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作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　May 28, 2010 — 根據一項線上發表於5月26日放射學期刊的回溯性綜論結果，電腦斷層掃描（CT）結果陽性，且臨床發現非典型時，這些病患可能仍然需要接受闌尾切除術。
　　
　　來自舊金山加州大學的Joseph W. Stengel骨傷科醫學士與其同事們表示，臨床上懷疑罹患闌尾炎，且接下來接受CT診斷，但在外科醫師評估後未接受闌尾切除術的患者，仍然觀察到許多潛在偽陽性的結果。偶然的，我們經常遇到在外科評估後， CT檢查結果為急性闌尾炎典型表徵，但因為臨床表現不相符，因而延遲治療的病例。就我們所知，過去並沒有相關研究評估這一群患者。
　　
　　這項研究的目的在於確認CT檢查結果診斷為闌尾炎，但是臨床評估決定不進行手術的病患預後。
　　
　　試驗作者UCSF臨床放射醫學助理教授Emily M. Webb醫師在一篇新聞稿中表示，這些病患決定不進行手術通常造成未診斷出闌尾炎，增加了穿孔的風險。我們想要針對CT掃描陽性但非典型臨床症狀，且沒有立即切除闌尾的患者進行研究。
　　
　　在2002年到2007年之間，總共有2,283位病患因為懷疑闌尾炎，在UCSF醫學中心接受CT掃描。平均年齡為46歲（範圍從18-99歲），其中有856位男性、1,427位女性。根據回顧CT掃描報告，罹患闌尾炎可能性評分如下：1，確切沒有；2，看不到闌尾，且沒有發炎的次發性證據；3，結果不一；4，可能的，以及5，確切的。
　　
　　偽陽性CT掃描結果的定義是，CT報告被區分在可能的或確切的闌尾炎，但病患未在4天內接受闌尾切除。兩位不知道病患預後的判讀者，提供他們臨床數據，並前瞻性地判讀掃描結果，檢閱這些病例，並以相同的標準評分CT影像。然後以病歷檢閱以及描述性統計確認預後。
　　
　　516位病患（23%）CT檢查結果分數被分類為可能或確切闌尾炎，這些病患中，13位（3%）並未立即接受闌尾炎治療。在平均118天（範圍從5-443天）之間，這些病患中有5位（38%）接下來接受外科手術時發現有闌尾炎（95%信賴區間[CI]為18%-65%）。在平均後續追蹤583天（範圍從14-1460天），13位病患中有7位（54%）並沒有闌尾炎，而13位接受手術的病患中，有1位（8%）的闌尾是正常的。
　　
　　Webb醫師表示，其研究結果確認了CT掃描是診斷闌尾炎一個很好的診斷工具，且外科醫師在面對陽性CT檢查結果時應該謹慎。針對慢性或再發性闌尾炎做即時的治療，可以避免這些病患發生併發症或其他後續不好的副作用。
　　
　　這項研究的限制包括在第一次CT檢驗時缺乏闌尾炎病理學證據，少數CT檢驗陽性患者但是未接受外科或是保守治療、7位有顯然偽陽性CT檢驗結果但之後臨床症狀緩解病患沒有更長的臨床追蹤、還有可能的選擇性誤差。除此之外，因為CT報告由一位也參與之後影像審閱之判讀者可能的記憶誤差。
　　
　　研究作者們寫到，13位CT檢查發現有闌尾炎，但臨床評估結果令人放心，且因此延遲立即治療的病患中，有5位最終因為闌尾炎再度就診。CT檢查結果呈現有闌尾炎且臨床表徵是良性或非典型的患者，可能應該考慮慢性或再發性闌尾炎的診斷。
　　
　　試驗作者們表示沒有相關資金上的往來。


Appendectomy May Be Needed in Patients With Positive CT and Atypical Clinical Findings

By Laurie Barclay, MD
Medscape Medical News

May 28, 2010 — Appendectomy may be needed in patients with positive computed tomography (CT) and atypical clinical findings, according to the results of a retrospective review reported online May 26 in Radiology.

"An unknown number of potential false-positive results have been observed among patients in whom the clinical suspicion of appendicitis is raised and who subsequently receive a diagnosis of appendicitis at CT but do not undergo appendectomy after evaluation by a surgeon," write Joseph W. Stengel, DO, from the University of California, San Francisco (UCSF), and colleagues. "Occasionally, we have encountered such patients at CT with typical findings of acute appendicitis for whom treatment was deferred after surgical evaluation because of discordant clinical findings. To our knowledge, there are no prior studies in which this subgroup of patients has been evaluated."

The goal of the study was to determine the clinical outcome in patients who had CT findings diagnostic for appendicitis but in whom clinical evaluation resulted in the decision not to perform surgery.

"The decision to forego surgery in these patients often results in missed appendicitis, with a possible increased risk of perforation," said study coauthor Emily M. Webb, MD, UCSF assistant professor of clinical radiology, in a news release. "We wanted to look at patients with a positive CT scan but atypical clinical symptoms who did not have their appendix immediately removed."

Between 2002 and 2007, a total of 2283 patients at UCSF underwent CT examination for suspected appendicitis. Mean age was 46 years (age range, 18 - 99 years), and there were 856 men and 1427 women. On the basis of review of CT reports, the probability of appendicitis was scored as follows: 1, definitely absent; 2, nonvisualized appendix with no secondary evidence of inflammation; 3, equivocal; 4, probable; and 5, definitely present.

A false-positive CT result was defined as a CT report classified as probable or definite appendicitis in which the patient did not undergo surgery within 4 days. Two readers blinded to patient outcome, supporting clinical data, and prospective scan interpretation reviewed these cases and scored the CT images using the same scale. Outcomes were determined from medical records review and analyzed with use of descriptional statistics.

A CT result was scored as probable or definite appendicitis in 516 patients (23%), of whom 13 (3%) were not immediately treated for appendicitis. After a mean interval of 118 days (range, 5 - 443 days), 5 (38%) of these patients (95% confidence interval [CI], 18% - 65%) subsequently underwent appendectomy with findings of appendicitis at surgery. During a mean follow-up of 583 days (range, 14 - 1460 days), 7 (54%) of 13 patients never went on to have appendicitis, and 1 (8%) of 13 underwent surgery but had a normal appendix.

"The results of our study confirm that CT is a good diagnostic tool for appendicitis and that surgeons should be wary of dismissing positive CT findings," Dr. Webb said. "Prompt treatment of chronic or recurrent appendicitis can prevent patients from developing complications or other future ill effects."

Limitations of this study include lack of pathologic proof of appendicitis at the time of the first CT examination, small number of patients with positive CT results but deferred surgical or conservative treatment, lack of extended clinical follow-up in all 7 patients with apparent false-positive CT results and subsequent clinical resolution, and possible selection bias. In addition, there may have been recall bias because the CT reports were reviewed by 1 reader who also took part in the subsequent image review.

"Five of 13 patients with CT findings of appendicitis and reassuring clinical evaluation results in whom immediate treatment was deferred ultimately returned with appendicitis," the study authors write. "In patients with CT results positive for appendicitis and benign or atypical clinical findings, a diagnosis of chronic or recurrent appendicitis may be considered."

The study authors have disclosed no relevant financial relationships.

Radiology. Published online May 26, 2010.