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Early recurrence results in poor prognosis of patients with hepatocellular carcinoma (HCC) after liver transplantation (LT). This study aimed to explore the value of computed tomography (CT)-based radiomics nomogram in predicting early recurrence of patients with HCC after LT.A cohort of 151 patients with HCC who underwent LT between December 2013 and July 2019 were retrospectively enrolled. A total of 1218 features were extracted from enhanced CT images. The least absolute shrinkage and selection operator algorithm (LASSO) logistic regression was used for dimension reduction and radiomics signature building. The clinical model was constructed after the analysis of clinical factors, and the nomogram was constructed by introducing the radiomics signature into the clinical model. The predictive performance and clinical usefulness of the three models were evaluated using receiver operating characteristic (ROC) curve analysis and decision curve analysis (DCA), respectively. Calibration curves were plotted to assess the calibration of the nomogram.There were significant differences in radiomics signature among early recurrence patients and non-early recurrence patients in the training cohort (P0.001) and validation cohort (P0.001). The nomogram showed the best predictive performance, with the largest area under the ROC curve in the training (0.882) and validation (0.917) cohorts. Hosmer-Lemeshow testing confirmed that the nomogram showed good calibration in the training (P = 0.138) and validation (P = 0.396) cohorts. DCA showed if the threshold probability is within 0.06-1, the nomogram had better clinical usefulness than the clinical model.Our CT-based radiomics nomogram can preoperatively predict the risk of early recurrence in patients with HCC after LT.

To assess the prevalence, location, diameter, course and anastomosis of the lateral lingual foramina (LLF) and canals (LLCs) in a northern Chinese population using CBCT.CBCT images of 506 patients (181 male and 325 female, mean age 21.03 ± 8.11 years) were collected. The prevalence, location, diameter, length, angle and anastomosis of the LLF and LLCs were assessed. The measurement variables were analysed by sex and age. Statistical analysis was performed using SPSS (v. 25, IBM, Armonk, NY, USA).A total of 461 LLF were detected in 307 (60.7%) subjects, 175 (57.0%) of whom had unilateral LLF and 132 (43.0%) of whom had bilateral LLF, with each lateral having one to four LLF. The majority of LLF (375/461, 81.3%) were located below the premolars, particularly the first premolar. The mean diameter of the LLF was 0.58 ± 0.20 mm. The mean vertical distance from the LLF to the inferior border and the alveolar crest was 6.68 ± 1.43 mm and 23.65 ± 2.89 mm, respectively. In total, 197 LLCs were visible in the cancellous bone and evaluated. The mean length of LLCs was 6.26 ± 1.29 mm, and the mean angle of LLCs was 140.64° ± 17.29°. The overwhelming majority (93.4%) of LLCs communicated with the mandibular incisive canal and the rest connected with the mandibular canal.The prevalence of LLCs was high in the northern Chinese population. The presence of LLCs is a significant predictor of communication with the mandibular incisive canal.

The objective of our study was to develop and validate a deep learning approach based on convolutional neural networks (CNNs) for automatic detection of the mandibular third molar (M3) and the mandibular canal (MC) and evaluation of the relationship between them on CBCT. A dataset of 254 CBCT scans with annotations by radiologists was used for the training, the validation, and the test. The proposed approach consisted of two modules: (1) detection and pixel-wise segmentation of M3 and MC based on U-Nets; (2) M3-MC relation classification based on ResNet-34. The performances were evaluated with the test set. The classification performance of our approach was compared with two residents in oral and maxillofacial radiology. For segmentation performance, the M3 had a mean Dice similarity coefficient (mDSC) of 0.9730 and a mean intersection over union (mIoU) of 0.9606; the MC had a mDSC of 0.9248 and a mIoU of 0.9003. The classification models achieved a mean sensitivity of 90.2%, a mean specificity of 95.0%, and a mean accuracy of 93.3%, which was on par with the residents. Our approach based on CNNs demonstrated an encouraging performance for the automatic detection and evaluation of the M3 and MC on CBCT. Clinical relevance An automated approach based on CNNs for detection and evaluation of M3 and MC on CBCT has been established, which can be utilized to improve diagnostic efficiency and facilitate the precision diagnosis and treatment of M3.

