Powder compaction and sintering are critical stages of powder metallurgy in manufacturing high performance particle reinforced metal matrix composites. In this paper, particulate scale numerical investigations on the warm compaction and solid-state sintering of TiC/316L composite powders with different particle size ratios (PSRs, R316L/RTiC) and TiC contents were performed using multi-particle finite element method (MPFEM) in two dimensions. The effects of PSR and TiC content, compaction pressure and temperature, and sintering temperature on the compaction and sintering processes were comprehensively analyzed. On this basis, a variety of macro- and microscopic analyses were conducted to further identify the densification dynamics and mechanisms. The results indicate that green compacts with higher relative density and more uniform stress distribution can be readily achieved by warm compaction. The large-scale plastic deformation of 316L particles caused by the cooperative actions of temperature and pressure is the main densification mechanism in warm compaction. During solid-state sintering, the improvement of relative density is mainly achieved by the vanishing or shrinkage of residual pores along with the growth of sintering necks, accompanied by the deformation of 316L particles. Large displacements of particles mainly occur in contacting areas of adjacent particles. Moreover, the equivalent stress in 316L particles is smaller than that in TiC particles. With the increase of PSR and TiC content, lower relative density of green compacts and sintered parts were obtained and more irregular morphologies of 316L particles can be observed.

To identify the microstructure evolution and densification behavior of TiC/316L composites in powder metallurgy (PM) process, 3D particulate scale numerical simulations were conducted to reproduce the cold/warm compaction and solid-state sintering of TiC/316L composite powders with corresponding physical experiments being carried out for model validation. The effects of compaction parameters and sintering temperature on the densification behavior of TiC/316L composite powders were systemically investigated. The particle deformation and morphology, stress/strain and microstructure evolutions, and grain size distribution in the whole process were characterized and compared to further illustrate the densification behavior and the underlying dynamics/mechanisms. The results show that compared with the cold compaction, the warm compaction can not only achieve higher relative density, smaller and more uniform equivalent stress, and weaker spring back effect, but also improve the friction condition among powder particles. The plastic deformation of 316L particles is the main densification mechanism during compaction. In the solid-state sintering of TiC/316L compacts, the densification is mainly indicated by shrinkage and vanishing of large residual pores along with the growth of the sintering necks, accompanied by the particle movement and growth along the boundary regions. Meanwhile, the particle displacement and grain size distribution are more uniform in the warm compacted TiC/316L component. Moreover, the equivalent (von Mises) stress in 316L particles is smaller than that in TiC particles.(c) 2022 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights reserved.

Magnetoencephalography (MEG) provides a real-time, non-invasive investigation of brain activity, which is very important for deep understanding of neuroscience. But MEG signals are often contaminated by various artifacts. Signal space separation (SSS) is a technique based on quasi-static Maxwell equations and Laplace equations. It can be used as a spatial filter for MEG signals denoising. In this paper, the SSS spatial filtering is carried out with multi-channel Spin-Exchange Relaxation-Free (SERF) magnetometer equipment for the first time, and the signal fluctuation is significantly reduced after filtering. One automatic method has been developed in this study to find the best SSS parameters based on the Sequential Least Squares Programming. This paper used MNE-pyhton software to generate spatial noise and internal source signal, and compared the denoised signal with internal simulation signal to find the optimal SSS parameters. The experimental results showed that the auditory evoked response was more obvious and the signal-to-noise ratio of the signal is improved in the induced period after SSS filtering.

The hot isostatic pressing (HIP) of Ti6Al4V powders was systematically simulated in two dimensions by using multi-particle finite element method (MPFEM) from particulate scale. Different initial packing structures formed by three kinds of powders (i.e. mono-sized powder, binary powder, and powder with normal size distribution) were firstly constructed. Subsequently, the effects of capsule shape, HIP procedure, temperature, pressure, as well as the powder type on the densification behavior of different Ti6Al4V compacts were investigated and discussed. The macroscopic property like relative density and various microscopic properties such as coordination number, stress/strain distributions of capsule and particles, deformation degree, pore filling behavior, densification mechanism and so on were quantitatively characterized. The results indicate that a larger aspect ratio (AR) is more likely to induce local order packing structure during particle rearrangement, and the proportion of powder particles with more regular deformation of Ti6Al4V compact increases after HIP. The total strain energy and deformation mechanisms of Ti6Al4V compacts are quite different with different HIP procedures. With the rise of temperature, the equivalent total strain of both the capsule and the particles became larger and the equivalent Von Mises stress decreased after HIP. In addition, Ti6Al4V powders with different size ratios will affect the performance of the compact in HIP process. The larger the particle size, the smaller the strain acting on the particle, the closer the roundness of the particle to 1. The Ti6Al4V compacts with different particle size distributions were found to exhibit different densification mechanisms. For packing of mono-sized powder, particle rearrangement destroyed bridging structure and large pores so as to accelerate the densification process. While for the Ti6Al4V compacts formed by binary powder or the powder with normal size distribution, the densification mechanism can be inferred to the extreme deformation of small particles promoting relative rigid motion of large particles.

