Evaluation of Temperature Distribution Around the Probe in Cryoablation of Lipiodol-Mixed-Tissue Phantom.

To determine whether lipiodol, which has low thermal conductivity, influences ice ball formation during cryoablation of a lipiodol-mixed-tissue phantom. Lipiodol-mixed-tissue phantoms were created by injecting lipiodol (4-6 ml) into the renal arteries of ex vivo porcine kidneys (lipiodol group). A cryoprobe (CryoHit™ Needle S) with a holder that was set with thermocouples at various positions around the cryoprobe was inserted. After freezing for 300 s, the followings were evaluated: ice ball size on CT, temperature distribution around the cryoprobe, and calculated distances at 0 °C and - 20 °C. Each variable was compared between lipiodol group (n = 6) those obtained in a control group without lipiodol injection (n = 6). Mean ice ball diameter (width/length) on CT was 22.1 ± 2.3/22.9 ± 2.3 mm in the lipiodol group and 21.6 ± 0.7/22.2 ± 1.3 mm in the control group. Mean cryoprobe temperature was - 118 ± 3.0 °C in the lipiodol group and - 117 ± 2.6 °C in the control group. In both groups, temperature at the 3 mm thermocouple reached approximately - 50 °C and was < 0 °C within ~ 10 mm of the cryoprobe. Temperature of 0/- 20 °C occurred at a mean distance from the cryoprobe of 11.1 ± 0.5/6.9 ± 0.4 mm in the lipiodol group and 11.0 ± 0.2/6.9 ± 0.2 mm in the control group. There was no significant difference in any variable between the groups. The inclusion of lipiodol in a tissue phantom had no negative effects on ice ball formation that were related to thermal conductivity.

Citation

Masanori Yamashita, Hiroshi Miura, Yu Ohara, Tatsuya Yoshikawa, Tatsuya Hirota, Takanobu Fukunaga, Hiroshi Takamatsu, Takuji Yamagami, Kei Yamada. Evaluation of Temperature Distribution Around the Probe in Cryoablation of Lipiodol-Mixed-Tissue Phantom. Cardiovascular and interventional radiology. 2021 Mar;44(3):489-495

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PMID: 33210153

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