Application of diffusion tensor imaging scanning of conus medullaris in lower urinary tract dysfunction / 中国康复理论与实践

Objective To investigate the signal abnormality of conus medullaris in patients with overactive bladder(OAB)and un-deractive bladder(UAB)by MRI diffusion tensor imaging(DTI). Methods From May,2021 to April,2023,23 patients with lower urinary tract dysfunction without trauma and supraspi-nal lesions were enrolled(case group).All patients underwent imaging urodynamics and pelvic floor electromy-ography.Based on the bladder contraction during the filling phase of urodynamics,the patients were divided into UAB group and OAB group.Eight healthy subjects were included as the control group.All participants under-went T10 to L5 spinal segment MRI scans and DTI scans.The position of conus medullaris was determined by comparing the DTI sequences with the MRI scans.The fractional anisotropy(FA),apparent diffusion coefficient(ADC),and relative anisotropy(RA)of the conus medullaris intermediate segment were compared. Results Twelve cases were in UAB group,and eleven in OAB goup.Abnormalities were found in the pelvic floor elec-tromyography in the case group.There was significant difference in sacral reflex arc nerve conduction testing be-tween UAB and OAB groups(P = 0.036).Compared with the control group,ADC increased(t = 2.185,P = 0.037)in the case group;FA decreased(t = 3.439,P = 0.005)and ADC increased(t = 4.582,P<0.001)in UAB group. Conclusion DTI is helpful to find the potential lesion of spinal cord in patients with lower urinary tract dysfunction.FA and ADC are valuable indicators for the diagnosis of conus medullaris injury.

Application and progress of cardiac magnetic resonance quantitative technology in the evaluation of myocardial lesions / 中国医师杂志

Cardiovascular disease is the leading cause of death among Chinese residents, and non-invasive imaging technology has important value in the diagnosis and treatment of cardiovascular disease. Cardiac magnetic resonance (CMR) can characterize cardiac pathophysiological information from multiple dimensions, including cardiac structure, function, tissue characteristics, and microstructure, through multi parameter and multi sequence " one-stop" imaging. This article will focus on new technologies such as CMRT1 mapping, feature tracking, and diffusion tensor imaging, and explain their applications and progress in the diagnosis, efficacy monitoring, and prognosis prediction of various myocardial lesions such as non ischemic heart disease and ischemic heart disease.

Diagnosis of Diffusion Tensor Imaging in Poststroke Depression / 中国医学影像学杂志

Purpose To explore the changes of structure of cerebellum,frontal lobe and limbic system(cingulate gyrus,hippocampus and amygdala)in poststroke depression(PSD)via diffusion tensor imaging,and to confirm that cerebellum was involved in the occurrence of PSD,and to study the correlation between cerebellum and traditional depression-related areas such as frontal lobe,limbic system(cingulate gyrus,hippocampus and amygdala).Materials and Methods A total of 39 patients with basal ganglia infarction for the first time from October 2020 to October 2021 in the First Affiliated Hospital of Jinzhou Medical University were evaluated by Hamilton depression scale(HAMD),and all subjects were divided into PSD group(19 cases)and non-PSD group(20 cases),and 20 people with no statistical difference in basic information were randomly selected as the normal control group.The fractional anisotropy(FA)values and apparent diffusion coefficient in region of interest via diffusion tensor imaging were measured.The FA values of lesion and contralateral region of interest were compared among the three groups,and the correlation between FA value and HAMD score was analyzed.Results The FA values of ROI in the prefrontal lobe,hippocampus,cingulate gyrus,corpus callosum,middle cerebellar peduncle,and inferior cerebellar crus in the PSD group were significantly different from those in the non-PSD group and normal control group(t=-0.12--0.06,all P<0.05).The FA values of cerebellum,frontal lobe and limbic system were significantly negatively correlated with HAMD scores(R2adjust=0.954,P<0.05).There was a positive correlation between the FA value of contralateral foot in the cerebellum of PSD patients and that of prefrontal lobe,hippocampus,cingulate gyrus and knee of corpus callosum(r=0.977,0.752,0.637 and 0.539,all P<0.05),respectively.Conclusion PSD patients may have changes in the white matter fiber tracts of the cerebellum,which are associated with traditional depressions.

