Moshesh Malana, Peddada Shyamal D, Cooper Tracy, Baird Donna
Epidemiology Branch (M.M., D.B.) and Biostatistics Branch (S.D.P.), National Institute of Environmental Health, Research Triangle Park, North Carolina USA; and Department of Radiology, Division of Ultrasound, Henry Ford Health Systems, Detroit, Michigan USA (T.C.).
J Ultrasound Med. 2014 Jul;33(7):1217-24. doi: 10.7863/ultra.33.7.1217.
To evaluate intraobserver variability of fibroid sonographic measurements and apply this factor to fibroid growth assessment.
Study participants were African American women aged 23 to 34 years who had never had a diagnosis of uterine fibroids. All participants underwent transvaginal sonography to screen for the presence of previously undiagnosed fibroids (≥0.5 cm in diameter). The diameters of up to 6 fibroids were measured in 3 perpendicular planes at 3 separate times during the examinations by experienced sonographers. Intraobserver variability as measured by the coefficient of variation (CV) for fibroid diameter and volume was calculated for each fibroid, and factors associated with the CV were assessed by regression models. The impact of variability on growth assessment was determined.
Ninety-six of 300 women screened were found to have at least 1 fibroid, yielding a total of 174 fibroids for this analysis. The mean CV for the 3 measurements of fibroid maximum diameter was 5.9%. The mean CV for fibroid volume was 12.7%. Fibroid size contributed significantly to intraobserver variability (P = .04), with greater variability for smaller fibroids. Fibroid type (submucosal, intramural, or subserosal) was not important. Fibroids from the same woman tended to have similar measurement variability when assessed for volume but not for maximum diameter. Calculations showed that when following up fibroids, as much as a 20% increase in diameter could be due to measurement error, not "true growth."
A small fibroid must have a greater change in size than a large fibroid to conclude that it is growing, but even for small fibroids an increase in diameter of greater than 20% is likely to indicate true growth, not measurement variability.
评估子宫肌瘤超声测量的观察者内变异性，并将该因素应用于子宫肌瘤生长评估。
研究参与者为年龄在23至34岁之间、从未被诊断出患有子宫肌瘤的非裔美国女性。所有参与者均接受经阴道超声检查，以筛查先前未被诊断出的子宫肌瘤（直径≥0.5厘米）。在检查过程中，由经验丰富的超声检查人员在3个不同时间点，于3个相互垂直的平面上测量多达6个子宫肌瘤的直径。计算每个子宫肌瘤直径和体积的变异系数（CV）所衡量的观察者内变异性，并通过回归模型评估与CV相关的因素。确定变异性对生长评估的影响。
在300名接受筛查的女性中，有96人被发现至少有1个子宫肌瘤，本次分析共纳入174个子宫肌瘤。子宫肌瘤最大直径3次测量的平均CV为5.9%。子宫肌瘤体积的平均CV为12.7%。肌瘤大小对观察者内变异性有显著影响（P = .04），较小的肌瘤变异性更大。肌瘤类型（黏膜下、肌壁间或浆膜下）并不重要。对同一女性的肌瘤进行体积评估时，其测量变异性往往相似，但最大直径的变异性并非如此。计算结果表明，在随访子宫肌瘤时，直径增加多达20%可能是由于测量误差，而非“真正的生长”。
小肌瘤的大小变化必须大于大肌瘤才能判定其在生长，但即使是小肌瘤，直径增加超过20%也可能表明是真正的生长，而非测量变异性。
