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.

Structural asymmetries in neonatal brain white matter: a diffusion tensor imaging study / 中华放射学杂志

Objective:To explore the asymmetry of neonatal brain white matter using fractional anisotropy (FA) parameter generated from diffusion tensor imaging (DTI).Methods:From January 2011 to June 2013, 88 neonates with normal cranial MRI performance, aged 1-14 (7.7±0.3) days and gestational age 31-42 (37.5±0.3) weeks, were retrospectively collected from the First Affiliated Hospital of Xi′an Jiaotong University. According to the gestational age at birth, the neonates were divided into preterm group (37 cases) and term group (51 cases). DTI was processed to generate FA parametric maps. Tract-based spatial statistics (TBSS) was used to analyze the asymmetry in neonatal white matter. Regions of interest were placed in bilaterally symmetrical white matter tracts. The white matter tracts included the bilateral anterior thalamic radiation, corticospinal tract-posterior limb of the inner capsule (CST-IC), corticospinal tract-corona radiata, cingulum hippocampus part (CGH), inferior frontal occipital fasciculus (IFOF), inferior longitudinal fasciculus (ILF), superior longitudinal fasciculus (SLF), uncinate fasciculus, superior longitudinal fasciculus temporal part (SLF-temp). The FA value was measured and asymmetry index (AI) was calculated. The independent-sample t test or Mann-Whitney U test was used to compare the AI of each tract between the preterm and term groups. Partial correlation was used to analyze the effects of neonatal gestational age and birth anthropometric measures on the asymmetry of neonate at birth. Results:The results of TBSS showed that the left lateralized areas of brain white matter in the neonatal period were mainly located in the corticospinal tract, external capsule and genu of corpus callosum. The right lateralized areas of brain white matter in the neonatal period were mainly located in the optic radiation and splenium of corpus callosum. In both the preterm and term groups, the tracts related to motor (CST-IC) and language function (ILF, SLF, SLF-temp) were left asymmetry. The CGH of the preterm and the term neonates were right asymmetry, and AI was -0.086±0.114 and -0.140±0.108 respectively, with a statistically significant difference ( t=2.27, P=0.026), while the differences of AI in the remaining tracts were not statistically significant ( P>0.05). Only gestational age was correlated with the AI of ILF ( r=0.234, P=0.033), SLF ( r=0.259, P=0.018), SLF-temp ( r=0.252, P=0.022), CST-IC ( r=0.235, P=0.033). No significant correlation was found between birthweight, head circumference, body length and AI. Conclusions:The asymmetries of brain white matter already exist in neonates aged less than two weeks. The tracts associated with motor and language function are predominantly left asymmetry.

Application of echo-planar imaging correction in diffusion weighted imaging and diffusion tensor imaging of cervical spinal cord / 中华放射学杂志

Objective:To explore the value of echo-planar imaging correction (EPIC) for improving image quality of diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) of cervical cord.Methods:A total of 33 subjects (20 males, 13 females) were scanned on a 3.0 T MR scanner from January to March 2022, and the sequences included T 1WI, DWI and DTI (with and without corrections). Two observers delineated the regions of interest (ROIs) on the fused images of DWI and DTI with T 1WI before and after correction, and measured the average diffusion coefficient (ADC), fractional anisotropy (FA), and offset distance of ROIs between images with and without corrections. The subjective scores of image quality were also evaluated. The ICC or Kappa was used to test the consistency of the quantitative measurement and subjective scores by the two observers. The average values by the two observers would be used for subsequent analysis. The independent pair t-test and Wilcoxon test were used for comparison of objective measurements and Mann-Whitney U test was used for subjective image assessments between images with and without corrections. Results:The measurement data and the subjective scores of the two observers were in good agreement (ICC 0.912-0.999, Kappa 0.778-0.816). The independent sample t-test showed the subjective scores were significantly different for the DWI and DTI images between before and after geometry and/or ADC corrections. The ADC values of C6, the offset distances measured by DWI before and after correction of C4, C5, and C6 and subjective scores were significantly different ( P<0.05); The FA values of C1 and C3, ADC values of C1 and C3, offset distance of C4, C5 and C6 measured by DTI before and after correction and subjective scores were statistically significant ( P<0.001). Conclusion:EPI geometry correction and ADC value correction can significantly reduce geometric distortion, increase image quality, and thus improve the diagnosis accuracy of essential diseases.

