[Effect of closed extension tube on preventing airway leakage during artificial airway clearance].

Objective: To explore the role of closed extension tube in preventing airway leakage during artificial airway clearance. Methods: The test lung was connected with a ventilator for mechanical ventilation. The pressure parameters were set as 16/5, 20/6, 24/7, 28/8, 32/9 and 36/10 cmH2O(1 cmH2O=0.098 kPa), respectively. The circuit was connected with an open extension tube or a closed extension tube. The ventilator was set with different pressure parameters to observe the changes of airway pressure and tidal volume during airway clearance. Results: (1) The pressure parameters were set as 16/5, 20/6, 24/7, 28/8, 32/9 and 36/10 cmH2O, and the airway pressures (in cmH2O) of circuit connected with open extension tube were (15.94±0.27)/(4.81±0.04), (20.09±0.23)/(6.05±0.16), (23.89±0.41)/(6.94±0.06), (27.90±0.22)/(7.71±0.18), (31.92±0.13)/(8.74±0.12)and(35.65±0.31)/(9.72±0.07), respectively.Under the same ventilator pressure parameters, the airway pressures (in cmH2O) of circuit connected with close extension tube were (16.36±0.06)/(4.85±0.04), (20.54±0.26)/(6.44±0.12), (24.36±0.24)/(7.01±0.33), (28.69±0.25)/(8.07±0.08), (32.97±0.33)/(8.93±0.09), (37.34±0.29)/(9.75±0.08), respectively. The airway pressure of circuit connected with open extension tube was lower than that connected with closed extension tube(P<0.05);with the increase of the pressure setting of the ventilator, the difference of the airway pressure between the two extended tubes gradually increased. When the maximum inspiratory pressure of the ventilator was set 36 cmH2O, the difference reached 1.69 cmH2O. (2) The airway pressures (in cmH2O) dropped from (15.94±0.27)/(4.81±0.04), (20.09±0.23)/(6.05±0.16), (23.89±0.41)/(6.94±0.06), (27.90±0.22)/(7.71±0.18), (31.92±0.13)/(8.74±0.12), (35.65±0.31)/(9.72±0.07) to (13.42±0.4)/(3.15±0.14), (16.81±0.6)/(4.30±0.14), (20.22±0.5)/(5.48±0.45), (23.73±1.4)/(6.25±0.22), (24.78±0.7)/(7.13±0.21), (20.83±0.4)/(6.61±0.19)when the suction port of the open extension tube was opened (P<0.05);and the tidal volume (in L) also decreased from 0.328±0.004, 0.580±0.012, 0.621±0.003, 0.626±0.003, 0.615±0.003, 0.603±0.002 to 0.272±0.008, 0.416±0.051, 0.487±0.047, 0.396±0.116, 0.507±0.022, 0.508±0.079, respectively (P<0.05). The decrease of airway pressure and tidal volume gradually increased with the increase of ventilator setting pressure. When the ventilator setting parameter was 36/10 cmH2O, the decrease of airway inspiratory pressure was (14.82±0.51) cmH2O and the maximum reduction of tidal volume was (0.164±0.021)L. (3)The airway pressure (in cmH2O) was increased to(15.70±0.23)/(4.80±0.33), (19.01±0.81)/(5.71±0.34), (22.27±0.62)/(6.85±0.44), (25.35±2.09)/(7.94±0.16), (28.38±0.46)/(8.96±0.23), (33.34±0.71)/(9.71±0.25) when the suction tube was inserted from the suction port of the open extension tube in the open state, and the tidal volume (in L) was increased to 0.340±0.016, 0.563±0.020, 0.571±0.030, 0.556±0.026, 0.514±0.021, 0.512±0.031 as well.The airway pressure and tidal volume of the ventilation circuit were higher than those in the open state, but still lower than those in the closed state. Compared with the closed state of the suction port, the maximum pressure drop and tidal volume decrease were (3.53±0.46) cmH2O and (0.101±0.011) L, respectively. (4) The pressure of the ventilator was set between 16/5 cmH2O to 36/10 cmH2O. The airway pressure (in cmH2O) was decreased from (16.26±0.04)/(4.85±0.04), (20.74±0.15)/(6.42±0.11), (25.09±0.31)/(7.10±0.13), (29.38±0.24)/(8.17±0.09), (33.80±0.16)/(9.02±0.17), (37.89±0.19)/(9.83±0.07) to(16.36±0.06)/(4.85±0.04), (20.54±0.26)/(6.44±0.12), (24.36±0.24)/(7.01±0.33), (28.69±0.25)/(8.07±0.08), (32.97±0.33)/(8.93±0.09), (37.34±0.29)/(9.75±0.08), respectively during the insertion of the suction tube from the suction port of the closed extension tube, and the tidal volume (in L) was decreased from0.361±0.005, 0.592±0.003, 0.631±0.001, 0.642±0.007, 0.633±0.007, 0.626±0.08 to 0.335±0.005, 0.588±0.008, 0.631±0.002, 0.638±0.004, 0.628±0.004, 0.618±0.005.The maximum pressure change of the ventilation circuit was (0.83±0.27) cm H2O and the maximum tidal volume change was (0.008±0.006)L. The changes of airway pressure and tidal volume were significantly lower than those of ventilation circuit connected with open extension tube under the same pressure parameters. Conclusion: The connection of closed extension tube in mechanical ventilation circuit can reduce the airway leakage during artificial airway clearance, which is worthy of clinical recommendation.

