Gd-EOB-DTPA增强MRI在肝脏局灶性病变中的应用进展

肝脏局灶性病变是常见的肝脏疾病,常用的影像学检查方法包括超声、CT及MRI,MRI因为具有良好的组织对比及可使用多种对比剂等优势,成为诊断肝脏局灶性病变的重要检查方法.Gd-EOB-DTPA是通过肝细胞特异性摄取的对比剂,Gd-EOB-DTPA增强MRI对于肝脏局灶性病灶的诊断、鉴别诊断、指导治疗等具有重要意义.本文就Gd-EOB-DTPA增强MRI在肝脏局灶性病变中的应用做一综述.     

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.     

脂肪肝背景下肝局灶性病变检出率的比较影像学研究

目的 比较超声(uS)、CT、MRI在脂肪肝背景下肝局灶性病变的检出率.方法 回顾性分析129例同时做过US、CT、MRI的肝局灶性病变患者的影像表现,以临床影像综合诊断为参考标准,将其分为脂肪肝组(41例)和非脂肪肝组(88例),以比较两组分别用US、CT、MRI3种检查方法对肝内局灶性病变数目的检出率.结果 US对脂肪肝组和非脂肪肝组肝局灶性病变的检出率分别为52.50％、70.97％(P=0.003);CT对两组病变的检出率分别为70％、85.71％ (P =0.002);MRI对两组病变的检出率分别为88.75％、87.56％(P=0.780).结论 MRI对肝局灶性病变的检出率最高且不受脂肪肝背景的影响,而US和CT在脂肪肝背景下对肝脏局灶性病变的检出率均受到影响.     

增强CT和MRI轮辐征在诊断肝脏局灶性结节增生中的价值

目的 分析增强CT和MRI轮辐征在鉴别诊断肝脏局灶性结节增生(FNH)和其他肝脏局灶性病变中的价值.方法 回顾性分析经病理证实的210例肝脏局灶性病变患者的增强CT及MRI图像,其中FNH 37例(40个病灶),其他肝脏局灶性病变173例(219个病灶).采用x2检验比较不同检查方式、增强期相FNH轮辐征的检出率,计算...     

肝脏局灶性病变的病理解剖

认识肿瘤样病变及上皮性和间质性肿瘤的病理解剖对肝脏局灶性病变的影象诊断具有重要意义。本文根据病理学知识,对肝脏局灶性病变的病理解剖作系统概述。     

磁共振成像新技术在肝脏局灶性病变诊断中的应用

肝脏病变在临床上是一种常见病。MRI技术被认为是诊断肝脏病变最有价值的影像学方法。尤其近年来,新的MRI技术如扩散加权成像、灌注加权成像、波谱成像、弹性成像等技术的快速发展,使MRI不仅用于观察肝脏病变的形态变化特点,而且可以反映肝脏病变的病理过程及分子学的变化。针对MRI新技术在诊断肝脏局灶性病变中的应用及进展进行综述。     

三维多期动态增强MRI在肝脏局灶性病变中的诊断价值

目的:评价Propeller LAVA序列三维容积多期动态增强MRI检查对肝脏局灶性病变的诊断价值.方法:回顾性分析83例行Propeller LAVA序列三维容积多期动态增强MRI检查的肝脏局灶性病变的血供特点、强化表现,从而推断其组织学特点,并与最终病理诊断或临床诊断相比较.结果:有1例患者图像质量不能满足诊断要求而未能纳入本研究.余82例患者共检出富血供病变65例,包括肝细胞癌31例,肝血管瘤29例,局灶结节增生4例,肾癌肝转移瘤1例.低血供病变17例,其中结节型肝细胞癌2例,肝转移瘤10例,肝内胆管细胞癌3例,炎性假瘤2例.富血供病变在肝动脉期明显强化,除4例局灶结节增生在门静脉期和延迟期与邻近肝实质信号强度近似外,余61例富血供结节在门静脉期和延迟期均表现为明显的低信号强度;低血供病变在肝动脉期强化不显著,除1例炎性假瘤在延迟期与邻近肝实质信号相等外,余16例低血供病变在门静脉期和延迟期均低于邻近肝实质信号强度.结论:Propeller LAVA序列动态增强MRI检查能够准确显示肝脏局灶性病变的血供特点,清晰显示病变的形态、边缘及强化表现,从而准确判定其组织学性质.     

