Transcranial color-coded Doppler (TCCD) is a real-time scanning method which evaluates intracranial vessels at high resolution. Whereas transcranial Doppler (TCD) cannot adjust the insonation angle between the ultrasonic wave and blood flow, TCCD can directly view the flow direction so that more accurate flow velocity can be derived. Meanwhile, it is necessary to compare the reference value of the parameters in each test. Methods: Subjects with normal magnetic resonance angiography and TCD were

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... enrolled in neurology clinics. Three test methods were applied for the measurement of middle cerebral arteries (MCAs): 1) Blind-TCD: Blind technique, 2) Image-TCCD: Image-based, and 3) AC-TCCD: angle corrected. Four sample points with depths of 65-48 mm were evaluated with indices including mean flow velocity (MFV), peak systolic velocity (Vs), end diastolic velocity (Vd), and pulsatility index (PI). Results: Thirty patients with age of 61±17 years were enrolled. MFVs at four depths of MCA were 58±10 (Blind-TCD), 54±10 (Image-TCCD), and 59±12 cm/s (AC-TC-CD). There were no significant differences in the MFVs between Blind-TCD and AC-TCCD (p=0.212). The Vs were 87±17 (Blind-TCD), 90±17 (Image-TCCD) and 99±21 cm/sec (AC-TCCD) with significant differences (p<0.05). The Vs increased in 14% at AC-TCCD over Blind-TCD. PI over age 65 in AC-TCCD was 20% higher than Blind-TCD. Conclusion: Peak systolic velocity can be measured more accurately by AC-TCCD. Image-TCCD and AC-TCCD with small sample volumes are advantageous in that they reflect the change of depth-dependent blood flow more sensitively.