Objective:To evaluate the efficacy and safety of intrasaccular flow disruptor in wide-necked intracranial aneurysms.Methods:One hundred and seventeen patients with wide-necked intracranial aneurysms treated with intrasaccular flow disruptor were collected from Department of Neurointervention (First Affiliated Hospital of Zhengzhou University), Department of Neurosurgery (Beijing Tiantan Hospital, Capital Medical University), Department of Cerebrovascular Surgery, Neurosurgery Center (Zhujiang Hospital, Southern Medical University), and Department of Neurosurgery (First Affiliated Hospital of Harbin Medical University) from August 2022 to March 2024. Raymond-Roy Occlusion Classification (RROC) was employed to evaluate aneurysm embolization immediately after procedure; cranial CT or MRI within 48 hours of embolization were performed to identify any new intracranial hemorrhage, subarachnoid hemorrhage, or new symptomatic cerebral infarction related to the intracranial aneurysms. Modified Rankin Scale (mRS) was used to assess the neurological function at discharge. Imaging follow-up and outpatient follow-up were performed at 6 months after embolization to evaluate the aneurysm occlusion degree and complications.Results:A total of 117 intrasaccular flow disruptors were implanted in 117 patients, with a technical success rate of 100%; 115 patients (98.3%) enjoyed successful one-time release of their disruptors, and 2 patients (1.7%) required retrieval and redirection of the disruptors before second successful attempt. Flow disruptor plus stent was performed in 13 patients (11.1%). Immediately after procedure, RROC grading I was noted in 3 patients, grading II in 51 patients and grading III in 63 patients. Cranial CT or MRI within 48 hours of embolization indicated no new intracranial hemorrhage, subarachnoid hemorrhage, or symptomatic cerebral infarction related to the intracranial aneurysms. All patients had mRS score of 0 at discharge. Eighty-three patients completed a 6-month follow-up (RROC grading I in 41 patients, grading II in 33 patients and grading III in 9 patients), without ischemic or hemorrhagic adverse events.Conclusion:The results of this study preliminarily suggest that intrasaccular flow disruptor is effective and safe in wide-necked intracranial aneurysms.

Objective:To evaluate the efficacy and safety of Neuroform Atlas stent-assisted coil embolization in patients with middle cerebral artery bifurcation aneurysms.Methods:A retrospective analysis was performed; the clinical data of 46 patients with middle cerebral artery bifurcation aneurysms accepted Neuroform Atlas stent-assisted coil embolization in First Affiliated Hospital of Zhengzhou University, Beijing Tiantan Hospital Affiliated to Capital Medical University, First Affiliated Hospital of Harbin Medical University, Zhujiang Hospital of Southern Medical University and First Affiliated Hospital of Chongqing Medical University from January 2022 to March 2024 were collected. There were 28 ruptured aneurysms (60.87%) and 18 unruptured aneurysms (39.13%). Follow-up was performed for more than 3 months; Raymond-Roy grading was used to evaluate the aneurysm embolization immediately after embolization and during follow-up; perioperative hemorrhagic or ischemic complications were recorded; modified Rankin Scale (mRS) was used to evaluate the prognosis of the patients at discharge and during follow-up (mRS score≤2: good prognosis, and mRS score>2: poor prognosis).Results:Coil embolization was successful in all 46 patients. DSA immediately after embolization showed that 41 patients (89.13%) had completely occluded aneurysms (Raymond-Roy grading I), 2 patients (4.35%) had residual aneurysm neck (Raymond-Roy grading Ⅱ) and 3 patients (6.52%) had partially occluded aneurysms (Raymond-Roy grading Ⅲ). Perioperative complications occurred in 5 patients, including 2 with postoperative cerebral infarction, 1 with hydrocephalus, 1 with postoperative pneumonia leading to respiratory failure, and 1 with stent thrombosis during embolization. Both at discharge and 3 months after embolization, 43 patients (93.48%) had good prognosis and 3 patients (6.52%) had poor prognosis. No obvious ischemic complications (such as stent restenosis) or hemorrhagic complications (such as re-rupture of the aneurysms) were found in all patients. Thirty patients (65.22%) had imaging follow-up for 6-12 months: 26 (86.67%) had Raymond-Roy grading I, 3 (10.00%) had Raymond-Roy grading II, and 1 (3.33%) had Raymond-Roy grading III.Conclusion:Neuroform Atlas stent-assisted coil embolization has good short-term efficacy and high safety in middle cerebral artery bifurcation aneurysms, but long-term follow-up observation is still needed to verify its efficacy.

