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Biomedical subjects

P Batra

Publications and source records attributed to P Batra.

At least 19 recordsLinked to original sources
PubMed1999

Computed radiography dual energy subtraction: performance evaluation when detecting low-contrast lung nodules in an anthropomorphic phantom.

A dedicated chest computed radiography (CR) system has an option of energy subtraction (ES) acquisition. Two imaging plates, rather than one, are separated by a copper filter to give a high-energy and low-energy image. This study compares the diagnostic accuracy of conventional computed radiography to that of ES obtained with two radiographic techniques. One soft tissue only image was obtained at the conventional CR technique (s = 254) and the second was obtained at twice the radiation exposure (s = 131) to reduce noise. An anthropomorphic phantom with superimposed low-contrast lung nodules was imaged 53 times for each radiographic technique. Fifteen images had no nodules; 38 images had a total of 90 nodules placed on the phantom. Three chest radiologists read the three sets of images in a receiver operating characteristic (ROC) study. Significant differences in Az were only found between (1) the higher exposure energy subtracted images and the conventional dose energy subtracted images (P = .095, 90% confidence), and (2) the conventional CR and the energy subtracted image obtained at the same technique (P = .024, 98% confidence). As a result of this study, energy subtracted images cannot be substituted for conventional CR images when detecting low-contrast nodules, even when twice the exposure is used to obtain them.

Analysis of Variance↗
PubMed1997

Chest teleradiology in a teaching hospital emergency practice.

OBJECTIVE: New standards for hospital accreditation and health care reimbursement may require that faculty subspecialists be more available after regular working hours to supervise residents in academic radiology departments. We designed a receiver operating characteristic study to determine whether a thoracic radiologist who evaluated computed radiography (CR) images of the chest at a home-based teleradiology workstation could add significant value to a junior resident's interpretations of films within the hospital for acutely ill patients. SUBJECTS AND METHODS: Using a hybrid cassette, we obtained analog chest films and CR images simultaneously for each of 252 acutely ill patients in the emergency department and in an intensive care unit. Interpretations of the analog films by three first-year residents were analyzed for 11 parameters deemed critical for patient management. Likewise, CR images of the same chest studies were viewed on a home teleradiology workstation by a faculty thoracic radiologist who analyzed the images for these 11 interpretive parameters. All interpretations by radiology residents and by the home-based thoracic radiologist were then compared with the interpretations of a consensus panel consisting of another thoracic radiologist and a full-time emergency department radiologist. RESULTS: Analysis of the pooled results from the three junior residents as a group failed to show significant differences between their interpretations of chest films and the interpretations of CR images by a thoracic radiologist at a home workstation. However, we observed significant differences for several image interpretation parameters between individual residents and the home-based radiology subspecialist. CONCLUSION: The data confirm that significant value can be added to the interpretations of chest films by individual junior residents when a home-based thoracic radiologist uses teleradiology to provide expert interpretations. Accordingly, it is reasonable to infer that on-line supervision by faculty subspecialists via teleradiology could be used to complement the scheduled visits that are being made now by individual faculty members of our institution to interpret films periodically with a radiology resident during overnight and weekend periods.

Emergency Service, Hospital↗
PubMed1996

Rounded atelectasis.

Rounded atelectasis (RA) is a special type of peripheral lung collapse that develops as a result of pleural disease. Most cases have been attributed to asbestos inhalation, but many other causes have also been implicated. It is usually detected incidentally in an asymptomatic older man. RA can be diagnosed by a constellation of radiologic findings. It appears as a rounded masslike opacity in the peripheral lung adjacent to thickened pleura and with curvilinear opacities of bronchi and vessels (comet tail) extending from the site of RA toward the hilum. Volume loss of the affected lobe is uniformly present. In addition to the classic lesion, a spectrum of atypical lesions has also been described. Computed tomography (CT) and high-resolution CT demonstrate the full extent of disease better than chest radiography. Familiarity with this benign condition is important to differentiate it from other pulmonary and pleural diseases and to prevent unnecessary invasive procedures and surgical resection.

Diagnosis, Differential↗
PubMed1995

Comparison of hard- and soft-copy digital chest images with different matrix sizes for managing coronary care unit patients.

