Classification of Doppler Ultrasound Blood Flow Signals of Lower Extremity Arteries for the Early Detection of Diabetic Foot

Peripheral arterial disease is one of the key indicators of diabetic foot, which can be easily identified by ultrasound diagnostic techniques. The work aims to detect diabetic foot in early stages by classifying the blood flow signals of lower extremity arteries being captured by ultrasound doppler methods. Samples are collected from diabetic patients with and without having probable symptoms of arterial diseases. Doppler examination has been conducted on posterior tibial artery for 354 subjects with a transducer of 8 MHz frequency. The auscultation, method of listening sounds of internal organs, is employed as medical diagnostic tool for identifying pathological conditions. Each artery in the human body has a unique profile of Doppler flow. This fixed profile may be changed with the presence of a particular disease. The received signal has a spectrum of Doppler-shifted signals with respect to the existence of a velocity profile across the vessel lumen. Changes to the shape of this profile is an indicator of the severity of disease. Various features are extracted by using various statistical and signal processing functions. The feature analysis was accomplished with machine learning algorithms. Naïve Bayes, Tree and SVM algorithms are employed with MATLAB Toolboxes. Comparing the performance of these algorithms, the Tree method is found superior than the others. So, the proposed classification methodology can be employed as a key factor for the early stage detection of diabetic foot. As diabetic foot is correlated with many other parameters which effects the pressure and flow velocity of lower extremities, an integrated disease prediction model is proposed by incorporating the ultrasound doppler technique.