An initial experience with post-data processing in hepatic sonography.

Abstract

Sonographic image manipulation became a possibility with the advent of digital equipment. Depending on the manufacturer, this manipulation may be called pre-data processing, post-data processing, or both. It involves changing the normal assigned gray scale curve to accentuate defined decibel ranges. Sixty consecutive patients were examined who had technically adequate hepatic sonograms using the normal linear gray scale range and post-data processing (PDP). Sonograms were considered normal in 32 patients, while 28 were believed abnormal. In 10 of the 28 abnormal scans, hepatic metastases were better visualized with post-data processing (one false-positive). These were patients in whom there was a minimal echogenic difference between the surrounding normal liver and the lesion. However, in no case was a lesion seen after post-data processing that was not recognizable on the linear gray scale scan. In the other 18 abnormal scans (one false-positive study), the echogenic difference between the lesion and the liver was large enough that PDP was not helpful. The possible pitfalls in the use of PDP, such as poor technique, are discussed and demonstrated. Improvement in hepatic sonographic sensitivity will require more fundamental improvement of equipment than provided by post-data processing.