骨肿瘤的MR灌注和扩散加权成像研究

目的对临床常见的骨肿瘤进行MR灌注成像(PWI)和扩散加权成像(DWI)研究,探讨其在骨肿瘤定性诊断中的价值。方法收集恶性骨肿瘤18例,良性骨肿瘤21例,行MR PWI和MR DWI,应用Functool2软件分析,于灌注像上得到病灶时间-信号曲线(TIC)、首过期(FP)信号递减幅度、TIC最大线性斜率、两次稳态信号差值;于DWI上获得病灶表观扩散系数(ADC)值;采用SPSS13.0统计分析软件,将从良、恶性骨肿瘤两组样本中获得的各种参数用成组设计的两样本均数进行t检验,采用受试者操作特征(ROC)曲线选择良恶性肿瘤鉴别诊断的阈值,计算MR PWI和MR DWI诊断恶性骨肿瘤的敏感度、特异度、和准确度。结果MR PWI显示,17/21的良性骨肿瘤TIC表现为I型(平稳型)及II型(缓降缓升型),恶性骨肿瘤TIC表现为III型和IV型(速降型);良、恶性骨肿瘤之间的FP信号递减幅度、TIC最大线性斜率及两次稳态信号差值在良、恶性骨肿瘤之间的差异均具有显著性统计学意义,其据此诊断恶性骨肿瘤的准确度分别为82.1%、79.5%和87.2%;有4例良性骨肿瘤可根据其MR-PWI作定性判断,结果误诊为恶性肿瘤。MR DWI显示:b=300s/mm2时,良、恶性骨肿瘤的ADC值的差异具有统计学意义;若以ADC1.63×10-3mm2/s为恶性阈值,其诊断恶性骨肿瘤的准确度为79.5%。MR PWI和MR DWI诊断恶性骨肿瘤的准确度分别为89.7%和79.5%。结论MR PWI比MR DWI更有助于鉴别良、恶性骨肿瘤及肿瘤样病变,但恶性骨肿瘤与富血供良性骨肿瘤及肿瘤样病变的灌注参数存在重叠,此时结合MR DWI可以提高诊断准确度。     

颈部淋巴结的MR扩散加权成像

目的评价颈部淋巴结MR扩散加权成像（DWI）的可行性,及其在鉴别正常淋巴结和转移性淋巴结中的价值。资料与方法对34例鼻咽癌患者和14名健康志愿者进行颈部常规MR和DWI,比较两种成像技术对淋巴结的显示能力,并比较正常和转移性淋巴结ADC值差异的统计学意义。扫描采用基于敏感性编码（SENSE）技术的短恢复时间反转恢复（STIR）-平面回波成像序列（EPI）-DWI。结果DWI较常规MR能更敏感地显示淋巴结。正常淋巴结的ADC值为（0．975±0．179）×10^-3mm^2／s,转移性淋巴结的ADC值为（0．744±0．125）×10^-3mm^2／s,两者间的差异有统计学意义（P〈0．01）,转移性淋巴结的ADC值明显低于正常淋巴结的ADC值。结论STIR-EPI-DWI能准确和敏感地显示颈部淋巴结,可作为淋巴结MR成像的一种新手段,并为正常淋巴结和转移性淋巴结的鉴别提供新的方法。     

颞叶癫痫MR扩散加权成像的初步研究

目的 应用MR扩散加权成像技术(DWI)分析颞叶癫痫(TLE)患者的海马扩散运动变化规律,初步探讨表观扩散系数(ADC)对TLE定侧诊断的价值.资料与方法 对临床诊断的42例发作间期TLE患者和32名健康志愿者行常规MRI和DWI检查,定量测量双侧海马的ADC值并统计,同时比较TLE患者与健康志愿者海马ADC值的不对称指数(AIADC).结果 健康志愿者双侧海马ADC值无显著性差异.TLE患者患侧海马、对侧海马及正常人海马ADC值分别为:(0.9357±0.0773) mm2/s、(0.8572±0.0464) mm2/s、(0.8092±0.0303) mm2/s,患侧海马ADC值显著高于对侧海马及正常志愿者(P=0.000).TLE患者及正常人海马的AIADC分别为:(8.5778±7.1720)%、(1.5389±1.4659)%,患者AIADC显著高于正常人(P＝0.000).结论 DWI检查可以反映TLE患者的海马扩散变化,ADC值升高、AIADC增大是TLE病灶定侧诊断的有用指标.     

