title: MRI of frozen tissue demonstrates a phase shift.
abstract: While temperature mapping is desired during cryosurgery for prostate cancer treatment, an effective approach for this purpose is still needed. We have demonstrated a phase shift with temperature in our in vivo canine experiments and ex vivo tissue sample experiments within the frozen tissue. The phase shift is much larger (~0.7 °/°C with an echo time of 0.1 ms at 0.5 T) in magnitude than that predicted by conventional proton resonant frequency shift (0.008 °/°C). It shows little dependence on the echo times used and thus is not due to a frequency change, although frequency-dependent phase shift has been observed near the frozen tissue. This phase shift varies monotonically with temperature within the frozen tissue and therefore may be potentially used as a novel temperature mapping approach in cryoablation applications.
authors.affiliation: Center for MR Research, University of Illinois Medical Center, Chicago, Illinois 60612, USA. aiminglu@uic.edu
authors.forename: Aiming
authors.initials: A
authors.lastname: Lu
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Daniel
authors.forename: Elena
authors.initials: E
authors.lastname: Kaye
authors.forename: Kim
authors.initials: K
authors.lastname: Butts Pauly
mesh_terms: D000818:Animals; D003452:Cryosurgery; D004285:Dogs; D005615:Freezing; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011467:Prostate / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery*; D011468:Prostatectomy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity