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Biomedical subjects

H MacMahon

Publications and source records attributed to H MacMahon.

At least 91 records · Page 5Linked to original sources
PubMed1987

The effect of previous thoracic surgery on gallium uptake in the chest.

To determine the frequency, average duration, and characteristic patterns of persistent gallium uptake caused by thoracotomy, serial postsurgical scans of 51 patients were reviewed. In each of these cases a thoracotomy had been performed for resection of lung cancer, and there had been no evidence of recurrent tumor for at least 2 yr following surgery. Postoperative gallium activity due to non-neoplastic postoperative changes occurred in 15 patients. Five of six patients scanned within 3 mo of surgery and six of 21 scanned 3 to 6 mo following surgery showed persistent uptake at the operative site. All 13 patients who had subsequent scans demonstrated eventual clearing. Activity persisted more than 18 mo postoperatively in only one patient. Patterns of gallium accumulation included both focal chest wall uptake at the incision site and diffuse pleural activity.

Gallium Radioisotopes↗
PubMed1986

Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance.

Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.

Analog-Digital Conversion↗
PubMed1986

Postoperative recurrence of lung cancer: detection by whole-body gallium scintigraphy.

The records were reviewed of 111 consecutive patients who had lung cancer resected and who were followed with serial postoperative whole-body gallium scans. Scans were obtained preoperatively at intervals of 3-6 months for about 1 year after surgery and subsequently at yearly intervals. The period of follow-up varied from 1 1/2 to 8 years. Of 55 patients who developed tumor recurrence, a gallium scan was the first indicator of recurrence in 11 (20%) and was judged helpful in confirming or localizing a recurrence in another 14 patients (25%). False-positive rates were determined from 175 postoperative scans in the other 56 patients who did not suffer recurrence. Of these 175 scans, 15 (9%) demonstrated abnormalities that were sufficiently suspicious that an additional diagnostic procedure, other than chest radiography, was performed for clarification. However, in no case did the gallium scan result adversely affect the management of the patient. Our data demonstrate that routine postoperative whole-body gallium scanning can facilitate early detection of recurrence in some cases. Judicious use of gallium scanning in cases with clinically suspected recurrence can enable prompt localization, diagnosis, and treatment of recurrent tumor.

Bone Neoplasms↗
PubMed1986

Regional accuracy of computed tomography of the mediastinum in staging of lung cancer.

To determine the regional accuracy of computed tomography of the mediastinum in staging lung cancer, we compared the results of preoperative computed tomographic staging to pathologic findings in lymph nodes taken at mediastinoscopy and/or thoracotomy in 61 patients. Twenty-two patients had adenocarcinoma, 24 had squamous cell carcinoma, eight had large cell tumors, and seven had small cell cancer or mixed cellular types. Sixteen patients had Stage I, eight had Stage II, and 37 had Stage III disease. Thirteen patients had mediastinoscopy only, and the remaining 48 patients had thoracotomy. Computed tomographic staging of the mediastinum as a whole had an accuracy of 88% with a negative predictive index of 96.1%. In examining the differential regional accuracy within the mediastinum we found results in the aortopulmonary window to be inferior to those of other regions, with an accuracy of 80% and a negative predictive index of 83.3%. The reliability of computed tomographic scan staging varied relative to cell type. The accuracy rate in adenocarcinoma was 94.7% compared to 70.6% in squamous cell carcinoma. Computed tomography is accurate for staging the mediastinum in lung cancer, and this accuracy holds over the regions of the mediastinum except the aortopulmonary window. Computed tomography is more accurate for staging adenocarcinoma than squamous cell cancer.

Adenocarcinoma↗
PubMed1985

Gallium accumulation in the stomach. A frequent incidental finding.

Accumulation of tracer by the stomach is a frequent incidental occurrence on gallium scans. Gastric concentration of Ga-67 equal to or greater than that seen in the liver was observed in approximately 10% of patients in a large series. Although a few of these patients had known or subsequently demonstrated gastric pathologic conditions, most had no clinically or radiographically identifiable gastric disease.

Gallium Radioisotopes↗
PubMed1984

Angioimmunoblastic lymphadenopathy: clinical and radiological features.

The authors describe the clinical and radiographic features in 7 patients with angioimmunoblastic lymphadenopathy (AIL) with dysproteinemia. This condition should be considered in any patient over 50 who presents with constitutional symptoms such as fever, weight loss, and malaise accompanied by involvement of the peripheral and hilar or mediastinal lymph nodes. Contrary to previous reports, the anterior mediastinal nodes may be involved. Intrapulmonary masses accompanied by clinical deterioration may indicate transformation to immunoblastic lymphoma. The gallium scans and radiographic appearance assist in the diagnosis, but lymph node biopsy is necessary in order to distinguish AIL from lymphoma.

Aged↗
PubMed1983

Diagnostic methods in lung cancer.

We feel that the guidelines described here reflect the state of the art at the time of writing (April 1982). The role of CT scanning is likely to evolve further and nuclear magnetic resonance (NMR) will probably play a significant role in the future. Experience, expertise, and equipment will vary from one hospital to another and thus rigid rules cannot reasonably be applied for the workup of suspected lung cancer. Ideally the diagnostic approach to an individual patient will be highly tailored, not only in regard to the nature of the pulmonary lesion, but also to his or her overall medical and social situation. We have found that a policy of early consultation between clinician and imaging specialist most readily facilitates effective use of available diagnostic resources.

