Magnetic resonance imaging of frozen tissues: temperature-dependent MR signal characteristics and relevance for MR monitoring of cryosurgery.
Previously, the magnetic resonance (MR) imaging appearance of frozen tissues created during cryosurgery has been described as a signal void. In this work, very short echo times (1.2 msec) allowed MR signals from frozen tissues to be measured at temperatures down to -35 degrees C. Ex vivo bovine liver, muscle, adipose tissue, and water were imaged at steady-state temperatures from -78 degrees to +6 degrees C. Signal intensity, T2*, and T1 were measured using gradient-echo imaging. Signal intensity and T2* decrease monotonically with temperature. In the future, these MR parameters may be useful for mapping temperatures during cryosurgery.
Daniel
B L
BL
Department of Radiology, Lucas MRS/I Center, Stanford University, California 94305-5488, USA. bdaniel@s-word.stanford.edu
Butts
K
K
Block
W F
WF
D000273:Adipose Tissue / Q000033:anatomy & histology*; D000818:Animals; D002417:Cattle; D003452:Cryosurgery; D046508:Culture Techniques; D005615:Freezing; D008099:Liver / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D016343:Monitoring, Intraoperative / Q000295:instrumentation; D018482:Muscle, Skeletal / Q000033:anatomy & histology*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013696:Temperature