316L stainless steel (abbreviated by 316L) has been applied in many key industrial areas due to its outstanding properties like corrosion resistance, ductility and biocompatibility etc. However, the relatively low strength and wear resistance of this material restrict its further application. This problem can be solved by the introduction of TiC particulate reinforcement into 316L matrix, which can effectively improve the strength, stiffness, wear resistance and high temperature strength. In the present work, three-dimensional hot pressing (HPing) of TiC-316L composite powders in a closed die is numerically reproduced by multi-particle finite element method from particulate scale. The evolution of macro- and microscopic properties during HPing is systematically characterized and analyzed, and the densification dynamics and mechanisms are identified. The results show that HPing can not only significantly decrease the pressing pressure, but also alleviate the stress concentration in the final compacts. With the increase of pressing temperature, the equivalent von Mises stresses in the compacts get smaller and the equivalent strains of TiC-316L composite powders get larger. During HPing, the voids are mainly filled by particle rearrangement and plastic deformation of 316L particles. Meanwhile, the equivalent von Mises stresses concentrated within the 316L particles firstly increase and then decrease, and the equivalent von Mises stresses concentrated within the TiC particles increase monotonically. Large stresses are mainly concentrated within the TiC particles, which are decreasing from the surface to the center of each particle. Also, larger contact normal forces are mainly distributed within and around the TiC particles.

This paper presents a numerical investigation on the 2D uniaxial die compaction of TiC-316L stainless steel (abbreviated by 316L) composite powders by the multiparticle finite element method (MPFEM). The effects of TiC-316L particle size ratios, TiC contents, and initial packing structures on the compaction process are systematically characterized and analyzed from macroscale and particulate scale. Numerical results show that different initial packing structures have significant impacts on the densification process of TiC-316L composite powders; a denser initial packing structure with the same composition can improve the compaction densification of TiC-316L composite powders. Smaller size ratio of 316L and TiC particles (R316L/RTiC = 1) will help achieve the green compact with higher relative density as the TiC content and compaction pressure are fixed. Meanwhile, increasing TiC content reduces the relative density of the green compact. In the dynamic compaction process, the void filling is mainly completed by particle rearrangement and plastic deformation of 316L particles. Furthermore, the contacted TiC particles will form the force chains impeding the densification process and cause the serious stress concentration within them. Increasing TiC content and R316L/RTiC can create larger stresses in the compact. The results provide valuable information for the formation of high-quality TiC-316L compacts in PM process.

Objective. This pilot study is aimed at investigating the mechanical characteristics of a cast-wrapped fractured forearm and performing a clinical comparative study of our own developed 3D-printed orthopedic cast. Methods. An integrated finite element (FE) model including a forearm and a 3D-printed cast wrapping the forearm was created. The distal radial ulna in this model was cut through to mimic the bone fracture. A 400 N force and 1 Nm rotation moment, which were much larger than the loading conditions encountered in daily life for a human being, were applied on the palm. We conducted a comparative clinical study by using statistical assessment. 60 patients with forearm fractures were selected and treated with manual reduction and external fixation cast. All patients were divided into three groups with equal members (20): (a) 3D-printed external cast group, (b) traditional plaster external fixation group, and (c) splint external fixation group. The clinical efficacy, wrist function, and patient satisfaction were scored and compared. Results. In the condition of 400 N loading, the fracture displacements in anterior-posterior (AP), posterior-anterior (PA), medial to lateral (ML), and lateral to medial (LM) compression directions were 1.2648, 1.3253, 0.8503, and 0.8957 (mm), respectively, and the corresponding fracture stresses were 4.5986, 3.9129, and 5.0334, 7.9197 (MPa), respectively. In the inward (IR) and outward (OR) rotations, the fracture displacements were both 0.02628 (mm), and the corresponding fracture surface stresses were 0.1733 and 0.1723 (MPa), respectively. In the clinical efficacy, wrist function, and patient comfort evaluation, the total scores of group A were both higher than those in groups B and C (P<0.05). Conclusion. A 3D-printed orthopedic cast was capable of exerting appropriate mechanical correction loads on specific areas to maintain optimal alignment of a fractured forearm and thus could achieve the favorable clinical efficacy and patient comfort.

