Objective To evaluate the factors affecting urinary stone detection rate using virtual unenhanced(VUE)images obtained from triphasic dual-energy CT urography(DECTU)based on Logistic regression analysis.Methods For this study,150 patients who had suspected urinary stone and underwent triphasic DECTU were included.The true unenhanced(TUE)images were reconstructed as 120 kVp-like images,and VUE images at the portal venous phase[VUE(VP)]and excretory phase[VUE(EP)]were obtained using iodine removal technique from portal venous and excretory phase DECTU images,respectively.Two readers independently evaluated the above three types of images,and recorded the number of urinary stones,their anatomical locations,and whether there was residual iodine on the VUE images.Stone size and CT number were recorded only on the TUE images.Stone size,CT number,anatomical location,and iodine contrast agent were included in univariate and multivariate Logistic regression analyses to evaluate the factors affecting urinary stone detection rate using VUE images.Thresholds for detecting urinary stones on VUE images were determined using receiver operating characteristics(ROC)analysis.Results We detected 304 stones on TUE images,while the detection rates were 92.4％and 71.4％when using VUE(VP)and VUE(EP)images,respectively.Stone size and CT number were important factors influencing urinary stone detection rate using VUE(VP)and VUE(EP)images(P＜0.01).The area under curve(AUC)of using stone size and CT number for detecting stones using the VUE(VP)images was up to 0.96,and as threshold values,stones with size larger than 3.52 mm and CT number greater than 469 HU were found to have high accuracy.However,the AUC decreased to 0.88 when we combined stone size,CT number and anatomical location using the VUE(EP)images.In addition,different contrast agents did not affect the detection rate of stones on the VUE(EP)images(P=0.57).The stone detection rate in the kidney was significantly lower than those on the VUE(EP)images(P＜0.001).Conclusion VUE(VP)images provide better stone detection.Stone size and CT number have significant impacts on the stone detection rate using VUE images.The lower stone detection rate in the kidney on the VUE(EP)images is related to the residual iodine.

Objective To investigate the value of abdominal aortic combined with routine one-stop triple rule-out computed tomography angiography(TRO-CTA)in the examination of patients with acute chest pain.Methods A total of 1 482 patients with nontraumatic chest pain were included in this retrospective study.Of them 414 patients underwent the conventional TRO-CTA scanning while 1 068 patients underwent TRO-CTA that included the abdominal aorta(TRO-CTAwAA)under the request of clinicians.All scanning parameters were the same,except the scanning range for the third phase in TRO-CTA:conventional TRO-CTA covered only the thoracic aorta,while TRO-CTAwAA extended to the entire aorta.Patient etiology was investigated and the detection rates of major vessel abnormalities(aortic dissection,aneurysm,penetrating ulcer,intramural hematoma,vascular occlusion,and thrombosis)between the two groups was compared using chi square tests.The radiation dose(CTDIvol and DLP)and scanning time between the two groups were compared using analysis of variance(ANOVA).Results The TRO-CTAwAA had significantly higher detection rate of major artery abnormalities than the TRO-CTA group(35.1％vs.4.8％,P＜0.001).In the TRO-CTAwAA group,26.5％of the vascular anomalies were detected in both the thoracic and abdominal aortas,and another 8.6％were seen only in the abdominal aorta.With regard to the radiation dose between the two groups,the total DLP was significantly higher in the TRO-CTAwAA group than in the conventional TRO-CTA group(P＜0.001).The two groups did not significantly differ in scanning time(P=0.410).Conclusion TRO-CTA with scan range including the abdominal aorta significantly improves the detection rate for major vessel abnormalities in patients with chest pain without increasing the examination process.

