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MR‐guided laser‐induced thermotherapy in ex vivo porcine kidney: Comparison of four different imaging sequences
Author(s) -
Vallo Stefan,
Eichler Katrin,
Kelly Kathrin,
Schulz Boris,
Bartsch Georg,
Haferkamp Axel,
Vogl Thomas J,
Zangos Stephan
Publication year - 2014
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.22262
Subject(s) - ablation , nuclear medicine , medicine , ex vivo , laser ablation , magnetic resonance imaging , lesion , catheter ablation , laser , flash (photography) , materials science , radiology , biomedical engineering , in vivo , surgery , optics , physics , biology , microbiology and biotechnology
Purpose To evaluate the clinical value of different magnetic resonance imaging (MRI) sequences for a real‐time thermo‐monitoring during laser‐induced thermotherapy (LITT) in kidneys. Methods Twenty‐eight ex vivo pig kidneys were treated with laser ablation under MR guidance in a high‐field MR scanner (Magnetom Espree or Avanto Fit, Siemens, Germany). For the thermal ablation of the kidney, a neodymium yttrium‐aluminum‐garnet (Nd:YAG) laser was used in combination with a special protective catheter (length 43 cm, 4 French) which is sealed at the distal end. First, ablation was performed for 7, 10, and 13 minutes using FLASH sequences for investigation of time‐dependent growth of lesion size. In the second step, we evaluated the optimal imaging sequence during a 7 minutes ablation of the kidney and after cooling using four different MR sequences (Haste, FLASH, radial VIBE, and Caipirinha DIXON). Results Macroscopic lesion volume increased from 3,784 ± 1,525 mm 3 to 7,683 ± 5,756 mm 3 after the ablation from 7 to 13 minutes and MR volume ranged from 2,107 ± 1,674 mm 3 to 2,934 ± 1,549 mm 3 after the ablation from 7 to 13 minutes. During ablation, FLASH (132 ± 34%) and radial VIBE (120 ± 43%) sequences displayed lesion volumes most efficiently with a trend to overestimation. The Caipirinha DIXON (323 ± 24%) sequence overestimated the volumes significantly during real‐time monitoring. The volumes measured by MRI with FLASH (61 ± 30%), Haste (67 ± 28%), or radial VIBE (48 ± 14%) sequences after cooling of the kidney after ablation were always underestimated. The Caipirinha DIXON (142 ± 2%) sequence still overestimated the lesion volume after cooling of the kidney. Conclusion LITT is a feasible ablation modality in kidney tissue. Moreover, macroscopic and MR lesion volume increases time‐dependently. For online monitoring, radial VIBE and FLASH sequences seem to be most efficient. Lasers Surg. Med. 46:558–562, 2014. © 2014 Wiley Periodicals, Inc.