MnDPDP增强MRI在肝内占位病变的临床应用

MnDPDP是一种新型阳性肝细胞特异性MR对比剂,主要由肝细胞摄取,可缩短T1,使肝脏信号升高,有"照亮肝脏"之说,而病变区非正常肝细胞不能摄取MnDPDP而信号保持不变,两者对比度增加而显示病变.介绍有关MnDPDP对肝脏增强机理、扫描方法、肝内占位病变影像学表现、效果及安全性评估.     

MnDPDP增强MRI在肝内占位病变的临床应用

MnDPDP是一种新型阳性肝细胞特异性MR对比剂，主要由肝细胞摄取，可缩短T1，使肝脏信号升高，有“照亮肝脏”之说，而病变区非正常肝细胞不能摄取MnDPDP而信号保持不变，两者对比度增加而显示病变。介绍有关MnDPDP对肝脏增强机理、扫描方法、肝内占位病变影像学表现、效果及安全性评估。     

MRI与CT 检测肝脏占位病变临床价值分析

目的：比较MRI和增强CT扫描在肝脏占位病变诊断中的应用价值。方法采用MRI和增强CT扫描对肝脏占位病变患者进行检查，探讨两组方法在肝脏占位病变诊断中的作用。结果本组10例肝细胞癌中9例（90．00％）呈快进快出型强化方式（图1B ），11例肝脏转移瘤中9例（81．82％）呈边缘环形强化，10例肝血管瘤中9例（90．00％）病灶呈渐进性强化，18例肝囊肿动态增强病变均未见强化。M RI与临床病理确诊结果符合率（91．53％）明显高于增强C T ，且差异具有统计学意义。结论 CT、MR联合应用有助于提高肝脏占位性病变诊断水平的提高。     

胰腺囊性病变的CT诊断价值

目的 探讨CT对胰腺囊性病变的诊断价值。资料与方法 分析54例胰腺囊性病变的CT表现，其中假性囊肿41例，真性囊肿2例，浆液性囊腺瘤3例，黏液性囊腺瘤2例，囊腺癌3例，无功能性胰岛细胞瘤3例。结果 41例假性囊肿CT共检出44个囊性病灶，其中41个病灶为单房囊肿，3个病灶囊内见分隔。40个病灶为低密度，4个病灶为略高密度，增强后均无强化。另见。肾前筋膜增厚(32例)、胰周脂肪层模糊(14例)和胰管扩张(6例)。真性囊肿表现为单发或多发无强化囊性病灶，确诊主要依赖特殊临床资料和组织病理学检查。5例囊腺瘤表现为多房分隔囊性肿块，3例浆液囊腺瘤中2例中央见星芒状钙化，增强后分隔有强化。3例囊腺癌表现为多房分隔囊性病灶，其中2例有肝内多发转移。3例无功能胰岛细胞瘤，2例表现为单房囊性病灶，1例表现为多房分隔及囊内出血。结合病变本身及胰腺和胰周改变(包括肝脏)，CT对假性囊肿诊断的准确性为98．1％，对囊性病变诊断的准确性为90．7％。结论 CT能显示病变本身和胰腺及胰周(包括肝脏)形态学改变，有助于胰腺囊性病变的诊断与鉴别诊断。     

肝脏囊性病变的CT和MR诊断

目的 探讨肝脏囊性占位性病变的CT和MR表现及其诊断价值.方法 收集78例肝脏囊性占位性病变的临床及影像学资料,其中炎症性囊性病变21例,肿瘤囊变病例30例,发育性囊肿27例.结果 肝脏囊性病变CT和MR检出率100%.对于炎症性囊性病变﹑肿瘤囊变和发育性囊肿,CT诊断准确率分别是76%、90%和93%,MR诊断准确率分别是83%、93%和100%.CT和MR表现:炎症性囊性病变中,肝脓肿和肝包虫囊肿表现为囊性占位,囊肿有张力,肝脓肿周围大片状低密度影或水样信号影,囊肿内可以形成气液平面.肝包虫囊肿出现大囊套小囊征象,增强检查见囊壁中度强化.肿瘤囊变中,转移瘤平扫表现为肝内多发的囊性病灶,增强检查表现为轻度或中度环形强化.原发肿瘤囊变平扫表现为囊变部分形态不规则,壁厚薄不均,增强检查具有原发肿瘤强化特点.发育性囊肿表现为单发或多发大小不等的低密度或水样信号囊性病灶,一般不强化.结论 CT和MR检查对肝脏囊性病变的定位和定性诊断具有很大价值.     

