Treatment response of hippocampal neural plasticity in depression:a diffusion tensor imaging study

Cerebral small vessel disease (SVD) is a major health problem for its contribution to ≈45% of dementias, and about a fifth of all strokes worldwide, representing one of the most important causes of disabilities.1 The term SVD refers to a group of pathological processes with various etiologies that affect the small arteries, arterioles, venules, and capillaries of the brain. The most common forms are age- and hypertension-related SVD and cerebral amyloid angiopathy (CAA).2 Vessel wall changes may lead to both ischemic and hemorrhagic consequences: (1) a state of chronic hypoperfusion or vascular dysfunction responsible for incomplete infarction,3,4 (2) acute focal necrosis (lacunar infarct), or (3) vessel rupture manifesting as hemorrhagic SVD. The clinical consequences of SVD are various and mainly consist of cognitive, mood, and motor dysfunctions leading to functional disability in the late stages of the disease. Magnetic resonance imaging (MRI) has become crucial in the diagnosis of SVD enabling the evaluation of the disease progression both in the clinical and research settings. However, correlations between clinical features of SVD and conventional MRI measures have been partially discordant. Some authors suggested that the cumulative effect of SVD lesions, rather than the individual lesions themselves determines the clinical impact,5 whereas others suggested that the presence and severity of alterations nonvisible on conventional MRI might also be an explanation.6 In the past decade, diffusion tensor imaging (DTI) has been increasingly used for the evaluation of SVD patients because it is sensitive to tissue damage and can show abnormalities in both areas of white matter hyperintensities (WMH) and in normal appearing WM (NAWM). Despite the high sensitivity in detecting cerebral damage, DTI has a low specificity in detecting the underlying cause. In fact, we can only infer that DTI changes reflect a loss of WM …

Objective To discuss the value of magnetic resonance (MR) diffusion tensor imaging (DTI) technology in the diagnosis of the apparent diffusion coefficient (ADC) and the fraction anisotropy (FA) of neonates with hypoxic-ischemic encephalopathy (HIE) in the subacute stage. Methods Ten cases of normal full-term neonates and 34 term neonates diagnosed with HIE in the subacute stage were investigated with conventional MR and DTI.Of the 34 cases, 15 cases were mild HIE, 12 cases were moderate HIE, 7 cases were severe HIE.ADC/FA values in different parts of the brain were analyzed.And the receiver operating characteristic (ROC) curve was used, the sensitivity and specificity of the FA in specific parts were also analyzed. Results (1)On convention MRI: according to the MRI scoring system, score of mild group was(2.6±1.7) points, moderate group was (3.0±1.5) points, severe group was (5.8±1.3) points.There was significant difference between mild group and severe group, moderate and severe group(P 0.05). FA values in posterior limb of internal capsule (PLIC), splenium had statistic difference between the HIE group and the controls.FA values in mild group were (0.317±0.018, 0.339±0.025), moderate group (0.295±0.025, 0.324±0.026) and severe group (0.252±0.039, 0.253±0.036) and control group (0.455±0.047, 0.372±0.032). (3) ROC analysis of the neonates diagnosed with HIE: the area under the ROC curve of FA values in PLIC, Splenium had statistic difference between mild group and moderate group (P<0.05). The area under the ROC curve in each group was 0.744(P=0.032), 0.658 (P=0.164). ROC curve was used to evaluate the diagnostic accuracy of FA values in PLIC between HIE group and control group, when FA value was lower than 0.337, 0.803 was the largest area under the ROC curve, and there was significant difference between them(P<0.01). Conclusions FA values can reflect the brain white matter WM injury of HIE neonates quantitatively, and its diagnostic veracity is better than ADC value and conventional MR during the subacute phase of HIE.The diagnostic veracity of FA values in PLIC is higher than other parts.When the FA value is lower than 0.337, there is good sensitivity and specificity in diagnosis of HIE, so DTI technology can provide accurate and objective basis for clinical treatment with good sensitivity and specificity about the diagnosis of HIE in early stage. Key words: Infant, newborn; Hypoxic-ischemic encephalopathy; Diffusion tensor imaging; Fraction anisotropy

