Objective:To investigate impacts of a deep learning image reconstruction (DLIR) algorithm on image quality of lower extremity CTA with low kVp and reverse flow direction scanning.Methods:From January 2021 to March 2021, fifty patients with suspected lower extremities diseases and received lower extremity CTA with low kVp and reverse flow direction scanning in Union Hospital affiliated to Fujian Medical University were retrospectively collected in this study. Six groups of CT images were reconstructed at the thickness of 0.625 mm using two algorithms including ASIR-V of three blending ratios (ASIR-V 20%, ASIR-V 50% and ASIR-V 80%) and DLIR of three strengths (DLIR-H, DLIR-M and DLIR-L). Regions of interest (ROIs) were placed on proximal abdominal aorta (AA), distal AA, left and right common iliac arteries, left and right femoral arteries (upper segment), left and right superficial femoral arteries (middle segment), left and right popliteal arteries. The CT value and SD value were measured for each group; the signal-noise ratio (SNR) and contrast-noise ratio (CNR) were calculated. The lower extremity CTA was divided into four segments, and the subjective evaluation was independently performed on noise and sharpness using 4 points scales by two radiologists. One-way analysis of variance was utilized to evaluate the differences in subjective scoring and objective parameters among the six groups.Results:For all arteries segments, with the increase of blending ratios for ASIR-V and reconstruction strength of DLIR, the SD values were reduced while SNR and CNR were increased (all P<0.05). Among the six groups, DLIR-H and ASIR-V80% images had lowest SD as well as highest SNR and CNR (all P<0.05). In comparison to ASIR-V20% and ASIR-V50% images, DLIR-H images showed lower SD, higher SNR and CNR values (all P<0.05). There were no statistical differences between ASIR-V80% and DLIR-H images in SD, SNR and CNR values (all P>0.05). Subjective scoring results showed that the DLIR-H images displayed the best noise performance for the entire lower extremity arteries from AA to the foot artery, and the sharpness scores of DLIR-H images were also significantly higher than ASIR-V80% (all P<0.05). Conclusion:DLIR can significantly reduce the image noise and improve the image quality in CTA for abdominal aorta to lower extremity arteries. DLIR-H showed the greatest noise reduction ability and the best effect balancing noise and sharpness, providing highest image quality.

Objective: To evaluate the application of laplacian-regularized mean apparent propagator (MAPL)-MRI to brain glioma-induced corticospinal tract (CST) injury. Materials and Methods: This study included 20 patients with glioma adjacent to the CST pathway who had undergone structural and diffusion MRI. The entire CSTs of the affected and healthy sides were reconstructed, and the peritumoral CSTs were manually segmented. The morphological characteristics of the CST (track number, average length, volume, displacement of the affected CST) were examined and the diffusion parameter values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), mean squared displacement (MSD), q-space inverse variance (QIV), returnto-origin probability (RTOP), return-to-axis probabilities (RTAP), and return-to-plane probabilities (RTPP) along the entire and peritumoral CSTs, were calculated. The entire and peritumoral CST characteristics of the affected and healthy sides as well as those relative CST characteristics of the patients with motor weakness and normal motor function were compared. Results: The track number, volume, MD, RD, MSD, QIV, RTAP, RTOP, and RTPP of the entire and peritumoral CSTs changed significantly for the affected side, whereas the AD and FA changed significantly only in the peritumoral CST (p < 0.05). In patients with motor weakness, the relative MSD of the entire CST, QIV of the entire and peritumoral CSTs, and the AD, MD, RD of the peritumoral CST were significantly higher, whereas the RTPP of the entire and peritumoral CSTs and the RTOP of the peritumoral CST were significantly lower than those in patients with normal motor function (p < 0.05 for all). In contrast, no significant changes were found in the CST morphological characteristics, FA, or RTAP (p > 0.05 for all). Conclusion MAPL-MRI is an effective approach for evaluating microstructural changes after CST injury. Its sensitivity may improve when using the peritumoral CST features.