Diffusion tensor imaging analysis along the perivascular space derived intracerebral glymphatic system circulatory function on neuromyelitis optica spectrum disorder: a follow-up study for curative effect / 中华放射学杂志

Objective:To evaluate the value of curative effect in neuromyelitis spectrum disease (NMOSD) based on circulatory function evaluation of intracerebral glymphatic system by using diffusion tensor imaging analysis along the perivascular space.Methods:The clinical and imaging data of 23 patients diagnosed with NMOSD at Tianjin Medical University General Hospital from March 2018 to December 2019 were retrospectively analyzed in this study. The clinical data included expanded disability status scale (EDSS), average relapse rate (ARR) and retinal nerve fiber layer (RNFL) thickness at baseline and 1 year follow-up after treatment. Among the 23 NMOSD patients, there were 22 females and 1 male, aged from 21 to 71 (45±13) years old. All the patients underwent MR scans at both baseline and 1 year after treatment, and the scanning sequences included cerebral 3D-T 1WI, T 2WI, diffusion tensor imaging and cervical spinal sagittal 3D-T 2WI, and the cervical spinal cord volume and bilateral diffusion tensor imaging analysis along the perivascular space index (ALPS index) were calculated. The partial correlation test was used to analyze the correlations between ALPS index and the clinical indicators such as EDSS, ARR, and bilateral RNFL, with the control variables as gender, age, years of education and course of disease. The multiple linear regression model was used to analyze the independent predictors for ALPS index and EDSS after treatment. Receiver operating characteristic curve (ROC) and area under the curve (AUC) were used to evaluate the diagnostic value of NMOSD treatment outcome by using ALPS index. Results:When controlling for gender, age, years of education and course of disease, there were significant negative correlations between right ALPS index and EDSS ( r=-0.50, P=0.048), bilateral average ALPS index and EDSS ( r=-0.53, P=0.034), left ALPS index and ARR ( r=-0.58, P=0.018), while there was significant positive correlations between right ALPS index and RNFL ( r=0.88, P=0.008) at 1 year follow-up after treatment. Multiple linear regression analysis showed that cervical spinal cord volume was an independent impact factor of bilateral average ALPS indexes (β=0.24, 95%CI 0.10-0.38, P=0.002), and bilateral average ALPS indexes (β=-3.22, 95%CI -5.97--0.48, P=0.024) and right RNFL (β=-0.05, 95%CI -0.08--0.02, P=0.002) at baseline were the independent impact factors of EDSS after treatment. ROC curve analysis showed that the bilateral average ALPS index at baseline had the best efficacy in predicting the curative effect of NMOSD patients with AUC=0.92. Conclusions:After treatment, NMOSD patients with severe clinical disability, high frequency of disease attack, poor visual performance, and severe cervical spinal cord atrophy have more serious impairment of intracerebral glymphatic system circulatory function. The ALPS index could help in predicting the clinical curative effect of NMOSD patients.

Application of magnetic resonance imaging in nerve fiber tract analysis in a mouse model of stroke / 中华行为医学与脑科学杂志

