Room: Exhibit Hall | Forum 2
Purpose: To develop a method for acquiring mechanical stiffness of tissue in situ using magnetic resonance elastography (MRE) and reliably produce MRE tissue stiffness maps of the liver for patients undergoing stereotactic body radiotherapy (SBRT) for liver cancer.
Methods: An initial cohort of five healthy volunteers were recruited to develop an MRE imaging protocol, identifying proper wave generator position and wave amplitude. Healthy volunteers were each imaged twice, with at least one week between scans, acquiring four axial slices through the liver. Five patients were then imaged, acquiring a four-slice volume encompassing the tumor mass, both before treatment and after delivery of an SBRT treatment course. A custom-built MR safe compression belt with visual biofeedback was used for respiratory motion management and breath hold. Conversion of the MRE wave images to stress maps was performed at the MRI console, using the Philips analysis software. Pre- and post-treatment contours were created by a physician using anatomical image sets acquired during the same imaging session for the patients. Further contours were generated to exclude regions of incomplete data collection.
Results: Healthy volunteers and patients had a mean liver stiffness of 2.15kPa, and 2.84kPa pre-treatment and 3.6kPa post-treatment respectively. The tumor stiffness of the full diseased tissue volume and exclusion contour were 4.02kPa and 4.37kPa pre-treatment, and 2.36kPa and 2.65kPa post-treatment respectively.
Conclusion: The application of MRE allowed for differentiation of healthy and diseased liver tissue. A change in stiffness for diseased tissue from pre- and post-treatment was also observed. The change in tissue stiffness pre- and post-treatment indicates that the SBRT treatment is significantly reducing the stiffness of treated tissue.
Funding Support, Disclosures, and Conflict of Interest: Supported by Institutional Research Grant IRG-14-192-40 from the American Cancer Society
Not Applicable / None Entered.