中文摘要：

目的：评价三维CT扫描是否提高对AO分型B3型桡骨远端骨折的检出率。方法：选择2013年1月至2014年1月,北京积水潭医院创伤骨科急诊收治的30例桡骨远端骨折患者进行回顾性分析,所有患者均接受了切开复位内固定术,采集所有病例的原始X线片和三维CT扫描图像,由2名医师先根据X线片作出骨折的AO分型诊断,再根据三维CT扫描检查结果作出骨折AO分型诊断,将X线与三维CT扫描作出的诊断结果进行比较,评价X线和CT对B3骨折的检出率,并计算Cohen’s Kappa值判断X线片和CT对B3型骨折的诊断是否一致。结果：30例骨折病例经手术确认均为B3型桡骨远端骨折,10例术中确认为B3.3型骨折。三维CT检查结果的诊断与手术判断一致,而单纯依靠X线片只能诊断24例（24/30,80%）的B3型骨折,发现6例（6/10,60%）B3.3型骨折。CT扫描对B3型骨折的检出率优于X线（100%vs.80%,P〈0.05）,对B3.3型骨折的检出率也优于X线（100%vs.60%,P〈0.05）。CT扫描和X线检查对B3和B3.3型骨折诊断的一致性较差（kappa值=0）,最重要的是在此研究过程中发现并描述了两种特殊类型的B3型骨折,即桡侧B3型骨折和尺侧B3型骨折。结论：CT可以显著提高B3和B3.3桡骨远端骨折的诊断率,并有助于我们发现两种特殊类型的B3型骨折。

英文摘要：

Objective： To determine whether 3-dimentional CT scans is able to effectively improve the detection rate of AO B3 distal radius fractures in clinics. Methods： From Jan 2013 to Jan 2014,30 patients with distal radius fractures were retrospectively enrolled in this study,all the patients directly visited the skeletal trauma emergency department in Beijing Jishuitan Hospital post injury and all of them accepted open reduction and internal fixation of distal radius fractures at last. All the radiographic data including X ray films and 3-dimentional CT scans of these patients were collected. Two independent observers were required to make primary AO classifications for each fracture by X rays at first,then to make final AO classifications by 3-dimentional CT scans. Finally,the detection rates of CT scans and plain films for AO B3 distal radius fractures and B3. 3 distal radius fractures were compared,the agreements of the two methods for diagnosing AO B3 and B3. 3 fractures were calculated by Cohen＇s Kappa calculations.Results： All the 30 fractures were confirmed to be AO B3 distal radius fractures intraoperatively,and 10 of them were B3. 3 fractures. The results were completely consistent with the results of 3-dimensional CT scans. However,only 80%（24/30） AO B3 distal radius fractures and 60%（6/10） B3. 3 distal radius fractures could be diagnosed only by X rays. The detection rate of CT scans was proved to be significantly higher than X rays for diagnosing B3 distal radius fractures（100% vs. 80%,P 0. 05）,the detection rate of CT scans was also proved to be significantly higher than that of plain films for detecting B3. 3 distal radius fractures（100% vs. 60%,P 0. 05）. The agreement of 3-dimentional CT scans and X ray was poor for detecting both the AO B3 distal radius fracture and B3. 3 distal radius fracture（kappa = 0）.Most importantly,in the study process,two special kinds of B3 distal radius fracture were initially found and described by us. One was named as radial B3 fracture,and the ot