Objective To explore the value of deep learning image reconstruction(DLIR)algorithm to improve the quality of low keV monochromatic portal vein images of energy spectrum CT.Methods Fifty patients who underwent enhanced upper abdominal energy spectrum CT scan were selected.Mixed-model adaptive statistical iterative reconstruction-Veo(50%ASIR-V)algorithm and high-deep learning image reconstruction(DLIR-H)algorithm were used to obtain monochromatic images at 40-70 keV(with intervals of 10 keV).The CT and standard deviation(SD)values of the portal vein trunk,left and right branches,and erector spinae muscle were measured in the transverse position,and the signal-to-noise ratio(SNR)and portal vein contrast-to-noise ratio(CNR)were calculated for objective evaluation.The portal vein image quality between the two algorithms and different energy was subjectively scored by two physicians.Results In terms of objective evaluation:compared with 50%ASIR-V,the CNR and SNR of portal vein in monochromatic DLIR-H images at the same keV between 40-70 keV energy levels were increased while the SD value was decreased(P＜0.05),and the CT value was unchanged;there was no statistical difference in the magnitude of change in CNR between the two algorithms at different energy levels(P＞0.05);there was a statistically significant difference in the magnitude of change in SNR and SD value(P＜0.05)and the magnitude of change was the largest at 40 keV;comparison between different energy levels of DLIR-H,the CNR and SD value of 40 keV DLIR-H were the highest(P＜0.05),and there was no significant difference in the SNR(P＞0.05).In terms of subjective evaluation:there was no significant difference between the subjective scores of the two algorithms at the same keV from 40-70 keV(P＞0.05),and the two reconstruction algorithms at 40 keV and 50 keV had the highest subjective scores between different keV.Conclusion The DLIR algorithm can reduce the noise of low keV monochromatic images,improve the image quality of portal vein.

Objective To investigate the utility of dual-energy computed tomography(DECT)virtual non-contrast(VNC)images instead of true non-contrast(TNC)images in the quantitative analysis of emphysema.Methods A retrospective selection was con-ducted on 59 patients who underwent chest CT plain scan plus dual-phase enhanced scan on APEX-CT.VNC images of arterial phase(VNCart)and venous phase(VNCven)were generated on AW4.7 workstation.Volume CT dose index(CTDIvol)and dose length product(DLP)were recorded respectively.In a double-blind manner,two physicians graded the severity of each patient's emphysema according to the Fleischner Society's emphysema visual classification system.The"digital lung"detection and analysis platform was used to quantitatively measure emphysema at three thresholds(-950 HU,-930 HU and-910 HU),and the difference in meas-urement results between VNC images and TNC images was compared.Quantitative differences in low attenuation volume(LAV),percentage of low attenuation area(LAA%)and mean lung density(MLD)at the-950 HU threshold were compared using Bland-Altman plots.Results Using TNC images as the standard,there was no significant difference in the results of the visual classifica-tion evaluation of emphysema between TNC and VNC images(χ2=2.80,P=0.247).In quantitative measurement,there was no significant difference in total lung volume(TLV)(χ2=3.26,P=0.196)between the three groups images.Compared to TNC ima-ges,there were no statistically significant differences in LAV,LAA%and MLD of VNCven images at 15th percentile lung density(Perc 15%)and different thresholds(P>0.05).Compared to the TNC mode,the VNC mode could reduce the effective dose(ED)by approximately 32.6%.Conclusion The use of DECT VNCven images on chest has the potential to replace TNC for the quantitative analysis of emphysema,thereby streamlining scans and reducing radiation dose.

