Microstructural status of ipsilesional and contralesional corticospinal tract correlates with motor skill in chronic stroke patients

Greater loss in structural integrity of the ipsilesional corticospinal tract (CST) is associated with poorer motor outcome in patients with hemiparetic stroke. Animal models of stroke have demonstrated that structural remodeling of white matter in the ipsilesional and contralesional hemispheres is associated with improved motor recovery. Accordingly, motor recovery in patients with stroke may relate to the relative strength of CST degeneration and remodeling. This study examined the relationship between microstructural status of brain white matter tracts, indexed by the fractional anisotropy (FA) metric derived from diffusion tensor imaging (DTI) data, and motor skill of the stroke‐affected hand in patients with chronic stroke. Voxelwise analysis revealed that motor skill significantly and positively correlated with FA of the ipsilesional and contralesional CST in the patients. Additional voxelwise analyses showed that patients with poorer motor skill had reduced FA of bilateral CST compared to normal control subjects, whereas patients with better motor skill had elevated FA of bilateral CST compared to controls. These findings were confirmed using a DTI‐tractography method applied to the CST in both hemispheres. The results of this study suggest that the level of motor skill recovery achieved in patients with hemiparetic stroke relates to microstructural status of the CST in both the ipsilesional and contralesional hemispheres, which may reflect the net effect of degeneration and remodeling of bilateral CST. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.     

磁共振弥散张量成像在基底节区高血压脑出血致皮质脊髓束损伤中的应用研究

目的 探讨磁共振弥散张量成像(DTI)技术评价基底节区高血压脑出血(HICH)患者皮质脊髓束(CST)受损程度的意义及其与肌力恢复的关系.方法 徐州医学院附属医院神经外科自2006年11月至2009年5月行小骨窗开颅血肿清除术治疗单侧基底节区HICH患者35例,术后10 d应用3.0T磁共振DTI技术检测患者和10例健康志愿者CST,应用Functool软件进行图像分析观察CST损伤程度,HICH患者康复治疗2月后采用Brunnstrom标准进行肢体肌力检查,分析CST损伤程度与肢体肌力的相关性.结果 10例健康志愿者CST显示清晰.35例HICH患者CST受损的模式有3种:纤维束显示达正常侧的2/3或相仿(11例),患者肢体肌力恢复最好;纤维束显示小于正常侧的2/3(18例),患者肢体肌力恢复较好;纤维柬显示小于正常侧的1/3(6例),患者肢体肌力恢复最差.CST受损患者患侧的FA值均较健侧降低,差异有统计学意义(P<0.05).3种模式CST损伤患者患侧的FA值、肢体肌力不同,差异均有统计学意义(P=0.000).患者CST损伤程度与肌力恢复水平存在负相关关系(r=0.931,P=0.000).结论 应用磁共振DTI技术可显示脑内白质纤维束的走形及分布,能够早期检测HICH患者CST的损伤程度,对患者肢体运动功能损伤的评估、判断预后有重要的临床意义.     

Corticospinal tract degeneration and possible pathogenesis in ALS evaluated by MR diffusion tensor imaging.

BACKGROUND: MR diffusion tensor imaging (DTI) appears to be a powerful method to investigate the neuronal and axonal fibre distribution in the human brain. Changes in diffusion characteristics of water molecules in the white matter can be estimated as the apparent diffusion coefficient (ADC) and the fractional anisotropy index (FA). OBJECTIVES: To characterize DTI changes at three different levels in the corticospinal tract (CST) (corona radiata, internal capsule and pons) in order to elucidate if pathogenesis of ALS is due to an anterograde or retrograde axonal degeneration. METHODS: We studied eight ALS patients with clinical signs of upper motor neuron involvement. The patients were compared with 11 healthy age-matched controls. RESULTS: ADC was significantly increased in the CST in ALS patients at the level of the internal capsule and also increased in the pons, but without statistical significance. ADC was unchanged at the level of the corona radiata. FA was significantly reduced at the lowest level (pons), only tended to be reduced in the internal capsule, but was also unchanged in the corona radiata. CONCLUSIONS: Segmentation of the CST into three regions supports the hypothesis of a 'dying back' mechanism in ALS and suggests that ADC is a more sensitive measure than FA to detect pathological changes in ALS.     

