菲立磁增强MRI在肝脏局灶性病变诊断中的价值

目的 评价菲立磁增强MRI在肝脏实性占位性病变诊断中的应用价值。材料与方法 对21例怀疑有肝脏局灶性占位病变患者行MR平行及菲立磁增强MRI检查。扫描序列包括频率选择脂肪抑制及非脂肪抑制ASTE T2WI、True FISP T2WI、频率选择脂肪抑制FLASH T1WI。比较增强前后T2WI及T2WI病灶及肝脏的信噪比（SNR）及对比噪声比（CNR）;观察增强前后病灶数量及形态;结合MR平扫及增强MRI表现进行定性诊断。结果 菲立磁增强T2WI及T2WI肝脏信号强度较平扫明显下降,病灶与肝脏的CNR较平扫明显提高,差异具有统计学意义。结论 菲立磁增强T2WI及T2WI可明显提高肝脏实性占位性病灶的检出率。菲立磁增强T1WI在脏局灶性病变的定性诊断中具有潜在价值,有待于进一步开发与研究。     

网状内皮系统特异性MR对比剂菲立磁(Feridex)的临床初步应用

目的：评价菲立磁在MR检查中的诊断价值和安全性。方法：对17例肝、脾、淋巴结病变患者进行常规MR检查和菲立磁增强扫描,观察、分析、增强前后T1WI、T2WI图像上肝、脾、淋巴结的信号变化及病灶数目,以及不良反应。结果;菲立磁明显降低,肝、脾组织和含吞噬细胞的良性病变的信号强度,不影响未含吞噬细胞病灶的信号强度,同时具有早期缩短T1弛豫时间,不良反应少。结论：菲立磁在检测肝、脾局灶性病变中,敏感性高,具有一定的鉴别诊断价值。且安全。     

为什么部分肝脏局灶病变在超顺磁氧化铁增强T1WI上呈现高信号

目的:探讨肝脏病变在SPIO增强扫描T1WI上呈现高信号的机制.方法:肝脏局灶病变39例(56个病灶),其中33个恶性病灶(肝细胞癌10个、转移瘤21个、胆管细胞癌2个)和良性病灶23个(海绵状血管瘤9个,肝囊肿14个).平扫序列包括SE T1WI、FSPGR T1WI及FSE T2WI.SPIO(菲立磁)增强扫描序列包括FSE T2WI、SE T1WI(TE值分别为8 ms、20 ms)和 FSPGR T1WI(TE值分别为1.5 ms、4.2 ms).分析不同序列图像上病灶及肝实质的的信号变化.结果:在SPIO增强T1WI上,随着TE的延长,肝实质信号降低,肝内局灶病变信号相对增高.在SPIO增强长TE T1WI上,大部分恶性病灶及全部血管瘤呈相对高信号.结论:在SPIO增强T1WI上,SPIO对肝实质的T2*效应可能是部分局灶病变呈高信号的主要原因.     

菲立磁增强MRI检测肝脏局灶性病变的初步报告

目的 探讨菲立磁增强磁共振在肝脏局灶性病变中的诊断价值。材料与方法 对21例怀疑肝脏肿瘤的患者进行常规肝脏平扫和菲立磁增强扫描,分析增强前后T2WI检测病灶数目以及肝脏、病灶、脾脏信号强度的变化。结果 菲立磁增强明显降低正常肝脏的信号强度、而病灶的信号强度无明显变化,病灶－肝脏的信号强度比增加;菲立磁增强可清晰地显示病变并可发现更多的病变。结论 菲立磁增强在检测肝脏局灶性病变中敏感性高。     

周边廓清:局灶性肝病变钆增强MRI的一种恶性征象

作者把肝肿块性病变周边廓清征定义为:在延迟增强MRI时病灶周边出现相对于病灶中心的低信号强度环,用以评价此征象对鉴别良恶性肝局灶性病变的意义。102例肝脏肿块性病变患者中49例为恶性、53例为良性。1.5T MR机,行非增强T_1WI(SE500/15)、T_2WI(SE2300/15,90)。梯度回波成象(GRE)和动态钆增强MRI检查,层厚8mm,层距2mm。     

