Pulse-wave timing between the cervical carotid and intracranial arteries by means of wavelet transform

The Wavelet Transform (WT), is applied in a method for timing the blood pulse wave between the internal carotid artery and one of the intracranial arteries. The required accuracy is a few milliseconds. In contrast to the Fourier Transform (FT), WT is an appropriate technique for the detection of nonstationary events. This pilot study deals with an application of the WT in simultaneous ultrasound Doppler recordings of the internal carotid artery, intracranial arteries and an electrocardiographic (ECG) signal. The results showed a beat-to-beat precision of SD=2-7 ms which is higher than comparable readings from conventional Doppler spectral measurements. The pulse wave transfer time is related to the compliance of the arterial wall and may be sensitive for the early onset of vasospasm in subarachnoid haemorrhage and embolic phenomena