774-4 Echocardiographic Cardiac Rejection Surveillance Using Acoustic Densitometry of Two Dimensional Ultrasound Backscatter Imaging: Multiple Views and Regions of Interest

Abstract

On the hypothesis that cyclic variation of integrated backscatter (CV/IBS) could detect acute cardiac allograft rejection (REJ) independent of the echo view and location of the region of interest (ROI), CV/BS was measured in 54 cardiac transplant patients. IBS images were made in the long axis (LAX) and short axis views at papillary muscle level (SAX) using a 2.5 MHz transducer. Acoustic densitometry with on-line analysis was performed in 83 biopsy cases analyzing 6 ROls: septal (SEP), basal posterior (POST) and mid posterior wall (MID) in the LAX view and anterior (ANT), inferior (INF) and MID of the SAX views individually and in combination. Of 83 biopsies, 27 had mild REJ and 6 had moderate REJ. Significant differences in the magnitude of CV/IBS between non-REJ and both mild and moderate REJ were found at SEP and POST in the LAX view. Combining ROls in the LAX and/or the SAX views showed more significant discrimination of REJ. CV of IBS (dB) Individual ROI LONG AXIS (LAX) SHORT AXIS (LAX) SEP POST MID ANT INF MID non REJ 6.0 ± 1.4 6.6 ± 1.8 5.2 ± 1.4 5.8 ± 1.9 4.6 ± 1.4 5.5 ± 1.4 mild REJ 4.5 ± 1.3 ** 5.2 ± 1.6 † 4.5 ± 1.4 4.5 ± 1.3 † 3.8 ± 1.0 4.5 ± 1.3 † moderate REJ 3.9 ± l.4 † 4.3 ± 0.9 † 4.0 ± 1.3 4.5 ± 0.9 4.0 ± 0.8 4.6 ± 1.7 Combined ROls LAX LAX LAX–SEP + LAX-POST + (SEP + POST) (SEP + POST + MID) SAX–ANT SAX–MID non REJ 12.5 ± 2.7 17.7 ± 3.4 11.8 ± 2.6 12.1 ± 28 mild REJ 9.8 ± 2.6 ** 14.2 ± 3.6 ** 9.1 ± 2.2 ** 9.7 ± 2.7 ** moderate REJ 8.2 ± 2.3 ** 12.2 ± 3.4 ** 8.5 ± 2.1 † 8.8 ± 1.B * * p < 0.01 † p < 0.005 ** p < 0.001 vs. non-REJ These data indicate that the magnitude of CV/IBS is highly dependent upon the view and ROI location. Therefore careful selection of views and ROls is necessary for detection of REJ. The combination of CV/IBS from many ROls may be more sensitive for diagnosis of REJ than the measurement from any individual site.