Institute of Nuclear Medicine, University College London, University College Hospital, 235 Euston Road, London NW1 2BU, England, UK.
Division of Cardiovascular Medicine, Addenbrooke's Hospital, Box 110, ACCI, Hills Road, Cambridge CB2 2QQ, England, UK.
Atherosclerosis. 2014 Apr;233(2):510-517. doi: 10.1016/j.atherosclerosis.2014.01.001. Epub 2014 Jan 18.
There is a need for prognostic biomarkers for risk assessment of small abdominal aortic aneurysm (AAA). Since CT textural analysis of tissue is a recognized feature of adverse biology and patient outcome in other diseases, we investigated it as a possible biomarker in small AAA.
Fifty consecutive patients (46-men, 4-woman, median-age 75 y, range 56-85) with small AAA (3-5.5 cm) under surveillance undergoing serial ultrasound were prospectively recruited and assessed at baseline with CT texture analysis (CTTA) and 18F-Fluorodeoxyglucose positron emission tomography (18F-FDG-PET). We followed forty patients (36-men, 4-woman, median-age=74 y, range 60-85, participation rate=80% for 1 year. For each axial image, CTTA using the filtration-histogram technique was carried out using a software algorithm that selectively extracts texture features of different coarseness (fine, medium and coarse) and intensity variation. Standard-deviation (SD) and kurtosis (K) at each feature-scale were measured. The maximum standardized uptake value (SUVmax) of 18F-FDG in each axial image of the AAA was also measured with corrections for blood pool 18F-FDG activity to assess AAA metabolic activity. Specificity, sensitivity, and c-statistics were calculated with 95% confidence intervals for prediction of significant AAA expansion (≥2 mm) by CTTA measures before and after adjusting for clinical variables.
The median aneurysm expansion at 12 months was 2.0 mm, (IQR 0.0-4.0). Coarse texture SD correlated inversely with AAA SUVmax (rs=-0.456, P=0.003). Medium coarse texture K correlated significantly with future AAA expansion adjusted for baseline size (rs=0.343, P=0.030). AAA SUVmax correlated inversely with AAA expansion corrected for baseline size (rs=-0.383, P=0.015). Medium texture K was a strong predictor of significant AAA expansion (area under the Receiver-operating-characteristic (ROC) curve was 0.813) after adjusting for clinical variables.
We have shown evidence that CT signal heterogeneity measurements in small aortic aneurysm may be considered as a risk stratification tool in future prospective studies to identify aneurysms at risk of significant expansion. CT textural data appears to reflect AAA metabolism measured by PET.
需要寻找用于小腹部主动脉瘤（AAA）风险评估的预后生物标志物。由于组织的 CT 纹理分析是其他疾病中不良生物学和患者预后的公认特征，因此我们将其作为小 AAA 的一种可能的生物标志物进行了研究。
连续前瞻性招募了 50 名接受连续超声检查的小 AAA（3-5.5cm）患者（46 名男性，4 名女性，中位年龄 75 岁，范围 56-85 岁），并在基线时进行 CT 纹理分析（CTTA）和 18F-氟代脱氧葡萄糖正电子发射断层扫描（18F-FDG-PET）评估。我们随访了 40 名患者（36 名男性，4 名女性，中位年龄=74 岁，范围 60-85 岁，参与率=1 年时的 80%）。对于每个轴向图像，使用软件算法进行基于滤波-直方图技术的 CTTA，该算法选择性地提取不同粗糙度（细、中、粗）和强度变化的纹理特征。测量每个特征尺度的标准偏差（SD）和峰度（K）。还测量了 AAA 每个轴向图像中 18F-FDG 的最大标准化摄取量（SUVmax），并对血液池 18F-FDG 活性进行校正，以评估 AAA 的代谢活性。计算了 CTTA 测量值在调整临床变量前后对预测 AAA 显著扩张（≥2mm）的特异性、敏感性和 C 统计量，并计算了 95%置信区间。
12 个月时的中位动脉瘤扩张为 2.0mm（IQR 0.0-4.0）。粗糙纹理 SD 与 AAA SUVmax 呈负相关（rs=-0.456，P=0.003）。中等粗纹理 K 与调整后的基线大小的未来 AAA 扩张显著相关（rs=0.343，P=0.030）。校正基线大小后，AAA SUVmax 与 AAA 扩张呈负相关（rs=-0.383，P=0.015）。调整临床变量后，中等纹理 K 是 AAA 显著扩张的有力预测指标（受试者工作特征曲线下面积为 0.813）。
我们已经证明，在小主动脉瘤中，CT 信号异质性测量可以作为未来前瞻性研究中的风险分层工具，以识别有发生显著扩张风险的动脉瘤。CT 纹理数据似乎反映了通过 PET 测量的 AAA 代谢。