肝局灶性病变CT与MRI动态增强对照研究

目的:探讨肝局灶性病变在CT和MRI动态增强中的影像差异及其原因,以提高对CT及MRI各自动态增强表现的认识。方法:搜集17例肝脏局灶性病变患者的临床资料,其中7例肝细胞肝癌,5例海绵状血管瘤,2例腺瘤,2例局灶结节性增生,1例转移瘤。全部病例均分别行CT及MRI的平扫和三期动态增强扫描;MRI采用SE序列加快速扰相梯度回波序列,将CT和MR动态增强图像进行对照观察,包括动态增强各期的强化范围、强化方式和强化幅度,强化幅度的比较用病灶密度(信号)与肝脏密度(信号)的比值进行比较。结果:肝癌、腺瘤和局灶结节性增生在CT与MRI上强化范围相似。1例肝癌动脉期强化幅度MRI大于CT,3例肝癌和2例局灶结节性增生门脉期及延迟期强化幅度MRI大于CT,2例腺瘤增强各期强化幅度MRI均大于CT,以动脉期差异最大。5例海绵状血管瘤强化范围动脉期及门脉期MRI大于CT,延迟期则相仿。1例转移瘤CT增强各期均未见明显强化,MRI门脉期及延迟期可见环状强化。结论:肝局灶性病变CT与MRI动态增强表现存在一定的差异,主要表现为部分病变增强各期强化幅度MRI大于CT,尤以动脉期差异最大;部分病变增强范围MRI大于CT。     

肝内局灶性病变菲立磁增强MRI-组织病理相关性研究

目的分析肝内局灶性病变菲立磁增强信号强度变化与Kupffer细胞计数的关系。方法搜集行菲立磁增强MR扫描并经手术病理证实的12例16个肝细胞癌(HCC)病灶以及良性病变9例16个病灶,分别计算局灶性病变相对于肝组织的Kupffer细胞的比率以及菲立磁增强前后T1WI、T2WI信号的相对比率,并进行相关性分析。结果良、恶性肝内局灶性病变间Kupffer细胞比率差异有统计学意义,随着HCC分化程度的降低,病灶内Kupffer细胞计数比率呈下降趋势(P<005)。T2WI强化比率与Kupffer细胞计数比率呈负相关(r=-0780,P<005);T1WI强化比率与Kupffer细胞计数比率呈正相关(r=0389,P<005)。结论肝内局灶性病变间Kupffer细胞计数比率的明显差异是菲立磁增强MRI鉴别肝内良、恶性病灶的基础,T2WI序列能有效地鉴别肝内良、恶性疾病,是鉴别肝内良恶性局灶性病变的MR检查首选序列。     

超声造影与增强CT对肝脏良恶性病变的诊断价值研究

目的：比较超声造影和增强CT对肝脏良恶性病变的诊断价值。方法：对同时接受肝脏超声造影和增强CT检查的肝内局灶性病变48例进行分析,重点对肝内局灶性病变良恶性判断的敏感度、特异性、预期准确度及病理符合率进行比较。结果：超声造影对肝脏局灶性病变良恶性判断的敏感度为96．7％,特异性为94．1％,预期准确度96．8％,病理类型符合率为84．7％;增强CT则分别为90．7％、92．8％、0.96．7％和86．9%。结论：超声造影对肝脏局灶性病变有较高诊断价值,与增强CT相结合可进一步提高病理诊断符合率。     

Focal liver lesions: MR imaging-pathologic correlation

Magnetic resonance signal intensity of focal liver lesions is affected by numerous pathologic factors. Lesion histologic features, such as cellularity, vascularity, stromal component, and intratumoral necrosis or hemorrhage, strongly affect T1 and T2 relaxation times. Additionally, intracellular content of certain substances, such as glycogen, fat, melanin, iron, and copper, may also have a substantial role in determining MR signal behavior. In this review we discuss the correlations between MR imaging features and pathologic findings in benign and malignant focal liver lesions. Knowledge of imaging-pathology correlations greatly assist in charac terizing focal lesions. Moreover, in certain tumor histotypes, such as hepatocellular carcinoma, careful analysis of lesion signal intensity may help predict the degree of tumor differentiation.     

