Model Predictive Filtering MR Temperature Imaging for Laser-Induced Interstitial Thermotherapy.

Develop a treatment planning framework for neurosurgeons treating high-grade gliomas with LITT to minimize the learning curve and improve tumor thermal dose coverage. Deidentified patient images were segmented using the image segmentation software Materialize MIMICS©. Segmented images were imported into the commercial finite element analysis (FEA) software COMSOL Multiphysics© to perform bioheat transfer simulations. The laser probe was modeled as a cylindrical object with radius 0.7 mm and length 100 mm, with a constant beam diameter. A modeled laser probe was placed in the tumor in accordance with patient specific patient magnetic resonance temperature imaging (MRTi) data. The laser energy was modeled as a deposited beam heat source in the FEA software. Penne's bioheat equation was used to model heat transfer in brain tissue. The cerebrospinal fluid (CSF) was modeled as a solid with convectively enhanced conductivity to capture heat sink effects. In this study, thermal damage-dependent blood perfusion was assessed. Pulsed laser heating was modeled based on patient treatment logs. The stationary heat source and pullback heat source techniques were modeled to compare the calculated tissue damage. The developed bioheat transfer model was compared to MRTi data obtained from a laser log during LITT procedures. The application builder module in COMSOL Multiphysics© was utilized to create a Graphical User Interface (GUI) for the treatment planning framework. Simulations predicted increased thermal damage (10-15%) in the tumor for the pullback heat source approach compared with the stationary heat source. The model-predicted temperature profiles followed trends similar to those of the MRTi data. Simulations predicted partial tissue ablation in tumors proximal to the CSF ventricle. A mobile platform-based GUI for bioheat transfer simulation was developed to aid neurosurgeons in conveniently varying the simulation parameters according to a patient-specific treatment plan. The convective effects of the CSF should be modeled with heat sink effects for accurate LITT treatment planning.

Laser interstitial thermal therapy (LITT) is popular for treating brain tumours and epilepsy. The strict control of tissue thermal damage extent is crucial for LITT. Temperature prediction is useful for predicting thermal damage extent. Accurately predicting in vivo brain tissue temperature is challenging due to the temperature dependence and the individual variations in tissue properties. Considering these factors is essential for improving the temperature prediction accuracy. Objective. To present a method for predicting patient-specific tissue temperature distribution within a target lesion area in the brain during LITT. Approach. A magnetic resonance temperature imaging (MRTI) data-driven estimation model was constructed and combined with a modified Pennes bioheat transfer equation (PBHE) to predict patient-specific temperature distribution. In the PBHE for temperature prediction, the individual specificity and temperature dependence of thermal tissue properties and blood perfusion, as well as the individual specificity of optical tissue properties were considered. Only MRTI data during one laser irradiation were required in the method. This enables the prediction of patient-specific temperature distribution and the resulting thermal damage region for subsequent ablations. Main results. Patient-specific temperature prediction was evaluated based on clinical data acquired during LITT in the brain, using intraoperative MRTI data as the reference standard. Our method significantly improved the prediction performance of temperature distribution and thermal damage region. The average root mean square error was decreased by 69.54%, the average intraclass correlation coefficient was increased by 37.5%, the average Dice similarity coefficient was increased by 43.14% for thermal damage region prediction. Significance. The proposed method can predict temperature distribution and thermal damage region at an individual patient level during LITT, providing a promising approach to assist in patient-specific treatment planning for LITT in the brain.