OBJECTIVE: This study was to determine whether different digital display formats for portable chest radiographs of coronary care unit patients would provide comparable information for clinical care. In particular, we tried to ascertain whether 1024 x 1024 pixel (1K) images on a picture archiving and communication system (PACS) workstation would be comparable to 1760 x 2140 pixel (2K) images on workstations or to digital films. If comparability could be proved, we hypothesized that 1K workstations could considerably lower equipment and film costs and facilitate image transmission from point to point. MATERIALS AND METHODS: Four chest radiologists read a panel of chest studies assembled from 98 coronary care unit patients, comparing 1K and 2K soft-copy images with digital hard copies. For all three image types for the 98 patients, the readers evaluated nine image parameters that the cardiologists deemed essential for clinical decision making. Two other chest radiologists reviewed each patient's three image types, historical chest images, current and prior radiologic reports, and medical record to determine the consensus, or "truth findings." RESULTS: With one exception (small pleural effusions), the receiver operating characteristic analysis showed no significant differences in the clinical information derived from the three image types. CONCLUSION: For clinical management in a coronary care unit, comparable information can be obtained from digital radiologic chest studies using a 1K x 1K soft-copy format, a 2K x 2K soft-copy format, or a hard copy (film). Substantial savings in cost and time are therefore possible by using soft-copy images and lower resolution (1K x 1K) workstations and, when necessary, by transmitting images on regular telephone lines.

Coronary Care Units↗
PubMed1995

Pulmonary thromboembolism: spectrum of findings on CT.

CT has emerged as a potentially important diagnostic technique in pulmonary thromboembolism that can provide direct visualization of the obstructing embolus and its associated vascular and pleuroparenchymal sequelae. Although the role of contrast-enhanced CT in the diagnostic algorithm of pulmonary embolism has not been defined, patients at risk for pulmonary embolism frequently undergo thoracic CT as part of the assessment for other cardiopulmonary conditions. As such, CT may provide the first indication of clinically significant pulmonary embolic disease. This essay reviews the vascular, pleural, and parenchymal features of pulmonary thromboembolism observed on CT scans, describes the limitations of CT, and discusses the imaging features of pulmonary embolism that overlap other clinical conditions.

Adult↗
PubMed1995

High-resolution computed tomography, magnetic resonance imaging, and positron emission tomography in interstitial lung disease.

In patients who have interstitial lung disease, chest radiography remains the primary imaging technique for both initial diagnosis and follow-up. For further investigation of selected patients the imaging modality of choice is currently high-resolution computed tomography. Magnetic resonance imaging and positron emission tomography have great potential in this field, particularly with respect to disease activity, but are still largely experimental and are not routinely employed.

Humans↗
PubMed1994

Intrathoracic calcifications: radiographic features and differential diagnoses.

Intrathoracic calcifications occur in a wide variety of disorders. Although they are usually harmless sequelae of remote processes, calcifications provide important information for establishing the diagnosis or for evaluating the progression of known disease. They may arise in the pulmonary parenchyma, mediastinum, hilar and mediastinal lymph nodes, pleura, chest wall, or any combination of these structures. The cause of the calcification may be determined by means of the location and pattern of the calcifications within the lung parenchyma and knowledge of the associated clinical features. Calcifications in the thorax are frequently manifestations of previous infectious processes. Less often, they may be due to neoplasms, metabolic disorders, occupational exposure, or previous medical therapy. Large intrathoracid calcifications are usually identified on conventional chest radiographs; detection of smaller calcifications may require use of other imaging modalities, such as dual-energy digital radiography, fluoroscopy, radionuclide scanning, computed tomography (CT), and high-resolution CT.

Calcinosis↗
PubMed1993

The effect of irreversible image compression on diagnostic accuracy in thoracic imaging.

