In vivo diffusion tensor imaging of the human calf muscle

PURPOSE: To demonstrate the feasibility of in vivo calf muscle fiber tracking in human subjects. MATERIALS AND METHODS: An EPI-based diffusion tensor imaging (DTI) sequence with six-direction diffusion gradient sensitization was implemented, and DT images were acquired at 3 Tesla on five subjects using an extremity coil. The mean diffusivity, fractional anisotropy (FA), and fiber angle (with respect to the magnet z-axis) were measured in different muscles, and fibers were tracked from several regions of interest (ROIs). RESULTS: The fiber orientations in the current DTI studies agree well with those determined in previous spectroscopic studies. The orientation angles ranged from 13.4 degrees in the lateral gastrocnemius to 48.5 degrees in the medial soleus. The diffusion ellipsoid in muscle tissue is anisotropic and approximates a prolate model, as shown by color maps of the anisotropy. Fibers were tracked from the different muscle regions, and the unipennate and bipennate structure of muscle fibers was visualized. CONCLUSION: The study clearly shows that in vivo fiber tracking of muscle fibers is feasible and could potentially be applied to study muscle structure function relationships.     

Fractional anisotropy values of calf muscles in normative state after exercise: preliminary results

PURPOSE: We measured fractional anisotropy (FA) of calf muscles from diffusion tensor (DT) images from simultaneous scanning of bilateral calves and determined changes in values after unilateral exercise loading. METHOD: We obtained DT images of both calves of 10 healthy male volunteers and measured FA of the anterior tibialis, gastrocnemius, and soleus muscles. Two of the ten were subjected to loaded exercise in their right calves; we recorded FA values immediately after exercise and 24 hours, 72 hours, and 1 week later. RESULTS: At rest, the mean FA values of the 20 calves were 0.63+/-0.02 in the anterior tibialis, 0.56+/-0.05 in the gastrocnemius, and 0.57+/-0.04 in the soleus muscles. The differences were statistically significant (P<0.001) by analysis of variance (ANOVA), and differences between anterior tibialis and gastrocnemius (corrected P<0.01) and anterior tibialis and soleus (corrected P<0.01) muscles were significant by Bonferroni post hoc test. The FA values of the exercise-loaded soleus and gastrocnemius muscles of the 2 volunteers decreased just after exercise but gradually recovered to the baseline after one week. CONCLUSION: Our method may be useful for assessing minimal muscle damage related to muscle fatigue.     

Assessment of calf muscle contraction by diffusion tensor imaging

The goal of this study was to assess the changes of water diffusion during contraction and elongation of calf muscles using diffusion tensor (DT) MRI in normal volunteers. Twenty volunteers (mean age, 29 +/- 4 years) underwent DT MRI examination of the right calf. Echo planar imaging sequence was performed at rest, during dorsal flexion and during plantar flexion. The three eigenvalues (lambda1, lambda2, and lambda3), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of the diffusion tensor were calculated for medial gastrocnemius (mGM) and tibialis anterior (TA). A fiber tractography was performed on both muscles. Non-parametric Wilcoxon and Mann Whitney tests were used for statistical evaluation. At rest, lambda1, lambda2 and ADC of mGM were higher than their counterparts of TA (P < 0.01). During dorsal flexion, the three eigenvalues and ADC of TA significantly increased (P < 0.05) as their counterparts of mGM slightly decreased (P=NS). Opposite variations were detected during plantar flexion of the foot. Visual analysis evidenced a relationship between 3D representations of MRI fibers and physiological state of muscles. Contraction of calf muscles produces changes in DT parameters, which are related to the physiological state of the muscle.     

儿童注意力缺陷多动障碍放射冠前区的扩散张量成像研究

目的运用扩散张量成像(DTI)研究儿童注意力缺陷多动障碍(PADHD)患者大脑额叶放射冠前区(ACR)的异常改变。资料与方法 11例PADHD患者和11名年龄、性别和智商匹配的健康者通过Philips 1.5 TIntera Achieva磁共振扫描仪行DTI,后处理获得部分各向异性指数(FA)和表观扩散系数(ADC)图。分别于5个额叶层面:前联合、前联合上6、12、18和24 mm的双侧ACR选取6个感兴趣区。比较两组不同层面感兴趣区的上述DTI参数值。结果单因素方差分析显示PADHD患者额叶不同层面上ACR的FA值和ADC值均未见明显统计学差异(P>0.05);与正常对照组相比,ACR的FA值(F=47.13,P<0.01)和ADC值(F=113.25,P<0.01)则明显不同。结论 DTI能够显示PADHD患者ACR异常。FA降低和ADC增高可能源于其结构和完整性的丧失。     

