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Biomedical subjects

J R Muhm

Publications and source records attributed to J R Muhm.

At least 19 recordsLinked to original sources
PubMed2003

Surgical pathology of granulomatous interstitial pneumonia.

Agranulomatous interstitial pneumonia is a form of diffuse lung disease in which granulomas are a component of the histologic findings. The differential diagnosis is quite broad, but most cases represent examples of either sarcoidosis, diffuse granulomatous infections, or hypersensitivity pneumonitis. "Hot tub lung" is a recently described form of granulomatous interstitial pneumonia that appears to have some features of diffuse infections and some features of hypersensitivity pneumonitis. The pathologist's approach to these conditions can be facilitated by giving careful attention to the anatomic distribution of the granulomas, the qualitative features of the granulomas, and the histologic changes in the lung tissue around and away from the granulomas. These features, along with the results of cultures and special stains for micro-organisms and clinical and radiologic correlation allow for a diagnosis in the vast majority of cases.

Diagnosis, Differential↗
PubMed2000

Lung nodule enhancement at CT: multicenter study.

PURPOSE: To test the hypothesis that absence of statistically significant lung nodule enhancement (< or =15 HU) at computed tomography (CT) is strongly predictive of benignity. MATERIALS AND METHODS: Five hundred fifty lung nodules were studied. Of these, 356 met all entrance criteria and had a diagnosis. On nonenhanced, thin-section CT scans, the nodules were solid, 5-40 mm in diameter, relatively spherical, homogeneous, and without calcification or fat. All patients were examined with 3-mm-collimation CT before and after intravenous injection of contrast material. CT scans through the nodule were obtained at 1, 2, 3, and 4 minutes after the onset of injection. Peak net nodule enhancement and time-attenuation curves were analyzed. Seven centers participated. RESULTS: The prevalence of malignancy was 48% (171 of 356 nodules). Malignant neoplasms enhanced (median, 38.1 HU; range, 14.0-165.3 HU) significantly more than granulomas and benign neoplasms (median, 10.0 HU; range, -20.0 to 96.0 HU; P < .001). With 15 HU as the threshold, the sensitivity was 98% (167 of 171 malignant nodules), the specificity was 58% (107 of 185 benign nodules), and the accuracy was 77% (274 of 356 nodules). CONCLUSION: Absence of significant lung nodule enhancement (< or = 15 HU) at CT is strongly predictive of benignity.

Adult↗
PubMed2000

Lung nodules: dual-kilovolt peak analysis with CT--multicenter study.

PURPOSE: To test the following hypothesis: The greater the increase in the mean computed tomographic (CT) number of a radiologically indeterminate lung nodule from the CT number on a 140-kVp CT image to that on an 80-kVp CT image, the more likely the nodule is benign (ie, contains calcium). MATERIALS AND METHODS: Two hundred forty indeterminate lung nodules were prospectively studied at four institutions: Mayo Clinic Scottsdale, Ariz (n = 160); Mayo Clinic Rochester, Minn (n = 50); Shiga Health Insurance Hospital, Otsu, Japan (n = 25); and Duke University Medical Center, Durham, NC (n = 5). Of the 240 nodules, 157 met the entrance criteria for this study and had a diagnosis. All nodules included were solid, 5-40-mm diameter, relatively spherical, homogeneous, and without visible evidence of calcification or fat. Each nodule was evaluated by using 3-mm-collimation, nonenhanced CT scans with both 140- and 80-kVp x-ray beams. RESULTS: There were 86 (55%) benign and 71 (45%) malignant nodules. The median increase in the nodule mean CT number from the CT number on 140-kVp images to that on 80-kVp images was 2 HU for benign nodules and 3 HU for malignant nodules. This difference was not statistically significant. The area under the receiver operating characteristic curve was 0.505. CONCLUSION: Dual-kilovolt peak analysis with current CT technology does not appear to be helpful in the identification of benign lung nodules.

Adult↗
PubMed1999

Quality-of-service improvements from coupling a digital chest unit with integrated speech recognition, information, and picture archiving and communications systems.

