扩散加权成像在鼻咽癌诊治中的研究现状

鼻咽癌常见于我国华南地区,属头颈部恶性肿瘤,放射治疗为其主要的治疗方法。该病若不及时治疗或治疗不彻底易导致局部复发和远处转移。MR扩散加权成像通过测量ADC值对病变进行定量分析,从而准确诊断鼻咽癌微小病变,评价放疗早期疗效及观察预后。就扩散加权成像在鼻咽癌诊断及治疗中的应用予以综述。     

MRI扩散加权成像在鼻咽癌调强放疗疗效评价中的应用价值

目的 探讨磁共振扩散加权成像(diffusion weighted imaging,DWI)在鼻咽癌调强放射治疗中的临床应用价值.方法 回顾性分析经病理检查证实的60例初诊鼻咽癌患者,均行调强放射治疗,放射治疗前1周内和放射治疗50Gy时均行MRI及DWI检查,比较放疗前后MRI及DWI-MRI情况.结果 56例放疗后肿瘤病灶缩小,3例变化不明显,1例增大,与放疗前比较差异具有统计学意义(P＜0.05).放疗后弥散加权成像信号减低,表观弥散系数(apparent diffusion coefficient,ADC)值增大,与放疗前比较差异具有统计学意义(P＜0.05).52例颈部转移性淋巴结缩小.结论 MRI扩散加权成像可快速,灵敏显示鼻咽癌放疗前后的变化,对IMRT的疗效评价具有很好的临床应用价值.     

鼻咽癌放疗后早期放射性脑损伤的磁共振扩散加权成像研究

目的：探讨磁共振扩散加权成像（DWI）在观察鼻咽癌患者放疗后早期放射性脑损伤方面的价值。方法选取健康志愿者20名,男性10名,女性10名。年龄24-65岁,平均年龄为（43±4）岁。20例鼻咽癌患者,男性11例,女性9例。年龄27-78岁,平均年龄为（50±5）岁。所有健康志愿者均行磁共振成像（MRI）常规平扫及DWI成像,DWI成像时b值分别采用0和1000 s/mm2。结果健康志愿者双侧颞叶的表观弥散系数（ADC）值与鼻咽癌患者放疗前的双侧颞叶的ADC值比较差异无统计学意义。鼻咽癌患者放疗前的双侧颞叶的ADC值与首次放疗后3 d及放疗后3个月双侧颞叶白质的ADC值之间差异有统计学意义,放疗后6个月、12个月及18个月时的双侧颞叶的ADC值与放疗前比较差异无统计学意义。结论磁共振DWI能够反映鼻咽癌放疗后放射性脑损伤的病理变化,是一种能够发现早期放射性脑损伤的影像学诊断方法。     

放射敏感性不同鼻咽癌细胞株的蛋白质组学比较研究

鼻咽癌（NPC）是我国南方常见的恶性肿瘤，放射治疗是鼻咽癌治疗最有效的手段之一。预测肿瘤的放射敏感性将有助于制定合理的放疗方案。目前采用的常规放疗方案没有考虑到不同个体存在放射敏感性的差异，影响了肿瘤的放疗控制率。所以，寻找能准确地预测肿瘤细胞的放射敏感性的蛋白质，对不同患者采用更合理的个体化放疗方案极为重要。蛋白质组学方法使高通量地研究生物个体功能成为可能。在本研究中，将应用蛋白质组学技术初步研究放射敏感性不同鼻咽癌细胞株中差异表达蛋白。     

