Naama Lev-Cohain MD, Presenter: Nothing to Disclose

Takeshi Yokoo MD, PhD, Abstract Co-Author: Nothing to Disclose

Jeffrey Meyer, Abstract Co-Author: Research Grant, Peregrine Pharmaceuticals, Inc

Robert D. Timmerman MD, Abstract Co-Author: Research Grant, Varian Medical Systems, Inc

Ivan Pedrosa MD, Abstract Co-Author: Shareholder, Humana Inc

We report on the characteristic evolution of the intra-lesional and peri-lesional MRI findings after SBRT and their impact on the clinical image interpretations. Teaching points: 1. Intra-lesional and peri-lesional features evolve over the acute, sub-acute and chronic phases after SBRT. These evolving features need to be incorporated in clinical image interpretation. 2. Treated lesions are best identified on the post-contrast T1-weighted images. 3. Intra-lesional restricted diffusion tends to resolve quickly after SBRT. Post-SBRT parenchyma does not demonstrate restricted diffusion. 4. Acute parenchymal changes appear around 3-6 months post-treatment and include peri-lesional and segmental hyper-enhancement and hyper-intensity on T2 weighted images. 5. Subacute parenchymal changes appear around 6 months post-treatment and include increased susceptibility effect due to chronic microhemorrhage. 6. Chronic parenchymal changes develop after 6 months and include biliary dilatation, capsular retraction, and radial stellate enhancement, due to parenchymal scarring.  

1. Background 2. Evolving intra-lesional appearance 3. Evolving peri-lesional appearance 4. Impact on clinical image interpretation

http://abstract.rsna.org/uploads/2014/14005409/14005409_ztkb.pdf

Lev-Cohain, N, Yokoo, T, Meyer, J, Timmerman, R, Pedrosa, I, Evolving MR Imaging Appearance of Post-Radiation Liver Metastases and Parenchyma: A Pictorial Essay.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14005409.html