Abstract
The present study was aimed to obtain images of the basal cerebral arteries and to determine the true angle between the Doppler beam and the blood column of these arteries, using a pulsed mutigated Doppler system with B-mode scanner (transcranial real-time color-flow Doppler ultrasonography, TRCD). Then, correction of the flow velocity was performed to obtain the absolute flow velocity.
Fifteen healthy volunteers (5 males and 10 females) with the age ranging rom 20 to 41 years old were examined with the pulsed Doppler system incorporated into a B-mode ultrasonic scanner with 2.5 MHz emtting frequency (SSH160A, Toshiba Medical Systems Co., Ltd.). The probe was positioned just superior to the zygomatic arch and anterior to the ear external canal.
The horizontal portion of the middle cerebral artery (MCA) was clearly delineated as a red curved stream. At an average angle to the Doppler beam of 52 degrees, corrected mean velocity of the horizontal portion of MCA was 92 cm/sec at an average depth of 54 mm. The true angle between the Doppler beam and the direction of blood flow in the vessel of interest is necessary for correction of flow velocity, because the incident angle to MCA is much larger than that previously reported by Aslied et al (0-20 degree).
The use of TRCD permits more accurate non-invasive quantification of cerebral hemodynamic consequences than the previuos method.
