1. Learning objectives The purpose of our educational exhibit is to: · Describe the basic physics and technical aspects of susceptibility weighted imaging (SWI). · Show the normal SWI appearance, some artefacts and the main limitations. · Review the most important clinical applications of this sequence on intracranial pathology with illustrated examples.

2. Background Susceptibility weighted imaging (SWI) is emerging as a useful technique in a wide variety of intracranial pathologies. The SWI sequences demonstrate high sensitivity to magnetic susceptibility differences of various tissues in particular blood, calcification and haemosiderin. Technical aspects of susceptibility sequences. SWI is a fully velocity-compensated, three-dimensional, gradient-echo sequence that uses both phase and magnitude data to achieve exquisite sensitivity to tissue magnetic susceptibility effects. The phase and magnitude data are acquired separately. The combination of magnitude and phase data produces an enhanced...

3. Findings and procedure details. 1.Cerebral microbleeds (CMB) Cerebral microbleeds are observed in various conditions. Cerebral amyloid angiopathy: It consists of deposition of amyloid protein within the small and medium sized cerebral arteries which is likely responsible for increased vessel fragility with consequent micro and macro haemorrhages demonstrated on SWI with cortical and subcortical distribution. Fig. 7 Chronic hyperintensive encephalopathy (HE): Chronic hyperintensive encephalopathy HE is also characterized by multiple cerebral microbleeds (CMB) which normally are silent. They are usually discovered both in deep basal...

4. Conclusion SWI is a fully velocity three dimensional gradient-echo sequence with exquisite sensitivity to paramagnetic susceptibility effects. It can better demonstrate haemorrhage, venous abdnormalities and mineralisation than conventional sequences. SWI should be include in the routine imaging protocols of trauma and vascular abnormalities. Further investigation is still needed into its extensive application.

5. References 1.Gasparotti R, Pinelli L, Liserre R. Insights Imaging (2011) 2:335-347. New MR sequences in daily practice: susceptibility weigthed omaging. A pictorial essay. 2.Thomas B, Somasundaram S, Thamburaj K, Kesavadas C, Gupta Ak et al.Neuroradiology (2008) 50:105-116. Clinical applications of susceptibility weighted MR imaging of the brain. A pictorial review. 3.Ong BC, Stuckey SL. Journal of Medical Imaging and Radiation Oncology 54 (2010)435-449. Susceptibility weighted imaging: a pictorial review. 4.Sehgal V, Delproposto Z, Haacke EM, Tong KA, Wycliffe N et al. Journal of Magnetic...