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Biomedical subjects

T C McLoud

Publications and source records attributed to T C McLoud.

At least 19 recordsLinked to original sources
PubMed1992

T-cell alveolitis in lung lavage of asbestos-exposed subjects.

In sarcoidosis and idiopathic pulmonary fibrosis, it has been reported that lymphocyte proportions in lung lavage predict the subsequent clinical course. Recent evidence has suggested that lymphocytes are important in the alveolitis of asbestosis. We hypothesized that a greater relative proportion of T-lymphocytes in lung lavage of asbestos-exposed subjects is associated with immune activation and may predict the subsequent clinical course. We assessed lymphocyte subsets in lung lavage and peripheral blood (PB) of 97 asbestos-exposed subjects and 10 unexposed normal, using flow cytometry analysis of monoclonal antibody-treated cells. T-cell alveolitis was defined as follows: [%lymphocytes in lavage x %CD3 in lavage] greater than 2 SD above that product in normals. Eighteen subjects had T-cell alveolitis (group 1) and 79 did not (group 2). There were no significant differences between the groups in age, smoking status, duration of exposure, lung function results, or frequency of plaques or profusion greater than or equal to 1/0. Percent CD2 was higher in lavage of group 1 compared with group 2. There was a trend for higher %Ia in lavage of group 1 compared with group 2. These results identify a subgroup of asbestos-exposed subjects with T-cell alveolitis but no present excess of asbestos-related disease who may be at risk for future asbestos-related disease.

Adult↗
PubMed1992

Bronchogenic carcinoma: analysis of staging in the mediastinum with CT by correlative lymph node mapping and sampling.

One hundred forty-three patients with bronchogenic carcinoma were studied prospectively with computed tomography (CT) to determine the accuracy of CT in the evaluation of mediastinal nodal metastases. Mediastinal lymph nodes were localized according to the lymph node mapping scheme of the American Thoracic Society and were considered abnormal if they exceeded 1 cm in short-axis diameter. All patients underwent surgical staging, which consisted of either mediastinoscopy alone or mediastinoscopy and thoracotomy. At the time of surgical staging, all accessible nodes were either removed or sampled. The sensitivity of CT for mediastinal nodes on a per-patient basis was 64%, with a specificity of 62%. The sensitivity of CT for individual nodal stations involved with tumor was only 44%. The presence of obstructive pneumonitis did not appreciably alter the sensitivity of CT, but the specificity was lower (43%). The likelihood of metastases increased with lymph node size; however, seven of 19 (37%) lymph nodes that measured 2-4 cm in short-axis diameter were hyperplastic and did not contain metastases. The relative insensitivity of CT makes formal nodal sampling at the time of mediastinoscopy or thoracotomy essential to detect lymph node metastases.

Adult↗
PubMed1992

Conventional radiography in the diagnosis of asbestos-related disease.

Standard chest radiography, despite its limitations, remains an important means of evaluating the asbestos-exposed worker. Because of its wide availability, low radiation dose, and low cost, it will continue to be the standard imaging procedure for the screening of asbestos-exposed populations.

Asbestos↗
PubMed1992

Thoracic disease in the immunocompromised patient.

Thoracic disease in the HIV negative immunocompromised host is most frequently caused by infection. Patterns of involvement produced on the chest radiograph include (1) lobar or segmental consolidation, (2) nodules with rapid growth and/or cavitation, and (3) diffuse lung disease. The lung also may be directly involved by lymphoma, metastases, drug reactions, radiation pneumonitis, or nonspecific interstitial pneumonitis. The lung is a frequent target organ for opportunistic infections in AIDS patients, particularly of Pneumocystis carinii pneumonia and tuberculosis. Computed tomography may be particularly helpful in these patients in the detection of early disease and in the characterization of patterns and extent of involvement as well as complications.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Differentiation of bronchogenic carcinoma from postobstructive pneumonitis by magnetic resonance imaging: histopathologic correlation.

Obstructive pneumonitis frequently occurs distal to hilar bronchogenic carcinomas or in lung adjacent to peripheral tumors. The article evaluates the role of MRI in the differentiation of tumor from pneumonitis. Twelve patients underwent MRI of the thorax before surgery. T1-weighted (SE 310/20) and T2-weighted (SE 2000/60-120) images were obtained through the tumor and presumed areas of pneumonitis. Five histologic types of pneumonitis were identified on pathologic examination of the 12 specimens. Cholesterol pneumonitis, found in 7 patients, was the most common type. Organizing pneumonitis, bronchiectasis with mucus plugs, atelectasis, and abscess were found in 3, 4, 2, and 1 patients, respectively. MRI was able to differentiate tumor from pneumonitis in 5 of 6 patients with a hilar mass and in 5 of 6 patients with a peripheral tumor. This was achieved by a visual difference in signal intensity on heavily T2-weighted (SE 2000/120) images. Cholesterol pneumonitis and bronchiectasis with mucus plugs were always hyperintense relative to tumor, and organizing pneumonitis and atelectasis were isointense and indistinguishable from tumor. MRI can differentiate tumor from pneumonitis provided that pneumonitis is of the cholesterol type or if there are mucus plugs in the collapsed lung.

