Objective To investigate the value of the adaptive statistical iterative reconstruction (ASIR) algorithm for reducing the radiation dose and optimizing the image quality in the low-dose spectral CT scanning in GSl (Gemstone spectral imaging) of the liver.Methods A total of 60 patients who underwent hepatic spectral CT scanning in GSI were enrolled in this study.The patients were randomly divided into two groups according to priority with 30 cases per group.Low-dose spectral CT scanning was used for group A, and images were reconstructed by ASIR 0 and 50％ , marked as A1 and A2.Group B was scanned with conventional dose of spectral CT, and images were reconstructed by Filtered back projection (FBP).Effective doses (E) for each group were calculated.Image quality was assessed by two radiologists, and the radiation doses were compared between groups A and B.Results All image quality of each group were good enough for clinical diagnosis.E for group A and B were (3.2 ±0.2) and (5.8 ± 0.2) mSv, respectively.There was statistical difference with image noise between group A and B(Z =-6.784,P ＜ 0.05).The image noise, SNR and CNR had statistical differences between group A and B (F =24.013, 15.646, 8.285, P ＜0.05).Compared with group A1, the image noise was lower, and the SNR and CNR were higher in groups A2 and B(P ＜ 0.05).There were no statistical differences of image noise, SNR and CNR between groups A2 and B (P ＞ 0.05).There were no statistical differences of the image quality score between groups A1, A2 and B (F =102.38,105.768, P ＜ 0.05).Conclusions ASIR combined with low-dose spectral CT scanning was helpful to reduce radiation dose and could obtain better image quality in hepatic CT examination.

ObjectiveUltra performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry（UPLC-Q-Exactive Orbitrap MS） was used to analyze the differences in chemical components between raw products and wine-processed products of Polygonatum cyrtonema rhizome. MethodUPLC-Q-Exactive Orbitrap MS was used to analyze the chemical compositions of P. cyrtonema rhizome before and after processing， and the effective response ions were extracted after raw data processing， and the differential compounds before and after processing were screened combined with multivariate statistical analysis and according to the conditions of variable importance in the projection（VIP） value>1， P<0.05， fold change（FC）>2 or FC<0.5， based on the retention time， quasi-molecular ions， fragment ions and other information， the components were identified in combination with the control products and the literature， and the significant difference compounds were identified by clustering thermal analysis and relative quantitative analyzed， in order to clarify the change rule of the main components in P. cyrtonema rhizome before and after processing. ResultA total of 72 differential constituents between raw products and wine-processed products were identified， including 15 alkaloids， 12 organic acids， 12 amino acids， 6 flavonoids， 4 saccharides and 23 others. There were a total of 18 significantly different components， among which 13 compounds， including L-malic acid， lactic acid and 9，12，13-trihydroxy-10-octadecenoic acid， showed an increasing trend in content after wine processing， 5 compounds such as trans-3-indoleacrylic acid， L-arginine， D-tryptophan， showed a decreasing trend after processing. ConclusionThe chemical components of P. cyrtonema rhizome are significantly different before and after processing， mainly organic acids， saccharides， amino acids， flavonoids and alkaloids， which can lay the foundation for the in-depth study of the processing mechanism of Polygonati Rhizoma.