Photoacoustic-guided endovenous laser ablation: Characterization and in vivo canine study.
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ABSTRACT:
SUBMITTER: Yan Y
PROVIDER: S-EPMC8416949 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Accurate fiber tip tracking is a critical clinical problem during endovenous laser ablation (EVLA) of small perforating veins. Currently, ultrasound (US) imaging is the gold-standard modality for visualizing and for accurately placing the ablation fiber within the diseased vein. However, US imaging has limitations such as angular dependency and comet tail artifacts. In addition, EVLA is often performed without any real-time temperature monitoring, which could lead to an insufficient thermal dose or overheating the surrounding tissue. We propose a new technique that combines US and photoacoustic (PA) imaging for concurrent ablation fiber tip tracking and real-time temperature monitoring during EVLA procedures. Our intended implementation of PA imaging for fiber tracking requires minimal modification of existing systems, which makes this technology easy to adopt. Combining US and PA imaging modalities allows for simultaneous visualization of background anatomical structures as well as high contrast, artifact-free, and angle-independent localization of the ablation fiber tip. Preliminary data demonstrates that changes in the amplitude of the PA signal can be used to monitor the localized temperature at the tip of the ablation fiber, which will be invaluable during EVLA procedures. These improvements can enhance the physician's accuracy in performing EVLA procedures and will have a significant impact on the treatment outcomes.
| S-EPMC6393544 | biostudies-literature
Project description:Endovenous thermal and non-thermal therapeutic approaches have become standard of care for the treatment of venous insufficiency. However, comparative studies on its use in the population of venous leg ulcer patients are scarce. The present study aimed at a comparison of the efficacy of endovenous laser ablation (EVLA) and ultrasound-guided foam sclerotherapy (UGFS) for the treatment of venous leg ulcers (VUs). We retrospectively analyzed patient records of 68 patients with active VUs (C6 of the CEAP-classification), who underwent EVLA (n = 33) or UGFS (n = 35) between January 2001 and January 2021. In 68 patients, 97 venous segments (GSV: 43, SSV: 17, NSV: 37) were treated. Ulcer surface area at initial presentation did not differ significantly between both treatment groups (EVLA: 7.7 ± 10.7 vs. UGFS: 8.5 ± 16.3 cm2 ; p = 0.73). No significant difference regarding patient characteristics was found, with the exception of age, as patients receiving UGFS treatment were significantly older (EVLA: 61 ± 17 vs. UGFS: 70 ± 14 years; p = 0.018). The rate of ulcer resolution was not significantly different between EVLA and UGFS groups (97.0% vs. 85.7%; p = 0.20). Also, the mean time to complete ulcer healing after endovenous intervention was comparable (EVLA: 59 ± 37 vs. UGFS: 63 ± 41 days; p = 0.68). However, the relapse rate was significantly higher for UGFS than for EVLA treated patients (31.4% vs. 3.0%; p = 0.002). Taken together, rates of ulcer resolution and ulcer healing time after endovenous intervention were comparable between both treatment modalities. Nevertheless, a significantly higher relapse rate was observed in UGFS treated patients.
| S-EPMC9285388 | biostudies-literature
Project description:BackgroundEndovenous thermal techniques, such as endovenous laser ablation (EVLA), are the recommended treatment for truncal varicose veins. However, a disadvantage of thermal techniques is that it requires the administration of tumescent anaesthesia, which can be uncomfortable. Non-thermal, non-tumescent techniques, such as mechanochemical ablation (MOCA) have potential benefits. MOCA combines physical damage to endothelium using a rotating wire, with the infusion of a liquid sclerosant. Preliminary experiences with MOCA showed good results and less post-procedural pain.Methods/designThe Laser Ablation versus Mechanochemical Ablation (LAMA) trial is a single-centre randomised controlled trial in which 140 patients will be randomly allocated to EVLA or MOCA. All patients with primary truncal superficial venous insufficiency (SVI) who meet the eligibility criteria will be invited to participate in this trial. The primary outcomes are intra-procedural pain and technical efficacy at 1 year, defined as complete occlusion of target vein segment and assessed using duplex ultrasound. Secondary outcomes are post-procedural pain, analgesia use, procedure time, clinical severity, generic and disease-specific quality of life, bruising, complications, satisfaction, cosmesis, time taken to return to daily activities and/or work, and cost-effectiveness analysis following EVLA or MOCA. Both groups will be evaluated on an intention-to-treat basis.DiscussionThe aim of the LAMA trial is to establish whether MOCA is superior to the current first-line treatment, EVLA. The two main hypotheses are that MOCA may cause less initial pain and disability allowing a more acceptable treatment with an enhanced recovery. The second hypothesis is that this may come at a cost of decreased efficacy, which may lead to increased recurrence and affect longer term quality of life, increasing the requirement for secondary procedures.Trial registrationClinicalTrials.gov identifier: NCT02627846 , registered 8 December 2015 EudraCT number: 2015-000730-30 REC ref: 15/YH/0207 R&D ref: R1788.
