Majid Chalian MD, Presenter: Nothing to Disclose

Aylin Tekes MD, Abstract Co-Author: Nothing to Disclose

Thierry Huisman MD, Abstract Co-Author: Nothing to Disclose

Susceptibility weighted imaging (SWI) is a new high resolution magnetic resonance imaging (MRI) tool that uses the paramagnetic susceptibility effects of deoxygenated blood to study the intracranial venous vasculature. Because SWI is basically a venous blood oxygen level dependent (BOLD) technique, we sought to explore the value of SWI in identifying critical brain perfusion by focusing on the venous side of brain perfusion.

Axial SWI was added to the standard departmental stroke protocol in children who presented with acute focal neurological deficit suspicious for acute ischemia. In addition, axial T1 and T2-weighted sequences as well as a diffusion tensor imaging (DTI) sequence were measured. Studies were performed on a 1.5 Tesla MRI scanner (Siemens Avanto, Erlangen, Germany). Images were evaluated by two experienced pediatric neuroradiologists in consensus. The SWI images were evaluated for the signal intensity, presence, size and anatomical distribution of intramedullary and sulcal veins. The SWI findings were correlated with the diffusion weighted findings. Follow-up imaging was performed to document brain ischemia/infarction. Institutional IRB was achieved for the use of the SWI sequence in children.

Various patterns of venous drainage could be identified (normal, mildly prominent intramedullary hypointense veins, and prominently hypointense sulcal veins). The constellation of findings on SWI and DWI and the progression of infarction may be explained by the fact that the depending on the degree of hypoperfusion altered levels of oxygen extraction fractions may result in varying degrees of SWI-hypointensity of the draining veins. The appearance of prominent sulcal veins on SWI may serve as an early, easy to collect data set to identify critically perfused tissue at risk for infarction if hypoperfusion persists.

Our study suggests that SWI assisted mapping of the regional changes of the cerebral venous drainage and correlation with diffusion weighted MRI may identify critically perfused brain at risk for infarct progression.

SWI in combination with DTI studies may provide important non-invasive data about critical brain perfusion by focusing on the venous drainage in acute cerebral ischemia.

Chalian, M, Tekes, A, Huisman, T, Added Values of Susceptibility-Weighted Imaging (SWI) for Characterizing Ischemic Brain Injury.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013204.html