MR imaging of hepatocellular carcinoma at 1.5 Tesla

The authors investigated the magnetic resonance appearance of hepatocellular carcinoma using a 1.5-Tesla magnet. Twenty-four patients with pathologically proven hepatocellular carcinoma had magnetic resonance imaging (MRI) studies, which were retrospectively reviewed. All patients were imaged with at least two of the following techniques: (1) T1-weighted (T1W), (2) T1-weighted with Gd-DTPA enhancement (T1W-E), (3) T2-weighted (T2W), (4) proton density (PD), and (5) gradient-recalled echoes (GRE). T1W images were equal to T2W images for tumor detection using a grading system. T1W images were slightly better than T2W images for the total number of lesions detected. The other pulsing techniques (PD, T1W-E, and GRE) detected fewer lesions. Eight cases of hepatocellular carcinoma (33%) had nonhomogeneous increased signal intensity on both T1W and T2W images. The authors conclude that T1W images are equal to T2W images for detection of hepatocellular carcinoma. The authors also conclude that 33% of hepatocellular carcinomas have an imaging pattern with increased signal intensity on both T1W and T2W images. This pattern is atypical for most other hepatic masses and hence can be used to suggest the mass is hepatocellular carcinoma.     

Noninvasive imaging of unusual regenerating nodules in the cirrhotic liver

Despite the common occurrence of regenerating liver nodules, little has been written regarding their ultrasound or computed tomographic appearance. In the great majority of cases, they have an echo texture and CT number identical to surrounding hepatic parenchyma. Exceptionally, as in the 2 cases described, they can mimic a malignant neoplasm. Because radionuclide imaging almost always demonstrates uptake over a regenerating nodule, this modality should be used in suspicious cases in conjunction with either ultrasound or computed tomography in order to exclude a malignancy.     

肝硬化不典型增生结节的多模态MRI研究

目的采用多模态MR成像对肝硬化背景下不典型增生结节（DN）的影像学特征进行研究,揭示DN的影像学特征与病理演变机制的相关性。材料与方法经手术、病理、实验室检查、随访追踪及多种影像综合检查确诊的15例DN患者。所有患者均行多模态MRI检查。结果 DN病灶在MRI平扫T1WI呈高信号者为80%,T2WI呈等、低信号者为66.7%。T1WI、T2WI的SNR、CNR值显示DN信号相对于肝实质变化不明显。DWI呈等、低信号者为80%;SWI对DN病灶的检出率为100%。癌变的DN灶在T1WI上主体呈现略高信号,其内可见相对略低信号的区域;T2WI主体呈略高、等或略低信号,中心可见相对高信号小结节。癌变灶DWI均为高信号。动态增强扫描DN病灶的时间-信号强度曲线与周围肝实质基本相同,而DN的癌变区域有明显类似肝癌强化样的曲线。与病理结果相对照,部分HGDN可通过影像特征进行诊断。结论揭示部分DN的影像学特征与病理基础间的相关性,进一步阐释了DN多模态影像学的本质特征。     

Dynamic contrast-enhanced MR imaging of fibrolamellar hepatocellular carcinoma

The magnetic resonance (MR) appearance of fibrolamellar hepatocellular carcinoma (FL-HCC) on T1- and T2-weighted and dynamic serial postgadolinium-DTPA images is reported. Both tumors were large (>7 cm in shortest dimension) and had central regions of low signal intensity on T1- and T2-weighted images. Diffuse heterogeneous enhancement of the tumors occurred on immediate postcontrast images. Lesions became more homogeneous in enhancement over time, but lack of enhancement of central portions of the tumor persisted. Although persistent lack of enhancement of the tumor scar on late postcontrast MR images may be characteristic of FL-HCC compared with delayed enhancement in focal nodular hyperplasia, the potential similarities between these tumors is stressed.     