Shortened T2 after exercise in ischemic skeletal muscle

PURPOSE: To detect skeletal muscle ischemia with transverse relaxometry after ischemic exercise. MATERIALS AND METHODS: Ten subjects with intermittent claudication were studied. T2 was measured in the gastrocnemius and soleus muscles (m. gastrocnemius and m. soleus) at rest and repeatedly after exercise during 45 minutes of recovery. Prior to MRI a symptom-limited treadmill exercise was performed, and the ankle-arm blood pressure index (AAI) was measured at rest and after exercise. RESULTS: In the 14 legs with ischemic pain, a diverging response was found in the calf: T2 increased in m. gastrocnemius by 5.6% +/- 4.9%, but decreased in m. soleus by -1.2% +/- 4.4% (P < 0.001). Moreover, 13 regions in legs with ischemic pain and reduced AAI (from 0.7 +/- 0.2 at rest to 0.31 +/- 0.15 after exercise) had shortened T2 (-3.6% +/- 1.8%) immediately after exercise. This finding was most frequent in m. soleus and two regions of m. gastrocnemius. Recovery was delayed in the latter two regions. CONCLUSION: T2 may identify ischemic muscles after hypoxic exercise. Shortened T2 suggests a reduced water content (e.g., distribution volume of water) and may affect the upslope kinetics of an extravascular perfusion tracer. The different responses to ischemia by the soleus and gastrocnemius muscle may be due in part to their different fiber type compositions.     

创伤性脑白质损伤的扩散张量成像研究

目的:评价扩散张量成像(DTI)在创伤性脑白质损伤(WMI)中的应用价值。方法:16例创伤性脑外伤后经临床诊断有WMI的患者通过Philips 1.5TIntera Achieva MR扫描仪行常规MRI和DTI。后处理获得部分各向异性指数(FA)、表观弥散系数(ADC)和纤维示踪成像三维图。根据T2WI及T2快速场回波图像,分别于WMI区域、同侧同名或对侧同名纤维束正常区域取感兴趣区,测量FA值和ADC值并进行比较。结果:脑外伤患者损伤脑白质中挫伤和出血、仅挫伤和仅出血区域三者之间的FA值(F=0.68,P>0.05)和ADC值(F=0.53,P>0.05)均未见明显不同。除仅出血区域的ADC值与对照区域相比差异无统计学意义(t=1.36,P>0.05),挫伤和出血(t=9.72,P<0.05)、仅挫伤(t=8.28,P<0.05)和仅出血(t=5.44,P<0.05)区域的FA值较正常对照区域明显降低,挫伤和出血(t=4.71,P<0.05)、仅挫伤(t=4.81,P<0.05)的ADC值较正常对照明显增高,纤维示踪成像显示损伤区域脑白质较正常区域稀疏、分离、缺失。结论:DTI技术能够显示患者WMI区域的异常改变,但ADC值对出血的判断有局限性。     

Reproducibility analysis of diffusion tensor indices and fiber architecture of human calf muscles in vivo at 1.5 Tesla in neutral and plantarflexed ankle positions at rest

Purpose:

To investigate the reproducibility of diffusion tensor imaging (DTI) ‐derived indices and fiber architecture of calf muscles at 1.5 Tesla (T), to establish an imaging based method to confirm ankle position, and to compare fiber architecture at different ankle positions.

Materials and Methods:

Six subjects were imaged at 1.5T with the foot in neutral and plantarflexed positions. DTI indices were calculated in four muscle compartments (medial and lateral gastrocnemius [MG, LG], superficial and deep anterior tibialis [AT‐S, AT‐D]). Two subjects were scanned on 3 days to calculate the coefficient of variability (CV) and the repeatability coefficient (RC).

Results:

DTI indices were close to the values obtained in earlier 3T and 1.5T studies. Fractional anisotropy decreased significantly in the MG and increased significantly in the AT‐S and AT‐D compartments while fiber orientation with respect to the magnet Z‐axis increased significantly in the MG and decreased significantly in the AT‐S compartment with plantarflexion. The CV and RC for the DTI indices and fiber orientations were comparable to 3T studies. Fiber lengths and orientation angles in the MG matched corresponding measures from ultrasound studies.