Objective:To evaluate the cerebral infarct volume and the nerve fiber connectivity between cortical and neurogenesis-related regions in the mouse model of reperfusion after middle cerebral artery occlusion (MCAO) by 11.7 Tesla(11.7 T) magnetic resonance imaging (MRI).Methods:MCAO models were established in SPF grade adult male C57BL/6 mice using the suture-occluded method.MRI scans were performed at 3 days before and 1 day after modeling.Infarct volumes were calculated, and nerve fiber tracking was performed on specific brain regions to analyze the nerve fiber number and the parameters of fractional anisotropy(FA), mean diffusivity(MD), axial diffusivity (AD)and radial diffusivity(RD). SPSS 26.0 was used for statistical analysis, and paired t test was used to compare the data before and after modeling. Results:(1) After MCAO-induced ischemia, the infarct volume was up to (35.11±17.57)mm 3, and the FA value of the infarct area was significantly reduced compared with that of before modeling( t=4.73, P<0.01). (2) At the anterior-posterior(AP): + 1.2 mm section, the results of fiber tracking showed that compared with before modeling, the number of fiber bundles originating from the dorsal horn of the lateral sub-ventricle zone(SVZ)to the cortex reduced ((92 584.20±14 751.00) vs (59 815.60±6 752.46), t=4.87, P<0.01), and the number of fiber bundles projected to the infarcted area reduced ((107 671.40±10 497.57) vs (61 658.60±10 178.21), t=6.43, P<0.01). FA, AD, MD, and RD values were all decreased in different degrees( t=3.38-6.43, all P<0.05). (3) At the AP: -3.8 mm section, the number of fiber bundles originating from the dorsal horn of the SVZ to the cortex decreased (after modeling(96 944.00±18 331.09), before modeling(58 767.80±16 445.25), t=2.99, P<0.05), and the values of FA, AD, MD and RD decreased after ischemia ( t=7.30, 5.05, 6.74, 4.13, all P<0.05). Conclusion:The ultra-high field strength of 11.7 T MRI can accurately detect the following results that the number of nerve fiber bundles from the SVZ to the cortex or infarct area are both significantly reduced, and diffusion tensor parameters are consistently changed in mice after 1 day of ischemia-reperfusion.

Features of white matter degeneration in ALS patients with different onset and spreading pattern by using DTI / 西安交通大学学报(医学版)

【Objective】 To explore the characteristics of white matter degeneration in amyotrophic lateral sclerosis (ALS) patients with different onset and spreading patterns by using diffusion tensor imaging (DTI). 【Methods】 We enrolled 86 ALS patients and 44 healthy controls. The patients were divided into bulbar- and spinal-onset subgroups according to their onset site, as well as horizon, vertical, interpose/skip, and caudal-rostral subgroups based on the spreading direction of the involved regions. The white matter fiber tracts corresponding to the motor network were set as the region of interest. We used tract-based spatial statistics to evaluate differences between the above groups and the normal controls, with family-wise error (FWE) correction and P<0.05 as statistical significance. 【Results】 The white matter degeneration of ALS patients with bulbar onset was mainly limited to the corona radiation part of the corticospinal tract, while those with spinal onset showed extensive degeneration of corticospinal tract and corpus callosum Ⅲ area (FWE correction, P<0.05). In patients with horizontal and vertical dissemination, decreased integrity of the entire corticospinal tract was found, with patients in the latter group showed extra degeneration in the Ⅲ part of the corpus callosum. Restricted degeneration of the corticospinal tract within bilateral corona radiata was detected in patients with caudal-rostral and interposed/skip spreading pattens (FWE correction, P<0.05). 【Conclusion】 Different onset and disease spread patterns of ALS patients correspond to divergent brain degeneration patterns. The diagnosis, treatment, and management of ALS should fully consider the heterogeneity of the disease.

The effects of transcranial direct current stimulation on cognition and white matter fiber integrity in stroke patients / 中华物理医学与康复杂志

Objective:To observe any effect of transcranial direct current stimulation (tDCS) on the cognition of stroke survivors and the integrity of their white matter fibers.Methods:Thirty persons with post-stroke cognitive impairment (PSCI) were randomly divided into an experimental group ( n=15) and a control group ( n=15). In addition to basic drug therapy and routine cognition training, the experimental group received 20 minutes of tDCS daily, 5 days per week for 3 weeks, while the control group received sham tDCS stimulation. Before and after the treatment, both groups′ cognitive functioning was evaluated using the mini-mental state examination (MMSE) and the Montreal cognitive assessment scale (MoCA). Their ability in the activities of daily living (ADL) was quantified using the modified Barthel index (MBI). Diffusion tensor imaging (DTI) was employed to observe any changes in the integrity of their white matter fibers. Results:The average MMSE, MOCA and MBI scores of both groups had improved significantly after the treatment, but the improvement in the experimental group was significantly greater than among the controls. The average fractional anisotroposy value of the affected inferior fronto-occipital fasciculus in both groups was positively correlated with the group′s average MMSE score and MoCA score.Conclusion:tDCS can effectively improve the cognition and functioning in the activities of daily living of stroke survivors. Its mechanism may be related to improving the integrity of the white matter fibers involved.

