The feasibility of ultrasound‐assisted endovascular laser thrombolysis in an acute rabbit thrombosis model

Abstract

Purpose This study aimed to test the feasibility of combined ultrasound and laser technique, namely, ultrasound‐assisted endovascular laser thrombolysis (USELT), for thrombolysis by conducting in vivo tests in a rabbit thrombosis model. Materials and methods An acute thrombus was created in the right jugular vein of rabbit and then was treated with ultrasound only, laser only, and USELT to dissolve the blood clot. A total of 20 rabbits were used. Out of which, the first three rabbits were used to titrate the laser and ultrasound parameters. Then, five rabbits were treated with ultrasound only, five rabbits were treated with laser only, and seven rabbits were treated with USELT. During USELT, 532‐nm laser pulses were delivered endovascularly directly to the clot through a fiber optic, and 0.5 MHz ultrasound pulses were applied noninvasively to the same region. A laser fluence of 4 to 12 mJ/cm2 and ultrasound amplitude of 1 to 2 MPa were used. Recanalization of the jugular vein was assessed by performing ultrasound Doppler imaging immediately after the treatment. The maximum blood flow speed after the treatment as compared to its value before the treatment was used to calculate the blood flow recovery in vessel. Results The blood flow was fully recovered (100%) in three rabbits, partially recovered in two rabbits (more than 50% and less than 100%) with mean percentage recovery of 69.73% and poorly recovered in two rabbits (<50%) with mean percentage recovery of 6.2% in the USELT group. In contrast, the treatment group with ultrasound or laser alone did not show recanalization of vein in any case, all the five rabbits were poorly/not recovered with a mean percentage recovery of 0%. Conclusions The USELT technology was shown to effectively dissolve the blood clots in an acute rabbit jugular vein thrombosis model.

Feasibility of photoacoustic‐guided ultrasound treatment for port wine stains

“…The computational studies in this study demonstrate the methodology and the efficacy of time‐reversal guided US focusing for noninvasive PWS birthmarks treatment with minimal effect on neighboring tissue. The proposed strategy could also benefit existing methodologies for US sonication which use microbubbles for rupturing blood vessels 35,36 and for improved permeability for intravascular delivery of gene therapy and medications 37 . The methodology can also assist other targeted US therapeutic techniques aiming awound healing and cancer therapy 38–41 .…”

“…The time‐reversal‐based focusing as demonstrated in this manuscript facilitates US focusing onto the optical absorption map. The proposed strategy could also be used with the existing methodology of US sonication using microbubbles for rupturing blood vessels, 34‐36 as well as for improving permeability for intravascular delivery of gene therapy and medications 37 . This methodology can also assist other targeted US therapeutic techniques aimed at wound healing and cancer therapy 38‐41 …”

The Updated Role of Transcranial Ultrasound Neuromodulation in Ischemic Stroke: From Clinical and Basic Research

“…These bubbles rapidly vibrate, expand, and burst. A large amount of energy is released at the moment of bubble explosion, causing the thrombus to tear and decompose, exposing the surface of the thrombus in large quantities, and further accelerating the dissolution of the thrombus (Ma et al, 2020;Jo et al, 2021;Singh et al, 2021). The cavitation-induced thermal effect has been confirmed as a potential mechanism underlying this phenomenon.…”

Recent Advances in Targeted Nanotherapies for Ischemic Stroke

“…55 Since a thrombus has higher light absorption at certain wavelengths than surrounding tissues and structures, laser thrombolysis can induce precise cavitation. Singh et al 56 designed a combined ultrasound and laser-based thrombolysis system (USELT) and evaluated its thrombolytic potential in a rabbit model. In USELT, the laser wavelength can be tuned to maximize absorption and clot heating.…”