常规MRI结合DWI在良恶性脑膜瘤鉴别诊断中的应用

目的：探讨常规MRI结合扩散加权成像（DWI）在良、恶性脑膜瘤鉴别诊断中的临床应用。方法：对56例良性（Ⅰ级）、11例非典型性（Ⅱ级）和4例间变性脑膜瘤（Ⅲ级）患者行常规MRI和DWI检查,所有病例均经手术和病理证实。结果：①良、恶性脑膜瘤的最常见部位均位于额部;两者在肿瘤大小、形态和信号特点等方面均无明显差异;但恶性脑膜瘤在肿瘤囊变坏死、边缘不规整、周围水肿、肿瘤强化方式和脑膜尾征等征象发生率上明显高于良性脑膜瘤,两者之间差异有明显统计学意义;肿瘤侵犯脑实质或（和）破坏周围颅骨是诊断恶性脑膜瘤较为特异性征象;②良、恶性脑膜瘤的扩散系数（ADC）值分别为（8.73±1.68）×10^-9mm^2/s、（7.26±3.22）×10^-9mm^2/s,两者之间差异存在显著性意义。结论：常规MRI对于良恶性脑膜瘤的鉴别诊断有一些特征性征象,结合ADC值的变化,能明显提高对于良恶性脑膜瘤的鉴别诊断。     

Preoperative subtyping of meningiomas by perfusion MR imaging

Introduction  This paper aims to evaluate the value of perfusion magnetic resonance (MR) imaging in the preoperative subtyping of meningiomas by analyzing the relative cerebral blood volume (rCBV) of three benign subtypes and anaplastic meningiomas separately. Materials and methods  Thirty-seven meningiomas with peritumoral edema (15 meningothelial, ten fibrous, four angiomatous, and eight anaplastic) underwent perfusion MR imaging by using a gradient echo echo-planar sequence. The maximal rCBV (compared with contralateral normal white matter) in both tumoral parenchyma and peritumoral edema of each tumor was measured. The mean rCBVs of each two histological subtypes were compared using one-way analysis of variance and least significant difference tests. A p value less than 0.05 indicated a statistically significant difference. Results  The mean rCBV of meningothelial, fibrous, angiomatous, and anaplastic meningiomas in tumoral parenchyma were 6.93 ± 3.75, 5.61 ± 4.03, 11.86 ± 1.93, and 5.89 ± 3.85, respectively, and in the peritumoral edema 0.87 ± 0.62, 1.38 ± 1.44, 0.87 ± 0.30, and 3.28 ± 1.39, respectively. The mean rCBV in tumoral parenchyma of angiomatous meningiomas and in the peritumoral edema of anaplastic meningiomas were statistically different (p < 0.05) from the other types of meningiomas. Conclusion  Perfusion MR imaging can provide useful functional information on meningiomas and help in the preoperative diagnosis of some subtypes of meningiomas.     

纤维母细胞型脑膜瘤在弥散张量磁共振成像上的表现

目的探讨纤维母细胞型脑膜瘤在弥散张量磁共振成像(DTMRI)上的表现。方法对手术病理证实的2例纤维母细胞型脑膜瘤与20例其他亚型脑膜瘤患者的DTMRI表现进行对照分析。结果 2例纤维母细胞型脑膜瘤中,DTI纤维示踪图像1例表现为"花簇样",1例表现为"线团样"。20例其他亚型脑膜瘤DTI张量纤维示踪图像未见上述征象。结论脑膜瘤DTI纤维示踪图像显示的"花簇样""、线团样"表现,提示纤维母细胞型脑膜瘤的诊断。     

恶性脑膜瘤的CT、MR及病理研究

目的：探讨恶性脑膜瘤CT、MR表现及其病理学特点。方法：分析11例经临床和病理证实的恶性脑膜瘤CT、MR表现及其病理学改变。探讨CT、MRI诊断恶性脑膜瘤的临床价值。结果：11例恶性脑膜瘤中，顶部镰旁4例，额部镰旁3例，颞极1例，大脑凸面3例。边缘光滑者4例，边缘呈不规则分叶状者7例；密度及信号均匀者4例，混杂密度及信号者7例，内部可见囊变、坏死。灶周无水肿2例，轻度水肿2例，中度水肿4例，重度水肿3例；增强后见硬膜尾征4例，形态光整1例，结节状增厚3例；邻近颅骨破坏3例；1例胸腰椎多发转移，骨质破坏。结论：恶性脑膜瘤CT、MRI具有较为特殊的影像学特点。术前正确认识其表现，有助于制订手术方案。     