Conclusion:

DTI at 1.5T provides reproducible measures of diffusion indices and fiber architecture of calf muscle at different muscle lengths. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

白血病脑实质浸润的弥散张量成像应用研究

目的探讨1．5T磁共振弥散张量成像（diffusiontensorimaging,DTI）,部分各向异性（fractionalanisotropy,FA）和表观扩散系数（apparentdiffusioncoefficient,ADC）及弥散张量纤维束成像（diffusiontensortractography,DTT）在成人白血病脑实质浸润的应用价值。方法回顾性分析经临床证实的8例白血病脑实质浸润病例DTI之ADC、FA参数图,分别测量病变、水肿及健侧相应部位FA值和ADC值;观察各例在DTT图的变化。结果白血病脑实质浸润的肿瘤实质部分FA值8例全部较健侧降低,ADC值5例减低,3例增高;周围水肿区FA值全部降低,ADC值全部增高;脑白质纤维束DTT显示有中断、移位、浸润。结论DTI对脑侵犯神经纤维束损伤具有独特诊断价值;DTI的参数变化能够量化神经纤维受压后微细结构的变化,DTT图像重建能直观显示脑白质纤维束的完整性及损伤程度,DTI联合DTT可更加准确地评估白血病脑侵犯的损害程度。     

正常成人大脑白质纤维磁共振弥散张量成像的定量研究

目的:运用弥散张量成像(DTI)定量研究正常成人脑白质不同解剖部位的各向异性特点.方法:对60名正常成人按年龄分成四组,均行DTI检查,分析其表面弥散系数(ADC)图及各向异性分数(FA)图的特点,并对不同解剖部位的脑白质进行ADC值及FA值的定量分析,通过统计学分析得出其弥散系数和各向异性特点.结果:不同年龄组间相同解剖部位脑白质ADC值及FA值的差异无统计学意义;不同解剖部位间FA值及ADC值的差异具有显著性.结论:DTI可清晰显示脑内白质的走行及方向,FA能准确定量分析正常成人不同部位脑白质纤维的各向异性程度.     

复发-缓解型多发性硬化投射纤维束定量DTI

目的：探讨复发-缓解型多发性硬化（RRMS）患者投射纤维定量扩散张量改变.方法：20例RRMS患者及年龄和性别相匹配的20例健康志愿者（对照组）行MRI扫描,获取常规MRI及DTI图像,分别进行测量分析,比较2组投射纤维的部分各向异性指数（FA）和平均扩散系数（MD）值的变化.主要纤维束包括丘脑前辐射（atr）、丘脑上辐射（str）、丘脑后辐射（ptr）、皮质延髓束（cpt）、皮质脊髓束（cst）等.结果：RRMS组患者与健康对照组的FA值比较：ptr（左侧：0.541±0.141 vs 0.628±0.153;右侧：0.512±0.079 vs 0.560±0.102）、cpt/atr（左侧：0.421±0.118 vs 0.503±0.104;右侧：0.437±0.064 vs 0.512±0.102）、cpt/ptr（左侧：0.405±0.056 vs 0.500±0.078;右侧：0.427±0.057 vs 0.496±0.083）、cpt/cst/str（左侧：0.476±0.115 vs 0.554±0.056;右侧：0.462±0.095 vs 0.520±0.074）,RRMS组的FA值均较健康对照组低,2组间差异有统计学意义（P〈0.05）;RRMS组患者atr的FA值（左侧：0.538±0.103,右侧：0.542±0.092）与对照组（左侧：0.564±0.087;右侧0.568±0.116）比较,差异无统计学意义（P〉0.05）.RRMS组患者与健康对照组的MD值比较：cpt/ptr（左侧：0.928±0.102 vs 0.853±0.105;右侧：0.949±0.165 vs 0.859±0.141）、cpt/cst/str（左侧：0.811±0.137 vs 0.772±0.093;右侧：0.868±0.167 vs 0.784±0.128）的MD值差异有统计学意义（P〈0.05）,RRMS组的MD值较健康对照组增高;RRMS组患者atr（左侧：0.898±0.143 vs 0.868±0.118;右侧：0.850±0.164 vs0.835±0.074）、ptr（左侧：0.874±0.203 vs 0.829±0.103;右侧：0.847±0.172 vs 0.802±0.075）、cpt/atr（左侧：0.856±0.187 vs 0.805±0.161;右侧：0.829±0.246 vs 0.820±0.093）的MD值和健康对照比较差异均无统计学意义（P〉0.05）.结论：多发性硬化患者双侧ptr、cpt/atr、cpt/ptr、cpt/cst/str存在FA值减小,双侧cpt/ptr、cpt/cst/str存在MD值的增高,提示在投射纤维中上述白质纤维束存在结构改变,DTI可以作为反映RRMS投射纤维微观病理改变的敏感检查指标.     