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。     

胰腺体尾部先天性缺如并胰腺实性-假乳头状瘤1例

女,23岁。体检B超发现胰腺实性占位性病变,无任何临床症状。化验检查无异常。CT检查：胰腺体尾部部分缺如,胰头及胰体部分别可见稍低密度结节,边界清楚,密度均匀,增强扫描呈明显强化（见图1～5）,CT诊断：胰头及体部良性占位性病变（胰腺实性-假乳头状瘤？）。患者行胰腺部分切除术。     

CT在胰腺结核诊断中的价值

目的：探讨胰腺结核的CT征象及其诊断价值。资料与方法：回顾性分析14例胰腺结核的CT表现及临床资料。结果：胰腺结核表现为3型：（1）局灶型：9例，多位于胰头，表现为低密度肿块伴有周边或蜂房状强化；（2）多结节型：4例，胰腺内多发低密度病变，无强化或轻度强化，胰头病变明显，呈蜂房状强化；（3）弥漫型：1例，表现为胰腺弥漫性肿大，边缘模糊。胰腺结核常伴有胰外结核。胰周淋巴结肿大9例，7例增强，呈花环状或环形强化；肝脏受累3例，脾脏受累4例，表现为肝、脾实质内低密度无强化病灶；胆管梗阻、结核性腹膜炎各3例。结论：胰腺结核CT表现多样，包括胰腺局灶性低密度肿块、多发低密度结节或弥漫性胰腺肿大，但最常见的表现是胰腺内局灶性蜂房状强化的肿块。低密度的胰周和门静脉周围淋巴结肿大伴周边环形强化以及其他播散结核灶是支持胰腺结核诊断的重要辅助征象。     

卵巢甲状腺肿的CT和MRI表现

【摘要】目的：卵巢甲状腺肿（SO）临床罕见，且无典型症状和体征，术前容易误诊。本研究分析SO的CT及MR表现，以提高影像诊断水平。方法：回顾性分析10例经手术和病理证实的SO患者的影像学资料，其中7例行CT平扫及增强扫描，3 例行MR平扫及增强扫描。结果：10例SO均为单侧发病，右侧6例，左侧4例；其中囊实性7例，囊性2例，实性1例；肿瘤最大径1.4~15.6cm，平均（7.7±3.9）cm。 ①CT表现：7例CT检查病变均表现包膜完整，2例伴钙化。5例囊实性病变实性部分明显强化，CT值79~145HU；1例囊性病变内含圆形高密度区，CT值65~98HU，增强后无强化；1例实性病变明显强化，CT值128HU。②MR表现：3例MR检查病变中，2例囊实性病变实性部分T1WI等信号，T2WI稍高信号，增强后明显强化，囊性部分T1WI呈低信号，T2WI呈高信号，增强未见强化；1例囊性病变T1WI呈低信号，T2WI呈高信号，病变内见类圆形极低信号区。结论:卵巢甲状腺肿的MRI、CT 表现具有一定特征性，有助于诊断及鉴别诊断。     

自身免疫性胰腺炎的MR诊断与鉴别诊断

目的分析自身免疫性胰腺炎的MRI表现,旨在提高对其诊断的准确率。方法对经临床证实的10例自身免疫性胰腺炎进行回顾性分析,10例均行MR平扫及增强扫描检查。结果胰腺弥漫性受累(8/10),胰头局限性肿块(1/10),胰体尾部受累(1/10);6例可见"假包膜"征。MRCP:9例胆总管胰腺段狭窄,8例见胰管局限性或弥漫性狭窄,1例主胰管未见显示;动态增强后病变区呈延迟性强化。结论 MRI表现有一定的特点,需要和其它胰腺病变进行鉴别诊断,从而做出正确的诊断。     