To develop, test and evaluate improved 2D and 3D protocols for proton resonance frequency shift magnetic resonance temperature imaging (MRTI) of laser interstitial thermal therapy (LITT). The objective was to develop improved MRTI protocols in terms of temperature measurement precision and volume coverage compared to the 2D MRTI protocol currently used with a commercially available LITT system. Four different 2D protocols and four different 3D protocols were investigated. The 2D protocols used multi-echo readouts to prolong the total MR sampling time and hence the MRTI precision, without prolonging the total acquisition time. The 3D protocols provided volumetric thermometry by acquiring a slab of 12 contiguous slices in the same acquisition time as the 2D protocols. The study only considered readily available pulse sequences (Cartesian 2D and 3D gradient recalled echo and echo planar imaging [EPI]) and methods (partial Fourier and parallel imaging) to ensure wide availability and rapid clinical implementation across vendors and field strengths. In vivo volunteer studies were performed to investigate and compare MRTI precision and image quality. Phantom experiments with LITT heating were performed to investigate and compare MRTI precision and accuracy. Different coil setups were used in the in vivo studies to assess precision differences between using local (such as flex and head coils) and non-local (i.e., body coil) receive coils. Studies were performed at both 1.5 T and 3 T. The improved 2D protocols provide up to a factor of two improvement in the MRTI precision in the same acquisition time, compared to the currently used clinical protocol. The 3D echo planar imaging protocols provide comparable precision as the currently used 2D clinical protocol, but over a substantially larger field of view, without increasing the acquisition time. As expected, local receive coils perform substantially better than the body coil, and 3 T provides better MRTI accuracy and precision than 1.5 T. 3D data can be zero-filled interpolated in all three dimensions (as opposed to just two dimensions for 2D data), reducing partial volume effects and measuring higher maximum temperature rises. With the presented protocols substantially improved MRTI precision (for 2D imaging) or greatly improved field of view coverage (for 3D imaging) can be achieved in the same acquisition time as the currently used protocol. Only widely available pulse sequences and acquisition methods were investigated, which should ensure quick translation to the clinic. Lasers Surg. Med. 51:286-300, 2019. © 2019 Wiley Periodicals, Inc.

Subependymal giant cell astrocytomas (SEGAs) are WHO grade 1 tumors associated with tuberous sclerosis that classically arise from the ventricular wall near the caudate groove and foramen of Monro. Laser interstitial thermal therapy (LITT) is a minimally invasive surgical technique, which works by heating a stereotactically placed laser fiber to ablative temperatures under MRI thermometry monitoring. In this paper, the authors present LITT as a surgical alternative to open resection of SEGAs. Twelve patients with SEGAs who underwent 16 procedures between 2007 and 2022 at a single institution were retrospectively reviewed. These patients underwent either open resection or LITT. Clinical data, imaging, recurrence rate, further treatments, and related complications were analyzed. Among the 16 procedures, 9 were open resection and 7 were LITT. An external ventricular drain was placed in 66% (6/9) of open procedures and 57.1% (4/7) of LITT cases. A septostomy was performed in 56% (5/9) of open procedures and 29% (2/7) of LITT cases. Complication rates were higher in open cases than in LITT procedures (44% vs 0%, p < 0.05). Complications included hydrocephalus, transient venous ischemia, wound infection, and bone flap migration. The median length of hospital stay was 4 days (IQR 3.3-5.5 days) for open cases and 4 days (IQR 3.0-7.0 days) for LITT procedures. Recurrence or progression occurred after 3 open cases and 2 LITT cases (33% vs 33%, p = 0.803). For the recurrences, 2 open cases underwent stereotactic radiosurgery, 1 open case underwent LITT, and 1 LITT case underwent repeat LITT. Among the LITT cases, only the patients with no decrease in tumor size by 6 months experienced tumor progression afterward. The 2 LITT cases with progression were the only ones with calcification present on preoperative imaging. The median follow-up times for cases assessed for progression were 8.4 years (IQR 3.8-14.4 years) for open resection and 3.9 years (IQR 3.4-5.1 years) for LITT. The small size of this case series limits generalizability or adequate comparison of safety. However, this series adds to the literature supporting LITT as a less invasive surgical alternative to open resection of SEGAs and demonstrates that LITT has similar recurrence and/or progression rates to open resection. Additional studies with more data are necessary for comprehensive comparisons between open resection and LITT for treating SEGA.