Objective:To evaluate the effectiveness and safety of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with stage 4/M neuroblastoma (NB).Methods:This study was a prospective, single-arm, multicenter clinical trial conducted by Sun Yat-sen Memorial Hospital, Children′s Hospital of Nanjing Medical University, Children′s Hospital, Zhejiang University School of Medicine, the First Affiliated Hospital of Guangxi Medical University, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. From March, 2019 to August, 2023, 25 children with confirmed with stage 4/M NB and received allo-HSCT were enrolled. The patients received either unrelated cord blood transplantation (UCBT) or peripheral blood stem cell transplantation (PBSCT). Conditioning regimens for UCBT was fludarabine+busulfan+cyclophosphamide+topotecan, and for PBSCT was fludarabine+busulfan+melphalan+thiotepa+antithymocyte globulin, respectively. Until the last follow-up date of September, 2023, the overall survival (OS) rate and event free survival (EFS) rate were analyzed to evaluate efficacy. The engraftment rate and transplant-related complications were statistically assessed to evaluate safety. Survival analysis was performed using the Kaplan-Meier method.Results:Of the 25 patients, there were 15 males and 10 females. The age at transplantation was 5.7 (3.8, 7.3) years. The engraft rate was 100%, with recovery time of neutrophil as 15.7 (12.5, 17.0) d, and the recovery time of platelets as 33.5 (18.0, 48.0) d. Seventeen of the 25 children (68%) developed acute graft versus host disease (aGVHD), occurred at 18.0 (13.0, 22.5) d after transplantation, including 13 of grade Ⅲ-Ⅳ cases. The main sites of aGVHD were skin and intestinal tract. After treatment, 13 cases improved, 4 patients developed chronic graft-versus-host disease (cGVHD). After allo-HSCT, 14 children received maintenance therapy. Twenty of the 25 patients survived, the 2-year cumulative OS rate was (80±9)%, and 2-year EFS rate was (56±11)%. Nine cases (36%) relapsed, the time from allo-HSCT to disease relapse was 10.9 (5.5, 16.0) months. Five cases (20%) died. The hematopoietic stem cell transplantation associated mortality rate was 4% (1/25).The 2-year OS rate of patients who had partial remission prior to allo-HSCT was significant lower than those who had complete remission prior to allo-HSCT ((33±25)% vs. 100%, P=0.037). Conclusion:allo-HSCT is an effective treatment for patients with stage 4/M NB.

Objective To evaluate the impact of new-generation snapshot freeze(NG SSF)combined with wide body detector on the image quality and diagnosability of multi-temporal coronary computed tomography angiography(CCTA)in patients with free heart rhythm.Methods A retrospective study was conducted on 40 patients who underwent CT scans in 40％-80％cardiac cycles using Revolution APEX 256 row CT scanner to obtain CCTA scan data.For each original data,images were reconstructed both before and after the NG SSF(referred to as the STD group and the NG SSF group respectively)at the 45％phase,75％phase and the Smart Phase.Two cardiovascular imaging diagnosticians respectively scored the image quality of the three major coronary branches[left anterior descending(LAD),left circumflex(LCX),and right coronary artery(RCA)]on the six groups of CCTA images using a Likert 4-point scale.Kappa test was used to analyze the consistency of image quality evaluation by two radiologists.The rank sum test was used to compare and analyze the difference of image quality between the two groups.Results There was good consistency between the two observers in the image quality scores of the six groups of reconstructed CCTA images(Kappa=0.807-1.000).NG SSF significantly improved the image quality of CCTA in all 3 phases(P＜0.05).The reconstructed images in the Smart Phase were superior to those in the 45％and 75％phases both before and after the NG SSF reconstruction,and the differences were statistically significant(P＜0.05).Conclusion NG SSF technology can significantly improves the image quality and diagnosability of CCTA in multi-temporal,and the Smart Phase image quality is generally better for achieving 100％diagnostic success rate with the combina-tion of a 16 cm wide body detector and rapid scanning.Therefore,it has the potential to enhance the confidence in single-phase CCTA scanning and the interpretability under the condition of arrhythmia.

Objective To explore the value of deep learning image reconstruction(DLIR)combined with"three low(low radiation dose,low contrast dose,and low contrast injection rate)techniques"of spectrum CT with low keV in optimizing the image quality of portal vein for liver cirrhosis.Methods Sixty patients with liver cirrhosis who underwent computed tomography portal venography(CTPV)were selected and randomly divided into standard protocol group(group A,n=30)and"three-low"protocol group(group B,n=30).The group A with 120 kVp,contrast dose of 1.4 mL/kg,injection rate of 4.0-5.0 mL/s,and reconstructed 50%adaptive statistical iterative reconstruction-Veo(ASIR-V)image.The group B with 80 kVp/140 kVp double instantaneous switching gemstone spectral imaging(GSI)scan,contrast dose of 1.0 mL/kg,injection rate of 3.0-3.5 mL/s,and reconstructed 40 keV DLIR-M and DLIR-H images.The quality of portal vein images,effective dose(ED),contrast dose and injection rate were compared between the two groups.Results The ED of(4.10±1.56)mSv in group B was lower than that of(7.88±1.08)mSv in group A(P<0.001),and the contrast dose of(67.26±8.74)mL in group B was lower than that of(99.12±8.84)mL in group A(P<0.001).The injection rate of 3.0-3.5 mL/s in group B was reduced by 25%-30%compared with group A.Group B had the greatest contrast-to-noise ratio(CNR)and signal-to-noise ratio(SNR)of portal vein in the 40 keV DLIR-H.The subjective image quality scores were in good agreement between the two physicians(Kappa value>0.75).The subjective DLIR score in group B was higher than that in group A.Conclusion DLIR combined with"three low techniques"spectrum CT with low keV can improve the image quality of portal vein in liver cirrhosis patients.

