ablation volume
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2021 ◽  
pp. 1-7
Author(s):  
Brian Y. Hwang ◽  
Alexander Eremiev ◽  
Adhith Palla ◽  
David Mampre ◽  
Serban Negoita ◽  
...  

OBJECTIVE Maximal safe ablation of target structures during magnetic resonance–guided laser interstitial thermal therapy (MRgLiTT) is critical to achieving good seizure outcome in patients with mesial temporal lobe epilepsy (mTLE). The authors sought to determine whether intraoperative physiological variables are associated with ablation volume during MRgLiTT. METHODS Patients with mTLE who underwent MRgLiTT at our institution from 2014 to 2019 were retrospectively analyzed. Ablation volume was determined with volumetric analysis of intraoperative postablation MR images. Physiological parameters (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP], end-tidal carbon dioxide [ETCO2]) measured 40 minutes prior to ablation were analyzed. Univariate and multivariate regression analyses were performed to determine independent predictors of ablation volume. RESULTS Forty-four patients met the inclusion criteria. The median (interquartile range) ablation volume was 4.27 (2.92–5.89) cm3, and median ablation energy was 7216 (6402–8784) J. The median MAP, SBP, DBP, and ETCO2 values measured during the 40-minute period leading up to ablation were 72.8 (66.2–81.5) mm Hg, 104.4 (96.4–114.4) mm Hg, 62.4 (54.1–69.8) mm Hg, and 34.1 (32.0–36.2) mm Hg, respectively. In univariate analysis, only total laser energy (r = 0.464, p = 0.003) and 40-minute average ETCO2 (r = −0.388, p = 0.012) were significantly associated with ablation volume. In multivariate analysis, only ETCO2 ≤ 33 mm Hg (p = 0.001) was significantly associated with ablation volume. CONCLUSIONS Total ablation energy and ETCO2, but not blood pressure, may significantly affect ablation volume in mTLE patients undergoing MRgLiTT. Mild hypocapnia was associated with increased extent of ablation. Intraoperative monitoring and modulation of ETCO2 may help improve extent of ablation, prediction of ablation volume, and potentially seizure outcome.


2021 ◽  
pp. jnnp-2021-327730
Author(s):  
David Satzer ◽  
Anil Mahavadi ◽  
Maureen Lacy ◽  
Jon E Grant ◽  
Peter Warnke

BackgroundAnterior capsulotomy is a well-established treatment for refractory obsessive–compulsive disorder (OCD). MRI-guided laser interstitial thermal therapy (LITT) allows creation of large, sharply demarcated lesions with the safeguard of real-time imaging.ObjectiveTo characterise the outcomes of laser anterior capsulotomy, including radiographical predictors of improvement.MethodsPatients with severe OCD refractory to pharmacotherapy and cognitive–behavioural therapy underwent bilateral anterior capsulotomy via LITT. The primary outcome was per cent reduction in Yale-Brown Obsessive–Compulsive Scale (Y-BOCS) score over time. Lesion size was measured on postablation MRI. Disconnection of the anterior limb of the internal capsule (ALIC) was assessed via individual and normative tractography.ResultsEighteen patients underwent laser anterior capsulotomy. Median follow-up was 6 months (range 3–51 months). Time occupied by obsessions improved immediately (median Y-BOCS item 1 score 4–1, p=0.002). Mean (±SD) decrease in Y-BOCS score at last follow-up was 46%±32% (16±11 points, p<0.0001). Sixty-one per cent of patients were responders. Seven patients (39%) exhibited transient postoperative apathy. One patient had an asymptomatic intracerebral haemorrhage. Reduction in Y-BOCS score was positively associated with ablation volume (p=0.006). Individual tractography demonstrated durable ALIC disconnection. Normative tractography revealed a dorsal–ventral gradient, with disconnection of orbitofrontal streamlines most strongly associated with a positive response (p<0.0001).ConclusionsLaser anterior capsulotomy resulted in immediate, marked improvement in OCD symptom severity. Larger lesions permit greater disconnection of prefrontal–subcortical pathways involved in OCD. The importance of greater disconnection is presumably related to variation in ALIC structure and the complex role of the PFC in OCD.


2021 ◽  
Vol 22 (19) ◽  
pp. 10833
Author(s):  
Jan Hahn ◽  
Manuela Moritz ◽  
Hannah Voß ◽  
Penelope Pelczar ◽  
Samuel Huber ◽  
...  

