Hardware-Independent Deep Signal Processing: A Feasibility Study in Echocardiography

Deep learning (DL) models have emerged as alternative methods to conventional ultrasound (US) signal processing, offering the potential to mimic signal processing chains, reduce inference time, and enable the portability of processing chains across hardware. This article proposes a DL model that replicates the fine-tuned BMode signal processing chain of a high-end US system and explores the potential of using it with a different probe and a lower end system. A deep neural network (DNN) was trained in a supervised manner to map raw beamformed in-phase and quadrature component data into processed images. The dataset consisted of 30 000 cardiac image frames acquired using the GE HealthCare Vivid E95 system with the 4Vc-D matrix array probe. The signal processing chain includes depth-dependent bandpass filtering, elevation compounding, frequency compounding, and image compression and filtering. The results indicate that a lightweight DL model can accurately replicate the signal processing chain of a commercial scanner for a given application. Evaluation on a 15-patient test dataset of about 3000 image frames gave a structural similarity index measure (SSIM) of 98.56 ± 0.49. Applying the DL model to data from another probe showed equivalent or improved image quality. This indicates that a single DL model may be used for a set of probes on a given system that targets the same application, which could be a cost-effective tuning and implementation strategy for vendors. Furthermore, the DL model enhanced image quality on a Verasonics dataset, suggesting the potential to port features from high-end US systems to lower end counterparts.