TY - CHAP M1 - Book, Section TI - Magnetic Resonance Imaging in Obstetrics A1 - Bailey, April A. A1 - Twickler, Diane M. A2 - Fleischer, Arthur C. A2 - Abramowicz, Jacques S. A2 - Gonçalves, Luis F. A2 - Manning, Frank A. A2 - Monteagudo, Ana A2 - Timor, Ilan E. A2 - Toy, Eugene C. PY - 2017 T2 - Fleischer's Sonography in Obstetrics and Gynecology: Textbook and Teaching Cases, 8e AB - Key TermsDiffusion-weighted imaging (DWI): an MR sequence that has increased signal when Brownian motion of water molecules is restricted, such as highly cellular tumors, fibrosis, hypoxic edema of the brain, and abscess with viscous content.Fat suppression: various techniques used to make fat dark (low signal intensity) on MR images in order to highlight other tissues and, depending on the technique used, confirm the presence of fat within a structure.Magnetic resonance (MR) imaging: a modality that uses high-field-strength magnets, radio frequencies, and a computerized analysis to produce detailed in vivo images of internal anatomy of the body.Orthogonal views: MR views at right angles to each other, typically axial, coronal, and sagittal views of the fetus.Signal-to-noise ratio (SNR): the amount of desired signal or useful information divided by the background level of false data or noise. High SNR results in a clear image.Steady-state MR imaging: an MR technique that is rapid with excellent SNR and relatively motion insensitive based on a fast gradient echo sequence.T1-weighted imaging: MR technique that is less sensitive for fetal anatomy but highlights characteristics of fat, certain stages of bleeding, liver parenchyma, and meconium in the colon at later gestations based on sequences using a short repetition time and short echo time. Simple fluid is dark (low signal intensity) on a T1-weighted image.T2-weighted imaging: MR technique that defines fetal anatomy and dysmorphology with specific tissue characteristics based on a spin echo sequence using a long repetition time and long echo time. Simple fluid is white (high signal intensity) on a T2-weighted image. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - obgyn.mhmedical.com/content.aspx?aid=1151030271 ER -