solution of In-113m albumin and a settling-bag system. The large-volume settling bag reduces deposition of particles in the large airway by removing large droplets. The patient inhales the aerosol with 5-10 min of tidal breathing, then lung scans are obtained on a gamma camera. The energy of In-113m allows the ventilation scanning to be performed after Tc-99m perfusion scanning. Semiquantitative scoring of regional ventilation showed a close correlation (r = 0.97) between Kr-81m and In-113m aerosol ventilation scans. The aerosol technique gave a slight underestimation of ventilation compared with Kr-81m. This is explained by a slightly reduced penetration of particles to the periphery of the lung in patients with severe obstructive airways disease. In all cases, however, the aerosol did visualize all ventilated regions. The results indicate that this readily available aerosol technique can be useful for clinical ventilation imaging in multiple views.

Adult↗
PubMed1981

Quantitative measurement of regional extravascular lung density using positron emission and transmission tomography.

A technique has been developed to measure regional values of vascular and extravascular lung density using positron emission and transmission tomography. Quantitative values of lung density in a transaxial plane are obtained by recording transmission scans during the exposure of a ring source of positron emitting germanium/gallium-68, which encircles the subject in the plane of the scan. Values of blood density are obtained by scanning in the emission mode following the labeling of the subject's red blood cells with a quantity of C-carbon monoxide inhaled as a bolus. Subtraction of the normalised blood volume scan from the normalised lung density (transmission) scan provides regional values of extravascular lung density. The response of the transmission scan to changes in density was obtained by scanning different tissue equivalent materials in the density range 0.02 to 1.0 g cm-3. This resulted in a linear relationship between pixel counts and density. Density measurements made in vitro on simulated chest phantoms suggest that, at worst, random errors of 3.5% and systematic errors (due to the influence of the chest wall) of between 10 and 15% will be incurred when measurements are made in vivo on lungs of average normal density (0.3 g cm-3). The random error associated with the emission scan (arising from counting statistics alone) was found to be 1.2%. Measurements of lung density made on five normal subjects (supine) resulted in a mean density of 0.29 g cm-3 for a region in the lower (caudal) part of the lung, with a range of values between 0.26 and 0.32 g cm-3 from subject to subject. A pronounced anteroposterior gradient of both lung density and blood density was observed, while the gradient of extravascular lung density was quite small. The mean value of the ratio extravascular: vascular lung density for both caudal and cranial lung regions was 0.92 +/- 0.25.

Adult↗
PubMed1981

Clinical ventilation-perfusion scintigraphy.

Ventilation-perfusion scintigraphy is an established procedure for the investigation of lung disease. Perfusion scans are commonly obtained with a gamma-camera following injection of 99mTc-labelled microspheres. For the assessment of regional lung ventilation, a number of techniques are now being employed, i.e. 133Xe and 127Xe single breath/washout studies, continuous inhalation of 81mKr and inhalation of radioactive aerosols. The latter two methods are now gaining consideration in clinical practice. Lung perfusion scanning is highly sensitive for detection of regional abnormalities of blood flow; the diagnosis of pulmonary embolism remains the most important clinical application of the technique. In this context, the use of a ventilation scan is required in order to increase the specificity of the procedure. In general, lung ventilation-perfusion scintigraphy is of great value for the management of patients with both primary lung disease and heart disease, by providing pathophysiological information of importance for the diagnosis, follow up and the functional evaluation of the patient.

Asthma↗
PubMed1981

Clinical applications of radionuclide lung scanning in infants and children.

Krypton 81m ventilation and technetium 99m perfusion lung scans in anterior, posterior and oblique views in 86 children (age range 14 days to 15 years) with various paediatric problems were obtained. On reviewing these studies we found four main areas of clinical usefulness. (a) Establishing the diagnosis; in a relatively small number of patients the lung scan was essential for either establishing the exact diagnosis or directing attention to the abnormal area. (b) Refuting a diagnosis: the two main groups in this category include possible bronchiectasis and inhaled foreign body. (c) Establishing the extent of the disease; radionuclide studies enable one to assess and follow up the extent of the disease in children with lower respiratory problems; a lung scan may obviate the need for bronchography in bronchiectatics failing to respond to medical treatment and for whom surgery is being considered. Repeat studies are useful in following the natural history or the response to treatment of various lung conditions. (d) Assessing the success of surgical procedures on the heart and on abnormal pulmonary arteries. We indicate that 81Krm ventilation/99Tcm perfusion scanning are particularly useful in small children in whom tests of overall pulmonary function cannot be carried out because of lact of co-operation.

Adolescent↗
PubMed1981

Effect of inhaled salbutamol on mucociliary clearance in patients with chronic bronchitis.

We investigated, in a double blind fashion, the acute effect of an inhaled beta 2-agonist drug (salbutamol) on mucociliary clearance in 20 patients with chronic bronchitis: ten treated with the drug and the remaining ten with placebo. Following inhalation of pre-sized human albumin microspheres with a mass median diameter of 1.5 micrometers, radioactivity was recorded for one hour (control period) with the patient in the supine posture with a large field computerized gamma camera collimated over the chest. At the end of the first hour, without moving the patient, either salbutamol (500 micrograms) or placebo was nebulized from a commercial canister and recording carried out for another two hours. At the end of the recording period areas of interest were selected and time activity curves generated, from which the percentage activity cleared in the first, second and third hour was calculated. Whereas no significant differences in clearance between the two groups were found in the control period, inhaled salbutamol significantly increased mucociliary clearance rate; particle removal in the second hour (test period) was 36.42 +/- 5.61 (SD) percent for the group treated with salbutamol, and 10.87 +/- 2.47 (SD) percent for the group receiving placebo.