Study of cognitive functional changes in children with spastic cerebral palsy using diffusion tensor imaging based graph theory analysis / 中华放射学杂志

Objective:To explore brain network properties and their relationship with cognitive function in children with spastic cerebral palsy (SCP) using diffusion tensor imaging (DTI) based graph theory analysis.Methods:The study was a cross-sectional study. Clinical and imaging data of 21 children with SCP (SCP group) and 32 healthy children (control group) who underwent cranial MRI at the Affiliated Hospital of Zunyi Medical University from August 2020 to April 2022 were analyzed retrospectively. 3D-T 1WI, DTI and Wechsler Intelligence Scale were assessed for all subjects. The Wechsler Intelligence Scale included the verbal comprehension index (VCI), the processing speed index (PSI), the work memory index (WMI), and the perceptual reasoning index (PRI), etc., and ultimately the full scale intelligence quotient (FSIQ) scores were obtained based on the indices of each subscale. Independent samples t-test was used to analyze the differences in the small world attributes [small-world index (σ), normalized shortest path length (λ), normalized clustering coefficients (γ)], global attributes [global efficiency (Eglob), local efficiency (Eloc), characteristic path length (Lp), clustering efficiency (Cp)] and node attributes [degree centrality(DC), nodal efficiency (Ne), betweeness centrality (Bc), nodal shortest path length (NLp), nodal clustering efficiency, nodal local efficiency] between two groups of children′s brain networks. Brain network indicators with statistically significant differences between the 2 groups were correlated with Wechsler Intelligence Scale scores using Spearman. Results:The FSIQ scores on the Wechsler Intelligence Scale and the VCI, WMI, PSI, and PRI were lower in the SCP group than in the control group, and the differences were all statistically significant (all P<0.05). Both groups of children′s brain networks had small world properties. Compared with the control group, Eglob decreased, Lp and λ increased in the SCP group (all P<0.05). Compared with the control group, DC and Ne in multiple brain regions decreased, NLp increased in the SCP group (all P<0.05, FDR corrected). Correlation analysis showed that DC in the right parsopercularis was positively correlated with FSIQ, VCI, WMI and PRI( r=0.53, 0.47, 0.47, 0.60, P=0.019, 0.045, 0.044, 0.020, respectively); NLp in the right parsopercularis was negatively correlated with PRI( r=-0.56, P=0.030); Ne in left paracentral, the right parsopercularis, right precentral, right postcentra were positively correlated with PRI( r=0.62, 0.56, 0.53, 0.54, P=0.015, 0.031, 0.044, 0.039, respectively); Ne in the right precentral was positively correlated with WMI ( r=0.48, P=0.039) in the SCP group. Conclusions:There are changes in the topological attributes of global and multiple regional brain networks in SCP. The changes in the attributes of nodes in the right parsopercularis, right precentral, right postcentral, and left paracentral could reflect cognitive dysfunction in children with SCP.

Research advances on the applications of functional magnetic resonance imaging for evaluating kidney transplant function / 中华器官移植杂志

After kidney transplantation , timely detection of changes in transplanted kidney function may guide clinical managements and prevent or delay irreversible damage to transplanted kidney. Functional magnetic resonance imaging (fMRI) of transplanted kidney is a promising non-invasive technique of acquiring microstructural and microfunctional profiles of transplanted kidney. In recent years, various diffusion imaging modalities, arterial spin labeling (ASL) and blood oxygen level dependent-magnetic resonance imaging (BOLD-MRI) have gradually been applied for transplant kidneys. Transplant kidney function may be evaluated non-invasively from such microscopic perspectives as water molecule diffusion, blood flow perfusion and blood oxygen level. This review focused upon evaluating the renal function and identifying the causes of the renal function decline of transplanted kidney through various fMRI techniques and provide new rationales for clinical diagnosis.

