Department of Diagnostic Radiology, Queen Elizabeth II Health Sciences Centre and Dalhousie University, 1276 S Park St, 3rd Fl, Halifax, NS B3H 2Y9, Canada.
Present address: Medical Imaging Department, King Abdulaziz Medical City, National Guard Health Affairs, Riyadh, Saudi Arabia.
AJR Am J Roentgenol. 2020 Sep;215(3):639-644. doi: 10.2214/AJR.19.22370. Epub 2020 May 14.
The objective of our study was to determine the accuracy of ultrasound (US) and CT in diagnosing appendicitis at our institution while taking into account the number of indeterminate examinations in accordance with the Standards for Reporting Diagnostic Accuracy (STARD) guidelines. We retrospectively evaluated 790 patients who underwent US, CT, or both for evaluation of suspected appendicitis between May 1, 2013, and April 30, 2015. Patient characteristics and US and CT examination results were recorded. The reference standard was histopathology or 3 months of medical record follow-up if surgery was not performed; 3 × 2 tables were generated, and sensitivity, specificity, overall test yield, and accuracy were calculated according to STARD guidelines. For surgical cases, time to surgery (one-way ANOVA) was compared among patients who underwent US alone, CT alone, or both US and CT. A total of 473 of 562 US examinations had indeterminate findings (overall test yield, 15.8%); sensitivity and specificity in the 89 diagnostic examinations were 98.5% and 54.2%, respectively. Thirteen of 522 CT examinations were indeterminate (overall test yield, 97.5%); sensitivity and specificity in the remaining 509 CT examinations were 98.9% and 97.2%, respectively. Taking indeterminate studies into account, the accuracy was 13.7% for US and 95.6% for CT. The negative appendectomy rates were 17.7% (11/62) for US and 3.3% (9/276) for CT ( = 0.0002). Time to surgery was longer for patients who underwent US and CT (mean ± SD, 17.7 ± 8.9 hours) than US alone (12.9 ± 6.4 hours; = 0.002) but was not longer for patients who underwent CT alone (16.3 ± 8.4 hours; = 0.45). At our institution, a large proportion of US examinations are indeterminate for appendicitis. CT is the preferred first-line imaging test for evaluating appendicitis in nonobstetric adult patients.
我们的研究目的是根据《诊断准确性报告标准》（STANDARD）指南，确定在我们机构中超声（US）和 CT 诊断阑尾炎的准确性，同时考虑到不确定检查的数量。我们回顾性评估了 2013 年 5 月 1 日至 2015 年 4 月 30 日期间因疑似阑尾炎接受 US、CT 或两者检查的 790 例患者。记录患者特征以及 US 和 CT 检查结果。参考标准为组织病理学或未行手术的 3 个月病历随访；根据 STANDARD 指南生成 3×2 表，并计算敏感性、特异性、总检测率和准确性。对于手术病例，比较仅行 US、仅行 CT 或 US 和 CT 均行的患者的手术时间（单向方差分析）。562 次 US 检查中共有 473 次检查结果不确定（总检测率为 15.8%）；89 次诊断性检查的敏感性和特异性分别为 98.5%和 54.2%。522 次 CT 检查中有 13 次结果不确定（总检测率为 97.5%）；其余 509 次 CT 检查的敏感性和特异性分别为 98.9%和 97.2%。考虑到不确定的研究结果，US 的准确性为 13.7%，CT 的准确性为 95.6%。US 的阴性阑尾切除率为 17.7%（11/62），CT 的阴性阑尾切除率为 3.3%（9/276）（=0.0002）。行 US 和 CT 的患者手术时间较长（平均±标准差，17.7±8.9 小时），比仅行 US 的患者（12.9±6.4 小时；=0.002）长，但比仅行 CT 的患者（16.3±8.4 小时；=0.45）短。在我们机构，很大一部分 US 检查对阑尾炎的结果不确定。CT 是评估非产科成年患者阑尾炎的首选一线影像学检查。
