Evaluating a modified delay-multiply-and-sum reconstruction algorithm to improve detection of osteochondritis dissecans

Abstract

Osteochondritis dissecans (OCD) is a focal joint defect that is prevalent among youth athletes. With the application of medical ultrasound, OCD of the humeral capitellum could be detected earlier and prevent surgery. In this work, we tested a modified Delay-Multiply-and-Sum (DMAS) reconstruction algorithm to evaluate how it affects medical ultrasound’s ability to detect OCD. Starting with the DMAS reconstruction algorithm described by Matrone et al. (2015), we modified the implementation of filtering and envelope detection steps. Delay-and-Sum (DAS), DMAS, and modified DMAS algorithms were tested on phantom and cadaveric models of capitellar OCD. The DMAS and modified DMAS images were histogram matched to the DAS image for quantitative comparison. By taking several profiles across the images of the artificial OCD lesions, we compared the lesion contrast and bone surface clarity produced by each algorithm. We found that the unmodified DMAS algorithm showed little improvement over the DAS algorithm, particularly after histogram matching. The modified DMAS algorithm showed a much greater improvement in the detection of OCD lesions compared to the DMAS algorithm. This modified DMAS algorithm could be used for other bone surface imaging applications. Future work includes evaluating these algorithms in vivo with patients diagnosed with OCD.