Currently there is little report about the application of diffusion tensor imaging (DTI) technology to judge the prognosis of patients with cerebral apoplexy. This study was to investigate cerebral functional connection in both sides of the M1 area in patients with cerebral infarction, who were treated with transcranial magnetic stimulation (TMS), using DTI technology. Fifteen patients with cerebral infarction admitted to the hospital between February 2013 and August 2014 were enrolled for the study. The patients were treated with TMS and underwent DTI. The fractional anisotropy (FA), apparent diffusion coefficient (ADC), the relative FA value (rFA), and relative ADC values (rADC) were analyzed using paired t-test. rFA, rADC, and NIHSS of the lesion side before and after treatment were analyzed by Spearman correlation analysis. The results showed that before treatment, ADC value and FA value of the lesion side were lower than those of the contralateral healthy side with statistical significance (ADCt = 2.849, P < 0.05; FAt = 10.285, P < 0.05). Four weeks after treatment, ADC value and FA value of the lesion side were higher than those before treatment with statistical significance (ADCt = 6.206, P < 0.05; FAt = 3.788, P < 0.05). Both rFA values of pre-treatment and post-treatment showed negative correlation with NIHSS score with statistical significance (P < 0.05). In conclusion, after TMS with TDI technique, the value of FA and ADC values significantly increased compared to that of pre-treatment. It suggested that transcranial magnetic stimulation played a positive role in stroke rehabilitation.

A study of diffusion tensor imaging by tissue-specific, smoothing-compensated voxel-based analysis

Major depressive disorder and white matter abnormalities: A diffusion tensor imaging study with tract-based spatial statistics

Diffusion tensor imaging (DTI) has demonstrated its utility in detecting microscopic post-concussion cerebral white matter structural changes, which are not routinely evident on conventional neuroimaging modalities. In this study, we compared 10 adolescents with sports concussion (SC) to 12 orthopedically-injured (OI) individuals within 96h and three months post injury to 12 typically-developing (TD) participants using DTI and volumetric analyses. In terms of volume, no group differences were noted between SC, OI and TD groups at both 96h and three months post concussion. Results did not show significant differences between SC, OI, and TD groups for both fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in all regions of interest within 96h post concussion. However, at three months post-injury, the SC group exhibited significantly lower FA than the TD group in various regions of interest. In terms of ADC, significant group differences between SC and TD groups were found in some regions, with SC group having higher ADC than TD. No group differences for FA and ADC were noted between SC and OI groups at three months post-injury. However, several moderate effect sizes on between-group analyses were noted such that FA was lower and ADC was higher in SC relative to OI. Longitudinally, the SC group demonstrated decreased FA and increased ADC in some areas. The findings highlight the fact that the brain continues to change during the post-injury recovery period, and raises the possibility that adverse changes may result from the neurometabolic cascade that purportedly ensues following SC. DTI may potentially be used to characterize the nature of brain changes that occur following sports-related concussions.

Mild cognitive impairment (MCI) is a heterogeneous cognitive disorder that is often comorbid with Parkinson’s diseases (PD). The amnestic subtype of PD-MCI (PD-aMCI) has a higher risk to develop dementia. However, there is a lack of studies on the white matter (WM) structural changes of PD-aMCI. We characterized the WM structural changes of PD-aMCI (n = 17) with cognitively normal PD (PD-CN, n = 19) and normal controls (n = 20), using voxel-based and tract-based spatial statistics (TBSS) analyses on fractional anisotropy (FA) axial diffusivity (AD), and radial diffusivity (RD). By excluding and then including the motor performance as a covariate in the comparison analysis between PD-aMCI and PD-CN, we attempted to discern the influences of two neuropathological mechanisms on the WM structural changes of PD-aMCI. The correlation analyses between memory and voxel-based WM measures in all PD patients were also performed (n = 36). The results showed that PD-aMCI had smaller FA values than PD-CN in the diffuse WM areas, and PD-CN had higher AD and RD values than normal controls in the right caudate. Most FA difference between PD-aMCI and PD-CN could be weakened by the motor adjustment. The FA differences between PD-aMCI and PD-CN were largely spatially overlapped with the memory-correlated FA values. Our findings demonstrated that the WM structural differences between PD-aMCI and PD-CN were mainly memory-related, and the influence of motor adjustment might indicate a common mechanism underlying both motor and memory impairment in PD-aMCI, possibly reflecting a predominant influence of dopaminergic neuropathology.