Diffusion tensor eigenvector directional color imaging patterns in the evaluation of cerebral white matter tracts altered by tumor

PURPOSE: To categorize the varied appearances of tumor-altered white matter (WM) tracts on diffusion tensor eigenvector directional color maps. MATERIALS AND METHODS: Diffusion tensor imaging (DTI) was obtained preoperatively in 13 patients with brain tumors ranging from benign to high-grade malignant, including primary and metastatic lesions, and maps of apparent diffusion coefficient (ADC), fractional anisotropy (FA), and major eigenvector direction were generated. Regions of interest (ROIs) were drawn within identifiable WM tracts affected by tumor, avoiding grossly cystic and necrotic regions, known fiber crossings, and gray matter. Patterns of WM tract alteration were categorized on the basis of qualitative analysis of directional color maps and correlation analysis of ADC and FA. RESULTS: Four basic patterns of WM alteration were identified: 1) normal or nearly normal FA and ADC, with abnormal tract location or tensor directions attributable to bulk mass displacement, 2) moderately decreased FA and increased ADC with normal tract locations and tensor directions, 3) moderately decreased FA and increased ADC with abnormal tensor directions, and 4) near isotropy. FA and ADC were inversely correlated for Patterns 1-3 but did not discriminate edema from infiltrating tumor. However, in the absence of mass displacement, infiltrating tumor was found to produce tensor directional changes that were not observed with vasogenic edema, suggesting the possibility of discrimination on the basis of directional statistics. CONCLUSION: Tumor alteration of WM tracts tends to produce one of four patterns on FA and directional color maps. Clinical application of these patterns must await further study.     

DTI在正常前列腺的应用研究

目的探讨1.5 T MR扩散张量成像(diffusion tensor imaging,DTI)在正常前列腺的参数特点及纤维示踪图像(fiber tracking,FT)表现,为DTI在前列腺癌的应用提供研究基础。资料与方法 21名健康男性志愿者[(24.7±3.59)岁]行前列腺常规MRI及DTI扫描,将DTI扫描数据行后处理分析,测量中央叶和外围叶感兴趣区的表观扩散系数(ADC)和各向异性分数(FA),比较两者的ADC、FA值差异有无统计学意义,并重建前列腺的FT图像。结果 (1)健康男性前列腺DTI左右两侧中央叶和外围叶的ADC、FA值差异均无统计学意义(P>0.05);(2)中央叶和外围叶的ADC、FA值差异有统计学意义,中央叶的ADC值低于外围叶,中央叶的FA值高于外围叶(P<0.05);(3)FT图显示不同颜色的纤维对应不同走行方向,且中央叶的纤维排列比外围叶紧密。结论 1.5 TMR DTI在正常前列腺研究中具有可行性,有助于DTI在前列腺癌中的应用研究。     

偏头痛患者磁共振弥散张量成像的初步探讨

 目的探讨偏头痛患者磁共振弥散张量中脑白质损害。方法对17例偏头痛患者和16名健康志愿者,进行磁共振弥散张量成像(diffusiontensorimaging,DTI)检查。分别测定两组受试者的双侧额叶皮层下白质、双侧侧脑室旁周围白质和双侧枕叶皮层下白质中感兴趣区(regionofinterests,ROIs)的“看似正常的白质”(normalappearingwhitematter,NAWM)表观扩散系数(apparentdiffusioncoefficient,ADC)和各向异性分数(fractionalanisotropy,FA),对两组数据进行比较分析。结果偏头痛组双侧侧脑室旁周围白质ADC值较对照组明显增高(P<0.05),双侧枕叶皮层下白质各向FA值较对照组明显降低(P<0.01)。结论DTI有助于早期发现偏头痛患者的脑白质损害。     

