Geijer Mats, Rundgren Gustav, Weber Lars, Flivik Gunnar
1 Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
2 Department of Clinical Sciences, Lund University, Lund, Sweden.
Acta Radiol. 2017 Oct;58(10):1276-1282. doi: 10.1177/0284185117693462. Epub 2017 Mar 27.
Background Recently, total hip arthroplasty (THA) has come to focus on restoration of individual anatomy including femoral neck anteversion and global offset (femoral and acetabular offset). Three-dimensional (3D) computed tomography (CT) data could provide a better basis for preoperative templating. The use of CT has been hampered by high radiation dose. Purpose To evaluate the effective dose used in pelvis and hip CT for THA templating. Material and Methods CT data from two clinical trials of THA were evaluated for CT scan length and volume CT dose index (CTDI). The effective doses from hip-knee-ankle CT and pelvis and hip radiography were compared. Conversion factors for effective dose for radiography were calculated using the PCXMC software. Results A reduced dose CT protocol for pelvis imaging gave a substantial dose reduction compared with standard CT, while maintaining sufficient image quality. Between the two clinical trials there was a significant reduction in effective CT dose corresponding to changes in the CT protocol ( P < 0.01). The CT dose for the latter group was similar to, but nevertheless significantly higher than for, radiography ( P < 0.01). However, in the latter group the theoretical minimum dose for CT, using the minimum scan length required by the templating software, was equal to the dose from radiography. Conclusion Although the CT dose remained higher than for radiography, potential reductions in scan length could reduce the dose further so that CT would have a comparable level of risk to radiography with the added benefit of 3D templating.
背景 最近，全髋关节置换术（THA）已开始关注个体解剖结构的恢复，包括股骨颈前倾角和整体偏移（股骨和髋臼偏移）。三维（3D）计算机断层扫描（CT）数据可为术前模板制作提供更好的基础。然而，CT的使用因高辐射剂量而受到限制。目的 评估用于THA模板制作的骨盆和髋关节CT的有效剂量。材料与方法 对两项THA临床试验的CT数据进行评估，以确定CT扫描长度和容积CT剂量指数（CTDI）。比较了髋-膝-踝CT与骨盆及髋关节X线摄影的有效剂量。使用PCXMC软件计算X线摄影有效剂量的转换因子。结果 与标准CT相比，用于骨盆成像的低剂量CT方案在保持足够图像质量的同时，显著降低了剂量。在两项临床试验之间，随着CT方案的改变，有效CT剂量显著降低（P < 0.01）。后一组的CT剂量与X线摄影相似，但仍显著高于X线摄影（P < 0.01）。然而，在后一组中，使用模板制作软件所需的最小扫描长度时，CT的理论最小剂量与X线摄影的剂量相等。结论 尽管CT剂量仍高于X线摄影，但扫描长度的潜在减少可能会进一步降低剂量，从而使CT与X线摄影具有相当的风险水平，同时还具有3D模板制作的额外优势。
