Department of Radiology, Erasmus University Medical Center, PO Box 2040, 3000 CA, Rotterdam, The Netherlands.
Skeletal Radiol. 2011 Jan;40(1):75-83. doi: 10.1007/s00256-010-0938-9. Epub 2010 Jun 13.
The optimal MRI scan planes of collateral ligaments of the ankle have been described extensively, with the exception of the syndesmotic ligaments. We assessed the optimal scan plane for depicting the distal tibiofibular syndesmosis.
In order to determine the optimal oblique caudal-cranial and lateral-medial MRI scan plane, two fresh frozen cadaveric ankles were used. The angle of the scan plane that demonstrated the anterior and posterior distal tibiofibular ligament uninterrupted in their full length was determined. In a prospective study this oblique scan plane was then used in addition to the axial and coronal planes, for MRI scans of both ankles in 21 healthy volunteers. Two observers independently evaluated the anterior tibiofibular ligament (ATIFL) and posterior tibiofibular ligament (PTIFL) regarding the continuity of the individual fascicles, thickness and wavy contour of the ligaments in both the axial and the oblique plane. Kappa was calculated to determine the interobserver agreement. McNemar's test was used to statistically quantify the significance of the two scan planes.
In the axial plane the ATIFL was in 31% (13/42) partly and in 69% (29/42) completely discontinuous; in the oblique plane the ATIFL was continuous in 88% (37/42) and partly discontinuous in 12% (5/42). Compared with the axial plane, the oblique plane demonstrated significantly less discontinuity (p<0.001), but not significantly less thickening (p=1.00) or less wavy contour (p=0.06) of the ATIFL. In the axial scan plane the PTIFL was continuous in 76% (32/42), partially discontinuous in 19% (8/42) and completely discontinuous in 5% (2/42); in the oblique plane the PTIFL was continuous in 100% (42/42). Compared with the axial plane, the oblique plane demonstrated significantly less discontinuity (p=0.002), but not significantly less thickening (p=1.00) or less wavy contour (p=0.50) of the PTIFL. The interobserver agreement score and kappa (κ) regarding the continuity for the ATIFL in the axial and oblique planes was 91% (κ=0.79) and 91% (κ=0.55) respectively; for the PTIFL it was 86% (κ=0.65) and 100% (κ = not defined).
The ATIFL and PTIFL are routinuely scanned in the orthogonal planes. The advantage of MRI scanning in an oblique image plane of about 45 degrees permits a better evaluation of the ligaments compared with the axial plane, particularly a better interpretation of ligament continuity, thickening and wavy contour. This may lead to a reduction in false-positive results, especially regarding partial or complete ligament ruptures. This can be of considerable aid in therapeutic management.
踝关节侧副韧带的最佳 MRI 扫描平面已有大量描述，但下胫腓联合韧带除外。我们评估了显示下胫腓联合远端的最佳扫描平面。
为了确定最佳斜尾-头和侧-内侧 MRI 扫描平面，我们使用了两个新鲜冷冻的尸体踝关节。确定显示完整全长的前、后下胫腓韧带的扫描平面的角度。在一项前瞻性研究中，除了轴位和冠状位外，我们还在 21 名健康志愿者的双侧踝关节中使用了这种斜位扫描平面。两位观察者分别评估了前胫腓韧带（ATIFL）和后胫腓韧带（PTIFL）在轴位和斜位上各个束的连续性、韧带的厚度和波浪状轮廓。使用 Kappa 计算来确定观察者间的一致性。使用 McNemar 检验来统计量化两种扫描平面的显著性。
在轴位上，ATIFL 部分连续性为 31%（13/42），完全连续性为 69%（29/42）；在斜位上，ATIFL 连续性为 88%（37/42），部分连续性为 12%（5/42）。与轴位相比，斜位显示的不连续性显著减少（p<0.001），但厚度（p=1.00）或波浪状轮廓（p=0.06）的变化不显著。在轴位扫描平面上，PTIFL 连续性为 76%（32/42），部分连续性为 19%（8/42），完全连续性为 5%（2/42）；在斜位上，PTIFL 连续性为 100%（42/42）。与轴位相比，斜位显示的不连续性显著减少（p=0.002），但厚度（p=1.00）或波浪状轮廓（p=0.50）的变化不显著。ATIFL 在轴位和斜位的观察者间一致性评分和 Kappa（κ）分别为 91%（κ=0.79）和 91%（κ=0.55）；PTIFL 分别为 86%（κ=0.65）和 100%（κ=未定义）。
ATIFL 和 PTIFL 通常在正交平面中扫描。与轴位相比，MRI 以约 45 度斜位扫描的优势在于可以更好地评估韧带，尤其是更好地解释韧带连续性、增厚和波浪状轮廓。这可能会减少假阳性结果，特别是关于部分或完全韧带撕裂的结果。这在治疗管理中可以提供很大的帮助。
