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Biomedical subjects

P G Herman

Publications and source records attributed to P G Herman.

At least 37 records · Page 2Linked to original sources
PubMed1988

Preoperative localization of parathyroid adenomas.

During a 12-month period, 64 patients were operated on for primary hyperparathyroidism. Sixty-one had single adenomas and 3 had double adenomas. Preoperative imaging was used to localize the adenomas. Half of the patients (32 of 64) had magnetic resonance, thallium-201/technetium-99m subtraction scintigraphy, and high-resolution ultrasonography; the other 32 patients had 1 or 2 of the imaging modalities. Sensitivity and specificity of magnetic resonance imaging was 82 percent and 97 percent, respectively; the sensitivity and specificity of the other two modalities was 59 and 98 percent for subtraction scintigraphy and 73 and 98 percent for ultrasonography. The use of preoperative imaging facilitated surgical exploration, reduced operating time, and resulted in an increased number of successful operations. There were no negative explorations in this series as compared with 19 negative explorations (2.6 percent) in our prior experience with 720 operations.

Adenoma↗
PubMed1988

Optimization of computed tomography technique to demonstrate the fine structure of the lung.

The purpose of this investigation was to optimize the reconstruction algorithm and the slice thickness of computed tomography (CT) for the study of the fine structure of the lung. In 75 patients, we performed routine thoracic CT examination and obtained two high-resolution CT (HRCT) slices at the same level using the standard and bone algorithms, or using the slice thickness of 1.5 mm and 3.0 mm. Side-by-side comparison of the standard and bone images revealed that more branching of the small vessels and more small bronchi could be recognized on the bone image than on the standard image. Thickened bronchovascular bundles and interlobular septa were demonstrated more clearly on the bone image than on the standard image. There was no significant difference in the CT attenuation value between the standard and bone images. The difference between 1.5 mm and 3.0 mm images when demonstrating the small vessels and bronchi was minimal in such lesions as lymphangitis carcinomatosa and radiation fibrosis. Thus HRCT, with a slice thickness of 1.5 mm and 3.0 mm reconstructed by the bone algorithm, is suitable for the demonstration of the fine structure of the lung.

Humans↗
PubMed1986

High-resolution computed tomography of the pig lung.

Computed tomographic (CT)-anatomic correlation of the lung was performed on young Yorkshire pigs. After in vivo CT, the lungs were removed, fixed, and dried. The lung specimens were studied with CT and on several specimens, bronchography and arteriography also were done to establish the normal anatomy. Subsequently, the specimens were sliced at corresponding levels of the CT cuts and histology was done as needed. The lobules in the pig lung are very well demarcated. On the specimen radiographs with bronchography and in vivo CT in pulmonary edema, "sublobular units" can be readily identified that are rather uniform in size. On the in vivo CT with the standard algorithm, the relationship between the branches of the pulmonary artery and bronchus can be shown to the level of segmental bronchi. With the bone detail algorithm, vessels are clearly shown and lobar bronchi become visible. On in vivo CT, the lobular demarcations cannot be seen in the normal pig but clearly are visible in pulmonary edema. In cases of pulmonary edema, in addition to the lobules, the sublobular units and the sublobular bronchi, which measure .5 to .7 mm in diameter, also can be appreciated. Because of the well-developed pulmonary lobules and the uniformly sized sublobular units, the Yorkshire pig is potentially a good model for radiologic-pathologic correlation, particularly of airspace disease.

Animals↗
PubMed1985

Distribution and mechanism of uptake of 111InCl3 in a tumor model for lymph node metastases.