正常青年人群脑磁共振扩散张量成像的定量研究

目的:运用扩散张量成像(DTI)方法研究正常青年人群不同脑组织及解剖部位的各向异性特点.方法:对40名正常青年人群行DTI成像,分析其表面扩散系数(ADC)图及各向异性分数(FA)图的特点,并对不同脑组织进行ADC及FA值的定量分析,通过统计学分析得出其扩散和各向异性特点.结果:扩散系数ADC不能区分脑灰质与脑白质(ADC分别为807.78±90.29,775.79±115.31×10-6mm2/s,P=0.098).而脑脊液、脑灰质与脑白质间的FA值间差异均具有显著性意义(P<0.05).不同解剖部位的脑白质间具有显著不同的各向异性(P<0.05).胼胝体压部的各向异性程度最高(0.73±0.09),其次为胼胝体膝部与内囊后肢(0.68±0.05,0.67±0.06),半卵圆中心与枕钳最低(0.53±0.09,0.53±0.09).脑灰质中以背侧丘脑具有最高的各向异性(0.31±0.04).结论:FA可准确定量正常青年人群不同脑组织的扩散特点,DTI可清晰显示脑内白质的方向及走行.     

3.0T MR DTI及DTT对正常青年人腕管内正中神经的定量分析

目的 运用扩散张量成像(DTI)定量分析健康青年人腕管内正中神经(MN)部分功能参数值特点及扩散张量纤维束成像(DTT)重建MN纤维束.方法 采用3.0T MR对25名健康志愿者行腕部常规MR及DTI序列扫描,测量DTI各参数值并重建MN纤维束.结果 ①MN各向异性分数(FA)值=0.686±0.089、MN轴向扩散系数(AD)值=(2.085±0.263)mm2/s、MN径向扩散系数(RD)值=(0.568±0.151)mm2/s、MN平均扩散率(ADC)值=(1.073±0.140)mm2/s.②各层面FA、RD值之间存在显著差异(P<0.05),各层面AD、ADC及各本征值E1、E2、E3之间差异无统计学意义(P>0.05).③腕管内MN从近心端到远心端DTI各部分功能参数均有不同的变化趋势.④MN FA、MN AD、MN RD、MN ADC的95%置信区间上下限分别为(0.675,0.698)、(2.052,2.117)、(0.549,0.587)、(1.056,1.091).⑤利用DTT可以完整地重建显示MN纤维束,远端分支亦能显示.结论 应用DTI及DTT技术可以定量描述MN的FA及直观显示重建的MN纤维束,可为诊断MN病变提供定量的观察指标.     

Hyperbaric oxygen increases the contractile function of regenerating rat slow muscles

Human trials of hyperbaric oxygen (HBO) treatment of sports-related muscle injuries are equivocal. Although most human skeletal muscles are composed of mixed muscle fiber types, it is unclear whether HBO affects fiber types differently. PURPOSE: We tested the hypothesis that HBO can enhance the functional properties of regenerating rat soleus muscles that are composed predominantly of slow fibers. METHODS: After intramuscular injection of bupivacaine hydrochloride to induce the degeneration of all fibers within the soleus muscle, treated rats received daily HBO treatment at 3 atmospheres absolute. RESULTS: In untreated rats, injured muscles demonstrated a reduced force-producing capacity (control soleus vs injured soleus, 220.3 +/- 2.5 vs 157.6 +/- 3.3 kN.m(-2) at 25 d postinjury, respectively, P < 0.05) and contained smaller regenerating muscle fibers than uninjured soleus muscles (fiber cross sectional area in control soleus vs injured soleus, 2289 +/- 164 vs 1154 +/- 92 microm 2 at 25 d postinjury, respectively, P < 0.05). The regenerating soleus muscles of HBO-treated rats demonstrated a greater force-producing capacity as a percentage of contralateral control muscles than the regenerating muscles from untreated rats at 14 d postinjury (regenerating HBO-soleus peak tension and untreated soleus peak tension, 42.9 +/- 1.9 and 35.8 +/- 3.9% of contralateral control muscles, respectively, P < 0.05), but no effect of treatment was observed at 25 d postinjury. CONCLUSION: HBO enhanced the contractile properties of regenerating rat soleus muscles after myotoxic injury, but this improvement was not sustained for the duration of the regenerative process. The data indicate that the outcome of HBO treatment of a muscle injury may be influenced by the fiber type composition of the injured muscle.     

Determination of mouse skeletal muscle architecture using three-dimensional diffusion tensor imaging.

