OBJECTIVES: We present a new low-dose CT reconstruction method using sub-pixel and anisotropic diffusion. METHODS: The sub-pixel intensity values and their second-order differences were obtained using linear interpolation techniques, and the new gradient information was then embedded into an anisotropic diffusion process, which was introduced into a penalty-weighted least squares model to reduce the noise in low-dose CT projection data. The high-quality CT image was finally reconstructed using the classical filtered back-projection (FBP) algorithm from the estimated data. RESULTS: In the Shepp-Logan phantom experiments, the structural similarity (SSIM) index of the CT image reconstructed by the proposed algorithm, as compared with FBP, PWLS-Gibbs and PWLS-TV algorithms, was increased by 28.13%, 5.49%, and 0.91%, the feature similarity (FSIM) index was increased by 21.08%, 1.78%, and 1.36%, and the root mean square error (RMSE) was reduced by 69.59%, 18.96%, and 3.90%, respectively. In the digital XCAT phantom experiments, the SSIM index of the CT image reconstructed by the proposed algorithm, as compared with FBP, PWLS-Gibbs and PWLS-TV algorithms, was increased by 14.24%, 1.43% and 7.89%, the FSIM index was increased by 9.61%, 1.78% and 5.66%, and the RMSE was reduced by 26.88%, 9.41% and 18.39%, respectively. In clinical experiments, the SSIM index of the image reconstructed using the proposed algorithm was increased by 19.24%, 15.63% and 3.68%, the FSIM index was increased by 4.30%, 2.92% and 0.43%, and the RMSE was reduced by 44.60%, 36.84% and 15.22% in comparison with FBP, PWLS-Gibbs and PWLS-TV algorithms, respectively. CONCLUSIONS The proposed method can effectively reduce the noises and artifacts while maintaining the structural details in low-dose CT images.
Tomography, X-Ray Computed/methods* ; Algorithms ; Phantoms, Imaging ; Anisotropy ; Image Processing, Computer-Assisted/methods* ; Humans ; Radiation Dosage

This study aimed to define the most consistent white matter microarchitecture pattern in Parkinson's disease (PD) reflected by fractional anisotropy (FA), addressing clinical profiles and methodology-related heterogeneity. Web-based publication databases were searched to conduct a meta-analysis of whole-brain diffusion tensor imaging studies comparing PD with healthy controls (HC) using the anisotropic effect size-signed differential mapping. A total of 808 patients with PD and 760 HC coming from 27 databases were finally included. Subgroup analyses were conducted considering heterogeneity with respect to medication status, disease stage, analysis methods, and the number of diffusion directions in acquisition. Compared with HC, patients with PD had decreased FA in the left middle cerebellar peduncle, corpus callosum (CC), left inferior fronto-occipital fasciculus, and right inferior longitudinal fasciculus. Most of the main results remained unchanged in subgroup meta-analyses of medicated patients, early stage patients, voxel-based analysis, and acquisition with 30 diffusion directions. The subgroup meta-analysis of medication-free patients showed FA decrease in the right olfactory cortex. The cerebellum and CC, associated with typical motor impairment, showed the most consistent FA decreases in PD. Medication status, analysis approaches, and the number of diffusion directions have an important impact on the findings, needing careful evaluation in future meta-analyses.
Anisotropy ; Brain/diagnostic imaging* ; Corpus Callosum ; Diffusion Tensor Imaging ; Humans ; Parkinson Disease/diagnostic imaging* ; White Matter/diagnostic imaging*

To compare the differences in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) between brucella spondylitis (BS) groups at different stages before treatment and the normal control group and to evaluate the change trend of ADC value and FA value at different time points before and after treatment. Totally 53 patients suspected of BS by conventional magnetic resonance imaging (MRI) and later confirmed as BS patients by serological tests were enrolled in this study. These patients underwent conventional MRI and diffusion tensor imaging scans,and the ADC value and FA value were measured. Independent sample test was used to compare the ADC value and FA value between the BS group and the control group,the ADC value and FA value between the BS group at each stage. Repeated measurement ANOV was used to compare the ADC values and FA values at different time points before and after treatment. FA imaging showed that the color code of BS was different from that of the normal control group,and the color code of FA imaging showed increased singal. The ADC values of BS in the acute,subacute,and chronic stages [(1.45±0.02)×10 mm /s,(1.35±0.03)×10 mm /s,(1.26±0.05)×10 mm /s,respectively] were significantly higher than those in the control group [(1.06±0.09) ×10 mm /s](=2.538,=0.009;=1.998,=0.032;=1.575,=0.004),and the FA value (0.55±0.02,0.65±0.03,0.71±0.04,respectively) were significantly lower than those of the control group (0.78±0.02) (=2.440,=0.012; =1.847,=0.041;=2.102,=0.003). Repeated measurement analysis showed that there were statistically significant differences in ADC values and FA values at different time points before and after treatment in the acute,subacute,and chronic stages (ADC:=12.100,<0.001;=8.439,=0.005;=9.704,=0.004,respectively;FA:=7.080,=0.002;=6.607;=0.003;=8.868,=0.001,respectively). The ADC values at different time points after treatment were significantly lower than those before treatment or at a previous time point after treatment (=332.14,<0.001),and the FA values were significantly higher than those before treatment or at a previous time point after treatment (=134.26,<0.001). FA color code can intuitively display differences in BS and normal vertebral bodies and show change of color code before and after treatment. Also,the ADC values and FA values can quantitatively reveal differences between BS and normal vertebral body in different time points and quantify BS vertebral lesion changes before and after treatment. In particular,in BS patients who are recovering from treatment,it can quantify microscopic edema. Therefore,diffusion tensor imaging may be useful objective indicator in evaluating the effectiveness of a specific treatment for BS.
Anisotropy ; Brucella ; Brucellosis ; diagnostic imaging ; Diffusion Magnetic Resonance Imaging ; Diffusion Tensor Imaging ; Humans ; Spondylitis ; diagnostic imaging ; microbiology