鼻咽癌放射治疗后“正常脑白质”的DTI及DSC-PWI研究

目的探讨鼻咽癌放疗后急性期与早期迟发性反应期双侧颞叶脑白质磁共振扩散张量成像(DTI)及动态敏感对比增强灌注加权成像(DSC-PWI)的变化特点。方法鼻咽癌放疗前及放疗后复查患者各16例,放疗前患者作为对照组,放疗后患者处于放疗后0～6个月内,即放疗后急性期与早期迟发性反应期,作为试验组。两组间性别、年龄、受教育程度、吸烟及饮酒等因素无统计学差异。所有受试者均行扩散张量成像(DTI)及动态敏感对比增加灌注加权成像(DSC-PWI)检查,原始图像进行后处理后,测量各组双侧颞叶DTI的各向异性分数(FA)、平行本征值(λ║)及垂直本征值(λ⊥),以及各组双侧颞叶PWI的相对血流量(rCBF),所得数据进行两独立样本t检验。结果放疗后FA值与对照组相比显著降低,放疗后λ║与放疗前相比显著降低,放疗后λ⊥与放疗前相比显著升高;放疗后rCBF值比对照组明显降低,且差异有统计学意义。结论 DTI和DSC-PWI可以显示放疗后神经组织及血管的显微损伤,血管损伤及其所致的血流量减低可能参与了放射治疗诱发的早期脑组织损伤。     

磁共振扩散加权成像在评估鼻咽癌放射治疗中的应用

目的 探讨磁共振扩散加权成像(DW-MRI)在鼻咽癌放射治疗中的应用价值.方法 经穿刺活检病理确诊鼻咽癌病例15例,在放射治疗前及放射治疗剂量达10、20 Gy及40 Gy时行磁共振检查(包括常规MRI及DW-MRI),观察肿瘤原发灶及颈部转移淋巴结大小、DWI信号及ADC值的变化.结果 放疗前DWI序列显示肿瘤原发灶最大层面面积要明显小于增强T1WI脂肪抑制序列(P<0.05);肿瘤原发灶及转移淋巴结在放疗后T2WI信号不均匀增高,其ADC值在放疗后逐渐升高,放疗前及放疗剂量达40 Gy时ADC值分别为(0.690±0.072)×10-3 mm2/s和(0.813±0.091)×10-3 mm2/s及(1.167±0.057)×10-3 mm2/s和(1.802±0.173)×10-3 mm2/s,且放疗前后各组间相互差异均有统计学意义(P<0.05);放疗前转移淋巴结最大层面面积为(2.58±0.64) cm2,放疗剂量达10 Gy时为(1.07±0.25) cm2,缩小率为58.5%,而肿瘤原发灶缩小率为2%.结论 与常规磁共振比较,扩散加权成像能更早、更特异、更敏感地反映鼻咽癌放疗后的生物学变化,对其疗效的监测具有重要价值.     

MRI在子宫肉瘤和子宫肌瘤鉴别诊断中的应用进展

子宫肉瘤与子宫肌瘤的治疗方案和预后管理完全不同,对两者的鉴别诊断至关重要。MRI是诊断子宫肿瘤的重要影像方法,尤其是扩散加权成像（DWI）、扩散张量成像（DTI）、扩散峰度成像（DKI）、灌注加权成像（PWI）、MR波谱成像（MRS）、增强梯度回波T₂*加权血管成像（ESWAN）等功能MRI及影像组学,在子宫良恶性肿瘤鉴别、病理分型分级和分子变化等方面可以进行量化分析,从而提供更多有价值的信息。就MRI在鉴别子宫肉瘤和子宫肌瘤中的应用进展作一综述。     

