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G P Genereux

Publications and source records attributed to G P Genereux.

18 recordsLinked to original sources
PubMed1989

The Fleischner lecture: computed tomography of diffuse pulmonary disease.

The current level of computed tomography (CT) scanner resolution is such that CT is possibly the best radiographic procedure available for viewing gross pulmonary anatomy and pathology. CT densitometry, in contrast, is of limited value in assessing diffuse lung disease because of partial volume errors created by the wide range of intrathoracic tissue densities. Anteroposterior density gradients and total mean lung density can be used advantageously in a select group of patients with suspected high-density disease. The morphologic patterns of diffuse high-density lung disease as viewed on conventional roentgenograms correlate closely with those depicted on CT images. Density measurements in normal and abnormal patients suggest that the medulla of the lung may be a reservoir zone that accommodates increased blood flow via distention and recruitment of vessels under appropriate conditions. Pulmonary diseases that cause oligemia can be identified and distinguished by their combined CT densitometric and morphologic characteristics. Combined high- and low-density disease may need total integration of plain radiographs, isotopic scans, and CT scans for proper interpretation.

Humans↗
PubMed1986

Cystic fibrosis: a comparison of computed tomography and plain chest radiographs.

In patients with cystic fibrosis, plain chest radiographs may suggest the presence of bronchiectasis, bronchoceles, hilar adenopathy, or pulmonary arterial hypertension. We compared computed tomography (CT) with conventional chest radiography in 12 patients. CT clearly reveals the cause of increased linear markings, nodular lesions, and enlarged hila as seen on plain chest radiographs. It showed that nine patients had hilar adenopathy, five had enlarged pulmonary arteries, and 11 had bronchiectasis. Bronchoceles, a finding that may influence therapy, were seen on seven CT scans but on only four of the plain films.

Adolescent↗
PubMed1985

Computed tomography and the lung: review of anatomic and densitometric features with their clinical application.

The lung scan findings in 22 normal patients (9 men, 13 women; mean age 39.3 years) obtained using a GE CT/T 8800 scanner have been analyzed. Central arteries and veins can be distinguished on the unenhanced scan by following their course from the hilum on sequential scans, by identifying their relationship to bronchi, or by their vertical or horizontal orientation in the upper and lower lobes. However, arteries cannot be distinguished from veins in the lung periphery. The center of the lung (medulla) harbors "trunk" arteries, veins, bronchi and an alveolar meshwork while the periphery (cortex) is characterized by small vessels (1-3 mm) perpendicularly oriented to the pleural surface. Attenuation densities from the right lung at the aortic arch, carina and above the right hemidiaphragm were obtained followed by systematic analysis of various parameters including the mean anterior and posterior cortical and medullary attenuation density, anterior and posterior mean lung density, total mean lung density for each slice and the entire right lung, and the anteroposterior gradients. Different attenuation densities and gradients will be obtained using other models of scanners. The evidence suggests that the medulla is a "reservoir" zone, capable of accommodating increased blood flow under appropriate conditions. Clinical application of these parameters to the diagnosis of diffuse lung disease is illustrated.

Adolescent↗
PubMed1984

Normal mediastinal lymph node size and number: CT and anatomic study.

Normal lymph nodes were studied retrospectively by computed tomography (CT) in 39 patients and by dissection at autopsy in 12 cadavers. The mediastinum was divided arbitrarily into four zones relating to the left innominate vein (zone 1), pretracheal space (zone 2), precarinal/subcarinal compartment (zone 3), and aorticopulmonary window (zone 4). Of 225 lymph nodes from all zones in the CT study, 99% measured less than 16 mm in largest diameter. The average lymph node size in the four zones in the cadavers was 12.6 X 8.3 mm (length X width). Using contiguous 10-mm CT scans, lymph nodes were detected in 65%-95% of patients, depending on the zone studied. The mean number of lymph nodes on a representative section was 1.1 (range, 0-6); 72.4% of CT patients showed one to three lymph nodes per zone. There was a significant size difference (p less than 0.001) between lymph nodes residing in the superior mediastinum compared with those in the middle mediastinum contiguous to the carina. Thus, only 7% of lymph nodes in zone 1 were larger than 5 mm, whereas 90% and 67% of lymph nodes in zones 3 and 4, respectively, were larger, in the 6-10 mm range.

Adult↗
PubMed1983

The posterior pleural reflections.

The posterior mediastinal pleural reflections, which contribute to the formation of the paraspinal and paraaortic lines, were studied by conventional linear tomography, computed tomography (CT), and photodensitometry in eight normal patients; these were compared with other patients with known or suspected abnormal features. The correlated evidence indicates that these lines do not depict anatomic structures as traditionally conceived, but instead represent optical phenomena--Mach bands--formed as a result of the particular anatomic shape, rather than tissue composition, of the lung-mediastinal interface. Consequently, a line may be identified as normal, on plain radiography, in the presence of either a normal or a pathologic posterior mediastinum or pleura. The determination of normalcy cannot be made solely on the basis of the appearance of these lines; CT is the only reliable method for this differentiation.

Absorptiometry, Photon↗
PubMed1983

Conventional tomographic hilar anatomy emphasizing the pulmonary veins.

The pulmonary hili are a frequent site of interpretive uncertainty because of their complex anatomy. The right hilar shadow relates primarily to the ascending and descending pulmonary arteries and the right superior pulmonary vein, whereas the left hilar density accrues from the left pulmonary artery, left descending pulmonary artery, and left superior pulmonary vein. The right and left superior pulmonary veins are intimately associated with and inseparable from the arteries. Knowledge of the course of these veins facilitates their identification on conventional tomograms. The right and left inferior pulmonary veins lie behind the lower hili and contribute only a small increment to the normal hilar density; the horizontal course of these vessels readily distinguishes them from the vertically oriented lower lobe arteries. Prominence of both the right and left superior and inferior veins may cause hilar pseudotumors. Conventional tomograms are most helpful in understanding plain radiographs. A multiview approach in anteroposterior, 55 degrees posterior oblique, and lateral projections is recommended for a complete assessment. Computed tomography in transaxial sections adds further understanding of spatial relations in the hili, including the contributions of the pulmonary veins.

Bronchi↗
PubMed1975

The end-stage lung: pathogenesis, pathology, and radiology.

The morphological concept of an end-stage lung implies a pathologically and radiologically nonspecific appearance of diffuse lung disease which can be caused by many different disease processes. The lung can respond to injury in only a limited and stereotyped fashion; with persistent injury, these pathological changes telescope toward a common appearance, the end-stage lung, which is characterized by cystic spaces of variable size and extent throughout both lungs caused by alveolar septal dissolution, bronchiolectasia, and obstructive emphysema. The most important radiological manifestation is cystic spaces, a sign of severe, irreversible damage to that portion of the lung. Pleural thickening, cor pulmonale, spontaneous pneumothorax, calcific nodules, or scar carcinoma may also be seen.

Biopsy↗