MR扩散加权及灌注成像对肝癌介入治疗疗效的研究进展

对于临床不能手术切除的肝癌,其经导管肝动脉化疗栓塞(TACE)是主要的治疗方法。TACE术后疗效的早期、准确及有效判断,直接决定病人的后续治疗及预后。以MR扩散加权成像(DWI)、MR灌注加权成像(PWI)为代表的反映微观变化的MR功能成像技术可以先于肿瘤形态学的变化,通过反映细胞密度或肿瘤血管密度,从而帮助早期判断肿瘤治疗的反应。就MRDWI及PWI评价原发肝癌TACE治疗疗效的研究进展进行综述。     

多发性硬化的MR扩散加权成像研究

目的：总结多发性硬化（multiple sclerosis,MS)的扩散加权成像（diffusion-weighted imaging,DWI)表现，定量研究MS病灶区水分子表观扩散系数(apparent diffusion coefficient,ADC）值、扩散各向异性指数（anisotropy index,AI)的变化规律。方法：18例218个病灶分为5组：A组为MS急性期活动性病灶9例72个病灶，B组为A组中4例治疗后随访的病例，共31个病灶，C组为缓解－复发型的缓解期静止病灶9例（115个病灶），D组取病灶对侧或邻近的正常表现白质区域(normal appearance white matter,NAWM)，共218个，E组为正常对照组18例。总结病灶在DWI与常规MRI上的表现。测量病灶及临近正常表现白质区以及正常对照组相应区的ADC、AI。结果：在DWI上，进展型MS表现为高信号（T2WI表现为水肿样高信号）。缓解－复发型的急性发作期MS表现为环形或圆形高信号病灶。缓解－复发型的缓解期病灶与白质相比表现为稍高信号。各种分型与分期的MS病灶的ADC升高，AI下降，与NAWM及正常对照组间存在明显差异（F＝26．89，P＜0．01）。AI在病程后期表现为明显下降。MS病灶在T2WI上表现为高信号。强化MS病灶的ADC值 比非强化病灶的ADC值低（t＝4．19，P＜0．01），而2组的AI值之间无显著性差异（t＝0．99，P＞0．05）。结论：DWI与常规MR相比可以提供定量的诊断信息。能够反映MS不同临床分期的病理变化。扩散定量研究在MS的诊断、鉴别诊断以及疾病预后疗效中有重要的价值。     

MR扩散加权成像在体部的应用

MR扩散加权成像在体部的应用逐渐增多，介绍体部多种组织器官的扩散加权成像技术、表现及其应用价值，并分析体部扩散加权成像存在的问题及原因。     

颈髓MR扩散加权成像优化b值初步研究

目的：探讨1.5T磁共振颈髓扩散加权成像（DWI）b值的选择及获取正常脊髓表观扩散系数（ADC值）。方法：50例健康志愿者进行颈髄DWI检查,采用单次激发平面回波（SSH-EPI-DWI）序列,扩散梯度因子b值分别取300、500和1000 s/mm^2,分3组进行扫描,测量正常人颈髓ADC值并分析各组DWI图像及ADC图像质量,对比不同b值对成像效果的影响。结果：50例受检者均获得较满意的DWI和ADC图像并测得正常人颈髓ADC值。随着b值由300 s/mm^2升高到1000 s/mm^2,图像信号强度逐渐降低。以b值为500 s/mm^2时成像效果较好,信噪比和对比度较高,伪影较少。在500s/mm^2时测得的50例正常颈髓的平均ADC值为（95.70±11.01）×10-5mm^2/s。结论：利用SSH-EPI-DWI序列,正常人颈髓在b值为500 s/mm^2时可获得颈髓较满意的DWI和ADC图像。     