Speech recognition reporting for chest examinations was introduced and tightly integrated with a Radiology Information System (RIS) and a Picture Archiving and Communications System (PACS). A feature of this integration was the unique one-to-one coupling of the workstation displayed case and the reporting via speech recognition for that and only that particular examination and patient. The utility of the resulting, wholly integrated electronic environment was then compared with that of the previous analog chest unit and dedicated wet processor, with reporting of hard copy examinations by direct dictation to a typist. Improvements in quality of service in comparison to the previous work environment include (1) immediate release of the patient, (2) decreased rate of repeat radiographs, (3) improved image quality, (4) decreased time for the examination to be available for interpretation, (5) automatic hanging of current and previous images, (6) ad-hoc availability of images, (7) capability of the radiologist to immediately review and correct the transcribed report, (8) decreased time for clinicians to view results, and (9) increased capacity of examinations per room.

Humans↗
PubMed1991

Screening for lung cancer. A critique of the Mayo Lung Project.

The National Cancer Institute of the United States recently sponsored three large-scale, randomized controlled trials of screening for early lung cancer. The trials were conducted at the Johns Hopkins Medical Institutions, the Memorial Sloan-Kettering Cancer Center, and the Mayo Clinic. Participants were middle-aged and older men who were chronic heavy cigarette smokers and thus at high risk of developing lung cancer. Screening procedures were chest radiography and sputum cytology, the only screening tests of established value for detecting early stage, asymptomatic lung cancer. In the Hopkins and Memorial trials the study population was offered yearly chest radiography plus sputum cytology every 4 months. The control population was offered yearly chest radiography only. In these trials the addition of sputum cytology appeared to confer no lung cancer mortality rate advantage. The Mayo Clinic trial compared offering chest radiography and sputum cytology every 4 months to offering advice that the two tests be obtained once a year. This trial demonstrated significantly increased lung cancer detection, resectability, and survivorship in the group offered screening every 4 months compared with the control group. However, there was no significant difference in lung cancer mortality rate between the two groups. The statistical power of these trials was somewhat limited. Nevertheless, results do not justify recommending large-scale radiologic or cytologic screening for early lung cancer at this time.

Clinical Trials as Topic↗
PubMed1989

Solitary pulmonary nodules: evaluation with a CT reference phantom.

The Zerhouni computed tomographic (CT) reference phantom was used to study 112 solitary pulmonary nodules that were indeterminate with plain tomography. Of the 112 nodules, 33 were more attenuating than the reference phantom and 79 less attenuating. One patient with a previous endometrial malignancy had a pulmonary metastatic lesion that was more attenuating than the reference phantom, presumably due to microscopic calcification. The nodule in the other 32 cases was benign, as determined from follow-up studies of up to 4.5 years or by means of surgical sampling (two patients). Among the 79 nodules that were less attenuating than the reference phantom, 26 were malignant, 22 were benign, and 31 were followed up for up to 4.5 years with no evidence of malignancy. In this series, the CT reference phantom proved to be a useful adjuvant to plain tomography in patients whose nodules were uncalcified and had an indeterminate shape.

Female↗
PubMed1987

Computed tomography of benign mature teratomas of the mediastinum.

The computed tomography (CT) findings of five benign, mature teratomas of the anterior mediastinum collected during a ten-year period are described, and their case histories are reviewed. Three of the five were primarily cystic, with only small soft tissue components. One of the five contained equal cystic and solid elements. All cysts had a higher attenuation than water. Three tumors contained small foci of dense calcification or ossification. Only two contained fat. Computed tomography accurately predicted the presence of adherence to adjacent structures in all five. Four of five patients were less than 22 years of age, and benign teratoma of the mediastinum was not a common neoplasm at any age. The origin and pathology of germ cell tumors of the mediastinum are briefly reviewed.

Adolescent↗
PubMed1987

Solitary pulmonary opacities: plain tomography.

New or enlarging solitary pulmonary opacities in 502 patients were evaluated with a plain tomographic procedure. Repeat chest radiographs in 64 patients and tomograms in 115 patients showed that the opacities were not nodules but were due to pneumonitis, rib lesions, thickened pleura, or another benign finding. Tomography demonstrated 85 of the 323 nodules to be calcified granulomas. The shape of the 238 uncalcified nodules was classified as benign, malignant, or indeterminate. None of the 38 nodules classified as benign proved to be malignant during 2 years of follow-up. Of the 33 nodules with a malignant shape, 31 proved to be malignant at operation or clinical follow-up. Among the 167 nodules characterized as indeterminate, 128 were benign and 39 were malignant on follow-up. In this series, the plain tomographic procedure, including fluoroscopy and repeat chest radiography, allowed an accurate diagnosis in 67% of solitary pulmonary opacities.

