Ultrasound image-based estimation system for arteriosclerosis of in vivo blood vessels

With aging, the mechanical properties of a blood vessel degrade; its strength and elongation decreases. However, its stiffness (stress/strain) increases. Also the rate of hardening of the vessel depends on the individual. It is an urgent task to establish an inspection technique for strength parameters as hardening progresses. This report presents such a technique for estimating sclerosis of in vivo blood vessel with ultrasound B-mode image. The method is based on in vivo stiffness (Eth) calculated from variations in vessel diameter with changes in systolic and diastolic blood pressures. In addition, we obtained a correlation between Eth and strength (¿_u) from the results of tensile and internal pressure tests using some animal model and human artery specimens. Therefore, we can estimate in vivo Eth and ¿_u of an artery using B-mode image and an associated correlation curve. To simplify the measurement of changes in diameter, prototype software was developed. To examine the validity of this technique, clinical data was collected at some hospitals. The results indicated that Eth and ¿_u are useful symptom indices for arteriosclerosis, particularly for identifying the beginning of sclerosis in patients in their early twenties.