Clinical value of MRI liver-specific contrast agents: a tailored examination for a confident non-invasive diagnosis of focal liver lesions

Screening of the liver for hepatic lesion detection and characterization is usually performed with either ultrasound or CT. However, both techniques are suboptimal for liver lesion characterization and magnetic resonance (MR) imaging has emerged as the preferred radiological investigation. In addition to unenhanced MR imaging techniques, contrast-enhanced MR imaging can demonstrate tissue-specific physiological information, thereby facilitating liver lesion characterization. Currently, the classes of contrast agents available for MR imaging of the liver include non-tissue-specific extracellular gadolinium chelates and tissue-specific hepatobiliary or reticuloendothelial agents. In this review, we describe the MR features of the more common focal hepatic lesions, as well as appropriate imaging protocols. A special emphasis is placed on the clinical use of non-specific and liver-specific contrast agents for differentiation of focal liver lesions. This may aid in the accurate diagnostic workup of patients in order to avoid invasive procedures, such as biopsy, for lesion characterization. A diagnostic strategy that considers the clinical situation is also presented.     

MR imaging of focal splenic tumors

This study was undertaken to define the MR appearance of splenic tumors in 16 cancer patients with focal splenic lesions; 50 volunteers and liver cancer patients without splenic abnormalities served as controls. In 14 patients with focal splenic lesions, differences between splenic and lesion signal intensities permitted detection of splenic lesions on MR images, either because of cystic or necrotic areas lengthening T2 within the tumor, because of T1 shortening from tumor-associated hemorrhage, or because of T2 shortening of surrounding spleen in two cases of suspected transfusional iron overload. In one spleen, a lesion appeared isointense on both T1- and T2-weighted pulse sequences and was detected only by gross splenic deformity. In one other case, CT defined splenic metastases not visible on MR images. Measurements of signal intensity of normal spleens and tumor are so similar that spin-echo MR imaging can underestimate the size and extent of focal splenic disease or may miss lesions entirely. We conclude that MR imaging is a less sensitive technique for detecting focal lesions of the spleen than for detecting focal hepatic lesions.     

Mr imaging of hepatic nodular regenerative hyperplasia

Nodular regenerative hyperplasia (NRH), a rare condition that is commonly associated with noncirrhotic portal hypertension, is not well described in the MR literature. Three patients at two institutions were identified who had both abdominal MR imaging and pathologic evidence of NRH. All examinations were performed at 1.5 T and included axial T1- and T2-weighted spin-echo (SE) images. The MR studies were reviewed by two radiologists in consensus. Two patients had multiple liver lesions that had high signal components on T1-weighted images and were predominantly isointense with liver on the T2-weighted images. One patient had no focal lesions identified. NRH, when visualized on MR images, appears as multifocal masses with shortened Tl and T2 similar to liver. NRH should be considered in the differential diagnosis of hepatocellular tumors, especially in patients with a predisposing condition.     

肝脏多发局灶性结节性增生的MRI诊断

目的 评估MR诊断肝脏多发局灶性结节性增生(focal nodular hyperplasia,FNH)的价值.方法 回顾性分析经病理证实的9例多发FNH的MR表现,并与部分病灶病理所见对照.结果 9例诊断均考虑到FNH的可能性,5例第一诊断考虑为FNH,3例第一诊断考虑为肝腺瘤,1例第一诊断考虑为纤维板层型肝癌.9例共31个病灶,T2WI 19个呈稍高信号、12个呈等信号;T1WI上12个呈稍低信号、7个呈等信号、12个呈高信号;反相位成像1个病灶局部信号略有减低.注射Gd-DTPA后,动脉期18个病灶轻度至明显不均匀强化、11个病灶显著均匀强化、1个病灶中度不均匀环形强化、1个病灶未见异常强化;门静脉期和延迟期31个病灶均逐渐呈等信号或稍高信号.共16个病灶出现中央瘢痕,瘢痕延迟期强化.结论 多发FNH有特征性表现,大部分病例MR能正确诊断.     