Adolescent↗
PubMed1986

Diffuse malignant mesothelioma of pleura. Diagnosis and survival in 92 cases.

Clinical, radiographic, surgical, and pathologic findings and survival in 92 patients with diffuse malignant mesothelioma (DMM) of the pleura who were examined at the Mayo Clinic between 1950 and 1980, were studied retrospectively. With the use of defined criteria and ordinary tissue stains, the 92 cases were classified into the following histologic subtypes: purely epithelial, 42 cases; mixed, 29 cases; and sarcomatous, 21 cases. Eight of the sarcomatous cases were desmoplastic. Median survivals were 12, 5, and 3 months for the patients in the epithelial, mixed, and sarcomatous groups, respectively. Survival was significantly longer for patients with epithelial DMM. Women survived longer than men but more often had epithelial DMM. Early disease manifested as multiple discrete pleural nodules, predominantly on the parietal pleura. However, nine patients had a dominant mass. Radiographic signs especially suggestive of DMM were nodular pleural thickening, irregular thickening of interlobar fissures, a dominant mass, or decreased volume of the affected hemithorax.

Adult↗
PubMed1986

Lung cancer screening: the Mayo program.

The National Cancer Institute has sponsored three randomized controlled trials of screening for early lung cancer in large, high-risk populations to determine whether lung cancer detection can be improved by adding sputum cytological screening every 4 months to chest roentgenography done either yearly or every 4 months; and lung cancer mortality can be significantly reduced by this type of screening program, followed by appropriate treatment. Results of the three trials suggest that sputum cytology alone detects 15% to 20% of lung cancers, almost all of which are squamous cancers with a favorable prognosis; and chest roentgenography may be a more effective test for early-stage lung cancer than previous reports have suggested. Nevertheless, results of the randomized trial conducted at the Mayo Clinic showed that offering both procedures to high-risk outpatients every 4 months conferred no mortality advantage over standard medical practice that included recommended annual testing.

Clinical Trials as Topic↗
PubMed1986

CT of the pulmonary nodule: a cooperative study.

To evaluate the role of computed tomography (CT) in the investigation of pulmonary nodules, a special reference phantom that enabled CT densitometric measurements independent of variations between scanners and patients was used in ten institutions. A total of 384 nodules not considered calcified by conventional methods were examined; 118 (31%) proved to be benign, and in 65 of these (55%), unsuspected calcification was demonstrated. In 28 of the 65, definite calcification could be identified on thin-section CT scans by simple inspection of the scans at narrow windows. In the remaining 37, presence of calcification could not be clearly established without comparison with the reference CT number from the calibration phantom. CT was most effective in establishing the benignancy of nodules 3 cm or less in diameter and those with discrete or smooth margins. CT rarely yields a confident diagnosis of benign disease in larger nodules and in those with irregular or spiculated borders. After review of prior spot radiographs, low kilovolt peak spot radiographs, and conventional tomograms, the authors conclude that thin-section CT aided by a reference phantom in equivocal cases should be an integral part of the diagnostic approach to the pulmonary nodule.

Adult↗
PubMed1985

Current place of plain-film tomography in chest disease.

Plain-film tomography is a quick, accurate, and inexpensive procedure that is valuable for the evaluation of two common problems in chest radiology--the solitary pulmonary nodule and the hilus that is questionably abnormal. An accurate diagnosis can be made in most patients with a solitary pulmonary nodule so that appropriate management can be undertaken. If the diagnosis of an indeterminate nodule is made, further evaluation with computed tomography, transthoracic needle aspiration biopsy, surgery, or careful radiographic follow-up can be suggested. Hilar tomography can determine whether the appearance of the hilus on the chest radiograph is due to prominent but normal vessels, an enlarged pulmonary artery, enlarged hilar lymph nodes, or a pulmonary mass.

Humans↗
PubMed1985

Malignant germ cell tumors of the mediastinum.