IntroductionThe recent emergence of laser interstitial thermal therapy (LITT) as a frontline surgical tool in the management of brain tumors and epilepsy is a result of advances in MRI thermal imaging. A limitation to further improving LITT is the diversity of brain tissue thermoablative properties, which hinders our ability to predict LITT treatment-related effects. Utilizing the mesiotemporal lobe as a consistent anatomic model system, the goal of this study was to use intraoperative thermal damage estimate (TDE) maps to study short- and long-term effects of LITT and to identify preoperative variables that could be helpful in predicting tissue responses to thermal energy.MethodsFor 30 patients with mesiotemporal epilepsy treated with LITT at a single institution, intraoperative TDE maps and pre-, intra- and post-operative MRIs were co-registered in a common reference space using a deformable atlas. The spatial overlap of TDE maps with manually-traced immediate (post-ablation) and delayed (6-month) ablation zones was measured using the dice similarity coefficient (DSC). Then, motivated by simple heat-transfer models, ablation dynamics were quantified at amygdala and hippocampal head from TDE pixel time series fit by first order linear dynamics, permitting analysis of the thermal time constant (τ). The relationships of these measures to 16 independent variables derived from patient demographics, mesiotemporal anatomy, preoperative imaging characteristics and the surgical procedure were examined.ResultsTDE maps closely overlapped immediate ablation borders but were significantly larger than the ablation cavities seen on delayed imaging, particularly at the amygdala and hippocampal head. The TDEs more accurately predicted delayed LITT effects in patients with smaller perihippocampal CSF spaces. Analyses of ablation dynamics from intraoperative TDE videos showed variable patterns of lesion progression after laser activation. Ablations tended to be slower for targets with increased preoperative T2 MRI signal and in close proximity to large, surrounding CSF spaces. In addition, greater laser energy was required to ablate mesial versus lateral mesiotemporal structures, an effect associated with laser trajectory and target contrast-enhanced T1 MRI signal.ConclusionsPatient-specific variations in mesiotemporal anatomy and pathology may influence the thermal coagulation of these tissues. We speculate that by incorporating demographic and imaging data into predictive models we may eventually enhance the accuracy and precision with which LITT is delivered, improving outcomes and accelerating adoption of this novel tool.

INTRODUCTION: Immune checkpoint blockade (ICB) has gained acceptance as a life-extending therapy in a variety of solid tumor types. For patients with brain metastases, combination stereotactic radiosurgery (SRS) and ICB remains an area of clinical equipoise. Similarly, for recurrent or difficult-to-access intracranial lesions, safety and synergy of laser interstitial thermal therapy (LITT) and ICB has yet to be explored. METHODS: In accordance with an IRB-approved protocol, all patients undergoing LITT at a tertiary center from 2015-2022 were retrospectively reviewed. Patients who received ICB within 6 weeks of LITT were included in the LITT + ICB cohort. Demographic, clinical, and survival data were collected. RESULTS: Combination LITT and ICB occurred in 25 patients with clinically recurrent tumors. The median cohort age was 62 (40-78) and 12 (48%) were female. The median KPS was 80 (50-100). The most common primary pathology was non-small cell lung cancer (NSCLC) in 15 patients (60%), followed by melanoma in 3 (12%); two high-grade gliomas were additionally treated. The majority of the cohort (24 patients, 96%) recieved single agent ICB in combination with LITT, with pembrolizumab (12, 48%) and nivolumab (6, 24%) most common. Median duration between ICB dosing and LITT was 2.85 (0.85-5.84) weeks. Ten patients (40%) had evidence of immune-related adverse events attributable to ICB, with only 1 event &gt; grade 3 according to Common Terminology Criteria; 17 (68%) had a pre-LITT steroid requirement. Intracranial adverse events related to LITT were rare, with median overall survival for the cohort of 8.6 months (1.4-26.4 months). CONCLUSIONS: Combination LITT and ICB appears safe and feasible. No prospective studies have compared cytoreduction with LITT to LITT + ICB; construction of a matched NSCLC cohort is ongoing. Exploration of the immune consequences of LITT + ICB is needed.

