| 庄勋慧,冯卫华,徐文坚,曹会志.迭代重建技术在CT检查青年骶髂关节中的应用[J].中国医学影像技术,2012,28(4):796~799 |
| 迭代重建技术在CT检查青年骶髂关节中的应用 |
| Application of CT iterative reconstruction of sacroiliac joint in youth |
| 投稿时间：2011-09-12 修订日期：2011-11-19 |
| DOI： |
| 中文关键词: 统计迭代 体层摄影术,螺旋计算机 骶髂关节 噪声 图像质量 |
| 英文关键词:Iterative reconstruction Tomography, spiral computed Sacroiliac joint Noise Image quality |
| 基金项目: |
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| 摘要点击次数: 3052 |
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| 中文摘要: |
| 目的 探讨自适应统计迭代重建(ASIR)技术对青年患者骶髂关节CT图像噪声和质量的影响。方法 应用宝石能谱CT(Discovery CT 750HD)对30例青年患者行骶髂关节CT螺旋扫描。分别采用传统滤过反投影法(FBP组)和ASIR算法对原始投影数据进行重建,后者以10%为间隔在10%~100%间重建10组图像(ASIR组)。比较不同重建图像在同一层面的图像标准差(SD值)及平均CT值,并计算SNR和对比噪声比(CNR)。采用Likert 5分制评估图像质量,通过Kappa方法评价观察者间的一致性。对FBP图像和10组ASIR图像测量结果进行方差分析,对图像噪声和ASIR取值进行相关分析。结果 客观分析:①10%~100%ASIR图像的SD值小于FBP组(P<0.05),对应图像的SD值分别降低5.79%、11.44%、16.92%、21.78%、26.85%、32.12%、37.45%、40.32%、43.89%、47.27%;而图像CT值差异无统计学意义;②30%~100%ASIR各组图像SNR值高于FBP组(P均<0.05);③40%~100%ASIR各组图像CNR值高于FBP组(P均<0.05);④40%、50%、60%ASIR各组间SD值、SNR值及CNR值差异均无统计学意义(P>0.05);⑤图像噪声与ASIR百分比呈负相关(r=－0.613,P<0.05)。主观分析:①图像评定结果的观察者间一致性中等(Kappa=0.483);②30%~70%ASIR图像评分值高于FBP组(P<0.05),其中40%、50%、60%ASIR图像评分较高。结论 与FBP相比,ASIR技术可降低青年骶髂关节CT噪声,有效改善图像质量;ASIR取值为40%~60%时可获得最佳图像质量。 |
| 英文摘要: |
| Objective To investigate the impact of adaptive statistical iterative reconstruction (ASIR) technique on image quality and image noise of sacroiliac joint CT in youth. Methods Thirty patients underwent sacroiliac joint CT scan using Gemstone Spectral CT (Discovery CT 750HD). The raw data were reconstructed with filtered back projection (FBP) and ASIR (10%—100% ASIR, step 10%), respectively. The standard deviation (SD value) and average CT value were measured on the same level of different reconstructed images, then the SNR and contrast to noise ratio (CNR) were calculated. Image quality was evaluated using a 5-point scale. Kappa method was used to evaluate the consistency between the assessment results of two observers. The results of FBP and ASIR were analyzed by variance analysis, and correlation analysis was made between image noise and ASIR. Results Objective analysis: ①SD values on 10%—100% ASIR images were smaller than on FBP images (P<0.05) without difference of CT value. In comparison with FBP, SD values reduced by 5.79%, 11.44%, 16.92%, 21.78%, 26.85%, 32.12%, 37.45%, 40.32%, 43.89%, 47.27% on ASIR images, respectively. ②SNR values on 30%—100% ASIR images were larger than those on FBP images (all P<0.05). ③CNR values on 40%—100% ASIR images were larger than those on FBP images (all P<0.05). ④There was no significant difference among 40%, 50%, 60% ASIR in SD values, SNR nor CNR (P>0.05). ⑤Negative correlation was found between image noise and ASIR percentage (r=－0.613, P<0.05). Subjective analysis: ①The assessment scores between two observers obtained medium consistency in subjective image evaluation (Kappa=0.483). ②There were significant differences in assessment scores between 30%—70%ASIR and FBP, while 40%—60% ASIR images had higher scores. Conclusion Compared with FBP,ASIR technique can result in noise reduction and image quality improvement of sacroiliac joint CT in youth. Reconstruction using 40%—60% ASIR values can significantly improve image quality. |
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