良、恶性胰腺实性假乳头状瘤的CT和MRI诊断要点分析

目的分析并归纳良、恶性胰腺实性假乳头状瘤（SPT）的CT和MRI特征性诊断要点,以期提高其诊断准确率。方法回顾性分析经手术病理证实的38例胰腺良性SPT和10例实性假乳头状癌（SPC）,分析其CT和MRI征象并归纳特征性诊断要点。结果38例良性SPT均存在完整包膜,表现为T1、T2低信号,增强后呈延迟强化;10例SPC中9例包膜局部显示不清、不完整。18例良性SPT和6例SPC钙化均呈点状、结节状或弧线状。11例良性SPT和6例SPC瘤内出血,CT平扫呈稍高密度,T1呈稍高信号,T2呈稍低信号。7例良性SPT和5例SPC胰管扩张,胰管呈管状或串珠样扩张。38例良性SPT均未见周围血管受侵犯;4例SPC侵犯周围血管,血管壁表现为模糊。38例良性SPT均未见周围组织受侵犯;5例SPC侵犯周围组织,表现为瘤-组织边缘模糊,局部包膜不完整。结论包膜、钙化、瘤内出血、胰管扩张、侵犯血管及周围组织为胰腺良性SPT和SPC具有特征性的CT和MRI征象,其中,包膜、是否侵犯血管及周围组织可作为两者的鉴别诊断要点。     

全身DWI的正常表现及在转移瘤筛查中的临床应用

目的:探讨磁共振全身扩散加权成像(全身DWI)的正常表现及在转移瘤筛查中的应用价值。方法:20例健康志愿者及25例疑似或确诊恶性肿瘤患者行磁共振全身扩散加权成像,其中11例肿瘤患者同时行PET/CT检查。全身DWI应用STIR抑制背景信号,从头顶至股骨上分段无间隔扫描,共覆盖1080～1440mm,b值取0及600s/mm2。结果:在健康志愿者的全身DWI像上,脑实质、涎腺、椎间盘、脊髓、脾脏、肾脏和前列腺、睾丸、子宫、卵巢等脏器呈高信号,其余脏器及骨骼呈等信号。原发恶性肿瘤及转移灶在全身DWI呈明显高信号,对比度高于常规MRI序列。25例患者全身DWI共检出70处高信号病灶,包括原发恶性肿瘤及转移灶68处,良性病灶2处,显示率为98.6%。11例PET/CT检查共有20处阳性显像,原发恶性肿瘤及转移灶16处,良性病灶4处,显示率100%。结论:磁共振全身扩散加权成像一次检查可完成从头顶至股骨上段的大范围成像,对恶性肿瘤原发灶及转移灶有较高的显示率,可以作为恶性肿瘤患者原发及转移灶筛查的有力工具之一。     

Diffusion-weighted magnetic resonance imaging of focal hepatic nodules in an experimental hepatocellular carcinoma rat model

RATIONALE AND OBJECTIVES: We sought to investigate the value of diffusion-weighted MR imaging in evaluating focal hepatic nodules in an experimental hepatocellular carcinoma (HCC) rat model. MATERIALS AND METHODS: Forty rats with chemically induced primary hepatic nodules ranging pathologically from regenerative nodules (RNs) to dysplastic nodules (DNs) to HCC were examined with diffusion-weighted imaging. The apparent diffusion coefficient (ADC) values of hepatic nodular lesions were calculated. Tukey's HSD post hoc test was used to compare the difference in ADC values between different hepatic nodular lesions. RESULTS: Eight RNs, 16 DNs, 7 well-differentiated HCCs (HCCwell), 11 moderately differentiated HCCs (HCCmod), and 14 poorly differentiated HCCs (HCCpoor) were evaluated. There was no significant difference between RNs and DNs (P > 0.05). Although the ADC values of HCCwell were slightly lower than those of DNs, there was no significant difference between them (P > 0.05). The ADC values of HCCmod and HCCpoor were significantly higher (P < 0.05) than those of other nodules, and no significant difference was seen between HCCmod and HCCpoor (P > 0.05). CONCLUSION: Diffusion-weighted magnetic resonance imaging can be useful in characterizing focal hepatic nodular lesions, but ADC values cannot be used efficiently to distinguish HCCwell from DNs.     

