Cardiac Imaging, University Hospital Zurich, Ramistrasse 100, CH-8091 Zurich, Switzerland.
Acad Radiol. 2010 Feb;17(2):201-6. doi: 10.1016/j.acra.2009.09.007. Epub 2009 Nov 26.
To determine the impact of additional coronary calcium scoring on total effective radiation dose and diagnostic accuracy of low-dose computed tomography coronary angiography (CTCA) with prospective electrocardiogram (ECG) triggering.
Sixty-one consecutive patients underwent 64-slice CTCA using prospective ECG triggering, calcium scoring, and invasive quantitative coronary angiography, the latter served as standard of reference. Diagnostic accuracy was calculated for CTCA, calcium scoring, and for the combination of both. Receiver operator characteristic analyses were performed to determine cutoffs for prediction of significant coronary artery stenoses.
Mean effective radiation dose was 2.1 + or - 0.7 mSv (range, 1.0-3.3 mSv) for CTCA and 1.1 + or - 0.1 mSv (range, 0.9-1.4 mSv) for calcium scoring. Per-patient sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 85.7%, 89.2%, and 100% for CTCA, and 72.7%, 82.1%, 82.8%, and 71.9% for calcium scoring. Adding calcium-scoring with a cutoff at 133 in patients aged >50.7 years with nondiagnostic CTCA improved the respective values of diagnostic accuracy of the entire study population to 100%, 96.4%, 97.1%, and 100%; the added value of calcium scoring was confined to only three patients (5%), who were reclassified from false positive to true negative.
Specificity and PPV of low-dose CTCA may be further improved by combining it with coronary calcium scoring. However, only a fraction of patient may benefit, whereas exposing the entire population to more than 50% increase in effective radiation dose.
确定在使用前瞻性心电图（ECG）触发的低剂量计算机断层扫描冠状动脉成像（CTCA）中，额外进行冠状动脉钙评分对总有效辐射剂量和诊断准确性的影响。
61 例连续患者接受了 64 层 CTCA 检查，使用前瞻性 ECG 触发、钙评分和有创定量冠状动脉造影，后者作为标准参考。计算了 CTCA、钙评分和两者结合的诊断准确性。进行了受试者工作特征分析，以确定预测显著冠状动脉狭窄的截断值。
CTCA 的平均有效辐射剂量为 2.1 ± 0.7 mSv（范围，1.0-3.3 mSv），钙评分的平均有效辐射剂量为 1.1 ± 0.1 mSv（范围，0.9-1.4 mSv）。CTCA 的每位患者的敏感性、特异性、阳性预测值和阴性预测值分别为 100%、85.7%、89.2%和 100%，钙评分分别为 72.7%、82.1%、82.8%和 71.9%。在年龄>50.7 岁、CTCA 结果不可诊断的患者中，将钙评分的截断值设为 133，并添加钙评分，可将整个研究人群的诊断准确性的各自值提高到 100%、96.4%、97.1%和 100%；钙评分的附加价值仅限于仅三名患者（5%），他们从假阳性重新分类为真阴性。
通过将低剂量 CTCA 与冠状动脉钙评分相结合，可以进一步提高特异性和阳性预测值。然而，只有一部分患者可能受益，而使整个人群的有效辐射剂量增加超过 50%。