OBJECTIVE: To study the value of fractional anisotropy (FA) of regions of interest (ROI) on magnetic resonance diffusion tensor imaging (DTI) in bilirubin-induced neurological dysfunction in neonates. METHODS: A total of 91 neonates with hyperbilirubinemia who were hospitalized from January 2017 to January 2018 were enrolled. According to the peak level of total serum bilirubin, they were divided into three groups: mild/moderate increase (n=45), severe increase (n=35), and extremely severe increase (n=11). According to the presence or absence of abnormal neurological manifestations, they were divided into two groups: neurological dysfunction (n=20) and non-neurological dysfunction (n=71). Ten healthy full-term infants were enrolled as the control group. Head DTI was performed for all neonates to measure the FA values of the bilateral globus pallidus, the anterior limb of the internal capsule, the posterior limb of the internal capsule, and the cerebellar dentate nucleus. RESULTS: The extremely severe increase group had significantly lower FA values of the globus pallidus than the control, mild/moderate increase, and severe increase groups (P<0.05). The severe increase group had significantly lower FA values of the globus pallidus than the control group (P<0.05). The extremely severe increase group had significantly lower FA values of the posterior limb of the internal capsule than the control, mild/moderate increase, and severe increase groups (P<0.05). The neurological dysfunction group had significantly lower FA values of the globus pallidus and the posterior limb of the internal capsule than the non-neurological dysfunction group (P<0.05). CONCLUSIONS Serum bilirubin level combined with the changes in the DTI FA values of the globus pallidus and the posterior limb of the internal capsule can be used to predict the injury of cerebral nuclei and white matter fibers.
Anisotropy ; Bilirubin ; Brain ; Diffusion Magnetic Resonance Imaging ; Diffusion Tensor Imaging ; Humans ; Infant, Newborn ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; White Matter

OBJECTIVE: We aimed to investigate the ability of readout-segmented echo-planar imaging (rs-EPI)-based diffusion tensor imaging (DTI) in assessing the microstructural change of extraocular muscles (EOMs) and optic nerves in patients with thyroid-associated orbitopathy (TAO) as well as in evaluating disease activity.MATERIALS AND METHODS: We enrolled 35 TAO patients and 22 healthy controls (HCs) who underwent pre-treatment rs-EPI-based DTI. Mean, axial, and radial diffusivity (MD, AD, and RD) and fractional anisotropy (FA) of the medial and lateral EOMs and optic nerve for each orbit were calculated and compared between TAO and HC groups and between active and inactive TAO groups. Factors such as age, sex, disease duration, mediation, and smoking history between groups were also compared. Logistic regression analysis was used to evaluate the predictive value of significant variables for disease activity.RESULTS: Disease duration was significantly shorter in active TAOs than in inactive ones (p < 0.001). TAO patients showed significantly lower FA and higher MD, AD, and RD than HCs for both medial and lateral EOMs (p < 0.001), but not the AD value of lateral EOMs (p = 0.619). Active patients had significantly higher FA, MD, and AD than inactive patients for medial EOMs (p < 0.005), whereas only FA differed significantly in the lateral EOMs (p = 0.018). The MD, AD, and RD of optic nerves were significantly lower in TAO patients than HCs (p < 0.05), except for FA (p = 0.129). Multivariate analysis showed that the MD of medial EOMs and disease duration were significant predictors for disease activity. The combination of these two parameters showed optimal diagnostic efficiency for disease activity (area under the curve, 0.855; sensitivity, 68.4%; specificity, 96.9%).CONCLUSION: rs-EPI-based DTI is promising in assessing microstructural changes of EOMs and optic nerves and can help to indicate the disease activity of TAO, especially through the MD of medial EOMs.
Anisotropy ; Diffusion Tensor Imaging ; Diffusion ; Echo-Planar Imaging ; Humans ; Logistic Models ; Multivariate Analysis ; Muscles ; Negotiating ; Optic Nerve ; Orbit ; Sensitivity and Specificity ; Smoke ; Smoking ; Troleandomycin