Objective:To investigate the effects of 10° head up tilt bed rest (HUT) on human cardiac function via 3D speckle tracking echocardiography (3D-STE), and to study the difference in cardiac function under the submaximal exercise load between the horizontal position and 10° HUBR.Methods:Thirty young healthy volunteers were recruited as the subjects, who were randomly divided into an 10° HUT exercise group and horizontal exercise group with 15 subjects in each. Subjects in both groups were asked to ride the bicycle ergometer in the 10° HUBR position and supine position respectively. The load started with 50 W and was increased by 25 W every 3 min until it reached the maximum of 125 W. Before the exercise (resting state), 1 min after the load was increased each time, and 3 min after exercise (recovery period), the following indices were collected: ①basic cardiac function indices: heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), ②conventional cardiac ultrasound indices: left ventricular ejection fraction (LVEF), stroke volume (SV) and cardiac output (CO), ③left ventricular strain indices: global longitudinal strain (GLS), global circumferential strain (GCS), and global area strain (GAS) measured by 3D-SET. The changes of these indices in the 2 groups of subjects under different exercise loads were observed.Results:The differences in the major effect of the basic heart indices (HR, SBP and DBP), conventional cardiac ultrasound indices (LVEF, SV and CO) and left ventricular strain indices (GLS, GCS and GAS) in response to the exercise load were statistically significant ( F=194.90, 113.66, 17.19, P=0.017, 0.018, 0.001). With the increase of the exercise load, the basic heart indices and conventional cardiac ultrasound indices kept rising, the left ventricular strain indices reached the minimum under a moderate exercise load (75 W), HR, SBP and CO were higher than those of the resting state ( P<0.05 or 0.01). Both LVEF under exercise loads of 75, 100, 125 W and during recovery, and SV under exercise loads of 100, 125 W and during recovery were significantly higher than those of the resting state ( P<0.05 or 0.01), while GLS and GCS under exercise loads of 50, 75, 125 W ( P<0.05 or 0.01), and GAS under exercise loads of 50, 75 W ( P<0.01) were significantly lower. There were statistically significant differences not only in GCS across the groups ( F=4.60, P=0.026) but also in DBP due to the interactions between the grouping and exercise loads ( F=3.13, P=0.031). DBP was higher than that of the resting state when the exercise load was 125 W in both groups. Conclusions:During submaximal exercise, myocardial contractility shows sustained enhancement with the increase of the exercise load. The results of GLS, GCS and GAS indicate that myocardial strain reaches its lowest value under a moderate exercise load, suggesting that moderate exercise can be used to evaluate cardiac function via 3D-SET. Under a simulated lunar gravity of 10° HUT, there is less deformation in the short axis direction of the myocardium, indicating that GCS can be used as a sensitive indicator to detect changes in cardiac function under different gravities.

Objective:To evaluate the efficacy and safety of intrasaccular flow disruptor in wide-necked intracranial aneurysms.Methods:One hundred and seventeen patients with wide-necked intracranial aneurysms treated with intrasaccular flow disruptor were collected from Department of Neurointervention (First Affiliated Hospital of Zhengzhou University), Department of Neurosurgery (Beijing Tiantan Hospital, Capital Medical University), Department of Cerebrovascular Surgery, Neurosurgery Center (Zhujiang Hospital, Southern Medical University), and Department of Neurosurgery (First Affiliated Hospital of Harbin Medical University) from August 2022 to March 2024. Raymond-Roy Occlusion Classification (RROC) was employed to evaluate aneurysm embolization immediately after procedure; cranial CT or MRI within 48 hours of embolization were performed to identify any new intracranial hemorrhage, subarachnoid hemorrhage, or new symptomatic cerebral infarction related to the intracranial aneurysms. Modified Rankin Scale (mRS) was used to assess the neurological function at discharge. Imaging follow-up and outpatient follow-up were performed at 6 months after embolization to evaluate the aneurysm occlusion degree and complications.Results:A total of 117 intrasaccular flow disruptors were implanted in 117 patients, with a technical success rate of 100%; 115 patients (98.3%) enjoyed successful one-time release of their disruptors, and 2 patients (1.7%) required retrieval and redirection of the disruptors before second successful attempt. Flow disruptor plus stent was performed in 13 patients (11.1%). Immediately after procedure, RROC grading I was noted in 3 patients, grading II in 51 patients and grading III in 63 patients. Cranial CT or MRI within 48 hours of embolization indicated no new intracranial hemorrhage, subarachnoid hemorrhage, or symptomatic cerebral infarction related to the intracranial aneurysms. All patients had mRS score of 0 at discharge. Eighty-three patients completed a 6-month follow-up (RROC grading I in 41 patients, grading II in 33 patients and grading III in 9 patients), without ischemic or hemorrhagic adverse events.Conclusion:The results of this study preliminarily suggest that intrasaccular flow disruptor is effective and safe in wide-necked intracranial aneurysms.

