Application of the Power Spectrum Estimation in the Ankle-brachial Index Detection

The key of ankle-brachial index (ABI) measurement is accurately measurement of upper and lower extremities systolic pressure. When the blood flow is blocked, blood flow will resume a normal beat and the corresponding cuff pressure of the first trough starting point is the systolic pressure. First it detects the pulse signal main frequency by spectral analysis of the pulse signal which based on the power spectrum estimation. Regarding pulse signal frequency as the basic standard, it achieves power spectrum estimation of blood flow signal with a sliding window. Last it achieves locating the position of systolic pressure by detecting whether the blood flow signal frequency and the pulse signal frequency are the same. Through simulation and experiments, it can achieve accurate detection of systolic pressure and automatic measurement of ankle-brachial index by application of this method.