| S-EPMC4995808 | biostudies-literature
Project description:IntroductionEndovenous microwave ablation (EMA) is a relatively novel thermal ablation treatment for great saphenous vein (GSV) varicosis, and its efficacy and safety are rarely reported. This study aims to explore whether EMA can be comparable to endovenous laser ablation (EVLA), which is a widely used thermal ablation treatment in clinical practice.Methods and analysisThis is a multicentre, randomised controlled non-inferiority trial to compare the efficacy and safety of EMA and EVLA in patients with GSV varicosis. We will recruit 180 patients in 6 centres and randomly assign them into treatment group (EMA group) and control group (EVLA group) in a 1:1 ratio. The patients will return to the hospitals at 7 days, 3 months, 6 months and 12 months, and will be called at 1 month after the treatment for follow-up visits. The primary outcome is the occlusion rate of GSV immediately, at 6 months, and at 12 months after the treatment. The secondary outcomes are Venous Clinical Severity Score (VCSS), Aberdeen Varicose Vein Questionnaire (AVVQ) Score, operation time and instrument performance evaluation.Ethics and disseminationThis protocol has been approved by the Clinical Trial Ethics Committee of Beijing Hospital (2020BJYYEC-126-02), Peking Union Medical College Hospital (KS2020393), Beijing Tsinghua Changgung Hospital (No.20279-2-02), Beijing Luhe Hospital.Capital Medical University (2020-LHYW-030-01), the First Hospital of Hebei Medical University (No.2020249), and the First Affiliated Hospital of Xi'an Jiaotong University (XJTU1AF2021LSY-12). The trial results will be published in peer-reviewed journals.Trial registration numberNCT04726124.
| S-EPMC9134177 | biostudies-literature
Project description:Prostate cancer (PCa) is the most common malignant tumor in men. Prostate-specific membrane antigen (PSMA), which is overexpressed on the surface of Prostate cancer cells, may serve as a potential therapeutic target. Recently, image-guided and targeted therapy for prostate cancers has attracted much attention by using Prostate-specific membrane antigen targeting nanoparticle. In this study, we produced PSMA-targeted light-responsive nanosystems. These nanosystems of liquid perfluorocarbon cores and polymer shells were loaded with the photosensitizer IR780 and therapeutic drugs paclitaxel. The liquid perfluorocarbon (PFP) in nanoparticles can perform ultrasound-enhanced imaging by liquid-gas transition and promote the deliver and release of paclitaxel. IR780 can perform photothermal therapy (PTT) guided by photoacoustic (PA) imaging. Combination treatment with photothermal therapy and chemotherapy exhibited excellent inhibition of cell proliferation in vitro and a significant therapeutic effect in vivo. In conclusion, we successfully formulated PSMA-targeted nanosystems with precision targeting and ultrasound/PA dual-modality imaging for anti-tumor effects.
