0041: Ultrasound Enhanced Thrombolysis

Holland, Christy K.; Ammi, Azzdine Y.; Datta, Saurabh; Perrin, Stephen R.; Beiler, Shauna; Beiler, Christian; Wagner, Kenneth R.

doi:10.1016/j.ultrasmedbio.2009.06.030

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When confined spatial targeting is less critical, simpler approaches have been proposed (Deffieux and Konofagou, 2010). In particular, ultrasound enhanced thrombolysis (UET) in acute ischemic stroke patients generally can be achieved with a mechanical index in the diagnostic range (Holland et al, 2011; Meairs et al, 2012). Therefore, weakly focused beams can be used to enhance thrombolysis without adverse effects in intervening tissues.…”

Section: Introductionmentioning

confidence: 99%

In silico Study of Low-Frequency Transcranial Ultrasound Fields in Acute Ischemic Stroke Patients

Bouchoux

Shivashankar

Abruzzo

et al. 2014

Ultrasound in Medicine & Biology

Self Cite

View full text Add to dashboard Cite

Ultrasound in the sub-megahertz range enhances thrombolysis and may be applied transcranially to ischemic stroke patients. The consistency of transcranial insonification needs to be evaluated. Acoustic and thermal simulations based on computed-tomography (CT) scans of 20 patients were performed. An unfocused 120-kHz transducer allowed homogeneous insonification of the thrombus, and positioning based on external landmarks performed similarly to an optimized placement based on CT data. With a weakly focused 500-kHz transducer, the landmark-based positioning underperformed. The predicted inter-patient variation of in situ acoustic pressure was similar with both transducers for the optimized placement (18.0–26.4% relative standard deviation). The simulated maximum acoustic pressure in intervening tissues was 2.6±0.6 and 2.0±0.7 times the pressure in the thrombus for the 120-kHz and 500-kHz transducers, respectively. A 1 W/cm2 insonification of the thrombus caused a 3.8±2.2°C temperature increase in the bone for the 120-kHz transducer, and a 13.4±3.3°C increase for the 500-kHz transducer. Contralateral local maxima up to 1.1 times the pressure amplitude in the targeted zone were predicted for the 120-kHz transducer. We established two transducer placement approaches, one based on analysis of a head CT and the other using simple external, visible landmarks. Both approaches allowed consistent insonification of the thrombus.

show abstract

Section: Introductionmentioning

confidence: 99%

In silico Study of Low-Frequency Transcranial Ultrasound Fields in Acute Ischemic Stroke Patients

Bouchoux

Shivashankar

Abruzzo

et al. 2014

Ultrasound in Medicine & Biology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ultrasound is a promising adjuvant to thrombolysis with rtPA. The efficiency of ultrasound-enhanced thrombolysis (UET) has been demonstrated by several groups and recent advances in this field are reviewed by Holland et al (2011) and Meairs et al (2012). Although the mechanisms involved in UET are not fully understood, cavitation is thought to play an important role.…”

Section: Introductionmentioning

confidence: 99%

Experimental validation of a finite-difference model for the prediction of transcranial ultrasound fields based on CT images

et al. 2012

View full text Add to dashboard Cite

The prevalence of stroke worldwide and the paucity of effective therapies have triggered interest in the use of transcranial ultrasound as an adjuvant to thrombolytic therapy. Previous studies have shown that 120-kHz ultrasound enhanced thrombolysis and allowed efficient penetration through the temporal bone. The objective of our study was to develop an accurate finite-difference model of acoustic propagation through the skull based on computed tomography (CT) images. The computational approach, which neglected shear waves, was compared with a simple analytical model including shear waves. Acoustic pressure fields from a two-element annular array (120 kHz and 60 kHz) were acquired in vitro in four human skulls. Simulations were performed using registered CT scans and a source term determined by acoustic holography. Mean errors below 14% were found between simulated pressure fields and corresponding measurements. Intracranial peak pressures were systematically underestimated and reflections from the contralateral bone were overestimated. Determination of the acoustic impedance of the bone from the CT images was the likely source of error. High correlation between predictions and measurements (R2=0.93 and R2=0.88 for transmitted and reflected waves amplitude, respectively) demonstrated that this model is suitable for quantitative estimation of acoustic fields generated during 40-200 kHz ultrasound-enhanced ischemic stroke treatment.

show abstract

0041: Ultrasound Enhanced Thrombolysis

Cited by 2 publications

References 0 publications

In silico Study of Low-Frequency Transcranial Ultrasound Fields in Acute Ischemic Stroke Patients

In silico Study of Low-Frequency Transcranial Ultrasound Fields in Acute Ischemic Stroke Patients

Experimental validation of a finite-difference model for the prediction of transcranial ultrasound fields based on CT images

Contact Info

Product

Resources

About