磁共振多b值DWI对肝脏局灶性占位性病变的应用价值

目的：探讨磁共振多b值扩散加权成像技术在肝脏局灶性占位性病变中的应用价值。方法：分析经手术病理或其他方式确诊的肝脏局灶性占位性病变22例（49个病灶）,其中肝癌6例（10个病灶）,肝转移瘤6例（23个病灶）,肝囊肿5例（8个病灶）,肝血管瘤5例（8个病灶）。同时选择10名健康志愿者作为对照。以上患者及正常志愿者均进行磁共振常规轴面T1WI、T2WI以及多b值扩散加权成像。记录各病变不同b值时各病变的信号强度,观察各个病变b值-信号强度曲线和b值-ADC值曲线的差异。结果：正常肝实质随着b值增加,信号持续较低;囊肿在b值=0 s/mm2时具有很高的信号强度,随着b值的增加,其信号很快减低;而肝癌及转移性肿瘤随着b值增加,一直保持较高信号,在b值〉900s/mm2后病灶信号强度高于囊肿;肝脏血管瘤信号强度则介于囊肿与肝脏肿瘤之间。结论：磁共振多b值扩散加权成像技术可为鉴别肝脏良恶性局灶性占位性病变提供重要依据。     

MnDPDP-enhanced MRI vs dual-phase spiral CT in the detection of hepatocellular carcinoma in cirrhosis

The objectives of this study were twofold: (a) to assess safety and tolerability of the hepatobiliary MR contrast agent MnDPDP; and (b) to investigate the sensitivity of MnDPDP-enhanced MRI, in comparison with dual-phase spiral CT, in the detection of hepatocellular carcinoma (HCC) in cirrhosis. Fifty patients with liver cirrhosis and histologically proven HCC were enrolled in a prospective phase-IIIB clinical trial. All patients underwent evaluation with dual-phase spiral CT and pre-contrast and post-contrast MRI at 1.5 T. The MR examination protocol included spin-echo (SE) and gradient-recalled-echo (GRE) T1-weighted images acquired before and 60–120 min after administration of 0.5 μmol/kg (0.5 ml/kg) MnDPDP (Teslascan, Nycomed Amersham, Oslo, Norway); and fast T2-weighted SE images obtained solely before contrast injection. Gold standard was provided by findings at Lipiodol CT in combination with follow-up spiral CT studies, which were repeated at 4-month intervals over a 10- to 27-month (mean ± SD 20.1 ± 5.1 months) follow-up period. No serious adverse event occurred. Eighty tumors ranging 0.8–9.1 cm in diameter (mean ± SD 3.2 ± 2.4 cm) were detected by Lipiodol CT or confirmed as cancerous foci by follow-up CT studies. Pre-contrast MRI detected 38 of 80 lesions (48 %); MnDPDP-enhanced MRI, 65 of 80 lesions (81 %); pre-contrast plus post-contrast MRI, 69 of 80 lesions (86 %); and dual-phase spiral CT, 64 of 80 lesions (80 %). The difference between unenhanced and MnDPDP-enhanced MRI was statistically significant (p < 0.001). The difference between MRI (pre-contrast plus post-contrast) and dual-phase spiral CT was not statistically significant (p = 0.33). The confidence in the final diagnosis, however, was significantly higher for MRI as compared with spiral CT (p < 0.001). MnDPDP is a safe and well-tolerated hepatobiliary MR contrast agent. Magnetic resonance imaging with use of MnDPDP is significantly more sensitive than unenhanced MRI and as good as dual-phase spiral CT for detection of HCC in cirrhosis. Received: 29 February 2000; Revised: 8 June 2000; Accepted: 9 June 2000     

背景抑制磁共振弥散成像(D WIBS)技术在肝脏局灶性占位性病变中的初步应用

目的:探讨背景抑制磁共振弥散成像(DWIBS)技术在肝脏局灶性占位性病变中的应用价值。方法:回顾性分析肝脏局灶性占位性病灶25例49个。其中肝细胞癌9例12灶,肝转移瘤6例18灶,肝囊肿7例16灶,肝血管瘤3例3灶的背景抑制磁共振弥散成像(b=600s/mm2),测量各病灶的表观弥散系数(ADC)值并进行比较,利用3D-MIP重建及黑白翻转技术,观察病变显示效果。结果:在b=600s/mm2的图像中,肝脏恶性肿瘤多表现为高信号;肝脏良、恶性肿瘤间差异具有统计学意义(P<0.05);肝细胞癌与肝转移瘤组间、肝囊肿与肝血管瘤组间无统计学差异(P>0.05)。背景抑制的DWI经MIP重建及黑白翻转技术,病变周围组织信号被抑制,得到类PET图像,25例49个病灶,均清晰显示。结论:背景抑制磁共振弥散加权成像在显示病灶方面有一定优势;应用DWI结合ADC值对于肝脏良、恶性占位病变有一定鉴别价值。     