Objective:To investigate the practicality of TrueFidelity deep learning reconstruction algorithm in low-dose abdominal and pelvic CT angiography (CTA).Methods:The patients who required abdominal and pelvic CTA were prospectively included at the First Affiliated Hospital of Xi′an Jiaotong University from June 2020 to March 2021. All patients underwent low-dose CTA with a tube voltage of 80 kV and smart tube current modulation (100-720 mA). Images were reconstructed using the traditional FBP, adaptive statistical iterative reconstruction with a strength of 50% (ASIR-V 50%), TrueFidelity with medium (TF-M) and high (TF-H) strength. The CT value and standard deviation (SD value) of the abdominal aorta, psoas major muscle and subcutaneous fat in the same layer were measured, signal to noise ratio (SNR) and contrast to noise ratio (CNR) were calculated. We also introduced the measurement of skewness of CT value in psoas major muscle with uniform density. The above indexes of the four groups of reconstructed images were compared. A 5-point scoring method was used to evaluate the granularity, fuzziness and beam-hardening artifacts of all images. Objective measurement indicators, such as CT values, were tested by repeated measure ANOVA with the Bonferroni post hoc test.Results:There were forty-six patients in the study. The volume CT dose index of the scan was low at (1.09±0.31)mGy. There was no significant difference in CT values of vessels and muscles between the four groups ( P>0.05), but there was a significant difference in SD value( P<0.001). The SD value of the FBP group was the largest and that of the TF-H group was the smallest. The difference between SNR and CNR was statistically significant ( P<0.001), and the overall trend was opposite to that of the SD value. There was no significant difference in the skewness between the four groups. The granularity score of the FBP group was the largest, that of the TF-H group was the smallest, and there was a significant difference among the four groups. The score of fuzziness in the TF-H group was slightly higher than that in the other three groups, but there was no significant difference. The beam-hardening artifact score of FBP and ASIR-V 50% group was the worst, and the TF-H group was the best ( P<0.001). Conclusions:Compared with FBP and ASIR-V, TrueFidelity reconstruction algorithm provides better image quality (comprehensively considering image noise, fuzziness, uniformity, and hardening artifacts) in low-dose CT scanning of abdominal and pelvic vessels, and TF-H has the best image quality.

Objective To compare the perioperative efficacy and safety of da Vinci robot-assisted thoracoscopic surgery (RATS) for treatment of anterior mediastinal tumors through subxiphoid versus lateral thoracic approaches under the laryngeal mask anesthesia. Methods We retrospectively analyzed the clinical data of 102 patients with anterior-mediastinal tumors treated by RATS under laryngeal mask anesthesia completed by the same operator. Forty-five patients underwent the subxiphoid approach (subxiphoid group), and 57 patients were treated with the lateral thoracic approach (lateral thoracic group). The operating time, intraoperative bleeding, and total postoperative drainage volume in the two groups were compared and analyzed. Results All patients successfully completed resection of the anterior mediastinal tumor without the occurrence of perioperative death. In terms of total postoperative drainage volume, postoperative drainage time, postoperative hospital stay, and VAS pain on postoperative days 2 and 3, the subxiphoid group was more advantages (P < 0.05). No statistically significant difference was found between the two groups in terms of operative time, docking time, total operative time, intraoperative bleeding volume, postoperative day 1 VAS pain score, or postoperative complications (P > 0.05). Conclusion The subxiphoid approach of RATS is safe and feasible for resection of anterior mediastinal tumors. Compared with the lateral thoracic approach, the subxiphoid approach has advantages in terms of rapid postoperative recovery and postoperative pain.

【Objective】 To investigate the value of deep learning image reconstruction (DLIR) in improving image quality and reducing beam-hardening artifacts of low-dose abdominal CT. 【Methods】 For this study we prospectively enrolled 26 patients (14 males and 12 females, mean age of 60.35±10.89 years old) who underwent CT urography between October 2019 and June 2020. All the patients underwent conventional-dose unenhanced CT and contrast-enhanced CT in the portal venous phase (noise index of 10; volume computed tomographic dose index: 9.61 mGy) and low-dose CT in the excretory phase(noise index of 23; volume computed tomographic dose index: 2.95 mGy). CT images in the excretory phase were reconstructed using four algorithms: ASiR-V 50%, DLIR-L, DLIR-M, and DLIR-H. Repeated measures ANOVA and Kruskal-Wallis H test were used to compare the quantitative (skewness, noise, SNR, CNR) and qualitative (image quality, noise, beam-hardening artifacts) values among the four image groups. Post hoc comparisons were performed using Bonferroni test. 【Results】 In either quantitative or qualitative evaluation, the SNR, CNR, overall image quality score, and noise of DLIR images were similar or better than ASiR-V 50%. In addition, the SNR, CNR, and overall image quality scores increased as the DLIR weight increased, while the noise decreased. There was no statistically significant difference in the distortion artifacts (P=0.776) and contrast-induced beam-hardening artifacts (P=0.881) scores among these groups. 【Conclusion】 Compared with the ASiR-V 50% algorithm, DLIR algorithm, especially DLIR-M and DLIR-H, can significantly improve the image quality of low-dose abdominal CT, but has limitations in reducing contrast-induced beam-hardening artifacts.

