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Biomedical subjects

W B Gefter

Publications and source records attributed to W B Gefter.

At least 55 records · Page 3Linked to original sources
PubMed1994

Pulmonary aspergillosis in patients with AIDS. Clinical and radiographic correlations.

OBJECTIVE: To evaluate the clinical and radiographic features of pulmonary aspergillosis as they present in AIDS patients; in particular, to determine similarities and differences between Aspergillus infection in patients with AIDS vs those without AIDS. SUBJECTS AND METHODS: Six new cases of confirmed or probable pulmonary aspergillosis were discovered during a search of hospital records. These are reviewed with 30 previously reported cases with special attention to radiographic appearance of disease and how radiographic appearance influences clinical outcome. RESULTS: Symptoms of pulmonary aspergillosis in AIDS were nonspecific, most often including fever, cough, and dyspnea, and less commonly, chest pain or hemoptysis. Major risk factors for the development of pulmonary aspergillosis in patients with AIDS were steroid administration and neutropenia. Neutropenia was often a complication of therapies for AIDS, in particular, ganciclovir and zidovudine. Radiographic appearance of disease could be divided into three general categories. One third of the patients (13/36) presented with cavitary upper lobe disease resembling noninvasive or chronic necrotizing aspergillosis. Fatal hemoptysis occurred in 42 percent of patients with this form of disease. Twenty-two percent (8/36) of the cases presented as a nondescript focal alveolar opacity similar to invasive aspergillosis. In several patients, the focal infiltrate remained stable for several months, a feature that is unusual for aspergillosis in non-AIDS patients. The air crescent sign was present in none of the 36 reported cases. Patients with only focal disease had the best prognosis of patients with pulmonary aspergillosis. Bilateral alveolar or interstitial disease similar to invasive aspergillosis was present in 23 percent (9/36) of the patients. Bilateral disease appears to be a marker for disseminated infection and was associated with a high mortality due to aspergillosis. Two new forms of bronchial aspergillosis (5/36 cases) have been described previously. These patients presented with either obstructing fungal casts or bronchial pseudomembranes demonstrated bronchoscopically. In some patients with the bronchial forms of aspergillosis, transient alveolar opacities were seen on chest radiographs. These opacities may represent regions of atelectasis due to airway obstruction. One patient who had bilateral pneumothoraces without parenchymal opacities did not correspond to any of the three previously mentioned categories. Mortality due to aspergillosis was greater than 50 percent among AIDS patients. Death was subsequent to fatal hemoptysis or widespread pulmonary or systemic infection. CONCLUSION: Unlike other risk groups that tend to contract only one form of pulmonary aspergillosis, AIDS patients can develop the whole spectrum of aspergillosis-related pulmonary disorders, including chronic cavitary, invasive, and bronchial forms of aspergillosis. Clinical symptoms are nonspecific and major risk factors include neutropenia, which is often a side effect of various therapies for AIDS, and steroid administration. Patients with the chronic cavitary form of disease have an unusually high mortality due to fatal hemoptysis. Patients with bilateral pulmonary infiltrates and aspergillosis have a high mortality due to disseminated infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Evaluation of pulmonary vascular anatomy and blood flow by magnetic resonance.

Rapidly evolving magnetic resonance (MR) imaging techniques provide noninvasive approaches to evaluating morphology and quantitative physiologic information about blood flow in the pulmonary circulation. Important clinical applications currently include the preoperative and postoperative evaluation of congenital abnormalities, assessment of vascular involvement by extrinsic and intrinsic tumors, identification of central thromboemboli, and diagnosis of vascular lung lesions. Ongoing refinements in pulmonary MR angiography may make it possible to use the technique for the noninvasive detection of acute pulmonary emboli in the near future. Quantitative measurements based upon MR flow-encoding sequences are promising for the evaluation of patients with abnormal degrees or distributions of pulmonary blood flow, for example, those with unilateral lung transplants or pulmonary arterial stenoses. MR contrast agents currently under development also show promise for quantitative measurements of regional pulmonary ventilation and perfusion. The coupling of high-resolution anatomic and functional images renders MR a uniquely attractive and powerful method for evaluating the pulmonary vasculature.

Humans↗
PubMed1993

Suspected pulmonary embolism: prospective evaluation with pulmonary MR angiography.

