I. Koh 1, J. Lee 1, J. Park 2, S. Han 2, S. Hwang 3, S. Suk 4
1 National Medical Center – Seoul,
2 Sanggye Paik Hospital, Inje University College of Medicine – Seoul,
3 Kangnam Sacred Hospital, Hallym University College of Medicine – Seoul,
4 Wonkwang University Sanbon Medical Center – Seoul, South Korea

Background: The absence of the internal carotid artery (ICA) is a rare congenital anomaly, occurring in<0.01% of the population. Although many of these cases remain asymptomatic and go undetected, their recognition is of more than trivial interest.

Case Report: Case 1: A 47-year-old woman with a history of hypertension visited the hospital with a 3-day history of headache. The results of physical and neurological examinations were unremarkable. Color-coded duplex ultrasonography performed to evaluate the carotid and vertebral arteries revealed a normal configuration on the right side. No significant stenotic flow or plaque formation was observed in the right CCA, ECA, or ICA. However, ultrasonography revealed a left CCA of diminished caliber that terminated in the ECA, with no remnant of a cervical ICA. The MR angiographic findings were consistent with the ultrasonographic findings. The left CCA terminated into the ECA with no identifiable remnant of the ICA.