| S-EPMC10070956 | biostudies-literature
Project description:Background and objectivesEndovenous laser treatment (ELT) has been recently proposed as an alternative in the treatment of reflux of the Great Saphenous Vein (GSV) and Small Saphenous Vein (SSV). Successful ELT depends on the selection of optimal parameters required to achieve an optimal vein damage while avoiding side effects. Mathematical modeling of ELT could provide a better understanding of the ELT process and could determine the optimal dosage as a function of vein diameter.Study design/materials and methodsThe model is based on calculations describing the light distribution using the diffusion approximation of the transport theory, the temperature rise using the bioheat equation and the laser-induced injury using the Arrhenius damage model. The geometry to simulate ELT was based on a 2D model consisting of a cylindrically symmetric blood vessel including a vessel wall and surrounded by an infinite homogenous tissue. The mathematical model was implemented using the Macsyma-Pdease2D software (Macsyma Inc., Arlington, MA, USA). Damage to the vein wall for CW and single shot energy was calculated for 3 and 5 mm vein diameters. In pulsed mode, the pullback distance (3, 5 and 7 mm) was considered. For CW mode simulation, the pullback speed (1, 2, 3 mm/s) was the variable. The total dose was expressed as joules per centimeter in order to perform comparison to results already reported in clinical studies.ResultsIn pulsed mode, for a 3 mm vein diameter, irrespective of the pullback distance (2, 5 or 7 mm), a minimum fluence of 15 J/cm is required to obtain a permanent damage of the intima. For a 5 mm vein diameter, 50 J/cm (15W-2s) is required. In continuous mode, for a 3 mm and 5 mm vein diameter, respectively 65 J/cm and 100 J/cm are required to obtain a permanent damage of the vessel wall. Finally, the use of different wavelengths (810 nm or 980 nm) played only a minor influence on these results.Discussion and conclusionThe parameters determined by mathematical modeling are in agreement with those used in clinical practice. They confirm that thermal damage of the inner vein wall (tunica intima) is required to achieve the tissue alterations necessary in order to lead the vein to permanent occlusion. However, in order to obtain a high rate of success without adverse events, the knowledge of the vein diameter after tumescent anesthesia is recommended in order to use the optimal energy. As clearly demonstrated by our calculations, both pulsed and continuous mode operations of the laser can be efficient. An interesting observation in our model is that less amount of energy is required in pulsed mode than in continuous mode. Damaging the vein sequentially along its entire length may lead to permanent occlusion. However, the pulsed mode requires a very precise positioning of the fiber after each pullback and the duration of the treatment is much longer. For these reasons, continuous irradiation seems to be preferred by most clinicians. This model should serve as a useful tool to simulate and better understand the mechanism of action of the ELT.
| S-EPMC1464132 | biostudies-literature
Project description:BackgroundRecurrent varicosities after endovascular laser ablation (EVLA) of the great saphenous vein (GSV) are frequently due to varicose transformed, initially unsealed major ascending tributaries of the saphenofemoral junction (SFJ). Preventive ablation of these veins, especially the anterior accessory saphenous vein, is discussed as an option, along with flush occlusion of the GSV. However, few related data exist to date.MethodsA consecutive case series of 278 EVLA procedures of the GSV for primary varicosis in 213 patients between May and December 2019 was retrospectively reviewed. The ablations were performed with a 1470 nm dual-ring radial laser and always included flush occlusion of the GSV, and concomitant ablation of its highest ascending tributaries by additional cannulation and ablation when this seemed anatomically appropriate. The initial technical success, comprising occlusion of the GSV and its major tributaries, was set as the primary endpoint. Possible determinants were explored using downstream multiple logistic regression analysis.ResultsThe early technical success was 92.8%, with the GSV occluded in 99.6% and the highest ascending SFJ tributary, if present, in 92.4%. Additional ablations of ascending tributaries were performed in 171 cases (61.5%), the latter being associated with success (OR 10.39; 95% CI [3.420-36.15]; p < 0.0001). Presence of anterior as opposed to posterior accessory saphenous vein was another positive predictor (OR 3.959; 95% CI [1.142-13,73]; p = 0.027), while a confluence of the tributary in the immediate proximity to the SFJ had a negative impact (OR 0.2253; 95% CI [0.05456-0.7681]; p = 0.0253). An endothermal heat-induced thrombosis (EHIT) ≥ grade 2 was observed in three cases (1.1%).ConclusionsA co-treatment of the tributaries is feasible and could improve the technical success of EVLA if a prophylactic closure of these veins is desired, especially if their distance to the SFJ is short. Its effect on the recurrence rate needs further research.
