The General Appearance of Edema and Hemorrhage on CT, MR and US (Including a General Introduction to CT, MR and US Scanning)

J.L. Creasy, Dating Neurological Injury: A Forensic Guide for Radiologists, Other Expert Medical Witnesses, and Attorneys, DOI 10.1007/978-1-60761-250-6_2, © Springer Science+Business Media, LLC 2011 Abstract This chapter begins with a discussion of the terminology and hardware of computed tomographic (CT), magnetic resonance (MR), and ultrasound (US) imaging. This includes an introduction to CT numbers and very basic MR image formation, sequence types, and sequence usages. The remainder of the chapter is an introduction to edema and hemorrhage. The two basic types of edema are cytotoxic and vasogenic. The appearance of these types of edema is presented on CT, MR, and US. The general imaging of hemorrhage – without following in detail the evolution of these findings with time – and the various spaces in which it occurs in the brain are discussed and demonstrated on CT, MR, and ultrasound.