Ruff Andrew, Li Xiaochun, Goldberg Judith D, Ehrhart Mark, Ginocchio Luke, Smereka Paul, O'Donnell Thomas, Dane Bari
New York University, New York, USA.
University of New Mexico, Albuquerque, USA.
Abdom Radiol (NY). 2025 Jan 7. doi: 10.1007/s00261-024-04696-9.
As the pancreas is a low contrast visibility organ, pancreatic ductal adenocarcinoma detection is challenging due to subtle attenuation differences between tumor and pancreatic parenchyma. Photon counting CT (PCCT) has superior iodine contrast-to-noise ratio than conventional CT and also affords the creation of low keV virtual monoenergetic images, both of which increase adenocarcinoma conspicuity. The purpose therefore was to identify the optimal virtual monoenergy for visualizing PDAC during the pancreatic parenchymal phase of enhancement at PCCT using both quantitative and qualitative analyses.
Consecutive patients with pancreatic parenchymal phase PCCT source data were retrospectively identified by PACS search. For the quantitative analysis, region of interest (ROI) measurements were drawn in the pancreatic head, body, tail, pancreatic adenocarcinoma (if present), and psoas muscles on 40-120 keV virtual monoenergetic images in 10 keV increments. Based on the quantitative analysis results and vendor recommendations, four virtual monoenergies(40 keV, 55 keV, 70 keV, and 85 keV) were selected for additional qualitative analysis. Three radiologists blinded to four virtual monoenergies assessed overall image quality, image noise, pancreatic enhancement, and pancreatic mass conspicuity on 5-point Likert scales.
54 patients (28/54 male, mean[SD] age: 62 [13] years) were included. Quantitatively, 40 keV had the highest pancreatic parenchymal CNR and attenuation difference between the adenocarcinoma and parenchyma, but also the highest noise (HUsd). Qualitatively, 70 keV had the best overall image quality (Mean [SE]: 3.7[0.1]) and lower noise than 40 and 55 keV (3.6[0.08] vs. 1.8[0.07] and 2.7[0.05], respectively, p < .001). 40 keV had the greatest pancreatic enhancement (mean[SE] 4.6[0.11]). Adenocarcinoma conspicuity ratings were greatest at 40 keV and 55 keV, and not significantly different from each other (mean[SE] 4.4[0.13] and 4.3[0.14], respectively, Tukey adj-p =.20). 55 keV had greater overall image quality and lower noise than 40 keV (mean[SE] 3.4[0.08] vs. 2.5[0.08], Tukey adj-p < .001 and 2.7[0.05] vs. 1.8[0.07], Tukey adj-p < .001 respectively).
55 keV pancreatic parenchymal phase virtual monoenergetic images afford optimal pancreatic assessment at PCCT for the visualization of pancreatic adenocarcinoma. Routinely viewing 55 keV virtual monoenergetic images at PCCT may improve PDAC detection.
由于胰腺是一个对比度较低的可视器官，肿瘤与胰腺实质之间细微的衰减差异使得胰腺导管腺癌的检测具有挑战性。光子计数CT（PCCT）的碘对比噪声比优于传统CT，并且还能生成低keV虚拟单能量图像，这两者都能提高腺癌的可视性。因此，本研究的目的是通过定量和定性分析，确定在PCCT胰腺实质强化期可视化胰腺导管腺癌（PDAC）的最佳虚拟单能量。
通过PACS搜索回顾性确定有胰腺实质期PCCT源数据的连续患者。对于定量分析，在40-120 keV的虚拟单能量图像上，以10 keV的增量在胰头、胰体、胰尾、胰腺腺癌（如果存在）和腰大肌中绘制感兴趣区域（ROI）进行测量。根据定量分析结果和供应商建议，选择四个虚拟单能量（40 keV、55 keV、70 keV和85 keV）进行额外的定性分析。三位对四个虚拟单能量不知情的放射科医生在5分李克特量表上评估整体图像质量、图像噪声、胰腺强化和胰腺肿块可视性。
纳入54例患者（28/54为男性，平均[标准差]年龄：62 [13]岁）。在定量方面，40 keV的胰腺实质对比噪声比最高，腺癌与实质之间的衰减差异最大，但噪声（HUsd）也最高。在定性方面，70 keV的整体图像质量最佳（平均[标准误]：3.7[0.1]），且噪声低于40 keV和55 keV（分别为3.6[0.08]与1.8[0.07]和2.7[0.05]，p <.001）。40 keV的胰腺强化最大（平均[标准误] 4.6[0.11]）。腺癌可视性评分在40 keV和55 keV时最高，且彼此之间无显著差异（平均[标准误]分别为4.4[0.13]和4.3[0.14]，Tukey校正p =.20）。55 keV的整体图像质量高于40 keV，噪声低于40 keV（平均[标准误] 3.4[0.08]与2.5[0.08]，Tukey校正p <.001；2.7[0.05]与1.8[0.07]，Tukey校正p <.001）。
55 keV胰腺实质期虚拟单能量图像在PCCT上能为胰腺腺癌的可视化提供最佳的胰腺评估。在PCCT上常规查看55 keV虚拟单能量图像可能会改善PDAC的检测。
