磁共振扩散加权成像预测与评价宫颈癌放化疗疗效的研究

目的 探讨磁共振扩散加权成像(DWI)在预测与评价宫颈癌放化疗疗效中的应用价值.方法 收集282例经病理检查证实为宫颈癌的患者,分别在治疗前、治疗结束后行DWI检查,测量肿瘤最大径和表现扩散系数(ADC)值.治疗结束后,依据实体肿瘤疗效评价标准(RECIST)将患者分为缓解组、无效组.根据治疗结束后2年的随访复查情况将患者分为复发组、无复发组.比较两组间的治疗前和治疗结束后ADC值,并分析疗效及复发情况与治疗前ADC值、治疗结束后的ADC升高值之间的相关性. 结果 缓解组223例,无效组59例.复发组70例,无复发组212例.缓解组治疗前ADC值明显低于无效组(t=3.274,P<0.05),无复发组治疗前ADC值明显低于复发组(t=1.031,P<0.05).治疗前ADC值低的患者复发率明显低于治疗前ADC值高的患者(χ²=5.175,P<0.05).治疗结束后的疗效及治疗结束后2年的复发情况与治疗前ADC值均呈负相关(r=-0.571、-0.675,P<0.05),与治疗结束后的ADC升高值均呈正相关(r=0.641、0.547,P<0.05).缓解组、无复发组治疗结束后ADC值升高明显(t=2.031、4.011,P<0.05),无效组、复发组ADC值升高不明显.结论 治疗前的ADC值有助于预测宫颈癌放化疗疗效,治疗结束后的ADC变化值有助于评价宫颈癌放化疗疗效.     

直肠癌调强放疗中固定铅门技术和分野技术的剂量学比较

目的 研究直肠癌患者应用固定铅门技术(FJT)和分野技术(SFT),分析比较2种不同的调强放疗技术的剂量学差异。方法 选择15例直肠癌患者,进行CT模拟定位,勾画靶区及危及器官,对同一CT图像设计FJT计划和SFT计划。评估靶区及危及器官的剂量分布。结果 FJT计划组PTV₉₅覆盖度降低(t=-2.24,P<0.05);D_mean升高(t=2.54,P<0.05);HI较差(t=3.09,P<0.05),CI无差异。小肠V₅升高(t=4.76,P<0.05),骨髓V₂₀和V₅₀优于SFT计划组(t=-2.66、-3.36,P<0.05),而D_max高于SFT计划组(t=3.30,P<0.05);全身的V₂₀高于SFT计划组(t=2.48,P<0.05)。MU的数量和子野数量明显低于SFT计划组(t=-9.38、-6.46,P<0.05),计划验证通过率优于SFT计划组(t=10.46,P<0.05);治疗时间由原来的平均12 min缩短至6 min,缩短50%。结论 与SFT技术比较,直肠癌患者采用FJT技术,其靶区、危及器官受量均能满足临床治疗要求。患者治疗时间缩短,MU数量降低,单位时间内每天每台机器治疗患者的数量增加,减少患者的等待时间,降低加速器质量保证的难度。     

妇科肿瘤后装逆向调强放疗的初步临床研究

目的 评价后装逆向调强放疗技术在妇科肿瘤治疗中的临床价值。方法 选取20例Ⅰ~Ⅲ期宫颈癌患者,采用随机数字表和余数分组的方法分为A、B两组,各10例。A组病例行后装逆向调强放疗,B组病例行三维适形后装放疗。分析两组患者的靶区剂量分布、危及器官受量、放疗并发症及近期疗效。 结果 A组靶区剂量均匀度指数（HI）为52.43±0.45,好于B组的46.37±1.45（t=0.92,P<0.05）;A组直肠、膀胱最大受量D_max分别比B组低37%、35%（t=1.34、1.39,P<0.05）,A组75%处方剂量的直肠、膀胱受照体积V₇₅约为B组的1/2（t=1.23、1.13,P<0.05）;A组局部控制率96%好于B组的 93%（t=1.25,P<0.05）。结论 后装逆向调强放疗优于三维适形后装放疗,值得在妇科肿瘤治疗中广泛应用。     

