Angiographic differentiation of thoracic aneurysms and neoplasms.

The distinction between nondissecting aneuryms of the thoracic aorta and thoracic neoplasms may be difficult. The aortographic findings associated with aneurysms may be subtle. However, when the aortogram is properly performed and interpreted and the findings correlated with the plain chest roentgenograms the distinction between aneurysms and neoplasms may be made consistently. The thoracic aortogram should be filmed in at least 2 projections and abdominal aortography and ultrasonography should be performed. With aneurysms the aortographic signs include widening (often slight) of the aortic lumen, thickening of the aortic wall, small ulcer-like collections of contrast and non-filling of regional intercostal arteries. With neoplasms none of these radiological features is to be anticipated, while the aorta will be normal, displaced or narrowed.