Aged↗
PubMed1991

Effect of patient positioning after needle aspiration lung biopsy.

Fifty-five patients who underwent fluoroscopically guided needle aspiration lung biopsy were randomly assigned to one of two postbiopsy treatment groups: Patients were placed recumbent with puncture site either down (n = 36) or up (n = 19) for at least 1 hour. No significant difference in pneumothorax rate was seen between the two groups. Chest tube placement, however, was required in 21% (four of 19) of the puncture-site-up group versus 3% (one of 36) of the puncture-site-down group, which was a significant difference (P = .04). Puncture-site-down postbiopsy positioning reduces the proportion of patients requiring chest tube placement after lung biopsy.

Biopsy, Needle↗
PubMed1991

Asbestos exposure and asbestos-related pleural and parenchymal disease. Associations with immune imbalance.

The study hypothesis was that asbestos exposure and asbestos-related pleural plaques and interstitial disease are associated with (1) immune imbalances favoring helper-inducer T-cell subsets in blood and bronchoalveolar lavage (BAL) and (2) T-lymphocyte accumulation in BAL. One hundred twenty-two asbestos-exposed subsets (AES), including 27 nonsmokers (NS), were evaluated and compared with 10 unexposed normal subjects. Data were collected on medical, smoking, and occupational histories, physical examination, spirometry, lung volumes, single-breath DLCO, chest films read by a "B" reader, and T-lymphocyte characterization in blood and BAL using flow cytometry analysis of monoclonal-antibody-treated cells. On average, AES were 47 yr of age and had 23 yr of asbestos exposure. Fifty-eight (48%) had pleural thickening, and seven (6%) had profusion greater than or equal to 1/0. In blood, asbestos-exposed NS had lower total and percent CD8 and lower total CD3 than did normal subjects. In BAL, asbestos-exposed NS had higher total CD3 than did normal subjects. Among AES, increased asbestos exposure was associated with increased percent CD8 in BAL and decreases in both percent lymphocytes and total CD8 in blood. Increase in CD4/CD8 ratio in BAL were associated with pleural thickening. In those seven with profusion greater than or equal to 1/0, there was increased percent CD4 in blood and decreased percent CD8 in BAL. These results suggest immune imbalance favoring helper-inducer T-cell subsets in association with asbestos exposure systemically and with pleural plaques in BAL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Imaging the pleura: sonography, CT, and MR imaging.

A variety of imaging techniques can be used to evaluate the pleura and the pleural space. Standard radiographs are the most common. In this article, however, we review the use of three other imaging techniques: sonography, CT, and MR imaging. Sonography allows easy identification of pleural fluid and loculation and differentiation from pleural masses; CT is best for characterizing location and composition of pleural masses; MR is somewhat limited, but is best for imaging superior sulcus carcinoma.

Diagnostic Imaging↗
PubMed1991

Occupational lung disease.

The pneumoconioses, extrinsic allergic alveolitis, lung damage due to irritant gases, fumes, and smoke constitute the occupational lung diseases that affect the lung parenchyma. The pneumoconioses are diseases resulting from the accumulation of dust in the lungs. The ILO has established a standardized system for classification of these pneumoconioses that includes both descriptions of diffuse lung opacities and pleural disease. The most common of the fibrogenic pneumoconioses are silicosis, CWP, and asbestosis. The former two entities are characterized radiographically by the presence of small rounded opacities or nodules in the lung parenchyma. Eggshell calcification may occur in lymph nodes, and eventually the diseases may be complicated by the development of large massive areas of fibrosis in the upper lung zones. Asbestosis, on the other hand, demonstrates small irregular or linear opacities usually confined to the bases of the lungs. It is associated with significant respiratory symptoms and disability. High resolution CT has proved useful in characterizing the parenchymal changes and also in identifying early disease in all of these entities. Berylliosis is a systemic disorder that in its chronic form produces granulomatous disease in the lungs. Radiographically it is characterized by the development of either small rounded or occasionally irregular linear opacities usually confined to the bases. Chemical pneumonitis results from exposure to toxic fumes. The acute reaction may produce diffuse lung injury characterized by air-space disease typical of pulmonary edema. In the chronic form, bronchiolitis obliterans supervenes. This usually is associated with either a normal radiograph or evidence of hyperinflation. Finally, hypersensitivity pneumonitis or extrinsic allergic alveolitis is a response of the lung to inhalation of antigens that may be present in the workplace. Either acute, subacute, or chronic disease may result. In the chronic form, a diffuse reticulonodular pattern with or without associated lymphadenopathy is characteristic.