[Risk factors associated with prolonged postoperative length of stay of patients with gastric cancer].

Objective: To investigate the risk factors of prolonged postoperative length of stay (LOS) in patients with gastric cancer. Methods: A retrospective study was performed on 2033 patients who underwent curative surgery in Department of Pancreatic-gastric, Cancer Hospital, Chinese Academy of Medical Sciences. Eightieth percentile of postoperative hospital stay for all patients was taken as the cutoff, the patients were divided into the normal group (1 532 patients) and the extended group (501 patients). Logistic regression model was used to determine the risk factors related to prolonged postoperative LOS in gastric cancer. Results: A total of 417 cases with postoperative complications were recruited in extended group. The five highest complications accounting for prolonged LOS were: abdominal infection in 69 cases (13.77%), pleural effusion in 60 cases (11.98%), anastomotic leakage in 43 cases (8.58%), poor wound healing in 34 cases (6.79%), and bleeding in 25 cases (4.99%). Logistic regression analysis showed that age (OR=1.348, P=0.013), surgical procedure (OR=2.712, P<0.001), extent of resection (OR=2.035, P<0.001), degree of incision healing(OR=4.867, P<0.001), and perioperative blood transfusion (OR=1.711, P<0.001) were independent risk factors for prolonged postoperative LOS. Conclusions: The most common complication associated with prolonged postoperative LOS for gastric cancer patients is abdominal infection. Age, surgical procedure, extent of resection, degree of incision healing, and perioperative blood transfusion are the independent risk factors for prolonged postoperative LOS.

[A method for constructing three-dimensional face symmetry reference plane based on weighted shape analysis algorithm].

OBJECTIVE: To establish a novel method based on three-dimensional (3D) shape analysis and weighted Procrustes analysis (WPA) algorithm to construct a 3D facial symmetry reference plane (SRP), automatically assigning weight to facial anatomical landmarks. The WPA algorithm suitability for commonly observed clinical cases of mandibular deviation were analysed and evaluated. METHODS: Thirty patients with mandibular deviation were recruited for this study. The 3D facial SRPs were extracted independently based on original-mirror alignment method. Thirty-two anatomical landmarks were selected from the overall region by three times to obtain the mean coordinate. The SRP of experimental groups 1 and 2 were using the standard Procrustes analysis (PA) algorithm and WPA algorithm, respectively. A reference plane defined by experts based on regional iterative closest point (ICP) algorithm, served as the ground truth. Three experts manually selecting facial regions with good symmetry for original model, and common region was included in the study. The angle error values between the SRP of WPA algorithm in the experimental group 1 and the truth plane were evaluated in this study, and the SRP of PA algorithm of experimental group 2 was calculated in the same way. Statistics and measurement analysis were used to comprehensively evaluate the clinical suitability of the WPA algorithm to calculate the SRP. A paired t-test analysis (two-tailed) was conducted to compare the angles. RESULTS: The average angle error between the SRP of WPA algorithm and the ground truth was 1.53°±0.84°, which was smaller than that between the SRP of PA and the ground truth (2.06°±0.86°). There were significant differences in the angle errors among the groups (P < 0.05). For the patients with severe mandibular deviation that the distance between pogonion and facial midline greater than 12 mm, the average angle error of the WPA algorithm was 0.86° smaller than that of the PA algorithm. CONCLUSION: The WPA algorithm, based on weighted shape analysis, can provide a more adaptable SRP than the standard PA algorithm when applied to mandibular deviation patients and preliminarily simulate the diagnosis strategies of clinical experts.