MRI纹理分析鉴别诊断肝硬化背景下小肝癌与增生结节

目的 探讨常规MRI纹理分析鉴别诊断肝硬化背景下小肝癌与增生结节的价值。方法 回顾分析经病理证实的33例小肝癌和19例肝增生结节患者的MRI资料。采用MaZda软件手工勾画ROI,提取T1WI、T2WI、频率选择性预脉冲脂肪抑制T2WI及T1WI增强扫描图像中病变的纹理特征。通过Fisher系数、分类错误概率联合平均相关系数（POE+ACC）、交互信息（MI）及三者联合（FPM）的方法选择最佳纹理参数集合。使用原始数据分析（RDA）、主要成分分析（PCA）、线性判别分析（LDA）和非线性判别分析（NDA）进行纹理分类。同时由2名MRI诊断医师共同评估所有影像学资料。比较纹理分析与医师鉴别诊断两种病变结果的差异。结果 52例中,共60个病灶。鉴别小肝癌与增生结节的纹理特征主要来自T2WI,误判率最小为8.33%（5/60）。纹理特征选择方法中,FPM的误判率（8.33%~26.67%）均低于MI （20.00%~38.33%）、Fisher （18.33%~41.67%）和POE+ACC （8.33%~40.00%）。纹理特征分类方法中,NDA判别两种病变的误判率（8.33%~20.00%）均低于RDA （26.67%~41.67%）、PCA （28.33%~43.33%）和LDA （21.67%~45.00%）。影像医师的误判率为23.33%（14/60）,高于采用纹理分析鉴别两种病变的误判率（5/60,8.33%;χ²=58.73,P=0.002）。结论 常规MRI纹理分析可用于鉴别肝硬化背景下小肝癌与增生结节。     

Management of adenomatous hyperplastic nodules in the cirrhotic liver: US follow-up or percutaneous alcohol ablation?

In order to investigate the most appropriate management of adenomatous hyperplastic nodules in cirrhosis (AHNs), retrospective and prospective studies were undertaken. The retrospective study included 11 AHNs detected in nine patients, who were followed with ultrasonography (US) and fine-needle biopsy (FNB); seven of these lesions evolved into hepatocellular carcinoma (HCC) after a mean follow-up period of 11.4 months. The prospective study involved 19 AHNs (in 12 patients) that were submitted to percutaneous ethanol injection (PEI); all lesions underwent necrosis at the dynamic computed tomographic (CT) examination and at multiple FNBs performed 1 month after the end of treatment. In four patients studied with magnetic resonance (MR), all treated lesions were markedly hypointense in the T2-weighted images. No complications occurred after a total number of 114 alcohol injections. No local recurrences were observed after a mean follow-up period of 16.9 months. PEI should therefore be considered mandatory in the management of AHNs.     

MR findings of hepatic cavernous hemangioma after intraarterial infusion of iodized oil

Magnetic resonance (MR) imaging was performed on five tumors of three patients who had hepatic hemangiomas. Four tumors were given an intraarterial infusion of 3–8 ml of iodized oil, while one tumor was not. MR images were obtained at 2.0 or 0.5 T. A single spin echo sequence with TE of 30 ms and TR of 500 ms and a double echo sequence with TEs of 60 and 150 ms and TR of 2000 ms, were used to produce relatively T1-, T2-weighted, and heavily T2-weighted images, respectively. Follow-up MR imaging was done 1–5 months after infusion of iodized oil. On relatively T1 weighted images, hemangiomas showed iso or hypointensity. On T2-weighted images, all tumors showed hyperintensity. However, on heavily T2-weighted images, tumors with iodized oil showed heterogeneous, slight hyperintensity, while tumors without iodized oil showed characteristic appearance of marked hyperintensity in hemangiomas. In hepatic cavernous hemangiomas with intraarterial infusion of iodized oil, familiarity with this unusual MR intensity of tumors on heavily T2-weighted images is useful to avoid the incorrect diagnosis and to reduce the frequency of inappropriate hepatic resection.     

