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Lombardi S, Tortora D, Picariello S, Sudhakar S, De Vita E, Mankad K, Varadkar S, Consales A, Nobili L, Cooper J, Tisdall MM, D'Arco F. Intraoperative MRI Assessment of the Tissue Damage during Laser Ablation of Hypothalamic Hamartoma. Diagnostics (Basel) 2023; 13:2331. [PMID: 37510075 PMCID: PMC10378573 DOI: 10.3390/diagnostics13142331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/29/2023] [Accepted: 07/03/2023] [Indexed: 07/30/2023] Open
Abstract
Laser ablation for treatment of hypothalamic hamartoma (HH) is a minimally invasive and effective technique used to destroy hamartomatous tissue and disconnect it from the functioning brain. Currently, the gold standard to evaluate the amount of tissue being "burned" is the use of heat maps during the ablation procedure. However, these maps have low spatial resolution and can be misleading in terms of extension of the tissue damage. The aim of this study is to use different MRI sequences immediately after each laser ablation and correlate the extension of signal changes with the volume of malacic changes in a long-term follow-up scan. During the laser ablation procedure, we imaged the hypothalamic region with high-resolution axial diffusion-weighted images (DWI) and T2-weighted images (T2WI) after each ablation. At the end of the procedure, we also added a post-contrast T1-weighted image (T1WI) of the same region. We then correlated the product of the maximum diameters on axial showing signal changes (acute oedema on T2WI, DWI restriction rim, DWI hypointense core and post-contrast T1WI rim) with the product of the maximum diameters on axial T2WI of the malacic changes in the follow-up scan, both as a fraction of the total area of the hamartoma. The area of the hypointense core on DWI acquired immediately after the laser ablation statistically correlated better with the final area of encephalomalacia, while the T2WI, hyperintense oedema, DWI rim and T1WI rim of enhancement tended to overestimate the encephalomalacic damage. In conclusion, the use of intraoperative sequences (in particular DWI) during laser ablation can give surgeons valuable information in real time about the effective heating damage on the hamartomatous tissue, with better spatial resolution in comparison to the thermal maps.
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Affiliation(s)
- Sophie Lombardi
- Radiodiagnostic Department, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy
| | - Domenico Tortora
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Stefania Picariello
- Neuro-Oncology Unit, Department of Paediatric Oncology, Santobono-Pausilipon Children's Hospital, 80123 Naples, Italy
| | - Sniya Sudhakar
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Enrico De Vita
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Kshitij Mankad
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Sophia Varadkar
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Alessandro Consales
- Department of Surgical Sciences, Division of Neurosurgery, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Lino Nobili
- Child Neuropsychiatry Unit, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Jessica Cooper
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Martin M Tisdall
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Felice D'Arco
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
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Vincelette RL, Curran MP, Danish SF, Grissom WA. Appearance and modeling of bubble artifacts in intracranial magnetic resonance-guided laser interstitial thermal therapy (MRg-LITT) temperature images. Magn Reson Imaging 2023; 101:67-75. [PMID: 37011772 DOI: 10.1016/j.mri.2023.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/30/2023] [Indexed: 04/04/2023]
Abstract
PURPOSE To understand if unexplained signal artifacts in MRg-LITT proton resonance frequency- (PRF-) shift thermometry images are caused by air bubbles or hemorrhages, and to characterize their effects on temperature measurements. METHODS Retrospective image data from an IRB-approved clinical trial of intracranial MRg-LITT were inspected for asymmetric distortions observed in phase data during ablations, which have been previously reported as likely hemorrhages. A total of eight patient cases were selected: seven with artifact occurrence and one without. Mathematical image models for air bubbles or hemorrhages were implemented to estimate the size of the air bubble or hemorrhage needed to explain the clinically observed phase artifacts. Correlations and Bland-Altman analyses were used to determine if an air bubble model or a hemorrhage model was better correlated to the clinical data. The model was used to inject bubbles into clean PRF phase data without artifacts to examine how temperature profile distortions change with slice orientation. The simulated air-bubble injected data were compared to clinical data containing artifacts to examine the bubbles' effects on temperature and thermal damage estimates. RESULTS The model demonstrated that air bubbles up to approximately 1 cm in diameter could explain the clinically observed phase artifacts. The bubble model predicts that a hemorrhage would have to be 2.2 times as large as an air bubble in order to explain the same extent of phase distortion observed in clinical data. Air bubbles had 16% percent higher correlations to the clinical PRF phase data than hemorrhages, even after rescaling the hemorrhage phases to better match the data. The air bubble model also explains how the phase artifacts lead to both large positive and large negative temperature errors, up to ±100 °C, which could cascade to damage estimate errors of several millimeters. CONCLUSION Results showed that the artifacts are likely caused by air bubbles rather than hemorrhages, which may be introduced before heating or appear during heating. Manufacturers and users of devices that rely upon PRF-shift thermometry should be aware these phase distortions from bubble artifacts can result in large temperature errors.