Background Laser interstitial thermal therapy (LITT) is a minimally invasive surgical treatment being employed frequently for radiographically progressive brain metastases. Considerable interest exists in combining LITT-mediated in situ vaccination to license immune checkpoint blockade (ICB). No studies have examined the clinical feasibility of this combination in brain metastases. Methods All patients receiving LITT for radiographically progressive non-small cell lung carcinoma (NSCLC) brain metastases at a single center from 2015 – 2023 were retrospectively reviewed. Combination therapy was defined as ICB within 6 weeks of LITT. Clinical data, post-LITT freedom from local progression (FFLP), and overall survival (OS) were collected. Adverse events (AEs) were evaluated according to Common Terminology Criteria. Results Eighteen patients received LITT + ICB to a total of 19 lesions. Median time between therapies was 2.29 weeks (range 0.85 – 5.98). In comparison to NSCLC patients receiving LITT alone or with targeted therapy (LITT only) (n = 25), there was no decrement in procedural outcomes. Patients receiving LITT + ICB discontinued steroids at a median of 11 (4 – 147) days post-LITT vs. 24 (3 – 242) days for patients receiving LITT only (P = 0.62). At study cutoff, the local control rate was 18/19 (94.7%) lesions in the LITT + ICB group and 22/25 (88.0%) in the LITT only group. There were 3 and 5 AEs ≥ Grade 3 in the LITT + ICB and LITT only group, respectively. Conclusions Combination LITT and ICB does not compromise procedural outcomes or time to steroid discontinuation in NSCLC. Prospective studies are needed to assess biomarkers of immune response.

BACKGROUND Laser interstitial thermal therapy (LITT) is a minimally invasive surgical treatment being employed frequently for radiographically progressive brain metastases (BM). Considerable interest exists in combining LITT-mediated in situ vaccination to license immune checkpoint blockade (ICB) and activate an anti-tumor immune response. However, LITT also disrupts the blood-brain barrier, causing transient peritumoral edema. Accordingly, information on safety and feasibility of this combination in BM is needed. METHODS All patients receiving LITT for radiographically progressive non-small cell lung carcinoma (NSCLC) BM at a single center from 2015 – 2023 were retrospectively reviewed. Combination therapy was defined as ICB within 6 weeks of LITT. Clinical data, post-LITT freedom from local progression (FFLP), and overall survival (OS) were collected. Adverse events (AEs) were evaluated according to Common Terminology Criteria. RESULTS Eighteen patients received LITT + ICB to a total of 19 lesions. Median time between therapies was 2.29 weeks (range 0.85 – 5.98). In comparison to NSCLC patients receiving LITT alone (n = 25), there was no decrement in % ablation (98 vs 95%, P = 0.1), length of stay (1 vs 1 days, P = 0.91), home discharge (100 vs 92%, P = 0.5), or 30-day readmissions (15.8 vs 16%, P = 0.99). Despite decreased preoperative steroid use (P = 0.0098), patients receiving LITT + ICB discontinued steroids at a median of 11 (4 – 147) days post-LITT vs. 24 (3 – 242) days for patients receiving LITT alone (P = 0.62). At study cutoff, 18/19 (94.7%) lesions in the LITT + ICB group and 22/25 (88.0%) in the LITT only group were locally controlled. There were 3 and 5 AEs ≥ Grade 3 in the LITT + ICB and LITT alone group, respectively. CONCLUSIONS Combination LITT and ICB does not compromise procedural outcomes and may favorably impact local control in NSCLC. Prospective studies are needed to assess biomarkers of immune response.