Muscle architecture is the main determinant of the mechanical behavior of skeletal muscles. This study explored the feasibility of diffusion tensor imaging (DTI) and fiber tracking to noninvasively determine the in vivo three-dimensional (3D) architecture of skeletal muscle in mouse hind leg. In six mice, the hindlimb was imaged with a diffusion-weighted (DW) 3D fast spin-echo (FSE) sequence followed by the acquisition of an exercise-induced, T(2)-enhanced data set. The data showed the expected fiber organization, from which the physiological cross-sectional area (PCSA), fiber length, and pennation angle for the tibialis anterior (TA) were obtained. The values of these parameters ranged from 5.4-9.1 mm(2), 5.8-7.8 mm, and 21-24 degrees , respectively, which is in agreement with values obtained previously with the use of invasive methods. This study shows that 3D DT acquisition and fiber tracking is feasible for the skeletal muscle of mice, and thus enables the quantitative determination of muscle architecture.     

Altered diffusion tensor in multiple sclerosis normal-appearing brain tissue: cortical diffusion changes seem related to clinical deterioration

PURPOSE: To investigate normal-appearing white (NAWM) and cortical gray (NAGM) matter separately in multiple sclerosis (MS) in vivo using diffusion tensor imaging (DTI). MATERIALS AND METHODS: In 64 MS patients (12 primary progressive [PP], 38 relapsing remitting [RR], 14 secondary progressive [SP]) and 20 healthy controls, whole-brain apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps were acquired. A stimulated echo acquisition mode (STEAM) DTI sequence was used with minimal geometrical distortion in comparison to echo-planar imaging (EPI). NAWM and NAGM were identified using conventional magnetic resonance (MR) images, allowing a cautious assessment of FA in cortex. RESULTS: Histogram analyses showed significant global FA decreases and ADC increases in MS NAWM compared to control WM. MS cortical NAGM had no significant global ADC increase, but FA was decreased significantly. In regional analyses, nearly all NAWM regions-of-interest (ROIs) had significantly increased ADC compared to controls, but FA was not changed. In nearly all cortical NAGM ROIs, ADC was significantly increased and FA significantly reduced. In multiple linear regression analyses in RR/SPMS patients, NAGM-ADC histogram peak height was associated more strongly with clinical disability than T2 lesion load. CONCLUSION: Tissue damage occurs in both NAWM and cortical NAGM. The cortical damage appears to have more clinical impact than T2 lesions.     

磁共振肌纤维束成像在肌骨系统肿瘤诊断中的应用

目的 探讨扩散张量成像(DTI)及磁共振肌纤维束成像应用于骨肌系统肿瘤诊断的可行性及价值.资料与方法 38例骨肌系统肿瘤,均行常规MRI和DTI,计算并分析良、恶性肿瘤中心区、肿瘤周边区及邻近正常肌肉的部分各向异性值(FA)和体积比各向异性值(VrA),重组病变周围肌纤维束成像,并将MRI表现与手术病理学检查结果作对照研究.结果 良性肿瘤病变周围肌肉肌纤维束成像主要表现为肌肉推移征象.恶性肿瘤主要表现为浸润、破坏征象.良、恶性肿瘤周边区的FA值和VrA值相比差异均有统计学意义(P<0.01),良、恶性肿瘤中心区FA值和VrA值相比差异无统计学意义.结论 MR DTI能用于评价肌骨系统肿瘤的内部结构特征及与周围组织的关系,对良、恶性肌骨系统肿瘤的诊断及鉴别诊断有一定帮助.     

In vivo MR tractography of thigh muscles using diffusion imaging: initial results

The aims of this preliminary study were (1) to demonstrate the feasibility of providing in vivo 3D architecture of human thigh muscles using tractography on a 1.5T magnet, and (2) to assess the value of tractography images to obtain averaged microstructural parameters, i.e., the fractional anisotropy (FA) and the mean apparent diffusion coefficient (ADC), over the whole thigh. Five healthy volunteers were included in this study. Their right thighs were imaged using diffusion tensor imaging and gradient-echo T2* sequences. Muscular tractography was performed on each muscle. MR tractography provided a good approach of the muscle shape and of the orientation of the muscle fibers. There was no aberration in the color-encoding scheme nor in the luminosity assigned to each fiber. In contrast, tendons were not drawn in any of the muscles studied. FA values ranged from 0.27 to 0.38. Mean ADC values ranged from 0.76 to 0.96 × 10⁻³ mm²/s. Our study demonstrated the feasibility of providing in vivo 3D architecture of human thigh muscles using tractography on a 1.5T magnet, and of determining muscular microstructural parameters (FA and ADC). Musculoskeletal radiologists should be aware of these new developments that may provide complementary information on muscles to the usual sequences.