Correlation study of imaging characteristics of diffusion tensor imaging and the Yale Global Tic Severity Scale in children with tic disorders / 中华实用儿科临床杂志

Objective:To explore the correlation between imaging features of children with tic disorders and their features assessed by the Yale Global Tic Severity Scale (YGTSS).Methods:A retrospective study.A total of 33 children with tic disorders treated in the Department of Child Rehabilitation, the First Affiliated Hospital of Xinxiang Medical University from January 2022 to March 2023 were included in the tic disorder group, and 10 healthy age-matched children received physical examination during the same period were included in the healthy control group.Under the functional positioning of functional magnetic resonance imaging (fMRI), the active area of children with tic disorders at varying degrees was found.In the region of interest (ROI), localization monitoring and diffusion tensor imaging (DTI) were performed, and the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were recorded.In the same ROI (bilateral thalamus, genu of internal capsule, splenium of corpus callosum, globus pallidus, caudate nucleus) of children in healthy control group, ADC and FA were recorded.Imaging data were compared between groups using the independent sample t test, and their correlation with YGTSS scores was identified by the Pearson correlation analysis. Results:There were significant differences in ADC of the left thalamus (0.869±0.077 vs.0.794±0.083, P=0.022), the right thalamus (0.853±0.055 vs.0.798±0.054, P=0.014), the left caudate nucleus (0.871±0.121 vs.0.787±0.052, P=0.003) and the right caudate nucleus (0.856±0.075 vs.0.788±0.063, P=0.010) between tic disorder group and healthy control group.No significant differences were detected in ADC of the remaining ROI between groups (all P>0.05). There were significant differences in FA of the left thalamus (0.259±0.050 vs.0.344±0.077, P=0.007), the right thalamus (0.265±0.057 vs.0.347±0.095, P=0.026) and the right caudate nucleus (0.168±0.118 vs.0.309±0.181, P=0.041) between tic disorder group and healthy control group.No significant differences were detected in ADC and FA between children with mild and moderate tic disorders (all P>0.05). ADC of the left thalamus and the right caudate nucleus were significantly correlated with YGTSS scores in children with tic disorders ( r=0.407 and 0.372, respectively; all P<0.05). FA of the right thalamus was negatively correlated with YGTSS scores in children with tic disorders ( r=-0.439, P<0.05). Conclusions:ADC of the thalamus and caudate nucleus, and FA of the right thalamus are significantly correlated with YGTSS scores of children with tic disorders.High ADC of the left thalamus and the right caudate nucleus are correlated with high YGTSS scores, indicating a severe symptom of tic disorder in children.A high FA of the right thalamus is correlated with low YGTSS scores, indicating a mild symptom of tic disorder in children.

Clinical study of scalp acupuncture combined with repeated transcranial magnetic stimulation in the treatment of dysphagia after ischemic stroke / 国际中医中药杂志

