Cascade P N, Gross B H, Kazerooni E A, Quint L E, Francis I R, Strawderman M, Korobkin M
Department of Radiology, University of Michigan Hospitals, Ann Arbor 48109-0326, USA.
AJR Am J Roentgenol. 1998 Apr;170(4):927-31. doi: 10.2214/ajr.170.4.9530036.
Because CT protocols for staging lung cancer vary and little information exists regarding the diagnostic importance of using i.v. contrast material, our intent was to evaluate intra- and interobserver agreement in the detection of enlarged mediastinal lymph nodes, comparing i.v. contrast-enhanced and unenhanced CT.
Fifty patients with known or suspected bronchogenic carcinoma underwent unenhanced thoracic CT followed by contrast-enhanced CT. Three observers noted enlarged lymph nodes (> 10 mm in the short axis) and assigned the enlarged nodes to American Thoracic Society nodal station designations. Enlarged lymph nodes were grouped two ways: by assigning the exact number of enlarged lymph nodes found (zero, one, two, three, four or more), and by assigning whether at least one, or no, enlarged mediastinal lymph nodes were found at a station ("one or none"). Agreement levels were determined for inter- and intraobserver interpretations using weighted kappa statistics and the McNemar test.
The number of enlarged lymph nodes with enhanced CT was 11% higher than on unenhanced studies (418 versus 377; p = .044). Numbers of enlarged lymph nodes were different for five stations; however, the numbers were small except for the right upper paratracheal station (2R) (contrast-enhanced, 68 enlarged lymph nodes; unenhanced, 44 enlarged lymph nodes; p = .014). With regard to all stations together, intraobserver agreement between contrast-enhanced and unenhanced studies was almost perfect (kappa range, .85-.94), and no difference was found for any observer in the proportion of patients with at least one enlarged lymph node. Interobserver agreement was substantial or almost perfect for the total number of enlarged lymph nodes. For specific stations, the lowest kappa value was .48 at 2R. One observer reported more patients with at least one enlarged lymph node with contrast enhancement at station 2R (p = .031). Greater agreement existed between two observers at station 2R with contrast enhancement versus no enhancement (kappa = .85 versus .48; p = .02). Conclusions matched, and calculations of estimated kappa values gave similar results for determination of the specific number of enlarged lymph nodes at a station and the "one or none" category.
We found high agreement for intra- and interobserver interpretations for contrast-enhanced and unenhanced CT, although contrast-enhanced CT revealed more enlarged lymph nodes, especially at station 2R.
由于肺癌分期的CT方案各不相同，且关于静脉注射对比剂的诊断重要性的信息较少，我们旨在评估静脉注射对比剂增强CT和未增强CT在检测纵隔淋巴结肿大方面观察者间和观察者内的一致性。
50例已知或疑似支气管源性癌的患者先进行胸部未增强CT扫描，随后进行对比剂增强CT扫描。三位观察者记录肿大淋巴结（短轴>10mm），并将肿大淋巴结按照美国胸科学会淋巴结分区进行标注。肿大淋巴结按两种方式分组：按发现的肿大淋巴结的确切数量（零个、一个、两个、三个、四个或更多）分组，以及按某一分区是否发现至少一个或未发现肿大纵隔淋巴结（“一个或无”）分组。使用加权kappa统计量和McNemar检验确定观察者间和观察者内解读的一致性水平。
增强CT显示的肿大淋巴结数量比未增强扫描高11%（418个对377个；p = 0.044）。五个分区的肿大淋巴结数量不同；然而，除右上气管旁分区（2R）外数量都很少（增强扫描时68个肿大淋巴结；未增强扫描时44个肿大淋巴结；p = 0.014）。就所有分区而言，增强扫描和未增强扫描之间观察者内一致性几乎完美（kappa值范围为0.85 - 0.94），且任何观察者发现至少有一个肿大淋巴结的患者比例无差异。观察者间对肿大淋巴结总数的一致性为实质性或几乎完美。对于特定分区，2R分区的kappa值最低，为0.48。一位观察者报告在2R分区增强扫描时至少有一个肿大淋巴结的患者更多（p = 0.031）。在2R分区，两位观察者对增强扫描和未增强扫描结果的一致性更高（kappa值分别为0.85和0.48；p = 0.02）。结论一致，且计算估计的kappa值在确定某一分区肿大淋巴结的具体数量和“一个或无”类别时得出了相似结果。
我们发现增强CT和未增强CT在观察者间和观察者内解读方面具有高度一致性，尽管增强CT显示出更多肿大淋巴结，尤其是在2R分区。