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Gajjar AA, Huy Dinh Le A, Swaroop Lavadi R, Boddeti U, Barpujari A, Agarwal N. Evolution of Robotics in Neurosurgery: A Historical Perspective. INTERDISCIPLINARY NEUROSURGERY 2023. [DOI: 10.1016/j.inat.2023.101721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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De Landro M, Pietra FL, Pagotto SM, Porta L, Staiano I, Giraudeau C, Verde J, Ambarki K, Bianchi L, Korganbayev S, Odeen H, Gallix B, Saccomandi P. Analysis of cavitation artifacts in Magnetic Resonance Imaging Thermometry during laser ablation monitoring. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:5008-5011. [PMID: 36085902 DOI: 10.1109/embc48229.2022.9871675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Magnetic Resonance Thermometry Imaging (MRTI) holds great potential in laser ablation (LA) monitoring. It provides the real-time multidimensional visualization of the treatment effect inside the body, thus enabling accurate intraoperative prediction of the thermal damage induced. Despite its great potential., thermal maps obtained with MRTI may be affected by numerous artifacts. Among the sources of error producing artifacts in the images., the cavitation phenomena which could occur in the tissue during LA induces dipole-structured artifacts. In this work., an analysis of the cavitation artifacts occurring during LA in a gelatin phantom in terms of symmetry in space and symmetry of temperature values was performed. Results of 2 Wand 4 W laser power were compared finding higher symmetry for the 2 W case in terms of both dimensions of artifact-lobes and difference in temperature values extracted in specular pixels in the image. This preliminary investigation of artifact features may provide a step forward in the identification of the best strategy to correct and avoid artifact occurrence during thermal therapy monitoring. Clinical Relevance- This work presents an analysis of cavitation artifacts in MRTI from LA which must be corrected to avoid error in the prediction of thermal damage during LA monitoring.
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Liang AS, Munier SM, Danish SF. Controlling Signal Artifact With Software Threshold Imaging for Magnetic Resonance-Guided Laser Interstitial Thermal Therapy. Oper Neurosurg (Hagerstown) 2022; 22:75-79. [PMID: 35007257 DOI: 10.1227/ons.0000000000000045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 09/01/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) uses intraoperative temperature mapping and thermal damage estimates to guide ablations of intracranial targets. In select cases, signal artifact presents at the target site and impairs intraprocedural decision-making by obscuring the visualization of both temperature imaging and the thermal damage estimate calculation. To date, the etiology and impact of signal artifact are unknown. However, user-selected MRgLITT software settings may play a role in generating artifact. OBJECTIVE To assess the effect of the thresholding feature in MRgLITT software on signal artifact generation during intracranial ablations. METHODS Ablations were performed with the Visualase MRI-guided Laser Ablation System (Medtronic). For each LITT procedure, raw thermal data were extracted at a reference threshold of 40 and reprocessed at 5 additional threshold values ranging from 35 to 60. Artifact growth rates relative to threshold values were derived using simple linear regressions and then assessed within the context of laser power and duration using Pearson correlations. RESULTS A total of 33 patients were included, with 28 artifact-containing and 5 artifact-free cases. For artifact-containing cases, a 13% increase in artifact area occurred for every 1-point increase in threshold (R2 > 0.99). Artifact growth rates were not correlated with laser power (r = 0.15, P = .44) or duration (r = 0.0049, P = .98). One of the 5 artifact-free cases developed artifact at a threshold of 60. CONCLUSION Artifact generation is likely multifactorial involving tissue properties and software settings. Operators can minimize software-introduced artifact by reducing threshold values.