Objective:To evaluate the effect of scalp acupuncture combined with repeated transcranial magnetic stimulation (rTMS) on dysphagia after ischemic stroke.Methods:Prospective cohort study. A total of 94 patients with dysphagia after ischemic stroke in our hospital who met the inclusion criteria from December 2020 to February 2022 were randomly divided into two groups with 47 patients in each group. The control group was treated with rTMS and conventional acupuncture, while the scalp acupuncture group was treated with rTMS and scalp acupuncture (scalp acupuncture+seven points at the skull base). Both groups were treated for 4 weeks. Before and after treatment, Traditional Chinese Medicine (TCM) symptoms were scored, and the morphology, movement and food swallowing process of the patient's swallowing anatomy were observed with fiber optic endoscopy (FEES), and assessed by the leakage aspiration scale (PAS). The Yilang Fujishima swallowing efficacy evaluation and standard swallowing assessment (SSA) were used to evaluate swallowing function. The dysphagia quality of life scale (SWAL-QOL) were used to evaluate patients' quality of life. Magnetic resonance diffusion tensor imaging (DTI) scanning was performed to observe the anisotropy fraction (FA value) of the selected region of interest (ROI).Results:During the treatment period, each group dropped off 1 patient, and 92 patients entered the statistics. After treatment, the scores of salivation, food retention, eating and drinking cough in the scalp acupuncture group were significantly lower than those in the control group ( t values were 6.87, 4.90, 5.01, respectively, P<0.01), and the PAS grading was significantly better than that in the control group ( χ2=7.80, P=0.025), the swallowing efficacy evaluation and SWAL-QOL score of Yilang Fujishima were significantly higher than those of the control group ( t=6.81, 5.98, P<0.01), and the SSA score was significantly lower than that of the control group ( t=5.68, P<0.01). The FA values of parieto occipital cortex (0.47 ± 0.06 vs. 0.42 ± 0.04, t=3.16), insular cortex (0.44 ± 0.07 vs. 0.40 ± 0.05, t=3.00) and posterior limb of internal capsule (0.58 ± 0.04 vs. 0.54 ± 0.05, t=2.80) of ROI in the head acupuncture group after treatment were significantly higher than those in the control group ( P<0.05). Conclusion:The scalp acupuncture combined with rTMS can improve the swallowing function of patients with dysphagia after ischemic stroke and improve their quality of life.

Diffusion magnetic resonance imaging of patients with cerebral small vessel disease related cognitive impairment / 国际脑血管病杂志

Cerebral small vessel disease (CSVD) is a group of pathological, imaging and clinical syndromes involving small cerebral vessels with different causes. The incidence rate of CSVD increases with age and is the most important cause of vascular cognitive impairment. Different diffusion imaging techniques can quantify white matter microstructure damage by revealing the diffusion movement of water molecules in specific brain tissues, explore the basis and biophysical mechanisms of tissue change, and have important value for the mechanism research, early diagnosis, progression risk, and therapeutic evaluation of cognitive impairment related to CSVD. This article reviews the research progress of diffusion magnetic resonance imaging in CSVD related cognitive impairment.

Investigation on biological subtypes of depression based on diffusion tensor imaging / 四川精神卫生

BackgroundBeing complex and highly heterogeneous with regard to the etiology and clinical manifestations of depression， neuroimaging studies make a breakthrough for exploring the biological subtypes of depression， while the current data-driven approach for the identification of subtyping depression using structural magnetic resonance imaging （MRI） data is insufficient. ObjectiveTo explore the biological subtypes of depression using diffusion tensor imaging （DTI） and machine learning methods. MethodsA total of 127 patients with depression who attended Beijing Anding Hospital from September 2017 to August 2021 and met the Diagnostic and Statistical Manual of Mental Disorders， fourth edition （DSM-IV） diagnostic criteria were included， and another 80 healthy individuals matched for gender and age were recruited through advertisements in surrounding communities during the same period. DTI findings， demographic characteristics and clinical data were collected from all participants. Tract-based spatial statistics （TBSS） and the Johns Hopkins University （JHU） white matter probability maps were used to extract fractional anisotropy （FA） values of white matter tracts. A semi-supervised machine learning technique was used to identify the subtypes， and the FA values for whole brain white matter of patients and controls were compared. ResultsPatients with depression were classified into two biological subtypes. FA values in multiple tracts including corpus callosum and corona radiata of subtype I patients were smaller than those of healthy controls （P<0.01， FDR corrected）， and FA values in middle cerebellar peduncle， left superior cerebellar peduncle and left cerebral peduncle of subtype II patients were larger than those of healthy controls （P<0.01， FDR-corrected）. Baseline Hamilton Depression Scale-17 item （HAMD-17） score yielded no statistical difference between subtype I and subtype II patients （P>0.05）， while subtype I patients scored lower on HAMD-17 than subtype II patients after 12 weeks of treatment （t=2.410， P<0.05）. ConclusionDepression patients exhibit two biological subtypes with distinct patterns of white matter damage. Furthermore， the subtypes respond differently to the medication treatment. ［Funded by the National Key Research and Development Program of China （number， 2016YFC1307200）， the Scientific Research and Cultivation Program of Beijing Municipal Hospitals （number，PX2023066）， Beijing Anding Hospital， Capital Medical University （number，YJ201904， YJ201911）； www.chictr.org.cn number： ChiCTR-OOC-17012566］

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.