Objective: To evaluate the application of laplacian-regularized mean apparent propagator (MAPL)-MRI to brain glioma-induced corticospinal tract (CST) injury. Materials and Methods: This study included 20 patients with glioma adjacent to the CST pathway who had undergone structural and diffusion MRI. The entire CSTs of the affected and healthy sides were reconstructed, and the peritumoral CSTs were manually segmented. The morphological characteristics of the CST (track number, average length, volume, displacement of the affected CST) were examined and the diffusion parameter values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), mean squared displacement (MSD), q-space inverse variance (QIV), returnto-origin probability (RTOP), return-to-axis probabilities (RTAP), and return-to-plane probabilities (RTPP) along the entire and peritumoral CSTs, were calculated. The entire and peritumoral CST characteristics of the affected and healthy sides as well as those relative CST characteristics of the patients with motor weakness and normal motor function were compared. Results: The track number, volume, MD, RD, MSD, QIV, RTAP, RTOP, and RTPP of the entire and peritumoral CSTs changed significantly for the affected side, whereas the AD and FA changed significantly only in the peritumoral CST (p < 0.05). In patients with motor weakness, the relative MSD of the entire CST, QIV of the entire and peritumoral CSTs, and the AD, MD, RD of the peritumoral CST were significantly higher, whereas the RTPP of the entire and peritumoral CSTs and the RTOP of the peritumoral CST were significantly lower than those in patients with normal motor function (p < 0.05 for all). In contrast, no significant changes were found in the CST morphological characteristics, FA, or RTAP (p > 0.05 for all). Conclusion MAPL-MRI is an effective approach for evaluating microstructural changes after CST injury. Its sensitivity may improve when using the peritumoral CST features.

Objective:To explore the technical advantages of MR cholangiopancreatography (MRCP) with single breath holding high parallel acquisition factor 3-D variable flip angle fast spin echo (3D-SPACE) sequence.Methods:From November 2018 to March 2019, 75 patients who underwent MRCP examination in our hospital were prospectively enrolled, with single breath holding high parallel acquisition factor 3D-SPACE sequence and free breathing navigation gated 3D-SPACE sequence. Three experienced radiologists scored the overall image quality, artifacts, CBD visibility, left and right hepatic ducts, right anterior and posterior branches, second and third branches, main pancreatic duct and gallbladder duct with four scales. Paired t test was used for statistical analysis. Results:The scanning time of single breath holding method (18 s) was significantly shorter than that of free breathing diaphragm navigation method［264（226，313）s］, and the difference between the two methods was statistically significant ( Z=-7.520， P<0.001). The SNR, CR and CNR (8.31±4.23, 0.92±0.30, 11.46±5.77) of single breath holding method were lower than those of free breathing diaphragm navigation method (11.23±5.70, 0.93±0.38, 15.06±7.37), and the differences between the two methods were also statistically significant ( t=4.378, 3.429, 4.063, P<0.05). The overall image quality, artifact, the CBD, left and right hepatic duct, right anterior and posterior branchs, the second and third branches, main pancreatic duct and cystic duct of single breath holding method were higher than those of free breathing diaphragm navigation method, and the differences between the two methods were statistically significant ( P<0.001). Conclusions:Compared with the free breathing diaphragm navigation gated 3D-SPACE MRCP imaging method, the single breath holding high parallel acquisition factor 3D-SPACE MRCP imaging method has less artifacts and examination time, but higher visibility to pancreaticobiliary tree and work efficiency, which is worthy of further promotion.