超顺磁性氧化铁诊断肝脏小病灶的临床应用价值初探

目的：探讨超顺磁性氧化铁（商品名为菲立磁,Feridex)对肝脏小病灶的临床应用价值,以及滴注后的最佳扫描时间。方法：17例经B超或CT检查发现肝脏内小病灶患者,经常规MR平扫和增强扫描1－3d后,经静脉滴注菲立 （0.05ml/kg),并于0.5,3.6h后进行扫描。主观目测菲立磁增强后肝脏小病灶的显示情况,定量分析菲立磁增强后肝脏信号下降情况。结果;菲立磁增强后扫描可显著肝脏内直径小于1cm的病灶21个,明显多于常规MR检查（8个）。菲立磁应用后小肝癌和容易与肝癌混淆的局灶性结节增生和再生结节信号变化明显不同。菲立磁增强后扫描,肝脏T2WI,T1WI信号均较增强前下降（P＜0．01）,滴注菲立磁后0.5,3,6h扫描,T2WI各时间点的脏脏信号下降统计学上差异无显著性意义（P＞0．05）。结论：菲立磁能显著提高肝脏小病灶的检出率,而且对肝脏小病灶的鉴别诊断可提供有利的依据。     

几种肝脏病变的MRI菲立磁增强表现及诊断价值

目的:探讨菲立磁(SPIO)增强在肝脏病变中的诊断价值。方法:16例患者行SPIO增强的MRI检查,其中6例为海绵状血管瘤,不均匀脂肪肝4例,肝细胞癌(HCC)3例,局灶结节增生(FNH)、肝腺瘤及肝转移瘤各1例。结果:与MRI平扫相比,肝内海绵状血管瘤在SPIO增强后的T1WI上信号明显增高,而在T2WI上信号强度有轻度下降;在不均匀脂肪肝的病例中,增强后兴趣区与周围肝组织的信号强度对比关系延续了增强前的表现;肝腺瘤和FNH在增强后的T2WI上有明显的信号强度下降:HCC在增强后的T2WI上常无明显信号下降,而在T1WI上却有轻度信号升高;转移瘤在T2WI上无信号下降。结论:SPIO强化MRI对肝内病变的良恶性鉴别诊断有一定的帮助。     

菲立磁增强MRI检测肝脏占位病变与三期动态增强CT扫描的比较研究

目的　比较菲立磁增强MRI和增强CT扫描在肝脏实性占位病变检测中的应用价值。方法　对 18例肝内局灶性占位患者行MR平扫及菲立磁增强扫描。观察肝脏与病灶信号强度变化 ,形态及数目 ,比较增强前后T2 WI病灶及肝脏的信噪比 (SNR)及对比噪声比 (CNR) ,做出MRI定性诊断 ,并与增强CT扫描诊断进行比较。其中肝细胞肝癌 4例 ,复发性肝癌 4例 ,转移瘤 4例 ,肝血管瘤 6例。结果　菲立磁增强明显降低正常肝组织信号强度 ,而恶性肿瘤的信号强度无强化 ,病灶—肝脏信噪比增加可清晰显示病变 ,并发现新病灶。肝血管瘤的血池效应与增强CT扫描比较有鉴别诊断意义。结论　做为增强CT扫描和Gd -DTPAMR增强的补充方法 ,SPIO增强MRI对肝脏占位病变的显示 ,小病灶发现和定性诊断中有重要的临床意义     

家兔超急性期放射性肝损伤MRI表现与病理对照研究

目的　探讨超急性期放射性肝损伤MRI表现及其病理基础 ,评估MRI平扫及菲立磁增强扫描检出放射性肝损伤的时间效能。材料与方法　 18只家兔随机分成 3组后均给予 4 0Gy单次X线半肝照射 ,第 1组于照射后第1d、第 2、3组分别于照射后第 2、3d行肝区MRITSE T2 WI及TSE T1WI两个序列的平扫及菲立磁增强扫描 ,同时取材做组织学检查。对MRI表现与病理组织学检查结果进行对照分析。结果　所有家兔T2 WI及T1WI平扫、T1WI菲立磁增强扫描肝组织信号强度均未发现变化。T2 WI菲立磁增强扫描对放射性肝损伤的检出时间为照射后第 3d(P <0 .0 1) ,表现为肝组织信号强度受照区与非受照区均较T2 WI平扫时降低 ,但受照区肝组织信号强度较非受照区高 ,两者间可见分界线。所有家兔受照区肝组织在光镜下未见明确组织水肿、纤维化及炎症细胞浸润等病理征象 ,但其单位视野面积内含有SPIO颗粒的Kupffer细胞数在照射后第 3d明显低于非受照区 (P <0 .0 1)。电镜下 ,照射后第 3d的受照区肝细胞及Kupffer细胞内见线粒体明显肿胀伴局部空泡样变。结论　T2 WI菲立磁增强扫描在照射后短时间内 (照射后第 3d)即可检出超急性期放射性肝损伤 ,并能提供直观、精细的影像学依据     

