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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.

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.

Objective: To evaluate the effect of bite positions characterizing different splint treatments (anterior repositioning and stabilization splints) on the disc-condyle relation in patients with TMJ disc displacement with reduction (DDwR), using magnetic resonance imaging (MRI). Material and Methods: 37 patients, with a mean age of 18.8±4.3 years (7 male and 30 females) and diagnosed with DDwR based on the RDC/TMD, were recruited. MRI metrical analysis of the spatial changes of the disc/condyle, as well as their relationships, was done in three positions: maximum intercuspation (Position 1), anterior repositioning splint position (Position 2), and stabilization splint position (Position 3). Disc/condyle coordinate measurements and disc condyle angles were determined and compared. Results: In Position 1, the average disc-condyle angle was 53.4° in the 60 joints with DDwR, while it was −13.3° with Position 2 and 30.1° with Position 3. The frequency of successful "disc recapture" with Position 2 was significantly higher (58/60, 96.7%) than Position 3 (20/60, 33.3%). In Positions 2 and 3, the condyle moved forward and downward while the disc moved backward. The movements were, however, more remarkable with Position 2. Conclusions: Anterior repositioning of the mandible improves the spatial relationship between the disc and condyle in patients with DDwR. In addition to anterior and inferior movement of the condyle, transitory posterior movement of the disc also occurred.

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.

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.

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.

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.

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.