磁共振DWI、PWI联合应用对鼻咽癌放疗效果的评价

目的探讨磁共振弥散加权成像(DWI)、灌注成像(PWI)联合应用在评价鼻咽癌放疗后效果中的应用价值。方法 48例鼻咽癌患者,入院前均未有相关治疗史,入院后所有患者先行一次常规MR、MR-DWI及MR-PWI检查,然后再行4周根治性放射治疗,待放疗周期完成后再行一次常规MR、MR-DWI及MR-PWI检查,最后对比分析放疗前后鼻咽部肿块在不同MR成像方法中的变化。结果放疗前鼻咽癌肿块在DWI图像上弥散受限(ADC值较高),PWI图像上血流灌注较丰富(血容量BV较高);图像上显示的弥散受限区域及高灌注区域最大层面面积,同放疗前增强T1WI脂肪抑制序列相比均要小(P0.05),而弥散受限区域稍大于高灌注区域(P0.05,两者无统计学差异);行根治性放射治疗后,敏感组鼻咽部肿块弥散受限区域、高灌注区域面积均明显下降,与增强T1WI脂肪抑制序列相比,下降更明显(P0.05);肿瘤放疗后复发不同于放疗后坏死或纤维化,复发表现为弥散受限、血容量BV升高,而坏死或纤维化表现为弥散不受限、血容量BV下降(P0.05)。结论在反应鼻咽癌放疗前后形态及生物学变化方面,常规MRI检查结合MRDWI、MR-PWI成像更准确;在评价鼻咽癌放疗的敏感性,鉴别肿瘤放疗后复发、坏死或纤维化中,弥散ADC值、灌注血容量BV参数均具有较重要的参考价值。     

磁共振扩散、灌注、波谱成像技术在肿瘤治疗疗效监测中的应用

肿瘤治疗疗效监测对判断肿瘤预后及治疗方案的调整至关重要。对肿瘤治疗疗效进行监测以及区分有无治疗反应的肿瘤类型,都需要早期的、直观的、动态的、精确的方法。随着多种新技术的出现,人们对肿瘤的生物学行为和治疗疗效反应有了更进一步的理解。就磁共振扩散加权成像（DW-MRI）、磁共振动态增强成像（DCE-MRI）和磁共振波谱成像（MRS）在预测和检测肿瘤治疗疗效中的应用进行综述。     

PIK3CA在不同鼻咽癌细胞株中的表达及其与放射敏感性的关系

放射治疗是鼻咽癌的主要治疗手段,而相对放射抵抗的亚细胞系残存并增殖,成为复发的根源.临床实践表明,即使是同一病理类型的鼻咽癌患者对放射线的敏感性也不同,对于不同的鼻咽癌患者的治疗需要放疗的个体化.因此,发现预测鼻咽癌放射敏感性相关分子标志物,对指导鼻咽癌个体化治疗和改善其预后具有重要的意义.     

3.0T MR DWI预测鼻咽癌放化疗敏感性的研究

目的探讨3.0 T MR扩散加权成像(DWI)在评估鼻咽癌(NPC)放化疗(CRT)疗效中的价值,预测NPC对CRT的敏感性。方法收集32例经病理证实的NPC病人,行常规MRI及DWI检查,测量CRT前与CRT5周时NPC及转移性淋巴结最大者的体积和ADC值。以CRT后1个月病理活检和MRI检查作为疗效评价标准将NPC分为低敏感与高敏感组,比较CRT 5周时NPC低敏感组与高敏感组ADC值、治疗前后ADC值变化率(ΔADC)及体积消退率(ΔV)的差异;分析影响NPC CRT敏感性的相关因素。结果CRT 5周时NPC ADC值、ΔADC及ΔV在高、低敏感组之间差异均有统计学意义(P0.05),ΔADC为鉴别低敏感与高敏感组最佳指标,其截断值为98.125%,敏感度为95.5%,特异度为90%。非线性Logistic回归分析影响NPC CRT敏感性的相关因素(性别、年龄、治疗方式、T分期及ΔADC),结果显示ΔADC是影响NPC CRT敏感程度的独立预后因素,其相对风险度为1.155。结论 DWI对于评价NPC CRT疗效有重要作用。CRT 5周时NPC ADC值、ΔADC及ΔV都能有效预测NPC CRT敏感性,ΔADC是预测NPC CRT敏感性的最佳指标及独立预后因素。     

