Junichi Tokuda1, Kemal Tuncali1, Lisanne Kok1,2, Vincent M Levesque 1, Ravi T Seethamraju 3, Clare M Tempany1, and Ehud J Schmidt1
1Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, 2Eindhoven University of Technology, Eindhoven, Netherlands, 3Siemens Healthcare, Boston, MA, United States
We tested the feasibility of R2*-based
temperature mapping using a PETRA UTE sequence to determine the “kill zone” within
an ice ball in the kidney during MRI-guided renal cryoablation. R2*-maps
were calculated from dual-echo PETRA images acquired during six renal cryoablation
cases, and converted to temperature maps using R2*-temperature calibrations
performed in swine kidneys. We compared ablation volumes estimated from (a) the
-20°C boundary on the temperature maps; (b) the signal void on intra-procedural
T2-weighted images; and (c) post-ablation contrast-enhanced MRI as the “gold
standard”. Results show that R2*-based temperature maps provided a reliable
lower limit of the kill-zone volume.
