Dataset Information

Ultrasound-assisted laser thrombolysis with endovascular laser and high-intensity focused ultrasound.

ABSTRACT:

Purpose

The combination of laser and ultrasound can significantly improve the efficiency of thrombolysis through an enhanced cavitation effect. We developed a fiber optics-based laser-ultrasound thrombolysis device and tested the feasibility and efficiency of this technology for restoring blood flow in an in vitro blood clot model.

Methods

An in vitro blood flow-clot model was setup, and then an endovascular laser thrombolysis system was combined with high-intensity focused ultrasound to remove the clot. The laser and ultrasound pulses were synchronized and delivered to the blood clot concurrently. The laser pulses of 532 nm were delivered to the blood clot endovascularly through an optical fiber, whereas the ultrasound pulses of 0.5 MHz were applied noninvasively to the same region. Effectiveness of thrombolysis was evaluated by the ability to restore blood flow, which was monitored by ultrasound Doppler.

Results

As laser powers increased, the ultrasound threshold pressures for effective thrombolysis decreased. For laser fluence levels of 0, 2, and 4 mJ/cm² , the average negative ultrasound threshold pressures were 1.26 ± 0.114, 1.05 ± 0.181, and 0.59 ± 0.074 MPa, respectively. The periods of time needed to achieve effective thrombolysis were measured at 0.8, 2, and 4 mJ/cm² laser fluence levels and 0.42, 0.70, and 0.98 MPa negative ultrasound pressures. In general, thrombolysis could be achieved more rapidly with higher laser powers or ultrasound pressures.

Conclusions

Effective thrombolysis can be achieved by combining endovascular laser with noninvasive ultrasound at relatively low power and pressure levels, which can potentially improve both the treatment efficiency and safety.

SUBMITTER: Jo J

PROVIDER: S-EPMC9382677 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Publications

Ultrasound-assisted laser thrombolysis with endovascular laser and high-intensity focused ultrasound.

Jo Janggun J Forrest M Laird ML Yang Xinmai X

Medical physics 20201218 2

<h4>Purpose</h4>The combination of laser and ultrasound can significantly improve the efficiency of thrombolysis through an enhanced cavitation effect. We developed a fiber optics-based laser-ultrasound thrombolysis device and tested the feasibility and efficiency of this technology for restoring blood flow in an in vitro blood clot model.<h4>Methods</h4>An in vitro blood flow-clot model was setup, and then an endovascular laser thrombolysis system was combined with high-intensity focused ultras ...[more]

PMID: 33280145

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Project description:BackgroundHigh-intensity focused ultrasound (HIFU) is considered to be an alternative to surgery. Extracorporeal ultrasound-guided HIFU (USgFU) has been clinically used to treat solid tumors. Preliminary trials in a small sample of a Western population suggested that this modality was safe. Most trials are performed in China thereby providing comprehensive data for understanding the safety profile. The aim of this study was to evaluate adverse events of USgFU therapy.Methods and findingsClinical data were searched in 2 Chinese databases. Adverse events of USgFU were summarized and compared with those of magnetic resonance-guided HIFU (MRgFU; for uterine, bone or breast tumor) and transrectal ultrasound-guided HIFU (for prostate cancer or benign prostate hyperplasia). USgFU treatment was performed using 7 types of device. Side effects were evaluated in 13262 cases. There were fewer adverse events in benign lesions than in malignant lesions (11.81% vs. 21.65%, p<0.0001). Rates of adverse events greatly varied between the disease types (0-280%, p<0.0001) and between the applied HIFU devices in both malignant (10.58-44.38%, p<0.0001) and benign lesions (1.67-17.57%, p<0.0001). Chronological analysis did not demonstrate a decrease in the rate of adverse events. Based upon evaluable adverse events, incidences in USgFU were consistent with those in MRgFU or transrectal HIFU. Some side effects frequently occurred following transrectal HIFU were not reported in USgFU. Several events including intrahepatic metastasis, intraoperative high fever, and occlusions of the superior mesenteric artery should be of particular concern because they have not been previously noted. The types of adverse events suggested that they were ultrasonic lesions.ConclusionThe frequency of adverse events depended on the location of the lesion and the type of HIFU device; however, side effects of USgFU were not yet understood. USgFU did not decrease the incidence of adverse events compared with MRgFU.

Project description:The success of any minimally invasive treatment procedure can be enhanced significantly if combined with a robust noninvasive imaging modality that can monitor therapy in real time. Quantitative ultrasound (QUS) imaging has been widely investigated for monitoring various treatment responses such as chemotherapy, radiation, and thermal therapy. Previously, we demonstrated the feasibility of using spectral-based QUS parameters to monitor high-intensity focused ultrasound (HIFU) treatment of in situ tumors in euthanized rats [Ultrasonic Imaging 36(4), 239-255, 2014]. In the present study, we examined the use of spectral-based QUS parameters to monitor HIFU treatment of in vivo rat mammary adenocarcinoma tumors (MAT) where significant tissue motion was present. HIFU was applied to tumors in rats using a single-element transducer. During the off part of the HIFU duty cycle, ultrasound backscatter was recorded from the tumors using a linear array co-aligned with the HIFU focus. A total of 10 rats were treated with HIFU in this study with an additional sham-treated rat. Spectral parameters from the backscatter coefficient, i.e., effective scatterer diameter (ESD) and effective acoustic concentration (EAC), were estimated. The changes of each parameter during treatment were compared with a temperature profile recorded by a fine-needle thermocouple inserted into the tumor a few millimeters behind the focus of the HIFU transducer. The mean ESD changed from 121 ±6 to [Formula: see text], and the EAC changed from 33 ±2 to [Formula: see text] during HIFU exposure as the temperature increased on average from 38.7 ±1.0 (°)C to 64.2 ±2.7 (°)C. The changes in ESD and EAC were linearly correlated with the changes in tissue temperature during the treatment. When HIFU was turned off, the ESD increased from 81 ±8 to [Formula: see text] and the EAC dropped from 46 ±3 to 36±2 dB/cm(3) as the temperature decreased from 64.2 ±2.7 (°)C to 45 ±2.7 (°)C. QUS was demonstrated in vivo to track temperature elevations caused by HIFU exposure.

Dataset Information

Ultrasound-assisted laser thrombolysis with endovascular laser and high-intensity focused ultrasound.

Purpose

Methods

Results

Conclusions

Publications

Ultrasound-assisted laser thrombolysis with endovascular laser and high-intensity focused ultrasound.

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