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.     

Computed diffusion-weighted MR imaging for visualization of pancreatic adenocarcinoma: Comparison with acquired diffusion-weighted imaging

ObjectiveTo assess the feasibility of computed diffusion-weighted imaging (cDWI) in comparison with directly acquired DWI for visualizing pancreatic adenocarcinomas.Materials and methodsPatients with pancreatic adenocarcinoma underwent DWI at b-values of 0, 1000 (DWI₁₀₀₀), 1500 (DWI₁₅₀₀) and 2000 (DWI₂₀₀₀) s/mm². From DWIs at b-values of 0 and 1000 s/mm², we generated cDWIs at b-values of 1500 (cDWI₁₅₀₀) and 2000 (cDWI₂₀₀₀) s/mm². DWI findings of pancreatic adenocarcinomas (clear hyperintensity; hyperintensity with an unclear distal border; and isointensity), the image quality and the tumor to pancreas contrast ratio (CR) were compared between directly acquired DWI and cDWI.ResultsAmong the 63 included patients, clear hyperintense tumors were seen in 35 on DWI₁₀₀₀, 50 on DWI₁₅₀₀, 50 on cDWI₁₅₀₀, 53 on DWI₂₀₀₀ and 44 on cDWI₂₀₀₀. Incidence of clear hyperintense tumors was significantly higher on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P = 0.013). There was no significant difference in the incidence of clear hyperintense tumors between DWI₁₅₀₀ and cDWI₁₅₀₀ (P > 0.999), but a lower incidence was seen on cDWI₂₀₀₀ than on DWI₂₀₀₀ (P = 0.028). Image quality was lower on cDWI than on DWI at b-values of 1500 (P = 0.002) and 2000 s/mm² (P < 0.001). The tumor to distal pancreas CR was significantly higher on cDWI₂₀₀₀ than on cDWI₁₅₀₀ (P < 0.001), and on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P < 0.001). The cDWI showed a significantly higher tumor to distal pancreas CR than DWI at b-values of 1500 (P = 0.004) and 2000 s/mm² (P < 0.001).ConclusionscDWI₁₅₀₀ generated from b-values of 0 and 1000 s/mm² should be considered more effective than DWI₁₀₀₀ and at least as effective as DWI₁₅₀₀.     

Various diffusion magnetic resonance imaging techniques for pancreatic cancer

Pancreatic cancer is one of the most common malignant tumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging (MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging (DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed.     

Diffusion-weighted magnetic resonance imaging of pancreas tumours

The purpose of this study was to evaluate the accuracy of diffusion-weighted imaging (DWI) in diagnosis of pancreas cancer, to compare DWI with a conventional comprehensive MRI (MRI-c) and to analyse apparent diffusion coefficient (ADC) values of lesions. Thirty-six patients with pancreatic lesions (12 malignant and 24 benign) and 39 patients without lesions were included. MRI-c and DWI (free breathing, b values 0 and 500 s/mm²) were performed prospectively and consecutively in a 1.5-T system. The analysis was retrospectively performed blinded by two radiologists in consensus. The sensitivity, specificity, accuracy, and positive and negative predictive values of DWI and MRI-c were 92, 97, 96, 85, 98% and 100, 97, 97, 86, 100%, respectively. Mean ADC values of malignant lesions were significantly lower than those of benign lesions. DWI has a similar accuracy to MRI-c in diagnosis of pancreas cancer.     

胰腺实性假乳头状瘤影像学表现

目的 探讨胰腺实性假乳头状瘤的CT及磁共振成像(MRI)表现,提高该疾病的影像正确诊断率.方法 回顾性分析9例经本院手术病理证实的胰腺实性假乳头状瘤的影像表现,术前1例仅接受CT检查,6例仅接受MRI检查,2例同时接受CT及MRI检查.结果 本组9例病例均为单发病灶,大多数类圆形、椭圆形.胰头颈部2例,胰体尾部7例.直...     