The corticospinal tract in Sturge-Weber syndrome: a diffusion tensor tractography study

OBJECTIVE: To utilize diffusion tensor tractography and evaluate the integrity of the corticospinal tract in children with unilateral Sturge-Weber syndrome (SWS). METHODS: Sixteen children (age: 1.5-12.3 years) with SWS involving one hemisphere and varying degrees of motor deficit, underwent magnetic resonance imaging (MRI) as part of a prospective clinical research study. Diffusion tensor imaging (DTI) was obtained and fiber tracking of the corticospinal tract was performed yielding average FA and ADC values along the pathway. These values were compared between the two hemispheres (affected vs. unaffected) and also correlated with the degree of motor deficits, after correction for age. RESULTS: Corticospinal tract FA values on the side of the affected hemisphere were lower (p=0.008) and ADC values were higher (p=0.011) compared to the normal side. Furthermore, FA and ADC values on the side of the angioma did not show the normal age-related variations, which the contralateral corticospinal pathway values did demonstrate. Although none of the patients had severe hemiparesis, those with moderate motor deficit had increased ADC values, as compared to those with mild (p=0.009) or no motor deficit (p=0.045). CONCLUSION: MRI with DTI shows abnormalities of the corticospinal tract in children with SWS even before severe motor impairment develops. Thus, DTI can be a clinically useful method to evaluate the integrity of the corticospinal tract in young children who are at risk for progressive motor dysfunction.     

Test–retest reliability and minimal detectable change of corticospinal tract integrity in chronic stroke

Diffusion tensor imaging (DTI) can be used to index white matter integrity of the corticospinal tract (CST) after stroke; however, the psychometric properties of DTI‐based measures of white matter integrity are unknown. The purpose of this study was to examine test–retest reliability as determined by intraclass correlation coefficients (ICC) and calculate minimal detectable change (MDC) of DTI‐based measures of CST integrity using three different approaches: a Cerebral Peduncle approach, a Probabilistic Tract approach, and a Tract Template approach. Eighteen participants with chronic stroke underwent DTI on the same magnetic resonance imaging scanner 4 days apart. For the Cerebral Peduncle approach, a researcher hand drew masks at the cerebral peduncle. For the Probabilistic Tract approach, tractography was seeded in motor areas of the cortex to the cerebral peduncle. For the Tract Template approach, a standard CST template was transformed into native space. For all approaches, the researcher performing analyses was blind to participant number and day of data collection. All three approaches had good to excellent test–retest reliability for fractional anisotropy (FA; ICCs >0.786). Mean diffusivity, axial diffusivity, and radial diffusivity were less reliable than FA. The ICC values were highest and MDC values were the smallest for the most automated approach (Tract Template), followed by the combined manual/automated approach (Probabilistic Tract) then the manual approach (Cerebral Peduncle). The results of this study may have implications for how DTI‐based measures of CST integrity are used to define impairment, predict outcomes, and interpret change after stroke.     

Detecting abnormalities of corpus callosum connectivity in autism using magnetic resonance imaging and diffusion tensor tractography

The corpus callosum (CC) has emerged as one of the primary targets of autism research. To detect aberrant CC interhemispheric connectivity in autism, we performed T1-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI)-based tractography in 18 children with high functioning autism (HFA) and 16 well-matched typically developing (TD) children. We compared global and regional T1 measures (CC volume, and CC density), and the DTI measures [fractional anisotropy (FA), apparent diffusion coefficient (ADC), average fiber length (AFL), and fiber number (FN)] of transcallosal fibers, between the two groups. We also evaluated the relationships between scores on the Childhood Autism Rating Scale (CARS) and CC T1 or DTI measurements. Significantly less white matter density in the anterior third of the CC, and higher ADC and lower FN values of the anterior third transcallosal fiber tracts were found in HFA patients compared to TD children. These results suggested that the anterior third CC density and transcallosal fiber connectivity were affected in HFA children.     