Objective:To evaluate the efficacy and safety of Neuroform Atlas stent-assisted coil embolization in patients with middle cerebral artery bifurcation aneurysms.Methods:A retrospective analysis was performed; the clinical data of 46 patients with middle cerebral artery bifurcation aneurysms accepted Neuroform Atlas stent-assisted coil embolization in First Affiliated Hospital of Zhengzhou University, Beijing Tiantan Hospital Affiliated to Capital Medical University, First Affiliated Hospital of Harbin Medical University, Zhujiang Hospital of Southern Medical University and First Affiliated Hospital of Chongqing Medical University from January 2022 to March 2024 were collected. There were 28 ruptured aneurysms (60.87%) and 18 unruptured aneurysms (39.13%). Follow-up was performed for more than 3 months; Raymond-Roy grading was used to evaluate the aneurysm embolization immediately after embolization and during follow-up; perioperative hemorrhagic or ischemic complications were recorded; modified Rankin Scale (mRS) was used to evaluate the prognosis of the patients at discharge and during follow-up (mRS score≤2: good prognosis, and mRS score>2: poor prognosis).Results:Coil embolization was successful in all 46 patients. DSA immediately after embolization showed that 41 patients (89.13%) had completely occluded aneurysms (Raymond-Roy grading I), 2 patients (4.35%) had residual aneurysm neck (Raymond-Roy grading Ⅱ) and 3 patients (6.52%) had partially occluded aneurysms (Raymond-Roy grading Ⅲ). Perioperative complications occurred in 5 patients, including 2 with postoperative cerebral infarction, 1 with hydrocephalus, 1 with postoperative pneumonia leading to respiratory failure, and 1 with stent thrombosis during embolization. Both at discharge and 3 months after embolization, 43 patients (93.48%) had good prognosis and 3 patients (6.52%) had poor prognosis. No obvious ischemic complications (such as stent restenosis) or hemorrhagic complications (such as re-rupture of the aneurysms) were found in all patients. Thirty patients (65.22%) had imaging follow-up for 6-12 months: 26 (86.67%) had Raymond-Roy grading I, 3 (10.00%) had Raymond-Roy grading II, and 1 (3.33%) had Raymond-Roy grading III.Conclusion:Neuroform Atlas stent-assisted coil embolization has good short-term efficacy and high safety in middle cerebral artery bifurcation aneurysms, but long-term follow-up observation is still needed to verify its efficacy.