Utilization of glutamate/creatine ratios for proton spectroscopic diagnosis of meningiomas

Introduction Our purpose was to determine the potential of metabolites other than alanine to diagnose intracranial meningiomas on proton magnetic resonance spectroscopy (MRS). Methods Using a 1.5-T MR system the lesions were initially identified on FLAIR, and T1- and T2-weighted images. Employing standard point-resolved spectroscopy (PRESS) for single voxel proton MRS (TR 1500 ms, TE 30 ms, 128 acquisitions, voxel size 2 × 2 × 2 cm, acquisition time 3.12 min), MR spectra were obtained from 5 patients with meningiomas, from 20 with other intracranial lesions, and from 4 normal controls. Peak heights of nine resonances, including lipid, lactate, alanine, NAA (N-acetylaspartate), β/γ-Glx (glutamate + glutamine), creatine, choline, myo-inositol, and α-Glx/glutathione, were measured in all spectra. The relative quantity of each metabolite was measured as the ratio of its peak height to the peak height of creatine. Results Relative quantities of α-Glx/glutathione, β/γ-Glx, and total Glx/glutathione were significantly elevated in meningiomas compared to the 20 other intracranial lesions and the normal control brains. Alanine was found in four of five meningiomas, but lactate partially masked the alanine in three meningiomas. None of the other lesions or control brains showed an alanine peak. The one meningioma with no alanine and the three others with lactate had elevated Glx. Conclusion While alanine is a relatively unique marker for meningioma, our results support the hypothesis that the combination of glutamate/creatine ratios and alanine on proton MRS is more specific and reliable for the diagnosis of meningiomas than alanine alone.     

对良、恶性椎体压缩性骨折MRI鉴别诊断的再认识

目的：提高对椎体压缩性骨折定性征象的认识。方法：回顾性分析经临床确诊的椎体压缩性骨折56例78个椎体，外伤性骨折11例15个椎体；非外伤性骨折17例25个椎体；恶性压缩性骨折28例38个椎体，MRl分别重点观察了椎体骨髓信号、椎体后缘的形态、MRI增强的强化方式、椎弓根的形态及椎旁软组织的形态。结果：恶性压缩性骨折较特异性的MRI征象有：(1)L1WI像上椎体呈广泛均匀低信号；(2)椎体后缘呈球形凸出；(3)T2WI像上椎弓根膨大且可见高信号；(4)T2WI／I像受累椎体的不均一强化；(5)瘤样椎旁软组织肿块。结论：MRI的特征性改变能准确地鉴别良、恶性椎体压缩性骨折。     

MR扩散加权成像在眼眶良恶性肿块鉴别诊断中的应用

目的 分析眶内良恶性肿块的扩散加权成像(DWI)特征,评价表观扩散系数(ADC)值对其诊断价值.方法 对77例眶内肿块进行常规MRI及DWI,其中良性肿块55例,恶性肿块22例.扩散敏感系数(b)值=0、1000 s/mm2,测量病变对侧颞叶脑白质感兴趣区DWI信号,获得相应的肿块区ADC(ADCM)值、病变对侧颞叶脑白质ADC(ADCw)值,计算二者比值(ADCR).以不同ADCM值及ADCR作为临界点区分眶内良恶性肿块绘制出受试者工作特征曲线(ROC).结果 眶内良性肿块ADCM值及ADCR分别为(1.56±0.75)×10-3mm2/s、1.85±0.91;恶性肿块ADCM值及ADCR分别为(1.09±0.42)×10-3mm2/s、1.28±0.53;良性肿块ADCM值及ADCR显著高于恶性肿块(t值分别为2.803、2.735,P值均＜0.01).以不同ADCM值、ADCR作为临界点判断眶内良恶性肿块绘制ROC,曲线下面积均为0.71±0.07.以ADCM值为1.05×10-3mm2/s作为判断眶内良恶性肿块的决定值,灵敏度、特异度和准确率分别为59.1%(13/22)、78.2%(43/55)和72.7%(56/77);以ADCR为1.24作为决定值,灵敏度、特异度和准确率分别为59.1%(13/22)、76.4%(42/55)和71.4%(55/77).结论 DWI可揭示眼眶肿块的扩散特征,ADC值对于良恶性肿块的鉴别诊断具有辅助诊断价值.     

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.

