Strain estimation in abdominal aortic aneurysms from 2-D ultrasound

The rupture risk of abdominal aortic aneurysms (AAAs) is routinely inferred from the maximum diameter of the AAA. However, clinical experience indicates that this criterion has poor accuracy and that noninvasive assessment of the elastic properties of the vessel might give better correspondence with the rupture risk. We have developed a method for analysis of circumferential strain in AAAs from sequences of cross-sectional ultrasound B-mode images. The algorithm is fast, semiautomatic and well-suited for real-time applications. The method was developed and evaluated using data from 10 AAA patients. The preliminary results demonstrate that the method is sufficiently accurate and robust for clinically acquired data. An important finding is that local strain values may exceed the circumferential average strain significantly. Furthermore, the calculated strain shows no apparent covariation with the diagnosed diameter. This implies that the method may give new and essential information on the clinical condition of the AAA.