Magnetic resonance angiographic diagnosis of ectatic vertebral artery

In the cervical spine, routine and contrast magnetic resonance (MR)- and computed tomography (CT)-based studies may fail to differentiate between an ectatic vertebral artery and a solid foraminal mass. A complete cervical and lumbar Myelo-CT scan in a 67-year-old female with lumbar stenosis revealed an incidental, left-sided C3-C4 foraminal mass. A vascular lesion was suspected when the MR study revealed the lesion to be a signal void. MR angiography confirmed an ectatic C3-C4 vertebral artery loop. The possibility of a vertebral artery anomaly should be considered in patients with asymptomatic lateral and foraminal cervical lesions on CT studies. In these patients, routine MR and MR angiography are necessary to demonstrate the status of the vertebral artery in the foramen.