Objective: To investigate the differences of gemstone spectral curve and CT value of gastric cancer with different pathological types and differentiation degrees. Methods: 91 cases of preoperative gemstone CT images with gastric cancer were collected, including 24 cases of mucinous carcinoma, 67 cases of non-mucinous carcinoma, 16 cases of signet ring cell carcinoma, 8 cases of mucinous adenocarcinoma, 32 cases of moderately differentiated adenocarcinoma and 35 cases of poorly differentiated adenocarcinoma. Gemstone CT spectral imaging was performed preoperatively, and the spectral curve of the lesion in venous phase was obtained by using GSI Viewer software, the slope of the curve was calculated, and 11 monoenergetic CT values of 40~140 keV (10 keV interval) were measured. The gemstone spectral curves and CT values of gastric cancer with different pathological types and differentiation degrees are compared. Results: The curve slopes of non-mucinous carcinoma, signet ring cell carcinoma and poorly differentiated adenocarcinoma were -1.92±0.53, -1.73±0.37 and -2.14±0.54, respectively. The absolute values were higher than those of mucinous carcinoma (-1.45±0.54), mucinous adenocarcinoma (-0.90±0.34) and moderately differentiated adenocarcinoma (-1.67±0.41), and the differences were all statistically significant (P<0.05). There were significant differences in monoenergetic CT values between mucinous and non-mucinous carcinomas at 40-140 keV (all P<0.05). The former was lower than the latter in different degrees, and the lower the energy, the greater the difference was. There were significant differences in monoenergetic CT values between signet ring cell carcinoma and mucinous adenocarcinoma at 40-100 keV (all P<0.05); monoenergetic CT values between poorly differentiated adenocarcinoma and moderately differentiated adenocarcinoma at 40-90 keV showed statistically significant differences (P<0.05). Conclusions Gastric cancer with different pathological types and differentiation degrees have their characteristic spectral curves in venous phase, and the monoenergetic CT values are significantly different at low energy. The spectral curve of gemstone CT may be helpful to evaluate the pathological type and differentiation degree of gastric cancer before operation.

Objective To investigate the differences of gemstone spectral curve and CT value of gastric cancer with different pathological types and differentiation degrees. Methods 91 cases of preoperative gemstone CT images with gastric cancer were collected, including 24 cases of mucinous carcinoma, 67 cases of non?mucinous carcinoma, 16 cases of signet ring cell carcinoma, 8 cases of mucinous adenocarcinoma, 32 cases of moderately differentiated adenocarcinoma and 35 cases of poorly differentiated adenocarcinoma. Gemstone CT spectral imaging was performed preoperatively, and the spectral curve of the lesion in venous phase was obtained by using GSI Viewer software, the slope of the curve was calculated, and 11 monoenergetic CT values of 40～140 keV (10 keV interval) were measured. The gemstone spectral curves and CT values of gastric cancer with different pathological types and differentiation degrees are compared. Results The curve slopes of non?mucinous carcinoma, signet ring cell carcinoma and poorly differentiated adenocarcinoma were －1.92±0.53,－1.73±0.37 and －2.14±0.54, respectively. The absolute values were higher than those of mucinous carcinoma (－1.45±0.54), mucinous adenocarcinoma (－0.90± 0.34) and moderately differentiated adenocarcinoma (－1.67±0.41), and the differences were all statistically significant (P＜0.05). There were significant differences in monoenergetic CT values between mucinous and non?mucinous carcinomas at 40?140 keV ( all P＜0.05). The former was lower than the latter in different degrees, and the lower the energy, the greater the difference was. There were significant differences in monoenergetic CT values between signet ring cell carcinoma and mucinous adenocarcinoma at 40?100 keV (all P＜0.05); monoenergetic CT values between poorly differentiated adenocarcinoma and moderately differentiated adenocarcinoma at 40?90 keV showed statistically significant differences ( P ＜ 0. 05 ). Conclusions Gastric cancer with different pathological types and differentiation degrees have their characteristic spectral curves in venous phase, and the monoenergetic CT values are significantly different at low energy. The spectral curve of gemstone CT may be helpful to evaluate the pathological type and differentiation degree of gastric cancer before operation.