Spatial Profiling of the Corticospinal Tract in Amyotrophic Lateral Sclerosis Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) was used as a noninvasive method to evaluate the anatomy of the corticospinal tract (CST) and the pattern of its degeneration in amyotrophic lateral sclerosis (ALS). METHODS: Fourteen patients with ALS and 15 healthy controls underwent DTI. Parameters reflecting coherence of diffusion (fractional anisotropy, FA), bulk diffusion (apparent diffusion coefficient, ADC), and directionality of diffusion (eigenvalues) parallel to (lambda( parallel)) or perpendicular to (lambda( perpendicular)) fiber tracts were measured along the intracranial course of the CST. RESULTS: FA and lambda( parallel) increased, and ADC and lambda( perpendicular) decreased progressively from the corona radiata to the cerebral peduncle in all subjects. The most abnormal finding in patients with ALS was reduced FA in the cerebral peduncle contralateral to the side of the body with the most severe upper motor neuron signs. lambda( parallel) was increased in the corona radiata. Internal capsule FA correlated positively with symptom duration, and cerebral peduncle ADC positively with the Ashworth spasticity score. CONCLUSION: There is a spatial dependency of diffusion parameters along the CST in healthy individuals. Evidence of intracranial CST degeneration in ALS was found with distinct diffusion changes in the rostral and caudal regions.     

磁共振弥散张量成像在急性脑梗死患者运动功能预后判断临床价值研究

目的判断磁共振弥散张量成像(DTI)在急性脑梗死患者运动功能预后的临床价值。方法对30例急性脑梗死患者行磁共振(MRI)和DTI影像学检查,检测参数为部分各向异性值(FA),同时对脑梗死患者进行Brunnstrom评分。结果脑梗死患者患侧白质FA值显著低于健侧(P<0.01),统计学分析结果显示患侧皮质脊髓束损伤程度与偏瘫侧肌力明显相关(Y=0.774,P<0.05),30例患者DTI分级与肌力减弱程度呈正相关(rs=0.75,P<0.05)。结论 DTI技术能清楚显示脑梗死白质纤维束的受累程度,能够较好的评价患者运动功能损伤,对急性脑梗死患者运动功能预后判断有重要临床价值。     

Whole brain‐based analysis of regional white matter tract alterations in rare motor neuron diseases by diffusion tensor imaging

Different motor neuron disorders (MND s ) are mainly defined by the clinical presentation based on the predominance of upper or lower motor neuron impairment and the course of the disease. Magnetic resonance imaging (MRI) mostly serves as a tool to exclude other pathologies, but novel approaches such as diffusion tensor imaging (DTI) have begun to add information on the underlying pathophysiological processes of these disorders in vivo. The present study was designed to investigate three different rare MNDs, i.e., primary lateral sclerosis (PLS, N = 25), hereditary spastic paraparesis (HSP, N = 24), and X‐linked spinobulbar muscular atrophy (X‐SBMA, N = 20), by use of whole‐brain‐based DTI analysis in comparison with matched controls. This analysis of white matter (WM) impairment revealed widespread and characteristic patterns of alterations within the motor system with a predominant deterioration of the corticospinal tract (CST) in HSP and PLS patients according to the clinical presentation and also in patients with X‐SBMA to a lesser degree, but also WM changes in projection s to the limbic system and within distinct areas of the corpus callosum (CC), the latter both for HSP and PLS. In summary, DTI was able to define a characteristic WM pathoanatomy in motor and extra‐motor brain areas, such as the CC and the limbic projectional system, for different MNDs via whole brain‐based FA assessment and quantitative fiber tracking. Future advanced MRI‐based investigations might help to provide a fingerprint‐identification of MNDs. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.     

Neurite orientation dispersion and density imaging quantifies corticospinal tract microstructural organization in children with unilateral cerebral palsy

Children with unilateral cerebral palsy (UCP) due to early brain injury exhibit disrupted connectivity of corticospinal tracts (CSTs), which can be quantified using diffusion‐weighted magnetic resonance imaging (DWI). Diffusion tensor imaging (DTI) is commonly used to quantify white matter organization, however, this model lacks the biological specificity to accurately describe underlying microstructural properties. Newer approaches, such as neurite orientation dispersion and density imaging (NODDI), may provide more biologically accurate information regarding CST microstructure. In this study, we directly compared metrics of CST microstructure using NODDI and DTI models to characterize the microstructural organization of corticospinal pathways. Twenty participants with UCP participating in a neuromodulation/rehabilitation intervention underwent imaging including multi‐shell DWI; 10 participants' datasets were adequately completed for neuroimaging analysis. Task fMRI‐guided probabilistic tractography from motor cortex to brainstem was performed at baseline and follow‐up to reconstruct the CSTs. Diffusion metrics were compared between hemispheres at baseline, and between baseline and follow‐up to test for intervention effects. Correlation analyses were used to compare baseline metrics to changes in hand function following the intervention. DTI results showed that mean fractional anisotropy in lesioned and nonlesioned CSTs did not significantly differ, but mean, axial, and radial diffusivity were greater in the lesioned CST. For NODDI, intracellular volume fraction (ICVF) and orientation dispersion index (ODI) were lower in the lesioned CST. Unimanual function was strongly correlated with ICVF, but not FA. NODDI may reveal distinct properties of CST microstructure that are linked to motor function, indicating their potential in characterizing brain structure and development.     