Focal nodular hyperplasia of the liver: MR findings in 35 proved cases

MR images of 28 patients with 35 lesions of hepatic focal nodular hyperplasia were reviewed to determine the frequency of findings considered typical of this condition (isointensity on T1- and T2-weighted pulse sequences, a central hyperintense scar on T2-weighted images, and homogeneous signal intensity). Fifteen lesions were imaged at 0.6 T with T1- and T2-weighted spin-echo (SE) pulse sequences; 20 lesions were imaged at 1.5 T with T1-weighted SE and gradient-echo pulse sequences and T2-weighted SE pulse sequences. Diagnosis of focal nodular hyperplasia was made pathologically in 25 patients, with nuclear scintigraphy in four, and with follow-up imaging in six. Only seven lesions (20%) were isointense relative to normal liver on both T1- and T2-weighted images. On T1-weighted SE images, 21 lesions (60%) were isointense relative to normal liver, 12 (34%) were hypointense, and two (6%) were hyperintense. On T2-weighted SE images, 12 lesions (34%) were isointense and 23 (66%) were hyperintense relative to normal liver. A central scar was present in 17 lesions (49%) and was hypointense relative to the lesion on T1-weighted images and hyperintense on T2-weighted images. Twenty lesions (57%) were of homogeneous signal intensity throughout the lesion, except for the presence of a central scar. All three MR imaging characteristics were present in three cases (9%). We conclude that hepatic focal nodular hyperplasia has a wide range of signal intensity on MR imaging.     

The influence of MR field strength on the detection of focal liver lesions with superparamagnetic iron oxide

The purpose of this study was to compare the value of low- vs high-field MR systems in the detection of focal liver lesions after IV administration of iron oxide particles. A prospective study was undertaken which included 20 patients with focal liver lesions on CT or US, or strong clinical suspicion of focal liver disease. Iron oxide particles were administered in an IV drip infusion over 30 min. Magnetic resonance imaging was subsequently performed on a 0.2 and a 1.5-T system. Both examinations were performed in one session. Turbo spin-echo T2-weighted sequences were used for further analysis (at 0.2 T: TR 4050 ms, TE 96 ms; 1.5 T: TR 3000 ms, TE 103 ms). After randomisation, images were analysed by two blinded readers. The evaluation included lesion counts, determination of lesion conspicuity and overall image quality (both graded on a scale 1–5). Quantitative analysis was performed on 29 lesions. Lesion-to-liver signal intensity and contrast-to-noise ratios (CNRs) were calculated. The total lesion count (cumulative counts for two observers) was 59 on the high-field system and 63 on the low-field system. Statistical analysis showed no significant difference. On both systems median value for lesion conspicuity was 3. No statistically significant difference was found. Global image quality was rated higher on the high-field system: 3 vs 2 for the low-field system (p = 0.0017). Quantitative analysis showed no significant difference for lesion-to-liver signal intensity ratios or CNRs. Although subjective image quality is significantly better on the high-field system, this does not result in better lesion detection or better lesion conspicuity. No significant difference in objective quantitative parameters was found in our series. Received 25 June 1996; Revision received 28 October 1996; Accepted 25 November 1996     

Dysembryoplastic neuroepithelial tumors: MR appearance.

PURPOSE: Dysembryoplastic neuroepithelial tumor (DNT) is a newly described, pathologically benign tumor arising within the supratentorial cortex and having a 100% association with partial complex seizures. We reviewed the MR appearance of the brains of six patients with DNT, without and with administration of gadolinium-DTPA, emphasizing the clinical and radiologic features. METHODS: The MR images in six patients (five male, one female) with pathologically proved DNT were reviewed. Five had partial complex seizures and one had partial simple seizures. Age at onset of partial seizures ranged from 2 to 19 years. Scans were obtained with conventional T1 and T2 weighting without and with the administration of gadolinium-DTPA. All patients had craniotomies for medically refractory seizures and pathologic examination of all specimens was available for review. RESULTS: MR demonstrated a focal cortical mass in all patients. Five were located in the temporal lobe and one was located within the occipital lobe. Two showed enhancement with gadolinium-DTPA. Calcification occurred in one lesion. Common features included very low signal intensity on T1-weighted images and high signal on T2-weighted images, similar to cerebrospinal fluid. Proton density images demonstrated slightly higher signal intensity in the lesion than cerebrospinal fluid. The margin of the tumor is well-circumscribed and may remodel the adjacent calvarium. CONCLUSIONS: DNT, a newly described pathologic entity resulting in chronic, often medically, intractable seizures, has characteristic features on MR that allow it to be suggested in the differential diagnosis. These lesions may simulate benign cysts; however, increased signal intensity on proton density images should prompt further investigation in the proper clinical setting. Differentiation from low-grade astrocytomas and ganglioglioma is not possible by MR.     

