H.S. Kim, G.-H. Jahng, C.W. Ryu, and S.Y. Kim. Added Value and Diagnostic Performance of Intratumoral Susceptibility Signals in the Differential Diagnosis of Solitary Enhancing Brain Lesions: Preliminary Study.  AJNR Am J Neuroradiol first published on May 20, 2009 as doi: 10.3174/ajnr.A1635

This is a great article that shows how susceptibility-weighted imaging (SWI) can improve the diagnostic performance of MRI in distinguishing GBM from other solitary enhancing lesions such as metastasis and lymphoma. High grade gliomas have more intratumoral susceptibility hypointense signals than other types of lesions, probably due to large amounts of deoxyhemoglobin related to increased blood supply, as well as microhemorrhage.

At our institution, we have had the original SWI sequence since 2001, implemented on our 1.5T scanners for many years, and now installed on our 3.0T scanners. Although the original sequence at 1.5 T takes almost 10 minutes (the sequence is faster, under 5 minutes, on the 3.0T scanners), we quickly began including it as a sequence in our routine brain protocol, especially given the wholehearted support from our referring clinicians. Although we are an academic hospital with 7 MRI scanners, and can “afford” the extra time to acquire SWI, we feel that the value of SWI justifies the inclusion of this sequence routinely, at all imaging centers. We have performed over 6000 SWI studies since 2001, and have seen it improve our diagnosis and evaluation of traumatic brain injury, hemorrhage in infarcts, venous thrombosis, hypoxic-ischemic injury, tumors, slow-flow vascular malformations, amyloid angiopathy, coagulopathy, iron deposition disorders, etc. The increased sensitivity of SWI to microhemorrhage, venous vascularity, calcification and iron deposition enables better characterization of brain lesions. There are still some areas for improvement of SWI, such as standardization across manufacturers, faster acquisition times, and decreased artifact from the skull base and osseous structures of the spine. However, we are excited with the increasing use of SWI at other sites across the world, and look forward to other users validating the utility of this sequence, further technical improvements, and ultimately its widespread use.