The value of MnDPDP enhancement during MR guided laser interstitial thermoablation of liver tumors

Magnetic resonance (MR)-guided thermal ablation procedures are feasible in modern open low field strength MR scanners. The compromises for rapid imaging in this configuration worsen liver lesino conspicuity. To overcome this, we utilize liver-specific contrast Mangafodipir Trisodium (MnDPDP) to improve lesion recognition and targeting and allow a longer contrast-assisted window. Three observers assessed pre- and post-contrast MR scans of 14 liver ablation patients. They assessed the number of lesions, ease of puncture planning, conspicuity of lesions, gallbladder, vessels, and surrounding bowel. There was a significant improvement in lesion conspicuity and ease of puncture planning when MnDPDP was used. In two of the observers, there was also a significant improvement in the number of lesions seen and in bowel conspicuity. No significant difference was shown in the detection of the gallbladder or vessels. We conclude that the liver-specific contrast agent MnDPDP improves the overall accuracy and safety of MR-guided thermal ablation of liver tumors facilitating this procedure at lower field strengths. J. Magn. Reson. Imaging 2001;13:37-41.     

Detection of liver metastases in colorectal cancer on chemotherapy. Comparative study between MRI with teslascan and computed tomography with intravenous contrast media

OBJECTIVE: To compare MRI of the liver with mangafodipir trisodium (MnDPDP) and computed tomography with intravenous contrast media in the follow-up of liver metastases in patient on chemotherapy for colorectal carcinoma. MATERIALS AND METHODS: This was a prospective study with patients on chemotherapy for liver metastases from colorectal cancer. Patients underwent both contrast-enhanced helical CT using 2 cc/kg contrast at 3 cc/sec and mangafodipir trisodium-enhanced MR imaging at 1.5 T using 2-3 cc/min contrast at 5 micro mol/kg within a two week interval. Two experienced radiologists independently reviewed all scans in a blinded fashion and recorded image quality as well as presence and number of liver lesions. Statistical analysis was performed using the wilcoxon signed rank test. RESULTS: All examinations were of good quality. A total of 71 lesions were detected at CT, with 69 lesions consistent with metastases and 2 lesions consistent with cysts. A total of 98 lesions were detected at MRI, with 97 consistent with metastases and 1 lesion consistent with a cyst. T1 weighted images with MnDPDP significantly detected two additional lesions compared to CT (p<0.05). No significant difference was demonstrated between T1 weighted images without MnDPDP and CT or between T2 weighted images and CT. CONCLUSION: Magnetic resonance imaging with MnDPDP is significantly more sensitive than unenhanced MRI and helical CT for the follow-up of liver lesions.     

Intraoperative US in patients undergoing surgery for liver neoplasms: comparison with MR imaging

PURPOSE: To retrospectively compare intraoperative ultrasonography (US) and preoperative magnetic resonance (MR) imaging with contrast material enhancement for the depiction of liver lesions in patients undergoing hepatic resection. MATERIALS AND METHODS: A radiologist (D.V.S.) and a surgeon (K.K.T.) retrospectively identified 79 patients (36 female and 43 male patients; age range, 10-78 years; mean age, 57 years) who had undergone surgical resection for primary liver tumor or metastasis and had also undergone preoperative contrast-enhanced MR imaging within 6 weeks before surgery. MR imaging was performed with a 1.5-T system. Dedicated intraoperative US of the liver was performed or supervised by a gastrointestinal radiologist using a 7.5-MHz linear-array transducer, after adequate hepatic mobilization by the surgeon. Histopathologic evaluation of the 159 resected hepatic lesions served as the reference standard. The lesion distribution included colon cancer metastasis (n = 122), hepatocellular carcinoma (n = 23), cholangiocarcinoma (n = 6), cavernous hemangioma (n = 4), focal nodular hyperplasia (n = 2), hamartoma (n = 1), and metastatic embryonal sarcoma (n = 1). RESULTS: Of 159 lesions, 138 (86.7%) were identified at both MR imaging and intraoperative US. Twelve additional lesions (7.5%) in 10 patients were detected only at intraoperative US (eight metastases, one hepatocellular carcinoma, one cholangiocarcinoma, one hemangioma, and one biliary hamartoma). Both modalities failed to depict nine lesions (5.6%) (four metastases, four hepatocellular carcinomas, and one cholangiocarcinoma). The sensitivities of MR imaging and intraoperative US for liver lesion depiction were 86.7% and 94.3%, respectively. Surgical management was altered on the basis of the intraoperative US findings in only three of 10 patients (4%). CONCLUSION: Contrast-enhanced MR imaging is as sensitive as intraoperative US in depicting liver lesions before hepatic resection.     