动态增强容积内插序列在肝脏占位性病变的临床应用价值

目的:评价MRI三维动态增强容积内插序列在肝脏局灶性病变的临床应用价值.方法:91例肝脏占位性病变患者进行常规MR T1WI和T2WI扫描后,采用三维扰相梯度序列行屏气全肝3期动态增强扫描并进行图像重组,观察病灶的增强特点,并对肝动脉的显示程度进行分级.结果:91例中原发性肝癌17例,肝血管瘤24例,肝转移性肿瘤16例,局灶性结节增生2例,肝脓肿11例,肝囊肿21例.肝动脉显示为2级86例94.5%,1级3例3.3%,0级2例2.2%.结论:MR 动态增强容积内插技术可以获得高质量的图像(尤其是动脉期),有利于肝脏局灶性病变的定性、定位诊断和指导临床治疗.     

MRI诊断含脂质肝脏肿瘤的价值

目的:评估MRI诊断含脂质肝脏肿瘤的价值.材料和方法:回顾性分析34例含脂质肝脏肿瘤的MRI表现和术前或穿刺前诊断,并与病理对照.结果:T1WI 32例呈高信号、2例低信号,T2WI 32例呈高信号、1例等信号、1例低信号.用脂肪抑制后,15例肝细胞癌(HCC)、7例血管平滑肌脂肪瘤(HAML)、1例肝腺瘤和1个局灶结节性增生(FNH)T1WI的高信号完全消失,1例不典型腺瘤样增生结节局灶癌变和1例HAML出血囊变T1WI 高信号大部分消失,6例肝腺瘤和1个FNH病灶T1WI高信号无变化 .26例血供丰富,4例血供不丰富.14例HCC、2例腺瘤、7例HAML和1例FNH诊断正确,2例HAML诊断为良性肿瘤.结论:MRI能显示含脂质肝脏肿瘤的特征性表现,并正确诊断多数这类肿瘤.     

菲立磁增强MRI对局灶性肝病的诊断价值:与螺旋CT对比的ROC曲线分析

目的 :对比分析菲立磁增强扫描与螺旋CT增强扫描对局灶性肝病的诊断价值。方法 :收集经本院完成螺旋CT增强扫描及菲立磁增强MRI扫描且临床、手术病理证实局灶性肝病 2 6例 5 7个病灶 ,采用分组盲法ROC曲线分析对比评价菲立磁增强MRI与螺旋CT增强扫描对局灶性肝病的诊断价值。结果 :联合分析平扫 +菲立磁增强MRI对病灶检出最好 ,与其它三组比较有显著性差异。对病灶定性 ,平扫 +菲立磁增强MRI组ROC曲线下面积Az 值最大为 0 92 6 0 ,准确性为 86 .8% ,差异有显著性 ,P <0 .0 5。螺旋CT增强扫描、MRI平扫及单独分析菲立磁MRI等三种方法之间差异无显著性 (P >0 .0 5 )。结论 :菲立磁增强MRI肝成像无论病灶的检出及定性诊断价值均高于螺旋CT增强扫描。联合分析平扫+菲立磁MRI较单独分析SPIO能明显改善病灶的检出能力及定性诊断能力。     

Percentage of signal intensity loss for characterisation of focal liver lesions in patients with chronic liver disease using ferucarbotran-enhanced MRI

