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Objective:To investigate specificity of neurovascular compression in patients with primary trigeminal neuralgia (PTN) by three-dimension reconstruction and computational fluid dynamics.Methods:Clinical characteristics and preoperative magnetic resonance imaging (MRI) data of 20 patients with both PTN and single artery compression (PTN group) and 10 patients without PTN but having neurovascular contact in MRI images (control group) in the Second Affiliated Hospital of Zhengzhou University from January 2018 to December 2019 were collected and analyzed. After three-dimension reconstruction of the MRI images, curvature of the arterial loop, angle between the plane of arterial loop and the trigeminal nerve and location of the compression were observed. Then bidirectional structure-fluid coupling based on the optimized stereolithography models of arterial loop and nerve were processed by ANSYS 19.2 software. In the location of the compression of contact, equivalent stress (ES) of arterial loop on the nerve, shearing stress (SS) of the blood flow and local deformation of the nerve were iteratively computed. All parameters were analyzed and compared between the PTN group and the control group, and the correlation analysis was proceeded between the anatomical parameters and hemodynamical parameters.Results:The curvature of arterial loop [0.21(0.12) mm -1vs 0.13(0.07) mm -1, U=34.00, P<0.05], the angle between vascular loop and nerve [69.70(30.67)° vs 43.40(37.21)°, U=38.00, P<0.05] in the PTN group were significantly greater than those in the control group, and the location of compression was significantly closer to the root of nerve in the PTN group [PTN group: (4.23±1.29) mm vs control group: (5.54±1.85) mm, t=-2.26, P<0.05]. The average SS [15 952.48(5 365.56) Pa vs 12 501.97(6 355.26) Pa, U=53.00, P<0.05], ES [24 965.65(7 693.22) Pa vs 14 992.99(9 824.08) Pa, U=32.00, P<0.05] in the PTN group were significantly greater than those in the control group. The curvature of arterial loop was positively correlated with the SS ( r=0.931, P<0.05) and ES ( r=0.962, P<0.05), and the latter two ( r=0.787, P<0.05; r=0.853, P<0.05) were positively correlated with the local neural deformation. Conclusions:In patients with PTN, offending artery compresses the root of nerve by greater arterial curvature and angle between the arterial loop and nerve. These anatomical differences will cause significantly greater SS, ES and local neural deformation.
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Purpose Full-term fetal weight is closely related to the choice of delivery mode and perinatal mortality rate.Our aim is to explore the feasibility of magnetic resource image (MRI) with three-dimensional reconstruction and volume measurement in estimating fetal weight and its accuracy compared to ultrasound (US) examination.Materials and Methods Analyzed the MRI volume measurement of 61 fetuses delivered within 7 days after M RI and ultrasound examination in our hospital between November 2013 and March 2016 using MRI three-dimensional reconstruction.The fetal weight estimated by MRI was calculated by the equation developed by Baker et al and the US estimation of fetal weight was performed according to Haldlock et al,the MRI and US estimation of fetal weight were compared.Results 60 fetuses were included and qualified MRI three-dimensional reconstruction models,one was excluded because of frequent movement.The MRI estimation of fetal weight and the birth weight correlated significantly (r=0.927,P＜0.05).The MRI estimation of fetal weight had a lower percentage of random error than US (3.4％ vs 5.0％,P＞0.05),as well as mean absolute error [(172+ 114) g vs (227± 171) g,P＜0.05],but a higher percentage of relative error ≤ 10％ than US (95.0％ vs 78.3％,P＜0.05),with an underestimation in 90.0％ fetuses compared with birth-weight.Concision Full-term fetal weight estimation by using MRI with three-dimensional reconstruction and volume measurement is feasible and more accurate than ultrasound,but lower than the actual weight.This method can be applied in estimating fetal weight in the case of ultrasound examination limited.
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Objective To build a three-dimension finite-element model of patella and to make a preliminary mechanics analysis on the model.Methods According to the model-building principle of Ansys software which started from point to line to area to volume,a three-dimension finite-element patella model was reconstructed on the basis of the images of spiral CT.Then,loading on the model patella were simulated and the stress magnitude and distribution on the patella were analyzed.Results Finite element analysis of the patella showed that stress concentration zone located in the middle and lower patella,indicating that fracturepredilectionsitesinthelower patellar.TheVon misesstresson thetensionsidewas significantly greater than that on pressure side.Conclusion The established finite element model of the patella can reflect the real geometry of patella treated in clinics.
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Objective The purpose of this article was to investigate the internal tunnel position during anterior cruciate ligament (ACL) reconstruction with single-bundle ACL. Methods MRI were performed in 10 knees form 10 volunteers at full extension and at 30°, 60°, 90°, and 120° flexion position. All the images obtained were exported into Mimics 10.01. Three-dimensional models were established with Mimics in a computer. All the mark points were confirmed on femur and tibia. The distance between the femoral mark point and tibial mark point was measured. The isometric point was determined as the change in the distance was shorter than 3mm during knee flexion-extension. Results Ten three-dimensional models were established successfully and the isometric points of A0-X, A15-X, A30-X, A45-X, B0-Y, B15-Y, B30-Y, B45-Y, C0-Z, C15-Z, C30-Z, C45-Z, and C60-Z were identified. Conclusion There was no absolute anatomical isometric point, whereas the physiological isometric point did exist. Therefore, determination of tibial point should be considered synthetically. B45-Y was recommended for tunnel position.
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Objective To assess the clinial application of 3D reconstruction with MSCT for acetabular fractures.Methods Volume scanning was performed in 20 patients with acetabular fractures,all data sets were transferred to workstation.Reconstruction were done with more thinner slices.Results Acetabular frature 3D images went all the way with the results of surgery in 17 cases.Conclusion MSCT 3D images can compare beauty with gross specimen,which could be propitious to the subtype of acetabulum fracture and have an advantage in the application.