Image of the Month

A 56-year-old woman developed headache and dysphagia immediately after shoulder surgery under general anesthesia. History included vertebrobasilar migraine on the left side of her face for the last 15 years and the postoperative headache was presumed to be migraine. When symptoms persisted despite migraine treatment, she was referred to neurology. To find out how imaging led to the correct diagnosis, see Image of the Month, p. 11.