A review of 56 cases of primary malignant germ cell tumors of the mediastinum revealed that, as with benign teratomas, the tumors occurred in young adults (mean age 29 years) but that the sex distribution differed (86% male and 14% female). A single germ cell element was found in 37 (66%) of the tumors, and various combinations were present in the remaining 19 (34%). The tumors were classified among five recognized types of germ cell tissues. There were 24 seminomas (22 pure and two with mature teratomas), 17 embryonal carcinomas (nine pure and eight with mixtures), five teratomas, seven choriocarcinomas (three pure and four with mixtures), and three pure yolk sac tumors. Most (86%) of the patients were symptomatic at the initial examination, with chest pain, cough, and loss of weight being the most frequent presenting symptoms. The standard posteroanterior and lateral roentgenograms were the most helpful diagnostic tool, showing evidence of an anterior mediastinal mass in 53 patients. The diagnosis was established by surgical exploration of the mediastinum or by biopsy of a lymph node in 55 patients. Of the 55, 24 (43.6%) had complete resection of the tumor and 31 (56.4%) had incomplete resection or biopsy alone. The overall prognosis for mediastinal germ cell tumors is poor, partly because the tumors are far advanced at the time of diagnosis but also because some of the tumors that contain embryonal cell carcinoma, choriocarcinoma, and yolk sac elements are very aggressive. Factors that were prognostic in patients with seminoma--such as age, presence of the superior vena caval syndrome, lymphadenopathy, evidence of hilar disease on the chest roentgenogram, and resectability--were not predictive in patients with other types of malignant germ cell tumors. Although aggressive combination chemotherapy may represent a significant treatment modality for nonseminomatous mediastinal tumors, the present study spanned many years in which no chemotherapy was available. Patients in the later years of the study received combination chemotherapy with various treatment regimens. No conclusions concerning specific chemotherapy, therefore, can be derived from this study.

Adolescent↗
PubMed1984

Mediastinal masses. Clues to interpretation of radiologic studies.

The best approach to evaluation of a mediastinal mass begins with a history and a physical examination that are oriented toward discovery of evidence of compression or obstruction to any of the mediastinal organs. Currently, the most efficient radiographic approach, after the plain chest roentgenogram, is computed tomography of the thorax, supplemented as needed by selected plain tomograms or a barium swallow examination. Unless the mass is definitely a benign lesion of no consequence, such as a pericardial fat pad, thoracotomy by an experienced thoracic surgeon is usually necessary to make a specific diagnosis and excision is performed if possible.

Adolescent↗
PubMed1984

Early lung cancer detection: results of the initial (prevalence) radiologic and cytologic screening in the Mayo Clinic study.

The initial (prevalence) radiologic and cytologic screening for lung cancer in the Mayo Clinic study (Mayo Lung Project) involved 10,933 outpatients. All were men at high risk for lung cancer, but none were suspected of having it when they entered the Mayo Clinic. Screening identified 91 lung cancers (8.3 per 1,000 screened). Nearly two thirds of the prevalence lung cancers were detected by chest roentgenography alone. Half of these cancers were resected. Only a fifth of the cancers were detected by sputum cytologic examination alone; however, all but 1 of these were resected. Compared with a group of lung cancers encountered in contemporary clinical practice at the Mayo Clinic, the prevalence cancers were more than twice as likely to be (1) resectable, (2) postsurgical Stage I or II (AJCC), and (3) associated with survival 5 yr after treatment.

Adenocarcinoma↗
PubMed1983

Lung cancer detected during a screening program using four-month chest radiographs.

Ninety-two lung cancers were detected in the Mayo Lung Project in patients undergoing chest radiography every four months for screening. Fifty patients had a peripheral nodule, 16 had a perihilar nodule, 20 had hilar or mediastinal enlargement, and six had pneumonitis. The peripheral cancers grew slowly. Ninety per cent were visible in retrospect for months or even years. Despite this, 70% of the peripheral cancers were classified as postsurgical American Joint Committee (AJC) Stage 1. The central cancers grew rapidly, usually presenting as hilar or mediastinal enlargements after normal findings on the previous radiograph obtained four months earlier. Most were classified as AJC Stage 3 tumors.

Adenocarcinoma↗
PubMed1983

Computed tomography of the thorax. Current perspectives.

With improvement in computed tomography (CT) technology, including faster scanning and images with better detail, the indications for CT of the thorax have expanded. In many instances, data collected on earlier-generation scanners no longer apply. This report is an update of CT scanning of the thorax and includes information on the role of CT in diagnosis when specific clinical syndromes and diseases are suspected. It also addresses controversial subjects, such as the role of CT scanning in the staging of bronchogenic carcinoma and the evaluation of the solitary pulmonary nodule, as well as suggesting guidelines for deciding when a CT scan of the thorax is indicated.

Aortic Dissection↗