The localization of 111In activity in the tumor and draining lymph nodes of the H-4-II-E ACI rat hepatoma was investigated following the injection of 111In-chloride. In this tumor model, the tumors metastasize to the regional lymph nodes in male rats only. The following experiments were performed: (a) biodistribution of 111In; (b) correlation of 111In uptake with [3H]thymidine; (c) gamma camera imaging; (d) autoradiography; (e) iron competition and (f) binding of 131I-transferrin to H-4-II-E cells. Tumor-to-muscle ratios of 111In in males were 4.9:1 in the primary tumor and 9.1:1 in the metastatic lymph nodes 24 h post injection. In the lymph node metastases in the males, a significant correlation between 111In uptake and [3H]thymidine was observed (r = 0.737) suggesting that 111In uptake in the metastases is related to cellular proliferation. No such correlation was observed in either primary tumors (both male and female) or in the draining lymph nodes of the females. Metastatic lymph nodes in males could be detected in gamma camera images while draining nodes in females could not be delineated. Injection of ferric citrate prior to 111In administration resulted in a significant reduction of 111In uptake in the liver, spleen and tumor and increased the amount of activity recovered from the kidney. Measurements of the binding of 131I-labeled rat transferrin to H-4-II-E cells in vitro suggest that these cells display transferrin receptors.

Animals↗
PubMed1984

Differential diagnosis of mediastinal fluid levels visualized on computed tomography.

Mediastinal lesions containing three types of fluid levels were studied by computed tomography. Air-fluid, fat-fluid, and fluid-fluid levels were easily recognized and were caused by a colonic interposition, a cystic teratoma, and a hematoma, respectively. Computed tomography can be useful for detection and precise diagnosis of mediastinal lesions that contain fluid levels.

Adult↗
PubMed1983

Bedside chest radiography: diagnostic efficacy.

In order to evaluate the efficacy of bedside chest radiography, a prospective study was completed of 140 patients admitted to the surgical and medical intensive care units over a two-month period. A total of 1132 consecutive bedside radiographs was analyzed for malposition of tubes and lines and interval changes in the cardiopulmonary findings. The median number of bedside radiographs per patient was 0.7 per day. Endotracheal or tracheostomy tubes were present in 54% of all examinations; among these 12% were malpositioned. Central venous catheters were present in 47%; among these 9% were malpositioned. Interval changes regarding cardiopulmonary findings (pneumothorax, collapse, diffuse or focal infiltrate, effusion, and congestive heart failure) were present in 44% of the radiographs after the admission one. Overall there were new findings or changes affecting the patient's management present in 65% of the radiographs. The use of bedside radiography appeared to be appropriate.

Adult↗
PubMed1982

Pathologic patterns of Serratia marcescens pneumonia.

To characterize the pulmonary lesions caused by Serratia marcescens, the authors reviewed all autopsy-culture-proven cases of S. marcescens pneumonia occurring at their hospital between 1968 and mid-1980. In 16, S. marcescens was the only organism cultured from the lungs during life or at autopsy. This report describes primarily these pure infections. Two histopathologic reactions were seen. Nine non-neutropenic patients had acute, hemorrhagic bronchopneumonia, seven with microabscesses and two with larger cavities. In seven, distinctive vasculitis was apparent in vessels larger than 75 microns in diameter; intramural gram-negative rods were identified in two. Seven immunosuppressed patients had diffuse neutropenic pneumonitis resembling diffuse alveolar damage, with extensive intra-alveolar fibrinous exudates and pulmonary hemorrhage. In two patients, bacteria without cellular reaction were present. In patients with prolonged infections, focal areas of intra-alveolar organization and bronchiolitis obliterans accompanied both patterns. Since the incidence of nosocomial S. marcescens infection is increasing and since pneumonia caused by this organism is recognizable histologically, autopsy cultures positive for S. marcescens should not be disregarded.

Adult↗
PubMed1982

350 kV chest radiography has no diagnostic advantage: a comparison with 140 kV technique.

It has been suggested that a 350 kV technique will produce better chest radiographs than lower kilovoltage techniques. This is because the 350 kV x-ray spectrum provides better penetration of the overlying bony structures and results in a clearer delineation of the mediastinum. Fifty cases, containing 92 definite and significant abnormalities, were selected from a pool of 500 patients who had both 350 and 140 kV chest radiographs on the same day. The 50 paired films were studied at separate times by five experienced radiologists. The interpretations were analyzed for accuracy, significance, and confidence level; interpretation times and the utility of the lateral radiograph were also noted. When all the definitely and potentially significant abnormal findings were considered, the 350 kV films produced fewer true-positive reports and more false-positive reports than the 140 kV films. The receiver operating characteristic (ROC) curves, constructed from the observers' confidence ratings, were shifted toward less satisfactory performance for the 350 kV readings. When only statements about nodules and masses were considered, identical ROC curves were produced by the two techniques. Despite their potential advantages, the 350 kV films showed no diagnostic superiority over the 140 kV films.

