In vivo evaluation of a MR-guided 980nm laser interstitial thermal therapy system for ablations in porcine liver

Oscar Garcia-Medina, Krzysztof Gorny, Roger McNichols, Jeremy Friese, Sanjay Misra, Kimberly Amrami, Haraldur Bjarnason, Matthew R Callstrom, David A Woodrum

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Purpose To evaluate the use of a 980-nm diode laser for magnetic resonance-guided laser interstitial thermal therapy (MR-guided LITT) ablations in liver tissue in an in vivo porcine model. Materials and methods MR-guided guided LITT was performed on nine juvenile pigs placed under general anesthesia. Target ablation sites were selected in the left and right lobes of the liver. Laser applicators were placed in the liver using intermittent MR guidance. Up to four separate ablations were performed in each animal using a 15 or 30 W laser generator using one or two applicators. During the ablations, continuous MR-based temperature mapping (MR-thermal mapping), using a proton resonance frequency technique, was performed to monitor the size of the ablation in real-time. Extent of thermal tissue damage was continuously estimated based on Arrhenius model. Two-minute ablations were performed at each site. MR-thermal mapping of ablations within the posteroinferior liver were accomplished with continuous breathing at low tidal volume. In the mid right lobe of the liver, due to motion artefacts, MR-thermometry was performed intermittently during breath hold periods. In the left lobe of the liver, ablations were performed with ventilation using positive end expiratory pressure (PEEP) of 10 cm of water. Upon completion, MR imaging with gadolinium contrast was performed to assess the extent of treatment. Thermal lesions were subsequently measured using both, MR-thermal dose and MR gadolinium images, for comparison. Following the animal euthanasia, the liver was harvested and subjected to formalin fixation and paraffin embedding for histological examination. Results Between one and four focal liver ablations (total 24 ablations) were successfully performed in nine animals with either a 15 or 30 W laser generator. For the 15-W laser generator, the average single applicator ablation size was (2.0 ± 0.5) × (2.6 ± 0.4) cm 2, as measured by magnetic resonance (MR) thermometry, or (1.7 ± 0.4) × (2.2 ± 0.6) cm 2, as measured with gadolinium contrast, with the difference being not statistically significant. For the 30-W laser generator, the average single applicator ablation size was (2.4 ± 0.3) × (3.3 ± 0.5) cm 2 by MR thermometry and (2.1 ± 0.4) × (2.9 ± 0.3) cm 2 by gadolinium enhancement, with no statistically significant difference. Simultaneously activating two applicators with the 15 W generator demonstrated ablation sizes of (3.7 ± 0.9) × (3.2 ± 0.1) cm 2 using MR thermometry and (2.3 ± 0.6) × (2.4 ± 0.3) cm 2 with gadolinium contrast, while using two applicators in the 30-W laser generator, yielded (4.5 ± 0.6) × (3.9 ± 0.2) cm 2 using MR thermometry and (4.4 ± 1.1) × (3.6 ± 0.5) cm 2 with gadolinium contrast enhancement. Conclusion In our experience, we found that liver ablations performed with a MR-guided 980-nm diode LITT system through the saline cooled catheter applicator could be performed throughout the liver. Additionally, liver ablations were safe and produced a clinically applicable ablation zone. These results suggest the 980-nm diode laser MR-guided LITT system could be effective in treatments of hepatic tumors.

Original languageEnglish (US)
Pages (from-to)298-305
Number of pages8
JournalLasers in Surgery and Medicine
Volume43
Issue number4
DOIs
StatePublished - Apr 2011

Fingerprint

Lasers
Magnetic Resonance Spectroscopy
Swine
Hot Temperature
Liver
Thermometry
Gadolinium
Therapeutics
Semiconductor Lasers
Animal Euthanasia
Paraffin Embedding
Positive-Pressure Respiration
Tidal Volume
Artifacts
General Anesthesia
Formaldehyde
Ventilation
Protons
Respiration
Catheters

Keywords

  • interventional MRI
  • laser ablation
  • liver
  • MR-guided LITT
  • MRI
  • percutaneous ablation

ASJC Scopus subject areas

  • Surgery
  • Dermatology

Cite this

In vivo evaluation of a MR-guided 980nm laser interstitial thermal therapy system for ablations in porcine liver. / Garcia-Medina, Oscar; Gorny, Krzysztof; McNichols, Roger; Friese, Jeremy; Misra, Sanjay; Amrami, Kimberly; Bjarnason, Haraldur; Callstrom, Matthew R; Woodrum, David A.

