Baunin C, Sanmartin-Viron D, Accadbled F, Sans N, Vial J, Labarre D, Domenech C, Sales de Gauzy J
Department of Paediatric Imaging, hôpital des Enfants, CHU de Toulouse, 31059 Toulouse, France.
Department of Paediatric Orthopaedic Surgery, hôpital des Enfants, CHU de Toulouse, 31059 Toulouse, France.
Orthop Traumatol Surg Res. 2014 May;100(3):317-21. doi: 10.1016/j.otsr.2013.12.025. Epub 2014 Apr 13.
To evaluate diffusion MRI of the proximal femoral epiphysis and metaphysis as a prognosis factor in Legg Calvé Perthes (LCP) disease.
Thirty-one children (mean age 5.5 years, range 2.5-10.5) with unilateral LCP were included in a prospective, consecutive series. Radiographs were analysed and classified as per Herring criteriae. Mean follow-up was 19 months (range 6-30). Forty-nine MRI scans were performed at either the condensation or fragmentation stage. Apparent Diffusion Coefficient (ADC) of both the femoral epiphysis and metaphysis were measured bilaterally and ADC ratio were calculated, then compared to the Herring group.
Sixteen hips were rated Herring A or B, 3 Herring B-C and 12 Herring C. ADC was increased in affected hips compared to unaffected sides, both at the femoral epiphysis (P<0.001) and metaphysis (P<0.0001). ADC ratio of the femoral metaphysis was positively correlated to Herring classification: if superior to 1.63, it was associated with a bad prognosis (Herring B-C or C) (P=0.0017, sensitivity=89%, specificity=58%). Interobserver reliability of ADC measurement was excellent. The 1.63 threshold could be determined as early as the condensation stage.
Diffusion presents several advantages including being non radiating and non invasive. It does not need contrast medium administration and it can be performed without anaesthesia. The origin of the increased ADC remains unknown. Basically, it reflects molecular changes (true diffusion) but it is also influenced by the vascular supply (pseudo-diffusion). ADC ratio could provide an early prognosis before Herring classification is applicable.
Level III. Prospective uncontrolled study.
评估股骨近端骨骺和干骺端的扩散加权磁共振成像（MRI）作为Legg-Calvé-Perthes（LCP）病预后因素的价值。
31例单侧LCP患儿（平均年龄5.5岁，范围2.5 - 10.5岁）纳入一项前瞻性连续研究。根据Herring标准分析X线片并进行分类。平均随访19个月（范围6 - 30个月）。在骨软骨炎的凝固期或碎裂期进行了49次MRI扫描。双侧测量股骨骨骺和干骺端的表观扩散系数（ADC），计算ADC比值，并与Herring分组进行比较。
16个股骨评为Herring A或B级，3个股骨为Herring B - C级，12个股骨为Herring C级。与未受影响侧相比，患侧股骨骨骺（P < 0.001）和干骺端（P < 0.0001）的ADC均升高。股骨干骺端的ADC比值与Herring分类呈正相关：若高于1.63，则提示预后不良（Herring B - C或C级）（P = 0.0017，敏感性 = 89%，特异性 = 58%）。ADC测量的观察者间可靠性良好。1.63的阈值在凝固期即可确定。
扩散加权成像具有多种优势，包括无辐射、非侵入性。无需注射造影剂，且无需麻醉即可进行。ADC升高的原因尚不清楚。基本上，它反映了分子变化（真正的扩散），但也受血管供应（伪扩散）的影响。在Herring分类适用之前，ADC比值可为早期预后提供参考。
III级。前瞻性非对照研究。