It was recently shown that ultrashort pulse infrared (IR) lasers, operating at the wavelength of the OH vibration stretching band of water, are highly efficient for sampling and homogenizing biological tissue. In this study we utilized a tunable nanosecond infrared laser (NIRL) for tissue sampling and homogenization with subsequent liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis for mass spectrometric proteomics. For the first time, laser sampling was performed with murine spleen and colon tissue. An ablation volume of 1.1 × 1.1 × 0.4 mm³ (approximately 0.5 µL) was determined with optical coherence tomography (OCT). The results of bottom-up proteomics revealed proteins with significant abundance differences for both tissue types, which are in accordance with the corresponding data of the Human Protein Atlas. The results demonstrate that tissue sampling and homogenization of small tissue volumes less than 1 µL for subsequent mass spectrometric proteomics is feasible with a NIRL.


2021 ◽  
Author(s):  
Evan Luther ◽  
Victor M Lu ◽  
Alexis A Morell ◽  
Turki Elarjani ◽  
Samuel Mansour ◽  
...  

Abstract BACKGROUND Laser interstitial thermal therapy (LITT) for posterior fossa lesions remains rare as the small size of the infratentorial compartment, proximity to the brainstem, and thickness/angulation of the occipital bone creates barriers to procedural success. Furthermore, evaluation of the effect of ablation volume on outcomes is limited. OBJECTIVE To analyze our institutional experience with LITT in the posterior fossa stratifying perioperative and long-term outcomes by ablation volumes. METHODS Seventeen patients with posterior fossa lesions treated with LITT from 2013 to 2020 were identified. Local progression-free survival (PFS), overall survival, steroid dependence, and edema reduction were evaluated with Kaplan-Meier analysis grouped by ablation volume. Preoperative, postoperative, and last known Karnofsky Performance Status (KPS) were compared using a matched paired t test. RESULTS No differences in pathology, preoperative KPS, or preoperative lesion volume were found between patients with total (100%-200% increase in pre-LITT lesion volume) versus radical (&gt;200% increase in pre-LITT lesion volume) ablations. Patients who underwent radical ablation had a higher postoperative KPS (93 vs 82, P = .02) and higher KPS (94 vs 87, P = .04) and greater reduction in perilesional edema at last follow-up (P = .01). Median follow-up was 80.8 wk. CONCLUSION Despite obvious anatomical challenges, our results demonstrate that radical ablations are both feasible and safe in the posterior fossa. Furthermore, radical ablations may lead to greater decreases in perilesional edema and improved functional status both immediately after surgery and at last follow-up. Thus, LITT should be considered for patients with otherwise unresectable or radioresistant posterior fossa lesions.


Author(s):  
Chin-Jung Wang ◽  
Gigin Lin ◽  
Yi-Ting Huang ◽  
Cindy Hsuan Weng ◽  
Kai-Yun Wu ◽  
...  

Abstract Purpose Uterine fibroids are benign gynecologic tumors and commonly occur in women by the age of 50. Women with symptomatic uterine fibroids generally receive surgical intervention, while they do not favor the invasive therapies. To evaluate the feasibility and safety of a novel magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) modality, ArcBlate, in the treatment of uterine fibroids. Methods Nine patients with uterine fibroids and one patient with adenomyosis were treated with ArcBlate MRgHIFU. Tumor size and quality of life were evaluated postoperatively at 1 and 3 months by magnetic resonance imaging (MRI) and the 36-Item Short Form Survey (SF-36), respectively. Results All patients completed the ArcBlate MRgHIFU procedure and there were no treatment-related adverse effects either during the procedure or during the 3 months of follow-up. Despite limiting the ablation volume to under 50% of the treated fibroid volume as a safety precaution, tumor volumes were markedly reduced in four patients by 15.78–58.87% at 3-month post-treatment. Moreover, SF-36 scale scores had improved at 3 months from baseline by 2–8 points in six patients, indicating relief of symptoms and improved quality of life. Conclusion This study evidence demonstrates the safety and feasibility of ArcBlate MRgHIFU and suggests its potential for treating uterine fibroids.


