Imaging in Acute Appendicitis: Lessons Learned from Appendicectomy Patients at Two District General Hospitals in the United Kingdom over a Six-year Period
OA Westerland, RK Singh, HC Nagraj, S Muthukumarasamy, K Ramesar, MP Saunders, DC Howlett
Hong Kong J Radiol 2016;19:118-25
DOI: 10.12809/hkjr1615353
Objective: To evaluate the utilisation and diagnostic accuracy of imaging for suspected appendicitis, in the context of the negative appendicectomy rate (NAR).
Methods: A database was compiled of patients who underwent appendicectomy for suspected appendicitis over a 6-year period at two district general hospitals in the United Kingdom. Data were collected about the imaging performed: abdominal radiograph (AXR), transabdominal ultrasound (TAUfS), transvaginal ultrasound (TVUS), or computed tomography of the abdomen and pelvis (CTAP). Results were compared with histology, and data analysed by sex in four age cohorts: 0-16, 17-30, 31-59, and ≥60 years.
Results: A total of 2017 patients (1023 female and 994 male) underwent appendicectomy. Overall, 759 (37.6%) patients underwent preoperative imaging (415 AXR, 348 TAUS, 88 TVUS, and 141 CTAP). TAUS use in females was 22.9%, 35.2%, 24.7%, and 15.9% in the 0-16, 17-30, 31-59, and ≥60 years age-groups, respectively. Respective TAUS use in men was 7.8%, 5.3%, 7.1%, and 9.2%. TAUS had a sensitivity of 72.3%, and positive predictive value (PPV) of 82.9%. CTAP use was 1.9%, 7.7%, and 32.4% in the <30, 31-59, and ≥60 years age-groups, respectively. CTAP had a sensitivity of 94.0%, and PPV of 90.4%. AXR and TVUS showed low sensitivity (6.2% and 21.8%, respectively). The overall NAR was 27.3%. The highest NAR was in women aged 17-30 years (42.8%), the lowest NAR was in women aged ≥60 years (12.4%) and boys (18.1%).
Conclusion: The NAR is higher in the current study in which use of imaging is less prevalent when compared with previously published studies. Our results suggest that imaging should be performed preoperatively. We recommend TAUS to be the first-line investigation in particular for patients aged <30 years. CT should be considered as an alternative for adults of all ages, in particular low-dose focused abdominal CT, which has been shown to have similar diagnostic performance in appendicitis compared to conventional CT.
中文摘要
急性闌尾炎成像：英國兩間分區醫院六年間經驗的分享
OA Westerland, RK Singh, HC Nagraj, S Muthukumarasamy, K Ramesar, MP Saunders, DC Howlett
目的：按陰性闌尾切除率（NAR）評估影像學對於懷疑闌尾炎個案的使用和診斷準確性。
方法：搜集並結合英國兩間分區醫院於6年期間，對懷疑闌尾炎個案作闌尾切除術的數據。收集有關影像學檢查，包括腹部平片（AXR）、腹部超聲（TAUS）、經陰道作超聲檢查（TVUS），以及腹部和骨盆的電腦斷層掃描（CTAP）。比較影像學檢查與組織學的結果，並分析性別和四個年齡組別的數據：0-16、17-30、31-59和60歲或以上。
結果：研究期間進行闌尾切除術共2017例（994名男性和1023名女性）。當中759人（37.6%）接受術前成像檢查：AXR415例、TAUS348例、TVUS88例、CTAP141例。0-16、17-30、31-59和60歲或以上女性的TAUS使用率依次為22.9%、35.2%、24.7%和15.9%；男性的相應TAUS使用率為7.8%、5.3%、7.1%和9.2%。TAUS的靈敏度為72.3%，陽性預測值為82.9%。CTAP在年齡組別<30、31-59和60歲或以上的使用率依次為1.9%、7.7%和32.4%。CTAP的靈敏度為94.0%，陽性預測值為90.4%。AXR和TVUS呈低靈敏度（分別為6.2%和21.8%）。總陰性闌尾切除率為27.3%。最高陰性闌尾切除率是17-30歲的女性（42.8%），最低陰性闌尾切除率是60歲或以上的女性（12.4%）和男孩（18.1%）。
結論：與文獻所記載的研究比較，我們使用影像學的次數不及其他機構，而本研究的陰性闌尾切除率較高。這研究的結果顯示應進行術前影像學檢查。我們建議使用TAUS作為一線檢測，特別是30歲以下的病人。對於成年病人，可考慮使用CT，尤其是低劑量腹部CT，因其與傳統CT診斷闌尾炎的表現相若。