PURPOSE: To prospectively evaluate three magnetic resonance (MR) imaging techniques for detection of pulmonary embolism. MATERIALS AND METHODS: Eighteen patients in whom the presence of acute or chronic pulmonary emboli was suspected underwent examination with the following pulse sequences: cardiac-gated spin echo, cine spatial modulation of magnetization, and two-dimensional time-of-flight pulmonary breath-hold (PBH) MR angiography. Three radiologists independently and blindly reviewed each case and graded a total of 518 arterial segments for each pulse sequence with a continuous scale of 0%-100% for likelihood of pulmonary embolism. RESULTS: The overall sensitivity of PBH MR angiography for detection of acute pulmonary emboli was 0.85; for chronic emboli, which were smaller in anteroposterior (AP) diameter, the overall sensitivity was 0.42. Emboli larger than 1 cm in AP diameter were typically identified with > 75% confidence with all pulse sequences. CONCLUSION: Acute pulmonary emboli greater than 1 cm in AP diameter were as accurately identified on PBH MR angiograms obtained in 15 seconds as they were on MR images obtained with longer pulse sequences not dependent on breath holding.

Acute Disease↗
PubMed1993

Dynamic imaging of the upper airway during respiration in normal subjects.

The present study was conducted to determine the effects of quiet respiration on upper airway caliber in 15 normal subjects by using cine computed tomography. The cine computed tomography (Imatron) scanner was programmed to obtain 8-mm-thick axial slices every 0.4 s during inspiration and expiration at four anatomic levels, from the nasopharynx to the retroglossal region. Airflow (pneumotachograph) was measured, and tidal volume was obtained by integration. Upper airway area, determined by an objective edge detection algorithm, was plotted as a function of tidal volume to generate a loop describing upper airway area changes at each level during a respiratory cycle. The results demonstrate a 17% change in airway size across all anatomic levels during respiration. The maximum upper airway cross-sectional area at all four anatomic levels was significantly greater during expiration than during inspiration. Other major findings include 1) upper airway cross-sectional area decreases slightly during early inspiration, enlarges toward end inspiration, and is larger at end inspiration than at the beginning of inspiration; 2) upper airway cross-sectional area enlarges from end inspiration to the first point in expiration; the airway enlarges further, reaching its maximum early in expiration, and then narrows toward end expiration; and 3) the changes in upper airway dimensions during resting tidal breathing are greater in the lateral than in the anteroposterior direction. The data suggest that during inspiration, the action of negative intraluminal pressure may be largely balanced by the action of the upper airway dilator muscles, whereas during expiration, positive intraluminal pressure produces expansion of the upper airway.

Adult↗
PubMed1993

Dynamic upper airway imaging during awake respiration in normal subjects and patients with sleep disordered breathing.

The effects of respiration on upper airway caliber were studied using cine computed tomography (CT) in 15 normal subjects, 14 snorer/mildly apneic subjects, and 13 patients with obstructive sleep apnea. All subjects were scanned in the supine position during awake nasal breathing. Eight-millimeter-thick axial slices were obtained at four anatomic levels from the nasopharynx to the retroglossal region every 0.4 s during a respiratory cycle. Tidal volume measured from an integrated pneumotachograph signal was correlated with slice acquisition during inspiration and expiration to generate loops comparing upper airway area and tidal volume. In all three subject groups and at all anatomic levels studied, there were significant dimensional changes in upper airway caliber during the respiratory cycle. The major findings in this investigation include: (1) the upper airway was significantly smaller in apneic than normal subjects, especially at the retropalatal low and retroglossal anatomic levels; in apneic patients the airway had an anterior-posterior configuration unlike the normal airway, which had a horizontal configuration with the major axis in the lateral direction; (2) in all three subject groups, little airway narrowing occurred in inspiration, suggesting that the action of the upper airway dilator muscles balanced the effects of negative intraluminal pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Asbestos-related chest diseases: plain radiographic findings.

In summary, there are a wide range of pulmonary manifestations seen in asbestos-exposed individuals from pleural and parenchymal fibrosis to pleural and parenchymal malignancy. The chest roentgenogram has assumed an important role in the detection and surveillance of asbestos-related pleural and parenchymal changes.

Asbestos↗
PubMed1992

The spectrum of pulmonary aspergillosis.

Aspergillus species can produce a wide range of pulmonary disorders. Classically, pulmonary aspergillosis has been categorized into invasive, saprophytic, and allergic forms, all of which differ in their manifestations and therapy. More recently, however, other types of infection by this fungus have been recognized that do not fit into these traditional categories; an example is semi-invasive (chronic necrotizing) aspergillosis. In fact, these forms have features that are intermediate between those of the invasive and saprophytic types. The various types of aspergillosis can be regarded as constituting a continuous spectrum, ranging from invasive disease in the severely immunosuppressed patient to hypersensitivity reactions such as allergic bronchopulmonary aspergillosis (and bronchocentric granulomatosis) in the hyperreactive patient. Between these extremes are chronic necrotizing disease seen in midly immunocompromised hosts, and the noninvasive aspergilloma, which is due to saprophytic growth within a previously diseased area of lung in an otherwise normal host. Other intermediate forms may be encountered, their behavior being determined by the host immune status in combination with the underlying lung morphology. The radiographic and clinical features of these various forms of pulmonary aspergillosis are reviewed, including the more recently reported forms of infection such as Aspergillus tracheobronchitis and aspergillosis associated with acquired immunodeficiency syndrome and cystic fibrosis. The proposed concept of a disease spectrum is emphasized.

