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Potential pitfalls in the interpretation of diseases involving the mediastinum are seen when imaging with computed tomography and [18F]-fluoro-2-deoxy-d-glucose positron emission tomography. These pitfalls can involve any mediastinal structure, including the mediastinal vessels, heart, lymph nodes, thymus, trachea, esophagus, and fat. Misinterpretation of normal variants or benign conditions as pathology can affect staging and alter treatment. After reading this review, the reader should be able to identify common mediastinal imaging pitfalls and apply ancillary measures to confirm the correct diagnosis and thus reach an accurate diagnosis to facilitate correct patient treatment.

Purpose: Comparison of multidetector-row CT (MDR-CT) of the chest with and without ECG triggering for the detection of pulmonary metastases. Materials and Methods: Fifty patients with malignant tumors underwent CT of the chest. The unenhanced phase was performed with ECG-triggered MDR-CT and the contrast-enhanced phase with helical MDR-CT. The ECG-triggered and standard helical scans were interpreted in separate sessions, with the analysis determining the number and demarcation of the intrapulmonary nodules and the delineation of the mediastinal structure (rated 1 = excellent to 5 = poor). Results: ECG-MDR-CT images detected 38% more pulmonary nodules than MDR-CT. The detection rate for tumors < 5 mm was 64% higher in ECG-triggered scans. The median demarcation rating of all pulmonary findings was 2 for ECG-MDR-CT and 3 for MDR-CT. The median demarcation rating of tumors < 5 mm was 3 for ECG-MDR-CT and 4 for MDR-CT. Mediastinal structures were better delineated by ECG-triggering. The median demarcation rating of the vessels and left bronchus was 2 for ECG-MDR-CT and 4 for MDR-CT. Detection rate and demarcation rating of pulmonary tumors and the delineation of mediastinal structures were not significant different for either CT technique. Conclusion: Our study indicates superiority for ECG-MDR-CT.

Enlargement of mediastinal structures can cause compression of the trachea and/or bronchi. We describe two case reports in which stenosis of left main bronchus, secondary to compression from an enlarged mediastinal structure, were successfully managed with temporary placement of a metallic self-expanding stent while waiting for the compression to relieve.

1109 he pericardium, consisting of a fibroserous sac that encloses the heart, is routinely imaged on CT [1–4]. Multidetector technology, in allowing rapid acquisition of volumetric data in high resolution and multiplanar reformation, has improved anatomic imaging. Imaging with narrow collimation results in improved delineation of cardiovascular anatomy and routine visualization of the pericardial recesses. The pericardial space normally contains a small amount of fluid (15–20 mL), and the fluidfilled recesses and sinuses can be misinterpreted as adenopathy or abnormality of an adjacent mediastinal structure. In oncologic imaging, staging and prognostic implications of fluid in a pericardial recess misinterpreted as adenopathy can significantly alter management and therapy. We review the anatomy of the pericardium with emphasis on the pericardial recesses that can potentially be misinterpreted as adenopathy.

Mediastinal interfaces on a chest radiograph result from contact between mediastinal structures and the adjacent lung, while mediastinal lines result from contact between the two lungs across the midline. A variation of mediastinal interface is mediastinal stripe, a narrow band produced by contact of both sides of a mediastinal structure with the lungs. Alterations in mediastinal interfaces and lines may be due to variations in normal anatomy, or may reflect the presence of a abnormalities within the mediastinum. Familiarity with the various normal mediastinal interfaces and lines, and the changes that occur with disease is important for the interpretation of the chest radiograph and in the diagnosis of mediastinal abnormalities. The purpose of this pictorial essay is to illustrate the most imortant normal and abnormal interfaces and lines and also to correlate radiography and CT findings.

Necrotizing aortitis with rupture is a rare complication of radiation of mediastinal structure. To our knowledge, this is the first electron microscopic study of radiation changes of the aorta. Collagen fibers were preserved, but there was slit-like irregular fragmentation of elastic fibers. Marcias-Rojas and Castro1previously reported five cases of postradiation rupture of the aorta, all associated with mediastinitis. Our patient had an empyema. It is postulated that infection combined with radiation necrosis may have triggered the rupture.

Three patients with lung cancer have been cured by incomplete removal of the cancer, which has for 20 years been the policy of this unit when complete removal is not possible. In each patient residual cancer remained on the wall of the left atrial chamber of the heart at the end of an operation for pneumonectomy. Incomplete removal of cancer may, as a rare event, cure the patient. When residual cancer remained on any mediastinal structure other than the atrium cure has not been seen, though progress of the cancer seems to be retarted in some patients.