Substantia Nigra Scans (1 of 2) (image) Radiological Society of North America Caption Top row: 7-T three-dimensional multiecho susceptibility-weighted in vivo images of SN in healthy 64-year-old man, located between the crus cerebri (a) and the red nucleus. Axial sections perpendicular to the floor of fourth ventricle are obtained at level of the inferior third of the red nucleus (level I), at the level of decussation of superior cerebellar peduncles (e) (level II), and at the level of the inferior colliculi (level III). At level I, SN appears as homogeneous hypointense structure in the medial part of the cerebral peduncle, and is laterally constituted by a hyperintense oval area between two hypointense layers (c1). At level II, a trilaminar organization of the SN with a central hyperintense layer (b) between two hypointense tiers (c and d) is detectable. At level III, the dorsal hypointense lamina could be detected as a small residual lateral hypointense area, while the hyperintense layer fades into the isointense cerebral peduncle. Bottom row: 7-T three-dimensional multiecho susceptibility-weighted in vivo images of the SN in PD patients. The loss of normal anatomy of the SN in a 61-year-old man with PD is characterized by the disappearance of the oval-shape bright spot in the lateral part of the SN at level I and by the loss of the hyperintense intermediate layer of the SN at level II. HC = healthy subject. Credit Radiological Society of North America Usage Restrictions May use with credit Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.