Abnormal structural connectivity of cerebral small-vessel disease (CSVD) is associated with cognitive impairment. But the different characteristics of structural connectivity have not been elucidated in early CSVD patients. The current study aimed to investigate the potential differences of structural connectivity in CSVD patients with mild cognitive impairment (MCI) and CSVD patients with normal cognition. Twenty-two CSVD patients with MCI, 34 CSVD patients with normal cognition, and 35 controls, who were age, sex, and education matched underwent diffusion tensor imaging and high resolution T1-weighted imaging. Clinical characteristics, lacunar infarct volume, white matter hyperintensity (WMH) volume, and global atrophy were quantitatively evaluated. Maps of fiber connectivity density (FiCD) were constructed and compared across groups in vertex levels. Pearson correlation was used to estimate the imaging-clinical relationships with control of general characteristics. CSVD patients with MCI had higher lesion load of WMH and lacunar infarcts, and correspondingly lower global FiCD value than CSVD patients with normal cognition (P < 0.01). Lacunar infarct (r = -0.318, P < 0.01) and WMH (r = -0.400, P < 0.01), but not global atrophy, age, or sex, were significantly correlated with the global FiCD value. CSVD patients with normal cognition showed decreased FiCD value mainly in the prefrontal areas (P < 0.01 with Monte Carlo correction). Compared with CSVD patients with normal cognition, CSVD patients with MCI showed significantly decreased FiCD value in enlarged frontal and parietal areas (P < 0.01 with Monte Carlo correction). Inter-group comparisons showed regional enhanced impairment of connectivity density in CSVD patients with MCI in the left superior frontal gyrus, the left precuneus, and the orbital part of the right inferior frontal gyrus (P < 0.01 with Monte Carlo correction). Regional FiCD value of frontal and parietal areas was associated with the cognitive function (P < 0.01). In conclusion, cognitively normal CSVD patients already have disruptions of structural connectivity. The extent and intensity of connectivity disruptions in frontal and parietal areas may underlie the mechanism of cognitive impairment in CSVD. Fiber connectivity density measurements may be helpful for quantitative description of structural cortical connectivity.

Long-term married couples have been reported to share personality and behavioural similarities, but whether long-term marriage would shape the brain is hitherto unknown. In this study, 35 pairs of long-term married couples, who have married and living together at least 30 years, were recruited, and resting state functional magnetic resonance imaging was used to examine the neural correlates of long-term marriage between couples. Seven intrinsic connectivity networks were extracted using spatially constrained group independent component analysis, and the spatial similarity of each network as well as functional connectome similarity between couples were investigated respectively. The significant spatial similarities in the salience and frontoparietal networks as well as marginally significant connectome similarity were observed in long-term married couples. In addition, the marital duration showed a significantly positive correlation with the spatial similarity in the frontoparietal network and connectome similarity. The results provide objective evidence that long-term marriage would shape brain network organization, and the combination of initial personality traits and long-term common experience of the couples may be potential factors that account for similar brain network organizations between couples.

Amnestic mild cognitive impairment (aMCI) is considered as a transitional stage between the expected cognitive decline of normal aging and Alzheimer’s disease (AD). Structural brain difference has shown the potential in cognitive related diagnosis, however cortical thickness patterns transferred from aMCI to AD, especially in the subtypes of aMCI, is still unclear. In this study, we investigated the cortical thickness discrepancies among AD, aMCI and normal control (NC) entities, especially for two subtypes of aMCI - multiple-domain aMCI (aMCI-m) and single-domain aMCI (aMCI-s). Both region of interest (ROI)-based and vertex-based statistical strategies were performed for group-level cortical thickness comparison. Spearman correlation was utilized to identify the correlation between cortical thickness and clinical neuropsychological scores. The result demonstrated that there was a significant cortical thickness decreasing tendency in fusiform gyrus from NC to aMCI-s to aMCI-m to finally AD in both left and right hemispheres. Meanwhile, the two subtypes of aMCI showed cortical thickness difference in middle temporal gyrus in left hemisphere. Spearman correlation indicated that neuropsychological scores had significant correlations with entorhinal, inferior temporal and middle temporal gyrus. The findings suggested that cortical thickness might serve as a potential imaging biomarker for the differential diagnosis of cognitive impairment.

