B-MODE IMAGING OF INTRALUMINAL THROMBUS OF THE INTERNAL CAROTID-ARTERY - EXAMPLES OF A DIAGNOSTIC CHALLENGE

Six patients with the diagnosis of intraluminal thrombus of the internal carotid artery are reported. In the first 2 patients with large thrombi, CW-Doppler sonography, B-mode scanning, and histological findings were in agreement. The third patient had CW-Doppler and B-mode sonographical findings of a large intraluminal thrombus immediately before an embolic cerebral infarct. Three weeks later, angiography showed a plaque with only an excavation remaining. Another patient had an intraluminal thrombus superimposed on a nonstenosing plaque which was not detected by CW-Doppler sonography but could be identified during B-mode scanning. Angiography and pathoanatomy were confirmative. The fifth patient with B-mode visualization of an echolucent intraluminal structure did not show any thrombus intraoperatively. The sixth patient is reported to demonstrate the failure of B-mode imaging as well as angiography in detecting clots which were found pathoanatomically. Intraluminal thrombi as potential sources of brain embolism can be attached to atherosclerotic plaques of any degree of stenosis. Nonstenosing lesions with an attached thrombus may escape CW-Doppler sonography and even angiography but may be shown during high-resolution B-mode imaging. False-positive findings, however, cannot be avoided. Plaques with thrombi may cause strokes more frequently than assumed.