MR扩散加权成像在宫颈癌诊断和分期中的应用价值

目的 探讨磁共振扩散加权成像（DWI）在宫颈癌诊断的敏感性、分期的准确性及盆腔淋巴结转移的检出率和定性准确率中的应用价值.方法 回顾性分析经术后病理证实的98例宫颈癌患者的影像资料,比较DWI联合常规MRI序列与单纯常规MRI序列在宫颈癌诊断、分期及盆腔淋巴结转移方面的差异.结果 DWI联合常规MRI序列对Ⅰb期的漏诊率（1/20）低于单纯常规MRI序列漏诊率（5/20）.DWI联合常规MRI序列对Ⅱb期分期准确率（21/23）高于单纯常规MRI序列准确率（14/23）;其余各期分期,两者无明显差异.DWI联合常规MRI序列对盆腔淋巴结转移的检出率（135/148）和定性准确率（76/82）均高于单纯常规MRI序列的检出率（101/148）和定性准确率（56/82）.结论 相对于常规MRI序列,DWI联合常规MRI序列对宫颈癌的诊断更敏感,Ⅱb期分期更准确,盆腔淋巴结检出率和定性准确率更可靠.     

预测脑卒中的进展:MR磁敏感加权成像与MR灌注成像的比较研究

摘要目的与MR灌注加权成像(PWI)比较,探讨磁敏感加权成像(SWI)在预测脑卒中进展方面的作用。方法对一组(15例)发病24h内的非腔隙性缺血性脑卒中病人的回顾性分析中,我们使用Alberta卒中项目早期CT评分标准(Alberta Stroke Program Early CT Score,ASPECTS)比较了发病初期和发病至少5d后扩散加权成像(DWI)、SWI、PWI上病变的变化。     

MR imaging of edema accompanying benign and malignant bone tumors

To evaluate the incidence, quantity, and presentation of intra- and extraosseous edema accompanying benign and malignant primary bone lesions, the magnetic resonance (MR) studies of 63 consecutive patients with histologically proven primary bone tumors were reviewed. MR scans were assessed for the presence and quantity of marrow and soft tissue edema and correlated with peroperative findings, resected specimens and follow-up data. The signal intensity and enhancement of tumor and edema prior to and after intravenous administration (if any) of gadolinium-labled diethylene triamine pentaacetate (Gd-DTPA) was analyzed. Marrow edema was encountered adjacent to 8 of 39 malignant tumors and 14 of 24 benign lesions. Soft tissue edema was found accompanying 28 of 39 malignancies and 10 of 24 benign disorders. On unenhanced T1-weighted MR images tumor and edema were difficult to differentiate. Tumor inhomogeneity made this differentiation easier on T2-weighted sequences. In 36 patients the contrast medium Gd-DTPA was used. Edema was present in 27 of these patients and the respective enhancement of tumor and edema could be compared. Edema always enhanced homogeneously, and in most cases it enhanced to a similar degree as or more than tumor. Marrow and, more specifically, soft tissue edema is a frequent finding adjacent to primary bone tumors. The mere presence and quantity of marrow and soft tissue edema are unreliable indicators of the biologic potential of a lesion. Unenhanced MR scans cannot always differentiate between tumor and edema, but the administration of Gd-DTPA is of assistance in differentiating tumor from edema. Awareness of marrow and/or soft tissue edema adjacent to bone lesions is of importance because edema can be a pitfall in the diagnostic work-up and staging prior to biopsy or surgery.     

MR扩散加权成像鉴别良恶性骨肿瘤及肿瘤样病变的价值

目的 探讨磁共振扩散加权成像 (DWI)鉴别良、恶性骨肿瘤及肿瘤样病变的价值.方法 选择临床资料完整骨肿瘤及肿瘤样病变患者61例,DWI选用5个不同的弥散敏感系数(b值),分别为0、400、800、1 000、1 500 s/mm2,并得到相应的表观弥散系数(ADC)图,选择感兴趣区计算ADC值,同时选取邻近正常肌肉、骨髓的ADC值作为参照.统计学分析结果以P＜0.05表示差异有统计学意义.结果 (1)良恶性骨肿瘤之间的DWI信号差异无显著性.(2)取b值分别为400、800、1 000 s/mm2和1 500 s/mm2时肿瘤病变实质区ADC值,良性骨肿瘤及肿瘤样病变实质区均高于恶性骨肿瘤实质区,而恶性骨肿瘤实质区又远远大于正常骨髓的ADC值;且良恶性骨肿瘤及肿瘤样病变实质区与正常相邻骨髓的ADC值与b值呈负相关,即随着b值的增高,ADC值降低.结论 磁共振扩散加权成像ADC值有助于鉴别骨肿瘤良恶性病变.     

