Noninvasive detection of atherosclerosis by arterio-oscillo-gram

In this paper, a new biosignal, naming arterio-oscillo-gram (AOG) is introduced that recorded noninvasively by placing an accelerometer transducer over brachial artery. The artery is narrowed by a cuff inflated at mean blood pressure. The relation of AOG with hemodynamic of cardiovascular system is characterized conceptually by presenting a model. Ten seconds of AOG was recorded for 51 persons including 22 normal, 22 'coronary artery disease' (CAD), and 7 'other mechanical heart disorders' (OMHD) patients, which have some systolic and/or diastolic murmurs. The spectrum of each AOG signal was estimated via Welch's method over 0.07-s segments. Due to atherosclerosis, the normalized energy of AOG in 30-250 Hz range for CAD patients was higher than normal cases. By comparing this spectral feature (F) with a threshold, and attending to angiography's findings, CAD and non-CAD cases were correctly diagnosed by accuracies of about 73% (16/22) and 90% (26/29 i.e. 20/22 for normal and 6/7 for OMHD), respectively. In contrast to phonocardiogram-based methods, this practical approach does not depend to diastolic murmurs and turbulence of coronary arteries. This method can be used as a simple screening tool, since the more atherosclerosis severity, the more F.