Aspergillosis↗
PubMed1992

Thymoma mimicking a thyroid mass.

Two cases of ectopic cervical thymoma are presented. These cases both manifested as mass lesions at the thoracic inlet, displacing the trachea, and were originally misdiagnosed as thyroid masses. The masses had clinical features similar to those previously reported for cervical thymoma: preponderance in women, benign clinical course, and absence of myasthenic symptoms.

Aged↗
PubMed1992

Acute pulmonary edema induced by overdosage of phenothiazines.

Three schizophrenic adults with previous histories of using phenothiazine derivatives developed acute pulmonary edema after taking large amounts of these drugs. The clinical manifestations included coma (three), hypothermia (two), tachycardia (two), miosis (two) and hypotension (one). All three patients underwent gastric lavage and were treated supportively. The fulminant pulmonary edema in the three cases resolved within 18 to 40 h. The etiology of pulmonary edema following overdosage of phenothiazines remains unknown. The authors hypothesize that the most likely pathogenesis is a drug-induced neurogenic pulmonary edema resulting from a disturbance of hypothalamic function.

Acute Disease↗
PubMed1992

Thymoma--report of 71 cases and a review.

Of the 71 cases of thymoma reviewed, 31 were benign and 40 were malignant. Associated syndromes were common--myasthenia gravis 51% (36/71), red cell aplasia 3%, hypogammaglobulinemia 4%, mucocutaneous candidiasis 1%, and a number of other autoimmune diseases and neoplasms. These were almost equally distributed among benign and malignant tumors. A plain radiograph showing diffuse involvement of the mediastinum always indicates invasive (malignant) thymoma, while a localized pattern usually suggests a benign lesion (25 of 39 cases). Computerized tomography or MRI often gives additional information. An optimistic approach and aggressive radiotherapy are indicated in patients whose only metastatic disease is to one pleural space; prolonged survival is frequent in this group.

Adolescent↗
PubMed1991

Evaluation of the upper airway in patients with obstructive sleep apnea.

Multiple methods have been used to study the structure and physiological behavior of the upper airway (UA) in patients with obstructive sleep apnea (OSA). Valuable information may be obtained from the physiologic measurement of pressure and resistance along the UA, as well as from imaging techniques that include: direct or fiberoptic visualization, cephalometric roentgenograms, fluoroscopy, acoustic reflection, computerized tomography, and magnetic resonance imaging. This review summarizes the information that each of these methods has contributed to our understanding of the UA. The results obtained with these different methodologies have generally been complementary with structural narrowing being identified in the majority of patients with OSA. This narrowing is usually focal and located in the velopharyngeal or retropalatal segment of the UA. This is also the predominant site of initial UA collapse. Although obesity with enlargement of soft tissue structures is considered the predominant mechanism leading to UA narrowing, abnormal craniofacial development on a genetic or developmental basis plays an important contributory role.

Airway Obstruction↗
PubMed1991

Drug-induced pulmonary disease: an update.

The review provides an update of drug-induced pulmonary disorders, focusing on newer agents whose effects on the lung have been studied recently. Included among these drugs are cyclosporine, cytosine arabinoside (Ara-C), amiodarone, interleukin-2 (IL-2), OKT3, tricyclic antidepressants, and bromocriptine. A brief review of the most common cytotoxic and noncytotoxic agents causing pulmonary toxicity is also included.

Antibodies, Monoclonal↗
PubMed1991

Magnetic resonance approaches to the evaluation of pulmonary vascular anatomy and physiology.

MR imaging offers the potential for combined anatomic and flow-related information about the pulmonary circulation. Although conventional spin-echo sequences have provided an accurate and noninvasive means of evaluating the anatomy of the central pulmonary arteries and veins, newer MR techniques--including cine MR, velocity-encoded phase-contrast scans, spatial modulation of magnetization (SPAMM), fast scan techniques with breath-holding, and echo planar imaging in combination with computer-based post-processing--are providing physiological information superimposed on the anatomic maps. This paper reviews these new MR approaches to the integrated anatomic and physiologic imaging of the pulmonary vasculature.