MR动态增强扫描时间一信号强度曲线在骨骼肌肉系统肿瘤定性诊断中的价值

目的 探讨动态增强MRI时间一信号强度曲线(TIC)上升段最大斜率值和曲线类型在骨骼肌肉系统良、恶性肿瘤鉴别中的作用.方法 采用多时相增强快速采集梯度同波序列,对93例骨骼肌肉系统肿瘤进行MR动态增强扫描,在斜率图上选取ROI,经Functool软件后处理,得到TIC,并将曲线分为Ⅰ、Ⅱ、Ⅲ型,计算曲线上升段最大斜率值.以病理结果为金标准,对TIC类型在良、恶性肿瘤中的分布差异和曲线的上升斜率值进行χ2检验或t检验.结果 49例恶性肿瘤中,37例为I型曲线,12例为Ⅱ型曲线;44例良性肿瘤中,26例为Ⅰ型曲线,7例为Ⅱ型曲线,11例为Ⅲ型曲线,曲线类型在良、恶性肿瘤中的分布差异具有统计学意义(χ2:14.008,P<0.01).良、恶性肿瘤曲线上升斜率值分别为6.80±3.35和6.80±2.71,差异无统计学意义(t=0.008,P＞0.05).与形态学表现相结合,应用TIC类型对骨骼肌肉系统恶件肿瘤定性诊断的敏感度为100%,特异度为50%,阳性预测值为78%,阴性预测值为100%,准确度为82%.结论 TIC类型结合形态学表现,能够提高MRI对骨骼肌肉系统肿瘤良、恶性鉴别的能力.     

Multimodal MRI in the characterization of glial neoplasms: the combined role of single-voxel MR spectroscopy,diffusion imaging and echo-planar perfusion imaging

INTRODUCTION: Diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and MR spectroscopy (MRS) provide useful data for tumor evaluation. To assess the contribution of these multimodal techniques in grading glial neoplasms, we compared the value of DWI, PWI and MRS in the evaluation of histologically proven high- and low-grade gliomas in a population of 105 patients. METHODS: Independently for each modality, the following variables were used to compare the tumors: minimum apparent diffusion coefficient (ADC) and maximum relative cerebral blood volume (rCBV) normalized values between tumor and healthy tissue, maximum Cho/Cr ratio and minimum NAA/Cr ratio in tumor, and scored lactate and lipid values in tumor. The Mann-Whitney and Wilcoxon tests were employed to compare DWI, PWI and MRS between tumor types. Logistic regression analysis was used to determine which parameters best increased the diagnostic accuracy in terms of sensitivity, specificity, and positive and negative predictive values. ROC curves were determined for parameters with high sensitivity and specificity to identify threshold values to separate high- from low-grade lesions. RESULTS: Statistically significant differences were found for rCBV tumor/normal tissue ratio, and NAA/Cr ratio in tumor and Cho/Cr ratio in tumor between low- and high-grade tumors. The best performing single parameter for group classification was the normalized rCBV value; including all parameters, statistical significance was reached by rCBV tumor/normal tissue ratio, NAA/Cr tumor ratio and lactate. From the ROC curves, a high probability for a neoplasm to be a high-grade lesion was associated with a rCBV tumor/normal tissue ratio of >1.16 and NAA/Cr tumor ratio of <0.44. CONCLUSION: Combining PWI and MRS with conventional MR imaging increases the accuracy of the attribution of malignancy to glial neoplasms. The best performing parameter was found to be the perfusion level.     

Magnetic resonance imaging of xanthomatous meningioma

Summary A case of meningioma with extensive xanthomatous metaplasia occurring in the left frontal convexity of a 37-year-old woman is reported. The tumour was demonstrated as a hypodense mass with minimal enhancement on CT. Our findings suggest that magnetic resonance imaging may provide a clue to the diagnosis of meningiomas with extensive xanthomatous metaplasia when CT is less specific.     

Differentiation of benign and malignant ampullary obstructions on MR imaging

Objective

To define diagnostic criteria for differentiating malignant ampullary carcinoma from benign ampullary obstruction on MR imaging.

Materials and methods

Nineteen patients with ampullary carcinoma and 22 patients with benign ampullary obstruction were enrolled. At the first session, two radiologists independently evaluated specific imaging findings, and then reached consensus decisions. At the second session, another two radiologists, who were informed about useful differentiation criteria based on the results from the first session, reviewed images and determined the causes of ampullary obstruction. Sensitivity and specificity were calculated for each interpretation session, and the Cohen κ statistic was used to evaluate interobserver agreement.

Results

Findings of the presence of an ampullary mass (P < 0.001), papillary bulging (P < 0.001), irregular (P = 0.021) and asymmetric (P < 0.001) common bile duct (CBD) narrowing, and proportional biliary dilatation (P < 0.001) were more commonly seen in patients with an ampullary carcinoma. The sensitivity and specificity of the first session were 84.2% and 86.4% after consensus. The sensitivity increased to 100% for both the readers at the second session, while the specificity decreased to 63.6% and 59.1%, respectively.