RATIONALE AND OBJECTIVES: Digital image compression reduces the storage requirements and network traffic on picture archiving and communications systems. Full-frame bit-allocation (FFBA) is an irreversible image-compression method based on the discrete cosine transform that provides for high compression ratios with a high degree of image fidelity. METHODS: One hundred twenty-two posteroanterior chest radiographs were obtained on patients in an ambulatory patient setting, including 30 cases of interstitial lung disease, 45 images containing combinations of lung nodules (N = 37) or mediastinal masses (N = 39), and 47 normal images containing none of the pathology for which we were testing. The images were digitized (nominal 2 K x 2 K x 12-bit resolution), printed on a 35 x 35-cm hard copy format, and compressed at an approximate compression ratio of 20:1. Observer performance tests were conducted with five radiologists using receiver operating characteristics analysis on digitized uncompressed and compressed hard copy images. RESULTS: There were no significant differences between the two display conditions for the detectability of any of the thoracic abnormalities. CONCLUSIONS: Our preliminary results suggest that irreversible image compression at ratios of 20:1 may be acceptable for use in digital thoracic imaging.

Algorithms↗
PubMed1992

Pulmonary coccidioidomycosis.

Coccidioidomycosis is a fungal disease endemic in the southwestern desert area of the United States. The infection is acquired by inhalation of arthrospores, and 60% of the infections are asymptomatic. Chest radiographic abnormalities are common and may even be seen in asymptomatic cases. In patients with acute infection, segmental or lobar consolidation and nodular or patchy pulmonary opacities are frequent. Hilar and mediastinal adenopathy may be present in 20% of cases, usually with parenchymal findings. A small pleural effusion may occur in 20% of cases. Approximately 5% of patients with primary disease are left with chronic, residual lesions of the lung. These consist of nodules, cavities, pneumonia, adenopathy, pleural effusion, fibrosis, bronchiectasis, and calcification. Rarely, in about 0.5% of cases, the infection may disseminate to any organ. The chest radiograph demonstrates a miliary or reticulonodular pattern and mediastinal adenopathy. Overall the disease is benign in nature; but patients with severe, progressive pulmonary or disseminated disease often require medical and occasionally surgical management.

Coccidioidomycosis↗
PubMed1992

Imaging techniques in the evaluation of pulmonary parenchymal neoplasms.

Conventional PA and lateral chest radiographs continue to be the initial examination of choice to evaluate patients who are suspected of having a pulmonary parenchymal neoplasm. A lung lesion can be characterized as probably benign or malignant based on its radiographic appearance (size, shape, margins, presence of calcification, cavitation or air bronchograms, growth rate). A spiculated or lobulated lesion greater than 3 cm in size that is noncalcified is highly suspicious for malignancy. A lung lesion less than 3 cm in size with smooth borders that appears noncalcified on conventional radiographs should be examined by CT, including densitometry to detect calcification or fat, which indicates benignity. In patients with known lung cancer, CT can help to stage the tumor by indicating hilar or mediastinal involvement, or distant metastases. Currently, MR imaging has a limited role, but can be used as a "problem solving" modality for selected cases in evaluating pulmonary parenchymal neoplasms.

Diagnosis, Differential↗
PubMed1991

Effect of aflatoxin B1 on the efficacy of turkey herpesvirus vaccine against Marek's disease.

The effect of feeding aflatoxin B1 (AFB1) (0.5 ppm) was studied in young chicks. The frequency and the severity of gross and microscopic lesions of Marek's disease were significantly higher in those birds which had been vaccinated with turkey herpesvirus (HVI) and birds challenged with Marek's disease virus which had been given AFB1 in the feed than in those given normal feed. The protective efficacy of HVT vaccine, as judged on the basis of gross and histopathological lesions, was 86.1 and 77.3 per cent in normally fed birds in comparison to 37.6 and 8 per cent in AFB1 fed birds.

Aflatoxin B1↗
PubMed1991

Mediastinal masses: magnetic resonance imaging in comparison with computed tomography.

Seventy-eight patients with mediastinal abnormalities were imaged with magnetic resonance imaging (MRI) to evaluate mediastinal masses and associated lung, pleural, or chest wall disease. Magnetic resonance images were compared with computed tomography (CT) scans, which were available in 45 patients. While MRI and CT were equally effective in demonstrating mediastinal lesions, CT was superior for displaying calcification within a mass in eight patients and for demonstrating associated lung abnormality in four patients. Computed tomography should remain the imaging procedure of choice after chest radiography to evaluate mediastinal masses, although MRI may be indicated in selected patients.