Objective To investigate the utility of dual-energy computed tomography(DECT)virtual non-contrast(VNC)images instead of true non-contrast(TNC)images in the quantitative analysis of emphysema.Methods A retrospective selection was con-ducted on 59 patients who underwent chest CT plain scan plus dual-phase enhanced scan on APEX-CT.VNC images of arterial phase(VNCart)and venous phase(VNCven)were generated on AW4.7 workstation.Volume CT dose index(CTDIvol)and dose length product(DLP)were recorded respectively.In a double-blind manner,two physicians graded the severity of each patient's emphysema according to the Fleischner Society's emphysema visual classification system.The"digital lung"detection and analysis platform was used to quantitatively measure emphysema at three thresholds(-950 HU,-930 HU and-910 HU),and the difference in meas-urement results between VNC images and TNC images was compared.Quantitative differences in low attenuation volume(LAV),percentage of low attenuation area(LAA%)and mean lung density(MLD)at the-950 HU threshold were compared using Bland-Altman plots.Results Using TNC images as the standard,there was no significant difference in the results of the visual classifica-tion evaluation of emphysema between TNC and VNC images(χ2=2.80,P=0.247).In quantitative measurement,there was no significant difference in total lung volume(TLV)(χ2=3.26,P=0.196)between the three groups images.Compared to TNC ima-ges,there were no statistically significant differences in LAV,LAA%and MLD of VNCven images at 15th percentile lung density(Perc 15%)and different thresholds(P>0.05).Compared to the TNC mode,the VNC mode could reduce the effective dose(ED)by approximately 32.6%.Conclusion The use of DECT VNCven images on chest has the potential to replace TNC for the quantitative analysis of emphysema,thereby streamlining scans and reducing radiation dose.

Objective To explore the value of deep learning image reconstruction(DLIR)algorithm to improve the quality of low keV monochromatic portal vein images of energy spectrum CT.Methods Fifty patients who underwent enhanced upper abdominal energy spectrum CT scan were selected.Mixed-model adaptive statistical iterative reconstruction-Veo(50%ASIR-V)algorithm and high-deep learning image reconstruction(DLIR-H)algorithm were used to obtain monochromatic images at 40-70 keV(with intervals of 10 keV).The CT and standard deviation(SD)values of the portal vein trunk,left and right branches,and erector spinae muscle were measured in the transverse position,and the signal-to-noise ratio(SNR)and portal vein contrast-to-noise ratio(CNR)were calculated for objective evaluation.The portal vein image quality between the two algorithms and different energy was subjectively scored by two physicians.Results In terms of objective evaluation:compared with 50%ASIR-V,the CNR and SNR of portal vein in monochromatic DLIR-H images at the same keV between 40-70 keV energy levels were increased while the SD value was decreased(P＜0.05),and the CT value was unchanged;there was no statistical difference in the magnitude of change in CNR between the two algorithms at different energy levels(P＞0.05);there was a statistically significant difference in the magnitude of change in SNR and SD value(P＜0.05)and the magnitude of change was the largest at 40 keV;comparison between different energy levels of DLIR-H,the CNR and SD value of 40 keV DLIR-H were the highest(P＜0.05),and there was no significant difference in the SNR(P＞0.05).In terms of subjective evaluation:there was no significant difference between the subjective scores of the two algorithms at the same keV from 40-70 keV(P＞0.05),and the two reconstruction algorithms at 40 keV and 50 keV had the highest subjective scores between different keV.Conclusion The DLIR algorithm can reduce the noise of low keV monochromatic images,improve the image quality of portal vein.

Objective To evaluate the impact of new-generation snapshot freeze(NG SSF)combined with wide body detector on the image quality and diagnosability of multi-temporal coronary computed tomography angiography(CCTA)in patients with free heart rhythm.Methods A retrospective study was conducted on 40 patients who underwent CT scans in 40％-80％cardiac cycles using Revolution APEX 256 row CT scanner to obtain CCTA scan data.For each original data,images were reconstructed both before and after the NG SSF(referred to as the STD group and the NG SSF group respectively)at the 45％phase,75％phase and the Smart Phase.Two cardiovascular imaging diagnosticians respectively scored the image quality of the three major coronary branches[left anterior descending(LAD),left circumflex(LCX),and right coronary artery(RCA)]on the six groups of CCTA images using a Likert 4-point scale.Kappa test was used to analyze the consistency of image quality evaluation by two radiologists.The rank sum test was used to compare and analyze the difference of image quality between the two groups.Results There was good consistency between the two observers in the image quality scores of the six groups of reconstructed CCTA images(Kappa=0.807-1.000).NG SSF significantly improved the image quality of CCTA in all 3 phases(P＜0.05).The reconstructed images in the Smart Phase were superior to those in the 45％and 75％phases both before and after the NG SSF reconstruction,and the differences were statistically significant(P＜0.05).Conclusion NG SSF technology can significantly improves the image quality and diagnosability of CCTA in multi-temporal,and the Smart Phase image quality is generally better for achieving 100％diagnostic success rate with the combina-tion of a 16 cm wide body detector and rapid scanning.Therefore,it has the potential to enhance the confidence in single-phase CCTA scanning and the interpretability under the condition of arrhythmia.

