Department of Radiology, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan.
Department of Radiology Services, Gifu University Hospital, 1-1 Yanagido, Gifu, 501-1194, Japan.
Abdom Radiol (NY). 2021 Sep;46(9):4238-4244. doi: 10.1007/s00261-021-03111-x. Epub 2021 May 11.
To evaluate image quality, image noise, and conspicuity of pancreatic ductal adenocarcinoma (PDAC) in pancreatic low-dose computed tomography (LDCT) reconstructed using deep learning image reconstruction (DLIR) and compare with those of images reconstructed using hybrid iterative reconstruction (IR).
Our institutional review board approved this prospective study. Written informed consent was obtained from all patients. Twenty-eight consecutive patients with PDAC undergoing chemotherapy (14 men and 14 women; mean age, 68.4 years) underwent pancreatic LDCT for therapy evaluation. The LDCT images were reconstructed using 40% adaptive statistical iterative reconstruction-Veo (hybrid-IR) and DLIR at medium and high levels (DLIR-M and DLIR-H). The image noise, diagnostic acceptability, and conspicuity of PDAC were qualitatively assessed using a 5-point scale. CT numbers of the abdominal aorta, portal vein, pancreas, PDAC, background noise, signal-to-noise ratio (SNR) of the anatomical structures, and tumor-to-pancreas contrast-to-noise ratio (CNR) were calculated. Qualitative and quantitative parameters were compared between the hybrid-IR, DLIR-M, and DLIR-H images.
CT dose-index volumes and dose-length product in pancreatic LDCT were 2.3 ± 1.0 mGy and 74.9 ± 37.0 mGy•cm, respectively. The image noise, diagnostic acceptability, and conspicuity of PDAC were significantly better in DLIR-H than those in hybrid-IR and DLIR-M (all P < 0.001). The background noise was significantly lower in the DLIR-H images (P < 0.001) and resulted in improved SNRs (P < 0.001) and CNR (P < 0.001) compared with those in the hybrid-IR and DLIR-M images.
DLIR significantly reduced image noise and improved image quality in pancreatic LDCT images compared with hybrid-IR.
评估深度学习图像重建（DLIR）在胰腺低剂量 CT（LDCT）重建中对胰腺导管腺癌（PDAC）的图像质量、图像噪声和显影效果，并与混合迭代重建（IR）的图像进行比较。
本研究经机构审查委员会批准，所有患者均签署了书面知情同意书。连续 28 例接受化疗的 PDAC 患者（14 名男性，14 名女性；平均年龄，68.4 岁）接受了胰腺 LDCT 进行治疗评估。LDCT 图像分别采用 40%自适应统计迭代重建-Veo（混合-IR）和中、高（DLIR-M 和 DLIR-H）水平的 DLIR 进行重建。采用 5 分制对 PDAC 的图像噪声、诊断可接受性和显影效果进行定性评估。计算腹主动脉、门静脉、胰腺、PDAC、背景噪声、解剖结构的信噪比（SNR）和肿瘤-胰腺对比噪声比（CNR）的 CT 值。比较混合-IR、DLIR-M 和 DLIR-H 图像之间的定性和定量参数。
胰腺 LDCT 的 CT 剂量指数体积和剂量长度乘积分别为 2.3 ± 1.0 mGy 和 74.9 ± 37.0 mGy·cm。DLIR-H 组的图像噪声、诊断可接受性和 PDAC 显影效果均显著优于混合-IR 和 DLIR-M 组（均 P < 0.001）。DLIR-H 组的背景噪声显著降低（P < 0.001），与混合-IR 和 DLIR-M 组相比，SNR（P < 0.001）和 CNR（P < 0.001）均显著提高。
与混合-IR 相比，DLIR 可显著降低胰腺 LDCT 图像的噪声，提高图像质量。
