Assessment of irrigation dynamics in magnetic-resonance guided laser induced thermal therapy (MRgLITT)

Sinha, Saurabh; Hargreaves, Eric L.; Patel, Nitesh V; Danish, Shabbar F.

doi:10.1002/lsm.22332

Cited by 9 publications

(6 citation statements)

References 21 publications

(34 reference statements)

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“…Moving forward, there will need to be some attention paid to this variable, as it can be adjusted by the user during the procedure. 28 A final limitation of this study is that the data reported were acquired using the Visualase MRI-guided laser ablation technology. The Monteris NeuroBlate ablation system is another system approved for intracranial ablation; however, this system utilizes a different catheter design, thermal damage threshold temperature, and laser wavelength.…”

Section: Discussionmentioning

confidence: 99%

Ablation dynamics of subsequent thermal doses delivered to previously heat-damaged tissue during magnetic resonance–guided laser-induced thermal therapy

Munier¹,

Hargreaves²,

Patel³

et al. 2019

Journal of Neurosurgery

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OBJECTIVEIntraoperative dynamics of magnetic resonance–guided laser-induced thermal therapy (MRgLITT) have been previously characterized for ablations of naive tissue. However, most treatment sessions require the delivery of multiple doses, and little is known about the ablation dynamics when additional doses are applied to heat-damaged tissue. This study investigated the differences in ablation dynamics between naive versus damaged tissue.METHODSThe authors examined 168 ablations from 60 patients across various surgical indications. All ablations were performed using the Visualase MRI-guided laser ablation system (Medtronic), which employs a 980-nm diffusing tip diode laser. Cases with multiple topographically overlapping doses with constant power were selected for this study. Single-dose intraoperative thermal damage was used to calculate ablation rate based on the thermal damage estimate (TDE) of the maximum area of ablation achieved (TDEmax) and the total duration of ablation (tmax). We compared ablation rates of naive undamaged tissue and damaged tissue exposed to subsequent thermal doses following an initial ablation.RESULTSTDEmax was significantly decreased in subsequent ablations compared to the preceding ablation (initial ablation 227.8 ± 17.7 mm2, second ablation 164.1 ± 21.5 mm2, third ablation 124.3 ± 11.2 mm2; p = < 0.001). The ablation rate of subsequent thermal doses delivered to previously damaged tissue was significantly decreased compared to the ablation rate of naive tissue (initial ablation 2.703 mm2/sec; second ablation 1.559 mm2/sec; third ablation 1.237 mm2/sec; fourth ablation 1.076 mm/sec; p = < 0.001). A negative correlation was found between TDEmax and percentage of overlap in a subsequent ablation with previously damaged tissue (r = −0.164; p < 0.02).CONCLUSIONSAblation of previously ablated tissue results in a reduced ablation rate and reduced TDEmax. Additionally, each successive thermal dose in a series of sequential ablations results in a decreased ablation rate relative to that of the preceding ablation. In the absence of a change in power, operators should anticipate a possible reduction in TDE when ablating partially damaged tissue for a similar amount of time compared to the preceding ablation.

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Section: Discussionmentioning

confidence: 99%

Ablation dynamics of subsequent thermal doses delivered to previously heat-damaged tissue during magnetic resonance–guided laser-induced thermal therapy

Munier¹,

Hargreaves²,

Patel³

et al. 2019

Journal of Neurosurgery

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“…As previously noted, the irrigation rate was set between levels 1 and 2 in each of the 93 cases analysed. A previous study investigated the flow rate through the cooling catheter at each pump setting available (levels l-10), finding that rate of flow increases non-linearly with pump setting [13]. However, it is still presently unknown whether ablation dynamics are affected within this small range of irrigation rate variability.…”

Section: Discussionmentioning

confidence: 99%

“…However, it is still presently unknown whether ablation dynamics are affected within this small range of irrigation rate variability. Moving forward, there will need to be some attention paid to this variable, as it can be adjusted by the user during the procedure [13].…”

Section: Discussionmentioning

confidence: 99%

“…The ability to monitor therapy in real time allows for strict control of the ablation area, and many previously inoperable lesions are now treatable with MRgLITT [3][4][5]. To date, MRgLITT has been successfully applied in the treatment of many intracranial pathologies, including glioblastoma multiforme (GBM) [6], ependymomas [6], epilepsy [7][8][9][10], metastatic tumours [6,11,12] and intractable pain [13]. Currently, there are two laser ablation systems approved for intracranial soft-tissue ablation: the Medtronic Visualase system (Medtronic Inc, Minneapolis, MN) and the Monteris NeuroBlate system (Monteris Medical, Plymouth, MN).…”

Section: Introductionmentioning

confidence: 99%

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Effects of variable power on tissue ablation dynamics during magnetic resonance-guided laser-induced thermal therapy with the Visualase system

Munier

Hargreaves

Patel

et al. 2017

International Journal of Hyperthermia

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“…Another important technique using the modeling of light due to the laser illumination is laser induced thermal ablation therapy [15][16][17][18]. This treatment method is a minimally invasive and alternative technique to the conventional surgery and can provide faster recovery times as well as less complication rates [19][20][21]. The increased temperature due to light absorption also promotes the tumor destruction.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive analytical model for CW laser induced heat in turbid media

Erkol¹,

Nouizi²,

Luk³

et al. 2015

Opt. Express

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In this work, we present a new analytical approach to model continuous wave laser induced temperature in highly homogeneous turbid media. First, the diffusion equation is used to model light transport and a comprehensive solution is derived analytically by obtaining a special Greens' function. Next, the time-dependent bio-heat equation is used to describe the induced heat increase and propagation within the medium. The bio-heat equation is solved analytically utilizing the separation of variables technique. Our theoretical model is successfully validated using numerical simulations and experimental studies with agarose phantoms and ex-vivo chicken breast samples. The encouraging results show that our method can be implemented as a simulation tool to determine important laser parameters that govern the magnitude of temperature rise within homogenous biological tissue or organs.

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Assessment of irrigation dynamics in magnetic-resonance guided laser induced thermal therapy (MRgLITT)

Cited by 9 publications

References 21 publications

Ablation dynamics of subsequent thermal doses delivered to previously heat-damaged tissue during magnetic resonance–guided laser-induced thermal therapy

Ablation dynamics of subsequent thermal doses delivered to previously heat-damaged tissue during magnetic resonance–guided laser-induced thermal therapy

Effects of variable power on tissue ablation dynamics during magnetic resonance-guided laser-induced thermal therapy with the Visualase system

Comprehensive analytical model for CW laser induced heat in turbid media

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