CAJ | 학술논문

目的：探讨自适应统计迭代重建（ASIR）技术对泌尿系统结石CT图像噪声和质量的影响。方法应用宝石能谱CT （Discovery CT 750 HD）对20例尿路结石患者进行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20％为间隔在20％～100％间重建5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，并计算信噪比和对比噪声比（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5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：①20％～100％ASIR图像的SD值小于FBP组（P＜0.05），而图像CT值差异无统计学意义；②40％～100％ASIR各组图像SNR、CNR值高于FBP组（P均＜0.05）；③图像噪声与ASIR百分比呈负相关（r=-0.529）。主观分析：①图像评定结果的观察者间一致性中等（Kappa=0.412）；②40％～100％ASIR图像评分值高于FBP组（P＜0.05）。其中60％～100％ASIR图像评分较高。结论与FBP相比，ASIR技术可降低肾结石CT噪声，有效改善图像质量；ASIR取值为60％～100％时可获得最佳图像质量。
목적：탐토자괄응통계질대중건（ASIR）기술대비뇨계통결석CT도상조성화질량적영향。방법응용보석능보CT （Discovery CT 750 HD）대20례뇨로결석환자진행CT라선소묘。분별채용전통려과반투영법（FBP조）화ASIR산법대원시투영수거진행중건，후자이20％위간격재20％～100％간중건5조도상（ASIR조）。비교불동중건도상재동일층면적도상표준차（SD치）급평균CT치，병계산신조비화대비조성비（CNR），채용Likert 5분제평고도상질량，통과Kappa방법평개관찰자간적일치성。대FBP도상화5조ASIR도상측량결과진행방차분석，대도상조성화ASIR취치진행상관분석。결과객관분석：①20％～100％ASIR도상적SD치소우FBP조（P＜0.05），이도상CT치차이무통계학의의；②40％～100％ASIR각조도상SNR、CNR치고우FBP조（P균＜0.05）；③도상조성여ASIR백분비정부상관（r=-0.529）。주관분석：①도상평정결과적관찰자간일치성중등（Kappa=0.412）；②40％～100％ASIR도상평분치고우FBP조（P＜0.05）。기중60％～100％ASIR도상평분교고。결론여FBP상비，ASIR기술가강저신결석CT조성，유효개선도상질량；ASIR취치위60％～100％시가획득최가도상질량。
Objective To investigate the impact of adaptive statistical iterative reconstruction(ASIR) technique on image quality and image noise of urinary calculi. Methods Twenty patients with urinary calculi underwent CT scan using Gemstone spectral CT (Discovery CT 750 HD). The raw data were reconstructed with filtered back projection (FBP) and ASIR (20%-100% ASIR, step 20%), 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: ① SD values on 20%-100% ASIR images were smaller than on FBP images (P<0.05) without difference of CT value. In comparison with FBP, SD values reduced ASIR images,respectively. ② SNR and CNR values on 40%-100%ASIR images were larger than those on FBP images(all P<0.05). ③ Negative correlation was found between image noise and ASIR percentage (r=-0.529).Subjective analysis: ① The assessment scores between two observers obtained medium consistency in subjective image evaluation (Kappa=0.412).②There were significant differences in assessment scores between 40%-100%ASIR and FBP, while 60%-100% ASIR images had higher scores. Conclusion Compared with FBP, ASIR technique can result in noise reduction and image quality improvement of urinary calculi. Reconstruction using 60%-100% ASIR values can significantly improve image quality.