Objectives: To evaluate white matter hyperintensities (WMH) quantification reproducibility from multiple aspects of view and examine the effects of scan-rescan procedure, types of scanner, imaging protocols, scanner software upgrade, and automatic segmentation tools on WMH quantification results using magnetic resonance imaging (MRI). Methods: Six post-stroke subjects (4 males; mean age = 62.8, range = 58-72 years) were scanned and rescanned with both 3D T1-weighted, 2D and 3D T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) MRI across four different MRI scanners within 12 h. Two automated WMH segmentation and quantification tools were used to measure WMH volume based on each MR scan. Robustness was assessed using the coefficient of variation (CV), Dice similarity coefficient (DSC), and intra-class correlation (ICC). Results: Experimental results show that the best reproducibility was achieved by using 3D T2-FLAIR MRI under intra-scanner setting with CV ranging from 2.69 to 2.97%, while the largest variability resulted from comparing WMH volumes measured based on 2D T2-FLAIR MRI with those of 3D T2-FLAIR MRI, with CV values in the range of 15.62%-29.33%. The WMH quantification variability based on 2D MRIs is larger than 3D MRIs due to their large slice thickness. The DSC of WMH segmentation labels between intra-scanner MRIs ranges from 0.63 to 0.77, while that for inter-scanner MRIs is in the range of 0.63-0.65. In addition to image acquisition, the choice of automatic WMH segmentation tool also has a large impact on WMH quantification. Conclusion: WMH reproducibility is one of the primary issues to be considered in multicenter and longitudinal studies. The study provides solid guidance in assisting multicenter and longitudinal study design to achieve meaningful results with enough power.

Radiomics-based researches have shown predictive abilities with machine-learning approaches. However, it is still unknown whether different radiomics strategies affect the prediction performance. The aim of this study was to compare the prediction performance of frequently utilized radiomics feature selection and classification methods in glioma grading. Quantitative radiomics features were extracted from tumor regions in 210 Glioblastoma (GBM) and 75 low-grade glioma (LGG) MRI subjects. Then, the diagnostic performance of sixteen feature selection and fifteen classification methods were evaluated by using two different test modes: ten-fold cross-validation and percentage split. Balanced accuracy and area under the curve (AUC) of the receiver operating characteristic were used to evaluate prediction performance. In addition, the roles of the number of selected features, feature type, MRI modality, and tumor sub-region were compared to optimize the radiomics-based prediction. The results indicated that the combination of feature selection method L 1 -based linear support vector machine (L 1 -SVM) and classifier multi-layer perceptron (MLPC) achieved the best performance in the differentiation of GBM and LGG in both ten-fold cross validation (balanced accuracy:0.944, AUC:0.986) and percentage split (balanced accuracy:0.953, AUC:0.981). For radiomics feature extraction, the enhancing tumor region (ET) combined with necrotic and non-enhancing tumor (NCR/NET) regions in T1 post-contrast (T1-Gd) modality provided more considerable tumor-related phenotypes than other combinations of tumor region and MRI modality. Our comparative investigation indicated that both feature selection methods and machine learning classifiers affected the predictive performance in glioma grading. Also, the cross-combination strategy for comparison of radiomics feature selection and classification methods provided a way of searching optimal machine learning model for future radiomics-based prediction.

Background: To investigate the feasibility and safety of computed tomography-magnetic resonance imaging (CT-MRI) fusion-guided iodine-125 seed implantation for a single malignant brain tumor. Methods: From November 2015 to October 2016, 12 patients with a single malignant brain tumor were treated with permanent iodine-125 seeds implantation. CT-MRI fusion images were used to make the preoperative treatment plan, intraoperative dose optimization, postoperative verification, and tumor response follow-up. The dosimetry parameters of CT-MRI image fusion plans were compared between preprocedures and postprocedures, including plan target volume, V100 (the percentage of the target volume covered by the prescription dose [PD]), D90 (the dose that covers 90% of the target volume), and V200 (the percentage volume of the brain tumor receiving 200% of the PD). Adverse events were graded by the Common Terminology Criteria for Adverse Events. Clinical and radiological follow-ups were performed at a 3-month interval. Results: All the interstitial implantations were completed successfully under the guidance of CT-MRI image fusion. The dosimetry parameters of CT-MRI image fusion postplans did not differ significantly from those of preplans (P > 0.05). No higher than Grade 2 adverse events were observed during the follow-up. Tumor control was achieved in 10 of 12 patients (83.33%). The median overall survival time was 15.05 +/- 3.35 months (95% confidence interval 12.99-17.26). Conclusions: CT-MRI image fusion is feasible for the design, optimization, and verification of treatment planning. CT-MRI fusion-based brachytherapy may improve dosimetry of brain tumor while sparing the normal structures, potentially impacting disease control, treatment-related toxicity, and long-term survival.