The purpose of this study was to determine the percentage of signal intensity loss (PSIL) threshold for the characterisation of focal liver lesions among patients with chronic liver disease. 55 nodules in 49 patients with chronic liver disease who underwent ferucarbotran-enhanced MR studies were included. Among the 49 patients, 40 had liver cirrhosis and 9 had chronic hepatitis. 8 haemangiomas, 3 focal nodular hyperplasia, 9 dysplastic nodules and 12 well, 19 moderately and 4 poorly differentiated hepatocellular carcinomas (HCCs) were revealed. The PSIL, signal-to-noise ratio and contrast-to-noise ratio of each lesion type were calculated. The diagnostic performance of PSIL on ferucarbotran-enhanced T₂ weighted images (PSIL_T2WI) and T₂ weighted fat-suppression images (PSIL_FS-T2WI) that characterised hepatic tumours was compared with receiver operating characteristic (ROC) analysis. Using ROC analysis, the diagnostic performance of PSIL_FS-T2WI was superior to that of PSIL_T2WI (p = 0.01). The mean PSIL_FS-T2WI of the benign lesions was significantly higher than that of HCC (p<0.001), and the mean PSIL_FS-T2WI of well-differentiated HCC was significantly higher than that of moderately/poorly differentiated HCCs (p = 0.001). With a PSIL_FS-T2WI threshold of 40% in lesions characterising ferucarbotran-enhanced FS-T2WI, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 88.6%, 95%, 90.9%, 96.9% and 82.6%, respectively. In conclusion, with ferucarbotran-enhanced FS-T2WI, a PSIL_FS-T2WI threshold of 40% for characterising focal liver nodules among patients with chronic liver disease is recommended. It is useful for distinguishing HCC from benign nodules.Nodular lesions against a background of cirrhosis are diagnostically challenging in daily practice. Hepatocellular carcinoma (HCC) develops by means of a multistep dedifferentiation process that progresses from regenerative nodule to dysplastic nodule and then to HCC [1]. Early detection of HCC is important in improving patient outcome and decision making in therapeutic strategies. Asahina et al [2] reported that the assessment of Kupffer cells by ferumoxide-enhanced MRI is beneficial for accurately diagnosing HCCs that are characterised as borderline or early-stage HCCs based on their haemodynamic profile.Ferucarbotran (Resovist, Schering, Germany), a superparamagnetic iron oxide (SPIO), is a liver-specific particulate MRI contrast agent that is primarily taken up by the Kupffer cells of the liver. The uptake-clustered particles can produce a susceptibility effect and cause loss of the signal intensity on post-contrast T₂ weighted images (T2WI) [3]. Imai et al [4] reported that SPIO-enhanced MRI might reflect Kupffer cell numbers in HCCs and was useful for estimation of histological grading in HCCs. However, it is difficult to detect borderline lesions and early-stage HCCs such as dysplastic nodules and well-differentiated HCCs (wHCCs) using SPIO-enhanced MRI because of SPIO uptake by the retained Kupffer cell activity in the nodules [5, 6].Namkung et al [7] have reported that a percentage of signal intensity loss (PSIL) threshold of 25% is effective for the differentiation of benign and malignant hepatic lesions. HCC tends to occur in patients with chronic liver disease such as chronic hepatitis, liver cirrhosis and alcoholism [8]. Could the threshold also be effective in detection of HCC and lesion characterisation for these patients? To our knowledge, the value of PSIL threshold in characterisation of focal liver lesions among high-risk patients has not been elucidated properly. The purpose of our study was to determine the PSIL threshold for differentiation between benign and malignant lesions in patients with chronic liver disease.     

Potential for qualitative diagnosis of tumors and tumorous lesions in the liver with Tc-99m-GSA SPECT —Correlation with pathological evaluation and MRI findings—

To evaluate the effect of technetium-99m-labeled DTPA-galactosyl human serum albumin (Tc-99m-GSA) SPECT imaging for qualitative diagnosis of hepatic lesions. The subjects were 29 patients with pathologically confirmed hepatic lesions (21 malignant and 8 benign lesions). SPECT data were obtained at about 30 minutes after injecting 185 MBq (5 mCi) of Tc-99m-GSA. The GSA SPECT findings were compared with those of pathological evaluation and T2-weighted MR images (T2WI). Of 29 lesions, 17 showed decreased accumulation, and three exhibited increased accumulation. The other nine lesions were undetectable. The malignant lesions which showed increased accumulation were all well differentiated hepatocellular carcinomas (HCCs). One of the eight benign lesions exhibited increased accumulation. The three lesions which showed increased accumulation of GSA exhibited hypointensity on T2WI, whereas the malignant lesions which showed decreased accumulation of GSA exhibited hyperintensity on T2WI. The GSA SPECT findings correlate well with those of T2WI. GSA SPECT may be useful for qualitative diagnosis of focal liver lesions. If a lesion is suspected of being HCC, increased accumulation may indicate well differentiated HCC.     