Magnetization transfer measurements of cerebral white matter in patients with myotonic dystrophy

This study used fractional anisotropy (FA), a measure of diffusion tensor imaging, to analyze white matter abnormalities in 15 first-episode treatment-naïve patients with major depressive disorder (MDD) and 15 controls matched for age. An automated voxel-based analysis and a region-of-interest (ROI) method with 3T magnetic resonance imaging were used. Compared with controls, FA values were lower in the left superior longitudinal fasciculus, the left prefrontal cortex, and the left parietal region in patients with MDD. In addition, the ROI method revealed significantly lower FA values in the right hippocampus. Voxel-based analysis, a faster technique, complements the ROI method, which highlights FA values as potential biomarkers in early MDD.

Anti-basal ganglia antibodies (ABGAs) have been suggested to be a hallmark of autoimmunity in Gilles de la Tourette’s syndrome (GTS), possibly related to prior exposure to streptococcal infection. In order...

Objective To investigate the white matter microstructural changes of cingulation and congni-tive function impairment in patient with major depression. Methods 25 middle-aged first episode patients and 24 nondepressed comparison participants were enrolled,and all the subjects scanned by diffusion tensor imaging and tested by Wisconsin Card Sorting Test. Correlation analysis was done respectively for both two groups with FA and WCST items. Results Male patients with depression decreased FA in the middle frontal lobe ( - 29 24 32,16 voxels),the left superior temporal lobe (-36 -34 16,11 voxels),the sub-gyral of temporal lobe ( -45 1 - 15/ - 47 - 6 - 9; 16/10 voxels) and the right lobe of cingulate (18 - 2 29,22 voxels). And the female patients with depression shows reduced FA in the inferior frontal lobe ( -42 23 4/45 24 6; 15/21 voxels) ,the left precentral gy-rus (39 -44 -15,17 voxels) ,the right medial frontal gyrus (6 16 -18; 10 voxels) ,the left superior temporal lobe ( -55 -31 15; 89 voxels) ,the sub-gyral of temporal lobe ( -38 - 12 - 19;12 voxels) and the right anterior cingulate gyrus (71 26 -9; 15 voxels) (P 10 voxels). The Regions of interests analyze with cingulate only found reduced FA in the right lobe of female group(0.26 ±0.05,0.33 ±0.08; P=0.03). Correlation were found between the right anterior cingulate and Rpe (r= -0.49, P = 0. 03) ,the right middle cingulate and Rpe (r= -0.56, P = 0. 01) in depressed patients. No significant association were found in healthy control group(P> 0.05). Conclusion Cingulate white matter fiber is abnormal in first episode depression and these abnormalities may be one of the pathophysiology of major depression. Key words: Depression; Cingulate; Executive function; Diffusion Tensor Imaging

Aims/IntroductionOlder adults with diabetes mellitus are susceptible to sarcopenia. Diffusion tensor imaging studies have also shown that patients with diabetes have altered white matter integrity. However, the relationship between these structural changes in white matter and sarcopenia remains poorly understood.Materials and MethodsThe study included 284 older patients (aged ≥65 years) who visited the Tokyo Metropolitan Geriatric Hospital Frailty Clinic. We used diffusion tensor imaging to measure fractional anisotropy (FA) and mean diffusivity (MD) to evaluate changes in white matter integrity. We investigated the associations between sarcopenia, or its diagnostic components, and FA or MD in seven white matter tracts considered to be associated with sarcopenia according to the patients’ diabetes status.ResultsWe found significantly low FA or high MD values in the bilateral anterior thalamic radiations (ATR) and right inferior fronto‐occipital fasciculus (IFOF) of patients with Asian Working Group for Sarcopenia 2019‐defined sarcopenia, in all patients and those with diabetes. Using binominal regression analyses, we associated low FA values in the left ATR and right IFOF with sarcopenia in all patients and those with diabetes, after adjusting for age, gender, HbA1c, blood pressure, cognitive function, physical activity, depression, nutritional status, and inflammation.ConclusionsWhite matter alterations in left ATR and right IFOF are associated with the prevalence of sarcopenia in patients with diabetes. Specific changes to the left ATR and right IFOF tracts could play critical roles in the occurrence of sarcopenia in patients with diabetes.

