Normal Anatomical Features and Variations of the Vertebrobasilar Circulation and Its Branches: An Analysis with 64-Detector Row CT and 3T MR Angiographies

Veysel Akgun,Hakan Akgun,Yalcin Bozkurt,Oguzhan Oz,Sebahattin Sari,Salih Hamcan,Bilal Battal

doi:10.1155/2013/620162

Abstract

Purpose. To determine the normal anatomical features and variations of the vertebrobasilar circulation and its branches in patients who underwent multidetector computed tomography (CT) or magnetic resonance (MR) angiographies of the brain. Methods. 135 patients (male, 83 and female, 52; mean age, 50.1 years) who underwent CT (n = 71) or MR (n = 64) angiographies of the vertebrobasilar vasculature for various reasons were analyzed retrospectively. The right and left distal vertebral arteries (VAs), posterior inferior cerebellar arteries (PICAs), anterior inferior cerebellar arteries (AICAs), superior cerebellar arteries (SCAs), posterior cerebral arteries (PCAs), and posterior communicating arteries (PCoAs) were analyzed individually. Results. In 24.4% of the cases (33/135) right PICA, in 19.3% of the cases (26/135) left PICA, in 17.8% of the cases (24/135) right AICA, and in 18.5% of the cases (25/135) left AICA were absent. In cases without PICA or AICA, there was a statistically significant, moderately or well-developed AICA or PICA on the same side, respectively (P < 0.001). The most common variation was isolated absence of right PICA and was seen in 17.8% of the cases. Conclusions. The anatomic features of the branches of the vertebrobasilar circulation may be different from well-known normal anatomy. CT and MR angiographies allow a precise and detailed evaluation of vertebrobasilar circulation.

Highlights

The vertebrobasilar system that is known as a posterior circulation is an important vascular network that supplies blood to the posterior part of the cerebral hemispheres including the occipital lobes and the posterior portions of the temporal lobes, the cerebellum, and the brainstem
The basilar artery divides into the 2 posterior cerebral arteries (PCAs) at the level of the proximal midbrain, just after passing the oculomotor nerves
In 4 cases right vertebral arteries (VAs) and in 2 cases left VAs were becoming prominently thinner after giving the posterior inferior cerebellar arteries (PICAs) branches (

Summary

Introduction

The vertebrobasilar system that is known as a posterior circulation is an important vascular network that supplies blood to the posterior part of the cerebral hemispheres including the occipital lobes and the posterior portions of the temporal lobes, the cerebellum, and the brainstem. This system supplies approximately 20% of the intracranial blood flow [1,2,3]. The basilar artery supplies portions of the cerebellum through the anterior inferior cerebellar arteries (AICAs) arising at the junction of its proximal and middle thirds, as well as the superior cerebellar arteries (SCAs) originating just prior to its termination (Figure 1). The anatomical features and variations of the vertebrobasilar system must be well known for accuracy of the interpretation of the ischemic areas, diagnoses, endovascular interventions, and posterior cranial fossa surgeries

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