磁共振弥散成像在鼻咽癌颈部淋巴结转移调强放射治疗中的应用

目的 探讨磁共振弥散成像(DWI)及表观弥散系数(ADC)在鼻咽癌颈部淋巴结转移调强放射治疗(intensity modulated radiation therapy,IMRT)前的诊断及其对放化疗反应的监测能力.方法 对18例病理确诊的鼻咽癌患者在治疗前、治疗中每周及治疗后1个月行DWI检查.所有患者均接受头颈部IMRT及铂类同步化疗.在DWI上共分析了52枚颈部异常淋巴结,将其分为最短径≥10 mm(32枚)及<10 mm(20枚)两组,测量比较治疗前两组的ADC值是否存在差异,观察所有淋巴结治疗过程中ADC值的动态变化,同时观察比较治疗后残存的颈部淋巴结与正常舌肌的ADC值.结果 最短径≥10 mm淋巴结的平均ADC值为(0.71±0.12)×10-3mm/s,与最短径<10 mm者的平均ADC值[(0.73±0.16)×10-3mm/s]差异无统计学意义(t=1.11,P=0.27).治疗前52枚淋巴结的平均ADC值明显低于正常舌肌(t=19.35,P＜0.01).治疗过程中ADC值逐渐上升,以第1、2周改变最明显,以后趋于平稳.治疗后残留淋巴结的ADC值明显增大,与治疗前比较差异有统计学意义(t=12.72,P＜0.01),与正常舌肌比较差异无统计学意义(t=0.34,P=0.73).结论 在鼻咽癌IMRT中,DWI对诊断颈部转移性淋巴结以及监测后者对放化疗的反应具有重要参考价值,从而帮助临床医生合理制定并及时更改放疗计划.

Abstract：

Objective To investigate the value of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficients (ADC) in detecting metastatic lymph nodes from nasopharyngeal carcinoma (NPC),and predicting the response of these nodes to concurrent chemoradiation (CRT).Methods Eighteen patients with pathologically proven NPC received conventional magnetic resonance imaging (MRI) and DWI before treatment,weekly during treatment,and one month after treatment.DWI was performed using a single-shot echo-planar (SSEPI) MR imaging sequence with b values of 0 and 1500 s/mm2.ADC maps were reconstructed for all patients and ADC values were calculated for each lymph node and tongue muscle.Totally fifty-two morphologically abnormal lymph nodes were analyzed.The ADC values of the metastatic lymph nodes before treatment were compared between those with the short axis≥10 mm (n=32) and those with the short axis<10 mm (n=20),and the dynamic changes in ADC values of the lymph nodes before,during,and after therapy were observed and recorded.Results The average ADC of the 32 lymph nodes with the short axis ≥ 10 mm was (0.71±0.12) x 10-3mm/s,not significantly different from that of the 20 lymph nodes with the short axis < 10 mm [(0.73±0.16) x 10-3mm/s,t = 1.11 ,P =0.27].The average ADC values of these lymph nodes before treatment was significantly lower than that of the tongue muscle (t = 19.35,P < 0.0001).During CRT,the ADC values of the lymph nodes increased gradually,with the most evident change in the first two weeks before reaching a relatively flat plateau thereafter.The ADC value of the residual lymph nodes after CRT was significantly higher than that before treatment (t = 12.72,P < 0.0001),however,not statistically significant different from that of the normal tongue muscle (t = 0.34,P = 0.73).Conclusions DWI plays an important role in diagnosing the metastatic lymph nodes from NPC and is feasible for observation of the early response of the lymph nodes to IMRT,thus helping the clinicians make appropriate treatment planning and replanning in the course of radiotherapy.     

Diffusion-weighted and diffusion-tensor imaging of normal and diseased uterus

Owing to technical advances and improvement of the software, diffusion weighted imaging and diffusion tensor imaging (DWI and DTI) greatly improved the diagnostic value of magnetic resonance imaging (MRI) of the pelvic region. These imaging sequences can exhibit important tissue contrast on the basis of random diffusion (Brownian motion) of water molecules in tissues. Quantitative measurements can be done with DWI and DTI by apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values respectively. ADC and FA values may be changed by various physiological and pathological conditions providing additional information to conventional MRI. The quantitative DWI assists significantly in the differentiation of benign and malignant lesions. It can demonstrate the microstructural architecture and celluler density of the normal and diseased uterine zones. On the other hand, DWI and DTI are useful for monitoring the treatment outcome of the uterine lesions. In this review, we discussed advantages of DWI and DTI of the normal and diseased uterus.     

