Weyant M J, Eachempati S R, Maluccio M A, Rivadeneira D E, Grobmyer S R, Hydo L J, Barie P S
Department of Surgery, The New York-Presbyterian Hospital and Weill Medical College of Cornell University, New York, NY 10021, USA.
Surgery. 2000 Aug;128(2):145-52. doi: 10.1067/msy.2000.107422.
Computed tomography (CT) is used increasingly to diagnose acute appendicitis, despite variable technique and interpretation. We hypothesized that CT interpretation would not reflect actual clinical-pathologic findings in all demographic patient groups.
A prospective university hospital database of 625 consecutive patients (1995-1999), all of whom were operated on for appendicitis (261, or 41.8%, within 24 hours of discretionary CT), was reviewed. CT and pathology data were obtained from final, written reports. CT criteria included free fluid or air, appendiceal visualization, mesenteric fat stranding, and blurred pericecal fat. Appendix pathology included acute, gangrenous, and perforated organs. Statistics were performed with the Fisher exact test (coordinate data) and univariate analysis of variance (continuous data); multivariate analysis of variance for independent effects on dependent variable (positive CT or pathology; P <.05).
The mean age was 35 +/- 1 years with 46.6% being female patients. CT was done more often in women and after 1997 (both P <.05). The sensitivity and specificity of CT were 96.1% and 16.1%, respectively. The positive predictive value (PPV) and accuracy rate (A) were 90%, and 88%, respectively. After CT, the incidence of finding a normal appendix was lower (19.3% vs 12.3%, P <.05), especially if the white blood cell count (WBC) was normal (< or = 11K/microL, 6.1% vs 23.2%, P <.001). If the WBC was < or = 11K/microL with positive CT, PPV/A was 73. 7%/71.3%, whereas with WBC > 11K/microL and positive CT, PPV/A was 99.4%/93.3%. Multivariate analysis of variance showed that none of the individual variables used by the radiologist to determine a positive CT scan correlated with outcome determined by surgical pathology. A healthy appendix was predicted by a CT interpreted as negative and younger age (both P <.05), and especially by lower WBC (P <.0001), but not by gender or surgeon.
Although the negative appendectomy rate was decreased by CT, there was no correlation between CT findings and pathologically proved disease. Other factors such as more precise patient selection by clinical criteria may also be improving outcome. A positive CT scan in a patient with a normal WBC should be interpreted with caution.
尽管计算机断层扫描（CT）技术和解读存在差异，但它在急性阑尾炎诊断中的应用越来越广泛。我们推测，CT解读结果在所有不同人口统计学特征的患者群体中，并不能反映实际的临床病理表现。
回顾了一所大学医院的前瞻性数据库，该数据库包含625例连续患者（1995 - 1999年），所有患者均因阑尾炎接受手术治疗（其中261例，即41.8%，在可自由选择CT检查后的24小时内进行了CT检查）。CT和病理数据来自最终的书面报告。CT标准包括腹腔内游离液体或气体、阑尾显影、肠系膜脂肪条索状改变以及阑尾周围脂肪模糊。阑尾病理包括急性、坏疽性和穿孔性病变。采用Fisher精确检验（分类数据）和单因素方差分析（连续数据）进行统计学分析；对影响因变量（CT阳性或病理阳性；P <.05）的独立效应进行多因素方差分析。
患者平均年龄为35 ± 1岁，女性患者占46.6%。女性患者及1997年以后进行CT检查的患者更多（P均<.05）。CT的敏感性和特异性分别为96.1%和16.1%。阳性预测值（PPV）和准确率（A）分别为90%和88%。CT检查后，发现阑尾正常的发生率较低（19.3%对12.3%，P <.05），尤其是白细胞计数（WBC）正常（≤11K/μL）的患者（6.1%对23.2%，P <.001）。如果WBC≤11K/μL且CT阳性，PPV/A为73.7%/71.3%；而WBC > 11K/μL且CT阳性时，PPV/A为99.4%/93.3%。多因素方差分析显示，放射科医生用于判断CT扫描阳性的各个变量，均与手术病理确定的结果无关。CT解读为阴性且年龄较小的患者，阑尾正常的预测概率较高（P均<.05），尤其是WBC较低时（P <.0001），但与性别或外科医生无关。
尽管CT降低了阴性阑尾切除率，但CT表现与病理证实的疾病之间并无相关性。其他因素，如通过临床标准更精确地选择患者，可能也在改善治疗结果。对于WBC正常的患者，CT扫描阳性结果应谨慎解读。