Objective:To investigate the effects of 10° head up tilt bed rest (HUT) on human cardiac function via 3D speckle tracking echocardiography (3D-STE), and to study the difference in cardiac function under the submaximal exercise load between the horizontal position and 10° HUBR.Methods:Thirty young healthy volunteers were recruited as the subjects, who were randomly divided into an 10° HUT exercise group and horizontal exercise group with 15 subjects in each. Subjects in both groups were asked to ride the bicycle ergometer in the 10° HUBR position and supine position respectively. The load started with 50 W and was increased by 25 W every 3 min until it reached the maximum of 125 W. Before the exercise (resting state), 1 min after the load was increased each time, and 3 min after exercise (recovery period), the following indices were collected: ①basic cardiac function indices: heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), ②conventional cardiac ultrasound indices: left ventricular ejection fraction (LVEF), stroke volume (SV) and cardiac output (CO), ③left ventricular strain indices: global longitudinal strain (GLS), global circumferential strain (GCS), and global area strain (GAS) measured by 3D-SET. The changes of these indices in the 2 groups of subjects under different exercise loads were observed.Results:The differences in the major effect of the basic heart indices (HR, SBP and DBP), conventional cardiac ultrasound indices (LVEF, SV and CO) and left ventricular strain indices (GLS, GCS and GAS) in response to the exercise load were statistically significant ( F=194.90, 113.66, 17.19, P=0.017, 0.018, 0.001). With the increase of the exercise load, the basic heart indices and conventional cardiac ultrasound indices kept rising, the left ventricular strain indices reached the minimum under a moderate exercise load (75 W), HR, SBP and CO were higher than those of the resting state ( P<0.05 or 0.01). Both LVEF under exercise loads of 75, 100, 125 W and during recovery, and SV under exercise loads of 100, 125 W and during recovery were significantly higher than those of the resting state ( P<0.05 or 0.01), while GLS and GCS under exercise loads of 50, 75, 125 W ( P<0.05 or 0.01), and GAS under exercise loads of 50, 75 W ( P<0.01) were significantly lower. There were statistically significant differences not only in GCS across the groups ( F=4.60, P=0.026) but also in DBP due to the interactions between the grouping and exercise loads ( F=3.13, P=0.031). DBP was higher than that of the resting state when the exercise load was 125 W in both groups. Conclusions:During submaximal exercise, myocardial contractility shows sustained enhancement with the increase of the exercise load. The results of GLS, GCS and GAS indicate that myocardial strain reaches its lowest value under a moderate exercise load, suggesting that moderate exercise can be used to evaluate cardiac function via 3D-SET. Under a simulated lunar gravity of 10° HUT, there is less deformation in the short axis direction of the myocardium, indicating that GCS can be used as a sensitive indicator to detect changes in cardiac function under different gravities.

Objective To construct a prediction model for in-hospital mortality in the elderly(≥65 years)patients undergoing unsynchronous cardioversion in ICU and to evaluate its effectiveness.Methods A retrospective study was conducted on 276 elderly eligible patients in the ICU of the Ninth and the First Medical Centers of Chinese PLA General Hospital between June 2022 and August 2024.According to their clinical outcomes,they were divided into a non-in-hospital dead group(111 cases)and an in-hospital dead group(165 cases).Clinical data were collected,and pre-dictive factors for in-hospital mortality were screened.And then a nomogram prediction model was developed based on the obtained predictive factors,which was evaluated with ROC curve and deci-sion curve analyses.Results When compared to the non-in-hospital dead group,the in-hospital dead group had significantly higher heart rate,ratio of hemodialysis,and levels of alanine amin-otransferase,aspartate aminotransferase,lactate dehydrogenase,alkaline phosphatase,serum cre-atinine,blood glucose,lactate,low base excess,sequential organ failure assessment(SOFA)score,model for end-stage liver disease score,and larger proportions of ventricular fibrillation/flutter and structural heart disease induced by pulseless ventricular tachycardia,and had significantly lower Glasgow Coma Scale(GCS)(P＜0.05).Multivariate logistic regression analysis identified body temperature＞37℃(OR=0.426,95％CI:0.198-0.915,P=0.029),chronic obstructive pulmonary disease(OR=2.333,95％CI:1.217-4.473,P=0.011),GCS score(OR=0.622,95％CI:0.410-0.944,P=0.026),hemoglobin(OR=0.817,95％CI:0.715-0.934,P=0.003),lactate(OR=1.365,95％CI:1.174-1.587,P=0.000),heart rate＞100 bpm(OR=2.757,95％CI:1.397-5.441,P=0.003),and SOFA score(OR=1.112,95％CI:1.032-1.198,P=0.005)as pre-dictors of in-hospital mortality.ROC curve analysis showed an AUC value of above indicators combined together in the prediction was 0.797,with a sensitivity of 76.97％and a specificity of 65.77％.Calibration curve analysis demonstrated good consistency between predicted and observed outcomes.Decision curve analysis indicated favorable clinical utility of the model.Conclusion This study identifies independent risk factors for in-hospital mortality among elderly patients in the ICU who underwent asynchronous cardioversion.Based on these factors,a nomo-gram model is established,demonstrating good discrimination,calibration,and model fit,with high clinical applicability.