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Affiliation(s)
- Allison S Liang
- Department of Neurological Surgery, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, USA
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Noh T, Juvekar P, Huang R, Lee G, Ogasawara CT, Golby AJ. Biopsy Artifact in Laser Interstitial Thermal Therapy: A Technical Note. Front Oncol 2021; 11:746416. [PMID: 34868945 PMCID: PMC8637457 DOI: 10.3389/fonc.2021.746416] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/28/2021] [Indexed: 11/25/2022] Open
Abstract
Purpose The safety and effectiveness of laser interstitial thermal therapy (LITT) relies critically on the ability to continuously monitor the ablation based on real-time temperature mapping using magnetic resonance thermometry (MRT). This technique uses gradient recalled echo (GRE) sequences that are especially sensitive to susceptibility effects from air and blood. LITT for brain tumors is often preceded by a biopsy and is anecdotally associated with artifact during ablation. Thus, we reviewed our experience and describe the qualitative signal dropout that can interfere with ablation. Methods We retrospectively reviewed all LITT cases performed in our intraoperative MRI suite for tumors between 2017 and 2020. We identified a total of 17 LITT cases. Cases were reviewed for age, sex, pathology, presence of artifact, operative technique, and presence of blood/air on post-operative scans. Results We identified six cases that were preceded by biopsy, all six had artifact present during ablation, and all six were noted to have air/blood on their post-operative MRI or CT scans. In two of those cases, the artifactual signal dropout qualitatively interfered with thermal damage thresholds at the borders of the tumor. There was no artifact in the 11 non-biopsy cases and no obvious blood or air was noted on the post-ablation scans. Conclusion Additional consideration should be given to pre-LITT biopsies. The presence of air/blood caused an artifactual signal dropout effect in cases with biopsy that was severe enough to interfere with ablation in a significant number of those cases. Additional studies are needed to identify modifying strategies.
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Affiliation(s)
- Thomas Noh
- Division of Neurosurgery, John A Burns School of Medicine, Honolulu, HI, United States
| | - Parikshit Juvekar
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Raymond Huang
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Gunnar Lee
- Division of Neurosurgery, John A Burns School of Medicine, Honolulu, HI, United States
| | - Christian T Ogasawara
- Division of Neurosurgery, John A Burns School of Medicine, Honolulu, HI, United States
| | - Alexandra J Golby
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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Prediction of In Vivo Laser-Induced Thermal Damage with Hyperspectral Imaging Using Deep Learning. SENSORS 2021; 21:s21206934. [PMID: 34696147 PMCID: PMC8539534 DOI: 10.3390/s21206934] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/11/2021] [Accepted: 10/15/2021] [Indexed: 12/26/2022]
Abstract
Thermal ablation is an acceptable alternative treatment for primary liver cancer, of which laser ablation (LA) is one of the least invasive approaches, especially for tumors in high-risk locations. Precise control of the LA effect is required to safely destroy the tumor. Although temperature imaging techniques provide an indirect measurement of the thermal damage, a degree of uncertainty remains about the treatment effect. Optical techniques are currently emerging as tools to directly assess tissue thermal damage. Among them, hyperspectral imaging (HSI) has shown promising results in image-guided surgery and in the thermal ablation field. The highly informative data provided by HSI, associated with deep learning, enable the implementation of non-invasive prediction models to be used intraoperatively. Here we show a novel paradigm “peak temperature prediction model” (PTPM), convolutional neural network (CNN)-based, trained with HSI and infrared imaging to predict LA-induced damage in the liver. The PTPM demonstrated an optimal agreement with tissue damage classification providing a consistent threshold (50.6 ± 1.5 °C) for the damage margins with high accuracy (~0.90). The high correlation with the histology score (r = 0.9085) and the comparison with the measured peak temperature confirmed that PTPM preserves temperature information accordingly with the histopathological assessment.