Perfusion and diffusion MR imaging in enhancing malignant cerebral tumors

OBJECTIVE: Common contrast-enhancing malignant tumors of the brain are glioblastoma multiforme (GBMs), anaplastic astrocytomas (AAs), metastases, and lymphomas, all of which have sometimes similar conventional MRI findings. Our aim was to evaluate the role of perfusion MR imaging (PWI) and diffusion-weighted imaging (DWI) in the differentiation of these contrast-enhancing malignant cerebral tumors. MATERIALS AND METHODS: Forty-eight patients with contrast-enhancing and histologically proven brain tumors, 14 AAs, 17 GBMs, nine metastases, and eight lymphomas, were included in the study. All patients have undergone routine MR examination where DWI and PWI were performed in the same session. DWI was performed with b values of 0, 500, and 1000 mm(2)/s. Minimum ADC values (ADC(min)) of each tumor was later calculated from ADC map images. PWI was applied using dynamic susceptibility contrast technique and maximum relative cerebral blood volume (rCBV(max)) was calculated from each tumor, given in ratio with contralateral normal white matter. Comparisons of ADC(min) and rCBV(max) values with the histological types of the enhancing tumors were made with a one-way analysis of variance and Bonferroni test. A P value less than 0.05 indicated a statistically significant difference. RESULTS: The ADC(min) values (mean+/-S.D.) in GBMs, AAs, lymphomas, and metastases were 0.79+/-0.21 (x10(-3)mm(2)/s), 0.75+/-0.21 (x10(-3)mm(2)/s), 0.51+/-0.09 (x10(-3)mm(2)/s), and 0.68+/-0.11 (x10(-3)mm(2)/s), respectively. The difference in ADC(min) values were statistically significant between lymphomas and GBMs (P<0.05). It was also statistically significant between lymphomas and AAs (P<0.03). However, there were no differences between lymphomas and metastasis, and between GBMs, AAs, and metastasis. The rCBV(max) ratio (mean+/-S.D.) in GBMs were 6.33+/-2.03, whereas it was 3.66+/-1.79 in AAs, 2.33+/-0.68 in lymphomas, and 4.45+/-1.87 in metastases. These values were statistically different between GBMs and AAs (P<0.001), GBMs and lymphoma (P<0.0001). Although there seemed to be difference between GBMs and metastases, it was not statistically significant (P<0.083). CONCLUSION: Combination of DWI and PWI, with ADC(min) and rCBV(max) calculations, may aid routine MR imaging in the differentiation of common cerebral contrast-enhancing malignant tumors.     

MR diffusion imaging in mediastinal masses the differentiation between benign and malignant lesions

Background

Diffusion-weighted imaging is a fundamental tool integrated in MR protocols useful in differentiating benign from malignant mediastinal masses, assessing mediastinal lymphadenopathy and investigating central bronchogenic carcinoma. This method is an excellent alternative to CT or PET/CT in the investigation of mediastinal masses. Current applications of diffusion MRI in malignancies include monitoring the treatment response and detecting recurrent cancer.

Dynamic susceptibility contrast perfusion MR imaging in distinguishing malignant from benign head and neck tumors: A pilot study

Purpose

To preliminarily investigate the utility of dynamic susceptibility contrast perfusion MR imaging in distinguishing malignant from benign head and neck tumors.

Material and methods

Seventy eight patients with head and neck masses underwent single shot dynamic susceptibility contrast T2*-weighted perfusion weighted MR imaging after bolus infusion of gadolinium-DTPA was administrated. The signal intensity time curve of the lesion was created. Dynamic susceptibility contrast percentage (DSC%) was calculated and correlated with pathological findings.

