Penticuff Ryan, Jeffrey R Brooke, Olcott Eric W
Department of Radiology, Stanford University School of Medicine, Stanford, California, USA.
Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA.
J Ultrasound Med. 2021 Feb;40(2):285-296. doi: 10.1002/jum.15399. Epub 2020 Jul 22.
To test the hypothesis that abutting and encasing types of hyperechoic periappendiceal fat are specific sonographic indicators of appendicitis in pediatric patients, including individuals with maximum outer diameters (MODs) of 6 to 8 mm in whom diagnosis by the MOD alone is known to be equivocal.
Appendiceal sonograms of 271 consecutive pediatric patients were retrospectively evaluated for hyperechoic periappendiceal fat (globular, ≥1.0 cm; categorized as type 0, none; type 1, "abutting," encompassing <180° of the appendiceal circumference; or type 2, "encasing," encompassing 180° or more of the appendiceal circumference) and the MOD. Histopathologic and medical records constituted reference standards. Statistical methods included the binomial distribution, logistic regression, a receiver operating characteristic analysis, and the exact McNemar test.
All patients with hyperechoic fat and 105 of 107 patients with appendicitis had MODs of 6 mm or greater. The MOD and fat types 1 and 2 each were significantly associated with appendicitis in the univariable regression. The MOD and fat type 1 were independently associated with appendicitis in multivariable regression (odds ratio, 24.97; P = .034; and odds ratio, 5.35; P < .001, respectively). Specificities of an MOD of 6 to 8 mm and an MOD of 6 mm or greater alone were 89.0% (95% confidence interval, 83.2%-93.4%); these increased to 100.0% each (95% confidence interval, 97.8%-100.0%; P < .001) when combined with fat types 1, 2, and either 1 or 2 as diagnostic criteria, with positive predictive values of 100.0%.
Types 1 and 2 periappendiceal fat are specific indicators of appendicitis, and both improve specificity compared to the MOD. Importantly, they add specificity in diagnosing appendicitis in patients with diagnostically equivocal MODs of 6 to 8 mm.
验证如下假设，即毗邻型和包绕型阑尾周围高回声脂肪是小儿阑尾炎的特异性超声指标，包括最大外径（MOD）为6至8毫米的个体，已知仅通过MOD诊断存在模棱两可的情况。
回顾性评估271例连续小儿患者的阑尾超声图像，观察阑尾周围高回声脂肪情况（球状，≥1.0厘米；分为0型，无；1型，“毗邻型”，包绕阑尾周长<180°；或2型，“包绕型”，包绕阑尾周长180°或更多）以及MOD。组织病理学和医疗记录作为参考标准。统计方法包括二项分布、逻辑回归、受试者工作特征分析和精确McNemar检验。
所有高回声脂肪患者以及107例阑尾炎患者中的105例MOD为6毫米或更大。在单变量回归中，MOD以及1型和2型脂肪均与阑尾炎显著相关。在多变量回归中，MOD和1型脂肪与阑尾炎独立相关（比值比分别为24.97；P = 0.034；以及比值比为5.35；P < 0.001）。单独的6至8毫米MOD以及6毫米或更大MOD的特异性分别为89.0%（95%置信区间，83.2% - 93.4%）；当与1型、2型脂肪以及1型或2型脂肪作为诊断标准联合使用时，特异性均提高到100.0%（95%置信区间，97.8% - 100.0%；P < 0.001），阳性预测值为100.0%。
1型和2型阑尾周围脂肪是阑尾炎的特异性指标，与MOD相比，二者均提高了特异性。重要的是，它们在诊断MOD为6至8毫米、诊断不明确的患者的阑尾炎时增加了特异性。