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Liang AS, Munier SM, Danish SF. Mathematical Modeling of Thermal Damage Estimate Volumes in MR-guided Laser Interstitial Thermal Therapy. J Neuroimaging 2021; 31:334-340. [PMID: 33471941 DOI: 10.1111/jon.12830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive procedure that produces real-time thermal damage estimates (TDEs) of ablation. Currently, MRgLITT software provides limited quantitative parameters for intraoperative monitoring, but orthogonal TDE-MRI slices can be utilized to mathematically estimate ablation volume. The objective of this study was to model TDE volumes and validate using post-24 hours MRI ablative volumes. METHODS Ablations were performed with the Visualase Laser Ablation System (Medtronic). Using ellipsoidal parameters determined for dual-TDEs from orthogonal MRI planes, TDE volumes were calculated by two definite integral methods (A and B) implemented in Matlab (MathWorks). Post-24 hours MRI ablative volumes were measured in OsiriX (Pixmeo) by two-blinded raters and compared to TDE volumes via paired t-test and Pearson's correlations. RESULTS Twenty-two ablations for 20 patients with various intracranial pathologies were included. Average TDE volume calculated with method A was 3.44 ± 1.96 cm3 and with method B was 4.83 ± 1.53 cm3 . Method A TDE volumes were significantly different than post-24 hours volumes (P < .001). Method B TDE volumes were not significantly different than post-24 hours volumes (P = .39) and strongly correlated with each other (r = .85, R2 = .72, P < .0001). A total of eight of 22 (36%) method A versus 17 of 22 (77%) method B TDE volumes were within 25% of the post-24 hours ablative volume. CONCLUSION We present a viable mathematical method integrating dual-plane TDEs to calculate volumes. Future algorithmic iterations will incorporate additional calculated variables that improve ablative volume estimations.
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Affiliation(s)
- Allison S Liang
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Sean M Munier
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
| | - Shabbar F Danish
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ
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Blackwell J, Kraśny MJ, O'Brien A, Ashkan K, Galligan J, Destrade M, Colgan N. Proton Resonance Frequency Shift Thermometry: A Review of Modern Clinical Practices. J Magn Reson Imaging 2020; 55:389-403. [PMID: 33217099 DOI: 10.1002/jmri.27446] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/02/2020] [Accepted: 11/02/2020] [Indexed: 12/22/2022] Open
Abstract
Magnetic resonance imaging (MRI) has become a popular modality in guiding minimally invasive thermal therapies, due to its advanced, nonionizing, imaging capabilities and its ability to record changes in temperature. A variety of MR thermometry techniques have been developed over the years, and proton resonance frequency (PRF) shift thermometry is the current clinical gold standard to treat a variety of cancers. It is used extensively to guide hyperthermic thermal ablation techniques such as high-intensity focused ultrasound (HIFU) and laser-induced thermal therapy (LITT). Essential attributes of PRF shift thermometry include excellent linearity with temperature, good sensitivity, and independence from tissue type. This noninvasive temperature mapping method gives accurate quantitative measures of the temperature evolution inside biological tissues. In this review, the current status and new developments in the fields of MR-guided HIFU and LITT are presented with an emphasis on breast, prostate, bone, uterine, and brain treatments. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.
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Affiliation(s)
- James Blackwell
- Advanced Biological Imaging Laboratory, School of Physics, National University of Ireland Galway, Galway, Ireland.,School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland
| | - Marcin J Kraśny
- Advanced Biological Imaging Laboratory, School of Physics, National University of Ireland Galway, Galway, Ireland
| | - Aoife O'Brien
- School of Psychology, National University of Ireland Galway, Galway, Ireland
| | - Keyoumars Ashkan
- Neurosurgical Department, King's College Hospital Foundation Trust, London, UK.,Harley Street Clinic, London Neurosurgery Partnership, London, UK
| | - Josette Galligan
- Department of Medical Physics and Bioengineering, St. James' Hospital, Dublin, Ireland
| | - Michel Destrade
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland
| | - Niall Colgan
- Advanced Biological Imaging Laboratory, School of Physics, National University of Ireland Galway, Galway, Ireland
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Lutz NW, Bernard M. Contactless Thermometry by MRI and MRS: Advanced Methods for Thermotherapy and Biomaterials. iScience 2020; 23:101561. [PMID: 32954229 PMCID: PMC7489251 DOI: 10.1016/j.isci.2020.101561] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Control of temperature variation is of primordial importance in particular areas of biomedicine. In this context, medical treatments such as hyperthermia and cryotherapy, and also the development and use of hydrogel-based biomaterials, are of particular concern. To enable accurate temperature measurement without perturbing or even destroying the biological tissue or material to be monitored, contactless thermometry methods are preferred. Among these, the most suitable are based on magnetic resonance imaging and spectroscopy (MRI, MRS). Here, we address the latest developments in this field as well as their current and anticipated practical applications. We highlight recent progress aimed at rendering MR thermometry faster and more reproducible, versatile, and sophisticated and provide our perspective on how these new techniques broaden the range of applications in medical treatments and biomaterial development by enabling insight into finer details of thermal behavior. Thus, these methods facilitate optimization of clinical and industrial heating and cooling protocols.
