Objective To establish a finite element model of the hallux valgus foot and study the stress and displacement changes in the first and second rays of the hallux valgus under different tensile forces.Methods Foot CT images of a patient with hallux valgus were imported into Mimics to reconstruct a three-dimensional(3D)skeletal model of the foot.The 3-matic software was used to mesh the reconstructed model and generate the volume mesh.The optimized model was imported into ANSYS for finite element analysis.The relationship between the tensile forces and the stress/displacement of the first and second rays of the hallux valgus was verified by changing the size and direction of the tensile forces.Results Tensile forces of different magnitudes and directions were applied to the first proximal phalanx.When the force was less than 12 N,with an increase in tension,the displacement of the first phalange changed more significantly.For every 2 N increase in tension,the displacement increased by approximately 1 mm.When the force was greater than 12 N,with an increase in tension,the stress on the first phalange increased,whereas the displacement only changed slightly.In addition,when the magnitude of the force remained unchanged at 12 N and the direction of the force changed at intervals of 15°,the stress and stress distributions of the first and second rays changed with direction,and the displacement also changed accordingly.When the direction of the force was perpendicular to that of the second phalanx,the displacement of the first phalanx increased.Conclusions Finite element analysis technology can vividly and accurately analyze the stress and displacement changes of the first and second rays of hallux valgus under different tensile forces,and it lays a foundation for the design of hallux valgus orthoses.

Objective:To study the impact of changes in distance from the point source to the detector lead grid phantom surface on the intrinsic spatial resolution and linearity of single photon emission computed tomography equipment (SPECT), and to provide references for exploring quality control performance testing method.Methods:The intrinsic spatial resolution and linearity indexes of the dual detectors of the two SPECT machines(model 1, 2) were examined using the parallel slit lead grid phantom method, respectively, at five different positions of the vertical distance from the point source to the surface of the lead grid phantom, namely, 150, 170, 190, 210 and 230 cm.Results:After completion of image acquisition about the two SPECT machines with dual detectors at the five positions, the software-based calculated intrinsic spatial resolution and linearity in x and y direction fluctuated both within a very small range: effective field of view half-width half-maximum 3.310-3.902 mm, central field of view half-width half-maximum 3.274-3.910 mm, UFOV differential linearity (0.059-0.180 mm), FUOV absolute linearity (0.171-0.628 mm), CFOV differential linearity (0.046-0.165 mm), CFOV absolute linearity (0.115-0.534 mm). The intrinsic spatial resolution was slightly poor at a source distance of 150 cm. The UFOV FWHM detection value of two machines was (3.80±0.07)mm, with a range of 3.695-3.902 mm. The CFOV FWHM detection value was (3.73±0.11) mm, with a range of 3.572-3.910 mm. However, no statistically significant difference was found in inherent spatial resolution between model 1 and model 2 ( P>0.05). Under the WS 523-2019, the intrinsic spatial resolution and linearity of two machines with dual detectors were both qualified. The comparison of inherent spatial linearity between model 1 and model 2 showed that model 1 was inferior to model 2, with statistically significant difference ( t=15.09, P<0.001). Conclusions:There was no variation in intrinsic spatial resolution and linearity with the source distance when the vertical distance from the point source to the surface of the detector lead grid phantom was changed (150 to 230 cm). When intrinsic spatial resolution and linearity testing were performed on SPECT, it is necessary to ensure that the vertical distance from the point source to the detector is greater than 150 cm and recommended to be at least 170 cm.

Objective:To study the impact of changes in distance from the point source to the detector lead grid phantom surface on the intrinsic spatial resolution and linearity of single photon emission computed tomography equipment (SPECT), and to provide references for exploring quality control performance testing method.Methods:The intrinsic spatial resolution and linearity indexes of the dual detectors of the two SPECT machines(model 1, 2) were examined using the parallel slit lead grid phantom method, respectively, at five different positions of the vertical distance from the point source to the surface of the lead grid phantom, namely, 150, 170, 190, 210 and 230 cm.Results:After completion of image acquisition about the two SPECT machines with dual detectors at the five positions, the software-based calculated intrinsic spatial resolution and linearity in x and y direction fluctuated both within a very small range: effective field of view half-width half-maximum 3.310-3.902 mm, central field of view half-width half-maximum 3.274-3.910 mm, UFOV differential linearity (0.059-0.180 mm), FUOV absolute linearity (0.171-0.628 mm), CFOV differential linearity (0.046-0.165 mm), CFOV absolute linearity (0.115-0.534 mm). The intrinsic spatial resolution was slightly poor at a source distance of 150 cm. The UFOV FWHM detection value of two machines was (3.80±0.07)mm, with a range of 3.695-3.902 mm. The CFOV FWHM detection value was (3.73±0.11) mm, with a range of 3.572-3.910 mm. However, no statistically significant difference was found in inherent spatial resolution between model 1 and model 2 ( P>0.05). Under the WS 523-2019, the intrinsic spatial resolution and linearity of two machines with dual detectors were both qualified. The comparison of inherent spatial linearity between model 1 and model 2 showed that model 1 was inferior to model 2, with statistically significant difference ( t=15.09, P<0.001). Conclusions:There was no variation in intrinsic spatial resolution and linearity with the source distance when the vertical distance from the point source to the surface of the detector lead grid phantom was changed (150 to 230 cm). When intrinsic spatial resolution and linearity testing were performed on SPECT, it is necessary to ensure that the vertical distance from the point source to the detector is greater than 150 cm and recommended to be at least 170 cm.