Objective To investigate the differences of gemstone spectral curve and CT value of gastric cancer with different pathological types and differentiation degrees. Methods 91 cases of preoperative gemstone CT images with gastric cancer were collected, including 24 cases of mucinous carcinoma, 67 cases of non?mucinous carcinoma, 16 cases of signet ring cell carcinoma, 8 cases of mucinous adenocarcinoma, 32 cases of moderately differentiated adenocarcinoma and 35 cases of poorly differentiated adenocarcinoma. Gemstone CT spectral imaging was performed preoperatively, and the spectral curve of the lesion in venous phase was obtained by using GSI Viewer software, the slope of the curve was calculated, and 11 monoenergetic CT values of 40～140 keV (10 keV interval) were measured. The gemstone spectral curves and CT values of gastric cancer with different pathological types and differentiation degrees are compared. Results The curve slopes of non?mucinous carcinoma, signet ring cell carcinoma and poorly differentiated adenocarcinoma were －1.92±0.53,－1.73±0.37 and －2.14±0.54, respectively. The absolute values were higher than those of mucinous carcinoma (－1.45±0.54), mucinous adenocarcinoma (－0.90± 0.34) and moderately differentiated adenocarcinoma (－1.67±0.41), and the differences were all statistically significant (P＜0.05). There were significant differences in monoenergetic CT values between mucinous and non?mucinous carcinomas at 40?140 keV ( all P＜0.05). The former was lower than the latter in different degrees, and the lower the energy, the greater the difference was. There were significant differences in monoenergetic CT values between signet ring cell carcinoma and mucinous adenocarcinoma at 40?100 keV (all P＜0.05); monoenergetic CT values between poorly differentiated adenocarcinoma and moderately differentiated adenocarcinoma at 40?90 keV showed statistically significant differences ( P ＜ 0. 05 ). Conclusions Gastric cancer with different pathological types and differentiation degrees have their characteristic spectral curves in venous phase, and the monoenergetic CT values are significantly different at low energy. The spectral curve of gemstone CT may be helpful to evaluate the pathological type and differentiation degree of gastric cancer before operation.

Objective To investigate the value of wide-detector Revolution CTA with 70 kV tube voltage and prospective ECG-gated technique in diagnosis of congenital heart disease (CHD) in infants and children.Methods Forty-five infants and children with complicated CHD underwent echocardiography and wide-detector Revolution CTA.According to the sur gical findings,the diagnostic efficiency of Revolution CTA and echocardiography were calculated and compared.The radiation effective dose (ED) and iodine dose were calculated.The quality of CT images was also evaluated.Results There were 25 separate cardiovascular anomalies including 6 congenital cardiac structure anomalies and 19 congenital extracardiac vascular anomalies.For congenital extracardiac vascular anomalies,there was significant difference of diagnostic accuracy and the detectable rate between CTA (99.77％ [853/855],97.73％ [86/88]) and echocardiography (98.71％ [844/855],88.64％ [78/88];x2 =6.28,5.72,both P＜0.05).The average of ED was (0.20±0.05)mSv and the mean iodine dose was (2.06± 1.09)g.All CT images were qualified for diagnosis.Conclusion The wide-detector Revolution CTA,with the prospective ECG-gated technique and 70 kV tube voltage,can provide high accuracy for assessment of CHD in infants and children,which can keep good image quality,with the low radiation dose.