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Affiliation(s)
- Norbert W. Lutz
- Aix-Marseille University, CNRS, CRMBM, 27 Bd Jean Moulin, 13005 Marseille, France
| | - Monique Bernard
- Aix-Marseille University, CNRS, CRMBM, 27 Bd Jean Moulin, 13005 Marseille, France
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Eichberg DG, Komotar RJ, Ivan ME. Commentary: Characterization of Magnetic Resonance Thermal Imaging Signal Artifact During Magnetic Resonance Guided Laser-Induced Thermal Therapy. Oper Neurosurg (Hagerstown) 2020; 19:E512-E513. [PMID: 32814960 DOI: 10.1093/ons/opaa255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 06/21/2020] [Indexed: 11/12/2022] Open
Affiliation(s)
- Daniel G Eichberg
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Ricardo J Komotar
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida.,Sylvester Comprehensive Cancer Center, Miami, Florida
| | - Michael E Ivan
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida.,Sylvester Comprehensive Cancer Center, Miami, Florida
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Munier SM, Liang AS, Desai AN, James JK, Danish SF. Characterization of Magnetic Resonance Thermal Imaging Signal Artifact During Magnetic Resonance Guided Laser-Induced Thermal Therapy. Oper Neurosurg (Hagerstown) 2020; 19:619-624. [PMID: 32735652 DOI: 10.1093/ons/opaa229] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/22/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive procedure that utilizes intraoperative magnetic resonance thermal imaging (MRTI) to generate a thermal damage estimate (TDE) of the ablative area. In select cases, the MRTI contains a signal artifact or defect that distorts the ablative region. No study has attempted to characterize this artifact. OBJECTIVE To characterize MRTI signal the artifact in select cases to better understand its potential relevance and impact on the ablation procedure. METHODS All ablations were performed using the Visualase magnetic resonance imaging-guided laser ablation system (Medtronic). Patients were included if the MRTI contained signal artifact that distorted the ablative region during the first thermal dose delivered. Ablation artifact was quantified using MATLAB version R2018a (Mathworks Inc, Natick, Massachusetts). RESULTS A total of 116 patients undergoing MRgLITT for various surgical indications were examined. MRTI artifact was observed in 37.0% of cases overall. Incidence of artifact was greater at higher powers (P < .001) and with longer ablation times (P = .024), though artifact size did not correlate with laser power or ablation duration. CONCLUSION MRTI signal artifact is common during LITT. Higher powers and longer ablation times result in greater incidence of ablation artifact, though artifact size is not correlated with power or duration. Future studies should aim to evaluate effects of artifact on postoperative imaging and, most notably, patient outcomes.
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Affiliation(s)
- Sean M Munier
- Department of Neurosurgery, Rutgers-RWJ Medical School, New Brunswick, New Jersey
| | - Allison S Liang
- Department of Neurosurgery, Rutgers-RWJ Medical School, New Brunswick, New Jersey
| | - Akshay N Desai
- Department of Neurosurgery, Rutgers-RWJ Medical School, New Brunswick, New Jersey
| | - Jose K James
- Department of Neurosurgery, Rutgers-RWJ Medical School, New Brunswick, New Jersey
| | - Shabbar F Danish
- Department of Neurosurgery, Rutgers-RWJ Medical School, New Brunswick, New Jersey
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