This review seeks to summarize diffusion tensor imaging (DTI) studies that have evaluated structural changes attributed to the mechanisms of mild traumatic brain injury (mTBI) in adult civilian, military, and athlete populations. Articles from 2002 to 2016 were retrieved from PubMed/MEDLINE, EBSCOhost, and Google Scholar, using a Boolean search string containing the following terms: "diffusion tensor imaging", "diffusion imaging", "DTI", "white matter", "concussion", "mild traumatic brain injury", "mTBI", "traumatic brain injury", and "TBI". We added studies not identified by this method that were found via manually-searched reference lists. We identified 86 eligible studies from English-language journals using, adult, human samples. Studies were evaluated based on duration between injury and DTI assessment, categorized as acute, subacute/chronic, remote mTBI, and repetitive brain trauma considerations. Since changes in brain structure after mTBI can also be affected by other co-occurring medical and demographic factors, we also briefly review DTI studies that have addressed socioeconomic status factors (SES), major depressive disorder (MDD), and attention-deficit hyperactivity disorder (ADHD). The review describes population-specific risks and the complications of clinical versus pathophysiological outcomes of mTBI. We had anticipated that the distinct population groups (civilian, military, and athlete) would require separate consideration, and various aspects of the study characteristics supported this. In general, study results suggested widespread but inconsistent differences in white matter diffusion metrics (primarily fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) following mTBI/concussion. Inspection of study designs and results revealed potential explanations for discrepant DTI findings, such as control group variability, analytic techniques, the manner in which regional differences were reported, and the presence or absence of persistent functional disturbances. DTI research in adult mTBI would benefit from more standardized imaging and analytic approaches. We also found significant overlap in white matter abnormalities reported in mTBI with those commonly affected by SES or the presence of MDD and ADHD. We conclude that DTI is sensitive to a wide range of group differences in diffusion metrics, but that it currently lacks the specificity necessary for meaningful clinical application. Properly controlled longitudinal studies with consistent and standardized functional outcomes are needed before establishing the utility of DTI in the clinical management of mTBI and concussion.

Association of brain-derived neurotrophic factor DNA methylation and reduced white matter integrity in the anterior corona radiata in major depression

Objective Using diffusion tensor imaging (DTI) to explore the microstructure changes of white matter in subcortical ischemic vascular cognitive impairment (SIVCI) and its correlation with cognitive function. Methods Forty-nine patients with subcortical ischemic cerebrovascular diseases were collected. By using Clinical Dementia Rating Scale (CDR), they were classified into 10 cases of vascular dementia (VaD group), 20 cases of vascular cognitive impairment-no dementia (VCIND group) and 19 cases of normal cognitive function (control group). Conventional MRI and DTI were performed in all cases. Based on the DTI data, voxel-based analysis was used to assess the whole brain region. Correlation analysis was applied to illustrate the relationship between DTI parameters and cognitive scale in VaD patients. Results Compared with the control group, fractional anisotropy (FA) values of patients in VaD group decreased in medial prefrontal cortex, anterior cingulate cortex, corpus callosum stem, bilateral parietal lobes, right temporal lobe and bilateral orbitofrontal lobes ( P = 0.000, for all), and FA values of patients in VCIND group decreased in right inferior frontal gyrus, right hippocampus and bilateral precuneus ( P = 0.000, for all). Compared with VCIND group, FA values of patients in VaD group decreased in medial prefrontal cortex, anterior cingulate, corpus callosum, bilateral parietal lobes and right temporal lobe ( P = 0.000, for all). Compared with the control group, mean diffusivity (MD) values in VaD group increased in medial prefrontal cortex, corpus callosum, bilateral parietal lobes, bilateral temporal lobes and anterior cingulate ( P = 0.000, for all), while in VCIND group increased in bilateral precuneus and right hippocampus ( P = 0.000, for all). Compared with VCIND group, MD values in VaD group increased in right medial prefrontal cortex, anterior cingulate cortex, corpus callosum stem, bilateral parietal lobes and bilateral temporal lobes ( P = 0.000, for all). The correlation analysis showed that the FA value of medial prefrontal lobe in VaD group was negatively correlated with the time to finish Trail Making Test A (TMT-A; r = - 0.782, P = 0.007), and MD value of bilateral inferior frontal gyrus was positively correlated with the time to complete TMT-A ( r = 0.877, P = 0.001). Conclusions DTI was more sensitive on the white matter microstructure change of SIVCI patients than conventional MRI. It can reflect patient's early cognitive functional changes. Microstructrual change in medial prefrontal white matter is an important factor which may influence the executive functions of patients with SIVCI. doi: 10.3969/j.issn.1672-6731.2014.04.009