BACKGROUND AND PURPOSE: Cerebral small vessel disease (CSVD) is the most common cause of vascular dementia and a major contributor to mixed dementia. CSVD is characterized by progressive cerebral white matter changes (WMC) due to chronic low perfusion and loss of autoregulation. In addition to its antiplatelet effect, cilostazol exerts a vasodilating effect and improves endothelial function. This study aims to compare the effects of cilostazol and aspirin on changes in WMC volume in CSVD.METHODS: The comparison study of Cilostazol and aspirin on cHAnges in volume of cerebral smaLL vEssel disease white matter chaNGEs (CHALLENGE) is a double blind, randomized trial involving 19 hospitals across South Korea. Patients with moderate or severe WMC and ≥ 1 lacunar infarction detected on brain magnetic resonance imaging (MRI) are eligible; the projected sample size is 254. Participants are randomly assigned to a cilostazol or aspirin group at a 1:1 ratio. Cilostazol slow release 200 mg or aspirin 100 mg are taken once daily for 2 years. The primary outcome measure is the change in WMC volume on MRI from baseline to 104 weeks. Secondary imaging outcomes include changes in the number of lacunes and cerebral microbleeds, fractional anisotropy and mean diffusivity on diffusion tensor imaging, and brain atrophy. Secondary clinical outcomes include all ischemic strokes, all vascular events, and changes in cognition, motor function, mood, urinary symptoms, and disability.CONCLUSIONS: CHALLENGE will provide evidence to support the selection of long-term antiplatelet therapy in CSVD.TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01932203
Anisotropy ; Aspirin ; Atrophy ; Brain ; Cerebral Small Vessel Diseases ; Cognition ; Dementia ; Dementia, Vascular ; Diffusion Tensor Imaging ; Homeostasis ; Humans ; Korea ; Magnetic Resonance Imaging ; Outcome Assessment (Health Care) ; Perfusion ; Sample Size ; Stroke ; Stroke, Lacunar ; White Matter

To evaluate the white-matter integrity and its correlation with cognitive function in patients with mild cognitive impairment (MCI) complicated with lacunar infarctions (LI) by diffusion tensor imaging (DTI) of magnetic resonance (MR).
 Methods: Twenty-six patients with MCI were selected including 14 patients with combined LI and 12 patients without combined LI, and 16 healthy volunteers were recruited as normal control. All subjects completed cognitive function assessment and DTI sequence of MR. Factional anisotropy (FA) and mean diffusivity (MD) values among the MCI with LI group (MCI-LI), the MCI without LI group (MCI-non LI), and the normal control group (NC) were compared, and the correlation between DTI parameters and cognition was determined by multiple linear stepwise regression.
 Results: Compared with the MCI-non LI group, the FA values were significantly decreased (P<0.05) and MD values were significantly increased (P<0.05) in the white matter fiber bundles (such as the left hippocampus of the cingulate tract, the frontal fascicle of the corpus callosum, the right inferior frontal occipital fascicle, and the right superior longitudinal fascicle) in the MCI-LI group. In the MCI-LI group, the FA value of right cingulate gyrus was significantly correlated with Activity of Daily Living Scale (ADL) score (B=-50.2, 95% CI -77.7 to -22.7, P=0.003); the FA value of left anterior thalamic radiation (B=443.8, 95% CI 222.9 to 664.8, P=0.001) and MD value of left inferior longitudinal tract (B=-318.5, 95% CI -534.7 to -102.3, P=0.009) were significantly correlated with Wechsler digit symbol substitution (WDSS) score; the FA value of left superior temporal lobe longitudinal tract was significantly correlated with Backward Digit Span (BDSP) score (B=12.5, 95% CI 1.5 to 23.4, P=0.030).
 Conclusion: The integrity of white matter is significantly destroyed in MCI patients with LI than that in MCI patients without LI, and there is a correlation between cognitive function and DTI parameters in some white matter tracts in MCI patients with LI.
Anisotropy ; Brain ; Cognitive Dysfunction ; diagnostic imaging ; Diffusion Magnetic Resonance Imaging ; Diffusion Tensor Imaging ; Humans ; Neuropsychological Tests ; Stroke, Lacunar ; White Matter

