Image Analysis, 1380 Burkesville Rd, Columbia, KY 42728, USA.
Int J Cardiovasc Imaging. 2012 Jun;28(5):1193-204. doi: 10.1007/s10554-011-9914-2. Epub 2011 Jun 25.
A negative (zero) Agatston coronary calcium score (CCS) by current methods confers a very low risk for hard coronary events during the next years. However, controversy remains on how to use a negative score since some hard events still occur. We report on a new method with improved detection sensitivity for very small calcifications with the potential to more confidently rule out early atherosclerotic disease. Seventy-eight (78) patients with negative Agatston scores by conventional methods with 2.5 mm slices were selected from routine GE 64 MDCT scans. Each scan was reconstructed a second time from the same data to create 0.625 mm isotropic voxels. The 2.5 mm images were manually scored by the usual Agatston method using the GE SmartScore™ software. Both the 2.5 and 0.625 mm image sets were scored with a new automated and calibrated method (N-vivo™, Image Analysis). The software automatically computes dual scoring thresholds that are statistically defined and specific for each patient, scanner, and scan. The images were hybrid calibrated by simultaneous scanned phantoms in combination with in vivo blood/muscle references. The output reported the calibrated mass scores along with the number of plaques using 18 pt, 3-D connectivity criteria. A CCS Test phantom with known CaHA microspheres was used to validate the method. Twenty-three percent (18 of 78) of the patients with negative Agatston scores by the conventional method scored positive for coronary calcifications by the N-vivo method. The number of small plaques scored per patient varied from 1 to 4. One patient with a single small calcification suffered a hard coronary event during the CT scan. All of the detected plaques were located in the proximal heart. The conventional CCS method misclassified 23% of these patients as having negative coronary calcium scores. The N-vivo automated scoring method with small voxel CT images increased the detection sensitivity of small calcifications with no increase in radiation dose. Detection of small coronary calcified plaques occult to conventional scoring methods may increase the negative predictive power of calcium scoring and may improve plaque composition analysis.
目前的方法得出的负（零）Agatston 冠状动脉钙评分（CCS）提示在接下来的几年中发生硬冠状动脉事件的风险非常低。然而，对于如何使用阴性评分仍存在争议，因为仍会发生一些硬事件。我们报告了一种新的方法，该方法对微小钙化具有更高的检测灵敏度，有可能更有信心地排除早期动脉粥样硬化疾病。从常规 GE 64 MDCT 扫描中选择了 78 名用传统方法得出阴性 Agatston 评分且层厚为 2.5mm 的患者。从相同的数据中对每个扫描进行第二次重建，以创建 0.625mm 各向同性体素。用 GE SmartScore™软件按常规的 Agatston 方法手动对 2.5mm 图像进行评分。用新的自动和校准方法（N-vivo™，图像分析）对 2.5mm 和 0.625mm 图像集进行评分。该软件自动计算针对每位患者、扫描仪和扫描统计定义和特定的双重评分阈值。通过同时扫描的体模与体内血液/肌肉参考相结合，对图像进行混合校准。报告的输出为使用 18 点、3-D 连通性标准的校准质量评分以及斑块数量。使用具有已知 CaHA 微球的 CCS 测试体模验证了该方法。用常规方法得出阴性 Agatston 评分的 78 名患者中有 23%（18 名）用 N-vivo 方法得出冠状动脉钙化呈阳性。每位患者的小斑块数量从 1 到 4 不等。一名患有单个小钙化的患者在 CT 扫描期间发生了硬冠状动脉事件。所有检测到的斑块均位于心脏近端。传统的 CCS 方法错误地将 23%的这些患者归类为冠状动脉钙评分阴性。使用小体素 CT 图像的 N-vivo 自动评分方法增加了对小钙化的检测灵敏度，而没有增加辐射剂量。对常规评分方法隐匿的小冠状动脉钙化斑块的检测可能会增加钙评分的阴性预测能力，并可能改善斑块成分分析。