[Long-term outcome of patients with hypertrophic obstructive cardiomyopathy post percutaneous transluminal septal ablation].

Objective: To evaluate the long-term outcome of patients with hypertrophic obstructive cardiomyopathy(HOCM) after percutaneous transluminal septal ablation(PTSMA). Methods: HOCM patients who underwent PTSMA and surgical myectomy at the Chest Hospital of Shanghai Jiao Tong University from April 2001 to February 2019 were included in this retrospective analysis. Patients were divided into PTSMA group and surgical myectomy group. In addition, patients undergoing PTSMA were further divided into HOCM-PTSMA non-survivor group and HOCM-PTSMA survivor group. The general clinical information, procedural/surgical information and complications during hospitalization were compared between groups. Multivariate Cox regression model was used to analyze the independent risk factors for all-cause death in HOCM patients after PTSMA. Results: A total of 104 patients with HOCM who underwent PTSMA were enrolled. Mean age of the patients was (54±15) years old, including 41 females (38.7%). The follow-up time was 37.5(14.3, 76.8) months. At the last follow-up, 12 patients died (HOCM-PTSMA non-survivor group) and 92 were alive(HOCM-PTSMA survivor group). The proportion of patients with NYHA function class Ⅲ/Ⅳ was higher(P=0.036), and the posterior wall of the left ventricle was thicker(P=0.006) in the HOCM-PTSMA non-survivor group than in the HOCM-PTSMA survivor group. The immediate success rate of PTSMA in this cohort was 66%(70/104). The amount of absolute alcohol during the operation in the HOCM-PTSMA non-survivor group was (2.9±0.8) ml, which tended to be higher as compared to that in the HOCM-PTSMA survivor group((2.4±1.0)ml, P=0.056). Kaplan-Meier survival curve analysis showed that patients with HOCM who underwent PTSMA had an all-cause mortality-free survival rate of 90.1%, 78.3%, and 56.9% at 5, 10 and 15 years, and a HOCM-free survival rate of 91.3%, 79.4% and 57.7% at 5, 10 and 15 years, respectively. Multivariate Cox regression analysis showed that age≥ 65 years was an independent risk factor for all-cause death after PTSMA in patients with HOCM (HR=2.697, 95%CI 1.292-18.977, P=0.020). There were 32 patients in the surgical myectomy group. The proportion of patients with NYHA function class Ⅲ/Ⅳ was higher than that in the PTSMA group(P<0.001), while age, gender, and major comorbidities(atrial fibrillation, coronary heart disease, hypertension, and diabetes) as well as the left atrium dimension were all similar between the two groups(all P>0.05). Patients in the surgical myectomy group were followed up for 38.0(17.6, 64.2)months, and no deaths occurred during the follow-up period. Kaplan-Meier survival curve analysis showed that there were no statistically significant differences in all-cause-free and HOCM-free survival rates between patients in PTSMA group and surgical myectomy group(P=0.089 and 0.110, respectively). Conclusion: PTSMA is safe and effective for the treatment of patients with HOCM, and the long-term survival rate of patients after PTSMA is similar as patients undergoing classical surgical myectomy surgery.

Effect of Bifidobacterium on the mRNA expression levels of TRAF6, GSK-3ß, and microRNA-146a in LPS-stimulated rat intestinal epithelial cells.