Purpose To investigate the predictive value of nomogram based on preoperative CT imaging for predicting programmed cell death receptor ligand 1(PD-L1)expression in patient with lung adenocarcinoma.Materials and Methods A total of 158 patients with lung adenocarcinoma were enrolled in Shenzhen people's Hospital from January 2021 to July 2022,of which 82 were negative for PD-L1 and 76 were positive for PD-L1.They were randomly divided into training set(n=119)and verification set(n=39)according to the proportion of 7:3.The significant characteristics between PD-L1 negative and PD-L1 positive were screened by univariate and multivariate Logistic regression to construct a clinical model.Radiomics features were extracted from preoperative CT images,and then features were screened and modeled.Finally,the combined model was established by clinical factors and radiomics features,which was visualized by nomogram.The diagnostic performance of the model was evaluated using receiver operating characteristic curves and area under the curve(AUC).Results The area under the curve(AUC)of the clinical model composed of carcinoembryonic antigen and vascular convergence sign was 0.774(95%CI 0.687-0.860)and 0.808(95%CI 0.670-0.947)in the training set and validation set,respectively.Through feature screening,the radiomics model was composed of 17 radiomics features,and the AUC of the training and validation sets was 0.837(95%CI 0.764-0.910)and 0.778(95%CI 0.633-0.923).The training set and validation set of the combined model composed of carcinoembryonic antigen,vascular convergence sign and radiomics score were AUC 0.892(95%CI 0.832-0.952)and 0.853(95%CI 0.737-0.968).In the training set,the AUC of the combined model was higher than that of the other two models(Z=-2.640,-2.855,P＜0.05).Conclusion Based on preoperative CT radiomics nomogram,it had high predictive efficacy on the expression of PD-L1 in lung adenocarcinoma and could provide decision-making support for the selection of clinical treatment regimens for lung adenocarcinoma patients.

Objective:To characterize the brain structure of Chinese children with autism spectrum disorder (ASD) using artificial intelligence automatic brain segmentation technique, and to analyze the correlation between the characteristics of the brain structure and the degree of brain development.Methods:A case-control study.The data of 52 children who were diagnosed with ASD according to the diagnostic criteria for ASD in the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition of the United States at the Department of Psychology of Qingdao University Affiliated Women and Children′s Hospital from January 2023 to April 2024 were prospectively analyzed.Meanwhile, 48 gender- and age-matched typically developing (TD) children in Qingdao were also included.The three-dimensional T1 weighted imaging sequences of all patients were obtained using a GE 3.0T magnetic resonance imaging scanner.Automated brain segmentation techniques were used to obtain the standardized volumes of each brain structure (the ratio of the absolute volume of the brain structure to the whole brain volume).Two-independent-samples t and Mann-Whitney U tests were used to compare the standardized volumes of different brain regions between the 2 groups.Pearson and Spearman correlation analyses were used to depict the correlations between volume data of brain areas with significant differences and Gesell Developmental Scale scores. Results:Compared with those in the TD group, the volumes of the left grey matter[25.45%(0.70%) vs.25.16%(1.05%)], the right grey matter [(25.89±0.71)% vs.(25.51±0.73)%], the right lateral orbitofrontal cortex [(0.62±0.03)% vs.(0.59±0.05)%], the right medial orbitofrontal cortex[(0.48±0.04)% vs.(0.46±0.04)%], the right pars triangularis [(0.38±0.07)% vs.(0.35±0.05)%], the left hippocampus [0.22%(0.04%) vs.0.20%(0.02%)], the right hippocampus [0.23%(0.04%) vs.0.22%(0.02%)], the left parahippocampal gyrus [0.15%(0.03%) vs.0.14%(0.02%)], the right parahippocampal gyrus [(0.15±0.02)% vs.(0.14±0.02)%], the left fusiform gyrus [(0.82±0.08)% vs.(0.78±0.08)%], the right superior temporal gyrus [(0.96±0.10)% vs.(0.90±0.09)%], the left insular lobe [(0.54±0.03)% vs.(0.53±0.04)%], the right insular lobe [(0.55±0.03)% vs.(0.53±0.04)%], the right inferior parietal cortex [(1.40±0.16)% vs.(1.33±0.12)%], the right precuneus cortex [(0.99±0.09)% vs.(0.94±0.09)%], the right putamen [(0.37±0.04)% vs.