To investigate the bilateral symmetry of double root canals, variation in root canal bifurcation and position of canal orifices in mandibular incisors in a Chinese population.A total of 149 subjects with mandibular incisors with two canals were selected from 866 patients based on CBCT images and divided into three groups: group 1 (21 years), group 2 (21-40 years) and group 3 (40 years). The prevalence of bilateral symmetry of double root canals (type III and type V), the distance between the cementoenamel junction (CEJ) and the bifurcation (D1) and the distance between the two canal orifices (D2) were calculated and analysed.The bilateral symmetry of type III for mandibular central incisors (MCIs) (44.4%) was significantly lower than that for mandibular lateral incisors (MLIs) (63.4%). D1 was greater in group 1 (4.63 ± 1.35mm) than in group 2 (3.99 ± 1.02 mm) and group 3 (3.90 ± 1.95 mm). D2 was shorter in in MCIs (0.65 ± 0.20 mm) than in MLIs (0.74 ± 0.22 mm).Special attention is required in the root canal treatment of mandibular incisors, especially in patients aged above 21 years.

This study evaluated the occurrence of degenerative temporomandibular joint (TMJ) changes in adolescents and young adults with recent on-set disc displacement without reduction (DDw/oR) using high-resolution cone beam computed tomography (CBCT). The associations between types of osteoarthrosis (OA) changes and clinical factors including disease duration were also examined. CBCT and clinical data of 300 patients (84.70% females, mean age 20.93 ± 4.77 years) diagnosed with unilateral DDw/oR (≤12 months) based on RDC/TMD were acquired. CBCT images of both symptomatic and contralateral asymptomatic TMJs were independently evaluated and scored by two radiologists. Associations between OA changes and gender, age, mouth opening and duration of DDw/oR were analyzed statistically. Condylar OA changes were present in 59.30% of the joints with DDw/oR. Early-stage OA changes (loss of continuity of articular cortex and/or surface destruction) constituted most (45.67%) of the alterations. Prevalence of early-stage OA increased from 24% to about 60% one month after TMJ closed-lock occurred. Logistic regression analysis showed the risk of developing early-stage OA changes was 5.33 times higher one month after onset of DDw/oR. A high prevalence of degenerative TMJ changes was observed with recent on-set DDw/oR in adolescents and young adults. Early diagnosis and intervention of DDw/oR is therefore prudent.

BACKGROUND Motivated by the interest around blockchains, we examine whether the healthcare sector benefits from this emerging technology, taking the case of China. Since blockchain technology can possibly provide a high level of privacy protection and robust and strong cybersecurity solution, this technology offers a promising new distributed framework across a range of uses and stakeholders. Despite of the shift towards Bitcoin, attitudes of China governments towards blockchains and its application on healthcare evaluate forward through setting policies for data governance. OBJECTIVE To evaluate blockchain's roles in strengthening cybersecurity and protecting privacy in healthcare, we summarized the evidence on the initiative evolution, institutions and policy issues from the macroscopic and microcosmic views. METHODS From the perspective of data governance, this paper investigated how blockchain can make it possible to benefit healthcare from the security and privacy considerations. This paper also discussed and evaluated China’ initiative evolution, institutions, and policy issues on this front. This paper also compared the development of blockchains in healthcare in China and those in the other world. Then, a case study was conducted on the implication of smart contract in healthcare data governance. RESULTS Through analysis from the macroscopic, the regulators mainly including the national governments focused more on promoting the innovation of the emerging technology and standardization of its applications and service, while preventing the risk of block chain and related virtual currency. Meanwhile, block chain and related technologies had been initiative in the industries to develop for auditing, protecting privacy and data sharing in pharmaceutical supply chains and electronic medical records. Besides, smart contract as one pillar of blockchain technologies had been integrated in the patient's medical records, attributing to the innovation of chronic disease management service. CONCLUSIONS The results also supported the argument that China's initiative evolution, institutions, and policy issues on blockchain in healthcare attribute to increasing the data privacy, interoperability and scalability. The regulators made public policy efforts on protecting privacy using blockchain, assisting key stakeholders in healthcare blockchain implementation and increasing investment in this technology. To enrich the blockchain ecosystem, the regulators of blcokchain should provide legal clarity and more information for public–private partnerships to engage in smart contracts.

