TY - JOUR T1 - Susceptibility-Weighted Imaging: Technical Aspects and Clinical Applications, Part 1 JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 19 LP - 30 DO - 10.3174/ajnr.A1400 VL - 30 IS - 1 AU - E.M. Haacke AU - S. Mittal AU - Z. Wu AU - J. Neelavalli AU - Y.-C.N. Cheng Y1 - 2009/01/01 UR - http://www.ajnr.org/content/30/1/19.abstract N2 - SUMMARY: Susceptibility-weighted imaging (SWI) is a new neuroimaging technique, which uses tissue magnetic susceptibility differences to generate a unique contrast, different from that of spin density, T1, T2, and T2*. In this review (the first of 2 parts), we present the technical background for SWI. We discuss the concept of gradient-echo images and how we can measure local changes in susceptibility. Armed with this material, we introduce the steps required to transform the original magnitude and phase images into SWI data. The use of SWI filtered phase as a means to visualize and potentially quantify iron in the brain is presented. Advice for the correct interpretation of SWI data is discussed, and a set of recommended sequence parameters for different field strengths is given. ER -