A 36 year-old male with a history of dizziness and suspected cerebrovascular pathology was referred to our center for angiographic evaluation of carotid and vertebral arteries. He underwent multidetector 64-row computed tomography (MDCT) angiography. (GE: Optima660,2011, Tokyo, Japan60). Eighty-five milliliter of nonionic iohexolcontrast (Omnipaque, 350 mg I/ml, GE Healthcare, Shanghai, China) was injected at a rate of 5 ml/s by a power injector through the antecubital vein. The acquired images (slice thickness 0.625 mm) were further analyzed in a work station (GE: AW Volume Share 4) to generate volume-rendered (VR) and maximum intensity projection (MIP) images.\nThe left vertebral artery (LVA) had two separate limbs of origin []. The medial limb (2.2 mm in diameter at its origin) originated directly from the aortic arch in between the origins of left common carotid (LCCA) and left subclavian arteries (LSA) []. The lateral limb (2.4 mm in diameter at its origin) emanated from the LSA in its orthodox position and entered the foramen transversarium of C6 vertebra. Both the limbs united to form a single trunk at C5-C6 interval and the single trunk (3.2 mm in diameter) then entered C5 transverse foramen [Figures and ]. Both the limbs of the right vertebral artery (RVA) originated from the right subclavian artery (RSA) []. The medial limb (3.9 mm in diameter at its origin) originated from its orthodox position, whereas the lateral limb (2.4 mm in diameter at its origin) arose more posteriorly close to the origin of thyrocervical trunk. The lateral limb entered the C6 transverse foramen, but the medial limb entered the carotid space lying posteromedial to right common carotid artery (CCA) []. At the interval between the C4 and C5 vertebrae, both the limbs fused to form a single trunk (4.4 mm in diameter) which entered the C4 transverse foramen [Figures and ]. Further distal course of both vertebral arteries was normal and no cerebrovascular pathology could be detected.
A 38-year-old woman was referred to our department because of dizziness. CT angiography demonstrated an incidental right duplicated VA originating from the right subclavian artery. Axial CT showed that the medial limb of the duplicated VA was located posteromedially to the right CCA and anteriorly to the vertebral transverse foramen. Sagittal CT revealed that the medial limb of the duplicated VA was located in close proximity to the CCA and internal carotid artery (). The patient was managed conservatively, and her dizziness improved.