(0.35±0.03)%], the left pallidum [(0.14±0.01)% vs.(0.13±0.01)%], the right pallidum [0.14%(0.02%) vs.0.13%(0.01%)], and the right thalamus [(0.51±0.04)% vs.(0.49±0.03)%] were significantly increased in the ASD group (all P<0.05).Nonetheless, the volumes of the left pericalcarine cortex [(0.19±0.04)% vs.(0.20±0.04)%] and the corpus callosum posterior region [0.05%(0.01%) vs.0.06%(0.01%)] in the ASD group were considerably smaller than those in the TD group (all P<0.05).Correlation analysis showed that the right thalamus volume was negatively correlated with the Gesell-adaptation development quotient in children with ASD ( r=-0.276, P=0.048).The volumes of the left fusiform gyrus and left pericalcarine cortex were negatively correlated with the Gesell-fine motor development quotient in children with ASD ( r=-0.290, P=0.037; r=-0.368, P=0.007). The right precuneus cortex volume was negatively correlated with the Gesell-personal and social competence development quotient in children with ASD ( r=-0.396, P=0.007). Conclusions:Children with ASD show abnormalities in the volumes of multiple brain regions, and some brain regions are related to the degree of brain development.Automatic brain segmentation technology based on artificial intelligence can rapidly and directly measure and display the volume of brain structures in both ASD and TD children.

Objective·To evaluate the relationships between disc-condyle distance and anterior disc displacement,as well as between disc-condyle distance and disc morphology,in patients with temporomandibular disorders(TMD)using magnetic resonance imaging(MRI)of the temporomandibular joint(TMJ).Methods·From September 2023 to March 2024,90 patients(180 TMJs)who visited the TMJ clinic of Department of Stomatology,The Second Affiliated Hospital of Anhui Medical University,with clinical symptoms of TMD and were diagnosed via MRI with either anterior disc displacement or no significant displacement,were included.Clinical data were collected,and MRI images were used to measure the angle of disc displacement,disc-condyle distance,disc length,and thickness.The degree of disc deformation was assessed.The relationships between clinical symptoms and anterior disc displacement,between anterior disc displacement and both disc morphology and disc-condyle distance,and between disc-condyle distance and disc morphology were analyzed.Results·Among the 90 patients,there were 16 males and 74 females,with a mean age of(28.1±14.5)years.Among the 180 TMJs,175 had clinical symptoms and 5 were asymptomatic.There were 40 joints with no displacement,78 with reducible anterior disc displacement,and 62 with irreducible anterior disc displacement.In the joints with irreducible anterior disc displacement,the proportion of those with two or more symptoms was slightly higher at 62.9%,but the difference was not statistically significant compared with the joints with no displacement or reducible anterior disc displacement.MRI assessment revealed that in the joints with irreducible anterior disc displacement,the proportion of disc deformation type Ⅲ or higher was significantly higher compared with the non-displaced joints(P<0.001).The disc length was significantly shorter(P<0.001),and the intermediate zone thickness was significantly greater(P<0.001)compared with the non-displaced joints.The disc displacement angles at centric closure and maximum opening were also significantly larger(P<0.001).The disc-condyle distance was 3.10(2.70,3.70)mm for non-displaced joints,3.40(3.00,4.00)mm for joints with reducible anterior disc displacement,and 6.60(4.78,7.90)mm for joints with irreducible anterior disc displacement,with significant differences(P<0.001).The disc-condyle distance was 3.10(2.80,3.60)mm for type Ⅰ discs,3.70(3.10,4.60)mm for type Ⅱ discs,5.10(4.00,7.30)mm for type Ⅲ discs,and 6.80(4.98,8.20)mm for type Ⅳ/Ⅴ discs,with significant differences(P<0.001).The disc-condyle distance was negatively correlated with disc length(rs=-0.469,P<0.001),positively correlated with intermediate zone thickness(rs=0.319,P<0.001),and positively correlated with disc displacement angle at centric closure(rs=0.626,P<0.001).Conclusion·With increasing severity of disc deformation,intermediate zone thickness,and disc displacement angle at centric closure,as well as decreasing disc length,the disc-condyle distance increases.The disc-condyle distance is an important indicator for MRI assessment of pathological changes in TMD.