(Sunday, 7/29/2018) 5:05 PM - 6:00 PM
Room: Karl Dean Ballroom C
Purpose: To develop a method for imaging perfusion-based diffusion and pure diffusion values in tissue utilizing intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI), and evaluate its ability to reliably produce quantitative imaging data using two cohorts. One cohort consisting of five healthy volunteers, and the second of five patients undergoing stereotactic body radiotherapy (SBRT) for cancerous lesions in the liver
Methods: An initial cohort of five healthy volunteers were recruited to develop an IVIM imaging protocol, identifying time requirements and feasibility of acquiring diffusion weighted images with eight unique b-values ranging from 0 to 1000s/mm² (b = 0, 20, 40 ,80, 100, 300, 600, and 1000). Subjects were imaged while maintaining breath hold, using an inhouse compression belt system, which also provided visual biofeedback for breath holds. Healthy volunteers were imaged twice, with at least one week between scans. Five patients were imaged using the developed methodology, and clinical anatomical imaging. Imaging occurred prior to the patients receiving treatment and after SBRT treatment delivery. The IVIM MR images have been analyzed with two unique approaches. The first method (A) utilized only three b-values, as routine DWI data is acquired in the clinic. The second (B) took advantage of all b-value images, and used a biexponential model for fitting diffusion, perfusion, and perfusion fraction. ROIs were created in healthy and diseased tissue for both cohorts, and pre- and post-treatment of patients.
Results: Method A resulted in mean Dfast of 55.6x10�³mm²/s and 77.8x10�³mm²/s and mean Dslow of 0.66x10�³mm²/s and 0.81x10�³mm²/s for diseased tissue pre- and post-treatment respectively. Method B resulted in mean Dfast of 3.00x10�³mm²/s and 5.93x10�³mm²/s and mean Dslow of 0.67x10�³mm²/s and 0.86x10�³mm²/s for diseased tissue pre- and post-treatment respectively.
Conclusion: The developed IVIM imaging methodology allowed acquisition of high quality DW images in a reasonable scanning period.
Funding Support, Disclosures, and Conflict of Interest: Supported by Institutional Research Grant IRG-14-192-40 from the American Cancer Society
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