Prediction of isocitrate dehydrogenase status of glioma via diffusion tensor imaging parameters and clinical features / 实用放射学杂志

Objective To noninvasively predict isocitrate dehydrogenase(IDH)status of glioma via combining imaging and clini-cal features before surgery,so as to provide basis for individualized clinical treatment decision.Methods A total of 47 patients with glioma confirmed by pathological and molecular genetic tests were included,including 20 with IDH mutant type and 27 with IDH wild type.After diffusion tensor imaging(DTI)scanning,fractional anisotropy(FA)and mean diffusivity(MD)values of tumor paren-chyma were calculated.Combining DTI parameters with MRI morphological features of tumor,blood neutrophil/lymphocyte ratio(NLR)and patient's age,binary logistic regression model was established to effectively predict IDH status of glioma patients before surgery.Results There were significant differences in FAmean/FANAWM,MDmin,NLR,tumor location and age between IDH mutant type and IDH wild type groups(P<0.05).The binary logistic regression model concluding,FAmean/FANAWM,MDmin,cystic degeneration,NLR and age,predicted IDH status of glioma with area under the curve(AUC)of 0.961 and 95%confidence interval(CI)of 0.914-1.00.Conclusion The regression model established via combining DTI,MRI morphological features and blood NLR has great performance in classifying IDH status of glioma,and can help predict IDH status noninvasively before surgery,so as to assist clinical individualized treatment.

Effect of virtual reality on upper limb function after stroke: a study of diffusion tensor imaging / 中国康复理论与实践

ObjectiveTo explore the effect of virtual reality on upper limb function in stroke patients through diffusion tensor imaging (DTI). MethodsFrom September, 2021 to March, 2023, 80 stroke patients in the Fuzhou Second General Hospital were randomly divided into control group (n = 40) and experimental group (n = 40). Both groups received routine rehabilitation, while the experimental group received virtual reality training additionally, for four weeks. They were assessed with Fugl-Meyer Assessment-Upper Extremities (FMA-UE) and Action Research Arm Test (ARAT) before treatment, after treatment and after four-week follow-up; and they were scaned with DTI to measure the fractional anisotropy (FA) and relative anisotropy (RA) of cerebral peduncle and posterior limb of inner capsule of the affected side before and after treatment. ResultsTwo cases dropped in each group. The FMA-UE and ARAT scores increased in both groups after treatment and follow-up (F > 2.790, P < 0.001), and increased more in the experimental group than in the control group (t > 2.297, P < 0.05). FA and RA in the posterior limb of inner capsule increased in both groups after treatment (t > 21.013, P < 0.001), and increased more in the experimental group (t > 2.006, P < 0.05). The d-value of FA of the posterior limb of internal capsule before and after treatment (ΔFA) was positively correlated with the d-value of FMA-UE score (r > 0.362, P < 0.05) in both groups, the ΔFA of the posterior limb of internal capsule was positively correlated with the d-value of ARAT score (r = 0.459, P < 0.01). ConclusionVirtual reality training can promote the recovery of upper limb function in stroke patients, which may associate with the conductivity of posterior limb of inner capsule.

Evaluation value of magnetic resonance diffusion tensor imaging for cerebrovascular small vessel disease in patients with systemic lupus erythematosus / 中国医师进修杂志

Objective:To explore the value of magnetic resonance diffusion tensor imaging (DTI) in evaluating cerebrovascular small vessel disease (CSVD) in patients with systemic lupus erythematosus (SLE).Methods:Eighty-two patients with SLE combined with CSVD treated at Yixing People's Hospital from January to December 2022 were selected. They were divided into acute phase infarction group (16 cases), chronic phase infarction group (26 cases), and chronic ischemic lesion group (40 cases) based on routine MRI examination results. All patients underwent DTI examination to obtain the average diffusion coefficient (DCavg) and anisotropy score (FA) of the affected and contralateral normal white matter areas, and the evaluation value of DTI for CSVD in SLE patients was analyzed.Results:The DCavg value on the affected side of 82 patients was significantly higher than that on the healthy side: (11.10 ± 3.48) 10 -3 mm 2/s vs. (8.18 ± 2.42) 10 -3 mm 2/s, and the FA value on the affected side was significantly lower than that on the healthy side: 0.28 ± 0.05 vs. 0.45 ± 0.08, with a statistical significant differences ( P<0.05). The DCavg values of the acute infarction group, chronic infarction group, and chronic ischemic focus group were (11.88 ± 3.50), (9.69 ± 3.24) and (8.52 ± 2.34) 10 -3 mm 2/s, respectively, with statistical significant differences ( P<0.05). The FA values of the acute infarction group, chronic infarction group, and chronic ischemic focus group were 0.28 ± 0.04, 0.33 ± 0.06 and 0.40 ± 0.07, respectively, with statistical significant differences ( P<0.05). The receiver operating characteristic curve was drawn, and the results showed that the area under the curve (AUC) of the acute phase infarction group and the chronic phase infarction group evaluated by DCavg and FA alone and in combination were 0.757, 0.756, and 0.820, respectively. The AUC of the chronic phase infarction group and the chronic ischemic focus group evaluated by DCavg and FA were 0.772, 0.776, and 0.813, respectively. The AUC value of the combined evaluation was relatively large. Conclusions:DTI has good evaluation value for CSVD in SLE patients and can accurately determine the type of CSVD.