Objective:To explore intraoperative assessment of blood supply to the femoral head after femoral neck fracture, and the correlation between the blood supply and postoperative osteonecrosis of the femoral head.Methods:A retrospective analysis was performed of the 63 patients with femoral neck fracture who had been treated at Department of Orthopaedic Trauma and Microsurgery, Zhongnan Hospital of Wuhan University by open reduction and internal fixation with hollow compression screws from April 2016 to March 2021. They were 39 males and 24 females with an age of (44.9±13.6) years. There were 42 cases of Garden type Ⅲ and 21 cases of Garden type Ⅳ. Time from injury to operation was (4.1±2.4) days. After internal fixation, a hole was drilled using a 2.0 mm Kirschner wire at 2.0 cm above the femoral head-neck junction to observe the velocity, color, and characteristics of the blood oozing at the drill hole. The patients were divided into a good oozing group of 51 cases in whom bright red blood oozing was observed within 15 seconds after drilling and a poor oozing group of 12 cases in whom dark red blood oozing was observed beyond 15 seconds after drilling. The incidence of postoperative femoral head necrosis, Harris hip score, and visual analogue scale (VAS) for pain were compared between the 2 groups. Single factor and multi factor analyses were conducted using the Cox regression model to analyze the factors influencing postoperative femoral head necrosis in the patients.Results:The 63 patients were followed up for 24 (18, 36) months. The 2 groups were comparable because there was no significant difference in the preoperative general data between them ( P>0.05). Femoral head necrosis was observed in 3 cases in the good oozing group and in 5 cases in the poor oozing group, showing a significant difference between the 2 groups ( P<0.05). The Harris hip score [90.0 (86.0, 92.0)] and the VAS pain score [1.0 (1.0, 2.0)] at 1 year after surgery in the good oozing group were significantly better than those in the poor oozing group [85.5 (71.3, 88.8) and 2.5 (1.0, 3.8)] ( P<0.05). Multivariate Cox regression analysis showed that Garden type Ⅳ ( HR=6.784, 95% CI: 1.324 to 35.664, P=0.023) and intraoperative poor blood oozing ( HR=10.744, 95% CI: 2.359 to 51.774, P=0.003) were risk factors for femoral head necrosis after cannulated compression screw fixation of fractures of displaced femoral neck ( P<0.05). Conclusions:The blood supply to the femoral head after femoral neck fracture can be directly assessed by drilling a hole in the femoral head after open reduction and internal fixation. Intraoperative poor blood oozing is a risk factor for the femoral head necrosis after cannulated compression screw fixation of fractures of displaced femoral neck.

【Objective】 To explore the value of deep learning reconstruction algorithm (DLIR) in improving image quality of portal vein. 【Methods】 We retrospectively enrolled 32 patients who underwent double-phasic enhanced abdominal CT scanning. Images at the portal venous phase were reconstructed using the 50% adaptive statistical iterative reconstruction (ASIR-V), DLIR at medium (DLIR-M) and high strength (DLIR-H). The CT value and image noise (standard deviation) of the main portal vein, the right portal vein branch, the left portal vein branch, and the paravertebral muscle were measured, and the contrast-noise-ratio (CNR) for vessels were calculated. Moreover, the edge-rising-slope (ERS) of the main portal vein edge was measured to evaluate image spatial resolution. The overall image noise, image contrast, and portal vein branch display were evaluated using a 5-point grading scale and image artifacts using a 4-point grading scare by two experienced radiologists. In addition, we calculated the display rate of small branches of the portal vein in the three reconstruction algorithms. 【Results】 Image noise of the DLIR images in the main portal vein, right branch and left branch was significantly lower than that of ASIR-V 50% images, of which the DLIR-H images had the lowest noise and highest CNR. The ERS of the DLIR images in the main portal vein was significantly higher than that of the ASIR-V 50% images. For qualitative analyses, the DLIR images were significantly better than the ASIR-V 50% ones (P<0.01). In addition, the display rates of small branches of the portal vein in DLIR images were (DLIR-M: 93.75%; DLIR-H: 100%), significantly higher than that of ASIR-V 50% (68.75%). 【Conclusion】 Compared with ASIR-V 50% images, DLIR images can significantly reduce the image noise and improve the spatial resolution of the portal vein and the display rate of small branches of the portal vein.