Diffusion-weighted imaging of pancreatic cancer

Magnetic resonance imaging (MRI) is a reliable and accurate imaging method for the evaluation of patients with pancreatic ductal adenocarcinoma (PDAC). Diffusion-weighted imaging (DWI) is a relatively recent technological improvement that expanded MRI capabilities, having brought functional aspects into conventional morphologic MRI evaluation. DWI can depict the random diffusion of water molecules within tissues (the so-called Brownian motions). Modifications of water diffusion induced by different factors acting on the extracellular and intracellular spaces, as increased cell density, edema, fibrosis, or altered functionality of cell membranes, can be detected using this MR sequence. The intravoxel incoherent motion (IVIM) model is an advanced DWI technique that consent a separate quantitative evaluation of all the microscopic random motions that contribute to DWI, which are essentially represented by molecular diffusion and blood microcirculation (perfusion). Technological improvements have made possible the routine use of DWI during abdominal MRI study. Several authors have reported that the addition of DWI sequence can be of value for the evaluation of patients with PDAC, especially improving the staging; nevertheless, it is still unclear whether and how DWI could be helpful for identification, characterization, prognostic stratification and follow-up during treatment. The aim of this paper is to review up-to-date literature data regarding the applications of DWI and IVIM to PDACs.     

Diffusion weighted imaging: Technique and applications

Diffusion weighted imaging (DWI) is a method of signal contrast generation based on the differences in Brownian motion. DWI is a method to evaluate the molecular function and micro-architecture of the human body. DWI signal contrast can be quantified by apparent diffusion coefficient maps and it acts as a tool for treatment response evaluation and assessment of disease progression. Ability to detect and quantify the anisotropy of diffusion leads to a new paradigm called diffusion tensor imaging (DTI). DTI is a tool for assessment of the organs with highly organised fibre structure. DWI forms an integral part of modern state-of-art magnetic resonance imaging and is indispensable in neuroimaging and oncology. DWI is a field that has been undergoing rapid technical evolution and its applications are increasing every day. This review article provides insights in to the evolution of DWI as a new imaging paradigm and provides a summary of current role of DWI in various disease processes.     

DWI技术在肝外胆管细胞癌诊断、分期和 疗效评估中的研究进展

肝外胆管细胞癌（EHCC）是第二大原发性肝胆系统肿瘤,其恶性程度高,预后不良。扩散加权成像（DWI）是反映组织水分子扩散运动的常用无创性成像方法。近年来,DWI及体素内不相干运动（IVIM）、扩散张量成像（DTI）及扩散峰度成像（DKI）等衍生技术已广泛应用于EHCC的诊断、病理分期预测和监测以及疗效评估。就DWI及其衍生序列对EHCC应用的研究进展以及局限性和应用前景予以综述。     

创伤性脑损伤弥散加权及弥散张力成像研究

磁共振弥散加权及弥散张力成像是基于水分子运动的成像技术,提供脑生理或病理状态的信息,为创伤性脑损伤,特别是弥漫性轴索损伤的早期诊断、指导临床治疗及预测预后提供一定信息,作为传统影像学的补充,弥散加权成像及弥散张力成像越来越成为TBI检查的可供选择的有价值的方法。     

磁共振扩散加权成像在颅内表皮样囊肿中的诊断价值

目的：探讨磁共振扩散加权成像（DWI）在颅内表皮样囊肿中的诊断价值。方法：收集颅内表皮样囊肿病例16例，均行常规MRI和DWI检查，分析表皮样囊肿在T2WI、T1WI、增强扫描和DWI上的影像表现。结果：16例均呈长T2长T1信号，其中2例伴短T2间隔信号，增强扫描14例无强化，2例呈包膜和间隔强化。16例DWI上均呈明显高信号。结论：磁共振DWI在颅内表皮样囊肿中具有重要的诊断价值，可作为常规MRI的重要补充检查方法。