Improved Ultrasound Imaging for Knee Osteoarthritis Detection

Abstract

Knee Osteoarthritis (OA) is most common compare to other joint OA. Ultrasound (US) imaging has a number of benefits over other medical imaging modalities. There is a significant change in the shape of cartilage due to the progression of knee OA and its associated cartilage degeneration. By using US imaging, it is possible to detect knee joint space narrowing. Nevertheless, the low contrast ratio and presence of speckle noise limit the application of US imaging. This book will present a new contrast enhancing and speckle noise reducing method which will overcome the existing limitations of US medical imaging. In this method, for contrast enhancement, optimum values of contrast, brightness and detail preservation will be considered. Most of the conventional contrast enhancing methods emphasizes only one character; in contrast, the proposed method involves establishing a separating point to segment histogram for optimal contrast, brightness and detail preservation simultaneously. Three metrics will be used in this optimization, namely Preservation of Brightness Score function (PBS), Optimum Contrast Score function (OCS), and Preservation of Detail Score function (PDS), each of which will be defined. To both reduce speckle noise and preserve edge features, anisotropic diffusion (AD) method has been improved by using a new diffusivity function and four gradient thresholds instead of one. For analyzing the performance of the proposed method, quantitative and qualitative analysis has been performed using real ultrasound images. Results prove that the proposed method out-performs other existing methods.