Application of DSI Studio Software Combined with DTI in Motor Function Evaluation of Postoperative Brain Functional Area Tumor / 医学研究杂志

Objective To study the value of DSI Studio combined with diffusion tensor imaging(DTI)in evaluating the prognosis of postoperative motor function in patients with brain functional area tumors.Methods From January 2018 to August 2022,41 patients with brain functional area tumors who underwent surgical treatment and were pathologically diagnosed in our hospital were included in the study.All patients completed 3.0 T MRI routine sequence and DTI examination.DTI parameters of the corticospinal tract(CST)projection area of posterior limb of the internal capsule on the affected side and the healthy side were measured respectively,and the correlation with MRC muscle strength score and the CST grade was analyzed.Results The FA value of the affected side was significantly lower than that of the healthy side(P＜0.001),and the ADC value of the affected side was significantly higher than that of the healthy side(P＜0.001).The FA value of the affected side and the lateral rFA value were negatively correlated with the CST grade(P＜0.01).ADC value and rADC value were positively correlated with CST grade(P＜0.01).The FA value of the affected side and the partial rFA value were positively correlated with the degree of muscle strength score before and after surgery(P＜0.01).ADC value and rADC value were negatively corre-lated with CST grade(P＜0.01).Preoperative CST grading was negatively correlated with contralateral muscle strength.The area under the ROC curve of FA value,rFA value,ADC value,rADC value,and CST grade were 0.820(P＜0.01),0.796(P＜0.01),0.698(P＜0.05),0.638(P＞0.05)and 0.708(P＜0.05),respectively.Conclusion DTI parameters,muscle strength score and CST grade have certain value in the evaluation of postoperative motor function prognosis in patients with brain functional tumors.

Técnicas de Neuroimagenología en la Cuantificación de la Neuroplasticidad en Pacientes con Enfermedad Vascular Cerebral / Neuroimaging Techniques for Neuroplasticity Quantification in Stroke Patients

RESUMEN Las técnicas de neuroimagenología otorgan información relevante del estado funcional y anatómico del cerebro humano. Esta información es particularmente importante cuando existe una lesión cerebral causada por alguna patología, tal como la enfermedad vascular cerebral (EVC). En pacientes afectados por esta enfermedad, se ha determinado que la neuroplasticidad es el mecanismo principal de recuperación de la función motora perdida. Debido a la alta prevalencia de la EVC a nivel mundial y especialmente en países en vías de desarrollo, es necesario continuar investigando los mecanismos de recuperación involucrados en esta patología. La resonancia magnética funcional (RMF) y la imagenología por tensor de difusión (ITD) son dos de las técnicas de neuroimagenología más utilizadas con este fin. La RMF permite analizar la actividad neuronal generada al ejecutar tareas de movimiento, mientras que la ITD proporciona información estructural de la anatomía cerebral. En esta revisión narrativa, se presentan diversos estudios que han utilizado estas técnicas de neuroimagenología en la cuantificación de los cambios de neuroplasticidad en pacientes con EVC tras participar en algún programa de neurorrehabilitación. Comprender mejor estos cambios de neuroplasticidad permitiría diseñar esquemas de rehabilitación que proporcionen un mayor beneficio a los pacientes con EVC.

ABSTRACT Neuroimaging techniques provide relevant information of the functional and anatomical status of the human brain. This information is of particular importance when a pathology, like stroke, produces a brain injury. In stroke patients, it has been determined that neuroplasticity is the primary recovery mechanism of the lost motor function. Due to worldwide high prevalence, especially in developing countries, it is necessary to continue the research of the recovery mechanisms involved in this pathology. To this end, functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) are two of the most used neuroimaging techniques. In stroke patients, fMRI allows the analysis of the neural activity produced by the execution of motor tasks, whereas DTI provides structural information of the brain anatomy. In this narrative review, multiple studies that employ these neuroimaging techniques for quantification of neuroplasticity changes in stroke patients after undergoing a neurorehabilitation program are presented. Better understanding of these neuroplasticity changes would allow researchers to design and provide more beneficial rehabilitation schemes to stroke patients.