Adult↗
PubMed1983

Opportunistic pulmonary aspergillosis with chest wall invasion. Plain film and computed tomographic findings.

A 37-year-old man with leukemia had the unusual complication of pulmonary aspergillosis eroding through adjacent bone. We were able to demonstrate this on computed tomography (CT) and even on the plain chest film. Bone invasion by an adjacent pulmonary lesion is most often attributed to other organisms or causes. This case demonstrates that aspergillosis must be added to the differential diagnosis of this finding. Recognizing this can be important for the prompt, appropriate treatment of opportunistic infections in the immunocompromised host.

Adult↗
PubMed1982

Bronchogenic carcinoma located in the aortic window. The importance of the primary lesion as a determinant of survival.

Thirty-four patients with an aortic window lesion were carefully staged with gallium scans and mediastinoscopy according to the TNM classification system for carcinoma of the lung. All were in Stage III. Twenty-five patients had non-oat cell carcinomas (15 squamous cell, eight adeno-, two large cell) and nine had oat cell carcinomas. Quantitative ventilation-perfusion lung scans were particularly helpful in verifying the subaortic location of the tumor by showing a less than 20% interference with pulmonary blood flow or ventilation secondary to left mainstem bronchus or pulmonary artery invasion. Decision for resectability in 13 Stage III M0 patients was based on the length of the uninvolved proximal left main pulmonary artery seen on pulmonary arteriogram. Eight patients (seven non-oat cell and one oat cell) had resection after radiation and prior to chemotherapy (after two cycles of chemotherapy and prior to radiation therapy for the oat cell) with a resultant survival rate better than those of M0 and M1 non-oat cell or oat cell patients without resection. The survival rates of nine non-oat cell M0 patients, nine non-oat cell M1 patients, and eight oat cell patients, all without resection, were not statistically different. This similarity in survival rates is explained by the observation that 38% of the non-oat cell M1, 71% of the non-oat cell M0, and 63% of the oat cell patients died from complications of their primary tumor. Patients with aortic window lesions, irrespective of their histology, have an extremely poor prognosis due to the high incidence of lethal complications of their primary tumor. Complete resection when feasible, as judged by pulmonary arteriography, provides the best control of the primary tumor and, as a consequence, gives longer survival.

Adenocarcinoma↗
PubMed1980

The benefits of open lung biopsy in patients with previous non-diagnostic transbronchial lung biopsy. A guide to appropriate therapy.

In a 17-month period, 20 immunosuppressed patients underwent transbronchial biopsy of the lung for diagnostic evaluation of a pulmonary infiltrate of unknown etiology. In 19 patients, the transbronchial biopsy was nondiagnostic. Thirteen of the 19 patients were critically ill and were referred for an open lung biopsy. Eleven (85 percent) of these 13 patients left the hospital after open lung biopsy and appropriate medical treatment. Two patients who were receiving mechanical ventilation at the time of open biopsy succumbed to the combination of their underlying disease and respiratory failure. There were no deaths directly attributed to the open lung biopsy. Of the six patients whose condition appeared stable and who did not undergo open lung biopsy, two died from unrecognized progress of their underlying malignant disease. The remainder recovered. We conclude that open lung biopsy is safe in and beneficial to the diagnosis and subsequent treatment of unknown pulmonary infiltrates in immunosuppressed patients who previously had a nondiagnostic fiberoptic transbronchial biopsy of the lung.

Adult↗
PubMed1979

Intrathoracic rib: radiographic features of two cases.

Two cases of intrathoracic rib are presented. In one of these the anomalous rib was not supernumerary, and the investing layers of pleura caused the rib to appear abnormally dense. The relevant literature is briefly reviewed.

Adult↗
PubMed1979

Erect scanning of pancreas using a gastric window.

A technique that can offer improved ultrasonic visualization of the pancreas is reported and evaluated. One hundred subjects were scanned in an erect sitting position with fluid-filled stomachs ("erect gastric window" technique). Conventional supine scans were initially performed in all cases; oblique, semierect, decubitus, prone, and standing positions with and without fluid-filled stomach were also evaluated. Compared with supine scans, the "erect gastric window" technique, occasionally supplemented by semierect, oblique, or decubitus views, provided significantly improved visualization of the pancreas in 93% of subjects. The nonvisualization rate was reduced from 19% to 1%.

Administration, Oral↗
PubMed1978

Multicentric tracheobronchial and oesophageal granular cell myoblastoma.

Two patients with multiple intrathorcic granular cell myoblastomas are described. In one case multiple tumours were present in the major airways and oesophagus. The patient presented with recurrent pulmonary infections and stridor due to airway obstruction. In the other case dysphagia caused by multiple oesophageal granular cell myoblastomas was the major symptom. Granular cell myoblastoma is a rare tumour of neurogenic origin with a characteristic histological appearance. The pattern of multiple tracheobranchial and oesophageal tumours is uncommon and forms the basis of this report.

Adult↗