Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Eberhard Karls University Tübingen, Hoppe-Seyler-Str, Tübingen, Germany.
Department of Traumatology and Reconstructive Surgery, BG Trauma Center Tübingen, Eberhard Karls University of Tübingen, Schnarrenberg-Str, Tübingen, Germany.
Br J Radiol. 2023 Mar 1;96(1144):20220495. doi: 10.1259/bjr.20220495. Epub 2023 Feb 14.
Patients who need torsion measurement of the lower limb often have metal implants hindering . MRI. A new ultra-low-dose (ULD-)CT protocol might be feasible for torsion measurement at cost of relatively low radiation exposure.
We retrospectively included all patients with clinically indicated torsion measurement in the period July 2019 to June 2021 and metal implants in the scanning field. The ULD-CT protocol comprised automated tube current time product and automated tube voltage with reference settings of 100kV/20mAs (hip), 80kV/20mAs (knee) and 80kV/10mAs (ankle). Femoral neck anteversion, tibial, intra-articular knee and overall leg torsion measurements were performed by two radiologists independently. Diagnostic confidence regarding the delineation of the relevant cortical bone was rated on a 5-point Likert scale (1 = non-diagnostic, 5 = excellent).
102 consecutive patients could be included (BMI 27.38 ± 5.85) with 154 metal implants. Median total dose length product of the ULD-CT-torsion measurement was 16.5mGycm [11-39]. Both readers showed high agreement with a maximum torsional difference of 4.1°. Diagnostic confidence was rated best (5/5) in 92.2% (reader 1) and 93.1% (reader 2) with a worst rating of 3/5.
The new ULD-CT protocol is feasible for torsion measurement of the lower limb - even in patients with metal implants.
Metal implants are not an obstacle for ULD-CT torsion measurements of the lower limb.
需要下肢扭转测量的患者常因金属植入物而妨碍 MRI 检查。一种新的超低剂量（ULD-）CT 方案可能可以用于测量扭转，其辐射暴露相对较低。
我们回顾性纳入了 2019 年 7 月至 2021 年 6 月期间因临床指征需要进行扭转测量且扫描野有金属植入物的所有患者。ULD-CT 方案包括自动管电流时间乘积和自动管电压，参考设置为 100kV/20mAs（髋部）、80kV/20mAs（膝部）和 80kV/10mAs（踝部）。两位放射科医生独立进行股骨颈前倾角、胫骨、关节内膝关节和整个腿部扭转测量。使用 5 分李克特量表（1=无法诊断，5=优秀）对相关皮质骨的描绘诊断信心进行评分。
共纳入 102 例连续患者（BMI 27.38±5.85），有 154 个金属植入物。ULD-CT 扭转测量的总剂量长度乘积中位数为 16.5mGycm[11-39]。两位读者的最大扭转差异为 4.1°，具有很高的一致性。92.2%（读者 1）和 93.1%（读者 2）的诊断信心评分最佳（5/5），最差评分为 3/5。
新的 ULD-CT 方案可行用于下肢扭转测量，即使在有金属植入物的患者中也是如此。
金属植入物不是下肢 ULD-CT 扭转测量的障碍。