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.

Magnetic resonance and dopamine transporter imaging for the diagnosis of Parkinson´s disease: a narrative review / Ressonância magnética e neuroimagem do transportador de dopamina no diagnóstico da doença de Parkinson: uma revisão narrativa

ABSTRACT Background: the diagnosis of Parkinson's disease (PD) can be challenging, especially in the early stages, albeit its updated and validated clinical criteria. Recent developments on neuroimaging in PD, altogether with its consolidated role of excluding secondary and other neurodegenerative causes of parkinsonism, provide more confidence in the diagnosis across the different stages of the disease. This review highlights current knowledge and major recent advances in magnetic resonance and dopamine transporter imaging in aiding PD diagnosis. Objective: This study aims to review current knowledge about the role of magnetic resonance imaging and neuroimaging of the dopamine transporter in diagnosing Parkinson's disease. Methods: We performed a non-systematic literature review through the PubMed database, using the keywords "Parkinson", "magnetic resonance imaging", "diffusion tensor", "diffusion-weighted", "neuromelanin", "nigrosome-1", "single-photon emission computed tomography", "dopamine transporter imaging". The search was restricted to articles written in English, published between January 2010 and February 2022. Results: The diagnosis of Parkinson's disease remains a clinical diagnosis. However, new neuroimaging biomarkers hold promise for increased diagnostic accuracy, especially in earlier stages of the disease. Conclusion: Future validation of new imaging biomarkers bring the expectation of an increased neuroimaging role in the diagnosis of PD in the following years.

RESUMO Antecedentes: O diagnóstico da doença de Parkinson (DP) pode ser desafiador, principalmente nas fases iniciais da doença, embora tenha critérios clínicos atualizados e validados. Os avanços recentes em neuroimagem na DP, além do seu papel já consolidado de excluir causas secundárias e outras causas neurodegenerativas de parkinsonismo, tem contribuído para uma maior confiabilidade no diagnóstico em diferentes estágios da doença. Nesta revisão, nós destacamos os principais avanços de ressonância magnética e imagem do transportador de dopamina em auxiliar o diagnóstico de DP. Objetivo: realizar uma revisão acerca do conhecimento atual sobre o papel da ressonância magnética e imagem do transportador de dopamina no diagnóstico de doença de Parkinson. Método: Realizamos uma revisão não sistemática da literatura através da base de dados PubMed, utilizando as palavras-chave "Parkinson", "magnetic resonance imaging", "diffusion tensor", "diffusion-weighted", "neuromelanin", "nigrosome-1", "single-photon emission computed tomography", "dopamine transporter imaging". A busca foi restrita a artigos escritos em inglês, publicados entre janeiro de 2010 e fevereiro de 2022. Resultados: O diagnóstico de doença de Parkinson continua sendo um diagnóstico clínico, contudo, novos biomarcadores de neuroimagem são promissores para o aumento da acurácia diagnóstica, especialmente em fases mais precoces da doença. Conclusão: A validação futura de novos biomarcadores de imagem traz a expectativa de um maior papel da neuroimagem no diagnóstico de doença de Parkinson nos próximos anos.