False Negative Reactions↗
PubMed1981

Exogenous lipoid pneumonia.

Eleven patients with exogenous lipoid pneumonia are reported. A history of usage of oil was obtained in all, but in five only retrospectively after thoracotomy. The clinical presentations ranged from occasional cough to severe respiratory difficulties. The radiologic manifestations varied from a solitary lipoid granuloma and larger consolidations simulating carcinoma to extensive subacute bronchopneumonia. The definitive diagnosis was made by history and radiographic findings in three, by history and analysis of sputum or bronchial washings in two, and after thoracotomy in six.

Humans↗
PubMed1981

Resident film interpretations and staff review.

In this department 22% of examinations are interpreted independently by residents outside of normal hours. Staff radiologists review these studies in a process designed to train residents and assure appropriate radiologic consultation. The resident's written reports on 2,619 examinations were analyzed before and after staff review. Each film review session lasted an average of 1.1 hr. Potential changes were discussed in 9.1% of cases and mandated in 6.3%. About two-thirds of corrections were important enough to influence patient care. Correction rates declined significantly between the first and second/third years of residency; the proportion of clinically important changes also decreased. Omissions (false-negatives) were much more common than overcalls (false-positives). Residents correctly interpreted 89% of abnormal films and 96% of normal radiographs. Staff review resulted in a net improvement in interpretation of 4% of cases initially read by first-year residents and 2% by second- and third-year. The film review process provides opportunities for close resident-staff interaction and teaching and also ensures appropriate final reports.

Decision Making↗
PubMed1981

Interpretation of radiographs: effect of clinical history.

An effect of clinical information on interpretation of radiographs has been assumed, on the basis of experimental studies. To investigate this effect in a real-life setting, test films were included in the dialy work load of readers who were unaware that a study was being carried out. Eight subtle but unambiguous abnormalities (three lung nodules, lobar collapse, lung cyst, rib destruction, dilated esophagus, congestive heart failure) were included on the test films. For each abnormality there were four readings with a suggestive and four with a nonsuggestive clinical history. The readers were radiology residents and all interpretations were reviewed an sometimes altered by staff radiologists. There was a statistically significant (p less than 0.01) increase in the rate of true-positive readings in the presence of a suggestive as compared to nonsuggestive history: 16%-72% for residents' readings, 38%-84% for combined resident-staff readings. There was some concomitant increase in false positives.

Diagnostic Errors↗
PubMed1981

Sex-related differences in tumor progression associated with altered lymphocyte circulation.

Male and female ACI rats were inoculated with the syngeneic H-4-II-E hepatoma, and the natural history of the tumor, histopathology, and lymphocyte migration were studied. The tumor formed a.s.c. mass in all 16 males and in 22 of the 26 females given injections. In the males, tumors progressed, and all animals died with the mean survival time of 54 days. Complete tumor regression was observed in all but two females. In the females, there was prominent lymphocytic infiltration of the tumor, while males had no cellular reaction at the tumor site. The regional lymph nodes in males usually contained metastases and were nonreactive. The female lymph nodes did not contain metastases but contained many lymphocytes within the peripheral sinus and sinusoids. Six male-female pairs were castrated before tumor inoculation. Castration had no effect on the natural history or the etiology of the tumor. Comparing seven normal control male-female littermate pairs, there were no differences in lymphocyte accumulation in the lymph nodes 22 hr following injection of 51Cr-labeled syngeneic lymphocytes. In seven tumor-bearing male-female littermate pairs, there was a significant decrease in lymphocyte migration to the lymph nodes (p less than 0.001) in tumor-bearing males as compared to that in both their female littermates and control males. Depressed lymphocyte circulation in the males was associated with rapid progression of tumors resulting in the death of the animals. Unimpaired lymphocyte mobilization in the tumor-bearing females was associated with complete regression in most animals.