We investigated the effect of inactivated Bifidobacterium on the mRNA expression of TRAF6, GSK-3ß, and microRNA-146a in lipopolysaccharide (LPS)-stimulated rat small intestinal epithelial cells (IEC-6s). IEC-6s were randomly divided into an LPS group, a culture supernatant group, and an inactivated bacteria group. After stimulation with LPS for 5 h, the three groups were treated as follows: the LPS group was cultured for 24 h with sterile saline; the culture supernatant group was cultured with Bifidobacterium (infantis strain) culture supernatant for 24 h; and the inactivated bacteria group was cultured with inactivated infantis Bifidobacterium for 24 h. Reverse transcription polymerase chain reaction was used to determine mRNA expression levels. The mRNA expression levels of TRAF-6 and GSK-3ß in the culture supernatant group were lower, and microRNA-146a expression was higher, compared with the LPS group (t = 5.278, P = 0.000; t = 6.316, P = 0.000; t = 13.218, P = 0.000, respectively). GSK-3ß mRNA expression in the inactivated bacteria group was lower than in the LPS group (t = 4.837, P = 0.000). There was no difference in the mRNA expression levels of TRAF-6 and microRNA-146a between the two groups (t = 0.732, P = 0.472 and t = 1.463, P = 0.164). Both the culture supernatant and the inactivated Bifidobacterium had a protective effect on LPS-stimulated IEC-6s. The protective effect of Bifidobacterium may be achieved through increased microRNA-146a by reducing levels of TRAF6 and GSK-3ß; the protective effect of inactivated Bifidobacterium may be achieved by reducing levels of GSK-3ß.

[Mitigating metal artifacts from cobalt-chromium alloy crowns in cone-beam CT images through deep learning techniques].

Objective: To develop and evaluate metal artifact removal systems (MARS) based on deep learning to assess their effectiveness in removing artifacts caused by different thicknesses of metals in cone-beam CT (CBCT) images. Methods: A full-mouth standard model (60 mm×75 mm×110 mm) was three-dimensional (3D) printed using photosensitive resin. The model included a removable and replaceable target tooth position where cobalt-chromium alloy crowns with varying thicknesses were inserted to generate matched CBCT images. The artifacts resulting from cobalt-chromium alloys with different thicknesses were evaluated using the structural similarity index measure (SSIM) and peak signal-to-noise ratio (PSNR). CNN-MARS and U-net-MARS were developed using a convolutional neural network and U-net architecture, respectively. The effectiveness of both MARSs were assessed through visualization and by measuring SSIM and PSNR values. The SSIM and PSNR values were statistically analyzed using one-way analysis of variance (α=0.05). Results: Significant differences were observed in the range of artifacts produced by different thicknesses of cobalt-chromium alloys (all P<0.05), with 1 mm resulting in the least artifacts. The SSIM values for specimens with thicknesses of 1.0, 1.5, and 2.0 mm were 0.916±0.019, 0.873±0.010, and 0.833±0.010, respectively (F=447.89, P<0.001). The corresponding PSNR values were 20.834±1.176, 17.002±0.427, and 14.673±0.429, respectively (F=796.51, P<0.001). After applying CNN-MARS and U-net-MARS to artifact removal, the SSIM and PSNR values significantly increased for images with the same thickness of metal (both P<0.05). When using the CNN-MARS for artifact removal, the SSIM values for 1.0, 1.5 and 2.0 mm were 0.938±0.023, 0.930±0.029, and 0.928±0.020 (F=2.22, P=0.112), while the PSNR values were 30.938±1.495, 30.578±2.154 and 30.553±2.355 (F=0.54, P=0.585). When using the U-net-MARS for artifact removal, the SSIM values for 1.0, 1.5 and 2.0 mm were 0.930±0.024, 0.932±0.017 and 0.930±0.012 (F=0.24, P=0.788), and the PSNR values were 30.291±0.934, 30.351±1.002 and 30.271±1.143 (F=0.07, P=0.929). No significant differences were found in SSIM and PSNR values after artifact removal using CNN-MARS and U-net-MARS for different thicknesses of cobalt-chromium alloys (all P>0.05). Visualization demonstrated a high degree of similarity between the images before and after artifact removal using both MARS. However, CNN-MARS displayed clearer metal edges and preserved more tissue details when compared with U-net-MARS. Conclusions: Both the CNN-MARS and U-net-MARS models developed in this study effectively remove the metal artifacts and enhance the image quality. CNN-MARS exhibited an advantage in restoring tissue structure information around the artifacts compared to U-net-MARS.