In: Lasers in Surgery and Medicine, Vol. 43, No. 4, 04.2011, p. 298-305.

Research output: Contribution to journalArticle

Garcia-Medina, Oscar ; Gorny, Krzysztof ; McNichols, Roger ; Friese, Jeremy ; Misra, Sanjay ; Amrami, Kimberly ; Bjarnason, Haraldur ; Callstrom, Matthew R ; Woodrum, David A. / In vivo evaluation of a MR-guided 980nm laser interstitial thermal therapy system for ablations in porcine liver. In: Lasers in Surgery and Medicine. 2011 ; Vol. 43, No. 4. pp. 298-305.
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T1 - In vivo evaluation of a MR-guided 980nm laser interstitial thermal therapy system for ablations in porcine liver

AU - Garcia-Medina, Oscar

AU - Gorny, Krzysztof

AU - McNichols, Roger

AU - Friese, Jeremy

AU - Misra, Sanjay

AU - Amrami, Kimberly

AU - Bjarnason, Haraldur

AU - Callstrom, Matthew R

AU - Woodrum, David A

PY - 2011/4

Y1 - 2011/4

N2 - Purpose To evaluate the use of a 980-nm diode laser for magnetic resonance-guided laser interstitial thermal therapy (MR-guided LITT) ablations in liver tissue in an in vivo porcine model. Materials and methods MR-guided guided LITT was performed on nine juvenile pigs placed under general anesthesia. Target ablation sites were selected in the left and right lobes of the liver. Laser applicators were placed in the liver using intermittent MR guidance. Up to four separate ablations were performed in each animal using a 15 or 30 W laser generator using one or two applicators. During the ablations, continuous MR-based temperature mapping (MR-thermal mapping), using a proton resonance frequency technique, was performed to monitor the size of the ablation in real-time. Extent of thermal tissue damage was continuously estimated based on Arrhenius model. Two-minute ablations were performed at each site. MR-thermal mapping of ablations within the posteroinferior liver were accomplished with continuous breathing at low tidal volume. In the mid right lobe of the liver, due to motion artefacts, MR-thermometry was performed intermittently during breath hold periods. In the left lobe of the liver, ablations were performed with ventilation using positive end expiratory pressure (PEEP) of 10 cm of water. Upon completion, MR imaging with gadolinium contrast was performed to assess the extent of treatment. Thermal lesions were subsequently measured using both, MR-thermal dose and MR gadolinium images, for comparison. Following the animal euthanasia, the liver was harvested and subjected to formalin fixation and paraffin embedding for histological examination. Results Between one and four focal liver ablations (total 24 ablations) were successfully performed in nine animals with either a 15 or 30 W laser generator. For the 15-W laser generator, the average single applicator ablation size was (2.0 ± 0.5) × (2.6 ± 0.4) cm 2, as measured by magnetic resonance (MR) thermometry, or (1.7 ± 0.4) × (2.2 ± 0.6) cm 2, as measured with gadolinium contrast, with the difference being not statistically significant. For the 30-W laser generator, the average single applicator ablation size was (2.4 ± 0.3) × (3.3 ± 0.5) cm 2 by MR thermometry and (2.1 ± 0.4) × (2.9 ± 0.3) cm 2 by gadolinium enhancement, with no statistically significant difference. Simultaneously activating two applicators with the 15 W generator demonstrated ablation sizes of (3.7 ± 0.9) × (3.2 ± 0.1) cm 2 using MR thermometry and (2.3 ± 0.6) × (2.4 ± 0.3) cm 2 with gadolinium contrast, while using two applicators in the 30-W laser generator, yielded (4.5 ± 0.6) × (3.9 ± 0.2) cm 2 using MR thermometry and (4.4 ± 1.1) × (3.6 ± 0.5) cm 2 with gadolinium contrast enhancement. Conclusion In our experience, we found that liver ablations performed with a MR-guided 980-nm diode LITT system through the saline cooled catheter applicator could be performed throughout the liver. Additionally, liver ablations were safe and produced a clinically applicable ablation zone. These results suggest the 980-nm diode laser MR-guided LITT system could be effective in treatments of hepatic tumors.

