摘要:

The article summarizes the basic concepts of magnetic resonance (MR) physics so that radiologists can optimize the images obtained in MR imaging of the chest. The specification of thoracic MR scan protocols is more complex than for other body regions because of cardiac and respiratory motion and blood flow. Various motion suppressing techniques such as motion compensation, respiratory compensation, and spatial presaturation have been developed, but their appropriate application is facilitated by a thorough understanding of the imaging process. Magnetic susceptibility and low proton density limit the usefulness of MR imaging in the assessment of the lung parenchyma. Nevertheless, recent studies have shown considerable improvement in image quality with the use of short echo times. Suggested imaging protocols for the evaluation of chest wall, mediastinum, hilum, heart, and great vessels are discussed.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Imaging of the lungs presents a unique challenge for MR technology. Signal from lung parenchyma is limited by low proton density, the effects of motion and susceptibility, and a multiexponential T2 relaxation time. We have illustrated the use of spin echo and projection reconstruction MR sequences in imaging lung parenchyma, and the use of a GRE sequence in imaging the pulmonary vascular tree.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Magnetic resonance (MR) imaging has both advantages and disadvantages in its application in lung cancer staging. Because of its ability to provide superior contrast resolution and to display structures in many planes, MR imaging is better than computed tomography (CT) for the detection of mediastinal and chest wall invasion. MR imaging also is more sensitive than CT for detection of hilar and mediastinal lymph node enlargement. Multiplanar T1− and T2-weighted images are optimal for differentiating lymph nodes from large vessels without the need for contrast enhancement; in these cases administration of Gd-DTPA provides no more information than plain MR images. MR studies should be used for examining patients with suspected mediastinal or chest wall invasion and those who have equivocal hilar or mediastinal adenopathy. The shortening effect of Gd-DTPA on the T1 value results in a high signal. This effect is dependent upon both the perfusion and diffusion of the contrast agent and the amount of extracellular fluid. The distribution of Gd-DTPA is similar to that of iodinated water-soluble contrast media. Gd-DTPA examination should be tailored to provide information regarding blood flow, vascularity, and permeability, none of which is easily appreciated on CT or plain MR images. Applications for which Gd-DTPA enhancement may be helpful include differentiating between malignant and benign pulmonary masses, differentiating between hilar lung cancer and peripheral postobstructive atelectasis or pneumonia, determining therapeutic effect after radiation therapy, and differentiating between recurrent or residual tumor and radiation pneumonitis.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Magnetic resonance (MR) imaging has become the method of choice for evaluating patients with brachial plexopathy. The multiplanar capability of MR imaging and its superior ability to differentiate nerves from vessels and surrounding soft tissues contribute to its success. The article describes the MR anatomy of the brachial plexus in the axial, coronal, and sagittal planes and reviews the MR characteristics of traumatic and nontraumatic etiologies of brachial plexopathy.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Magnetic resonance (MR) imaging is becoming a primary modality for evaluating the mediastinum. MR affords multiplanar imaging capabilities without exposing patients to ionizing radiation. The inherent contrast effect of different mediastinal tissues sharply delineates anatomic structures on MR images without contrast enhancement. Gradient-echo and phase-mapping techniques permit noninvasive qualitative and quantitative assessment of mediastinal blood flow. High soft tissue contrast and flow analysis capabilities make MR imaging a valuable modality for evaluating mediastinal vascular disorders. Various mediastinal tumors and their extent are best identified by the use of T1-weighted, T2-weighted, and gadolinium-enhanced images. Both primary and secondary chest wall lesions may be assessed with standard spin-echo MR images. Complex pleuroparenchymal lesions may be evaluated by means of a multiplanar approach and modified pulse sequences. This article addresses the technical parameters governing MR imaging of the mediastinum and describes MR characteristics of various pathologic conditions.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Interstitial lung disease (ILD) is a frequent manifestation of rheumatoid arthritis (RA), and it has a close bearing on the prognosis of RA patients. Computed tomography (CT) has been shown to be excellent for the diagnosis of diffuse lung disease. In this study chest radiographs and high-resolution CT (HRCT) scans were obtained in 91 patients with RA to evaluate their ILD precisely. By HRCT 43 patients could be diagnosed as having interstitial pneumonitis (IP), and 5 could be diagnosed as having bronchiolitis. The remaining 43 patients were normal by HRCT. Chest radiographic findings were consistent with the HRCT findings in approximately 50% of patients with IP. HRCT was superior to chest radiographs for the detection of early interstitial changes. The histogram of HRCT values might be a useful adjunct to HRCT diagnosis by adding some degree of objectivity. HRCT is useful for the diagnosis of ILD in patients with RA.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The article reports a review of 1140 cases of primary lung cancer diagnosed between 1974 and 1987 (13-year period) to examine the clinicopathologic features of multiple primary lung cancer. The following criteria were used: There were no malignant tumors in other organs; the tumors were separate or located in different lobes; the tumors were of different histologic types; if the histologic types were similar, there was no carcinoma in the common lymphatics of any tumors and no extrapulmonary metastases at the time of diagnosis. The following results were obtained: The incidence was 1.2% (14 of 1140 cases); 11 patients were heavy smokers; the most common histologic type was squamous cell carcinoma, and the combination of two squamous cell carcinomas was most common; 12 cases were bilateral, and 11 cases were synchronous; 19 tumors were diagnosed by bronchoscopic biopsy; 9 patients with bilateral tumors received chemotherapy and radiation therapy.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Hypersensitivity pneumonitis is an important but underdiagnosed form of interstitial lung disease. Its clinical hallmark is recurrent or chronic pulmonary symptoms of variable severity associated with an array of systemic symptoms but without extrapulmonary structural abnormalities. Clinical suspicion is the key to diagnosis, which is supported by establishing an environmental or occupational exposure to a causative inhaled antigen; by excluding infectious and other causes of recurrent, migratory, or progressive radiologic lung abnormalities; and by demonstrating antigen-specific antibodies in the serum. Two cases of hypersensitivity pneumonitis are described that illustrate the widely variable clinical, laboratory, and radiologic presentations and emphasize the importance of diagnosing this treatable condition.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Hydatid cysts of the heart are rare and account for 0.5% to 2.0% of all hydatid infestations. The article describes a well-documented intracardiac hydatid cyst in a child. Because these cysts enlarge slowly, they rarely present in early childhood.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The article describes eight patients with enlarged internal mammary lymph nodes visualized on the frontal plain chest radiograph. Enlarged internal mammary lymph nodes cast shadows that initially may be mistaken for a mediastinal or pleural abnormality. Although the lateral film alone may suggest these nodes, the findings on the frontal film help lateralize the abnormality.

ISSN:0883-5993    

出版商:OVID    

年代:1993

数据来源: OVID