脑星形细胞瘤弥散张量成像的初步研究

背景与目的:弥散张量成像(diffusiontensorimaging,DTI)是一种高级的、定量的弥散加权成像形式,它不仅可以计算每一体素内水分子弥散的显著弥散系数(apparentdiffusioncoefficient,ADC),而且可以计算出弥散的各向异性指数。国外对脑肿瘤的研究多采用弥散加权成像,本研究采用DTI方法检测脑内星形细胞瘤患者的肿瘤实质组织、瘤内囊变坏死区、瘤周水肿与正常脑组织中ADC、部分各向异性指数(fractionalanisotropy,FA)及相对各向异性指数(relativeanisotropy,RA)值,及上述指标在星形细胞瘤分级中的价值。方法:对确诊的14例脑星形细胞瘤(1～2级10例,3～4级4例)进行DTI。测定不同组织中ADC、FA及RA值。结果:将14例脑星形细胞瘤作为一组分析时,增强的肿瘤实质组织犤(1.14±0.13)×10-3mm2/s犦、瘤内囊变坏死区犤(2.04±0.50)×10-3mm2/s犦及瘤周水肿组织犤(1.55±0.19)×10-3mm2/s犦的ADC值同正常脑组织犤(0.74±0.08)×10-3mm2/s犦相比均有显著性差异(P<0.05)。肿瘤实性部分的ADC值犤增强区域:(1.14±0.13)×10-3mm2/s,非增强区域:(1.01±0.25)×10-3mm2/s犦同瘤内囊变坏死区、瘤周水肿组织区比较均有显著性差异(P<0.05)。增强的肿瘤实质组织(FA:0.21±0.08,RA:0.23±0.07)、瘤内囊变坏死区(FA:0.14±0.06,RA:0     

弥散张量成像在脑胶质瘤放疗中的应用价值

[目的]利用弥散张量成像探讨脑胶质瘤放疗后的早期变化.[方法]31例诊断明确的脑胶质瘤部分切除术后患者,在放疗前后1周内分别行MRI平扫+增强+DTI检查,分析肿瘤瘤体区及剂量相关区域的FA、ADC值变化.[结果]肿瘤瘤体区放疗后FA及ADC值均升高,放疗前后差异均有统计学意义(P＜0.05).剂量＞60Gy时正常白质FA值放疗后升高,50～60Gy、30～40Gy、20～30Gy区域的正常白质放疗后FA值均下降,差异均无统计学意义(P＞0.05);剂量＞60Gy、50～60Gy、40～50Gy、30～40Gy、20～30Gy区域的ADC值升高,但放疗前后的差异亦无统计学意义(P＜0.05).[结论]放疗前、后肿瘤瘤体区FA、ADC值变化能较早提供肿瘤对放疗反应评估.     

磁共振扩散张量成像定量参数对脑胶质瘤分级的诊断价值

目的:探讨磁共振扩散张量成像（diffusion tensor imaging，DTI）定量参数，是否可以对脑胶质瘤进行分级。方法:选取抚矿总医院2015年2月至2017年11月，经病理证实的脑胶质瘤患者60例，依据WHO肿瘤分级标准，分为高级别组（A组）27例，低级别组（B组）33例，分别给予患者磁共振平扫、增强扫描及DTI，观察图像信号变化规律，并测量DTI定量参数FA值与ADC值。结果:ADC值组间比较，A组病人瘤体和瘤周水肿带的ADC值，与B组病人瘤体和瘤周水肿带的ADC值对比，差异有统计学意义（P<0.05）。A、B组内对比，周围水肿带ADC值大于瘤体ADC值，差异有统计学意义（P<0.05）。FA值组间对比，A、B两组肿瘤主体和瘤体周围水肿带对比，差异无统计学意义（P>0.05）。A、B组内对比，瘤周水肿带的FA值大于肿瘤主体FA值，差异有统计学意义（P<0.05）。结论:DTI定量参数可以对脑胶质瘤进行分级，并获得满意效果。     