MR在乳腺肿瘤中的应用

随着MR成像技术的不断发展，MRI诊断乳腺疾病的敏感性有了很大的提高。近年来MRS及MR引导的乳腺定向活检技术的临床应用，进一步提高了腿诊断乳腺疾病的特异性。就近年文献中有关乳腺肿瘤的腿应用予以综述。     

磁共振扩散加权成像在胰腺癌诊断中的价值

目的探讨磁共振扩散加权成像在胰腺癌诊断中的价值。方法选择2012年1月～2013年1月间临床可疑胰腺癌患者75例,对这些患者进行磁共振扩散加权成像检查,将检查结果与病理结果比较,明确两者之间的相关性,同时确定磁共振扩散加权成像在胰腺癌诊断中的敏感性、特异性。结果75例可疑胰腺癌患者经DWI检查,诊断为胰腺癌38例,与病理结果比较,两者存在相关性（r=23．12,P=-0．00〈0．05）,且相关系数为0．56。同时与病理结果比较DWI诊断胰腺癌的敏感性为73．33％,特异性为83．33％,阳性预测值和阴性预测值分别为86．84％和67．57％。结论磁共振扩散加权成像作为无创检查手段能够准确地对胰腺占位做出定性诊断,在临床应用价值较大。     

Negative scintigraphy with positive magnetic resonance imaging in bone metastases

We report three patients with known primary tumor in whom radionuclide skeletal imaging for metastatic disease was normal with or without clinical symptomatology referable to this area. Magnetic resonance imaging (MRI) of the spine demonstrated focal areas of abnormal signal intensity in the vertebral bodies of these patients. In all three patients, biopsy confirmed metastatic disease. All the patients received radiation or chemotherapy depending upon the etiology. These preliminary data suggest that MR imaging may be useful in evaluating patients with known primary tumor in whom clinical suspicion persists despite a negative radionuclide bone scan.     

Ring-shaped lateral ventricular nodules: an incidental finding on brain magnetic resonance imaging

Introduction  We have occasionally seen ring-shaped lateral ventricular nodules <1 cm in diameter during routine brain magnetic resonance imaging (MRI). We investigated retrospectively clinical and MRI findings of the nodules. Materials and methods  Review of radiological records was performed for 39,607 patients who underwent brain MRI between January 2001 and April 2008. Nodules were assessed for number, location, shape, and signal intensity, which was determined based on the range of signal intensity from gray to white matter on T1- and T2-weighted imaging. Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI), contrast enhancement characteristics, and serial MRI changes of nodules were assessed when available. Results  Nine of 39,607 patients (0.023%) showed the nodules. No symptoms associated with the nodules. Among the nine patients, 11 nodules were identified (one nodule in seven patients (77.8%) and two nodules in two patients (22.2%)). Location was limited to the roof of the body for six nodules (54.5%) and the frontal horn for five patients (45.5%). All nodules (100%) were round and isointense on T1- and T2-weighted imaging. On FLAIR imaging of eight nodules, six (75%) were hyperintense, and two (25%) were isointense. On DWI of seven nodules, all nodules (100%) were isointense. None of seven nodules (0%) examined using postcontrast MRI showed enhancement. None of eight nodules (0%) examined using serial MRI (range, 4–60 months) showed changes in morphology over time. Conclusion  These nodules were incidentally encountered and shared similar MRI features. Although pathological confirmation was lacking in our cases, these nodules may be of nonaggressive nature.     

