Gutfinger D E, Leung C Y, Hiro T, Maheswaran B, Nakamura S, Detrano R, Kang X, Tang W, Tobis J M
Division of Cardiology, University of California Irvine, Orange 92668, USA.
Am Heart J. 1996 May;131(5):899-906. doi: 10.1016/s0002-8703(96)90171-4.
The purpose of this investigation was to compare the accuracy of intravascular ultrasound (IVUS) and electron-beam computed tomography (EBCT) in quantitating human atherosclerotic plaque and calcium. In experiment 1, 12 human atherosclerotic arterial segments were obtained at autopsy and imaged by using IVUS and EBCT. The plaque from each arterial segment was dissected and a volume measurement of the dissected plaque was obtained by water displacement. The plaque from each arterial segment was ashed at 700 degrees F, and the weight of the remaining ashes was used as an estimate of the calcium mass. In experiment II, 11 calcified arterial segments were obtained at autopsy and imaged by using IVUS at one site along the artery. A corresponding histologic cross section stained with Masson's trichrome was prepared. In experiment I, the mean plaque volume measured by water displacement was 165.3 +/- 118.4 microliters. The mean plaque volume calculated by IVUS was 166.1 +/- 114.4 microliters and correlated closely with that by water displacement (r = 0.98, p < 0.0001). The mean calcium mass measured by ashing was 19.4 +/- 15.8 mg. The mean calculated calcium mass by EBCT was 19.9 mg and correlated closely with that by ashing (r=0.98, p<0.001). The mean calculated calcium volume by IVUS was 18.6 +/- 11.2 microliters and correlated linearly with the calcium mass by ashing (r = 0.87, p < 0.0003). In experiment II, the mean cross-sectional area of the calcified matrix was 1.71 +/- 0.66 mm2 by histologic examination compared with 1.44 +/- 0.66 mm2 by IVUS. There was a good correlation between the calcified cross-sectional area by histologic examination and IVUS (r = 0.76, p < 0.007); however, IVUS may underestimate the amount of calcium present depending on the intralesional calcium morphologic characteristics. In conclusion, IVUS accurately quantitates atherosclerotic plaque volume as well as the cross-sectional area and volume of intralesional calcium, especially if the calcium is localized at the base of the plaque. IVUS underestimates the amount of calcium present because of signal drop-off when the calcium is too thick for the ultrasound to completely penetrate. In comparison, EBCT accurately quantitates calcium mass regardless of the intralesional calcium morphologic characteristics; however, EBCT does not accurately quantitate plaque volume and will miss noncalcified atherosclerotic lesions.
本研究的目的是比较血管内超声（IVUS）和电子束计算机断层扫描（EBCT）在定量人体动脉粥样硬化斑块和钙含量方面的准确性。在实验1中，从尸检中获取12段人体动脉粥样硬化动脉节段，并使用IVUS和EBCT进行成像。将每个动脉节段的斑块进行解剖，并通过排水法获得解剖后斑块的体积测量值。将每个动脉节段的斑块在700华氏度下灰化，剩余灰烬的重量用作钙含量的估计值。在实验II中，从尸检中获取11段钙化动脉节段，并在动脉的一个部位使用IVUS进行成像。制备了用马松三色染色的相应组织学横截面。在实验I中，通过排水法测量的平均斑块体积为165.3±118.4微升。通过IVUS计算的平均斑块体积为166.1±114.4微升，与排水法测量值密切相关（r = 0.98，p < 0.0001）。通过灰化测量的平均钙含量为19.4±15.8毫克。通过EBCT计算的平均钙含量为19.9毫克，与灰化法测量值密切相关（r = 0.98，p < 0.001）。通过IVUS计算的平均钙体积为18.6±11.2微升，与灰化法测量的钙含量呈线性相关（r = 0.87，p < 0.0003）。在实验II中，组织学检查显示钙化基质的平均横截面积为1.71±0.66平方毫米，而IVUS测量值为1.44±0.66平方毫米。组织学检查和IVUS测量的钙化横截面积之间存在良好的相关性（r = 0.76，p < 0.007）；然而，根据病变内钙的形态学特征，IVUS可能会低估存在的钙含量。总之，IVUS能够准确地定量动脉粥样硬化斑块体积以及病变内钙的横截面积和体积，特别是当钙位于斑块底部时。当钙太厚以至于超声无法完全穿透时会出现信号衰减，导致IVUS低估存在的钙含量。相比之下，EBCT无论病变内钙的形态学特征如何都能准确地定量钙含量；然而，EBCT不能准确地定量斑块体积，并且会遗漏非钙化的动脉粥样硬化病变。