3.0T磁共振R2~*值在肝纤维化诊断及分期中应用价值初探

目的:探讨磁共振R2*值在肝纤维化诊断与分期中的应用价值。方法:分别对8例健康志愿者和36例肝脏穿刺病理证实的肝纤维化患者、4例临床明确诊断肝硬化患者进行3.0T磁共振血氧水平依赖成像(BOLD-MRI),重建R2*map并测算肝脏平均R2*值,采用非参数Spearman检验分析R2*平均值与病理肝纤维化分期的相关性、采用Dunnett T3检验及Mann-Whitney U检验分析不同纤维化分期的组间差异,采用ROC曲线评价R2*平均值预测肝纤维化的效能。结果:正常志愿者组、肝纤维化组的R2*平均值分别为(47.63±5.98)Hz、(60.11±12.18)Hz。随着纤维化分期的进展,R2*平均值逐渐增大,R2*平均值与肝纤维化分期呈正相关(r=0.698,P<0.01)。不同纤维化分期的肝脏R2*平均值的差异有统计学意义(F=17.05,P<0.001),R2*平均值在S0与S1、S2、S3、S4,S1与S2,S2与S3之间的差异均有统计学意义(P≤0.05)。R2*平均值预测肝纤维化≥S1期的能力优于预测肝纤维化≥S2期、≥S3期、≥S4期,曲线下面积0.927,敏感度0.966,特异度0.737(R2*≥49.32 Hz)。结论:肝脏BOLD-MRI的R2*值可反映肝纤维化严重程度,是区分肝纤维化及其分期较为敏感的方法,有用于临床肝纤维化评价的潜能。     

原发性胆汁性肝硬化的MRI表现

目的 总结原发性胆汁性肝硬化(PBC)的MRI征象,探讨MRI对PBC的诊断价值及其对肝纤维化程度的评估价值。方法 回顾性分析临床确诊为PBC的45例患者(其中33例接受肝穿刺活检)的MRI征象,并与病理结果进行相关性分析。结果 45例PBC的MRI征象:弥漫性肝大17例(17/45,37.78%);门静脉周围T2WI高信号影35例(35/45,77.78%);T2WI肝脏信号不均匀34例(34/45,75.56%);门静脉周围晕征34例(34/45,75.56%);腹部淋巴结增大39例(39/45,86.67%)。接受肝穿刺活检的33例PBC中,肝脏信号不均匀性分级与组织学分期存在明显正相关(r=0.703,P<0.001);晕征在组织学各期出现频率差异有统计学意义(P=0.034),晕征分级与组织学分期呈正相关(r=0.687,P<0.001),其中Ⅰ期与Ⅱ期比较,晕征分级无统计学意义(P=0.841),Ⅱ期与Ⅲ期、Ⅲ期和Ⅳ期比较差异有统计学意义(P均<0.05);增大淋巴结在组织学各期出现频率、大小差异均无统计学意义(P均>0.05)。结论 MRI诊断PBC有重要价值,晕征及肝脏信号不均匀性有助于肝纤维化程度的评估。     

DTI评估大鼠肝纤维化及早期肝硬化的实验研究

目的：通过大鼠模型比较并评估常规DWI和DTI肝纤维化及早期肝硬化的临床鉴别诊断的价值。材料与方法采用经典四氯化碳方法建立SD大鼠肝纤维化模型7只、早期肝硬化模型5只,正常对照组6只（该实验经实验动物伦理委员会批准）。采用1.5 T超导型MRI系统及腕关节线圈肝脏MR扫描,包括DWI、DTI序列。扫描参数：DWI b值为0,500 s/mm2;DTI b值为500 s/mm2,在6个正交方向施加扩散梯度。层厚3 mm,矩阵192×128,激励次数（NEX）为4。在ADW 4.4工作站上分别对DWI及DTI进行后处理,重建出ADC图及FA图（DTI）。分别测量肝脏右叶的ADC值及FA值。应用秩和检验分析DWI的ADC值及DTI的ADC值、FA值与正常、肝纤维化、早期肝硬化分级的相关性,并进行两两比较。结果 DWI的ADC值在正常组（0.001545±0.00013）、肝纤维化组（0.001116±0.00014）、早期肝硬化组（0.000791±0.00018）中呈递减趋势,正常组与肝纤维化组、早期肝硬化组差异有统计学意义（P〈0.05）,而肝纤维化组与早期肝硬化组差异无统计学意义。DTI序列中,正常组ADC值（0.017175±0.00097）±10-7高于肝纤维化组（0.011510±0.00080）±10-7和早期肝硬化组（0.010556±0.00195）±10-7,差异有统计学意义,但纤维化组与早期肝硬化组之间的差异无统计学意义;FA值在正常组（0.2278±0.0123）、肝纤维化组（0.3088±0.1509）与早期肝硬化组（0.4216±0.0388）中呈递增趋势,各组之间差异均有统计学意义（P〈0.05）。结论肝脏DWI与DTI的ADC值均可用于对肝脏纤维化性病变的评估,但对区分肝纤维化与早期肝硬化的价值有限。D T I的FA值不但能区分正常与肝脏纤维化性病变,而且能较好地反映肝纤维化与早期肝硬化之间的差异。     

