Diffusion tensor imaging study of white matter fiber in patients with schizophrenia episode in early adulthood / 新乡医学院学报

Objective To explore the structure changes of white matter of the patients with schizophrenia episode in early adulthood by diffusion tensor imaging(DTI) and in order to provide a structural neuroimaging basis for understanding the pathology of schizophrenia.Methods Twenty-six patients with schizophrenia episode in early adulthood in the Second Affiliated Hospital of Xinxiang Medical University from July 2012 to March 2014 were selected as study group and twenty-eight healthy subjects whose age,sex,education were matched with study group were selected as control group.All subjects received structural magnetic resonance imaging and DTI scans.The fractional anisotropy (FA) and the mean diffusivity (MD) of the white matter of the same encephalic region were compared between the two groups by voxel-based analyses.Results The FA values of the right anterior cingulate gyrusthe,genu of corpus callosum,the right limb of internal capsule,the bilateral external capsule,the bilateral posterior of coronal radiate,the right anterior coronal radiate of patients in the study group were significantly lower than those in the control group (P ＜ 0.05).The MD values of the bilateral limbs of internal capsule,the right cingulate gyrus,left superior longitudinal tract,corpus callosum and right anterior coronal radiate of patients in the study group were significantly higher than those in the control group (P ＜ 0.05).Conclusion Schizophrenia patients who episode in early adulthood exist widespread microstructural damage of white matter.These changes may be related to the pathological change of schizophrenia.

Characterization of the brain gray matter in amnestic mild cognitive impairmentby diffusion tensor imaging / 医学研究生学报

Objective Amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD)used to be evaluated by an-alyzing the characteristics of the brain gray matter via diffuse tensor imaging (DTI).This study was to characterize the damage to the mi-crostructural integrity of the brain gray matter in aMCI and AD patients using the mean diffusivity ( MD) of DTI and to investigateits transformation rules. Methods This retrospective study included 30 cases ofaMCI, 30 cases of AD, and another 30 normal controls. We measured the MD values of the whole brain gray matter , established the MD network of the water molecules in the gray matter , char-acterized the small-world network, and performed correlation analysis by neuropsychological assessment . Results Compared with the normal controls, the MDnetworks of the aMCI and AD groupsexhibited abnormal small world characteristics , namely, a higher clustering coefficient and a longer path , which reflected the damage to themicrostructure of the gray matter , and theaverage connectivity in the aMCI patients was lowerthan that in thenormal controls but higher than that in the AD group ( P<0.05) .The MD values of the gray matter were negatively correlated with the Montreal Cognitive Assessment Scale scores in the 11 hub regions of the brain , including the bilateral hippo-campus and the limbic system ( P<0.05) . Conclusion The diffusion feature of the water molecules in the brain gray matter of the aMCIpatient may help to detect early ADand reflect the damage to the brain microstructure in patients with neurodegenerative diseases .

Accuracy of Diffusion Tensor Imaging for Diagnosing Cervical Spondylotic Myelopathy in Patients Showing Spinal Cord Compression

OBJECTIVE: To assess the performance of diffusion tensor imaging (DTI) for the diagnosis of cervical spondylotic myelopathy (CSM) in patients with deformed spinal cord but otherwise unremarkable conventional magnetic resonance imaging (MRI) findings. MATERIALS AND METHODS: A total of 33 patients who underwent MRI of the cervical spine including DTI using two-dimensional single-shot interleaved multi-section inner volume diffusion-weighted echo-planar imaging and whose spinal cords were deformed but showed no signal changes on conventional MRI were the subjects of this study. Mean diffusivity (MD), longitudinal diffusivity (LD), radial diffusivity (RD), and fractional anisotropy (FA) were measured at the most stenotic level. The calculated performance of MD, FA, MD∩FA (considered positive when both the MD and FA results were positive), LD∩FA (considered positive when both the LD and FA results were positive), and RD∩FA (considered positive when both the RD and FA results were positive) in diagnosing CSM were compared with each other based on the estimated cut-off values of MD, LD, RD, and FA from receiver operating characteristic curve analysis with the clinical diagnosis of CSM from medical records as the reference standard. RESULTS: The MD, LD, and RD cut-off values were 1.079 × 10⁻³, 1.719 × 10⁻³, and 0.749 × 10⁻³ mm²/sec, respectively, and that of FA was 0.475. Sensitivity, specificity, positive predictive value and negative predictive value were: 100 (4/4), 44.8 (13/29), 20 (4/20), and 100 (13/13) for MD; 100 (4/4), 27.6 (8/29), 16 (4/25), and 100 (8/8) for FA; 100 (4/4), 58.6 (17/29), 25 (4/16), and 100 (17/17) for MD∩FA; 100 (4/4), 68.9 (20/29), 30.8 (4/13), and 100 (20/20) for LD∩FA; and 75 (3/4), 68.9 (20/29), 25 (3/12), and 95.2 (20/21) for RD∩FA in percentage value. Diagnostic performance comparisons revealed significant differences only in specificity between FA and MD∩FA (p = 0.003), FA and LD∩FA (p < 0.001), FA and RD∩FA (p < 0.001), MD and LD∩FA (p = 0.024) and MD and RD∩FA (p = 0.024). CONCLUSION: Fractional anisotropy combined with MD, RD, or LD is expected to be more useful than FA and MD for diagnosing CSM in patients who show deformed spinal cords without signal changes on MRI.

Abnormal Integrity of Corticocortical Tracts in Mild Cognitive Impairment: A Diffusion Tensor Imaging Study

Mild cognitive impairment (MCI) has been defined as a transitional state between normal aging and Alzheimer disease. Diffusion tensor imaging (DTI) can estimate the microstructural integrity of white matter tracts in MCI. We evaluated the microstructural changes in the white matter of MCI patients with DTI. We recruited 11 patients with MCI who met the working criteria of MCI and 11 elderly normal controls. The mean diffusivity (MD) and fractional anisotropy (FA) were measured in 26 regions of the brain with the regions of interest (ROIs) method. In the MCI patients, FA values were significantly decreased in the hippocampus, the posterior limb of the internal capsule, the splenium of corpus callosum, and in the superior and inferior longitudinal fasciculus compared to the control group. MD values were significantly increased in the hippocampus, the anterior and posterior limbs of the internal capsules, the splenium of the corpus callosum, the right frontal lobe, and in the superior and the inferior longitudinal fasciculus. Microstructural changes of several corticocortical tracts associated with cognition were identified in patients with MCI. FA and MD values of DTI may be used as novel biomarkers for the evaluation of neurodegenerative disorders.

MR Diffusion Tensor Imaging in Optic Atrophy / 实用放射学杂志

Objective To study the MR diffusion tensor imaging(MR-DTI) feature of optic atrophy.Methods Diffusion tensor imaging data of optic nerve were acquired in twenty patients with optic atrophy and 20 healthy subjects.Results ①Atrophic optic nerves were thin obviously on MRI,and the signal of atrophic optic nerves decreased markedly on fractional anisotropy(FA) map and directionally encoded color(DEC) map.②The FA value(0.277?0.078) and ?∥ value(1.808?0.307) of atrophic optic nerves were declined obviously,and mean diffusivity(MD) value(1.442?0.264) and ?⊥ value(1.231?0.225) increased obviously in comparison to the normal optic nerves,there were statistically significant differences between the patients and the volunteers(P