Alveolitis, Extrinsic Allergic↗
PubMed1991

Imaging the airways. Computed tomography and magnetic resonance imaging.

Both CT and MRI are significant advances in the diagnostic imaging of the trachea and bronchi. Because of its ability to image the airways in cross section with high spatial and contrast resolution, CT has gained wide acceptance in the evaluation of tracheobronchial diseases. Although the spatial resolution of MRI is less than that of CT, MRI offers the advantages of multiplanar imaging, high contrast resolution without use of intravenous contrast agents, and absence of ionizing radiation. Although to date the role of MR in evaluating the trachea and bronchi has been limited, it may be anticipated that the list of indications will continue to expand with advancing technologic developments.

Bronchi↗
PubMed1990

Positional precautions in needle aspiration lung biopsy.

The authors performed 308 needle aspiration biopsies of parenchymal lung masses. The patients were then placed with the puncture site down for a period of at least 1 hour or until air leakage stopped. Coughing, talking, and activity were restricted. Complications included pneumothorax, at a rate of 25.0%, and chest tube placement, at a rate of 1.6%. In a subgroup of 262 patients who required only one pleural puncture at biopsy, a pneumothorax rate of 17.9% and a chest tube placement rate of 0.4% were encountered. When compared with a similar series of 143 control patients, significant reductions in both pneumothorax rate (P = .0004) and chest tube placement rate (P = .0001) were demonstrated.

Biopsy, Needle↗
PubMed1989

Coronary artery calcifications: significance of incidental detection on CT scans.

A scoring system was devised for the assessment of coronary artery calcifications apparent on computed tomographic (CT) scans, with width and length used to assess severity. The degree of calcification was compared with the presence of stenoses of 70% or greater at cardiac catheterization in 46 patients who underwent both studies. Although many significantly stenosed vessels showed no calcification, heavy calcifications had a high positive predictive value for significant disease. In a separate branch of the study, the perioperative cardiac morbidity and mortality were compared in 30 age- and sex-matched pairs of patients undergoing thoracotomy who did and did not have coronary calcifications on CT scans obtained before surgery. Patients with calcifications had a higher frequency of cardiac complications, including arrhythmias, ischemia, hypotension, myocardial infarction, and death.

Adult↗
PubMed1989

Pulmonary infections in the immunocompromised host.

The lung is an organ that is particularly susceptible to infection in the immunocompromised host. Patterns of involvement produced on the chest radiograph include (1) lobar or segmental consolidation; (2) nodules with rapid growth and/or cavitation; and (3) diffuse lung disease. There is a general correlation between the type of radiographic pattern and the microorganism producing the pneumonia. Invasive diagnostic procedures include needle aspiration, transbronchial, and open lung biopsy.

Bacterial Infections↗
PubMed1988

Image-guided pleural biopsies: indications, technique, and results in 23 patients.

Twenty-six pleural biopsies were performed on 23 patients over a 3-year period. Twenty-three biopsies were performed guided with ultrasound; one, with computed tomography; and two, with fluoroscopy. Indications for an image-guided pleural biopsy were (a) pleural masses or thickening that were either not seen on chest radiographs or seen only on one view and (b) small or loculated pleural effusions of unknown cause with no mass seen. If only pleural fluid was present, reverse bevel needles were used for biopsy (n = 15). If a discrete pleural mass or thickening was seen with cross-sectional imaging, standard (16-20 gauge) biopsy needles were used (n = 11). In the 23 patients, biopsy results were true positive in ten (nine with malignancy, one with tuberculous pleurisy), true negative in ten (confirmed either at subsequent thoracotomy or clinical follow-up), and false negative in three. Complications were few, with a significant pneumothorax occurring in two patients (8.7%). Image-guided biopsy of small pleural lesions and small pleural effusions can be performed by the radiologist who understands the special needles and techniques involved.

Biopsy, Needle↗
PubMed1986

CT of adenoid cystic carcinoma of the trachea.

The CT features of six cases of adenoid cystic carcinoma of the trachea are presented and compared to the bronchoscopic, surgical, and pathologic findings. CT accurately demonstrated extratracheal extension of tumor, which occurred in all six cases and which was not visible on standard chest radiographs. This information was helpful in planning the surgical approach. However, CT consistently underestimated the longitudinal extension of the lesion because of partial volume averaging and the tendency of adenoid cystic carcinoma to grow submucosally. CT was also a poor predictor of mediastinal organ invasion. Because recent advances in tracheal resection and carinal reconstruction have made many of these lesions resectable, CT is frequently used in the evaluation of the operability of patients with adenoid cystic carcinoma. However, its usefulness in this regard is limited, and conventional techniques such as standard tomography continue to play a role in preoperative assessment.

Adult↗