¿Es diferente la conectividad estructural en niños y adolescentes familiares de pacientes con trastorno bipolar? Una revisión narrativa según estudios con DTI

Introducción: El trastorno afectivo bipolar (TAB) se ha asociado con una disminución de la integridad de la sustancia blanca. Los estudios con imágenes con tensor de difusión (DTI) han permitido elucidar con una mayor calidad estos cambios. Debido a la gran heredabilidad del TAB, se han realizado estudios en familiares de pacientes con TAB acerca de la integridad de la sustancia blanca, y se ha encontrado que la conectividad estructural también puede estar afectada. Dicha alteración se ha propuesto como un potencial biomarcador de vulnerabilidad a este trastorno. Sin embargo, los estudios en niños y adolescentes son pocos. Objetivo: Revisar la literatura sobre los cambios en la integridad de la sustancia blanca determinados mediante DTI en niños y adolescentes con alto riesgo. Resultados: Se describe la conectividad estructural cerebral en la población pediátrica en estudios que utilizaron DTI. Se describen los cambios en el proceso de mielinización desde su evolución dentro del neurodesarrollo normal hasta los hallazgos en la anisotropía fraccional (AF) en pacientes con TAB y los familiares en alto riesgo. Conclusiones: Los estudios demuestran que tanto pacientes con TAB como sus familiares en riesgo presentan disminución de la AF en regiones cerebrales específicas. Los estudios en niños y adolescentes con riesgo familiar de TAB señalan una AF reducida en tractos axonales implicados en funciones emocionales y cognitivas. La disminución de la AF puede considerarse como un biomarcador de vulnerabilidad al TAB.

Introduction: Bipolar disorder (BD) has been associated with a decrease in white matter integrity. Diffusion tensor imaging (DTI) studies have enabled these changes to be elucidated with higher quality. Due to BD's high heritability, some studies have been conducted in relatives of BD patients looking at white matter integrity, and have found that structural connectivity may also be affected. This alteration has been proposed as a potential BD biomarker of vulnerability. However, there are few studies in children and adolescents. Objective: To conduct a review of the literature on changes in white matter integrity determined by DTI in high-risk children and adolescents. Results: Brain structural connectivity in the paediatric population is described in studies using DTI. Changes in the myelination process from its evolution within normal neurodevelopment to the findings in fractional anisotropy (FA) in BD patients and their high-risk relatives are also described. Conclusions: Studies show that both BD patients and their at-risk relatives present a decrease in FA in specific brain regions. Studies in children and adolescents with a high risk of BD, indicate a reduced FA in axonal tracts involved in emotional and cognitive functions. Decreased FA can be considered as a vulnerability biomarker for BD.