Objective The aim of this study was to compare root surface area (RSA) measurements of single-root teeth in a sheep mandible based on cone beam computed tomography (CBCT) with measurements made with an optical scanner. Study Design Eight anterior teeth of a sheep cadaver mandible were scanned in situ by using CBCT with 3 different exposure parameters, followed by treatment with smoothing software. The teeth were then extracted and scanned individually with an optical scanner. Three-dimensional digital models of the teeth were reconstructed on the basis of CBCT and optical scanner data. RSA data were calculated, and an equivalence test was used to statistically compare the measurements with significance of difference established at α = 0.05. Results The means of the differences between RSA measurements from CBCT and optical scanning ranged from 0.33% to 3.01%. There were no statistically significant differences between the 2 methods. The smoothing parameters for good fitness of the linear regression were determined to be 0.8 for the smooth factor, 8 for iterations, and 0 for compensate shrinkage. Conclusions The proposed CBCT technique to measure RSA is feasible. RSA data obtained from CBCT in situ are as accurate as optical scanner measurements ex vivo.

This study aimed to investigate the characteristic features of CT images of diffuse tenosynovial giant cell tumor (D-TSGCT) from the temporomandibular joint (TMJ) to understand CT imaging diagnosis of the disease.CT images and clinical information from 10 patients with D-TSGCT of TMJ were recruited for retrospective analysis from March 2013 to March 2017 in Peking University Hospital of Stomatology. All cases were treated by surgery and confirmed by pathology.CT scan demonstrated hyperdense soft-tissue masses and various kinds of calcification in all of the 10 subjects. Contrast-enhanced scan exhibited obvious enhancement in six patients. Bone destruction of the mandibular condyles and skull base was found in seven and six subjects, respectively.CT appearance of D-TSGCT of the TMJ is characterized by hyperdense soft tissue with calcification, further enhancement in contrast-enhanced scan, and bone destruction in the mandibular condyles and skull base in some cases.目的 探讨颞下颌关节弥漫型腱鞘巨细胞瘤CT影像的特征性表现，提高对该疾病的认识及影像诊断能力。方法 回顾性分析北京大学口腔医院2013年3月—2017年3月收治的10例经手术及病理诊断为颞下颌关节弥漫型腱鞘巨细胞瘤患者的CT表现及临床资料。结果 10例患者均表现为高密度软组织肿块伴不同程度钙化，6例患者的增强扫描影像均表现为显著强化，7例患者出现髁突骨质吸收或破坏，6例患者伴有颅底骨质破坏。结论 颞下颌关节弥漫型腱鞘巨细胞瘤的CT特征表现为高密度软组织肿块伴钙化和显著强化，可伴有髁突和颅底骨质的吸收或破坏。.

