Gangadhar Kiran, Hippe Daniel S, Thiel Jeff, Dighe Manjiri
Body Imaging Section, University of Washington, Seattle, Washington USA
Department of Radiology, University of Washington, Seattle, Washington USA.
J Ultrasound Med. 2016 Aug;35(8):1661-7. doi: 10.7863/ultra.15.10016. Epub 2016 Jun 22.
To assess the effect of orientation on the stiffness measurement by shear wave elastography (SWE) within a thyroid nodule.
Forty-five patients with 50 thyroid nodules were enrolled in this study. After a short sonographic examination, SWE images were acquired in transverse and longitudinal orientations. Multiple elastograms of each nodule were obtained in both orientations. Mean and maximum stiffness values were recorded from each region of interest. The overall mean and maximum stiffness values of each nodule were calculated for both orientations separately. The concordance correlation coefficient was used to assess overall agreement between measurements. A receiver operating characteristic curve analysis was conducted to assess diagnostic performance for benign versus malignant nodules.
The 45 patients included 6 men and 39 women (mean age, 53 years; range, 23-84 years). The mean stiffness values ± SD were 19.1 ± 18.4 and 20.9 ± 21.5 kPa for transverse and longitudinal measurements, respectively, with a small overall bias between the orientations (1.8 kPa; P = .09). Overall agreement was good (concordance correlation coefficient, 0.93) although moderated somewhat after the stiffness values were log transformed to reduce skewness (concordance correlation coefficient, 0.76). Of the 50 nodules, 6 were classified as malignant. The area under the curve based on the mean stiffness value from longitudinal images tended to be better than for transverse images, but the difference was not statistically significant (0.93 versus 0.83; P = .17).
Our study has shown that good diagnostic performance can be achieved by using SWE in longitudinal and transverse orientations. Moderate to good agreement in mean and maximum stiffness values for both orientations was observed, with only a small bias. Diagnostic performance for benign and malignant nodules was similar. The similar performance of both orientations gives flexibility in imaging patients with anatomic or physical limitations.
评估甲状腺结节内取向对剪切波弹性成像（SWE）测量硬度的影响。
本研究纳入了45例患有50个甲状腺结节的患者。经过简短的超声检查后，在横向和纵向取向获取SWE图像。在两个取向中均获得每个结节的多个弹性图。从每个感兴趣区域记录平均和最大硬度值。分别计算每个结节在两个取向中的总体平均和最大硬度值。一致性相关系数用于评估测量之间的总体一致性。进行受试者工作特征曲线分析以评估良性与恶性结节的诊断性能。
45例患者包括6名男性和39名女性（平均年龄53岁；范围23 - 84岁）。横向和纵向测量的平均硬度值±标准差分别为19.1±18.4 kPa和20.9±21.5 kPa，两个取向之间总体偏差较小（1.8 kPa；P = 0.09）。总体一致性良好（一致性相关系数，0.93），尽管在对硬度值进行对数转换以减少偏度后一致性有所降低（一致性相关系数，0.76）。在50个结节中，6个被分类为恶性。基于纵向图像平均硬度值的曲线下面积倾向于优于横向图像，但差异无统计学意义（0.93对0.83；P = 0.17）。
我们的研究表明，在纵向和横向取向使用SWE均可实现良好的诊断性能。观察到两个取向的平均和最大硬度值具有中度至良好的一致性，仅有较小偏差。良性和恶性结节的诊断性能相似。两个取向的相似性能为解剖或身体有局限的患者成像提供了灵活性。
