Büber Nydia, Zanetti Marco, Frigg Arno, Saupe Nadja
Department of Musculoskeletal Radiology, Clinic Hirslanden, Zurich, Switzerland.
Centre for Foot and Ankle Surgery, Clinic Hirslanden, Zurich, Switzerland.
Skeletal Radiol. 2018 Jan;47(1):19-24. doi: 10.1007/s00256-017-2744-0. Epub 2017 Aug 10.
To compare the hindfoot alignment measured on standing HAV radiographs (Saltzman view) and on non-weight-bearing coronal MR images.
The apparent moment arm was measured on weight-bearing conventional radiographs (Saltzman views) and on MRIs of the ankle in 50 consecutive patients (mean age, 54 years; age range, 18-77 years). The evaluation was performed independently by three readers using analogous reference points for both methods. Positive values were assigned when the deepest point of the calcaneus was lateral to the tibial axis as valgus, negative values as varus. The intertechnique agreement and correlation for the measurements performed with HAV radiographs and MRI were assessed for each reader using the Bland-Altman method and the Pearson correlation coefficient, respectively. The interobserver agreement was assessed using the intraclass correlation coefficient.
The means of apparent moment arms, with the standard deviation (SD) in parentheses, of three readers were +2.0 (±8.4) mm, +1.5 (±6.6) mm and -1.4 (±8.2) mm on HAV radiographs and +4.6 (±7.4) mm, +6.3 (±5.3) mm and +5.4 (±6.4) mm on MRI. The Bland-Altman analysis found a systematic bias for all three readers, corresponding to an overestimation of measurements with MRI (systematic bias ranging from 2.6 to 4.8 mm). The intertechnique correlation was found moderate to high. The Pearson coefficients for the three readers were 0.75, 0.64 and 0.65. The interobserver agreement among the three readers was 0.72, 0.77 and 0.68 for HAV, MRI and both modalities together, respectively.
Hindfoot alignment can be estimated on MRI but the correlation between the values on HAV radiographs and MR images is only moderate with a tendency to increased positive values (valgization) on MR images.
比较站立位足拇外翻X线片（Saltzman位）和非负重冠状面磁共振成像（MRI）测量的后足对线情况。
对50例连续患者（平均年龄54岁；年龄范围18 - 77岁）的负重常规X线片（Saltzman位）和踝关节MRI测量其表观力臂。由三位阅片者分别使用两种方法的类似参考点进行独立评估。当跟骨最深点位于胫骨轴线外侧时为外翻，赋值为正值；位于内侧时为内翻，赋值为负值。分别采用Bland - Altman法和Pearson相关系数评估三位阅片者使用足拇外翻X线片和MRI测量结果的技术间一致性和相关性。采用组内相关系数评估观察者间一致性。
三位阅片者在足拇外翻X线片上的表观力臂均值（括号内为标准差）分别为+2.0（±8.4）mm、+1.5（±6.6）mm和 - 1.4（±8.2）mm，在MRI上分别为+4.6（±7.4）mm、+6.3（±5.3）mm和+5.4（±6.4）mm。Bland - Altman分析发现三位阅片者均存在系统偏差，对应于MRI测量值的高估（系统偏差范围为2.6至4.8 mm）。技术间相关性为中度至高度。三位阅片者的Pearson系数分别为0.75、0.64和0.65。三位阅片者在足拇外翻X线片、MRI以及两者联合测量时的观察者间一致性分别为0.72、0.77和0.68。
后足对线可通过MRI进行评估，但足拇外翻X线片和MRI测量值之间的相关性仅为中度，且MRI测量值有增加正值（外翻）的趋势。
