Department of Medical Techniques, Shaanxi University of Chinese medicine, Xianyang, China.
Department of Radiology, Affiliated Hospital of Shaanxi University of Chinese medicine, Xianyang, China.
Br J Radiol. 2019 Jan;92(1093):20180137. doi: 10.1259/bjr.20180137. Epub 2018 Sep 21.
To evaluate the ability of a model-based iterative reconstruction (MBIR) for improving image quality in upper abdominal CT with quarter of the normal dose, in comparison with adaptive statistical iterative reconstruction (ASiR) at normal dose.
40 upper abdominal patients were randomly divided into two groups: normal-dose group ( = 20) with tube current modulation for noise index (NI) of 10 HU and 40% ASiR reconstruction; low-dose group ( = 20) with NI = 20 HU in the delay phase and MBIR and 40%ASiR. Images in the delay phase were compared. The CT values and standard deviation (SD) values of the liver, spleen, pancreas, kidney, erector spine and fat were measured. Contrast-noise-ratio (CNR = (CT-CT )/SD) of each measured organ were calculated and compared with one-way ANOVA among the three reconstruction groups. The subjective image scores of the three groups were assessed blindly by two experienced physicians using a 5-point system and the score consistency was compared by the κ test.
Dose reduction of 75 % was achieved for the low-dose scan. The subjective scores (95 % confidence intervals) of the three groups (NI 10-40 % ASiR, NI 20-40% ASiR and NI 20-MBIR) were 4.00 ± 0.79 (3.62-4.37), 3.35 ± 0.58 (3.07-3.62) and 3.90 ± 0.64 (3.60-4.19), respectively with no difference between the NI 10-40% ASiR and NI20-MBIR groups and good consistency between reviewers (κ = 0.726). MBIR had statistically lower SD values and higher contrast-to-noise ratio values in the liver, spleen, pancreas, kidney and erector spine than NI 10-40% ASiR and NI 20-40% ASiR (all < 0.05).
At 75 % dose reduction, MBIR provides similar image quality compared to 40% ASiR at normal-dose.
MBIR provides good image quality at 25 % of the normal dose.
与常规剂量下的自适应统计迭代重建（ASiR）相比，评估基于模型的迭代重建（MBIR）在四分之一常规剂量下提高上腹部 CT 图像质量的能力。
将 40 例上腹部患者随机分为两组：常规剂量组（n=20），管电流调制噪声指数（NI）为 10HU，采用 40%ASiR 重建；低剂量组（n=20），在延迟期采用 NI=20HU、MBIR 和 40%ASiR。比较延迟期图像。测量肝脏、脾脏、胰腺、肾脏、竖脊肌和脂肪的 CT 值和标准差（SD）值。计算每个测量器官的对比噪声比（CNR=（CT-CT）/SD），并采用单因素方差分析比较三组重建方法之间的差异。由两位经验丰富的医生对三组的主观图像评分进行盲法评估，采用 5 分制，并采用κ检验比较评分一致性。
低剂量扫描的剂量减少了 75%。三组的主观评分（95%置信区间）分别为：NI 10-40%ASiR、NI 20-40%ASiR 和 NI 20-MBIR 组为 4.00±0.79（3.62-4.37）、3.35±0.58（3.07-3.62）和 3.90±0.64（3.60-4.19），NI 10-40%ASiR 组与 NI20-MBIR 组之间无差异，两位审阅者的一致性较好（κ=0.726）。MBIR 组在肝脏、脾脏、胰腺、肾脏和竖脊肌的 SD 值低于 NI 10-40%ASiR 组和 NI 20-40%ASiR 组，而 CNR 值高于后两者（均 P<0.05）。
在 75%的剂量减少下，MBIR 提供与常规剂量下 40%ASiR 相似的图像质量。
MBIR 在常规剂量的 25%下提供良好的图像质量。
