Pearls and Pitfalls presented by Dr. David Yousem elucidate neuroradiology topics. In this study we find abnormal signal intensity, which is present, both in the anterior portions of the brain bilaterally and symmetrically, as well as, in the posterior portions of the brain. The pons is involved as well as the cerebellum. The post-contrast T1 weighted scans demonstrate little enhancement. Dr. Yousem will review the T2 weighted series and the diffusion images with you and discuss the differential diagnosis.