2021 ◽  
Vol 13 (13) ◽  
pp. 7196
Author(s):  
Ruoshen Lin ◽  
Gang Mei ◽  
Ziyang Liu ◽  
Ning Xi ◽  
Xiaona Zhang

Glacier debris flow is one of the most critical categories of geological hazards in high-mountain regions. To reduce its potential negative effects, it needs to investigate the susceptibility of glacier debris flow. However, when evaluating the susceptibility of glacier debris flow, most research work considered the impact of existing glacier area, while ignoring the impact of changes in glacier ablation volume. In this paper, we considered the impact of the changes in the glacier ablation volume to investigate the susceptibility of glacier debris flow. We proposed to evaluate the susceptibility analysis in G217 gullies with frequent glacial debris flow on the Duku highway, Xinjiang Province. Specifically, by using the simple band ratio method with the manual correction to identify glacier outlines, we identified the ablation zone by comparing the glacier boundary in 2000 with that in 2015. We then calculated ablation volume by changes in glacier elevation and ablation area from 2000 to 2015. Finally, we used the volume of glacier melting in different watersheds as the main factor to evaluate the susceptibility based on the improved geomorphic information entropy (GIE) method. We found that, overall, the improved GIE method with a correction coefficient based on the glacier ablation volume is better than the previous method. Deglaciation can be adapted to analyze glacier debris flow susceptibility based on glaciology and geomorphology. Our presented work can be applied to other similar glacial debris flow events in high-mountain regions.


2021 ◽  
pp. 1-10
Author(s):  
David Satzer ◽  
James X. Tao ◽  
Peter C. Warnke

OBJECTIVE The authors aimed to examine the relationship between mesial temporal subregion ablation volume and seizure outcome in a diverse cohort of patients who underwent stereotactic laser amygdalohippocampotomy (SLAH) for mesial temporal lobe epilepsy (MTLE). METHODS Seizure outcomes and pre- and postoperative images were retrospectively reviewed in patients with MTLE who underwent SLAH at a single institution. Mesial temporal subregions and the contrast-enhancing ablation volume were manually segmented. Pre- and postoperative MR images were coregistered to assess anatomical ablation. Postoperative MRI and ablation volumes were also spatially normalized, enabling the assessment of seizure outcome with heat maps. RESULTS Twenty-eight patients with MTLE underwent SLAH, 15 of whom had mesial temporal sclerosis (MTS). The rate of Engel class I outcome at 1 year after SLAH was 39% overall: 47% in patients with MTS and 31% in patients without MTS. The percentage of parahippocampal gyrus (PHG) ablated was higher in patients with an Engel class I outcome (40% vs 25%, p = 0.04). Subregion analysis revealed that extent of ablation in the parahippocampal cortex (35% vs 19%, p = 0.03) and angular bundle (64% vs 43%, p = 0.02) was positively associated with Engel class I outcome. The degree of amygdalohippocampal complex (AHC) ablated was not associated with seizure outcome (p = 0.30). CONCLUSIONS Although the AHC was the described target of SLAH, seizure outcome in this cohort was associated with degree of ablation for the PHG, not the AHC. Complete coverage of both the AHC and PHG is technically challenging, and more work is needed to optimize seizure outcome after SLAH.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3082-3082
Author(s):  
Min Yuan ◽  
Qing Xu ◽  
Zhongzheng Zhu ◽  
Wei Mao ◽  
Xianling Guo ◽  
...  