脑胶质瘤术后IMRT中弥散张量成像示踪视觉通路纤维束应用研究

目的：探索弥散张量成像（ DTI）示踪视觉通路纤维束融入放疗定位CT制定保护性放疗方案的可行性。方法选取2013—2015年间本院收的31例脑胶质瘤术后拟行放疗患者。所有患者行放疗定位CT、常规平扫或增强MR及DTI检查。将获取的视觉通路纤维束DTI图像与3DT1解剖图像融合,导入TPS。采用IMRT技术分别制定将整体视觉通路纤维束作为OAR进行剂量保护方案和未考虑保护的常规方案。配对t检验两者差异。结果两种放疗计划在保证靶区照射剂量及常规OAR保护情况下,PTV的CI、HI均相近（P＝0．875、0．597）。保护性放疗方案患者患侧视束Dmax、Dmean分别降低至9．01％、9．05％,健侧17．96％、15．52％;患侧视辐射纤维束Dmax、Dmean分别降低至5．37％、5．48％,健侧12．89％、11．21％（所有P＝0．000）。结论利用DTI显示视觉通路纤维束融入放疗定位CT制定保护性放疗方案,可减少整体视觉通路纤维束的辐射剂量,从而最大程度降低放疗后发生视觉功能障碍的风险。     

正电子发射计算机断层成像及核磁共振弥散张量成像对脑胶质瘤复发与放射性脑损伤的鉴别诊断价值

目的探讨正电子发射计算机断层成像(PET/CT)及MRI弥散张量成像对脑胶质瘤复发与放射性脑损伤的鉴别诊断价值。方法选取2015年6月至2018年6月间中国人民武装警察部队海警总队医院收治的145例脑胶质瘤手术后放疗患者,所有患者放疗3～6个月后行PET/CT及MRI弥散张量成像复查。比较患者的临床资料、PET/CT指标及MRI弥散张量成像指标,通过绘制受试者工作特征(ROC)曲线分析各指标鉴别诊断脑胶质瘤复发与放射性脑损伤的价值。结果脑胶质瘤复发患者标准摄取值(SUV)、病灶正常组织比(L/N)、局部脑血容量(r CBV)、局部脑血流量(r CBF)、胆碱/肌酸比值(Cho/Cr)及Cho/N-乙酰天门冬氨酸比值(Cho/NAA)均高于放射性脑损伤,差异均有统计学意义(均P <0. 05); SUV、L/N、r CBV、r CBF、Cho/Cr及Cho/NAA鉴别脑胶质瘤复发与放射性脑损伤的ROC曲线下面积(AUC)分别为0. 874、0. 828、0. 952、0. 928、0. 853及0. 905; r CBV鉴别脑胶质瘤复发与放射性脑损伤的AUC高于L/N和Cho/Cr,差异有统计学意义(P <0. 05); r CBV鉴别脑胶质瘤复发与放射性脑损伤最佳截点为1. 458,敏感度和特异度分别为90. 8%和94. 1%。结论脑胶质瘤复发患者SUV、L/N、r CBV、r CBF、Cho/Cr及Cho/NAA等指标明显升高,高于放射性脑损伤患者,MRI弥散张量成像指标鉴别脑胶质瘤复发与放射性脑损伤优于PET/CT,尤其是r CBV指标,更具临床价值。     

磁共振灌注加权成像和扩散张量成像对脑胶质瘤患者的分级诊断效果

目的探讨磁共振灌注加权成像(PWI)和扩散张量成像(DTI)对脑胶质瘤患者的分级诊断效果。方法回顾性分析2010年1月至2014年6月间接受治疗的80例脑胶质瘤患者,经手术与病理学证实的高级别与低级别患者各40例,对比分析高低级别患者术前磁共振PWI和DTI的检查指标,根据受试者工作特征(ROC)曲线确定诊断阀值、计算敏感度和特异度。结果脑胶质瘤瘤体、瘤周及正常区间的表观扩散系数(ADC)、各向异性分数(FA)、局部脑血流量(r CBF)、局部脑血容量(r CBV)量化值的差异均有统计学意义(P<0.05);高、低级别脑胶质瘤瘤体的相对ADC(r ADC)、相对r CBF(rr CBF)、相对r CBV(rr CBV)量化值差异有统计学意义(P<0.05);脑胶质瘤瘤体ADC、rr CBF、rr CBV的AUC值均>0.9,且敏感度与特异度都很高。结论脑胶质瘤瘤体的ADC、rr CBF及rr CBV的诊断敏感度和特异度都很高;在脑胶质瘤分级诊断的过程中,脑胶质瘤瘤体的ADC、r CBF及r CBV可以作为理想的量化指标。     

