Review
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Apr 28, 2018; 10(4): 30-45
Published online Apr 28, 2018. doi: 10.4329/wjr.v10.i4.30
Susceptibility weighted imaging: Clinical applications and future directions
Ahmet Mesrur Halefoglu, David Mark Yousem
Ahmet Mesrur Halefoglu, Department of Radiology, Sisli Hamidiye Etfal Training and Research Hospital, University of Health Sciences, Istanbul 34371, Turkey
David Mark Yousem, Division of Neuroradiology, Department of Radiology, Johns Hopkins Medical Institution, Baltimore, MI 21287, United States
Author contributions: All authors equally contributed to this paper with conception and design of the study, literature review and analysis, drafting, critical revision and editing, and final approval of the final version.
Conflict-of-interest statement: No potential conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Ahmet Mesrur Halefoglu, MD, Professor, Department of Radiology, Sisli Hamidiye Etfal Training and Research Hospital, University of Health Sciences, Birlik sok, Parksaray ap, No: 17/4, Istanbul 34371, Turkey. halefoglu@hotmail.com
Telephone: +90-212-3735000 Fax: +90-212-2415015
Received: March 17, 2018
Peer-review started: March 17, 2018
First decision: April 4, 2018
Revised: April 8, 2018
Accepted: April 20, 2018
Article in press: April 20, 2018
Published online: April 28, 2018
Processing time: 72 Days and 3 Hours
Abstract

Susceptibility weighted imaging (SWI) is a recently developed magnetic resonance imaging (MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradient-echo sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.

Keywords: Quantitative susceptibility mapping; Brain; Ischemia; Magnetic resonance imaging; Susceptibility weighted imaging

Core tip: Susceptibility weighted imaging has a variety of applications in neuroradiology practice and should be included in routine protocols. It can detect micro- and macrohemorhages and delineate cerebral microvasculature and can also reveal low-flow vascular malformations. It has been proven as a complementary, valuable imaging sequence in the management of stroke patients. It provides differentiation of calcium from hemorrhage in the brain. It plays an important role in the evaluation of traumatic brain injury patients and aids in the characterization and grading of cerebral tumors. Quantitative susceptibility mapping can be applied on many neurodegenerative disorders by assessing brain iron content.