Association of White Matter Integrity With Executive Function and Antidepressant Treatment Outcome in Patients With Late-Life Depression

ObjectiveWhile patients with late-life depression (LLD) often exhibit microstructural white matter alterations that can be identified with diffusion tensor imaging (DTI), there is a dearth of information concerning the links between DTI findings and specific cognitive performance, as well as between DTI measures and antidepressant treatment outcomes.DesignNeuroimaging and cognitive tests were conducted at baseline in 71 older adults participating in a larger, 8-week duration antidepressant randomized controlled trial. Correlations between DTI measures of white matter integrity evaluated with tract-based spatial statistics, baseline neurocognitive performance, and prospective antidepressant treatment outcome were evaluated.ResultsFractional anisotropy (FA), an index of white matter integrity, was significantly positively associated with better cognitive function as measured by the Initiation/Perseveration subscale of the Dementia Rating Scale in the bilateral superior longitudinal fasciculus (SLF), bilateral SLF-temporal, and right corticospinal tract (CST). An exploratory analysis limited to these tracts revealed that increased FA in the right CST, right SLF, and right SLF-temporal tracts was correlated with a greater decrease in depressive symptoms. Increased FA in the right CST predicted a greater chance of remission, while increased FA in the right CST and the right SLF predicted a greater chance of treatment response.ConclusionIn late-life depression LLD subjects, white matter integrity was positively associated with executive function in white matter tracts which act as key connecting structures underlying the cognitive control network. These tracts may play a role as a positive prognostic factor in antidepressant treatment outcome.     

Diffusion tensor imaging patterns differ in bulbar and limb onset amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is characterized by pronounced clinical heterogeneity in terms of onset and disease progression. Widespread changes in white matter fibres could be observed by diffusion tensor imaging (DTI), which detects alterations in the degree (diffusivity, ADC) and directedness (fractional anisotropy, FA) of proton movement. The aim of the current study was to determine whether different ALS onset types were reflected in different DTI brain patterns.

Methods

Seventeen patients with a diagnosis of ALS (6 bulbar, 11 limb onset) and seventeen age-matched controls received 1.5T DTI, where FA and ADC were analyzed using statistical parametric mapping.

Results

In ALS patients, an increased diffusivity in the white matter was found below the precentral gyrus and along the corticospinal tract (CST) right into the internal capsule. The FA was decreased in the posterior limb of internal capsule and in the subcortical white matter in the precentral gyrus. In bulbar onset increased diffusivity was found in the CST, whilst in limb onset, frontal subcortical areas displayed an increased diffusivity.

Conclusion

DTI changes can be regarded as prominent features in ALS. Herein we were able to demonstrate discriminating brain DTI patterns due to bulbar or limb onset.     

Motor function outcomes of pediatric patients with hemiplegic cerebral palsy after rehabilitation treatment:a diffusion tensor imaging study

Previous diffusion tensor imaging(DTI) studies regarding pediatric patients with motor dysfunction have confirmed the correlation between DTI parameters of the injured corticospinal tract and the severity of motor dysfunction. There is also evidence that DTI parameters can help predict the prognosis of motor function of patients with cerebral palsy. But few studies are reported on the DTI parameters that can reflect the motor function outcomes of pediatric patients with hemiplegic cerebral palsy after rehabilitation treatment. In the present study, 36 pediatric patients with hemiplegic cerebral palsy were included. Before and after rehabilitation treatment, DTI was used to measure the fiber number(FN), fractional anisotropy(FA) and apparent diffusion coefficient(ADC) of bilateral corticospinal tracts. Functional Level of Hemiplegia scale(Fx L) was used to assess the therapeutic effect of rehabilitative therapy on clinical hemiplegia. Correlation analysis was performed to assess the statistical interrelationship between the change amount of DTI parameters and Fx L. DTI findings obtained at the initial and follow-up evaluations demonstrated that more affected corticospinal tract yielded significantly decreased FN and FA values and significantly increased ADC value compared to the less affected corticospinal tract. Correlation analysis results showed that the change amount of Fx L was positively correlated to FN and FA values, and the correlation to FN was stronger than the correlation to FA. The results suggest that FN and FA values can be used to evaluate the motor function outcomes of pediatric patients with hemiplegic cerebral palsy after rehabilitation treatment and FN is of more significance for evaluation.     