[Mitigating metal artifacts in cone-beam CT images through deep learning techniques].

Objective: To develop and evaluate metal artifact removal systems (MARSs) based on deep learning to assess their effectiveness in removing artifacts caused by different thicknesses of metals in cone-beam CT (CBCT) images. Methods: A full-mouth standard model (60 mm×75 mm×110 mm) was three-dimensional (3D) printed using photosensitive resin. The model included a removable and replaceable target tooth position where cobalt-chromium alloy crowns with varying thicknesses were inserted to generate matched CBCT images. The artifacts resulting from cobalt-chromium alloys with different thicknesses were evaluated using the structural similarity index measure (SSIM) and peak signal-to-noise ratio (PSNR). CNN-MARS and U-net-MARS were developed using a convolutional neural network and U-net architecture, respectively. The effectiveness of both MARSs were assessed through visualization and by measuring SSIM and PSNR values. The SSIM and PSNR values were statistically analyzed using one-way analysis of variance (α=0.05). Results: Significant differences were observed in the range of artifacts produced by different thicknesses of cobalt-chromium alloys (all P<0.05), with 1 mm resulting in the least artifacts. The SSIM values for specimens with thicknesses of 1.0 mm, 1.5 mm, and 2.0 mm were 0.916±0.019, 0.873±0.010, and 0.833±0.010, respectively (F=447.89, P<0.001). The corresponding PSNR values were 20.834±1.176, 17.002±0.427, and 14.673±0.429, respectively (F=796.51, P<0.001). After applying CNN-MARS and U-net-MARS to artifact removal, the SSIM and PSNR values significantly increased for images with the same thickness of metal (both P<0.05). When using the CNN-MARS for artifact removal, the SSIM values for 1.0, 1.5 and 2.0 mm were 0.938±0.023, 0.930±0.029, and 0.928±0.020 (F=2.22, P=0.112), while the PSNR values were 30.938±1.495, 30.578±2.154 and 30.553±2.355 (F=0.54, P=0.585). When using the U-net-MARS for artifact removal, the SSIM values for 1.0, 1.5 and 2.0 mm were 0.930±0.024, 0.932±0.017 and 0.930±0.012 (F=0.24, P=0.788), and the PSNR values were 30.291±0.934, 30.351±1.002 and 30.271±1.143 (F=0.07, P=0.929). No significant differences were found in SSIM and PSNR values after artifact removal using CNN-MARS and U-net-MARS for different thicknesses of cobalt-chromium alloys (all P>0.05). Visualization demonstrated a high degree of similarity between the images before and after artifact removal using both MARSs. However, CNN-MARS displayed clearer metal edges and preserved more tissue details when compared with U-net-MARS. Conclusions: Both the CNN-MARS and U-net-MARS models developed in this study effectively remove the metal artifacts and enhance the image quality. CNN-MARS exhibited an advantage in restoring tissue structure information around the artifacts compared to U-net-MARS.

[Preliminary study on the method of automatically determining facial landmarks based on three-dimensional face template].