【Objective】 To assess the effect of reconstruction kernels and window settings on the detection and measurement of pulmonary solid nodules and their measurement variability and repeatability. 【Methods】 We retrospectively recruited 49 patients with pulmonary solid nodules who had undergone low-dose CT scanning. Images were reconstructed using five reconstruction kernels： lung， bone， chest， detail and standard kernels. Two radiologists independently assessed the detection rate， diameter and CT number measurement of nodules under the five kernels and two window settings （lung-window and mediastinal-window）. Bland-Altman plots and relative average deviation （RAD） were used to evaluate the repeatability and variability of nodule diameter and CT number measurement. 【Results】 Seventy-seven nodules were detected on lung-window regardless of reconstruction kernels， while the detection rates （75.3%-98.7%） were significantly different （P<0.001） on the mediastinal-window， with the lung kernel significantly improving the detection of nodules with the diameter below 6 mm. In both display windows， the diameter and CT number measurements among reconstruction kernels were similar except for the lung kernel. The lung-window had better variability in the diameter measurement while mediastinal-window was better in CT number measurement among various reconstruction kernels. Although the variability in the diameter of the nodule on the lung-window and mediastinal-window was similar， there was a significant difference in the variability in the diameter measurement among different reconstruction kernels on the mediastinal-window （P=0.004）. No significant difference in the variability in the CT number measurement was found among the different reconstruction kernels （lung-window P=0.163； mediastinal-window P=0.201）， and the variability in the CT number measurements on the mediastinal-window was smaller than that of the lung-window. Both window displays had acceptable repeatability in diameter and CT number measurement； however， the mediastinal-window was better in CT number measurement. 【Conclusion】 The lung kernel can improve the detection of pulmonary solid nodules below 6 mm， but is limited in the CT number measurement. The lung-window display provides better variability in measuring nodule diameter， while mediastinal-window display is better at measuring CT numbers.

Nanomaterials usually refer to tiny particles with a diameter of 1-100 nm, which often have unique physicochemical properties and are one of the main areas of research interest for development of dental biomaterials. Nano-calcium phosphate modified dental materials have been widely used in pit and fissure sealing, dental resin restoration, tooth adhesion, and root canal sealing. The current research shows that the dental material modified by nano-calcium phosphate has stronger mechanical properties and shows long-term calcium and phosphorus ion release and excellent ion recharging ability, which can promote the remineralization of tooth hard tissue and has good prospects for application. However, it is difficult to accurately simulate the complex environment of the oral cavity. Therefore, the biocompatibility, cytotoxicity and effect of clinical application of nano-calcium phosphate modified dental materials still needs further study. This review summarizes and discusses the recent research progress regarding nano-calcium phosphate modified dental materials in the prevention and treatment of dental pulp diseases.

Objective: To explore and compare the preventive effect of using letrozole and gonadotropin-releasing hormone (GnRH) antagonist during luteal phase of patients at high risk for ovarian hyperstimulation syndrome (OHSS). Methods: A total of 99 infertile women undergoing in vitro fertilization and embryo transfer or intracytoplasmic sperm injection with high risk for OHSS were enrolled in this randomized controlled trial.The letrozole group (n=51) received letrozole of 7.5 mg daily for 3 days;the GnRH antagonist group (n=48) were given cetrorelix of 0.25 mg subcutaneously daily for 3 days. Both groups received support therapy combined with embryo cryopreservation. The incidence of OHSS was surveyed. And the serum concentration of estradiol, LH and progesterone on days 3, 5 and 8 after oocytes retrieval were measured. Results: There were no statistical differences in terms of baseline characteristics of patients and outcomes of controlled ovarian hyperstimulation between the two groups.The incidence of moderate and severe OHSS was found no significantly difference between letrozole group [11.8%(6/51)] and GnRH antagonist group [10.4%(5/48);P>0.05]. The estradiol concentration of the indicated days on days 3,5 and 8 after oocytes retrieval in letrozole group and GnRH antagonist group were (1 417±3 543) versus (15 210±9 921) pmol/L, (1 692±4 330) versus (18 680±11 567) pmol/L, (239±336) versus (3 582±5 427) pmol/L, respectively;compared with GnRH antagonist group, the estradiol level was significantly lower in the letrozole group (all P<0.01). The luteinizing hormone level in the letrozole group were (0.46±0.40), (0.56±0.55)and (0.67±0.58) U/L on days 3,5 and 8 after oocytes retrieval, which were significantly higher than those of GnRH antagonist group [(0.28±0.28), (0.30±0.19) and (0.45±0.37) U/L, respectively; all P<0.05]. There was no obvious differences on progesterone levels between letrozole group and GnRH antagonist group (all P>0.05),and on days 8 after oocytes retrieval,the level of progesterone in each group were significantly lower than those on day 3 and 5 after oocytes retrieval (P<0.05). Conclusion Letrozole has the same efficiency as GnRH antagonist for the prevention of OHSS, faster and cheaper to use, but its efficacy seems not to be related to the suppression of steroidogenic during the luteal phase.