Dissection of internal carotid artery: Diagnosis with color doppler sonography and MR angiography correlation

We present findings of extracranial color Doppler sonography in patients with internal carotid artery dissection consistent with those of magnetic resonance (MR) angiography. In color Doppler sonography, the direct diagnostic signs likely to be present are linear hyperechoic intimal flap crossing the vessel lumen, eccentric hypoechoic thrombus formation, bi- directional flow in the true and false lumen, respectively and damped systolic spectral waveform with reverse diastolic flow. Indirect signs indicating internal carotid artery dissection are biphasic Doppler waveform and regional turbulent flow. In addition, the absence of atherosclerotic wall change is an important finding suggestive of nonatherosclerotic stenosis or occlusion. These findings indicate that color Doppler sonography combined with MR angiography may be an alternative diagnostic tool to the conventional angiography in the confirmation diagnosis of the dissection of internal carotid artery. Color Doppler sonography still can not entirely replace the angiographic study; Color Doppler sonography helps to indicate angiography and serves as an alternative during follow-up studies. Sequent examinations prove helpful in determining the duration of anticoagulant treatment.