Diffusion tensor imaging abnormalities in focal cortical dysplasia

PURPOSE: Focal cortical dysplasia (FCD) is one of the most common underlying pathologic substrates in patients with medically intractable epilepsy. While magnetic resonance imaging (MRI) evidence of FCD is an important predictor of good surgical outcome, conventional MRI is not sensitive enough to detect all lesions. Previous reports of diffusion tensor imaging (DTI) abnormalities in FCD suggest the potential of DTI in the detection of FCD. The purpose of this study was to study subcortical white matter underlying small lesions of FCD using DTI. METHODS: Five patients with medically intractable epilepsy and FCD were investigated. Diffusion tensor imaging images were acquired (20 contiguous 3 mm thick axial slices) with maps of fractional anisotropy (FA), trace apparent diffusion coefficient (trace/3 ADC), and principal eigenvalues (ADC parallel and ADC perpendicular to white matter tracts) being calculated for each slice. Region of interest analysis was used to compare subcortical white matter ipsilateral and contralateral to the lesion. RESULTS: Three subjects with FCD associated with underlying white matter hyperintensities on T2 weighted MRI were observed to have increased trace/3 ADC, reduced fractional anisotropy and increased perpendicular water diffusivity which was greater than the relative increase in the parallel diffusivity. No DTI abnormalities were identified in two patients with FCD without white matter hyperintensities on conventional T2-weighted MRI. CONCLUSIONS: While DTI abnormalities in FCD with obvious white matter involvement are consistent with micro-structural degradation of the underlying subcortical white matter, DTI changes were not identified in FCD lesions with normal appearing white matter.     

MR spectroscopy and diffusion tensor imaging of the brain in congenital muscular dystrophy with merosin deficiency: metabolite level decreases, fractional anisotropy decreases, and apparent diffusion coefficient increases in the white matter

Brain magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in one patient with merosin-deficient congenital muscular dystrophy (MDCMD) revealed significant metabolite (choline, creatine, N-acetyl aspartate) level reductions, fractional anisotropy (FA) reduction and increased apparent diffusion coefficient (ADC) in the white matter (p<0.01, all). In the gray matter, the MRS properties did not differ significantly from those in controls. The ADC and FA, however, differed significantly as in the white matter, although the differences were less pronounced. This is the first quantitative MR study of the brain in a patient with MDCMD, which revealed that the concentrations of all MRS measured metabolites were decreased only in the white matter. This observation, combined with the DTI observed ADC increases and FA decrease, indicated a presence of vasogenic edema in the white matter.     

在体磁共振波谱及扩散张力成像观察肌萎缩性侧索硬化的病理变化的研究

目的结合磁共振波谱成像(MRSI)以及扩散张力成像(DTI)技术及磁共振影像(MRI)对肌萎缩性侧索硬化(ALS)进行对照研究,评价MRSI、DTI、MRI在ALS诊断中的作用。方法采用MRSI、DTI及MRI技术对ALS患者及对照组进行扫描,观察沿皮质脊髓束(CST)走行区域包括中央前回皮层下(SWM)、半卵圆中心(CS)、侧脑室旁白质(PV)、内囊后肢(PIC)、大脑脚(CP)的各向异性比(FA)以及平均扩散率(MD),以及SWM、PV、PIC平面氮乙酰门冬胺酸(NAA)与肌酸(Cr)比值在对照组及ALS患者的改变,并比较不同扫描序列在ALS诊断的作用。结果ALS的总FA较对照组明显降低(P<0.001),在CST走行区的SWM、CS、PV和PIC平面,ALS组的FA较对照组明显降低(P<0.05),MD在ALS组有升高的趋势,但无统计学差异。ALS组的NAA/Cr较对照组明显降低(P<0.05),在SWM和PV平面ALS组的NAA/Cr较对照组降低明显(P<0.05)。对T1WI、T2WI与FLAIR序列判断结果显示,对照组与ALS组间MRI的表现无明显差异。结论MRSI与DTI结合能够早期定量探测ALS患者CST的轴索损伤,SWM、CS、PV和PIC平面的FA,在SWM和PV的NAA/Cr为有效的指标。ALS与对照组MRI的表现则无明显差异。     