磁共振成像技术对胰腺导管内乳头状黏液瘤的诊断价值

目的探讨胰腺导管内乳头状黏液瘤的MRI影像学特点,以提高该病的诊断准确率。方法搜集12例经手术证实的胰腺导管内乳头状黏液瘤患者的临床及影像学资料,回顾性分析主胰管型和分支胰管型的MRI表现。结果研究证实,12例中有主胰管型3例和分支胰管型9例。主胰管型MRI表现为主胰管节段性或弥漫性扩张,可伴有胰腺实质的萎缩;分支胰管型MRI表现为单房或多房型囊性病变,并与主胰管相通。结论 MRI对胰腺导管内乳头状黏液瘤是一种无创、有效的诊断方法,有助于提高该病的诊断准确率。     

肾脏MR扩散峰度成像研究进展

MR扩散峰度成像（DKI）基于多项式模型,能够量化组织中水分子的扩散运动与自由高斯运动的偏差。DKI技术可以定量评价组织微环境的复杂性和异质性,近年来已用于评价肾脏功能及相关疾病,在肾脏肿瘤的分级,以及在梗阻性肾病、糖尿病肾病、高尿酸血症肾病等常见疾病的早期诊断中具有一定的应用价值。就DKI成像原理及在正常肾脏和肾脏常见疾病中的研究进展予以综述。     

大脑胶质瘤病磁共振成像结合磁共振波谱成像的诊断价值

目的：探讨磁共振成像（MRI）结合磁共振波谱成像（MRS）对大脑胶质瘤病的诊断价值。方法对15例经活体组织检查或手术病理证实的大脑胶质瘤病患者的临床表现及MRI平扫、增强,MRS影像学资料进行回顾性分析。MRI常规行T1WI、T2WI及FLAIR序列,采用时间飞跃法（TOF）的磁共振血管成像（MRA）,T1WI增强扫描。氢质子MRS采用单体素STEAM序列,并分析N-乙酰天门冬氨酸（NAA）、肌酸（Cr）、胆碱复合物（Cho）等物质峰值改变。结果所有病例均侵犯2个或2个以上脑叶,以颞叶、枕叶、胼胝体、基底节和丘脑等部位侵犯受累常见。病变区T1WI呈低或等低信号、T2WI呈高或混杂高信号、FLAIR上为高信号,未见明显坏死、钙化,受累区域脑组织肿胀,占位效应轻。注射钆喷酸葡胺增强扫描示10例无明显强化、3例斑片状强化、1例结节状强化、1例线状轻度强化。病变区域MRS表现为不同程度NAA降低,NAA/Cr比值降低;Cho上升,Cho/Cr和Cho/NAA的比值上升。结论 MRI结合MRS对大脑胶质瘤病的诊断及鉴别诊断具有临床价值,是目前诊断大脑胶质瘤病的首选影像学方法。     

胰腺疾病的MR胰胆管成像征象的定量分析

目的　研究不同胰腺疾病的MR胰胆管成像 (MRCP)特征 ,探讨特征性表现及MRCP对胰腺疾病的诊断价值。方法　对 111例临床怀疑胰腺疾病的患者进行MRCP检查。MRCP扫描序列包括 :厚层快速自旋回波 (TSE)序列和薄层半傅立叶采集单次激发快速自旋回波 (HASTE)序列 ,其中胰腺癌 4 6例 ,慢性胰腺炎 39例 ,壶腹周围癌 2 3例 ,胆总管结石 3例。结果　 (1) 37例胰腺癌、2 4例慢性胰腺炎和 12壶腹周围癌出现胰管改变 ,其中 33例胰腺癌、0例慢性胰腺炎和 12例壶腹周围癌出现胰管平滑扩张并中断 ,经统计学分析 χ2 =5 7 911,P <0 0 1;2例胰腺癌、2 3例慢性胰腺炎和 0例壶腹周围癌出现胰管不规则扩张且贯通病变区 ,经统计学分析 χ2 =6 0 343,P <0 0 1。 (2 ) 2 9例胰腺癌、10例慢性胰腺炎和 2 3例壶腹周围癌出现胆总管扩张 ,其中 2 9例胰腺癌、1例慢性胰腺炎和 2 3例壶腹周围癌出现胆总管扩张后截断 ,经统计学分析 ,χ2 =6 1 2 17,P <0 0 1。 (3) 2 9例胰腺癌、1例慢性胰腺炎和 12例壶腹周围癌出现双管征 ,经统计学分析 ,χ2 =34 6 5 4 ,P <0 0 1。 (4 ) 2 4例慢性胰腺炎、0例胰腺癌和 0例壶腹周围癌出现假性囊肿 ,经统计学分析 ,χ2 =5 4 5 93,P <0 0 1。结论　不同胰腺疾病有其相对应的特征性表现 ,MRCP能够显     