Cingulum bundle integrity in schizophrenia with auditory verbal hallucinations: A diffusion tensor imaging tractographic study

Background & objectives: Cingulum bundle (CB) is frequently implicated in schizophrenia; however, its role in specific symptoms of schizophrenia such as auditory verbal hallucinations (AVHs) is less explored. Few studies have reported association between reduced integrity of CB and severity of AVH. Using a symptom-based approach, this diffusion tensor imaging (DTI) tractographic study was aimed to assess and compare the integrity of CB in schizophrenia with AVH, schizophrenia without AVH and healthy controls. Methods: A total of 92 right-handed adult individuals (aged 18-50 yr) were recruited across three study groups. Those with Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) diagnosis of schizophrenia with AVH (group I; n=30) were compared to those with DSM-5 schizophrenia without lifetime AVH (group II; n=32) and healthy controls (group III; n=30; screened using Mini International Neuropsychiatric Interview version-7.0.0. and negative family history). Clinical assessments (groups I and II) included scale for assessment of positive symptoms, scale for assessment of negative symptoms, clinical global impression-schizophrenia and psychotic symptom rating scale. All participants underwent DTI, and quantitative tract-based measurements of fractional anisotropy (FA) were obtained for images using DTI studio version-3.0. Results: All groups were comparable for age, gender, education and severity of illness. Group I had significantly lower FA values in the cingulate gyrus (CG) part of the left CB compared to groups II and III. No significant difference was found between groups II and III. Interpretation & conclusions: The findings of this study suggest that the disruption in the left CB appears to be specific for AVH-positive schizophrenia. The finding is, however, preliminary subject to replication in future studies. Further investigations are needed to understand its relevance in the context of AVH-positive schizophrenia.

Desempeño de biomarcadores de las imágenes con tensor de difusión en regiones tumorales del glioblastoma. Análisis exploratorio de datos mediante gráficos de zombie y pruebas de diagnóstico / Diffusion tensor imaging-derived biomarkers performance in glioblastoma tumor regions: exploratory data analysis using zombie plots and diagnostic tests

Resumen Introducción: Han sido reportados 11 biomarcadores de imágenes con tensor de difusión (DTI) en las regiones tumorales del glioblastoma. Objetivo: Comparar la eficacia de biomarcadores de glioblastoma mediante gráficos de zombie, que permiten la comparación simultánea en función de razones de verosimilitud. Métodos: Cohorte retrospectiva de 29 sujetos con glioblastoma a quienes se efectuó resonancia magnética cerebral de 3 T. Los eigenvalores mayor, intermedio y menor de ITD se utilizaron para calcular 11 biomarcadores en cinco regiones tumorales: sustancia blanca de apariencia normal (NAWM), edema proximal y distal, tumoral viable y necrosis. Las tablas de contingencia con resultados verdaderos y falsos positivos y negativos permitieron calcular gráficos de zombie basados en el factor de Bayes y pruebas diagnósticas previamente no reportadas. Resultados: Los biomarcadores DM, AF, q, L, Cl, Cp, AR actúan en la zona óptima para el diagnóstico de NAWM. Las regiones de edema proximal y distal, tejido tumoral que se realza con contraste y necrosis no poseen biomarcadores que las identifiquen en un nivel de rendimiento óptimo. Conclusiones: Los biomarcadores DM, AF, q, L, Cl, Cp, AR discriminan el tejido cerebral normal en la zona óptima, pero el rendimiento de otras regiones tumorales se ubica en las zonas de inclusión diagnóstica, exclusión diagnóstica y mediocre.

Abstract Introduction: Using diffusion tensor imaging (DTI), 11 biomarkers have been reported in different glioblastoma regions. Objective: To compare the efficacy of glioblastoma biomarkers using "zombie plots". Methods: Retrospective cohort of 29 subjects with glioblastoma who underwent 3-Tesla brain magnetic resonance imaging. DTI major, intermediate and minor eigenvalues were used to calculate biomarkers at five tumor regions: normal-appearing white matter (NAWM), proximal and distal edema, tumor tissue and necrosis. Contingency tables with true and false positive and negative results allowed the calculation of zombie plots based on the Bayes factor and previously unreported diagnostic tests. Results: The MD, FA, q, L, Cl, Cp and RA biomarkers had a good performance at the optimal zone for NAWM diagnosis. The proximal and distal edema, enhancing rim and necrosis regions do not have biomarkers that identify them with an optimal performance level. Conclusions: Zombie plots allow simultaneous comparison of biomarkers based on likelihood ratios. MD, FA, q, L, Cl, Cp, RA discriminated NAWM normal brain tissue at the optimal zone, but performance for other regions was at the mediocre, diagnostic inclusion and diagnostic exclusion zones.