姜黄素提高人胰腺癌PANC-1细胞放射敏感性的机制研究

目的 观察姜黄素对人胰腺癌PANC-1细胞放射敏感性的影响。方法 γ射线照射人胰腺癌PANC-1细胞,同时联合应用姜黄素处理细胞,通过MTT法检测PANC-1细胞增殖活性的变化,利用流式细胞仪观察PANC-1细胞周期和凋亡率的变化,采用RT-PCR和Western blot分析PANC-1细胞中P21表达的变化。结果 与γ射线照射组比较,γ射线联合应用姜黄素可以显著降低PANC-1细胞的增殖活性(t=6.72, P<0.01),同时影响细胞周期的变化,显著增加S期细胞(t=4.78, P<0.05),PANC-1细胞凋亡明显提高(t=6.58,P<0.01),并伴有P21蛋白和mRNA表达的变化(t=5.72、5.63, P<0.01)。结论 姜黄素可以显著提高人胰腺癌PANC-1细胞的放疗敏感性,这一特性与P21的表达有关。     

大蒜素提高人胰腺癌BXPC3细胞放射敏感性的机制研究

目的：观察大蒜素对人胰腺癌BXPC3细胞的生长及放射敏感性的影响。方法：大蒜素联合X射线处理胰腺癌BXPC3细胞,采用MTT法检测细胞的生长和增殖;细胞流式技术测定细胞周期改变以及细胞凋亡;细胞克隆形成法观察大蒜素对辐射的增敏作用。采用RT-PCR、Western blot分析细胞中Bax、Bcl-2表达变化。结果：12、24和48 h大蒜素处理导致细胞生长抑制的半数抑制浓度（IC₅₀）分别为76.24、58.34和 43.58 μmol/L。与单纯照射组相比,照射联合应用大蒜素明显抑制胰腺癌细胞的生长（t=2.74,P<0.05）,影响细胞周期的变化,显著增加G₂/M期细胞阻滞（t=11.41,P<0.05）;细胞凋亡率明显提高（t=12.36,P<0.05）,伴有Bax表达的增高（t=4.83,P<0.05）和Bcl-2的表达下调（t=3.69,P<0.05）。 结论：大蒜素可以通过诱导细胞周期阻滞及细胞凋亡而抑制胰腺癌BXPC3细胞的生长,具有放射增敏作用,凋亡相关因子Bax、Bcl-2参与了这一过程。     

晚期非小细胞肺癌患者放疗前后肿瘤标志物变化与近期疗效的临床分析

目的 回顾性研究晚期非小细胞肺癌患者放疗前后血清CEA、CYFAR21-1、SCC、CA125的水平变化,探讨血清肿瘤标志物的改变及与放疗近期疗效的关系。方法 常规检查205例经确诊的晚期非小细胞肺癌患者放疗前、后血清CEA、CYFAR21-1、SCC、CA125等肿瘤标志物的水平(应用电化学发光法), 同时评估放疗的近期疗效,分析肿瘤标志物的变化及与近期疗效的关系。结果 205例患者放疗后近期有效113例,总有效率为55.1%。此113例患者放疗后血清CEA、CYFAR21-1、SCC、CA125水平均较放疗前发生了明显下降(t=3.224, 2.896, 3.137, 3.219, P<0.05),其中Ⅲ期及Ⅳ期患者血清肿瘤标志物CEA、CYFAR21-1、SCC、CA125放疗后与放疗前比较,差异均有统计学意义(Ⅲ期:t=2.484, 2.445, 2.148, 2.109, P<0.05;Ⅳ期:t=2.072, 2.857, 2.277, 2.436, P<0.05);而放疗后近期非有效的92例患者中,放疗后血清肿瘤标志物较放疗前明显上升(t=2.224, 2.005, 2.261, 2.545, P<0.05)。放疗后肿瘤标志物降低组的近期疗效明显好于肿瘤标志物升高组,差异有统计学意义(χ²=80.001, P<0.01)结论 血清肿瘤标志物CEA、CYFAR21-1、SCC、CA125水平或可用于晚期非小细胞肺癌患者放疗后的近期疗效评估。     

