New MR sequences in daily practice: susceptibility weighted imaging. A pictorial essayReport as inadecuate

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Insights into Imaging

, Volume 2, Issue 3, pp 335–347

First Online: 26 March 2011Received: 13 August 2010Revised: 22 November 2010Accepted: 15 February 2011


BackgroundSusceptibility-weighted imaging SWI is a relatively new magnetic resonance MR technique that exploits the magnetic susceptibility differences of various tissues, such as blood, iron and calcification, as a new source of contrast enhancement. This pictorial review is aimed at illustrating and discussing its main clinical applications.

MethodsSWI is based on high-resolution, three-dimensional 3D, fully velocity-compensated gradient-echo sequences using both magnitude and phase images. A phase mask obtained from the MR phase images is multiplied with magnitude images in order to increase the visualisation of the smaller veins and other sources of susceptibility effects, which are displayed at best after post-processing of the 3D dataset with the minimal intensity projection minIP algorithm.

ResultsSWI is very useful in detecting cerebral microbleeds in ageing and occult low-flow vascular malformations, in characterising brain tumours and degenerative diseases of the brain, and in recognizing calcifications in various pathological conditions. The phase images are especially useful in differentiating between paramagnetic susceptibility effects of blood and diamagnetic effects of calcium. SWI can also be used to evaluate changes in iron content in different neurodegenerative disorders.

ConclusionSWI is useful in differentiating and characterising diverse brain disorders.

KeywordsBrain Magnetic resonance imaging Susceptibility weighted imaging  Download fulltext PDF

Author: Roberto Gasparotti - Lorenzo Pinelli - Roberto Liserre


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