OBJECTIVES:To compare micro RNA (miRNA) expression: (a) between healthy individuals and early rheumatoid arthritis (ERA) patients with and without erosion on high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline; and (b) to explore whether these miRNAs could inform a signature predictive of erosion progression despite treatment with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs).METHODS:The second metacarpophalangeal head (MCP2) was scanned by HR-pQCT at baseline and 1 year in 117 ERA patients. We performed global profiling of 377 miRNAs in 10 ERA patients with and without erosion on HR-pQCT at baseline and six healthy controls. Validation of the miRNAs of interest were conducted using TaqMan® quantitative real-time polymerase chain reaction in the validation ERA cohort (n = 117) at baseline. Correlation between the candidate miRNAs and erosion progression over 1 year were also assessed.RESULTS:In the 377 screened miRNAs, 94 (60.6%) miRNAs were upregulated in patients with erosions, with 13 (8.4%) upregulated more than 2-fold. Sixty-one (39.4%) miRNAs were downregulated in patients with erosions, with 6 (3.9%) downregulated more than 2-fold. Expression of miR-143-3p, miR-145-5p and miR-99b-5p were significantly higher in the plasma of ERA patients with erosions compared with those without erosions. Logistic regression analysis revealed that the baseline expression of miR-99b-5p was an independent predictor of erosion progression at month 12 (Exp [B] = 4.257, 95% CI 1.178-15.386, P = 0.027).CONCLUSIONS:Differential expressions of circulating miR-143-3p, miR-145-5p and miR-99b-5p in the plasma of ERA patients may characterize a severe form of the disease. MiR-99b-5p, in particular, may serve as a possible predictor for erosion progression.

The whole-brain atrophy profiles in single- (aMCI-s) and multi- (aMCI-m) domain amnestic mild cognitive impairment (aMCI) remain unclear so far. It is of particular interest to test whether the volume of hippocampus and amygdala can be used to dissociate from these two aMCI subtypes. Magnetic resonance imaging (MRI) data was acquired from 270 elder subjects (aged 68.1 ± 8.7 years), including AD (n = 90), aMCI (n = 90, with 27 aMCI-s and 22 aMCI-m) and normal controls (NC, n = 90) subjects. Also, 23 AD and 23 NC (n = 23) matched in demography were selected for the subgroup analysis. AccuBrain® was used for automated regional brain volumetry. Regional brain volume ratio was used for group comparisons, which was defined as the ratio of the regional volume to the intracranial volume (ICV). Group comparisons of brain volumetry were performed using Student's t test and one-way analysis of variance (ANOVA) followed by Turkey's post hoc test where appropriate. FDR-adjusted P-values < 0.05 were considered significant. Both the overall analysis and subgroup analysis indicated significant positive correlations between cognitive function assessed by Mini–Mental State Examination (MMSE) and all examined regional volume fractions, as well as significant negative correlations between MMSE scores and all examined ventricular volume fractions. There were also negative correlations between MMSE scores and all lobar atrophy measures in both analyses, with only the occipital lobe and parietal lobe nonsignificant in the subgroup analysis. Significant volumetric differences for all regional measures were also identified among AD, aMCI and NC. In the subgroup analysis, left frontal lobe, left temporal lobe and total brain parenchyma were found with significant volumetric differences between aMCI-s and AD, and left temporal lobe and brain parenchyma were found with significant volumetric differences between aMCI-m and NC.