The value of gadobenate dimeglumine-enhanced delayed phase MR imaging for characterization of hepatocellular nodules in the cirrhotic liver

OBJECTIVES: To evaluate the value of 1-hour delayed phase imaging (DPI) of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging for the characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN) in patients with cirrhosis. MATERIALS AND METHODS: A total of 37 patients with 42 HCCs and 13 DNs were included in this study and all lesions were histopathologically confirmed except for 15 HCCs. T1-weighted 3-dimensional gradient-echo images were acquired before, immediately after (30, 60, 180 s), and 1 hour after bolus injection of gadobenate dimeglumine at a dose of 0.1 mmol/kg. The lesions were classified as isointense, hypointense, or hyperintense compared with the surrounding liver parenchyma on DPI for qualitative assessment. We performed quantitative analyses of the contrast-to-noise ratio (CNR) and of the relative contrast enhancement of the lesion on the DPI. RESULTS: In the qualitative analysis, among 42 HCCs, 30 (71.4%) were hypointense on DPI, and 10 (23.8%) and 2 (4.8%) were isointense and hyperintense, respectively; only 1 of 13 DNs (7.7%) was hypointense and 10 (76.9%) and 2 (15.4%) were isointense and hyperintense, respectively. In contrast, 25 HCCs (71.4%) of 35 hypervascular HCCs were hypointense on DPI, and no hypervascular DN (0/7) was hypointense with statistical significance (P = 0.0007). When we considered the hypointensity of the hepatic lesions on delayed phase as a sign of HCC in cirrhotic liver, our results gave a sensitivity of 71.4% and a specificity of 91.7%. In the quantitative analysis, the mean CNR of the HCCs and the DNs on the 1-hour DPI was -6.32 +/- 6.27 and -0.07 +/- 3.28, respectively; the difference between the HCCs and the DNs was significant (P < 0.05). CONCLUSIONS: Delayed gadobenate dimeglumine-enhanced MR imaging allows improved characterization of HCC in cirrhotic liver. The relative hypointensity to adjacent normal liver parenchyma is a reliable predictor that this lesion favors HCC rather than DN in cirrhotic liver.     

K空间中心部分采集技术肝脏局灶性病变动态增强扫描

目的：探讨Ｋ空间中心部分采集技术肝脏局灶性病变ＭＲ动态增强扫描方法及临床意义。材料与方法：前瞻性研究１１７例肝脏局灶性病变,包括肝细胞性肝癌、肝细胞性肝癌介入治疗后、周围型肝内胆管细胞性肝癌、转移瘤、海绵状血管瘤及肝囊肿。轴位常规自旋回波Ｔ１加权成像及快速自旋回波Ｔ２加权成像后,采用平静呼吸状态下梯度回波Ｋ空间中心部分采集技术、７个连续层面８个时相动态增强扫描。结果：各例均动态增强扫描成功。动态扫描显示时间信号强度曲线在肝细胞性肝癌及肝细胞肝癌介入治疗后活癌组织部分呈速升速降型;胆管细胞癌呈渐升型;转移瘤呈环形强化,缓慢升高型;海绵状血管瘤呈速升平台型;肝囊肿无强化。结论：Ｋ空间中心部分采集技术肝脏局灶性病灶动态扫描,可以在平静呼吸下成像,显示肝脏局灶病变的血供状态特征,有助于术前病灶定性诊断。     

肾上腺疾病的MR影像诊断

本文对５０例正常肾上腺，４２例共４９个肾上腺病灶的ＭＲ影像进行分析，结果表明：（１）正常肾上腺信号均匀，显示率与ＣＴ相似；（２）ＭＲ可清晰显示大于１．０ｃｍ的病灶及其与周围结构的关系；（３）ＭＲ对腺瘤与转移瘤的鉴别有较大的帮助，Ｔ＿２ＷＩ腺瘤类似于肝脏的信号强度，转移瘤与脂肪的信号强度相似；（４）嗜铬细胞瘤的ＭＲ影像有特异性，Ｔ＿２ＷＩ呈明显高信号，４５％见散在点状短Ｔ＿２低信号区。     

3.0T磁共振磁敏感加权成像诊断脑发育性静脉畸形

目的 评价磁敏感加权成像(SWI)在诊断脑发育性静脉畸形(DVA)中的临床应用价值.方法 选取采用3.0T超高场磁共振的SWI及常规MR序列(包括自旋回波T_1加权像、快速自旋回波T_2加权像)诊断为脑发育性静脉畸形的24例患者,对SWI及常规MR序列进行分析.结果 24例脑发育性静脉畸形中发生于额叶白质11例,顶叶白质6例,颞叶2例,小脑半球5例.MR平扫显示DVA病灶11例,其中表现为条状流空信号者4例,表现为T_2WI放射状高信号者7例;MR增强检查显示所有病灶,表现为"海蛇头"样强化特征.SWI检查清晰显示所有病灶,表现为"海蛇头"样低信号影.结论 SWI对小静脉病变较敏感,能取代MR增强检查用于脑发育性静脉畸形的诊断和随访.