Efficacy and mechanism of scalp acupuncture for spastic cerebral palsy / 中国针灸

OBJECTIVE@#To observe the clinical efficacy of scalp acupuncture for spastic cerebral palsy (CP), and to explore its possible mechanism based on brain white matter fiber bundles, nerve growth related proteins and inflammatory cytokines.@*METHODS@#A total of 90 children with spastic CP were randomly divided into a scalp acupuncture group and a sham scalp acupuncture group, 45 cases in each group. The children in the two groups were treated with conventional comprehensive rehabilitation treatment. The children in the scalp acupuncture group were treated with scalp acupuncture at the parietal temporal anterior oblique line, parietal temporal posterior oblique line on the affected side, and parietal midline. The children in the sham scalp acupuncture group were treated with scalp acupuncture at 1 cun next to the above point lines. The needles were kept for 30 min, once a day, 5 days a week, for 12 weeks. Before and after treatment, the diffusion tensor imaging (DTI) indexes of magnetic resonance (FA values of corticospinal tract [CST], anterior limb of internal capsule [ICAL], posterior limb of internal capsule [ICPL], genu of internal capsule [ICGL], genu of corpus callosum [GCC], body of corpus callosum [BCC] and splenium of corpus callosum [SCC]), serum levels of nerve growth related proteins (neuron-specific enolase [NSE], glial fibrillary acidic protein [GFAP], myelin basic protein [MBP], ubiquitin carboxy terminal hydrolase-L1 [UCH-L1]) and inflammatory cytokines (interleukin 33 [IL-33], tumor necrosis factor α [TNF-α]), cerebral hemodynamic indexes (mean blood flow velocity [Vm], systolic peak flow velocity [Vs] and resistance index [RI], pulsatility index [PI] of cerebral artery), surface electromyography (SEMG) signal indexes (root mean square [RMS] values of rectus femoris, hamstring muscles, gastrocnemius muscles, tibialis anterior muscles), gross motor function measure-88 (GMFM-88) score, modified Ashworth scale (MAS) score, ability of daily living (ADL) score were observed in the two groups. The clinical effect of the two groups was compared.@*RESULTS@#After treatment, the FA value of each fiber bundle, Vm, Vs, GMFM-88 scores and ADL scores in the two groups were higher than those before treatment (P<0.05), and the above indexes in the scalp acupuncture group were higher than those in the sham scalp acupuncture group (P<0.05). After treatment, the serum levels of NSE, GFAP, MBP, UCH-L1, IL-33, TNF-α as well as RI, PI, MAS scores and RMS values of each muscle were lower than those before treatment (P<0.05), and the above indexes in the scalp acupuncture group were lower than those in the sham scalp acupuncture group (P<0.05). The total effective rate was 95.6% (43/45) in the scalp acupuncture group, which was higher than 82.2% (37/45) in the sham scalp acupuncture group (P<0.05).@*CONCLUSION@#Scalp acupuncture could effectively treat spastic CP, improve the cerebral hemodynamics and gross motor function, reduce muscle tension and spasticity, and improve the ability of daily life. The mechanism may be related to repairing the white matter fiber bundles and regulating the levels of nerve growth related proteins and inflammatory cytokines.

The influence of tissue conductivity on the calculation of electric field in the transcranial magnetic stimulation head model / 生物医学工程学杂志

In transcranial magnetic stimulation (TMS), the conductivity of brain tissue is obtained by using diffusion tensor imaging (DTI) data processing. However, the specific impact of different processing methods on the induced electric field in the tissue has not been thoroughly studied. In this paper, we first used magnetic resonance image (MRI) data to create a three-dimensional head model, and then estimated the conductivity of gray matter (GM) and white matter (WM) using four conductivity models, namely scalar (SC), direct mapping (DM), volume normalization (VN) and average conductivity (MC), respectively. Isotropic empirical conductivity values were used for the conductivity of other tissues such as the scalp, skull, and cerebrospinal fluid (CSF), and then the TMS simulations were performed when the coil was parallel and perpendicular to the gyrus of the target. When the coil was perpendicular to the gyrus where the target was located, it was easy to get the maximum electric field in the head model. The maximum electric field in the DM model was 45.66% higher than that in the SC model. The results showed that the conductivity component along the electric field direction of which conductivity model was smaller in TMS, the induced electric field in the corresponding domain corresponding to the conductivity model was larger. This study has guiding significance for TMS precise stimulation.

Changes in Plasma Amyloid-β Level and Their Relationship With White Matter Microstructure in Patients With Mild Cognitive Impairment / 中国医学科学院学报