Objective To explore the value of deep learning image reconstruction(DLIR)combined with"three low(low radiation dose,low contrast dose,and low contrast injection rate)techniques"of spectrum CT with low keV in optimizing the image quality of portal vein for liver cirrhosis.Methods Sixty patients with liver cirrhosis who underwent computed tomography portal venography(CTPV)were selected and randomly divided into standard protocol group(group A,n=30)and"three-low"protocol group(group B,n=30).The group A with 120 kVp,contrast dose of 1.4 mL/kg,injection rate of 4.0-5.0 mL/s,and reconstructed 50%adaptive statistical iterative reconstruction-Veo(ASIR-V)image.The group B with 80 kVp/140 kVp double instantaneous switching gemstone spectral imaging(GSI)scan,contrast dose of 1.0 mL/kg,injection rate of 3.0-3.5 mL/s,and reconstructed 40 keV DLIR-M and DLIR-H images.The quality of portal vein images,effective dose(ED),contrast dose and injection rate were compared between the two groups.Results The ED of(4.10±1.56)mSv in group B was lower than that of(7.88±1.08)mSv in group A(P<0.001),and the contrast dose of(67.26±8.74)mL in group B was lower than that of(99.12±8.84)mL in group A(P<0.001).The injection rate of 3.0-3.5 mL/s in group B was reduced by 25%-30%compared with group A.Group B had the greatest contrast-to-noise ratio(CNR)and signal-to-noise ratio(SNR)of portal vein in the 40 keV DLIR-H.The subjective image quality scores were in good agreement between the two physicians(Kappa value>0.75).The subjective DLIR score in group B was higher than that in group A.Conclusion DLIR combined with"three low techniques"spectrum CT with low keV can improve the image quality of portal vein in liver cirrhosis patients.

Objective:To evaluate the effectiveness and safety of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in children with stage 4/M neuroblastoma (NB).Methods:This study was a prospective, single-arm, multicenter clinical trial conducted by Sun Yat-sen Memorial Hospital, Children′s Hospital of Nanjing Medical University, Children′s Hospital, Zhejiang University School of Medicine, the First Affiliated Hospital of Guangxi Medical University, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. From March, 2019 to August, 2023, 25 children with confirmed with stage 4/M NB and received allo-HSCT were enrolled. The patients received either unrelated cord blood transplantation (UCBT) or peripheral blood stem cell transplantation (PBSCT). Conditioning regimens for UCBT was fludarabine+busulfan+cyclophosphamide+topotecan, and for PBSCT was fludarabine+busulfan+melphalan+thiotepa+antithymocyte globulin, respectively. Until the last follow-up date of September, 2023, the overall survival (OS) rate and event free survival (EFS) rate were analyzed to evaluate efficacy. The engraftment rate and transplant-related complications were statistically assessed to evaluate safety. Survival analysis was performed using the Kaplan-Meier method.Results:Of the 25 patients, there were 15 males and 10 females. The age at transplantation was 5.7 (3.8, 7.3) years. The engraft rate was 100%, with recovery time of neutrophil as 15.7 (12.5, 17.0) d, and the recovery time of platelets as 33.5 (18.0, 48.0) d. Seventeen of the 25 children (68%) developed acute graft versus host disease (aGVHD), occurred at 18.0 (13.0, 22.5) d after transplantation, including 13 of grade Ⅲ-Ⅳ cases. The main sites of aGVHD were skin and intestinal tract. After treatment, 13 cases improved, 4 patients developed chronic graft-versus-host disease (cGVHD). After allo-HSCT, 14 children received maintenance therapy. Twenty of the 25 patients survived, the 2-year cumulative OS rate was (80±9)%, and 2-year EFS rate was (56±11)%. Nine cases (36%) relapsed, the time from allo-HSCT to disease relapse was 10.9 (5.5, 16.0) months. Five cases (20%) died. The hematopoietic stem cell transplantation associated mortality rate was 4% (1/25).The 2-year OS rate of patients who had partial remission prior to allo-HSCT was significant lower than those who had complete remission prior to allo-HSCT ((33±25)% vs. 100%, P=0.037). Conclusion:allo-HSCT is an effective treatment for patients with stage 4/M NB.