借助CT三维重建测量值开展茎突数字断层融合检查体位的优化设计及评估

Design and evaluation of the optimized styloid digital tomosynthesis examination posture by three-dimensional CT reconstruction measurements

目的:以头颈部仿真体模为实验对象,借助CT三维重建测量值开展茎突数字断层融合(DTS)检查体位的优化设计研究及评估工作。方法:使用128层螺旋CT对头颈体模行螺旋扫描,借助CT后处理工作站测出茎突的前倾角、内倾角和长度,进而设计出DTS茎突正、侧位检查的优化体位,对同一体模行DTS茎突传统正、侧位和优化正、侧位扫描,在DTS后处理工作站上分别重建各体位的左右两侧茎突并测出其长度,以CT测得值作为参考值,对比分析DTS不同检查体位和重建方式下茎突长度测量值的准确情况。结果:CT三维重建技术测得茎突前倾角和内倾角分别为左侧21°和24°,右侧22°和28°;茎突长度为左侧21.0 mm,右侧21.4 mm。DTS茎突优化正、侧位重建图像中,正位和近侧位茎突长度测量值近乎一致(左侧21.5 mm,右侧22.1 mm),与参考值的偏差均在1 mm以内,偏差度小于5%,符合临床需求,且比传统体位测得值(传统正位左侧19.0 mm,右侧19.3 mm;传统侧位近侧左侧19.2 mm,右侧22.6 mm;远侧左侧18.5 mm,右侧18.0 mm)更为准确,而优化侧位的远侧茎突长度测量值的偏差值(左侧8.8 mm,右侧4.4 mm)和偏差度(左侧41.9%,右侧20.6%)均较大,不符合临床要求。结论:借助CT三维重建测量值设计的茎突DTS检查的优化体位具有极佳的应用价值,明确DTS检查中茎突长度的测量应在优化后的正位和近侧位图像上进行,远侧位图像不可用于茎突长度的测量。

Objective Taking the head and neck anthropomorphic phantom as the experimental object to design and evaluate the styloid digital tomosynthesis(DTS)examination posture optimized by three-dimensional CT reconstruction measurements.Methods A128-layer spiral CT was used to scan the head and neck anthropomorphic phantom.The anterior oblique angle,internal oblique angle and length of the styloid process were measured by CT post-processing station,thereby determining the optimized anteroposterior and lateral postures for the DTS examination of the styloid process.The traditional and optimized anteroposterior and lateral scans for the DTS examination of the styloid process were performed on the same anthropomorphic phantom,and the left and right lengths of the styloid process in different postures were measured after the styloid process was reconstructed on DTS post-processing station.The CT measurements were taken as the reference values to compare and analyze the accuracy of the length measurement of the styloid process under different DTS examination postures and reconstruction methods.Results The anterior oblique angle and internal oblique angle of the styloid process measured by three-dimensional CT reconstruction technology were 21°and 24°at the left side,22°and 28°at the right side,and the left and right lengths of the styloid process were 21.0 mm and 21.4 mm.In the optimized anteroposterior and proximal lateral reconstruction images obtained in the DTS examination of the styloid process,the left and right lengths of the styloid process were nearly equal(21.5 mm vs 22.1 mm),and their deviations from the reference value were less than 1 mm and the deviation degrees were less than 5%,which met the clinical requirements.The measurements were more accurate than the data acquired in the traditional postures which had 19.0 mm(left)and 19.3 mm(right)in the traditional anteroposterior reconstruction images,19.2 mm(left)and 22.6 mm(right)in the traditional proximal lateral reconstruction images,and 18.5 mm(left)and 18 mm(right)in the traditional distal lateral reconstruction images.However,the deviation value(8.8 mm at the left side and 4.4 mm at the right side)and deviation degree(41.9%and 20.6%at the two sides)of the measurements of the distal styloid process lengths in optimized lateral posture were much larger,which did not meet the clinical requirements.Conclusion The optimized styloid DTS examination postures designed by three-dimensional CT reconstruction measurements have high application value.The measurement of styloid length in DTS examination should be carried out on the optimized anteroposterior and proximal lateral images,and the distal lateral images can not be used in the measurement of styloid length.