Objective To investigate the changes in plasma amyloid-β (Aβ) level and their relationship with white matter microstructure in the patients with amnesic mild cognitive impairment(aMCI) and vascular mild cognitive impairment (vMCI).Methods A total of 36 aMCI patients,20 vMCI patients,and 34 sex and age matched healthy controls (HC) in the outpatient and inpatient departments of the First Affiliated Hospital of Anhui Medical University were enrolled in this study.Neuropsychological scales,including the Mini-Mental State Examination,the Montreal Cognitive Assessment,and the Activity of Daily Living Scale,were employed to assess the participants.Plasma samples of all the participants were collected for the measurement of Aβ42 and Aβ40 levels.All the participants underwent magnetic resonance scanning to obtain diffusion tensor imaging (DTI) data.The DTI indexes of 48 white matter regions of each individual were measured (based on the ICBM-DTI-81 white-matter labels atlas developed by Johns Hopkins University),including fractional anisotropy (FA) and mean diffusivity (MD).The cognitive function,plasma Aβ42,Aβ40,and Aβ42/40 levels,and DTI index were compared among the three groups.The correlations between the plasma Aβ42/40 levels and DTI index of aMCI and vMCI patients were analyzed.Results The Mini-Mental State Examination and the Montreal Cognitive Assessment scores of aMCI and vMCI groups were lower than those of the HC group (all P<0.001).There was no significant difference in the Activity of Daily Living Scale score among the three groups (P=0.654).The plasma Aβ42 level showed no significant difference among the three groups (P=0.227).The plasma Aβ40 level in the vMCI group was higher than that in the HC group (P=0.014),while it showed no significant difference between aMCI and HC groups (P=1.000).The plasma Aβ42/40 levels in aMCI and vMCI groups showed no significant differences from that in the HC group (P=1.000,P=0.105),while the plasma Aβ42/40 level was lower in the vMCI group than in the aMCI group (P=0.016).The FA value of the left anterior limb of internal capsule in the vMCI group was lower than those in HC and aMCI groups (all P=0.001).The MD values of the left superior corona radiata,left external capsule,left cingulum (cingulate gyrus),and left superior fronto-occipital fasciculus in the vMCI group were higher than those in HC (P=0.024,P=0.001,P=0.003,P<0.001) and aMCI (P=0.015,P=0.004,P=0.019,P=0.001) groups,while the MD values of the right posterior limb of internal capsule (P=0.005,P=0.001) and left cingulum (hippocampus) (P=0.017,P=0.031) in the aMCI and vMCI groups were higher than those in the HC group.In the aMCI group,plasma Aβ42/40 level was positively correlated with FA of left posterior limb of internal capsule (r=0.403,P=0.015) and negatively correlated with MD of the right fonix (r=-0.395,P=0.017).In the vMCI group,plasma Aβ42/40 level was positively correlated with FA of the right superior cerebellar peduncle and the right anterior limb of internal capsule (r=0.575,P=0.008;r=0.639,P=0.002),while it was negatively correlated with MD of the right superior cerebellar peduncle and the right anterior limb of internal capsule (r=-0.558,P=0.011;r=-0.626,P=0.003).Conclusions Plasma Aβ levels vary differently in the patients with aMCI and vMCI.The white matter regions of impaired microstructural integrity differ in the patients with different dementia types in the early stage.The plasma Aβ levels in the patients with aMCI and vMCI are associated with the structural integrity of white matter,and there is regional specificity between them.

Research progress in the evaluation of glymphatic system function by the DTI-ALPS method / 中南大学学报(医学版)

The glymphatic system can remove metabolic wastes from the brain, which plays a significant role in maintaining the homeostasis of the central nervous system. It is an important basis for advanced cognitive functions such as learning and memory. Studies have analyzed the function of glymphatic system by diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) recently. Compared with other invasive examinations that require fluorescent tracer technique or the injection of contrast agents, DTI-ALPS can evaluate the hydromechanics of the glymphatic system via quantifying the diffusion rate of water molecules in different directions, which turns out to be a non-invasive in vivo neuroimaging method. The ALPS-index calculated by the DTI-ALPS method is significantly correlated with the cognitive function in diseases of central nervous system and other system and can reflect the dynamic changes of diseases. In general, ALPS-index is expected to become a novel neuroimaging biomarker for predicting prognosis and clinical effects.

Diffusion tensor field estimation based on 3D U-Net and diffusion tensor imaging model constraint / 南方医科大学学报

OBJECTIVE@#To propose a diffusion tensor field estimation network based on 3D U-Net and diffusion tensor imaging (DTI) model constraint (3D DTI-Unet) to accurately estimate DTI quantification parameters from a small number of diffusion-weighted (DW) images with a low signal-to-noise ratio.@*METHODS@#The input of 3D DTI-Unet was noisy diffusion magnetic resonance imaging (dMRI) data containing one non-DW image and 6 DW images with different diffusion coding directions. The noise-reduced non-DW image and accurate diffusion tensor field were predicted through 3D U-Net. The dMRI data were reconstructed using the DTI model and compared with the true value of dMRI data to optimize the network and ensure the consistency of the dMRI data with the physical model of the diffusion tensor field. We compared 3D DTI-Unet with two DW image denoising algorithms (MP-PCA and GL-HOSVD) to verify the effect of the proposed method.@*RESULTS@#The proposed method was better than MP-PCA and GL-HOSVD in terms of quantitative results and visual evaluation of DW images, diffusion tensor field and DTI quantification parameters.@*CONCLUSION@#The proposed method can obtain accurate DTI quantification parameters from one non-DW image and 6 DW images to reduce image acquisition time and improve the reliability of quantitative diagnosis.