Conclusions

Identification of an ampullary mass, papillary bulging, irregular and asymmetric narrowing of the CBD, or proportional biliary dilatation may improve the diagnosis of ampullary carcinoma in patients with ampullary obstruction.     

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。     

仿真开颅手术显示大脑浅静脉及其与脑膜瘤关系的应用价值研究

目的 评价仿真开颅手术在显示大脑浅静脉及其与大脑凸面、矢状窦旁及大脑镰旁脑膜瘤关系中的作用.方法 应用仿真开颅手术和三维对比增强MR静脉成像技术(3D CE-MRV)前瞻性地检查49例大脑凸面、矢状窦旁及大脑镰旁脑膜瘤,并进行图像后处理.采用t检验比较两种技术对大脑浅静脉显示数量的差异;评价仿真开颅手术重组图像显示脑膜瘤-大脑浅静脉关系的能力;对影响仿真开颅手术重组效果的脑膜强化与否、肿瘤大小和位置等因素采用Wilcoxon符号秩和检验进行分析.结果 仿真开颅手术和3D CE-MRV显示脑膜瘤周围大脑浅静脉分别为(4.4±1.9)和(5.1±2.7)支,差异有统计学意义(t=3.131,P＜0.05).仿真开颅手术能清楚显示脑膜瘤与大脑浅静脉关系,总平均得分为(2.5±0.7)分.有脑膜强化(12例)和无明显脑膜强化(37例)患者的主观评分分别为(1.5±0.5)、(2.8±0.3)分,无脑膜强化的图像质量明显优于有脑膜强化(Z＝-3.093,P＜0.05);小脑膜瘤组(31例)和大脑膜瘤组(18例)的主观评分分别为(2.7±0.5)、(2.2±0.9)分,小脑膜瘤组明显优于大脑膜瘤组(Z=-2.057,P＜0.05);窦镰组(39例)和凸面组(10例)主观评分分别为(2.6±0.6)、(2.2±0.9)分,两组间差异无统计学意义(Z=-0.604,P＞0.05).结论 仿真开颅手术仅显示大脑浅静脉(SCVs),避免了大脑深静脉和头皮静脉的重叠,对大脑浅静脉评价更加准确;仿真开颅手术能较好地显示脑膜瘤与大脑浅静脉的关系,为脑膜瘤术前选择颅骨开窗位置、术中定位以及保护大脑浅静脉提供帮助.     

表观扩散系数值鉴别良恶性骨肿瘤及肿瘤样病变的价值

目的 探讨MR DWI的ADC值鉴别良、恶性骨肿瘤及肿瘤样病变的价值.方法 对18例良性骨肿瘤及肿瘤样病变和26例恶性骨肿瘤行DWI.采用单激发EPI序列,3个扩散敏感梯度,b值分别为0.500、1000 s/nun2.在ADC图上测量每个病变的最低、最高和整体ADC值.结果 良性骨肿瘤及肿瘤样病变的最低ADC值[(1.28±0.49)×10-3mm2/s]高于恶性骨肿瘤[(0.92±0.35)×10-3mm2/s,t=2.839,P<0.01],整体ADC值[(1.62±0.51)×10-3mm2/s]也高于恶性骨肿瘤[(1.21±0.36)×10-3mm2mm/s,t=3.092,P<0.01],但两者都有很大重叠.良性骨肿瘤及肿瘤样病变的最高ADC值[(2.02±0.55)×10-3mm2/s]与恶性骨肿瘤的最高ADC值[(1.71±0.65)×10-3mm2/s]差异无统计学意义(t:1.669,P＞0.05).去掉以囊腔为主的骨囊肿及动脉瘤样骨囊肿病例,则良性骨肿瘤及肿瘤样病变的最低、最高和整体ADC值分别为(1.11±0.31)×10-3mm2/s、(1.88±0.49)×10-3mm2/s和(1.45±0.35)×10-3mm2/s,与恶性骨肿瘤比较差异无统计学意义(t值分别为1.728、0.964、2.012,P值均>0.05).结论 ADC值不能鉴别良、恶性骨肿瘤及肿瘤样病变.     

