Room: Exhibit Hall | Forum 6
Purpose: To develop fluorine-19 MRI (Â¹â?¹F-MRI) to assess spatial distribution and relative concentration of trifluoroacetic acid (TFA), a novel chemoablation agent under development as a treatment for hepatocellular carcinoma. Â¹â?¹F has no biological background, allowing very low concentrations of Â¹â?¹F to be detected.
Methods: Increasing concentrations of TFA were injected into ex-vivo porcine liver as an ablation agent (100Î¼L of 0.25M, 0.5M, 1.0M, and 10.0M). Â¹â?¹F-MRI was performed on a 7 T Biospec USR 70/30 (Bruker Corp.; Billerica, MA) using a custom-built Â¹â?¹F volume coil (RAPID MR International; Columbus, OH) tuned to 282.56 MHz. Â¹â?¹F images were acquired with a rapid acquisition relaxation enhancement (RARE) sequence optimized for the relaxation properties of TFA. Parameters included a 5 second repetition time, 32 x 32 matrix, 30 mm x 30 mm field-of-view, 5 mm slice thickness, 64 averages, and echo train length of 17. Total acquisition time was 5 minutes and 35 seconds for each image. Â¹â?¹F MRI images were superimposed on similarly acquired proton images. Tissue samples were then fixated in formalin and prepared for histological H&E (hematoxylin and eosin) staining.
Results: TFA was successfully imaged at all concentrations with adequate SNR (ranging from SNR=8 for 0.25M to SNR=180 for 10.0M). Â¹â?¹F image SNR increased with increasing TFA concentration. H&E staining showed areas of ablated tissue within each sample.
Conclusion: Results demonstrate that Â¹â?¹F-MRI can be used to image the distribution of TFA in tissue, even at low concentrations. This enables visualization of the ablated areas and provides evidence that comparing relative TFA concentration to tissue damage from ablation is feasible. Future studies will develop metrics to further improve quantification of TFA concentration and biodistribution after injection in tissue.