To explore the mechanism for changes in brain microstructure in long-term abstinent from methamphetamine-dependence by using the diffusion tensor imaging (DTI).
 Methods: A total of 26 patients with long-term abstinent methamphetamine-dependence, whose abstinence time more than 14 months, and 26 normal controls all underwent cognitive executive function tests and DTI scans. We used voxel-based analysis to compare the fractional anisotropy (FA) and mean diffusivity (MD) to obtain the abnormal brain regions of DTI parameters between the two groups. Spearman correlation analysis was used to explore the correlation between FA, MD of the brain regions with abnormal parameters and cognitive executive function tests.
 Results: There were no statistical differences in the cognitive executive function tests between the two groups (P>0.05). Compared with the normal control group, the long-term abstinent from methamphetamine-dependence group showed the decreased FA in the right precuneus, right superior frontal gyrus, right calcarine, left inferior temporal gyrus and the increased MD in the right triangular part of inferior frontal gyrus, right precuneus, right posterior cingulate, right middle temporal gyrus, bilateral middle occipital gyrus, left superior parietal lobule, and lobule VIII of cerebellar hemisphere. The MD values of the right middle temporal gyrus in the long-term abstinent group were negatively correlated with the number of completions within 60 seconds (r=-0.504) and within 120 seconds (r=-0.464) .
 Conclusion: The DTI parameters in multiple brain regions from the methamphetamine-dependence patients are still abnormal after a long-term abstinence. DTI can provide imaging evidence for brain microstructural abnormalities in long-term abstinent from methamphetamine-dependence.
Amphetamine-Related Disorders ; Anisotropy ; Brain ; Diffusion Tensor Imaging ; Humans ; Methamphetamine

OBJECTIVE: Working memory impairments serve as prognostic factors for patients with schizophrenia. Working memory deficits are mainly associated with gray matter (GM) thickness and volume. We investigated the association between GM diffusivity and working memory in controls and individuals with schizophrenia. METHODS: T1 and diffusion tensor images of the brain, working memory task (letter number sequencing) scores, and the demographic data of 90 individuals with schizophrenia and 97 controls were collected from the SchizConnect database. T1 images were parcellated into the 68 GM Regions of Interest (ROI). Axial Diffusivity (AD), Fractional Anisotropy (FA), Radial Diffusivity (RD), and Trace (TR) were calculated for each of the ROIs. RESULTS: Compared to the controls, schizophrenia group showed significantly increased AD, RD, and TR in specific regions on the frontal, temporal, and anterior cingulate area. Moreover, working memory was negatively correlated with AD, RD, and TR in the lateral orbitofrontal, superior temporal, inferior temporal, and rostral anterior cingulate area on left hemisphere in the individuals with schizophrenia. CONCLUSION: These results demonstrated GM microstructural abnormalities in the frontal, temporal, and anterior cingulate regions of individuals with schizophrenia. Furthermore, these regional GM microstructural abnormalities suggest a neuropathological basis for the working memory deficits observed clinically in individuals with schizophrenia.
Anisotropy ; Brain ; Diffusion ; Diffusion Tensor Imaging ; Gray Matter ; Gyrus Cinguli ; Humans ; Memory, Short-Term ; Schizophrenia

OBJECTIVE: The purpose of the present study was to clarify the relationship between white matter tracts and cognitive symptoms in children with high-functioning autism spectrum disorder (ASD). METHODS: We examined the cognitive functions of 17 children with high-functioning ASD and 18 typically developing (TD) controls and performed diffusion tensor imaging (DTI) tractography. We compared the results between the groups and investigated the correlations between the cognitive scores and DTI parameters within each group. RESULTS: The Comprehension scores in the ASD group exhibited a positive correlation with mean diffusivity (MD) in the forceps minor (F minor). In the TD group, the Comprehension scores were positively correlated with fractional anisotropy (FA) in the right inferior fronto-occipital fasciculus (IFO) and left anterior thalamic radiation (ATR), and negatively correlated with MD in the left ATR, radial diffusivity (RD) in the right IFO, and RD in the left ATR. Additionally, a positive correlation was observed between the Matching Numbers scores and MD in the left uncinate fasciculus and F minor, and RD in the F minor. Furthermore, the Sentence Questions scores exhibited a positive correlation with RD in the right inferior longitudinal fasciculus. Relative to TD controls, the specific tract showing a strong correlation with the cognitive scores was reduced in the ASD group. CONCLUSION: Our findings indicate that white matter tracts connecting specific brain areas may exhibit a weaker relationship with cognitive functions in children with ASD, resulting in less efficient cognitive pathways than those observed in TD children.
Anisotropy ; Autism Spectrum Disorder ; Autistic Disorder ; Brain ; Child ; Cognition ; Comprehension ; Diffusion Tensor Imaging ; Humans ; Neurobehavioral Manifestations ; Surgical Instruments ; White Matter