Understanding the Advanced Signal Processing Technique of Real-Time Adaptive Filters

Diagnostic ultrasound manufacturers are advancing the technology of sonographic systems, providing superior image quality and improving the diagnostic confidence for both sonographers and radiologists. Real-time adaptive filters (RTAFs) are perhaps the least known among the advanced signal processing techniques available on most modern sonography machines, which is further complicated by the fact that RTAF appears under various trademark names. Despite the different proprietary names, RTAFs generally employ a postprocessing mathematical algorithm to real-time imaging that improves contrast resolution by reducing noise and artifacts while simultaneously enhancing the edges and smoothing the tissue texture of structures. This technique may be applied across a wide variety of clinical examinations and may not yet be completely understood and appreciated by sonographers. This review aims to educate readers on how RTAFs work, supported by examples of their benefit to image quality. In particular, the authors describe the effectiveness of using RTAF for superficial structures (thyroid, abdominal wall), deep structures (abdomen, pelvis), and dynamic examinations, including musculoskeletal and vascular applications.