HIGH-FREQUENCY ULTRASOUND IMAGING AND SPECTRAL-ANALYSIS IN TRAUMATIC HYPHEMA

Purpose: High-frequency (50-MHz) ultrasound allows high-resolution ima ging of anterior ocular structures. Spectrum analysis of acoustic back scatter is sensitive to the concentration, size, and density of tissue inhomogeneities. The authors sought to determine whether acoustic ima ging and spectrum analysis of hyphema would allow them to distinguish organized from fluid hyphema and recent from old hemorrhage in the eye . Methods: Trauma-induced hyphemas were followed by slit-lamp photogra phy and high-frequency ultrasonography in six New Zealand white rabbit s. The blood collections were analyzed using the normalized power spec tra of the digitized radio frequency ultrasound data and compared with in vitro references. Results: The 50-MHz acoustic images permitted di fferentiation between fluid (diffuse) and clotted (organized) blood. S pectrum analysis allowed quantitative characterization of the degree o f blood organization. Significant changes were observed in spectral pr operties during the time course of absorption both for initial and aft er-rebleeding hemorrhages. The characteristics of a human postsurgical hyphema also were examined and found to be similar to those seen in t he experimental model. Conclusion: Spectrum analysis of high-frequency ultrasound data was able to distinguish organized from recent hemorrh age, which is clinically helpful for planning hyphema therapy.