Ciulla M, Paliotti R, Hess D B, Tjahja E, Campbell S E, Magrini F, Weber K T
Centro di Fisiologia Clinica e Ipertensione, Ospedale Maggiore, Università di Milano, Italy.
J Am Soc Echocardiogr. 1997 Jul-Aug;10(6):657-64. doi: 10.1016/s0894-7317(97)70028-2.
Echocardiographic image texture has been demonstrated to reflect the physical properties of the tissue under examination. To evaluate the role of collagen in determining the echo pattern of the left ventricular wall, we studied nine hypertensive patients with left ventricular hypertrophy (left ventricular mass index > 125 gm/m2) and biopsy-proven different degrees of myocardial fibrosis by analyzing the echocardiographic examinations performed before the biopsy. Myocardial tissue was sampled under fluoroscopy and two-dimensional echo guidance in the interventricular septum. Collagen volume fraction (CVF; normal range up to 2%) was taken as an index of fibrosis. The echo patterns were assessed by analyzing standard two-dimensional parasternal long-axis echocardiograms recorded on videotape. Images were color-coded at 256 levels (0 = yellow, 256 = black) and digitized off-line onto a personal computer. The region of analysis was set using a selection tool (20 x 10 mm) in the general area of septum where the specimen was taken. For each selection a color-level histogram, representing the frequency distribution, was derived with estimates of the average pixel intensity (mCS), skewness (SK), kurtosis (K), and the broad band (Bb) of the echoes about the distribution. Echo-derived parameters in each patient were compared with corresponding CVF values. CVF was out of range in all patients, ranging from 2.6% to 7.6% (mean 4.3% +/- 1.6%). No correlation was found between CVF and mCS, whereas a significant correlation was found at end diastole between CVF and the parameters describing histogram morphology, respectively, SK (r = 0.73), K (r = 0.69), Bb (r = 0.72). These findings for the first time demonstrate in vivo in hypertensive patients with left ventricular hypertrophy an agreement between echo amplitude and histologically assessed collagen volume. Thus in our studied patients collagen content appears to be the major determinant of regional echo intensity, its increase resulting in a significant and progressive wider asymmetrical left shift (yellow) of the color histogram.
超声心动图图像纹理已被证明能反映受检组织的物理特性。为评估胶原蛋白在决定左心室壁回声模式中的作用，我们研究了9例左心室肥厚（左心室质量指数>125 g/m²）且经活检证实有不同程度心肌纤维化的高血压患者，通过分析活检前进行的超声心动图检查。在荧光镜和二维超声引导下，于室间隔采集心肌组织样本。胶原容积分数（CVF；正常范围高达2%）作为纤维化指标。通过分析录像带上记录的标准二维胸骨旁长轴超声心动图来评估回声模式。图像以256级颜色编码（0 = 黄色，256 = 黑色）并离线数字化到个人电脑上。使用选择工具（20×10 mm）在采集样本的室间隔大致区域设置分析区域。对于每次选择，得出一个代表频率分布的颜色水平直方图，并估计平均像素强度（mCS）、偏度（SK）、峰度（K）以及回声关于该分布的宽带（Bb）。将每位患者的回声衍生参数与相应的CVF值进行比较。所有患者的CVF均超出范围，范围为2.6%至7.6%（平均4.3%±1.6%）。未发现CVF与mCS之间存在相关性，而在舒张末期发现CVF与描述直方图形态的参数之间分别存在显著相关性，即SK（r = 0.73）、K（r = 0.69）、Bb（r = 0.72）。这些发现首次在左心室肥厚的高血压患者体内证明了回声幅度与组织学评估的胶原容积之间的一致性。因此，在我们研究的患者中，胶原含量似乎是区域回声强度的主要决定因素，其增加导致颜色直方图出现显著且逐渐变宽的不对称左移（黄色）。