多次低剂量照射对雄性糖尿病大鼠脾细胞凋亡和免疫因子的影响

目的 观察多次低剂量辐射(LDR)对糖尿病(DM)大鼠脾细胞凋亡和免疫因子的影响。方法 大鼠随机分为对照组、DM组和DM+LDR组;剂量分别为25、50和75 mGy,共照射15次;照射后4周,采用流式细胞术检测脾细胞凋亡和TCRα β百分数的变化,酶联免疫吸附法(ELISA)检测血清和脾细胞培养上清IL-2含量的变化。结果 与对照组相比,DM和DM + LDR两组大鼠体重均下降,尤以DM组明显。DM+LDR组大鼠血糖水平虽明显高于对照组(t₂₅=23.321、 t₅₀=18.329、 t₇₅=9.23,P<0.01),但显著低于DM组(t₂₅=3.574、 t₅₀=4.593、 t₇₅=5.577,P< 0.01)。同时发现:与对照组相比,DM+LDR各组脾细胞凋亡增加,其中DM+50 mGy组增加明显(t₅₀=4.102,P<0.01)。血清IL-2含量也增加,但是差异均无统计学意义。脾细胞培养上清IL-2含量明显下降(t₂₅=7.778、 t₅₀=7.411、 t₇₅=8.325,P<0.01)。与DM组相比,DM+LDR各组脾细胞凋亡和TCRα β百分数均明显降低(凋亡:t₂₅=4.772、 t₅₀=3.346、 t₇₅=6.778;TCRα β:t₂₅=3.381、 t₅₀=5.807、 t₇₅=2.356,P<0.05～P<0.01)。血清IL-2含量呈下降趋势;脾细胞培养上清IL-2含量均有升高趋势。结论 多次LDR能够削弱糖尿病造成的大鼠体重减轻和血糖升高,降低糖尿病所致的脾细胞凋亡,并能调节脾脏免疫因子,改善其失衡状态。     

和厚朴酚对鼻咽癌细胞生长及其放射敏感性的影响

目的 研究和厚朴酚对人鼻咽癌CNE-1和CNE-2细胞生长和放射敏感性的影响。方法 采用四甲基偶氮唑盐比色法(MTT法)检测CNE-1和CNE-2细胞生长;流式细胞术检测细胞周期变化;磷脂酰丝氨酸外翻分析法检测细胞凋亡;Western blot法测定相关蛋白表达水平;采用细胞克隆形成法观察和厚朴酚对细胞放射敏感性的影响。结果 和厚朴酚明显抑制CNE-1和CNE-2细胞生长,且存在着明显剂量和时间依赖性,半数抑制浓度(IC₅₀)在CNE-1和CNE-2细胞分别为2.84和2.68 μmol/L(24 h),2.50 和2.20 μmol/L(48 h)。2.5 μmol/L和厚朴酚处理24 h后,CNE-1细胞的早期凋亡、晚期凋亡和坏死细胞分别达到24.53%、23.05%和7.13%,与未经处理的对照组之间差异均有统计学意义(t=-41.17、-8.18、-6.08, P<0.05)。4和3 μmol/L的和厚朴酚分别使CNE-1细胞和CNE-2细胞中促凋亡蛋白Bax和凋亡效应蛋白Caspase 3的表达水平出现2.31倍和1.89倍(t=-15.92、-17.15,P<0.05)及4.43倍和1.85倍(t=-29.39、-13.47,P<0.05)的增加,同时抗凋亡蛋白Bcl-2蛋白的表达降低45.05%和36.50%(t=26.94、66.14,P<0.05)。和厚朴酚24 h预处理可以明显提高CNE-1和CNE-2细胞对X射线的放射敏感性,SER分别为1.41和1.88。3 Gy X射线照射明显增加两种细胞的G₂/M期细胞数量(t=-14.96、-19.26, P<0.05),和厚朴酚降低了辐射导致的G₂/M期细胞阻滞(t=7.65、4.98,P<0.05),同时Cyclin B1蛋白表达明显增加(t=-33.07、-73.49,P<0.05)。结论 和厚朴酚诱导人鼻咽癌CNE-1和CNE-2细胞凋亡和细胞坏死而导致细胞生长的抑制。干预X射线诱导G₂/M期细胞阻滞可能是和厚朴酚预处理提高两种鼻咽癌细胞放射敏感性的重要作用机制。     