3082 Background: Chemotherapy-induced thrombocytopenia (CIT) contributes to treatment dose delay and/or modification, often resulting in poorer survival and disease progression. Compared with partial splenic embolization (PSE) and drugs, high-intensity focused ultrasound has the advantages as following: (1) it is a noninvasive treatment modality with potentially fewer adverse effects and complications; (2) the hospital stay and recovery time after treatment are short; (3) its cost is relatively low compared to surgery. The purpose of this work was to preliminarily investigate the efficacy and safety of high intensity focused ultrasound treatment of chemotherapy-induced thrombocytopenia (CIT) and hypersplenism. Methods: 26 patients with chemotherapy-induced thrombocytopenia and hypersplenism (15 male and 11 female; median age, 56 years; range, 51-66 years) were treated with ultrasound guided high-intensity focused ultrasound. Complications were recorded. Laboratory examination and magnetic resonance imaging were used to evaluate the efficacy. The spleen volume and ablation volume rate of the spleen were calculated by MRI after treatment. They were followed closely for at least 6 months. Results: After high-intensity focused ultrasound treatment, the MRI showed that the ablation area had turned into a non-perfused volume, the mean percent spleen ablation volume was 18.76% ± 6.1% (range, 11.17%-32.34%). After 6 months of HIFU ablation, the ablated area shrank evidently; the sunken spleen formed a lobulated shape and the splenic volume decreased. The platelet count increased 3-7 days after treatment and remained for 1-2weeks higher than baseline (53.33 ± 15.80 × 109/L). The white blood cell count and platelet count of the patients were substantially improved during the follow-up period. No substantial difference was observed in RBC counts between baseline and after treatment. In addition, symptoms such as epistaxis and gingival bleeding were ameliorated or even eliminated, and the quality of life was improved. Follow-up imaging showed a nonperfused volume in the spleen. Conclusions: For the first time to our knowledge, high-intensity focused ultrasound ablation was used to treat Chemotherapy-induced thrombocytopenia (CIT) and hypersplenism. High-intensity focused ultrasound ablation of the spleen may cause damage to a certain volume of the spleen parenchyma to achieve the purpose of hypersplenism treatment. High intensity focused ultrasound may be an effective and safe alternative for treatment of CIT and hypersplenism.


2021 ◽  
Vol 11 ◽  
Author(s):  
Raluca-Maria Sandu ◽  
Iwan Paolucci ◽  
Simeon J. S. Ruiter ◽  
Raphael Sznitman ◽  
Koert P. de Jong ◽  
...  

BackgroundIn thermal ablation of liver tumors, complete coverage of the tumor volume by the ablation volume with a sufficient ablation margin is the most important factor for treatment success. Evaluation of ablation completeness is commonly performed by visual inspection in 2D and is prone to inter-reader variability. This work aimed to introduce a standardized approach for evaluation of ablation completeness after CT-guided thermal ablation of liver tumors, using volumetric quantitative ablation margins (QAM).MethodsA QAM computation metric based on volumetric segmentations of tumor and ablation areas and signed Euclidean surface distance maps was developed, including a novel algorithm to address QAM computation in subcapsular tumors. The code for QAM computation was verified in artificial examples of tumor and ablation spheres simulating varying scenarios of ablation margins. The applicability of the QAM metric was investigated in representative cases extracted from a prospective database of colorectal liver metastases (CRLM) treated with stereotactic microwave ablation (SMWA).ResultsApplicability of the proposed QAM metric was confirmed in artificial and clinical example cases. Numerical and visual options of data presentation displaying substrata of QAM distributions were proposed. For subcapsular tumors, the underestimation of tumor coverage by the ablation volume when applying an unadjusted QAM method was confirmed, supporting the benefits of using the proposed algorithm for QAM computation in these cases. The computational code for developed QAM was made publicly available, encouraging the use of a standard and objective metric in reporting ablation completeness and margins.ConclusionThe proposed volumetric approach for QAM computation including a novel algorithm to address subcapsular liver tumors enables precision and reproducibility in the assessment of ablation margins. The quantitative feedback on ablation completeness opens possibilities for intra-operative decision making and for refined analyses on predictability and consistency of local tumor control after thermal ablation of liver tumors.


Author(s):  
P. Hendriks ◽  
W. E. M. Berkhout ◽  
C. I. Kaanen ◽  
J. H. Sluijter ◽  
I. J. Visser ◽  
...  

Abstract Purpose To investigate the performance of two microwave ablation (MWA) systems regarding ablation volume, ablation shape and variability. Materials and Methods In this ex vivo study, the Emprint and Amica MWA systems were used to ablate porcine livers at 4 different settings of time and power (3 and 5 minutes at 60 and 80 Watt). In total, 48 ablations were analysed for ablation size and shape using Vitrea Advanced Visualization software after acquisition of a 7T MRI scan. Results Emprint ablations were smaller (11,1 vs. 21,1 mL p < 0.001), more spherical (sphericity index of 0.89 vs. 0.59 p < 0.001) and showed less variability than Amica ablations. In both systems, longer ablation time and higher power resulted in significantly larger ablation volumes. Conclusion Emprint ablations were more spherical, and the results showed a lower variability than those of Amica ablations. This comes at the price of smaller ablation volumes.


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