Applying magnetic resonance diffusion tensor imaging in hyperbaric oxygen treatment of traumatic spinal cord injury in rats / 中华物理医学与康复杂志

Objective:To explore the value of diffusion tensor imaging (DTI) in evaluating the effects of hyperbaric oxygen therapy (HOT) in treating spinal cord injury.Methods:The modified Allen′s method was used to induce a traumatic spinal cord injury in 30 rats who were then divided randomly into an injured group and a treatment group, each of 15. The treatment group was given HOT twice a day for 3 days, then once a day for a total of 4 weeks. The injured group did not receive HOT. DTI was performed (along with Basso-Beattie-Bresnahan (BBB) evaluation) at 0h, 6h, 24h, as well as 3, 7, 14, 21 and 28 days after the operation. Two-factor repeated measures ANOVA was conducted to analyze any differences in the DTI results: the fractional anisotropy, mean apparent diffusivity, radial diffusivity and axial diffusivity, as well as the BBB scores. LSD t-tests were performed to analyze the significance of the differences at different time points.Results:At each time point after 24h the average FA value of the treatment group was significantly higher than the injured group′s average, while its average MD and RD values were significantly lower. Beyond 14 days the average AD value of the treatment group was significantly higher than that of the injured group. The treatment group′s average BBB score was also significantly higher at all the time points beyond 3 days.Conclusions:DTI results can evaluate spinal cord function and provide valuable information for the dynamic assessment of hyperbaric oxygen therapy after a traumatic spinal cord injury, and the therapy promotes the recovery of motor function, at least in rats.

Evaluation of urethral morphology and function in female patients with stress urinary incontinence by static and dynamic pelvic floor MRI and diffusion tensor imaging / 中华放射学杂志

Objective:To explore the value of the static and dynamic pelvic floor MRI and diffusion tensor imaging (DTI) in evaluating the morphology and function of urethra in patients with stress urinary incontinence (SUI).Methods:From July 2020 to February 2021, a total of 28 patients with SUI and 45 age-matched healthy controls were prospectively collected at the First Affiliated Hospital of Zhengzhou University. The static and dynamic pelvic floor MRI and DTI were performed for all subjects. The thickness of internal and external sphincter of middle urethra were measured on static MRI images. The functional urethral length (FUL) was measured both on static and maximal strain phase of dynamic MRI images, then the difference of FUL was calculated. The presence of bladder neck funneling and urethra opening were observed on static and dynamic MRI. The muscle fiber bundle image of urethral sphincter complex was obtained by post-processing of DTI original images. The anisotropy fraction (FA), apparent diffusion coefficient (ADC) and three eigenvalues (λ1, λ2, λ3) of annular sphincter and central longitudinal muscle in middle urethra were measured. The independent sample t test and chi-square test were used to analyse the difference of measured parameters in MRI, parameters of DTI and imaging signs between the two groups. Results:Compared with healthy controls, the SUI patients showed that the thickness of external sphincter in middle urethral and FUL in static status and maximal strain phase were significantly decreased ( t=-3.95, -5.72, -8.41, all P<0.001), the difference of FUL between static status and maximal strain phase was significantly increased ( t=4.41, P<0.001). The positive rate of bladder neck funneling in static status and maximal strain phase, urethral opening in maximal strain phase of SUI group increased significantly (χ2=23.09 , 22.25, 26.59, all P<0.001). In SUI group, the FA value of middle urethral annular sphincter decreased significantly ( t=-3.48, P=0.001), while the ADC, λ2 and λ3 values increased significantly ( t=3.19, 2.15 , 2.06, and P=0.002, 0.038 , 0.046, respectively). There was no significant difference in DTI parameters of middle urethral longitudinal muscle between the two groups (all P>0.05). Conclusions:Static and dynamic MRI and DTI techniques can objectively evaluate the changes of urethral morphology and function of SUI patients. The thinning of the external sphincter in the middle urethra, shortening of the FUL and the destruction of the microstructure of the annular sphincter fiber bundle were the main alterations of SUI patients.