A MRI study on talar cartilage injury with small field of view coil and BLADE sequence under ankle traction / 中华放射学杂志

ABSTRACT

Objective:To evaluate the application values of small FOV surface coil and BLADE sequence in MR imaging on assessment of talar cartilage injury of ankle joint under traction.Methods:The clinical and imaging data of 53 patients with ankle cartilage injury in the Affiliated Suzhou Hospital of Nanjing Medical University from December 2018 to July 2020 were prospectively analyzed. All patients underwent the following MR sequences sequence Ⅰ was fast spin echo proton density weighted (FSE-PD) BLADE sequence with surface coil small FOV, and sequence Ⅱ was FSE-PD-BLADE imaging of small FOV under horizontal load traction of ankle joint. Paired sample Wilcoxon rank sum test was used to compare the thickness of talus dome cartilage, cartilage space and subjective assessment score of image quality (including the outline of the upper surface of the cartilage at the injury, the thickness of the cartilage layer at the injury, the rupture of the cartilage at the injury, the relationship between cartilage and subchondral bone, subchondral bone collapse or trabecular fracture line) between sequence I and sequence Ⅱ.Results:There was significant difference in the thickness of central cartilage of talus between sequence Ⅰ and sequence Ⅱ [0.70 (0.60, 0.90) mm and 0.80 (0.70, 0.90) mm, Z=-2.900, P=0.004, respectively]. There was no significant difference in the thickness of medial and lateral talus cartilage between sequence Ⅰ and sequence Ⅱ (P>0.05). There were significant differences between sequence Ⅰ and sequence Ⅱ in the center [0.10 (0, 0.15), 0.89(0.63, 1.00) mm], medial [0.10(0, 0.31), 1.20(0.70, 1.25) mm] and lateral cartilage space [0.18(0.08, 0.23), 0.90(0.76, 0.94)mm] (all P<0.001). As for the subjective assessment score of talus cartilage injury, except for score in subchondral bone collapse or bone trabecular fracture line between sequence Ⅱ and sequence Ⅰ ( Z=-1.480, P=0.139), significant differences were found in all other scores ( P<0.05). Conclusion:MRI of the ankle under traction is safe and feasible. Under the condition of horizontal traction, small FOV surface coil combined with BLADE sequence can better display talus cartilage injury.