IJCNMH ARCpublishing

Issue: Issue 1 (2014) – Supplement 1

Original Article

Transcranial targeting low frequency ultrasound thrombolysis system: evaluation of the probe fixation devices for blood flow monitoring

Jun Shimizu, Hidetaka Mitsumurab, Ayumi Arai, Jun Kubotaa, Takashi Azuma, Takeki Ogawa, and Hiroshi Furuhata
Background: We developed the transcranial targeting low frequency ultrasound thrombolysis system (TCTLoFUT) which will be used for an acute ischemic stroke (AIS). TCT-LoFUT can emit the T beam (500 kHz continuous waveform, 0.72 W/cm2) for thrombolysis to a target thrombus with the D beam (2 MHz pulsed waveform, 0.72 W/cm2) for diagnostic TC-CFI. We report the in vitro thrombolytic efficacy by TCTLoFUT and estimate the blood flow monitoring in human with a newly developed head-fixture for TCT-LoFUT using a same aspect of commercial probe.

Methods: A) Sonothrombolysis experiment: The 1.25 ml of blood was extracted by the healthy volunteer. The blood in a syringe for 40 min and created a fresh thrombus with a centrifuge (4500 rotation / 5 min). The alteplase concentration in a syringe solution was made to be 358 IU/ml. The intermittent T/D beams were applied under the 60 min of protocol which was described in our studies. The rt-PA independent group (rt-PA, n=39) and the rt-PA + TCT-LoFUT group (rt-PA+US, n=13) were compared. The sound intensity in a syringe was 0.05 W /cm2. B) Blood-flow monitoring evaluation: We evaluated the blood flow monitoring by middle cerebral artery (MCA) detection in 10 healthy volunteers for 30 min. We used the 2.5 MHz TCCFI probe with the fixture which was developed for same aspect of the TCT-LoFUT.

Results: A) Sonothrombolysis experiment: The recanalization rate of 60 min after were 64.1% in rt-PA group and 92.3% in rt-PA+US group. Average recanalization time was shortened from 27.2 min in rt-PA group to 21.4 min in rt-PA+ US group ( p < 0.01). B) Blood-flow monitoring evaluation: The MCA could be detected using the fixture for TCT-LoFUT.

Conclusion: TCT-LoFUT has a function of the blood-flow monitoring simultaneously with a thrombolysis accelerating effect which will be used for AIS patients.

Keywords: Sonothrombolysis, Low frequency, Color flow imaging, Fixation.

International Journal of Clinical Neurosciences and Mental Health 2014; 1(Suppl. 1):S22

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