弥散张量成像在神经肿瘤外科的临床应用现状

由于神经肿瘤解剖部位的特殊性和复杂性，使神经肿瘤外科不同于其他肿瘤外科。首先，因为有颅骨的限制，取得神经肿瘤的病理标本比较困难，其次，神经外科的最大特点是要尽量切除肿瘤而保留神经功能，所以影像学检查对于神经肿瘤的定位定性诊断十分重要。近来得到迅速发展的弥散张量成像（DTI）技术在这方面具有明显的优势，特别是能够在活体显示脑肿痫和白质纤维的相互关系，对制定治疗计划很有帮助。虽然目前尚存在一定的不足，但已经在神经外科领域显示了巨大的应用价值。本文简单介绍了DTI的基本原理．并回顾目前DTI在神经肿瘤专业方面的应用现状。     

磁共振弥散加权成像在胶质瘤分级中的价值

目的 探讨磁共振弥散加权成像(DWI)及表观弥散系数(ADC)在鉴别胶质瘤瘤体区、瘤周区和正常组织中的应用及鉴别胶质瘤良、恶性的价值.方法 采用Philips 1.5T Achieva超导型磁共振成像仪,对46例胶质瘤患者行常规MRI及DWI,弥散系数b值分别取0和1 000 s/mm2,测量瘤体区、瘤周区及对侧正常组...     

弥散张量成像鉴别良性脑膜瘤亚型及相关研究

目的：探讨弥散张量成像（DTI）鉴别良性脑膜瘤亚型及其在手术中的应用价值。方法：57例经手术病理证实的良性脑膜瘤患者,术前均行头部MRI常规平扫及增强扫描,并加做DTI检查。结果：纤维母细胞型脑膜瘤部分各向异性（FA）值明显高于其它亚型脑膜瘤,差别有显著性意义;表观弥散系数（ADC）值各亚型间有差异,但无显著性意义。弥散张量成像能直观地显示肿瘤与重要神经纤维束的关系,纤维束受累情况与临床症状具有良好相关性;结论：FA值可以作为鉴别纤维母细胞型脑膜瘤与其它良性亚型脑膜瘤的重要参数之一,从中可获得术前关于其软硬度的信息。弥散张量成像对指导脑肿瘤手术及判断预后具有重要临床价值。     

弥散张量成像鉴别良性脑膜瘤亚型及相关研究

目的:探讨弥散张量成像(DTI)鉴别良性脑膜瘤亚型及其在手术中的应用价值.方法:57例经手术病理证实的良性脑膜瘤患者,术前均行头部MRI常规平扫及增强扫描,并加做DTI检查.结果:纤维母细胞型脑膜瘤部分各向异性(FA)值明显高于其它亚型脑膜瘤,差别有显著性意义;表观弥散系数(ADC)值各亚型间有差异,但无显著性意义.弥散张量成像能直观地显示肿瘤与重要神经纤维束的关系,纤维束受累情况与临床症状具有良好相关性.结论:FA值可以作为鉴别纤维母细胞型脑膜瘤与其它良性亚型脑膜瘤的重要参数之一,从中可获得术前关于其软硬度的信息.弥散张量成像对指导脑肿瘤手术及判断预后具有重要临床价值.     

DTI在高级别胶质瘤及转移瘤鉴别诊断中价值初探

 目的　初步研究DTI在高级别胶质瘤和转移瘤鉴别诊断中的作用。方法　对 8例高级别胶质瘤、6例转移瘤患者进行常规MRI及DTI检查 ,测量患侧感兴趣区ADC、FA值 ,部分求出与对侧相应部位兴趣区比值 ,行组间统计学分析。结果　两组间肿瘤实性部分、肿瘤囊性部分ADC值及瘤周水肿ADC比值、FA比值差异无显著性 ,水肿周围正常白质ADC及FA比值两组间差异有显著性。结论　水肿周围正常白质ADC、FA比值的测定有利于高级别胶质瘤与转移瘤的鉴别诊断 ,DTI较常规MRI可更好地观察肿瘤与脑白质的关系。     

前列腺磁共振扩散张量成像研究进展

扩散张量成像（DTI）是一种可以无创反映活体组织内水分子扩散的各向异性程度的磁共振功能成像方法,在前列腺的应用尚处于初步研究阶段。DTI能够提供前列腺的组织微观结构信息,并直观显示前列腺纤维走形,有助于前列腺疾病的诊断及鉴别诊断。文章就DTI在前列腺的研究进展及临床应用近况进行综述。     

Grading Gliomas Capability: Comparison between Visual Assessment and Apparent Diffusion Coefficient (ADC) Value Measurement on Diffusion-Weighted Imaging (DWI)