AB - Purpose To evaluate the use of a 980-nm diode laser for magnetic resonance-guided laser interstitial thermal therapy (MR-guided LITT) ablations in liver tissue in an in vivo porcine model. Materials and methods MR-guided guided LITT was performed on nine juvenile pigs placed under general anesthesia. Target ablation sites were selected in the left and right lobes of the liver. Laser applicators were placed in the liver using intermittent MR guidance. Up to four separate ablations were performed in each animal using a 15 or 30 W laser generator using one or two applicators. During the ablations, continuous MR-based temperature mapping (MR-thermal mapping), using a proton resonance frequency technique, was performed to monitor the size of the ablation in real-time. Extent of thermal tissue damage was continuously estimated based on Arrhenius model. Two-minute ablations were performed at each site. MR-thermal mapping of ablations within the posteroinferior liver were accomplished with continuous breathing at low tidal volume. In the mid right lobe of the liver, due to motion artefacts, MR-thermometry was performed intermittently during breath hold periods. In the left lobe of the liver, ablations were performed with ventilation using positive end expiratory pressure (PEEP) of 10 cm of water. Upon completion, MR imaging with gadolinium contrast was performed to assess the extent of treatment. Thermal lesions were subsequently measured using both, MR-thermal dose and MR gadolinium images, for comparison. Following the animal euthanasia, the liver was harvested and subjected to formalin fixation and paraffin embedding for histological examination. Results Between one and four focal liver ablations (total 24 ablations) were successfully performed in nine animals with either a 15 or 30 W laser generator. For the 15-W laser generator, the average single applicator ablation size was (2.0 ± 0.5) × (2.6 ± 0.4) cm 2, as measured by magnetic resonance (MR) thermometry, or (1.7 ± 0.4) × (2.2 ± 0.6) cm 2, as measured with gadolinium contrast, with the difference being not statistically significant. For the 30-W laser generator, the average single applicator ablation size was (2.4 ± 0.3) × (3.3 ± 0.5) cm 2 by MR thermometry and (2.1 ± 0.4) × (2.9 ± 0.3) cm 2 by gadolinium enhancement, with no statistically significant difference. Simultaneously activating two applicators with the 15 W generator demonstrated ablation sizes of (3.7 ± 0.9) × (3.2 ± 0.1) cm 2 using MR thermometry and (2.3 ± 0.6) × (2.4 ± 0.3) cm 2 with gadolinium contrast, while using two applicators in the 30-W laser generator, yielded (4.5 ± 0.6) × (3.9 ± 0.2) cm 2 using MR thermometry and (4.4 ± 1.1) × (3.6 ± 0.5) cm 2 with gadolinium contrast enhancement. Conclusion In our experience, we found that liver ablations performed with a MR-guided 980-nm diode LITT system through the saline cooled catheter applicator could be performed throughout the liver. Additionally, liver ablations were safe and produced a clinically applicable ablation zone. These results suggest the 980-nm diode laser MR-guided LITT system could be effective in treatments of hepatic tumors.

KW - interventional MRI

KW - laser ablation

KW - liver

KW - MR-guided LITT

KW - MRI

KW - percutaneous ablation

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