The measurement of tibial torsion by magnetic resonance imaging in children: the comparison of three different methods. 
There is no consensus about the measurement techniques to determine the tibial torsion by using MRI.  The primary research question of this study was to find out which MRI-based tibial torsion measurement method is more reliable and reproducible.  Secondly, we compared tibial torsion values measured by three measurement methods in T1- and T2-weighted images.  We retrospectively analyzed voluntary children performed MRI for determination of the lower limb torsional alignment after the surgical treatment between January 2013 and December 2013.  Thirty-four extremities of 17 patients were included in the present study.  The mean age of patients was 7.3 years (range 3-12 years).  The transmalleolar, posterior intermalleolar and anterior talus angles were used for the measurement of tibial torsion.  All tibial torsion measurements were calculated by three blinded observers in T1- and T2-weighted images, and these measurements were repeated blindly after 2 months.  All measured intra- and interobserver intra-class correlations were greater than 0.60.  The best scores were achieved with the anterior talus angle.  It was followed by the posterior malleolar angle and the intermalleolar angle, respectively.  Furthermore, there were no statistically significant differences between tibial torsion values measured by each observer in T1- and T2-weighted images of each method.  MRI-based tibial torsion measurements were reliable and reproducible for all three methods.  But we think that the anterior talus angle and the posterior malleolar angle are easier and more successful in determination of the tibial torsion.  Also, both T1- and T2-weighted images can be used successfully for this purpose.