The clinical value of ultrasonic tissue characterization in the management of heart transplant patients

Abstract

The purpose of this study was to evaluate the rejection process by ultrasonic tissue characterization. Serial 2D echocardiographic images were obtained within 24 h prior to an endomyocardial biopsy. The end-diastolic echoframes were digitized into a computer matrix. A region of interest was placed into the anteroseptal segment of each scan. Image texture was analysed by four major groups of texture analysis (first-order histogram, co-occurrence matrix, run-length statistic, power spectrum). In 23 patients, 408 biopsies were taken after each examination, so that correlation between the ultrasonic tissue measurements and the histological state of the tissue could be determined. When rejection occurred, heterogeneity, brightness and contrast of texture increased. Of 117 texture parameters originally claculated, three parameters (inverse difference moment, run-length non-uniformity, ring sums of power spectrum) that characterized rejection were determined by means of discriminance analysis. Compared with biopsy findings, echocardiographic sensitivity for moderate rejection was 93.3% and specifity 83.6%. Our study indicates that acute rejection is associated with changes in echocardiographic texture. Serial echocardiographic texture analysis can reliably identify heart transplant rejection.