Objective To investigate the clinical value of gemstone spectral imaging (GSI) associated with patient-based low dose of contrast medium protocol in carotid CTA. Methods One hundred and twenty patients who were suspected with stenotic carotid artery or carotid plaque were prospectively enrolled in the study. All of them were divide into two groups by random number table. Group A (routine group): 60 were scanned with 120 kVp after the administration of moderate-concentration CM(320 mg/ml) with 5 ml/s injection velocity, Group B (low dose group):60 were scanned with GSI which was reconstructed using 50%ASiR after the administration of the same CM with 3 ml/s injection velocity. The contrast dose [(test bolus peak time +2 s – 5 s) × injection velocity] was calculated. Images of the two groups were compared in terms of arterial attenuation, signal-noise-ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality (IQ) score. The value of CT dose index volume (CTDIvol), dose length product (DLP) and effective dose (ED) was recorded, respectively. Data were analyzed by using independent samples t test or Mann-Whitney U test. Results The mean attenuation, noise, SNR, CNR, subjective image quality score, contrast dose, CTDIvol, DLP and ED of routine group was (363 ± 56)HU, (13 ± 4)HU, 30 ± 10, 38±13, 3.0 score, (69 ± 13) ml, 13.61 mGy,527 mGy · cm and 3.11 mSv, respectively. The above variables of low-dose-group was (378 ± 69) HU, (9 ± 4)HU, 48 ± 19, 62 ± 24, 2.0 score,(49 ± 7)ml, 12.72 mGy, 478 mGy · cm and 2.82 mSv, respectively. The mean attenuation and subjective IQ score of carotid artery had no significant differences statistically between two groups (P>0.05), respectively. The noise, SNR, CNR, contrast dose, CTDIvol, DLP and ED had significant differences statistically between two groups (P<0.05), respectively. Conclusion Compared with 120 kVp protocol, the use of GSI associated with patient-based low dose of contrast medium protocol in carotid CTA could provide equivalent image quality and higher SNR and CNR of carotid artery with a smaller amount of iodine and a lower radiation dose.

Objective To evaluate spectral CT imaging in characterizing the pathological type and the differentiation of gastric cancer.Methods Ninety-one patients diagnosed of gastric cancer were retrospectively analyzed.Patients were all underwent triple-phase enhanced scan using single source dualenergy CT on gemstone spectral imaging(GSI) mode.Three types of images were reconstructed for analysis:the water concentration (WC),iodine concentration (IC),and normalized iodine concentration (NIC).The patients were divided into groups of mucinous carcinoma (MUC),including mucinous adenocarcinoma and signet ring cell carcinoma,and non-mucinous gastric carcinoma (non-MUC).Independent-samples t test was used for statistical analysis.Results There were 24 patients of MUC and 67 patients of non-MUC.The IC and NIC of the non-MUC were significantly higher than the MUC in vein phase (VP) and in parenchymal phase (PP) [(21.33 ±6.31) × 100 vs (16.94 ±6.13) × 100 μg/ml,0.55 ±0.17 vs 0.42 ±0.14 in VP,and(20.65 ±5.49) × 100 vs (18.07 ±4.51) × 100 μg/ml,0.72 ±0.20 vs 0.57 ±0.12 in PP,respectively t =-2.948,-3.362,-2.261,-4.326,P ＜0.05].The IC and NIC of the signet ring cell carcinoma were statistically higher than those of the mucinous adenocarcinoma [(19.36 ± 4.75) × 100 vs (12.10 ±5.92) ×100μg/ml,0.49 ± 0.09 vs0.28±0.11 in VP,and (19.88±3.28) ×100 vs (14.45±4.62) ×100 μg/ml,0.63 ±0.08 vs 0.47 ±0.11 in PP,respectively t =3.253,5.180,3.339,3.850,P ＜0.01].For the poorly differentiated and well /moderately differentiated adenocarcinoma,the IC and NIC of the former were higher than those of the latter in VP and PP [(23.48 ±6.49) × 100 vs (18.98 ±5.26) × 100 μg/ml,0.61±0.16vs0.48±0.15 in VP,and (22.95±5.51) ×100 vs (18.28±4.47) ×100 μg/ml,0.81 ± 0.21 vs 0.63 ± 0.15 in PP,respectively t =3.098,3.249,3.766,4.117,P ＜ 0.01].The between-group differences of WC,IC and NIC in artery phase were no significant (P ＞ 0.05).Conclusions Different pathological types could determine different IC.The spectral CT imaging may be helpful for characterizing the pathological type of gastric cancer.