In vivo characterization of emerging white matter microstructure in the fetal brain in the third trimester

The third trimester of pregnancy is a period of rapid development of fiber bundles in the fetal white matter. Using a recently developed motion‐tracked slice‐to‐volume registration (MT‐SVR) method, we aimed to quantify tract‐specific developmental changes in apparent diffusion coefficient (ADC), fractional anisotropy (FA), and volume in third trimester healthy fetuses. To this end, we reconstructed diffusion tensor images from motion corrected fetal diffusion magnetic resonance imaging data. With an approved protocol, fetal MRI exams were performed on healthy pregnant women at 3 Tesla and included multiple (2–8) diffusion scans of the fetal head (1–2 b = 0 s/mm² images and 12 diffusion‐sensitized images at b = 500 s/mm²). Diffusion data from 32 fetuses (13 females) with median gestational age (GA) of 33 weeks 4 days were processed with MT‐SVR and deterministic tractography seeded by regions of interest corresponding to 12 major fiber tracts. Multivariable regression analysis was used to evaluate the association of GA with volume, FA, and ADC for each tract. For all tracts, the volume and FA increased, and the ADC decreased with GA. Associations reached statistical significance for: FA and ADC of the forceps major; volume and ADC for the forceps minor; FA, ADC, and volume for the cingulum; ADC, FA, and volume for the uncinate fasciculi; ADC of the inferior fronto‐occipital fasciculi, ADC of the inferior longitudinal fasciculi; and FA and ADC for the corticospinal tracts. These quantitative results demonstrate the complex pattern and rates of tract‐specific, GA‐related microstructural changes of the developing white matter in human fetal brain.     

抑郁症患者脑白质变化初步研究

目的：利用能够提示脑白质纤维完整性的磁共振弥散张量成像（DTI）探讨首发和复发重性抑郁症患者脑白质纤维的变化及其差异。方法：20例重性抑郁症患者（首发9例，复发11例）和20名正常对照者均经常规磁共振成像（MRI）平扫，未发现异常者继续进行DTI和结构MRI（3D）扫描，基于像素的全脑分析技术对DTI数据进行分析。结果：与对照组相比较，抑郁症组白质纤维结构在双侧额中回、右顶下小叶及双侧脑岛等区域白质的各向异性值（FA）显著降低（各脑区P均〈0.001，cluster〉30像素）;与首发抑郁症患者相比较，复发抑郁症患者右侧额上回、右顶叶、中央前回、中央后回及右顶下小叶等区域FA值降低更为显著（各脑区P均〈0.001，cluster〉10像素）。结论：重性抑郁症患者存在脑白质异常，抑郁反复发作会导致脑白质损害进一步加重。     

Analysis of diffusion tensor parameters in spinocerebellar ataxia type 3 and type 10 patients

IntroductionThere is a dearth of studies of spinocerebellar ataxias (SCAs) and diffusion tensor magnetic resonance imaging (DTI).ObjectiveTo analyze changes observed in DTI parameters and correlate these to clinical findings in SCA3 and SCA10 patients.MethodsSCA3 (n = 19) and SCA10 (n = 18) patients were compared with a similar number of controls and assessed clinically and with the scale for the assessment and rating of ataxia (SARA) before undergoing the same MRI protocol. TRACULA (TRActs Constrained by UnderLying Anatomy) software was used to analyze the DTI metrics FA, AD, RD and MD.ResultsMore white matter fiber tracts with changes in diffusivity were found in SCA3 patients than in SCA10 patients. There was a reduction in AD in altered fiber tracts in SCA3 and a greater increase in RD in SCA10. In the SCA3 patients, FA was reduced in the corticospinal tract (CST) and inferior longitudinal fasciculus (ILF), but this was not observed in the SCA10 patients. SARA score was correlated with DTI findings in SCA3 but not in SCA10.ConclusionChanges were observed in DTI for both SCA3 and SCA10 but were more widespread in SCA3. Our finding of myelin-sheath changes in SCA10 and secondary axonal changes in SCA3 may reflect the more rapid, aggressive clinical course of SCA3.