儿童心脏良性肿瘤的CMR影像特征分析

目的 研究儿童心脏良性肿瘤的心脏MR（CMR）特征及其对儿童良性肿瘤的诊断价值。方法 回顾性收集2006年9月-2018年3月于我院进行CMR检查的心脏肿瘤病例资料,共38例心脏良性肿瘤患儿纳入研究,其中男21例,女17例,年龄0.2~153.3个月,中位年龄13个月。分析各病理类型肿瘤在CMR上的特征,包括累及部位、大小、信号特点、血流动力学改变等,以及是否伴发心包和胸腔积液。通过与病理结果对照,计算CMR对心脏良性肿瘤诊断的敏感度和准确度。结果 肿瘤累及心肌、心腔、心包、心室流出道及纵隔,形态大小不一,临床症状与肿瘤发生部位有一定相关性而不具有特异性,但各类肿瘤具有一定的影像特征。所有的心脏肿瘤均被CMR清晰显示,CMR的诊断与病理结果相符的有32例,诊断的敏感度及准确度分别为100%（38/38）和84.21%（32/38）。结论 CMR能够同时提供心脏良性肿瘤的形态学特征及组织学信号特征,对心脏良性肿瘤诊断的敏感性及准确性均较高,是评估心脏肿瘤的重要检查方法。     

动态增强MR成像在胰腺疾病中的应用

胰腺微循环变化及血流动力学改变在胰腺的多种疾病发生发展过程中起着至关重要的作用,而动态增强MR成像（DCE-MRI）具有评估组织器官微循环及血流灌注状态的能力,因此有关DCE-MRI灌注参数在胰腺疾病的诊断、鉴别诊断及疗效评估中的作用是当前研究的热点。就DCE-MRI成像原理及其在正常胰腺及胰腺疾病中的应用现状予以综述。     

Role of magnetic resonance imaging in distinguishing fungal from nonfungal multiple brain abscesses

Cladophialophora bantiana is a neurotropic dematiaceous fungus known for affecting immunocompromised and immunocompetent hosts. We report a case of 24 year old immunocompetent male presenting with headache, fever and vomiting. MRI was suggestive of multiple fungal brain abscesses. He underwent total excision of abscesses. Pus culture was suggestive of brain abscess caused by C. bantiana. We report a culture proven case of C. bantiana emphasizing on specific MRI features which are critical in differentiating fungal from nonfungal brain abscesses.     

缩窄性心包炎磁共振成像的诊断研究

目的评价ＭＲＩ对缩窄性心包炎的诊断和鉴别诊断价值及其限度。材料与方法２６例经临床资料、心电图、Ｘ线和（或）手术证实的缩窄性心包炎患者，行心电图门控ＳＥ和ＧＥ电影ＭＲＩ扫描，ＭＲＩ所见与３０例正常成人志愿者行对比分析。结果缩窄性心包炎的主要ＭＲＩ征象有：心包脏壁层界限不清，呈不规则增厚（厚度＞４ｍｍ），以右心房室侧多见；增厚的心包呈中等信号或中等度低信号，内部信号不均，其中可有斑状极低信号或高信号；室间隔僵直，心室内径缩小，室壁运动减弱；右心房扩大，上下腔静脉扩张，少数病例左心房扩大，肺静脉扩张；可合并房室瓣少至中等量返流。结论ＭＲＩ很容易确定缩窄性心包炎的心包增厚，具有诊断和鉴别诊断的价值，但其价格昂贵、对钙化不敏感为其主要限度。