Capsule and mosaic pattern of hepatocellular carcinoma: Correlation between CT and MR imaging

Computed tomography (CT) was compared with magnetic resonance (MR) imaging in depicting the capsule and the mosaic pattern of hepatocellular carcinoma in 34 patients. The kappa statistic was used to compare results from both modalities. For the detection of the capsule, there was a substantial agreement beyond chance between late enhanced CT (more than 5 min after dynamic CT) and MR imaging (kappa=0.76). Late enhanced CT and MR imaging had almost perfect agreement for the demonstration of the mosaic pattern (kappa=0.85). These agreements were better than the agreements between unenhanced CT and MR imaging or between early enhanced CT and MR imaging. These results suggest that late enhanced CT compares favorably with MR imaging in depicting the capsule and the mosaic pattern of hepatocellular carcinoma.     

MRI manifestations of gastrointestinal lymphoma

The magnetic resonance (MR) images of 11 cases of gastrointestinal lymphoma are presented. The findings include irregularly thickened mucosal folds, irregular submucosal infiltration, annular constricting lesion, exophytic tumor growth, mesenteric masses, and mesenteric/retroperitoneal lymphadenopathy. The tumors were homogeneous and intermediate in signal intensity on T1-weighted images. Heterogeneously increased signal intensities were noted on T2-weighted images. There was mild to moderate enhancement after intravenous administration of gadolinium dimeglumine (Gd-DTPA). The submucosal tumor infiltration might be outlined between the strongly GD-DTPA-enhanced mucosa and the low-intensity muscular layer. In one case that received tumor resection, the pathological examination showed destruction of most parts of the muscular layer, and the MR images did not disclose the low intensity muscular zone.     

Accumulation of iron oxide particles around liver metastases during MR imaging

The histologic nature of the bright ring (peritumoral edema) around some liver metastases on T2-weighted magnetic resonance (MR) images is controversial. In the case reported, particles of the iron oxide contrast agent AMI-25 are retained in the peritumoral zone of a colon cancer metastasis, causing the bright ring to disappear. The location of iron particles in resected specimens could be used systematically to study peritumoral edema.     

增强MRI评估慢性乙型肝炎及乙型肝炎后肝硬化肝脏血管直径的变化

目的利用增强MRI评估慢性乙型肝炎(CHB)及乙型肝炎(乙肝)后肝硬化时肝内外血管直径的变化。方法回顾性分析49例CHB、乙肝后肝硬化患者及18例正常对照者动态增强MRI显示的肝内外血管的直径,分析其与肝纤维化程度的关系。结果肝右静脉(rs=-0.492)、肝中静脉(rs=-0.545)和肝左静脉(rs=-0.423)直径与肝纤维化程度呈负相关(P<0.05),门脉右支(rs=0.573)、门脉主干(rs=0.598)、脾静脉(rs=0.478)和肠系膜上静脉(rs=0.510)直径与肝纤维化程度呈正相关(P<0.05);而腹腔干、脾动脉、肝总动脉、肠系膜上动脉及门脉左支直径与肝纤维化程度无相关(P均>0.05)。结论随着肝纤维化程度加重,肝静脉逐渐变窄,门脉系统逐渐增宽,肝周动脉变化不明显。     

MRI findings of primary biliary cirrhosis: correlation with Scheuer histologic staging

Magnetic resonance imaging (MRI) findings of primary biliary cirrhosis (PBC; currently regarded as a vanishing bile duct syndrome) are not established. In this report, we describe our preliminary analysis of the relation between MRI findings and histopathologic staging of PBC and review clinical, morphologic, and MRI findings of PBC especially focusing on the staging of PBC.     

