Brain tissue perfusion monitoring using Sonopod for transcranial color duplex sonography

Abstract

Objective

We have introduced and improved a transducer holder, named the Sonopod, for transcranial color duplex sonography (TCDS) monitoring via both temporal/foraminal windows (TW/FW). The objective is to clarify clinical usefulness and identify problems in TCDS-Sonopod monitoring during the evaluation of brain tissue perfusion.

Methods

Brain tissue perfusion monitoring was evaluated in 11 patients (ages 31–94, mean 66). After a bolus intravenous Levovist^®, power modulation imaging (PMI) in all cases was evaluated in comparison with second harmonic imaging (SHI) in two cases at the diencephalic horizontal plain via the TWs on the basis of time–intensity curves (TICs) in five regions of interest (ROIs); bilateral basal ganglia (BG) and thalamus (Th), and contra-lateral temporal lobe (TL). After a SONOS5500 S3 transducer was installed in the Sonopod, acetazolamide (ACZ) cerebral vasoreactivity utilizing PMI was evaluated in 10 cases via the bilateral (five cases) and unilateral (five cases) TWs. A total of 30 TICs were evaluated before/after ACZ administration.

Results

(1) All patients could be monitored continuously by one examiner. (2) We confirmed that PMI proves superior to SHI in quantitative evaluation of the bilateral hemispheres via the unilateral TWs. (3) Brain tissue perfusion could be precisely quantified before/after ACZ in the same ROIs. (4) TIC base-line drifts during monitoring were observed in 4 (seven TICs) of 10 (30 TICs) patients. However, fixed-probe shifts during monitoring were easily readjustable and the TIC recovered to the base-line in all cases. (5) Due to re-fixation needed for contralateral TW monitoring, it was not possible to evaluate completely in the same ROIs.

Conclusions

TCDS-Sonopod monitoring succeeds in continuously and quantitatively evaluating precise and reproducible intracranial hemodynamics in the brain tissue.