Objectives: To investigate the efficacy of two tight-control treatment strategies aimed at simplified disease activity score [SDAI] remission (SDAI <= 3.3) compared to DAS28 remission (DAS28 < 2.6) on progression of bone erosions in early rheumatoid arthritis (ERA) patients using high-resolution peripheral quantitative computed tomography (HR-pQCT). Methods: This was an open-label study in which 80 early RA patients were randomized to receive 1-year of tight-control treatment. Group 1 (n = 37) aimed at SDAI <= 3.3 and group 2 (n = 43) aimed at DAS28-CRP < 2.6. The number and size of bone erosions, as well as the bone mineral density (BMD) surrounding bone erosion at the second metacarpophalangeal joint (MCP2), were measured at baseline and 12 months. Results: After 12 months, images were analyzed in 63 patients. Changes in clinical parameters, number and size of bone erosions as well as the BMD surrounding bone erosion between the two treatment groups were similar. Therefore, a post-hoc analysis including all 63 patients was performed to elucidate the independent predictors of erosion progression and repair. Multivariate analysis revealed that not achieving sustained SDAI remission at month 6, 9 and 12 (p = 0.034) and rheumatoid factor > 16U (p = 0.021) were independent predictors associated with an increase in erosion volume. Logistic regression analysis showed that achieving sustained SDAI remission (p = 0.043) was associated with partial erosion repair. Conclusions: Although more stringent treatment target did not notably affect clinical treatment outcome and erosion progression at 1 year, achieving sustained SDAI remission was found to be associated with partial erosion repair. (C) 2018 Elsevier Inc. All rights reserved.

Acute ischemic stroke is recognized as a common cerebral vascular disease in aging people. Accurate diagnosis and timely treatment can effectively improve the blood supply of the ischemic area and reduce the risk of disability or even death. Understanding the location and size of infarcts plays a critical role in the diagnosis decision. However, manual localization and quantification of stroke lesions are laborious and time-consuming. In this paper, we propose a novel automatic method to segment acute ischemic stroke from diffusion weighted images (DWIs) using deep 3-D convolutional neural networks (CNNs). Our method can efficiently utilize 3-D contextual information and automatically learn very discriminative features in an end-to-end and data-driven way. To relieve the difficulty of training very deep 3-D CNN, we equip our network with dense connectivity to enable the unimpeded propagation of information and gradients throughout the network. We train our model with Dice objective function to combat the severe class imbalance problem in data. A DWI data set containing 242 subjects (90 for training, 62 for validation, and 90 for testing) with various types of acute ischemic stroke was constructed to evaluate our method. Our model achieved high performance on various metrics (Dice similarity coefficient: 79.13%, lesionwise precision: 92.67%, and lesionwise F1 score: 89.25%), outperforming the other state-of-the-art CNN methods by a large margin. We also evaluated the model on ISLES2015-SSIS data set and achieved very competitive performance, which further demonstrated its generalization capacity. The proposed method is fast and accurate, demonstrating a good potential in clinical routines.

BACKGROUND AND PURPOSE:Neural system was one of the important contributors to the etiopathogenesis of adolescent idiopathic scoliosis; additionally, the morphology of corpus callosum interconnecting both hemispheres of the brain was found to be altered morphologically. Our aim was to evaluate and compare the microstructural changes of the corpus callosum and its interhemispheric white matter fiber tracts interconnecting both cerebral hemispheres in patients with adolescent idiopathic scoliosis and matched controls using diffusion tensor imaging.MATERIALS AND METHODS:Brain DTI was performed in 69 patients with adolescent idiopathic scoliosis (female, right thoracic/thoracolumbar curve) and 40 age-matched controls without adolescent idiopathic scoliosis (female). 2D and 3D segmentation of the corpus callosum were performed using a region-growing method, and the corpus callosum was further divided into 6 regions, including the rostrum, genu, anterior and posterior midbodies, isthmus, and splenium. The laterality index was calculated to quantify the asymmetry of the corpus callosum. Interhemispheric fiber tractography were performed using the Brodmann atlas.RESULTS:2D ROI analysis revealed reduced fractional anisotropy in the genu and splenium (P = .075 and P = .024, respectively). Consistently reduced fractional anisotropy on the left sides of the genu and splenium was also found in 3D ROI analysis (P = .03 and P = .012, respectively). The laterality index analysis revealed a pseudo-right lateralization of the corpus callosum in adolescent idiopathic scoliosis. Interhemispheric fibers via the splenium interconnecting Brodmann 3, 1, and 2; Brodmann 17; and Brodmann 18 (corresponding to the primary somatosensory cortex and primary and secondary visual cortices) were also found to have reduced fractional anisotropy (P ≤ .05).CONCLUSIONS:Reduced fractional anisotropy was found in the genu and splenium of the corpus callosum and corresponding interhemispheric fiber tracts interconnecting the somatosensory and visual cortices via the splenium. Our results are suggestive of altered white matter microstructure within the brain of those with adolescent idiopathic scoliosis, which could be related to abnormal brain maturation during adolescence in adolescent idiopathic scoliosis and could possibly explain the previously documented somatosensory function impairment and visuo-oculomotor dysfunction in this condition.