Results

The mean DSC% of malignant tumor (n = 40) was 39.3 ± 9.6% and of benign lesions (n = 38) was 24.3 ± 10.3%. There was a statistically significant difference of the DSC% between benign and malignant tumors (P = 0.001) and within benign tumors (P = 0.001). When DSC% of 30.7% was used as a threshold for differentiating malignant from benign tumors, the best results were obtained: accuracy of 84.6%, sensitivity of 80% and specificity of 89.2%.

Conclusion

Dynamic susceptibility contrast perfusion weighted MR imaging is a non-invasive imaging technique that can play a role in differentiation between malignant and benign head and neck tumors.     

磁共振扩散加权成像在眼眶良恶性肿瘤鉴别中的应用

目的 探讨磁共振扩散加权成像(DWI)及表观扩散系数(ADC)在眼眶良恶性肿瘤鉴别诊断中的价值.方法 回顾性分析40例(良性组∶恶性组=25∶15)眼眶肿瘤病例的DWI及ADC图像,分析其DWI及ADC图像信号特点.逐层勾画肿瘤边界以获得整体感兴趣区(ROD,得到肿瘤平均ADC值(ADCM).眼眶良恶性肿瘤的信号特点比较采用Fisher精确检验,2组间ADCM值比较采用独立样本t检验.炎性假瘤及淋巴瘤的ADCM值比较采用Mann-Whitney U检验.采用受试者工作特征曲线(ROC)法分析AIDCM值对眼眶良恶性肿瘤的鉴别诊断价值.结果 眼眶良恶性肿瘤组间DWI图像信号特点无明显统计学差异(P＞0.05),2组ADC图像信号特点有明显统计学差异(P＜0.05).良性肿瘤的ADCM明显高于恶性肿瘤(P＜0.05),其中炎性假瘤的ADCM明显高于淋巴瘤(P＜0.05).以ADC值≥1.289×10-3 mm2/s判断眼眶肿瘤良恶性,可获得最优的诊断价值[曲线下面积(AUC)0.968;敏感度0.960;特异度0.933].结论 磁共振DWI及ADC值在眼眶肿瘤良恶性鉴别中具有重要价值.     

CT灌注成像对单发骨转移瘤与原发恶性骨肿瘤的鉴别

目的 探讨CT灌注成像在单发骨转移瘤与原发恶性骨肿瘤鉴别诊断中价值.方法 回顾性分析经手术病理证实的14例单发骨转移瘤和15例原发恶性骨肿瘤的CT灌注检查.结果 单发骨转移瘤和原发恶性骨肿瘤在灌注参数方面无明显不同,但在是否伴有高灌注的软组织肿块或低灌注的中央坏死区方面有明显不同:单发骨转移瘤是2例(14.3%),原发恶性骨肿瘤是13例(86.7%).结论 CT灌注成像有助于鉴别单发骨转移瘤与原发恶性骨肿瘤,可以详细全面提供医生制定手术计划所需要的骨肿瘤的性质和血供情况的信息.     

MRI扩散加权成像对乳腺良恶性病变的诊断

目的:探讨磁共振扩散加权成像(DWI)对乳腺良恶性疾病的诊断价值。方法:回顾性分析40例经病理确诊的乳腺疾病,其中良性病变22个,恶性病变18个;均行DWI检查,测定病灶区表观扩散系数(ADC值),与正常组织进行比较,计算相对表观扩散系数(rADC值),应用SPSS 16.0软件比较其平均值,并以病理结果为金标准,作ROC曲线,求其最佳诊断阈值。结果:良性病变及恶性病变的ADC值分别为(1.55±0.35)×10-3和1.00±0.18)×10-3 mm2/s,其rADC值分别为(0.82±0.19)和(0.52±0.08)。良恶性病变组间均有统计学差异,以ADC值及rADC值为诊断标准作受试者工作特征曲线(ROC曲线),其中ADC值的曲线下面积(AUC)为(0.927±0.04),rADC值的AUC为(0.965±0.03),诊断阈值分别为1.17×10-3 mm2/s、0.66,相应敏感度及特异度分别为(90.9%、88.9%)和(95.5%、94.4%),rADC值的AUC、敏感度及特异度均高于ADC值。结论:DWI对乳腺良恶性病变的的诊断具有重要作用,其中rADC值有更好诊断效能。