Objective.Accurate prediction of thermal damage extent is essential for effective and precise thermal therapy, especially in brain laser interstitial thermal therapy (LITT). Immediate postoperative contrast-enhanced T1-weighted imaging (CE-T1WI) is the primary method for clinically assessingin vivothermal damage after image-guided LITT. CE-T1WI reveals a hyperintense enhancing rim surrounding the target lesion, which serves as a key radiological marker for evaluating the thermal damage extent. Although widely used in clinical practice, traditional thermal damage models rely on empirical parameters fromin vitroexperiments, which can lead to inaccurate predictions of thermal damagein vivo. Additionally, these models predict only two tissue states (damaged or undamaged), failing to capture three tissue states observed on post-CE-T1WI images, highlighting the need for improved thermal damage prediction methods.Approach.This study proposes a novel convolutional long short-term memory-based model that utilizes intraoperative temperature distribution history data measured by magnetic resonance temperature imaging (MRTI) during LITT to predict the enhancing rim on post-CE-T1WI images. This method was implemented and evaluated on retrospective data from 56 patients underwent brain LITT.Main results.The proposed model effectively predicts the enhancing rim on postoperative images, achieving an average dice similarity coefficient of 0.82 (±0.063) on the test dataset. Furthermore, it generates real-time predicted thermal damage area variation trends that closely resemble those of the traditional thermal damage model, suggesting potential for real-time prediction of thermal damage extent.Significance.This method could provide a valuable tool for visualizing and assessing intraoperative thermal damage extent.

Radiation necrosis (RN) after stereotactic radiosurgery (SRS) for brain metastases (BM) can result in significant morbidity, compounded by the effects of extended steroid therapy. Laser interstitial thermal therapy (LITT) is a minimally invasive procedure that can offer definitive treatment for RN while potentially obviating the need for prolonged steroid use. To compare LITT vs medical management (MM) in the treatment of RN. A multicenter, retrospective study was performed of SRS-treated patients with BM who developed biopsy-proven RN and were treated with LITT or MM. Clinical outcome data were compared by treatment modality. Seventy-two patients met criteria with a median follow-up of 10.0 months (4.2-25.1), and 57 patients (79%) underwent LITT. Four MM (27%) and 3 LITT patients (5%) demonstrated radiographic progression (P = .031) at a median of 5.3 and 4.0 months (P = .40). There was no significant difference in overall survival (LITT median of 15.2 vs 11.6 months, P = .60) or freedom from local progression (13.6 vs 7.06 months, P = .40). Patients stopped steroid therapy earlier in the LITT cohort at a median of 37 days compared with 245 days (P < .001). When controlled for follow-up duration, patients treated with LITT were 3 times more likely to be weaned off steroids before the study end point (P = .003). These data suggest that LITT for treatment of biopsy-proven RN after SRS for BM significantly decreases time to steroid independence. Prospective trials should be designed to further validate the utility of LITT for RN and its impact on steroid-induced morbidity.

INTRODUCTION Laser Interstitial Thermal Therapy (LITT) is a minimally invasive modality that employs controlled hyperthermia to ablate tumor tissue while transiently disrupting the blood-brain barrier. In a recent phase II trial, low dose doxorubicin infusions following LITT improved survival compared to LITT alone; however, the clinical benefit remains compromised by the systemic toxicities inherent to doxorubicin. Here we utilize LITT and Thermodox, a heat-sensitive liposomal formulation encapsulating doxorubicin, to deliver targeted chemotherapy to the brain. At normal body temperatures, the liposome retains doxorubicin, while above 41.5°C during LITT, it rapidly releases high local doses, thus minimizing systemic exposure. METHODS Using a commercial LITT system, laser fibers were inserted in bilateral frontal lobes of healthy Yucatan mini pigs under image guidance. One hemisphere received LITT alone, while the contralateral side underwent LITT concurrent with Thermodox infusion (50 mg/m2). Animals were sacrificed immediately or at 7 days to assess intraparenchymal drug release and delayed neurotoxicity. Doxorubicin release was evaluated via fluorometric imaging, and histological analysis assessed tissue damage. RESULTS Immediate fluorometric assays demonstrated targeted intraparenchymal doxorubicin release surrounding the zone of ablation in the hemisphere that received LITT + Thermodox. There were no clinical signs of systemic or neurotoxicity during the 7-day monitoring period. No additional cerebral edema was noted on surveillance imaging in the hemisphere that received LITT + Thermodox compared to the hemisphere with LITT alone. DISCUSSION Our findings demonstrate that LITT-mediated, heat-triggered release of doxorubicin from Thermodox enables safe, targeted CNS drug delivery, overcoming the poor CNS penetration and systemic toxicity of conventional doxorubicin. These promising results, together with the established systemic safety of Thermodox in non-CNS trials, support rapid clinical translation. Future studies will refine thermal dosing to maximize drug release using both ablative and sub-ablative temperatures.

