ULTRASOUND DENSITOMETRIC ANALYSIS - COMPARISON BETWEEN AN ONLINE DIGITAL ACQUISITION ACOUSTIC PROGRAM AND AN OFFLINE ANALOG PROGRAM

Videodensitometric analysis of myocardial contrast echocardiography is traditionally performed off line. Recently, an online contrast ultras ound analysis system, Acoustic Densitometry (Hewlett-Packard), was int roduced. We compared pixel intensities acquired with Acoustic Densitom etry to pixel intensities derived from videodensitometry. A tissue pha ntom was imaged in phase I using three transducer frequencies (2.5, 3. 5, and 5.0 MHz). In phase II, an in vitro flowing tube model with vari ous concentrations of Albunex(R) was imaged at two flow rates, 0.6 and 1.2 m/sec, and at two transducer frequencies, 2.5 and 3.5 MHz. The re lationship between pixel intensities yielded by the two systems for id entical ultrasound signals was determined with linear regression. Inte nsities derived with Acoustic Densitometry strongly correlated with th ose derived from the offline videodensitometry system. The intensities were related by a predictive multiplicative factor based on display c haracteristics of the two systems. These results suggest that semiquan titative, online prefusion analysis with Acoustic Densitometry is as s ensitive as analysis offline with videodensitometry.