Objective:To explore the application value of wide detector multi-slice spiral CT target scanning technique in the preoperative evaluation of pancreatic cancer.Methods:The clinical data of 22 patients with pancreatic cancer who underwent pancreatic arterial contrast enhanced CT scanning and were diagnosed by pathology in the First Affiliated Hospital of Naval Medical University from September 2019 to October 2019 were analyzed retrospectively. The CT phantom experiment was carried out on the international standard phantom CATPHON500. By changing the scanning radiation dose, scanning mode and scanning field of view, the spatial resolution and density resolution of the image were compared and analyzed. The target scan technical parameters obtained from the experiment were applied to the late arterial phase of MDCT enhanced scan in 22 patients with pancreatic cancer. Executive current, volume scanning mode and small scanning field were used for scanning. The attenuation value (CT value) and noise value (SD value) of pancreatic cancer tissue and normal pancreatic tissue were measured at different phases, the attenuation difference and contrast signal-to-noise ratio (CNR) of the two tissues were calculated, the contrast difference between the two tissues was evaluated, and the CT values of celiac trunk, renal artery and vein, superior mesenteric artery and vein, splenic vein and portal vein were measured, and the display of tumor tissue and peripancreatic important vessels was evaluated.Results:In the phantom experiment, under the condition of the same radiation dose, the image quality of the volume scan mode was better than that of the spiral scan mode (1%@4 mm versus 1%@9 mm at 5 mGy and 1%@2 mm versus 1%@6 mm at 25 mGy). In comparison between pancreatic tumor and pancreatic tissue, the enhancement process of pancreatic tumor tissue was increased at first and then decreased, while that of pancreatic tumor tissue was slightly enhanced. The attenuation difference between pancreatic tissue and tumor tissue and CNR also increased at first and then decreased, reaching the maximum at the late arterial stage [(91.96±29.29)HU, 8.60±5.71]. The differences between each phase were statistically significant ( F values were 47.20 and 19.80 respectively, all P values <0.05). The evaluation of vascular variation and invasion showed that a better arterial phase image could be obtained on the late arterial target scan images, while taking into account the display of splenic vein, mesenteric vein and portal vein. Conclusions:The wide detector MDCT target scanning technique can improve the spatial resolution and density resolution of the image, greatly improve the contrast between tumor tissue and peripancreatic tissue and blood vessels, and provide more accurate tumor staging and resectability evaluation information for preoperative evaluation of pancreatic cancer.

Objective:To evaluate the safety and efficacy of bortezomib plus highdose melphalan (L-phenylalanine nitrogen mustard) (Bor-HDM) pretreatment regimen for multiple myeloma (MM) with autologous hematopoietic stem cell transplantation (ASCT).Methods:From August 2008 to December 2021, the relevant clinical data were retrospectively reviewed for 58 MM patients undergoing MM transplantation.The conditioning regimens were Bor-HDM (n=36) and HDM (n=22). Non-hematopoietic adverse reactions, hematopoietic reconstruction time, remission rate post-ASCT and minimal negative rate of residual disease (MRD) on flow cytometry within 3 months post-ASCT and survivals were analyzed.Results:In Bor-HDM and HDM groups, median time of neutrophil engraftment was 12(8-30) and 11(8-29) day and median time of platelet reconstitution 16(8-33) and 16(7-32) day respectively.There was no significant inter-group difference ( P=0.890, P=0.638). In Bor-HDM group, the most common non-hematological adverse reactions were nausea (n=21, 58.0%) and diarrhea (n=11, 30.6%). There was no transplant-related death.Complete remission (CR) rate was (25/36, 69.4%) versus (9/22, 40.9%). The inter-group difference was statistically significant ( P=0.032). Median follow-up period was 29.0(2.0-91.0) vs. 20.5(5.0-114.0) month, 3-year progression-free survival(PFS)62.1% vs. 39.7% and 3-year overall survival(OS) 83.8% vs. 62.5%.There were relapse (n=10 vs.10) and death (n=6 vs. 7). Median PFS in Bor-HDM and HDM groups was non-attained and 27 months( P=0.047) and median OS time non-attained and 40 months respectively ( P=0.282). Multivariate analysis revealed that CR was an independent risk factor for PFS ( HR=28.896, 95% CI: 6.130-136.198, P<0.001). Non-CR was an independent risk factor for OS ( HR=3.843, 95% CI: 1.334-11.071, P=0.013; HR=28.595, 95% CI: 6.273-130.355, P<0.001). Conclusions:Bor-HDM pretreatment regimen of ASCT is both safe and efficacious for MM patients.

This study aims to explore the effect of aortic sinus diameter on aortic valve opening and closing performance in the case of no obvious disease of aortic valve and annulus and continuous dilation of aortic root. A total of 25 three-dimensional aortic root models with different aortic sinus and root diameters were constructed according to the size of clinical surgical guidance. The valve sinus diameter S is set to 32, 36, 40, 44 and 48 mm, respectively, and the aortic root diameter is set to 26, 27, 28, 29 and 30 mm, respectively. Through the structural mechanics calculation with the finite element software, the maximum stress, valve orifice area, contact force and other parameters of the model are analyzed to evaluate the valve opening and closing performance under the dilated state. The study found that aortic valve stenosis occurs when the = 32 mm, = 26, 27 mm and = 36 mm, = 26 mm. Aortic regurgitation occurs when the = 32, 36 and 40 mm, = 30 mm and = 44, 48 mm, = 29, 30 mm. The other 15 models had normal valve movement. The results showed that the size of the aortic sinus affected the opening and closing performance of the aortic valve. The smaller sinus diameter adapted with the larger root diameter and the larger sinus diameter adapted with the smaller root diameter. When the sinus diameter is 40 mm, the mechanical performance of the valve are good and it can well adapt with the relatively large range of aortic root dilation.
Aorta ; anatomy & histology ; Aortic Valve ; physiology ; Aortic Valve Insufficiency ; physiopathology ; Aortic Valve Stenosis ; physiopathology ; Humans

Objective To explore the biomechanical mechanism of aortic insufficiency (AI) after single aortic valve replacement (SAVR) in children and propose the corresponding countermeasures. Methods The idealized aortic valve model and postoperative growth model were constructed. By changing the length of leaflet free edge, leaflet height as well as improving the design with a concave structure, the effects of different structure dimensions on movement synchronization and closing performance of the aortic valve after surgery were compared. Results The closure of the replacement leaflet lagged behind the autologous leaflet, which fitted 2 mm below free edge of the replacement leaflet. AI occurred 6 years after operation. Increasing leaflet height could not improve the postoperative effect and would increase the maximum stress of the leaflet. Increasing free edge length by 10% could improve the postoperative outcomes, while increasing free edge length by 15% would cause the leaflet to be too long, hence resulting in a poor fit of the aortic valve. Compared with the traditional structure, the concave structure was more beneficial for closing performance of the aortic valve, and it could effectively reduce the maximum stress by 20% with the best effect. Conclusions The leaflet movement will be out of synchronization after SAVR, the point of convergence will be shifted, and AI will appear 6 years after surgery. It is recommended to use a concave structure with free edge length increased by 10%, while increasing leaflet height is not recommended.