能谱CT单能量成像联合迭代重组技术优化卵巢动脉显示的临床价值

Clinical value of ovarian artery image quality with spectral CT monochromatic imaging and adaptive statistical iterative reconstruction technique

目的探讨能谱CT单能量成像联合自适应统计迭代重组(ASIR)技术在优化卵巢动脉图像质量中的临床价值。方法前瞻性收集因盆腔占位行全腹部增强扫描的女性患者,64例(对照组和试验组各32例)纳入本研究。对照组采用120 k Vp管电压常规扫描,联合40%ASIR重建图像;试验组采用能谱(GSI)扫描,选取40~70 ke V,以5 ke V为间隔,共7个水平单能量图像分别联合30%~60%ASIR重建。测量所有图像动脉期卵巢动脉的对比噪声比(CNR)和信噪比(SNR),采用单因素方差分析及独立样本t检验比较。由两名放射科医师采用5分评分制法对两组图像动脉期图像质量进行主观评价,采用Mann-Whitney U检验比较,一致性采用Kappa检验。结果随着单能量水平的升高,卵巢动脉的CT值逐渐降低;卵巢动脉CNR及SNR在40 ke V联合60%ASIR(26.12±7.92、30.45±8.13)时均最高,与对照组(13.29±5.44、18.67±5.61)比较差异均有统计学意义(P<0.05);试验组主观评分在40 ke V联合50%ASIR时最高(4.18±0.63),与40 ke V联合60%ASIR(4.12±0.64)比较差异无统计学意义(P>0.05),明显高于对照组(P<0.05)。结论能谱CT单能量成像联合迭代重组技术既不增加辐射剂量,且在40 ke V单能量水平联合60%ASIR可明显提高卵巢动脉的图像质量,对临床诊断和治疗提供帮助。

Objective To investigate the clinical value of spectral CT monochromatic imaging and adaptive statistical iterative reconstruction technique on the image quality of ovarian artery. Methods 64 patients who had pelvic occupied lesion underwent abdominal contrast enhanced CT were randomly assigned into the control group(n=32) and study group(n=32). The control group scanned with 120 k Vp tube voltage and the images reconstructed with 40% ASIR. The study group scanned with gemstone spectral imaging(GSI)(GE Discovery CT), and the spectral monochromatic images 40-70 ke V(intervals of 5 ke V, 7 levels) were reconstructed with 30%-60% ASIR(5 levels) respectively. The contrast-to-noise ratios(CNR) and signal-to-noise ratios(SNR) were measured. Two radiologists independently and blindly assessed the subjective image quality. The results were analyzed with one-way analysis of variance, independent sample t-test and Mann-Whitney U test. Results CT values of ovarian artery decreased with the monochromatic imaging. Ovarian artery CNR and SNR at 40 ke V reconstructed with 60% ASIR(26.12± 7.92, 30.45± 8.13) reached the maximal, and higher than that at 120 k Vp reconstructed with 40% ASIR(13.29± 5.44, 18.67± 5.61)(all P<0.05). At 40 ke V reconstructed with 50% ASIR(4.18± 0.63) yielded a maximal subjective image quality score, similar scores to that at 40 ke V reconstructed with 60% ASIR(4.12±0.64), and higher than that at 120 k Vp reconstructed with 40% ASIR(P<0.05). Conclusions Spectral CT monochromatic imaging and adaptive statistical iterative reconstruction technique can optimize the image quality of ovarian artery at 40 ke V reconstructed with 60% ASIR, without radiation dose increasing, which is of great benefit to the clinical diagnosis and treatment.