Murray Rebner

CT evaluation of enhancing mediastinal masses.

The CT scans of 132 patients with mediastinal masses and CT scans from our teaching file were retrospectively reviewed to evaluate the role of contrast enhancement in limiting the differential diagnosis of a mediastinal mass. Ten patients with an enhancing mediastinal mass were found. Coupled with mass enhancement, location and hypertension were helpful in limiting the differential diagnosis. Four masses were of thyroid origin, and all were contiguous with neck thyroid. All patients with functioning paragangliomas were hypertensive and all intrapericardial enhancing masses were functioning paragangliomas. A normotensive patient had a nonfunctioning aortic body paraganglioma superiolateral to the aortic arch. An enhancing mass in a similar location in a hypertensive patient was a functioning paraganglioma. Castleman disease occurred posterior to the heart.

CT evaluation of mediastinal masses

CT is an important modality for imaging mediastinal masses, and certain CT attenuation features (fat, calcium, or water attenuation, contrast enhancement) are well known to suggest specific diagnoses. In a series of 132 consecutive patients with tissue-proven mediastinal masses, these specific CT features were present in only 16. We evaluated the ability of CT to differentiate soft tissue mediastinal masses based on morphology and distribution of disease. Metastatic disease and lymphoma accounted for 69% of masses in this series, and CT could not generally differentiate them. However, CT was helpful in differential diagnosis in certain settings. CT demonstration of multiple mediastinal masses when conventional radiographs showed a single mass generally excluded diagnoses such as thymoma and teratoma. CT demonstration of a single middle mediastinal mass, frequently missed by conventional radiography, made metastatic disease a much more likely diagnosis than lymphoma. Finally, CT demonstration of certain ancillary findings strongly favored a diagnosis of lymphoma (axillary adenopathy) or metastatic disease (solitary pulmonary mass, focal liver lesions, bone lesions).

CT appearance of right gonadal vein.

The CT appearance of the right gonadal vein was studied. It is usually first seen 1 cm below the bifurcation of the inferior vena cava (IVC) and empties into the IVC laterally or anterolaterally 4 cm below the union of the right renal vein and IVC. Occasionally, it empties into an accessory right renal vein rather than the IVC. The right gonadal vein was visualized partially or completely in 80% of patients, and generally measured ≤4 mm in maximum diameter. It was enlarged in a patient with portal hypertension and in a postpartum woman. Knowledge of its typical CT appearance should prevent confusion with abdominopelvic lymph nodes.