Objective:To investigate the effect of insular involvement on the outcomes of patients with acute anterior circulation ischemic stroke.Methods:Patients with acute anterior circulation ischemic stroke admitted to the Department of Neurology, Nanjing Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2015 to December 2020 were retrospectively included. Demographic data, vascular risk factors, clinical and laboratory data, as well as treatment and outcomes were collected. Firstly, the correlation between the insular involvement and the outcomes was investigated, and then the bootstrap method was used to clarify the mediating role of infarct volume between the insular involvement and the poor outcomes.Results:A total of 450 patients with acute anterior circulation ischemic stroke were enrolled, among whom 79 cases (17.6%) had insular involvement and 41 (9.1%) had left insular involvement. There were 111 (24.7%) with poor outcomes, including 5 (1.1%) died. Compared to the non-insular involvement group, the insular involvement group had a higher proportion of patients with atrial fibrillation, shorter onset to door time, higher neutrophil-to-lymphocyte ratio (NLR), higher National Institutes of Health Stroke Scale (NIHSS) score at admission, larger infarct volume, and higher proportion of patients with poor outcomes (all P<0.05). In addition, patients with left insular involvement were younger than those with right insular involvement, had a higher baseline NIHSS score, a lower proportion of patients with minor stroke (NIHSS score ≤8), and had a longer onset to door time (all P<0.05). Compared to the good outcome group, the poor outcome group was older, with a higher proportion of female patients, higher systolic blood pressure, blood glucose, NLR, and NIHSS scores at admission, larger infarct volume, and a higher proportion of patients with insular involvement (all P<0.05). Mediation analysis suggested that the mediating effect of infarct volume between the insular involvement and the poor outcomes was significant (95% confidence interval 0.033-0.230; P=0.008). Conclusions:insular involvement in patients with acute anterior circulation ischemic stroke is associated with the poor outcomes, and this association may be mediated by infarct volume. Patients with left insular involvement may have more severe symptoms than those with right insular involvement, but there is no significant difference in the outcomes.

Objective To investigate the efficacy and safety of endovascular recanalization 6-24 h after onset in patients with acute basilar artery occlusion,and explore the related factors for their prognoses.Methods Clinical data of 37 patients with acute basilar artery occlusion,received endovascular recanalization in our hospital from January 2016 to July 2019,were retrospectively collected;23 patients were into group of onset-to-puncture time (OPT)＞6 h (6-24 h),and 14 patients were into group of OPT ≤ 6 h (0-6 h).Statistical methods were used to compare the postoperative symptomatic intracranial hemorrhage rate,good prognosis rate (modified Rankin scale [mRS] scores ≤ 3) and mortality 3 months after onset between the two groups;clinical data between the subgroups with good and poor prognoses in patients of group of OPT＞6 h were compared.Results The postoperative symptomatic intracranial hemorrhage rate,and good prognosis rate and mortality of patients from group of OPT＞6 h were 30.4％,47.8％ and 43.5％,respectively;and there were no statistically significant differences as compared with those in patients from group of OPT≤6 h (35.7％,35.7％,and 42.9％,P＞0.05).Scores of scales based on preoperative CTA images (posterior circulation-Alberta stroke program early CT scale [pc-ASPECTS],scale of posterior circulation on CTA [pc-CTA],and scale of basilar artery on CTA [BATMAN]) showed significant differences between the good prognosis subgroup and poor prognosis subgroup in patients fiom group of OPT＞6 h (P＜0.05).Conclusion Endovascular recanalization 6-24 h after onset is effective in patients with acute basilar artery occlusion,and the safety does not obviously decrease;scores of pc-ASPECTS,pc-CTA and BATMAN may be related to the clinical prognoses.

Acute basilar artery occlusion (ABAO) has a high rate of disability and mortality, and the key to its treatment is to start reperfusion therapy as early as possible. A number of retrospective studies have found that the good prognosis rate of endovascular treatment of ABAO is related to number of infarction locus, extent of ABAO, vascular occlusion and collateral circulation. Screening patients through imaging evaluation before endovascular treatment may further improve the rate of favorable outcome. This article reviews research progress on the correlation between imaging evaluation before endovascular treatment of ABAO and clinical prognoses.