Animals↗
PubMed1980

Visibility and sharpness of lung structure at 90, 140, and 350 kV.

Human lung specimens containing a variety of lesions were radiographed at 90, 140, and 350 kV. Nodules less than 3 mm in diameter and linear shadows less than 0.3 mm in diameter were either not visible or poorly seen at 350 kV. Larger lesions were seen well with all three kilovoltages, although the interfaces were more distinct on the 90- and 140-kV views. The best images were obtained at 90, slightly worse at 140, and least satisfactory at 350 kV; in general, however, most features of the normal and diseased lung were readily seen at all three kilovoltages. The apparent degradation of the lung image at high kV levels may be explained by the large focal spot of the 350-kV system and the attenuation properties of high-energy photons.

Humans↗
PubMed1980

Serratia pneumonia.

The clinical and radiological manifestations were correlated with the necropsy findings in the lungs of 18 patients who died of Serratia marcescens infection. Ten died during a hospital epidemic affecting 74 patients. In 14, only Serratia was identified at autopsy; in 4, other organisms were also cultured. Ten patients had septicemia. The predominant radiological findings were focal bronchopneumonia in 13, lobar consolidation in 2, and diffuse nonhomogeneous infiltrates in 10. Small radiolucent areas within the infiltrates were seen in 5, a large pulmonary abscess in 1, and pleural effusion in 7. The predominant pathological findings were focal necrotizing bronchopneumonia (sometimes with microscopic abscesses) in 14 and diffuse hemorrhage in 3. Three patients had endocarditis and 3 others showed dissemination to the brain or kidneys.

Bronchopneumonia↗
PubMed1979

Non-Hodgkin lymphoma of the lungs.

Twenty-seven consecutive cases of pulmonary involvement by non-Hodgkin in lymphoma, including 2 cases of primary pulmonary disease, were anlyzed. The radiological manifestations of illness were divided into (a) nodular (subpleural, deep parenchymal, or perihilar), (b) pneumonic-alveolar (segmental or lobar), (c) bronchovascular-lymphangitic (central bronchovascular or diffuse lymphangitic), and (d) miliary-hematogenous. Histiocytic lymphoma was associated with infiltration of rapid onset in 6, cavitating nodules in 2, and diffuse lymphangitic dissemination in 9. Of 16 patients with lymphocytic lymphoma, 7 had lobar or segmental alveolar involvement.

Adult↗
PubMed1979

Arteriovenous shunting in the lymph node before and after antigenic stimulus.

We have assessed the effects of antigenic stimulation on the regional blood flow of the lymph node. In seventeen New Zealand white rabbits, the regional blood flow to the popliteal lymph nodes was determined using 9 and 15 micron microspheres at 16, 40, and 144 h following antigen administration. The regional blood flow in the resting lymph node measured with 15 micron spheres was 0 . 46 +/- 0 . 07 ml g-1 min-1, with 9 micron spheres 0 . 26 +/- 0 . 03 ml g-1 min-1. There was a significant 'differential flow' (the difference in blood flow between the experimental and control nodes) measured with 15 micron spheres (P less than 0 . 05). This increase in blood flow was larger early (16 h) than late (144 h) following antigen administration (P less than 0 . 01). There was significant (P less than 0 . 05) 'shunt flow' (the difference in blood flow measured with 15 micron and 9 micron spheres) in the lymph node, with more shunting early (16 h) than late (144 h) following antigen administration. No significant shunting was seen in the kidney or thigh muscle. Thus, we have established: (1) a significant increase in blood flow following antigenic stimulus; (2) shunting of 9 micron microspheres in the resting popliteal lymph node; (3) increased shunting following antigenic stimulus; and (4) that the increase in nodal blood flow was, to a large extent, secondary to increased shunt flow. Both the increased blood flow and the shunting shortly after antigenic stimulus may be important in the evolution of the immune response.

Animals↗