title: Temperature isotherms during pulmonary cryoablation and their correlation with the zone of ablation.
abstract: OBJECTIVE
  To determine the expected ablation zone size and associated isotherms when using clinically available percutaneous cryoprobes for pulmonary cryoablation in a porcine lung model.
  
  
  METHODS
  Seven ablations were performed in the lungs of three adult pigs using clinically available 2.4-mm cryoprobes (Endocare, Inc, Irvine, California) and a 10-minute double-freeze protocol. Five 18-gauge thermocouples were positioned at 5-mm increments (ie, 5, 10, 15, 20, and 25 mm) from the cryoprobe. Real-time tissue temperatures were recorded during the cryoablation. The isotherms obtained during the ablation and the pathological ablation zones were measured.
  
  
  RESULTS
  The pathologic zone of complete necrosis had a mean diameter of 2.4 + or - 0.2 cm, with a mean area of 4.6 + or - 0.6 cm(2) and a circularity of 0.95 + or - 0.04. In comparison, the mean diameter (+ or - standard deviation) of the 0 degrees C, -20 degrees C, and -40 degrees C isotherms were 3.1 + or - 0.2 cm, 2.3 + or - 0.3 cm, and 1.8 + or - 0.4 cm, respectively. The -20 degrees C isotherm was most closely related to the pathologic zone of ablation.
  
  
  CONCLUSIONS
  This study establishes the temperature isotherms and associated ablation zone size that can be expected with modern percutaneous cryoprobes in an in vivo porcine lung model.
authors.affiliation: University of Wisconsin Department of Radiology, E3/311 CSC, 600 Highland Avenue, Madison, WI 53792, USA. jhinshaw@uwhealth.org
authors.forename: J Louis
authors.initials: JL
authors.lastname: Hinshaw
authors.forename: Fred T
authors.initials: FT
authors.lastname: Lee
authors.forename: Paul F
authors.initials: PF
authors.lastname: Laeseke
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Sampson
authors.forename: Christopher
authors.initials: C
authors.lastname: Brace
mesh_terms: D000818:Animals; D003080:Cold Temperature; D003452:Cryosurgery / Q000295:instrumentation; D004867:Equipment Design; D005260:Female; D008168:Lung / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D009336:Necrosis; D034421:Sus scrofa; D013997:Time Factors