MR perfusion imaging in proliferative angiopathy

Seizures, which may be the main expression of cerebral arteriovenous malformations (CAVM) can be difficult to control medically. Our goal was to use perfusion-weighted imaging (PWI) in correlation with clinical data to detect abnormal areas of the cerebrum related to a particular type of CAVM (proliferative angiopathy) and to study the pathophysiology. We use PWI, with a bolus injection of contrast medium, to investigate seven patients with proliferative angiopathy and fits producing language disturbance. Perfusion parameters were calculated using the first-pass moment theory. Five patients had perimalformative and/or contralateral abnormal areas with relative hyperperfusion (cerebral blood volume +20.7±16.2%, blood flow 92.5±68.8 ml/min/100 g). Areas of hypoperfusion and venous congestion were detected in two patients. One patient who underwent MRI after a severe focal deficit had no significant haemodynamic abnormality.     

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。     

幕上脑内肿瘤磁共振灌注成像的初步研究

目的 探讨磁共振灌注成像(PWI)在幕上脑内肿瘤中的诊断价值。资料与方法 56例幕上脑内肿瘤,行双倍剂量PWI后,计算病灶的相对局部脑血流容积(rrCBV)。结果 Ⅲ、Ⅳ级星形细胞瘤和Ⅱ级少突胶质瘤为高灌注,而Ⅱ级星形细胞瘤和淋巴瘤为低灌注,低、高灌注肿瘤的rrCBV间差异显著,而高灌注肿瘤之间和低灌注肿瘤之间无差异。肺癌和乳腺癌脑转移瘤的rrCBV高于消化道癌肿脑转移瘤。结论 PWI在幕上脑内肿瘤的鉴别诊断、星形细胞瘤的分级和寻找转移瘤原发灶方面具有一定的价值。     

高b值MR扩散加权成像在乳腺良恶性病变诊断中的应用价值

目的 评价高b值MR DWI及ADC值在乳腺良恶性病变诊断中的应用价值.方法 165例患者在行乳腺MR动态增强扫描前行不同b值(分别为500、1500 s/mm2)的DWI扫描,对171个怀疑或高度怀疑恶性病变者行回顾性分析.以正常乳腺组织为参考基准,选择增强图像中异常强化的高信号病变,同时在高b值(b= 1500 s/mm2)DWI中视觉判定是高信号的病变定义为恶性病变阳性结果,否则为良性病变阴性结果.对其中111个DWI视觉判定阳性结果的病变计算ADC值.依据全部病变穿刺活检病理诊断结果,应用Fisher精确检验和Wilcoxon秩和检验对比分析高b值DWI视觉评估中恶性和良性病变的阳性和阴性病灶数,以ADC值=1.13×10-3 mm2/s作为临界值,计算诊断的特异度和敏感度.结果 乳腺病变穿刺活检病理证实的171个乳腺病变中,91个恶性病变,80个良性病变.高b值DWI视觉评估,139个阳性结果中,恶性病变83个,良性病变56个;32个阴性结果中,良性病变24个,恶性病变8个(非肿块性导管原位癌),差异有统计学意义(P＜0.01).所有浸润性癌和肿块样导管原位癌(DCIS)在DWI视觉判定中为阳性,8例非肿块性DCIS判定为假阴性,总体的敏感度为91.2％ (83/91),特异性为30.0％ (24/80).110个肿块样病变和1个局灶性病变DWI视觉评估阳性结果的病变中,63个恶性病变平均ADC值为(0.73±0.24)×10-3 mm2/s,48个良性病变平均ADC值为(1.19±0.42)×10-3mm2/s,差异有统计学意义(Z=5.818,P＜0.01).以ADC值=1.13×10-3mm2/s作为临界值时,61个恶性病变为阳性结果,2个黏液癌为假阴性结果;27个良性病变为阴性结果,21个良性病变为假阳性,诊断敏感度是96.8％(61/63),特异度为56.2％ (27/48).结论 高b值DWI及ADC值对乳腺良恶性病变的鉴别诊断有一定的作用,但在诊断非肿块性乳腺病变时仍需慎重.     

脑室脑膜瘤的MRI影像表现及其病理基础

目的：探讨脑室脑膜瘤的影像学表现及其病理基础,提高诊断准确性。方法回顾性分析手术病理证实的20例脑室脑膜瘤的M RI表现,总结其影像特征及病理基础。结果脑室脑膜瘤以纤维型为主;DWI多呈高信号;肿瘤多数位于侧脑室三角区,1例位于双侧脑室及三脑室;肿瘤边界清晰,多数为实性分叶状肿块,1例明显囊变;增强扫描强化明显;均有脑室的扩大;瘤周水肿以轻度为主。结论脑室脑膜瘤的M RI表现有一定的特征性,结合临床资料,可提高诊断准确率。