Adolescent↗
PubMed1991

Pulmonary dysfunction in advanced liver disease: frequent occurrence of an abnormal diffusing capacity.

PURPOSE: Abnormalities in pulmonary function have been reported in association with chronic liver disease of varied etiology. The aim of this study was to better define the frequency and nature of these abnormalities in patients who were being evaluated for liver transplantation. PATIENTS AND METHODS: We performed a battery of pulmonary function tests and chest radiographs in 116 consecutive patients (50 men, 66 women; aged 19 to 70 years, mean 44.6 years) with severe advanced liver disease who were hospitalized specifically for evaluation for possible orthotopic liver transplantation and were able to perform technically satisfactory tests. In 17 patients, quantitative whole-body technetium-99m macroaggregated albumin perfusion scanning was also performed for assessment of possible right-to-left shunting through intrapulmonary vascular dilatations. RESULTS: The most commonly affected test of lung function was the single-breath diffusing capacity for carbon monoxide (DLCO), which was abnormal in 48%, 45%, and 71% of patients who never smoked, former smokers, and current smokers, respectively. Ventilatory restriction was noted in 25% of all patients, airflow obstruction (reduced ratio of forced expiratory volume in 1 second to forced vital expiratory volume in 1 second to forced vital capacity) in only 3%, and a widened alveolar-arterial oxygen gradient in 45%. Diffusion impairment was accompanied by a restrictive defect in only 35% of the patients and by an abnormally widened alveolar-arterial oxygen gradient in 60%. When diffusion impairment was accompanied by an oxygenation defect, it was also associated with a significantly increased right-to-left shunt fraction (mean 24.9%) assessed from quantitative whole-body perfusion imaging. On the other hand, isolated diffusion impairment unaccompanied by significant hypoxemia (noted in approximately a third of the patients with a reduced DLCO) was not associated with evidence of significant intrapulmonary shunting (mean right-to-left shunt fraction 6.7%). CONCLUSIONS: Most patients with advanced liver disease have one or more types of abnormality in lung function, a reduced DLCO being the single most common functional defect. Mechanisms accounting for the abnormality in gas transfer may include intrapulmonary vascular dilatations, diffuse interstitial lung disease, pulmonary vaso-occlusive disease, and/or ventilation-perfusion imbalance.

Adult↗
PubMed1991

Magnetic resonance imaging of chest wall lesions.

Magnetic resonance imaging (MRI) demonstrates surface anatomy, nerves, and soft tissue pathology. Selective placement of the cursor lines in MRI displays specific anatomy. The MR images can then be used as adjunct in teaching surface anatomy to medical students and to other health professionals. Because the normal surface anatomy could be imaged at UCLA's radiology department, it was decided to image soft tissue abnormalities with MR to assist in patient care. Patients imaged were scheduled for special procedures of the chest or staging lymphangiograms. Patients were placed into categories depending on known diagnosis or interesting clinical presentation. The diagnostic categories included Hodgkin's disease, melanoma, carcinomas (eg, lung or breast), lymphedema, sarcomas, dermatological disorders, and neurological disorders. All images were orchestrated by the radiologist. This article discusses both the teaching and clinical impact on patient care.

Adult↗
PubMed1991

AIDS: immunologic abnormalities following human immunodeficiency virus infection.

Following human immunodeficiency virus (HIV) infection, there is an ordered progression of immunologic abnormalities that results from the selective infection of the T4 helper/inducer subset of T lymphocytes. The loss of helper T-cell function disrupts both the cellular and humoral aspects of the immune response. The T lymphocytes decrease in both number and function. The peripheral blood B lymphocytes demonstrate marked polyclonal activation and are unable to mount a serologic response to new antigens. The infected monocytes and macrophages serve as reservoirs for HIV and act as vehicles that transport the virus to target organs. Decreased activity of natural killer cells may promote progression of acquired immunodeficiency syndrome (AIDS). Factors that suppress the reaction of T and B lymphocytes to stimuli have been identified in the sera of AIDS patients. In conclusion, HIV infection causes progressive dysfunction and destruction of the entire immune system, resulting in severe opportunistic infections, neoplasms, and shortened survival of AIDS patients.

Acquired Immunodeficiency Syndrome↗