抄録
[Purpose] It has been reported that the failure rate in recording middle cerebral artery (MCA) flow ranged from 20 to 40%. In our experience, this failure rate was about 10%. The detectability of MCA by transcranial Doppler ultrasonography (TCD) is influenced by several factors: (1) temporal bone thickness. (2) blood flow velocity. (3) pulsatility index. (4) age and sex of patients. (5) branching type of the MCA. (6) hematocrit, PaCO2, systolic blood pressure of the patients. and (7) technique. In this study, we investigated the detectability in 58 vessels of 33 subjects to assess the factors that affect Doppler detectability by TCD. [Materials and Methods] We analyzed three groups classified by the detectability, namely group A (easy detection) and group B (can detect MCA flow within 10 minutes) or group C (impossible to detect) . [Results] The significant factors that influenced the measurement of MCA flow were as follows: presence of thick temporal bone, a low flow velocity, and being an elderly female. The other factors had no apparent significance due to different conditions. [Conclusion] Thickness of the skull and blood flow velocity were considered to be two major factors that make it difficult to detect intracranial blood flow by TCD.