Objective: To explore the establishment of an efficient and automatic method to determine anatomical landmarks in three-dimensional (3D) facial data, and to evaluate the effectiveness of this method in determining landmarks. Methods: A total of 30 male patients with tooth defect or dentition defect (with good facial symmetry) who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from June to August 2021 were selected, and these participants' age was between 18-45 years. 3D facial data of patients was collected and the size normalization and overlap alignment were performed based on the Procrustes analysis algorithm. A 3D face average model was built in Geomagic Studio 2013 software, and a 3D face template was built through parametric processing. MeshLab 2020 software was used to determine the serial number information of 32 facial anatomical landmarks (10 midline landmarks and 22 bilateral landmarks). Five male patients with no mandibular deviation and 5 with mild mandibular deviation were selected from the Department of Orthodontics or Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from June to August 2021. 3D facial data of patients was collected as test data. Based on the 3D face template and the serial number information of the facial anatomical landmarks, the coordinates of 32 facial anatomical landmarks on the test data were automatically determined with the help of the MeshMonk non-rigid registration algorithm program, as the data for the template method to determine the landmarks. The positions of 32 facial anatomical landmarks on the test data were manually determined by the same attending physician, and the coordinates of the landmarks were recorded as the data for determining landmarks by the expert method. Calculated the distance value of the coordinates of facial anatomical landmarks between the template method and the expert method, as the landmark localization error, and evaluated the effect of the template method in determining the landmarks. Results: For 5 patients with no mandibular deviation, the landmark localization error of all facial anatomical landmarks by template method was (1.65±1.19) mm, the landmark localization error of the midline facial anatomical landmarks was (1.19±0.45) mm, the landmark localization error of bilateral facial anatomical landmarks was (1.85±1.33) mm. For 5 patients with mild mandibular deviation, the landmark localization error of all facial anatomical landmarks by template method was (2.55±2.22) mm, the landmark localization error of the midline facial anatomical landmarks was (1.85±1.13) mm, the landmark localization error of bilateral facial anatomical landmarks was (2.87±2.45) mm. Conclusions: The automatic determination method of facial anatomical landmarks proposed in this study has certain feasibility, and the determination effect of midline facial anatomical landmarks is better than that of bilateral facial anatomical landmarks. The effect of determining facial anatomical landmarks in patients without mandibular deviation is better than that in patients with mild mandibular deviation.

Diagnostic value of CT perfusion imaging for parotid neoplasms.

OBJECTIVES: To assess the value of CT perfusion imaging in the differentiation of different histological categorization of benign tumours from malignant tumours in patients with parotid neoplasms. METHODS: CT perfusion was successfully performed in 62 patients with parotid neoplasms whose diagnoses were confirmed by surgery or biopsy. The software generated a tissue time-density curve (TDC) and measured blood volume, blood flow, mean transit time and capillary permeability surface product. One-way ANOVA and receiver operating characteristic curves were used to analyse the difference and diagnostic efficacies of all perfusion data between each one of the benign tumours and malignancies. Statistical significance was assigned at the 5% level. RESULTS: Pleomorphic adenomas mainly had a gradually ascending TDC. Warthin tumours showed a fast ascent followed by a fast descent. The TDC of basal cell adenomas had a fast ascension followed by a plateau, then a gradual descent. Malignant tumours mainly showed a rapidly ascending curve with a stable plateau. Significant differences were observed in blood flow, blood volume and mean transit time between pleomorphic adenomas and malignant tumours (p < 0.05) as well as in blood flow and blood volume between the Warthin tumours, the basal cell adenomas and the malignant tumours (p < 0.05). Differences in permeability surface between the basal cell adenomas and malignant tumours were significant (p < 0.01). CONCLUSION: CT perfusion of parotid gland could provide TDC and perfusion data, which were useful in the differentiation of different histological benign tumours and malignant tumours in the parotid gland.

RGD-conjugated iron oxide magnetic nanoparticles for magnetic resonance imaging contrast enhancement and hyperthermia.

The purpose of this study was to develop a specific targeting magnetic nanoparticle probe for magnetic resonance imaging and therapy in the form of local hyperthermia. Carboxymethyl dextran-coated ultrasmall superparamagnetic iron oxide nanoparticles with carboxyl groups were coupled to cyclic arginine-glycine-aspartic peptides for integrin α(v)ß3 targeting. The particle size, magnetic properties, heating effect, and stability of the arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide were measured. The arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide demonstrates excellent stability and fast magneto-temperature response. Magnetic resonance imaging signal intensity of Bcap37 cells incubated with arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide was significantly decreased compared with that incubated with plain ultrasmall superparamagnetic iron oxide. The preferential uptake of arginine-glycine-aspartic-ultrasmall superparamagnetic iron oxide by target cells was further confirmed by Prussian blue staining and confocal laser scanning microscopy.