Quantitative Assessment of Tendon Backscatter Anisotropy in B-mode Ultrasound

We will describe the use of B-mode backscatter anisotropy to evaluate tendons or muscles for pathology that disrupts or obscures the normal architecture. The method is very straightforward, simple to use, and can be applied toward any tissue that contains a pattern of reflectors that has a geometry that appears regular to an ultrasound beam. Muscle and tendon fibers meet this criterion very well. All one needs to do is image the target and systematically steer the ultrasound beam taking representative images of the target at different angles. This is very similar to what is done in Doppler flow imaging. The backscattered signal amplitude falls off as the beam is steered away from normal to the regular structures. The rate at which the signal falls off can be used as a quantitative metric for evaluating the tissue. We show how this method works in distinguishing normal patellar tendons from those with chronic tendinopathy. The method performs very well and easily distinguishes normal tendons from those with tendinopathy.