Agenesis of the internal carotid artery: color Doppler, CT, and MR angiography findings.

Agenesis of the internal carotid artery (ICA) is a rare finding that can lead to the false diagnosis of an ICA occlusion. We present the case of a young woman with agenesis of the left ICA. Diagnosis was made noninvasively by color Doppler imaging (CDI) in combination with high-resolution CT of the base of the skull. Magnetic resonance angiography confirmed the diagnosis. CDI in combination with CT of the base of the skull allows the diagnosis of ICA agenesis without the use of invasive procedures.