Gotteiner N L, Vonesh M J, Crawford S E, Burns W R, Duffy C E, Zales V R, McPherson D D
Department of Pediatrics and Pathology, Children's Memorial Hospital, Northwestern University Medical School, Chicago, IL 60614, USA.
J Heart Lung Transplant. 1996 Jun;15(6):596-604.
Ultrasonographic tissue characterization is the assessment of physical properties of biologic tissue on the basis of quantitative analysis of its acoustic characteristics. Abnormalities in microscopic structure that occur with cardiac allograft rejection may result in characteristic alterations in myocardial acoustics. Ultrasonographic tissue characterization may allow noninvasive detection of rejection.
Findings in 22 pediatric heart transplant patients undergoing routine surveillance for rejection by endomyocardial biopsy were prospectively evaluated. Off-line ultrasonographic tissue characterization analysis was done on transthoracic echocardiograms obtained at each biopsy. Within patients, tissue characterization texture measures derived from the ultrasonographic image data were compared with histologic findings. Univariate multiple regression analysis was used to identify texture measures associated with acute allograft rejection in a subgroup (n = 8) with at least one biopsy-proven episode of moderate rejection.
Measures of homogeneity (co-occurrence matrix correlation and heterogeneity (run-length nonuniformity) decreased with moderate rejection (p < 0.03). Homogeneity measures decreased if the patient had a previous episode of rejection. Several measures of heterogeneity (gray level difference and run-length statistics) were affected by the presence of edema. Run-length nonuniformity was the only measure that differentiated moderate rejection from edema. Discriminant analysis on all 22 patients correctly identified 96% of first rejection episodes (sensitivity 80%, specificity 64%), 93% of moderate and severe rejection episodes (sensitivity 71%; specificity 62%), and 69% of all rejection episodes (sensitivity 51%, specificity 91%).
Histologic changes associated with moderate and severe pediatric allograft rejection as reflected by characteristic alterations in myocardial acoustics can be assessed with ultrasonographic tissue characterization. Histologic changes associated with transplantation itself (resolution of rejection and edema) also affect myocardial acoustics and must be taken into account in rejection surveillance.
超声组织特征分析是基于对生物组织声学特性的定量分析来评估其物理特性。心脏同种异体移植排斥反应所导致的微观结构异常可能会引起心肌声学特性的特征性改变。超声组织特征分析或许能实现对排斥反应的无创检测。
对22例接受心肌内膜活检进行排斥反应常规监测的小儿心脏移植患者的检查结果进行前瞻性评估。对每次活检时获取的经胸超声心动图进行离线超声组织特征分析。在患者内部，将从超声图像数据得出的组织特征纹理测量值与组织学检查结果进行比较。使用单变量多元回归分析来确定在一个至少有一次经活检证实为中度排斥反应发作的亚组（n = 8）中与急性同种异体移植排斥反应相关的纹理测量值。
随着中度排斥反应的出现，均匀性测量值（共生矩阵相关性）降低，而异质性测量值（游程长度不均匀性）也降低（p < 0.03）。如果患者既往有排斥反应发作，则均匀性测量值会降低。几种异质性测量值（灰度级差异和游程长度统计量）受水肿存在的影响。游程长度不均匀性是唯一能区分中度排斥反应和水肿的测量值。对所有22例患者进行的判别分析正确识别出96%的首次排斥反应发作（敏感性80%，特异性64%）、93%的中度和重度排斥反应发作（敏感性71%；特异性62%）以及69%的所有排斥反应发作（敏感性51%，特异性91%）。
超声组织特征分析可评估与小儿同种异体移植中度和重度排斥反应相关的组织学变化，这些变化通过心肌声学特性的特征性改变得以体现。与移植本身相关的组织学变化（排斥反应和水肿的消退）也会影响心肌声学特性，在排斥反应监测中必须予以考虑。
