Meyrignac Olivier, Moreno Ramiro, Baunin Christiane, Vial Julie, Accadbled Franck, Sommet Agnes, de Gauzy Jérome Sales, Sans Nicolas
Department of Radiology, CHU Toulouse Purpan, Place du Docteur Baylac, TSA 40031, 31059, Toulouse Cedex 9, France,
Eur Radiol. 2015 Jun;25(6):1752-60. doi: 10.1007/s00330-014-3560-8. Epub 2014 Dec 23.
To evaluate in children the agreement between femoral and tibial torsion measurements obtained with low-dose biplanar radiography (LDBR) and CT, and to study dose reduction ratio between these two techniques both in vitro and in vivo.
Thirty children with lower limb torsion abnormalities were included in a prospective study. Biplanar radiographs and CTs were performed for measurements of lower limb torsion on each patient. Values were compared using Bland-Altman plots. Interreader and intrareader agreements were evaluated by intraclass correlation coefficients. Comparative dosimetric study was performed using an ionization chamber in a tissue-equivalent phantom, and with thermoluminescent dosimeters in 5 patients.
Average differences between CT and LDBR measurements were -0.1° ±1.1 for femoral torsion and -0.7° ±1.4 for tibial torsion. Interreader agreement for LDBR measurements was very good for both femoral torsion (FT) (0.81) and tibial torsion (TT) (0.87). Intrareader agreement was excellent for FT (0.97) and TT (0.89). The ratio between CT scan dose and LDBR dose was 22 in vitro (absorbed dose) and 32 in vivo (skin dose).
Lower limb torsion measurements obtained with LDBR are comparable to CT measurements in children and adolescents, with a considerably reduced radiation dose.
• LDBR and CT lower-limb torsion measurements are comparable in children and adolescents. • LDBR considerably reduced radiation dose necessary for lower-limb torsion measurements. • LDBR can be used for evaluation of lower limb-torsion in orthopaediatric patients.
评估儿童中使用低剂量双平面X线摄影（LDBR）和CT获得的股骨和胫骨扭转测量值之间的一致性，并研究这两种技术在体外和体内的剂量降低率。
30例下肢扭转异常的儿童纳入一项前瞻性研究。对每位患者进行双平面X线摄影和CT检查以测量下肢扭转。使用Bland-Altman图比较测量值。通过组内相关系数评估不同阅片者之间以及同一阅片者内部的一致性。在组织等效体模中使用电离室，并在5例患者中使用热释光剂量计进行比较剂量学研究。
CT和LDBR测量的平均差异为：股骨扭转-0.1°±1.1，胫骨扭转-0.7°±1.4。LDBR测量的不同阅片者之间的一致性对于股骨扭转（FT）（0.81）和胫骨扭转（TT）（0.87）都非常好。同一阅片者内部的一致性对于FT（0.97）和TT（0.89）都非常好。CT扫描剂量与LDBR剂量之比在体外（吸收剂量）为22，在体内（皮肤剂量）为32。
LDBR获得的儿童和青少年下肢扭转测量值与CT测量值相当，且辐射剂量显著降低。
• LDBR和CT对儿童和青少年下肢扭转的测量结果相当。• LDBR显著降低了下肢扭转测量所需的辐射剂量。• LDBR可用于评估小儿骨科患者的下肢扭转情况。