下颌骨CT扫描的优化

目的 通过改变扫描位置优化下颌骨CT扫描方法降低辐射剂量.方法 50例下颌骨CT扫描的连续病例纳入本前瞻性对照研究,用随机数字表法分2组,各25例.分别进行体位优化法和常规法扫描,比较其图像质量、CT 剂量加权指数(CTDI_vol)、扫描范围长度(L)及剂量长度乘积(DLP).结果 体位优化法与常规法的下颌骨图像质量相同,两组的CTDI_vol 无明显差异,体位优化法扫描范围长度(L)和剂量长度乘积(DLP) 比常规法分别下降20%(t=4.986, P<0.05) 和16%(t=3.682, P<0.05),并避开了晶状体.结论 体位优化法下颌骨扫描能有效减少扫描长度和避开晶状体,降低有效辐射剂量.     

早期结外鼻腔NK/T细胞淋巴瘤固定野调强和旋转调强放疗的剂量学比较

目的 探讨早期结外鼻腔NK/T细胞淋巴瘤固定野调强和旋转调强放疗的剂量学和执行效率差异。 方法 选取10例I_E ~Ⅱ_E期鼻腔NK/T细胞淋巴瘤患者,分别设计共面5野（5F）、共面9野（9F）、非共面5野（5F-N）和旋转调强（RapidArc）方案,以5F计划为参照,9F、5F-N和RapidArc计划分别与其就靶区适形度指数（CI）、均匀性指数（HI）和危及器官的受照剂量进行比较,同时比较各计划剂量验证通过率、出束跳数和治疗时间。 结果 CI值9F（0.478±0.181）、5F-N（0.465±0.121）、RapidArc（0.518±0.111）与5F（0.419±0.159）计划相比,差异无统计学意义;HI值9F（0.111±0.027）、RapidArc（0.112±0.031）显著低于5F计划的（0.136±0.038）（t=3.11、3.04,P<0.05）。9F计划晶状体D_max显著高于5F计划（健侧t=2.82,P<0.05;患侧t=3.25,P<0.05）。5F-N计划视神经D_max显著低于5F计划（健侧t=4.27,P<0.05;患侧t=2.82,P<0.05）。RapidArc计划健侧晶状体（t=3.25,P<0.05）、眼球（t=3.25,P<0.05）和视神经（t=2.57,P<0.05）D_max显著低于5F计划。此外,RapidArc计划视交叉D_max显著低于5F计划（t=7.62,P<0.05）。各计划执行效率为RapidArc >5F >5F-N >9F。结论 在剂量学和计划执行效率方面,RapidArc较共面固定野5野调强更具优势,推荐作为早期结外鼻腔NK/T细胞淋巴瘤调强放疗布野模式首选。     

Longitudinal changes in gray matter regions after cranial radiation and comparative analysis with whole body radiation: a DTI study

Purpose: Radiation-induced white matter changes are well known and vastly studied. However, radiation-induced gray matter alterations are still a research question. In the present study, these changes were assessed in a longitudinal manner using Diffusion Tensor Imaging (DTI) and further compared for cranial and whole body radiation exposure.

Materials and methods: Male mice (C57BL/6) were irradiated with cranial or whole body radiation followed by DTI study at 7T animal MRI system during predose, subacute and early delayed phases of radiation sickness. Fractional anisotropy (FA) and mean diffusivity (MD) values were obtained from brain’s gray matter regions.

