Barreto Mitya, Schoenhagen Paul, Nair Anuja, Amatangelo Stacy, Milite Margherita, Obuchowski Nancy A, Lieber Michael L, Halliburton Sandra S
Imaging Institute, Cardiovascular Imaging Lab, Cleveland Clinic, Cleveland, OH 44195, USA.
J Cardiovasc Comput Tomogr. 2008 Jul-Aug;2(4):234-42. doi: 10.1016/j.jcct.2008.05.146. Epub 2008 Jun 12.
Noninvasive characterization of coronary atherosclerotic plaque is limited with current computed tomography (CT) techniques. Dual-energy CT (DECT) has the potential to provide additional attenuation data for better differentiation of plaque components.
We attempted to characterize coronary atherosclerotic plaque with DECT.
Seven human coronary arteries acquired at autopsy were scanned consecutively at 80 and 140 kVp with CT. Vessels were perfused with saline, and data were acquired before and after contrast agent injection. Lesions were identified, and attenuation measurements were made from CT image quadrants. CT quadrants were classified as densely calcified, fibrocalcific, fibrous, lipid-rich, or normal vessel wall, corresponding to matched histology images. Attenuation values at each peak tube voltage were compared within plaque types for both noncontrast and contrast scans. Further, dual-energy index (DEI) values computed from attenuation were analyzed for classification of plaque.
In 14 lesions, a total of 56 quadrants were identified. Histology results classified 8 (14%) as densely calcified, 8 (14%) as fibrocalcific, 9 (16%) as fibrous, 5 (9%) as lipid-rich, and 25 (45%) as normal vessel wall. Calcified lesions attenuated significantly more at 80 kVp in both contrast and noncontrast scans, whereas fibrous plaque attenuated more at 80 kVp only for contrast-enhanced scans. No differences were found for lipid-rich plaques. Using DEI values, only densely calcified plaques could be distinguished from other plaque types except fibrocalcific plaques in contrast images.
Only densely calcified and fibrocalcific plaques showed a true change in attenuation at 80 versus 140 kVp. Therefore, calcified plaques could be distinguished from noncalcified plaques with DECT, but further classification of plaque types was not possible.
目前的计算机断层扫描（CT）技术在冠状动脉粥样硬化斑块的无创特征分析方面存在局限性。双能量CT（DECT）有潜力提供额外的衰减数据，以更好地区分斑块成分。
我们尝试用DECT对冠状动脉粥样硬化斑块进行特征分析。
对7例尸检获得的人类冠状动脉在80 kVp和140 kVp下进行CT连续扫描。血管用生理盐水灌注，并在注射造影剂前后采集数据。识别病变，并从CT图像象限进行衰减测量。CT象限被分类为致密钙化、纤维钙化、纤维、富含脂质或正常血管壁，对应匹配的组织学图像。对非增强和增强扫描的每种斑块类型，比较每个峰值管电压下的衰减值。此外，分析从衰减计算得到的双能量指数（DEI）值以进行斑块分类。
在14个病变中，共识别出56个象限。组织学结果将8个（14%）分类为致密钙化，8个（14%）为纤维钙化，9个（16%）为纤维，5个（9%）为富含脂质，25个（45%）为正常血管壁。在增强和非增强扫描中，钙化病变在80 kVp时的衰减均显著更高，而纤维斑块仅在增强扫描时在80 kVp时衰减更高。富含脂质的斑块未发现差异。使用DEI值，在增强图像中，只有致密钙化斑块可与除纤维钙化斑块外的其他斑块类型区分开来。
只有致密钙化和纤维钙化斑块在80 kVp与140 kVp时显示出真正的衰减变化。因此，钙化斑块可通过DECT与非钙化斑块区分开来，但无法进一步对斑块类型进行分类。