Malignant hepatic tumors: Changes on MRI after hepatic arterial chemoembolization – preliminary findings

This study describes the MR appearances of malignant hypervascular liver lesions pre- and post-hepatic-arterial chemoembolization, with correlation to serial imaging and clinical responses. Eight patients with malignant hypervascular liver lesions underwent pretreatment and posttreatment MR examination on a 1.5-T MR imager. MR sequences included T1-weighted spoiled gradient echo (SGE), T2-weighted fat-suppressed spin echo or turbo spin echo, and dynamic gadolinium-enhanced SGE images. All patients underwent pretreatment, initial posttreatment, and subsequent posttreatment MR studies. The histology of primary tumors included various types of hepatocellular carcinoma (HCC) (four patients: fibrolamellar HCC [one patient], HCC [two patients], mixed HCC/cholangiocarcinoma [one patient]) and liver metastases (four patients: untyped islet cell tumor [two patients], gastrinoma [one patient], carcinoid [one patient]). Response to chemoembolization was determined by three assessments: MR response, serial imaging response, and clinical response. The appearance of MR response to chemoembolization was determined based on the correlation with clinical and serial imaging response. The MR response of lesions that showed good clinical response included: increase in signal intensity on T1-weighted images (three patients), decrease in signal intensity on T2-weighted images (three patients), and negligible or minimal enhancement on immediate postgadolinium images (four patients) after chemoembolization. The most marked change in lesion appearance was observed in lesions < 1 cm, which had intense homogeneous enhancement on pretreatment MR studies and negligible enhancement on initial posttreatment MR examinations. MR response of lesions that showed moderate clinical response demonstrated a variety of lesion appearances from substantial change to minimal change. MR response of lesions that showed poor clinical response demonstrated no change in lesion appearances compared with the pretreatment MR study. Our results demonstrated change in appearance of liver lesions between pre- and post-hepatic-arterial chemoembolization MR studies. MR response correlated with response determined by serial imaging studies and clinical findings.     

Initial clinical experience with oral manganese (CMC-001) for liver MR imaging

Recently, a new oral liver-specific manganese-based MR agent (CMC-001) has been introduced. This contrast medium is delivered to the liver in high concentrations in the portal vein and very low doses in the hepatic artery, as only small amounts of manganese enter the general circulation. It is taken up by the hepatocytes and excreted in the bile. Our initial experience with the new MR contrast medium in a variety of patients is reported. A total of 20 patients (11 males and 9 females) were studied with MR imaging 2 h after oral ingestion of the contrast agent. Sixteen patients were referred for evaluation of focal liver lesion(s), whereas in the remaining four patients, evaluation of the biliary tract was requested. In the 17 patients without biliary obstruction, there was an increased signal intensity of the liver parenchyma, whereas in the three patients with biliary obstruction, the uptake was delayed. There was excellent visualization of the biliary system on the T1-weighted images in the 16 patients without biliary obstruction referred for evaluation of a focal liver lesion. In seven patients, the uptake was patchy. In patients with focal liver lesions or biliary tract diseases, it is possible to increase the signal intensity of the liver parenchyma after the oral intake of CMC-001. In patients without biliary tract obstruction, the biliary system is easily visualized. Oral manganese seems to be useful in hepatobiliary MRI. Further research is strongly warranted. Financial disclosure: Thomsen HS. Manganese-containing magnetic resonance contrast agent. US patent no. 6,015,545/ 18 January 2000.