Aerosols↗
PubMed1980

Tomographic assessment of cerebral perfusion using a single-photon emitter (krypton-81m) and a rotating gamma camera.

Continuous carotid infusion of short-lived krypton-81m (t1/2 13 sec) yields an assessment of regional cerebral perfusion. This assessment can be obtained in three dimensions if activity is recorded with a rotating gamma camera and a computer to reconstruct krypton-81m distribution in tomographic sections. These showed several advantages over conventional views: (a) visualization of blood-flow distribution within brain structures (gray and white matter, basal ganglia); (b) more accurate location and evaluation of areas of relatively reduced or increased perfusion; (c) better definition of patterns of collateral circulation; (d) greater sensitivity and specificity in detecting and defining blood-flow changes during physiological activation studies. A limitation of the krypton-81m technique is its invasiveness. However, this study shows that the combination of new advances in radiochemistry with single-photon emission computed tomography may result in accessible methods for assessing, noninvasively and in three dimensions, the behavior of cerebral function in man.

Brain Diseases↗
PubMed1979

Improvement in regional ventilation and perfusion after radiotherapy for unresectable carcinoma of the bronchus.

Ventilation/perfusion scans were obtained in 45 patients with unresectable carcinoma of the bronchus. Of these 45 patients, 35 were reinvestigated shortly after radiotherapy and 17 of them had additional later follow-up studies. Both ventilation and perfusion were always abnormal in the lung affected by the tumor; perfusion was usually more impaired than ventilation. These abnormalities were difficult to detect or to evaluate from the standard chest radiograph. After radiotherapy, ventilation improved in 83% and perfusion in 86% of the patients. This improvement was associated with amelioration of breathlessness, which improved in 74% of the patients. Slow but progressive deterioration of regional ventilation and perfusion were subsequently observed. This was often associated with the development of radiation fibrosis. Spirometric measurements (VC, FEV1) were moderately imparied at the initial assessment (83% and 66% of predicted, respectively), probably due to coexisting chronic airway obstruction, and did not show significant changes after radiotherapy or during the follow-up. Radionuclide studies of regional perfusion and ventilation proved more sensitive and more specific than tests of overall lung function for the functional assessment and follow-up of patients with unresectable carcinoma of the bronchus.

Adenocarcinoma↗
PubMed1978

81mKr ventilation and 99mTc perfusion scans in chest disease: comparison with standard radiographs.

In 75 patients with various pulmonary disorders, ventilation and perfusion scans were obtained in multiple views with the 81mKr/99mTc technique and compared with an evaluation of regional ventilation and perfusion derived from the standard chest radiograph. In emphysema, the chest film correlated poorly with ventilation-perfusion scans, showing a trend to underestimate the functional impairment. In chronic bronchitis and asthma, large segmental defects observed on both ventilation and perfusion scans were associated with a normal chest radiograph. Typical findings in pulmonary embolism were segmental defects on perfusion scan with normal ventilation scan and clear lung fields on the chest film. In chronic left heart disease, plain films were inaccurate in predicting alteration of the base-to-apex perfusion gradient observed on the scan.

Airway Obstruction↗
PubMed1977

Assessment of regional cerebral blood flow by continuous carotid infusion of krypton-81m.

In order to obtain functional images of brain perfusion, we exploited a new concept, which is to take advantage of the short half-life of a radioactive tracer. Under continuous intracarotid infusion of a solution of Kr-81m (T1/2 = 13 sec; produced from its parent, 4.6-hr Rb-81), this tracer will never reach equilibrium within the brain because of the rapid radioactive decay. Its distribution will therefore reflect regional arrival of the nuclide, indicating regional cerebral blood flow rather than volume. During continuous infusion of Kr-81m, perfusion images can be obtained by simply collecting counts with a gamma camera and recording on Polaroid film. The procedure is readily repeatable in order to get images in multiple veiws or to follow minute-by-minute changes of cerebral perfusion.

Aged↗
PubMed1976

Measurement of regional pulmonary oedema in man using radioactive water (H215O).

Regional extravascular lung water (rELW) has been measured in normal subjects and in patients with left heart diseases using a double-indicator dilution technique and external counting over the chest. Gamma-emitting radioisotopes were injected intravenously, 113Inm as a vascular non-duffusible indicator, and H215O as a freely diffusible indicator. Time activity curves were then recorded over the upper and lower zones of the lung in the supine position with external probes. rELW per unit of blood volume and rELW per unit of blood flow were increased in patients with raised left atrial pressure even in the presence of radiologically clear lung fields. There was a uniform distribution of these ratios between upper and lower zones in normals, whereas in patients rELW was preferentially distributed in the lower zones.

Blood Flow Velocity↗
PubMed1975

Assessment of regional ventilation by continuous inhalation of radioactive krypton-81m.

A simple technique is described for producing high-quality functional images of regional ventilation during physiological tidal breathing of the inert gas 81mKr. These images are quickly obtained on a gamma-camera without the need of computerized systems for data acquisition and display and are directly comparable with those of perfusion obtained with 99mTc-labelled macroaggregates. The short time required for the procedure, its simplicity, and the extremely low absorbed-radiation dose enable serial images of ventilation to be obtained in multiple views.

Dyspnea↗