Scott D S, Arora U K, Farb A, Virmani R, Weissman N J
Division of Cardiology, Georgetown University Medical Center, Washington, DC, USA.
Am J Cardiol. 2000 Jan 1;85(1):37-40. doi: 10.1016/s0002-9149(99)00603-7.
Current methods of calcium quantification by intravascular ultrasound (IVUS) measure the arc of calcium using the cross-sectional image at the lesion and at the reference site while neglecting calcium elsewhere. Calcium at these sites may not adequately represent the extent of total epicardial coronary calcium. We devised a new method to quantify calcium as a percentage of the coronary luminal surface. This study examines whether this new method accurately reflects coronary calcium determined by histology. Seventeen postmortem coronary arteries were pressure-fixed and imaged by IVUS using a motorized pullback device. Total plaque-luminal circumferential length and calcified plaque-luminal circumferential length were measured from serial cross-sectional IVUS images every 1 mm. With use of Simpson's method, the total plaque and calcified plaque surface area was then calculated. Histologic sections were stained with hematoxylin-eosin and Movat pentachrome at 3-mm intervals. Calcium was independently quantified by planimetry under light microscopy. Histologic analysis (n = 253 sections) revealed a wide range of calcium (0 to 47 mm2; mean 12 +/- 16 mm3). The IVUS-derived calcified plaque surface area was 17 +/- 23 mm2), which represented 3.1 +/- 4.1% (range 0% to 13.9%) of the total plaque surface area. The histologic and IVUS quantification of calcium by this method was strongly related (r = 0.84, p <0.0001), which was an improvement over current 2-dimensional measures of calcium arc (r = 0.41, p = 0.18). Calculation of calcified plaque surface area from sequential IVUS images appears to accurately reflect the degree of total coronary calcification.
目前通过血管内超声（IVUS）进行钙定量的方法，是利用病变处和参考部位的横截面图像来测量钙弧，而忽略了其他部位的钙。这些部位的钙可能无法充分代表冠状动脉心外膜总钙的范围。我们设计了一种新的方法，将钙定量为冠状动脉腔表面的百分比。本研究旨在检验这种新方法是否能准确反映由组织学确定的冠状动脉钙。17例死后冠状动脉经压力固定，使用电动回撤装置通过IVUS成像。从每隔1毫米的连续IVUS横截面图像中测量总斑块-腔圆周长度和钙化斑块-腔圆周长度。然后使用辛普森方法计算总斑块和钙化斑块表面积。组织学切片每隔3毫米用苏木精-伊红和Movat五色染色。在光学显微镜下通过平面测量法独立对钙进行定量。组织学分析（n = 253个切片）显示钙的范围很广（0至47平方毫米；平均12±16立方毫米）。IVUS得出的钙化斑块表面积为17±23平方毫米，占总斑块表面积的3.1±4.1%（范围0%至13.9%）。通过这种方法对钙进行的组织学和IVUS定量密切相关（r = 0.84，p <0.0001），这比目前的二维钙弧测量方法有所改进（r = 0.41，p = 0.18）。从连续IVUS图像计算钙化斑块表面积似乎能准确反映冠状动脉钙化的程度。