Heart Defects, Congenital↗
PubMed1991

Differential diagnosis of hepatic neoplasms: spin echo versus gadolinium-diethylenetriaminepentaacetate-enhanced gradient echo imaging.

Early results are reported of hepatic neoplasms studied with dynamic gadolinium-diethylenetriaminepentaacetate (Gd-DTPA)-enhanced magnetic resonance imaging (MRI). The purpose of this study was to evaluate the potential of the Gd enhancement pattern for characterizing these neoplasms and to compare the performance of spin-echo (SE) to SE plus dynamic Gd-enhanced gradient-echo (GRE) pulse sequences. Forty-two patients with hepatic neoplasms were examined at 1.5 T field strength. In each patient, short and long repetition time/echo time (TR/TE) SE images were obtained, followed by pre- and post-Gd-DTPA (0.1 mmol/kg body wt), single-slice, breath-hold (13 s/scan) GRE images, which were serially acquired less than or equal to 12 min postinjection. The patterns of contrast enhancement of the various hepatic lesions were documented and analyzed. The time to peak Gd signal enhancement-to-noise ratio (SE/N), contrast-to-noise ratio (C/N), contrast (defined as the signal intensity ratio [SIR]), as well as the peak values of these quantities, were determined. The C/N and SIR values on the short and long TR/TE SE and pre-Gd GRE images for all hepatic neoplasms were also obtained. The discriminating abilities (hemangiomas vs. malignant neoplasms) of these quantities were analyzed statistically. In addition, the impact of lesion characterization on the SE versus the SE plus the Gd-enhanced GRE scans was assessed by means of a blinded reader study. Malignant hepatic neoplasms could be differentiated from hemangiomas by visual inspection of their enhancement patterns (p = 0.0009), by the time to peak C/N on Gd-enhanced images (p = 0.0002), and by the magnitude of such peak (p = 0.02). Combined SE + Gd-enhanced GRE scans afforded minor, though statistically significant (p less than 0.01), improvement of the accuracy in differentiating benign from malignant hepatic neoplasms. Late scans (12 min post-Gd) may be particularly useful in identifying hemangiomas that, unlike other neoplasms, have a significant high signal of their enhancing portions on such images.

Adult↗
PubMed1990

Magnetic resonance imaging in the evaluation of lung cancer.

MRI is used most efficaciously in the evaluation of patients with bronchogenic carcinoma when employed as a tailored examination designed to answer specific questions relevant to patient management. CT continues to be used more generally in staging lung cancer when imaging beyond conventional chest radiography is required. Specific areas in which MRI can provide important and unique information (which may supplement a CT study) include the following: (1) evaluation of the local extent of superior sulcus tumors, and (2) distinction between stage IIIA (resectable) and stage IIIB (unresectable) tumors. Confirmation of tumor invasion of major mediastinal structures is necessary before depriving a patient of potential curative resection. MRI may contribute important information when CT findings are indefinite, particularly with regard to invasion of major cardiovascular structures (eg, superior vena cava, pulmonary artery, pericardium, and heart); invasion of the tracheal carina or bilateral involvement of main bronchi; and the presence of contralateral mediastinal or hilar lymphadenopathy. MRI should be considered as a primary imaging modality to evaluate central tumors in patients for whom intravenous contrast agents are contraindicated, and as a problem-solving modality when CT is inconclusive in the detection of a possible hilar or mediastinal mass. Other specific applications of MRI include the identification of tumor recurrence in the presence of radiation fibrosis, assessment of the extent of chest wall invasion of peripheral lung tumors, and the noninvasive characterization of adrenal masses. The scope of these MRI applications in patients with lung cancer may expand in the future with refinements in motion suppression techniques, implementation of ultrafast MRI (using variations of the echoplanar method), and further development of MRI spectroscopy and MRI contrast agents.

Humans↗
PubMed1990

Multimodality imaging of a pancreatic transplant. A case report.

A 41-year-old man who had insulin-dependent diabetes mellitus from the age of 14 underwent cadaveric renal transplant in 1984. Two years later, the patient underwent pancreatic allograft transplantation. The patient did well for eight days after the operation and did not require exogenous insulin. After the eighth day, serum glucose levels rose. Multiple radiologic studies were performed to assess the possibility of graft rejection. A Tc-99m DTPA study revealed a gradual decrease in perfusion, and an In-111 oxine WBC study showed nonspecific inflammation. CT scanning and MRI displayed postsurgical anatomical relationships and excluded a peripancreatic fluid collection, but were unable to demonstrate parenchymal abnormality of the pancreas. Tests for infection proved negative. Because the decreased blood flow demonstrated by DTPA study indicated transient ischemia, the patient was treated for graft rejection and stabilized quickly.

Adult↗