Research progress of glymphatic system and central nervous system diseases / 中国神经精神疾病杂志

The glymphatic system is a unique network of the central nervous system that facilitates the removal of metabolic waste from the brain and maintains homeostasis.The glymphatic system is relatively active during sleep,and its physiological function is affected by many factors.The application of non-invasive imaging techniques to evaluate the function of the glymphatic system has promoted the development of clinical studies.More and more studies have demonstrated the association between the function of glymphatic system and the pathogenesis of neurodegenerative diseases,cerebrovascular diseases and other central nervous system diseases.The glymphatic system is expected to become a novel target for predicting prognosis of central nervous system diseases and clinical effects.

Glymphatic system functional changes of bilateral cerebral hemispheres in early-stage Parkinson disease patients complicated with unilateral limb motor symptoms / 中国医学影像技术

Objective To observe the glymphatic system functional changes of bilateral cerebral hemispheres in early-stage Parkinson disease(PD)patients complicated with unilateral limb motor symptoms.Methods A total of 52 early-stage PD patients complicated with unilateral limb motor symptoms were prospectively enrolled,including 21 cases of left-onset PD(LPD group),31 cases of right-onset PD(RPD group).Meanwhile,28 healthy individuals were recruited as healthy controls(HC group).Clinical data and indices of diffusion tensor imaging analysis along the perivascular space(DTI-ALPS)were compared among 3 groups and between each 2 groups.The correlations of DTI-ALPS indices and clinical scales were analyzed.Results Significant difference of Hamilton depression scale(HAMD)score was found among 3 groups(P＜0.05).HAMD score of LPD group and RPD group were higher than that of HC group(both P＜0.017).There were significant differences of left and right cerebral hemispheres DTI-ALPS(DTI-ALPS_L,DTI-ALPS_R)indices among 3 groups(both P＜0.05).DTI_ALPS_R in LPD group was lower than that in HC group(P＜0.017),and DTI_ALPS_L in RPD group was lower than that in HC group(P＜0.017).No obvious correlation of bilateral cerebral hemisphere DTI-ALPS indices with clinical scales was detected in PD patients(all P＞0.05).Conclusion Like that of motor symptoms,glymphatic system dysfunction of PD patients had characteristics of laterality,manifested as DTI_ALPS_R decreased in LPD patients while DTI_ALPS_L decreased in RPD patients.

Application of diffusion tensor imaging in post-stroke depression / 国际脑血管病杂志

Post-stroke depression (PSD) is a common emotional disorder after stroke, which can affect cognitive function of patients and have adverse effect on post-stroke recovery. Diffusion tensor imaging (DTI) can reveal the microstructure of white matter. At present, it has been applied in the study of the pathogenesis of various diseases. This article reviews the application of DTI technology in depression, stroke, and PSD, aiming to make early predictions of PSD from multiple perspectives to improve its outcomes.

Diffusion Tensor Imaging in the White Matter Changes of Patients with Pituitary Macroadenoma / 昆明医科大学学报

Objective To investigate the microstructural changes in white matter of pituitary adenoma patients when the anterior visual pathway is compressed using diffusion tensor imaging(DTI)and discuss the clinical significance of these changes.Methods Clinical and MRI data of 25 patients with pituitary adenomas and 25 matched healthy controls were prospectively included.Tract-based spatial statistics(TBSS)was carried out to investigate difference in white matter integrity between 2 groups,which was measured using fractional anisotropy(FA).A correlation between visual function evaluation index and regional FA value was examined using correlation analysis.Results The FA values of bilateral optic radiations and inferior fronto-occipital fasciculus were significantly lower in the research group.The FA values of left optic radiation and inferior fronto-occipital fasciculus were positively correlated to mean deviation and visual field index,negatively correlated to patten standard deviation.The FA values of bilateral optic radiations and inferior fronto-occipital fasciculus were negatively correlated with Bulbo-pontine height.Conclusion Patients with pituitary adenoma may experience damage to the bilateral optic radiation and inferior fronto-occipital fasciculus after compression of the anterior visual pathway,which may affect the patient's visual function,further indicating that DTI can quantitatively assess the microstructure damage of the visual pathway in patients with pituitary adenoma.