INTRODUCTION Treatment of intracranial lesions with laser interstitial thermal therapy (LITT) allows for simultaneous cytoreduction and the potential to generate an anti-tumor immune response. The safety and efficacy of combination immune checkpoint blockade (ICB) and LITT has not been determined. METHODS All patients who received LITT for neuro-oncologic indications at a single NCI-designated cancer center from 2015 – 2022 were included. Simultaneous ICB was defined as receipt of therapy within 6 weeks of LITT. Demographic, clinical, and survival data were collected. Immune-related and intracranial adverse events (iRAEs and IAEs) were graded according to Common Terminology Criteria. RESULTS Twenty-four patients received simultaneous LITT and ICB. Median age was 62 (range 40 - 78) and 12 (48%) were female. Median KPS was 80 (50 – 100). Use of ICB increased during the study period (r = 0.69). The most common pathology was non-small cell lung cancer (15 patients, 62.5%), followed by melanoma in 3 (12.5%) and 2 (8.3%) patients each with renal cell carcinoma or high-grade glioma. Twenty-three (96%) patients received single agent ICB, with pembrolizumab most common (12, 50%), followed by nivolumab (6, 25%). The median interval between LITT and ICB was 2.56 (0.85 – 4.98) weeks. The most common iRAE was hypothyroidism in 4 (16.6%) patients, with grade 3 pneumonitis in one patient. The most common IAE was seizures in 4 (16.6%) patients. Local progression was seen in 4 patients (16.6%), with a post-LITT overall survival of 20.6 (1.0 – 36.1) months for the cohort. CONCLUSIONS Combination LITT and ICB appears safe and effective, with iRAEs commensurate with trials of checkpoint inhibition. High-grade intracranial toxicity was rare. Prospective studies of combinatorial LITT + ICB are needed to establish biomarkers and optimal timing.

Malignant gliomas are devastating intracranial tumors with dismal prognoses that impose unique therapeutic challenges. Treatment options include surgical resection, radiation, and chemotherapy, but efficacy is limited and carries associated morbidity. Promise persists for newer modalities, such as immune-based platforms, but obstacles include limited therapeutic access due to the blood-brain barrier (BBB) and the highly immunosuppressive tumor microenvironment. Laser interstitial thermal therapy (LITT) is a minimally invasive surgical intervention permitting thermal ablation of intracranial tumors. During LITT, a laser probe is stereotactically placed in the lesion through a skull burr hole. Real-time MRI is used to calculate thermal dosage zones to monitor ablation progress. LITT is not only cytoreductive but also opens the BBB and induces a powerful hyperthermia-driven anti-tumor immune response; it thus may synergize with other emerging therapies. Spontaneous canine glioma offers a matchless, optimally recapitulative appropriately sized tumor model, providing a unique opportunity to investigate and optimize the LITT platform. We adapted a commercially available LITT system (Monteris Medical) for application in canines with intracranial lesions. Initially, canine cadavers were used to optimize LITT procedures; we then performed LITT in live dogs. Our approach consists of 1. obtaining volumetric MRI studies for trajectory planning, 2. fixing canine patients to the surgical bed, 3. registering anatomic landmarks (Brainlab) to a volume rendered image, 4. using an integrated instrument holder (Varioguide, Brainlab) to guide drilling of 4.5 mm skull burr holes for placement of self-tapping titanium “mini-bolts” (Monteris Medical), and 5. introducing the laser through the mini-bolts for ablation in the MRI suite. This method allows for rigid stereotaxy, successful neuronavigation, and a minimally invasive approach. We have successfully performed LITT on four canine patients with intracranial gliomas. Future studies will explore immunologic mechanisms underlying the post-LITT anti-tumor response as well as combination therapeutic platforms, including nanoparticles and stereotactic radiotherapy.

