An analytic method to predict the thermal map of cryosurgery iceballs in MR images

• Published in: IEEE transactions on medical imaging Vol. 23; no. 1; pp. 122 - 129
• Main Authors: Fournial, R., Traore, A.S., Laurendeau, D., Moisan, C.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01-01-2004; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Algorithms; Animals; Body Temperature; Cryogenic temperature; Cryogenics; Cryosurgery - methods; Estimates; Human health and pathology; Ice; Image analysis; Image Interpretation, Computer-Assisted - methods; In Vitro Techniques; Life Sciences; Liquids; Liver; Liver - physiopathology; Liver - surgery; Magnetic analysis; Magnetic resonance; Magnetic Resonance Imaging - instrumentation; Magnetic Resonance Imaging - methods; Mathematical analysis; Medical imaging; Phantoms, Imaging; Phase measurement; Probes; Reproducibility of Results; Sensitivity and Specificity; Solids; Surgery, Computer-Assisted - methods; Swine; Temperature distribution; Temperature sensors; Thermography - instrumentation; Thermography - methods; Time series; temperature mapping; cryotherapy; MR-guided therapy; intraoperative MRI
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/TMI.2003.819919

This paper presents a newly developed method to estimate, in magnetic resonance (MR) images, the temperatures reached within the volume of an iceball produced by a cryogenic probe. Building on the direct measurements of the MR signal intensity and its correlation with independent temperature variations at the phase transition from liquid to solid, the thermal information embedded in the images was accessed. The volume and diameter of the growing iceball were estimated from a time series of MR images. Using regressions over the volume in the time and thermal domains, this method predicted the cryogenic temperatures beyond the range of sensitivity of the MR signal itself. We present a validation of this method in samples of gelatin and ex vivo pig liver. Temperature predictions are shown to agree with independent thermosensor readings over a range extending from 20/spl deg/C down to -65/spl deg/C, with an average error of less than 6/spl deg/C.