Anterior repositioning splints (ARS) are used primarily for the management of temporomandibular joint (TMJ) anterior disc displacement with reduction (ADDwR). However, the exact physiological effects of ARS are still unclear. This study investigated the short and long-term effects of ARS on disc and condyle angles/positions by metric analysis. Twenty-two subjects diagnosed with ADDwR were recruited. Maxillary full-coverage ARS were fabricated, and MRI of TMJs was obtained before splint treatment, immediate post-insertion and 6 months after splint treatment. Disc-condyle relationship was determined by disc-condyle angle measurement. Disc and condyle positions were described as X-Y coordinates with the summit of glenoid fossa as the origin of the coordinates. Thirty-two TMJs were classified as ADDwR and 12 were normal. Upon ARS insertion, all TMJs with ADDwR got normal disc-condyle relationships. The condyles moved significantly forward and downward, while the discs moved significantly backward and upward. MRI at 6 months after treatment (without ARS insertion) indicated that only 40·6% (13/32) of the joints were maintained in the normal disc-condyle relationship. The majority of condyles returned to their pre-treatment positions, while the discs generally moved anteriorly again. The use of ARS resulted in forward and downward condyle movement, and a concurrent backward movement of the disc resulting in ideal spatial disc-condyle relationship. The stability of this relationship, however, could not be maintained in the majority of TMJs upon ARS removal. Findings explain the good short-term clinical outcomes with ARS and their relatively lower efficacy in the long term.

Rural medical and health collaborative working platform is a collaborative platform which combines information processing system, office management, and telemedicine and computer aided diagnosis system. The personal health records, expert information, fund management information, and any others on the rural medical and health collaborative working platform are user's privacy data, which need strong security protection. In order to achieve efficient data sharing between doctors and patients and ensure the data security, there must be strict access control policy to be applied on the rural medical and health collaborative working platform. In this paper, the access control and its application on the rural medical and health collaborative working platform are discussed from the perspective of user role management.

Objective The aim of this study was to evaluate osseous changes accompanying anterior repositioning splint (ARS) therapy in patients with temporomandibular joint disk displacement. Study Design Cone-beam computerized tomography (CBCT) data of 36 patients with intermittent or permanent closed-lock were used; 23 patients with permanent closed-lock had their displaced disks physically reduced by mandibular manipulation before ARS therapy. CBCT was performed before and ∼6 months after ARS therapy. The presence and location of “double contour” images suggesting condylar bone remodeling were statistically analyzed. Results The “double contour” images after ARS therapy were observed in ∼80% of patients, more frequently in joints with signs of displaced disks. The “double contour” appeared more often on the posterior bevel as well as the medial and middle part of condyles (P Conclusions ARS therapy can facilitate regenerative remodeling of condyles. CBCT is a useful tool for monitoring osseous changes in condyles.

Background Skeletal unloading during spaceflight results in bone loss. This study investigated whether laser acupuncture could be an effective countermeasure to prevent unloading-induced bone loss in rats. Methods There were 18 rats that were randomly assigned into three groups: a control group, a tail-suspended group (TS), and a tail-suspended with laser acupuncture treatment group (TSA). The rats in the TSA group were treated with laser acupuncture at the KI1 (Yong Quan) and ST36 (Zu San Li) acupoints of the left leg for 3 min per day. Bone mineral density (BMD), biomechanical properties, and histomorphometry of both tibiae were determined after the animals were euthanized at the end of week 4. Results Compared with the control group, BMD in the TS group significantly decreased by 12.3% in cortical bone and 15.1% in cancellous bone, whereas BMD in the TSA group decreased by only 3.1% in cortical bone and 9.0% in cancellous bone. The hardness of cortical bone dropped 44.1% in the TS group and 22.3% in the TSA group compared with the control group. The histomorphometry data were in accordance with BMD measurements. Although acupuncture treatment was applied only to the left side, we observed similar changes between the measurements of both the left and right tibiae. Conclusion Laser acupuncture on KI1 and ST36 can inhibit bone loss in rats subjected to unloading. The fact that similar changes between the right and left sides when only the left limbs were treated suggests that the preventive effect of laser acupuncture occurs via a systemic regulation.