动态MRI和MSCT在肝硬化伴肝癌诊断中的比较研究

目的对比动态MRI和MSCT对肝硬化伴肝癌的敏感性，并用肝移植术后病理切片作对照。方法73例肝硬化患者肝移植前90天内行MR和MSCT检查，所有患者检查前均不知其有无肝癌。MR扫描FLASH／T1WI、TSE／T2WI序列、动态3期增强扫描被获得。MSCT快流率注射对比剂优维显后行3期扫描；MR结果与MSCT相对照。结果病理检查发现12例患者共20个肝癌，MRI发现其中12／20个肝癌，敏感性为60％，其中发现85．7％（6／7）的〉2cm的病变、46．2％（6／13）个≤2cm的病变。MSCT发现11／20个肝癌，敏感性为55％，其中发现100（7／7）的〉2cm的病变、30．8％（4／13）个≤2cm的病变。对于肝癌的检出敏感性MRI与MSCT无差别。结论MRI和MSCT对肝硬化伴肝癌的敏感性无显著差异，均可用于肝硬化病人移植前发现肝癌，但对小肝癌（≤2cm）的敏感性仍需提高。     

肝硬化扩散加权成像与病理对照研究

目的研究肝硬化扩散加权成像ADC值的变化、机制及其病理基础。方法对11例经病理证实的肝硬化病人和12例正常肝脏行扩散加权成像并测量ADC值,DWI序列所选用b值分别为0、50、1000s/mm2。在b=50s/mm2及b=1000s/mm2计算得到ADC1及ADC2;测量结果与病理表现对照。结果肝硬化平均ADC1、ADC2均显著低于正常肝脏。病理表现为广泛纤维组织增生、小叶结构紊乱和假小叶形成。结论肝硬化组织ADC值降低原因可能为:①肝内纤维组织限制了水分子的活动,②肝实质内血流灌注减少。     

MR弥散加权成像诊断肝硬化不典型癌变结节

目的 探讨MR弥散加权成像(DWI)对肝硬化不典型癌变结节的诊断价值.方法 对34例经临床及病理确诊的肝硬化不典型癌变结节患者行常规MR平扫、动态增强扫描及DWI(b值分别取0、500、1000 s/mm~2),比较常规扫描及DWI对肝硬化癌变结节的检出率.结果 常规扫描及动态增强扫描共发现21例肝癌28个癌结节,弥散加权成像发现27例共37个癌结节,弥散加权成像发现的病例数及结节数均多于常规MR平扫及增强扫描,两种检查方法对癌变结节检出率的比较差异有统计学意义(P=0.025).结论 DWI诊断肝硬化不典型癌变结节较MR常规及动态增强扫描更为敏感.     

HBV相关肝硬化结节多步演变MR影像特征研究现状及最新进展

肝硬化结节经历了从再生结节（RN）、低级不典型增生结节、高级不典型增生结节,最后进展为肝细胞癌的多步骤癌变过程,早期鉴别肝硬化各阶段结节性质对诊断及预后具有重要意义。相对于常规CT检查,MRI作为一种无创性检查方法,在对整个肝脏进行评估方面取得了一定的突破,特别是DWI、SWI等新技术的应用,更有利于RN的诊断。作者就肝硬化结节多步演变过程进行综述。     

超声造影鉴别诊断肝硬化背景下的小肝癌与不典型增生结节

目的观察肝硬化背景下小肝细胞癌(SHCC)与不典型增生结节(DN)的CEUS灌注增强特点,探讨CEUS的鉴别诊断价值。方法对肝硬化背景下42个SHCC病灶和21个DN病灶进行术前CEUS检查,观察病灶CEUS各时相的增强水平,比较其增强模式。结果 SHCC与DN各时相的增强水平及整体增强模式差异均有统计学意义(P均<0.05)。动脉相SHCC以高增强为主,DN以低增强为主;SHCC的增强模式主要为动脉相高增强、门脉相及延迟相呈低增强,DN的增强模式复杂多样。结论肝硬化背景下SHCC与DN有不同的CEUS灌注增强特点,CEUS有助于鉴别诊断。