Brain metastasis (BM) affects up to one-third of adults with cancer and carries a historically bleak prognosis. Despite advances in stereotactic radiosurgery (SRS), rates of in-field recurrence (IFR) after SRS range from 10 to 25%. High rates of neurologic death have been reported after SRS failure, particularly for recurrences deep in the brain and surgically inaccessible. Laser interstitial thermal therapy (LITT) is an emerging option in this setting, but its ability to prevent a neurologic death is unknown. In this study, we investigate the causes of death among patients with BM who undergo LITT for IFR after SRS. We conducted asingle institution retrospective case series of patients with BM who underwent LITT for IFR after SRS. Clinical and demographic data were collected via chart review. The primary endpoint was cause of death. Between 2010 and 2018, 70 patients with BM underwent LITT for IFR after SRS. Median follow-up after LITT was 12.0months. At analysis, 49 patients died; a cause was determined in 44. Death was neurologic in 20 patients and non-neurologic in 24. The 24-month cumulative incidence of neurologic and non-neurologic death was 35.1% and 38.6%, respectively. Etiologies of neurologic death included local recurrence (n = 7), recovery failure (n = 7), distant progression (n = 5), and other (n = 1). Among our patient population, LITT provided the ability to stabilize neurologic disease in up to 2/3 of patients. For IFR after SRS, LITT may represent a reasonable treatment strategy for select patients. Additional work is necessary to determine the extent to which LITT can prevent neurologic death after recurrence of BM.

BACKGROUND:Surgical treatments for deep-seated intracranial lesions have been limited by morbidities associated with resection. Real-time magnetic resonance imaging–guided focused laser interstitial thermal therapy (LITT) offers a minimally invasive surgical treatment option for such lesions.OBJECTIVE:To review treatments and results of patients treated with LITT for intracranial lesions at Washington University School of Medicine.METHODS:In a review of 17 prospectively recruited LITT patients (34-78 years of age; mean, 59 years), we report demographics, treatment details, postoperative imaging characteristics, and peri- and postoperative clinical courses.RESULTS:Targets included 11 gliomas, 5 brain metastases, and 1 epilepsy focus. Lesions were lobar (n = 8), thalamic/basal ganglia (n = 5), insular (n = 3), and corpus callosum (n = 1). Mean target volume was 11.6 cm3, and LITT produced 93% target ablation. Patients with superficial lesions had shorter intensive care unit stays. Ten patients experienced no perioperative morbidities. Morbidities included transient aphasia, hemiparesis, hyponatremia, deep venous thrombosis, and fatal meningitis. Postoperative magnetic resonance imaging showed blood products within the lesion surrounded by new thin uniform rim of contrast enhancement and diffusion restriction. In conjunction with other therapies, LITT targets often showed stable or reduced local disease. Epilepsy focus LITT produced seizure freedom at 8 months. Preliminary overall median progression-free survival and survival from LITT in tumor patients were 7.6 and 10.9 months, respectively. However, this small cohort has not been followed for a sufficient length of time, necessitating future outcomes studies.CONCLUSION:Early peri- and postoperative clinical data demonstrate that LITT is a safe and viable ablative treatment option for intracranial lesions, and may be considered for select patients.ABBREVIATION:LITT, laser interstitial thermal therapy