To investigate the root canal configuration of mandibular anterior teeth with cone-beam computed tomography (CBCT).The CBCT imaging data of 866 patients who visited Peking University School of Stomatology from October 2012 to July 2013 were inspected by an endodontist anda radiologists together. A total of 4 674 mandibular anterior teeth were involved. The number of root, root canals and root canal configuration were observed and analyzed statistically (Chi-squared test).All the mandibular central incisors and lateral incisors were single root, and 0.7% (11/1 542) of canines were double roots. 6.7% (105/1 566) of central incisors, 17.4% (273/1 566) of lateral incisors and 3.0% (46/1 542) of canines had double root canals. The frequency of symmetry of double root canal was 58.7% (37/63) in central incisors, 76.1% (108/142) in lateral incisors and 29.6% (8/27) in canines. The highest frequency of double root canals in different ages was 9.8% (28/287, 31-40 years) in central incisors, 21.5% (61/284, 31-40 years) in lateral incisors and 9.2% (19/207, ≥51 years) in canines. Vertucci type III canal configurations were the most prevalent in mandibular anterior teeth.The double root canals are most common in mandibular lateral incisors. The highest incidence of symmetry of double root canal is also observed in mandibular lateral incisors. Vertucci type III canal configurations are the most frequent type in mandibular anterior teeth.

Little is known about avascular necrosis of the mandibular condyle, which is necrosis of the epiphyseal or subarticular bone secondary to a diminished or disrupted blood supply in the absence of infection. We present a case of a large subarticular cystlike lesion that was found using cone-beam computed tomography (CBCT). There was an absence of osteoarthrosis, and the condylar articular surface was relatively intact. The patient's history, physical examination, and magnetic resonance images supported the diagnosis of avascular necrosis of the mandibular condyle. After 4 months of conservative therapy, new bone was observed in the cystlike marrow lesion, and a smooth articular surface was reestablished. Subarticular cystlike lesions without the collapse of the articular surface of mandibular condyles may be an early indicator of avascular necrosis.

We investigated subchondral formation of cortical bone in the condyles of adolescents and young adults, and looked for age-related and sex-related differences in bony formation with the aid of cone-beam computed tomography data in 1438 subjects aged between 10 and 30 years. The scans were part of the hospital's clinical protocol for patients seeking orthodontic or orthognathic treatment. No patient had signs or symptoms of temporomandibular disorders. Central images of the coronal and sagittal planes of the condyle were acquired and scored. Subchondral formation of cortical bone was seen as a high-density compact linear image, and subjects were classified into complete, partial, and no formation. Subchondral formation of cortical bone was first seen at the ages of 13-14 in boys and 12-13 in girls. Complete cortical bony formation was seen after the age of 22 years for men and 21 for women. We conclude that cortical bone begins to form around the periphery of the condyles during adolescence (12-14 years). A continuous, homogeneous, and compact cortical bony layer is established in young adults by the age of 21-22, indicating full development of the mandibular condyle. The condylar bone developed gradually and was generally fully developed a year earlier in women than men.

The present article discusses the clustering analysis used in the near-infrared (NIR) spectroscopy analysis of Chinese traditional medicines, which provides a new method for the classification of Chinese traditional medicines. Samples selected purposely in the authors' research to measure their absorption spectra in seconds by a multi-channel NIR spectrometer developed in the authors' lab were safrole, eucalypt oil, laurel oil, turpentine, clove oil and three samples of costmary oil from different suppliers. The spectra in the range of 0.70-1.7 microm were measured with air as background and the results indicated that they are quite distinct. Qualitative mathematical model was set up and cluster analysis based on the spectra was carried out through different clustering methods for optimization, and came out the cluster correlation coefficient of 0.9742 in the authors' research. This indicated that cluster analysis of the group of samples is practicable. Also it is reasonable to get the result that the calculated classification of 8 samples was quite accorded with their characteristics, especially the three samples of costmary oil were in the closest classification of the clustering analysis.

Nonunion remains a major complication after skeletal trauma. In the last decade, extracorporeal shock wave therapy has become a common tool for the treatment of delayed unions or non-unions. With the help of a review of the literature, the current author gave an overview of indications, choices of devices, success rates and complications for ESWT in the treatment of non-unions. The conceivable mechanism was also outlined.