| S-EPMC7790536 | biostudies-literature
Project description:IntroductionTraditional bone surgery using saws and chisels is associated with direct contact of instruments with the bone causing friction, heat and pressure and hence, damaging the bone and the surrounding soft tissues.MethodCold ablation laser osteotomy offers new possibilities to perform corrective osteotomies in the field of bone surgery. We introduce the technology of navigated cold ablation robot-guided laser osteotomy, present potential applications, and preliminary pre-clinical cadaver test results in the field of hand-, wrist- and forearm surgery.ResultsThe cadaver tests showed first promising results for corrections in all planes and axes using different cutting patterns.ConclusionCold ablation laser osteotomy seems to be a feasible new method to perform osteotomies in the field of hand-, wrist- and forearm surgery. Primary osseous stability could be achieved using various cutting patterns which could lead to reduction of the amount of hardware required for osteosynthesis. Further tests are required to proof the latter and precision.
| S-EPMC9541476 | biostudies-literature
Project description:Cancer nanotechnology is emerging as one of the promising strategies combining photothermal therapy (PTT) and photoacoustic imaging (PAI) for the treatment of breast cancer and it has received considerable attention in the recent years because it is minimally invasive, prevents damage to non-targeted regions, permits fast recovery, and involves breast cancer imaging. The present study demonstrates multifunctional biocompatible chitosan-polypyrrole nanocomposites (CS-PPy NCs) as novel agents for photoacoustic imaging-guided photothermal ablation of cancer because of their biocompatibility, conductivity, stability, and strong near-infrared (NIR) absorbance. The CS-PPy NCs are spherical in shape and range 26-94 nm in size with a mean value of 50.54 ± 2.56 nm. The in vitro results demonstrated good biocompatibility of CS-PPy NCs, which can be used in PTT for cancer cells under 808-nm NIR laser irradiation. Tumor-bearing mice fully recovered after treatment with CS-PPy NCs and NIR 808-nm laser irradiation compared to the corresponding control groups. Our research highlights the promising potential of using CS-PPy NCs for photoacoustic imaging-guided photothermal ablation of cancer in preclinical animals, which should be verified in future clinical trials.
| S-EPMC5333628 | biostudies-literature
Project description:ObjectiveThe authors of this study evaluated the safety and efficacy of stereotactic laser ablation (SLA) for the treatment of drug-resistant epilepsy (DRE) in children.MethodsSeventeen North American centers were enrolled in the study. Data for pediatric patients with DRE who had been treated with SLA between 2008 and 2018 were retrospectively reviewed.ResultsA total of 225 patients, mean age 12.8 ± 5.8 years, were identified. Target-of-interest (TOI) locations included extratemporal (44.4%), temporal neocortical (8.4%), mesiotemporal (23.1%), hypothalamic (14.2%), and callosal (9.8%). Visualase and NeuroBlate SLA systems were used in 199 and 26 cases, respectively. Procedure goals included ablation (149 cases), disconnection (63), or both (13). The mean follow-up was 27 ± 20.4 months. Improvement in targeted seizure type (TST) was seen in 179 (84.0%) patients. Engel classification was reported for 167 (74.2%) patients; excluding the palliative cases, 74 (49.7%), 35 (23.5%), 10 (6.7%), and 30 (20.1%) patients had Engel class I, II, III, and IV outcomes, respectively. For patients with a follow-up ≥ 12 months, 25 (51.0%), 18 (36.7%), 3 (6.1%), and 3 (6.1%) had Engel class I, II, III, and IV outcomes, respectively. Patients with a history of pre-SLA surgery related to the TOI, a pathology of malformation of cortical development, and 2+ trajectories per TOI were more likely to experience no improvement in seizure frequency and/or to have an unfavorable outcome. A greater number of smaller thermal lesions was associated with greater improvement in TST. Thirty (13.3%) patients experienced 51 short-term complications including malpositioned catheter (3 cases), intracranial hemorrhage (2), transient neurological deficit (19), permanent neurological deficit (3), symptomatic perilesional edema (6), hydrocephalus (1), CSF leakage (1), wound infection (2), unplanned ICU stay (5), and unplanned 30-day readmission (9). The relative incidence of complications was higher in the hypothalamic target location. Target volume, number of laser trajectories, number or size of thermal lesions, or use of perioperative steroids did not have a significant effect on short-term complications.ConclusionsSLA appears to be an effective and well-tolerated treatment option for children with DRE. Large-volume prospective studies are needed to better understand the indications for treatment and demonstrate the long-term efficacy of SLA in this population.
| S-EPMC10193482 | biostudies-literature