Background: To compare diagnostic accuracy between DWI visual scale assessment and ADC value measurement of solid portion of the tumor in grading gliomas. Methods: This retrospective study included 38 patients who had pathologically proven gliomas between January 2013 and August 2018 with 18 low grade and 20 high grade tumors. All patients underwent MRI and biopsy. Two readers reviewed DWI visual scale independently. Disagreement was resolved by consensus. One reviewer measured ADC value of entire solid part of the tumor in single axial slice with greatest dimension of tumor which was chosen by consensus. Two data sets of visual scale and ADC value were analyzed and comparison of diagnostic accuracy in glioma grading was done by using area under the curve (AUC) of receiver operating characteristic curve (ROC). Results: Visual scale and ADC value could be used to distinguish between low and high grade gliomas with a statistically significant difference. (P-value 0.002 and <0.001). Almost all high grade gliomas had visual scale 5. The sensitivity, specificity, PPV NPV and accuracy were 50%, 100%, 100% , 64.3%,73.68% respectively. The cutoff level for the ADC value was determined to be 1119.48 x10-6 mm2/s in differentiation between low and high grade gliomas with the sensitivity, specificity, PPV, NPV, accuracy of 90%, 88.89% , 90%, 88.9% and 89.47% respectively. There was no statistically significant difference(P-value = 0.163). Conclusion: Both Visual scale and ADC value were capable of differentiating between low and high grade gliomas. Although visual scale may not replace ADC measurement, larger scale prospective study is needed for validate this initial result.     

1H-MRS在脑胶质瘤诊治中的价值

1H-MRS通过对活体代谢物进行定量分析,可以较早地探测脑胶质瘤代谢异常。1H—MRS不仅为胶质瘤的诊断、鉴别诊断、分级、浸润范围及肿瘤预后判定等提供更加科学、精确及敏感的依据,更为临床的诊治开辟新的途径。     

Optimization of the Parameters for Diffusion Tensor Magnetic Resonance Imaging Data Acquisition for Breast Fiber Tractography at 1.5 T

IntroductionDiffusion tensor MRI has emerged as a promising tool for the analysis of the microscopic properties of tissues. Optimizing image acquisition parameters is essential for producing high-quality DTI. This study aimed to optimize the parameters for DTI data acquisition for breast fiber tractography at 1.5 T.Patients and MethodsA total of 21 healthy volunteers received breast DTI scanning using an ASSET-based EPI technique operated under different parameters including b value, the number of diffusion gradient directions, and spatial resolution. The images were analyzed for signal-to-noise, signal intensity ratio, mean number and length of reconstructive fiber tracts, and fractional anisotropy value.ResultsThe optimal acquisition parameters at 1.5 T for breast DT-MRI fiber tractography were determined as follows: axial 31 direction, b = 600 seconds per mm², matrix 128 × 128 with slice thickness of 3 mm.ConclusionThe optimization of data acquisition parameters could improve the quality of breast DT-MRI images and assist fiber tractography at 1.5 T.     

Two Different Methods of Region-of-Interest Placement for Differentiation of Benign and Malignant Breast Lesions by Apparent Diffusion Coefficient Value

Purpose: We aimed to investigate the influence of different methods of region-of-interest (ROI) placement onapparent diffusion coefficient (ADC) values in breast tumours and their accuracy in differentiating benign versusmalignant tumors in mass and nonmass lesions. Methods and Materials: In this prospective study, 79 patients with98 breast lesions, from 2015 until 2017, were investigated by 1.5-T breast MRI. Histopathology evaluation were donefor all malignant lesions and most of the benign ones. ADC values were measured in normal breast tissue and by twoways of ROI placement in the breast lesions (mass and non-mass): 1- ROI covering the whole lesion, 2- ROI in thehighest part (most restricted area) of the lesion in DWI images. The accuracy of these two approaches were compared.Results: The age range was 17-68 years with mean age 43.3 ± 9.9 years. 49% of the lesions were benign and 51% oftumors were malignant. Our results revealed that the measured ADC values in normal breast tissue were higher thanbreast lesions (P≤0.01). Appropriate cut off determination in non-mass was not valid by both methods, but in mass inthe first way was 1.45×10 -³mm²/s and in the most restricted part was 1.16×10-³ mm²/s. ADC values differed significantlybetween the two ways of ROI placement in mass lesions (P<.001). Most restricted part ADC showed the best diagnosticperformance in mass lesions with area under curve 0.88 versus 0.82. Conclusion: ROI placement has significant impacton the meseaured ADC values of breast lesions and ROIs in most restricted parts were more accurate than whole-lesionROIs. Cut-off values differed significantly based on the methods of measurement.