Results: Decreased FA with increased MD was observed prominently in animals exposed to cranial radiation showing most changes at 8 months post irradiation. However, whole body radiation induced FA changes were mostly observed at 1 month post irradiation as compared to controls.

Conclusions: The differential response after whole body and cranial irradiation observed in the study depicts that radiation exposure of 5?Gy could induce permanent alterations in gray matter regions prominently as observed in Caudoputamen region at all the time points. Thus, our study has bolstered the role of DTI to probe microstructural changes in gray matter regions of brain after radiation exposure.     

Distribution of microstructural damage in the brains of professional boxers: a diffusion MRI study

PURPOSE: To investigate and localize cerebral abnormalities in professional boxers with no history of moderate or severe head trauma. MATERIALS AND METHODS: Diffusion tensor imaging (DTI) was used to determine the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in the brains of 81 professional male boxers and 12 male control subjects. Voxel-based analysis (VBA) of both the diffusion and anisotropy values was performed using statistical parametric mapping (SPM). From this objective analysis, regions of microstructural abnormalities in the brains of the boxers were located. RESULTS: Increases in the ADC, and decreases in FA were identified in deep white matter (WM), while decreases in ADC were identified in cortical gray matter (GM). Regions of positive correlation between ADC and age were also found in both the boxer and control groups, although the regions and strength of the correlation were not the same in each group. CONCLUSION: Using VBA, we localized previously unreported abnormalities in the brains of professional boxers. These abnormalities are assumed to reflect cumulative (chronic) brain injury resulting from nonsevere head trauma.     

Magnetic resonance diffusion tensor imaging of the testis: Preliminary observations

IntroductionTo evaluate the feasibility of testis diffusion tensor imaging (DTI), to determine normative apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values and to assess the efficacy of DTI in characterizing testicular pathology.Materials and methodsFifty-six men underwent MRI of the scrotum, including DTI. Parametric and non-parametric statistical tests were used to compare the ADC and FA between the cranial, middle and lower thirds of normal testis and between the bilateral testicular thirds. Comparison between the ADC and FA of normal testis, malignant and benign testicular lesions was performed.ResultsNo significant differences of the ADC and FA in normal testis between the cranial, middle and lower thirds and between the bilateral testicular thirds were found. ADC was significantly lower in malignancies compared to normal testis (P = 0.006) and benign testicular lesions (P = 0.006). FA was significantly higher both in malignancies (P = 0.001) and benign lesions (P < 0.001) compared to normal testis. FA in malignancies did not differ from FA in benign lesions (P = 0.221)ConclusionsThis study shows the feasibility of testis DTI. Both ADC and FA significantly differ between testicular lesions and normal testis, although FA did not show an incremental diagnostic value compared to ADC in lesion differentiation.     

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.     

Quantitative diffusion tensor MR imaging of the brain: field strength related variance of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) scalars

The objectives were to study the “impact” of the magnetic field strength on diffusion tensor imaging (DTI) metrics and also to determine whether magnetic-field-related differences in T2-relaxation times of brain tissue influence DTI measurements. DTI was performed on 12 healthy volunteers at 1.5 and 3.0 Tesla (within 2 h) using identical DTI scan parameters. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured at multiple gray and white matter locations. ADC and FA values were compared and analyzed for statistically significant differences. In addition, DTI measurements were performed at different echo times (TE) for both field strengths. ADC values for gray and white matter were statistically significantly lower at 3.0 Tesla compared with 1.5 Tesla (% change between −1.94% and −9.79%). FA values were statistically significantly higher at 3.0 Tesla compared with 1.5 Tesla (% change between +4.04 and 11.15%). ADC and FA values are not significantly different for TE=91 ms and TE=125 ms. Thus, ADC and FA values vary with the used field strength. Comparative clinical studies using ADC or FA values should consequently compare ADC or FA results with normative ADC or FA values that have been determined for the field strength used.This paper was presented at the 21st Annual Scientific Meeting of the ESMRMB, September 9–12, 2004, Copenhagen, Denmark     

