Clinical evaluation of a digital signal-processing device for real-time speckle suppression in medical ultrasonics.

Although the field of medical ultrasound imaging has experienced significant advances during the last few years, ultrasound images still suffer from a type of acoustic noise called speckle, which represents a major source of image quality degradation (Kremkau & Taylor, 1986). Speckle is an interference effect caused by the addition by the transducer of echoes scattered by tissue inhomogeneities of size and spacing too fine to be resolved (Morrison et al, 1980; Wells & Halliwell, 1981). The resulting granular pattern depends on both the imaging system and the tissue being imaged in such a complicated way that, although it could be possible to use the statistical properties of speckle for tissue characterization (Wagner et al, 1987), a human observer cannot isolate the true tissue information simply by visual inspection of the image. There are several reasons that make a speckle-free image desirable. 1. Speckle limits the resolution of small structures and reduces the ability of a human observer to detect l...