病毒性脑炎扩散张量成像的初步研究

目的:比较病毒性脑炎脑内病灶和对照侧镜像区的扩散特性的差异,探讨扩散张量成像(DTI)在诊断病毒性脑炎中的应用价值。方法:分别对13例病毒性脑炎患者行常规MRI和DTI检查,经处理后分别获得每个层面的表观扩散系数(ADC)图、各向异性(FA)图、1-VR(VR)图和纤维束成像(DTT)图,并对DTI各输出参数ADC、FA、1-VR进行统计分析。结果:13例患者共计20个病灶,病灶区的FA值及1-VR值减低,病灶区与对照侧的FA值及1-VR值间的差异有统计学意义(P<0.01),病灶区与对照侧的ADC值间的差异无统计学意义(P=0.2026,P>0.05)。FA图显示病灶的范围比常规T2WI大。DTT图显示受累白质纤维束是浸润性改变,部分纤维中断。结论:DTI指标可以反映病毒性脑炎病变组织的微观结构变化信息,为常规MRI检查提供补充信息,对其临床诊疗和评估也有一定的价值。     

婴幼儿脑白质发育的弥散张量磁共振成像

目的：应用弥散张量成像分析不同年龄段婴幼儿的不同部位脑白质的各向异性。材料和方法：将26例正常婴幼儿（年龄4d至24个月）分为4组：第一组7例，小于6个月；第二组8例，6—12个月；第三组6例，12—18个月；第四组5例，18—24个月。均进行常规头颅MR和弥散张量成像，并测量不同部位脑白质的FA值和ADC值。结果：随着年龄的增加，ADC值逐渐减低，FA值逐渐升高。不同组别大脑白质各部位的ADC值和FA值不同（P〈0．05）。结论：弥散张量成像可以反映活体脑白质的细微结构，可用于评价脑白质发育情况。     

Diffusion tensor imaging of tract involvement in children with pontine tumors

BACKGROUND AND PURPOSE: Conventional MR imaging permits subcategorization of brain stem tumors by location and focality; however, assessment of white matter tract involvement by tumor is limited. Diffusion tensor imaging (DTI) is a promising method for visualizing white matter tract tumor involvement supratentorially. We investigated the ability of DTI to visualize and quantify white matter tract involvement in pontine tumors. METHODS AND MATERIALS: DTI data (echo-planar, 1.5T) were retrospectively analyzed in 7 patients with pontine tumors (6 diffuse, 1 focal), 4 patient controls, and 5 normal volunteers. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from the diffusion tensor in 6 regions of interest: bilateral corticospinal tracts, transverse pontine fibers, and medial lemnisci. Relationships between FA and ADC values and results of the neurologic examinations were evaluated. RESULTS: The corticospinal tracts and transverse pontine fibers were affected more often than the medial lemnisci. The DTI parameters (FA and ADC) were significantly altered in all tracts of patients with pontine tumors (P < .05), compared with those values in the control groups. A marginally significant (P = .057) association was seen between the severity of cranial nerve deficit and decreased FA. CONCLUSION: DTI provided superior visualization and quantification of tumor involvement in motor, sensory, and transverse pontine tracts, compared with information provided by conventional MR imaging. Thus, DTI may be a sensitive measure of tract invasion. Further prospective studies are warranted to assess the ability of DTI to delineate tumor focality and improve risk stratification in children with pontine tumors.     

磁共振弥散张量成像对正常大脑白质纤维束构象的初步研究

目的利用磁共振弥散张量成像(DTI)研究正常成人脑内各部位各向异性程度及正常白质纤维束构象特征.方法对25名正常志愿者进行常规MR及DTI序列检查,重建FA图及三维彩色编码张量图.分别在半卵圆中心、基底节区和大脑脚层面测量主要白质束的FA值.结果DTI显示灰质与白质区各向异性存在显著差异,不同部位的白质纤维束各向异性程度亦不相同,且左右两侧基本对称,重建FA图和三维彩色编码张量图可显示白质内大部分主要的白质纤维束.结论DTI可清晰显示脑内白质纤维束的走行及分布,为了解脑功能与白质通路间关系提供了有力研究手段.