Detection and characterization of focal hepatic lesions: mangafodipir vs. superparamagnetic iron oxide-enhanced magnetic resonance imaging

PURPOSE: To compare the mangafodipir-enhanced magnetic resonance (MR) and superparamagnetic iron oxide (SPIO)-enhanced images for their ability to detect and characterize focal hepatic lesions. MATERIALS AND METHODS: Unenhanced, mangafodipir-enhanced, and SPIO-enhanced hepatic MR images obtained from 64 patients were analyzed. A total of 121 hepatic lesions were included: 66 hepatocellular carcinomas (HCCs), 26 metastases, 14 hemangiomas, 5 cysts, 3 cholangiocarcinomas, 4 focal nodular hyperplasias (FNHs), 2 abscesses, and 1 adenoma. Two radiologists independently reviewed the two sets of images in a random order: 1) the unenhanced and mangafodipir-enhanced images (the mangafodipir set) and 2) the unenhanced and SPIO-enhanced images (the SPIO set). This study compared the accuracy of lesion detection, the ability to distinguish between a benign and malignant lesion, and the ability to distinguish between the hepatocellular and nonhepatocellular origins of the lesions using the areas (Az) under the receiver operating characteristic (ROC) curve. RESULTS: The overall accuracy for detecting focal lesions was significantly higher (P < 0.05) with the SPIO set (Az = 0.846 and 0.871 for readers 1 and 2, respectively) than with the mangafodipir set (Az = 0.716 and 0.766). Most of the lesions detected only with the SPIO-enhanced MR images by the readers were small HCCs. For lesions larger than 15 mm, the sensitivities of the two contrast enhancement techniques were similar for both readers. The accuracy of the mangafodipir and SPIO sets in distinguishing between benign and malignant lesions was comparable. The accuracy for distinguishing between the hepatocellular and nonhepatocellular origins of the lesions was significantly higher (P < 0.05) using the mangafodipir set (Az = 0.897 and 0.946) than using the SPIO set (Az = 0.741 and 0.833). CONCLUSION: SPIO- and mangafodipir-enhanced images were comparable for detection of focal hepatic lesions other than small HCCs, which were better detected on the SPIO-enhanced images. Mangafodipir-enhanced images are likely better than the SPIO-enhanced images for distinguishing between focal liver lesions with a hepatocellular or nonhepatocellular origin.     

Magnetic resonance with manganese-DPDP (mangafodipir) of focal solid pancreatic lesions

PURPOSE: To assess the accuracy of magnetic resonance (MR) with Mangafodipir (Mn-DPDP) in the identification of focal solid pancreatic lesions. The possibility of lesion characterisation based on quantification of Mn uptake was also investigated. MATERIALS AND METHODS: Thirty-four patients (11 females, 23 males, aged 21-75, mean age 57) selected at sonography (US) and spiral CT (SCT) for clinically suspected focal solid pancreatic lesion, were studied between June 2000 and July 2001. Patients eligible for surgery underwent MR imaging (1.5 T) before and after infusion of 5 micromol/kg of Mn-DPDP (0.5 ml/kg Teslascan, Nycomed Amersham Health, Oslo, Norway). The baseline examination included FSE T2-weighted sequences and fat-saturated and non fat-saturated breath-hold gradient-echo T1-weighted sequences (FMP SPGR). After Teslascan infusion, fat-saturated and non fat-saturated FMP SPGR sequences were repeated. Thirty of the 34 patients had a definitive diagnosis provided by reference standards such as post-operative histology (22 cases), cytology (FNAB) and/or a follow-up period of at least 6 months (8 patients). As regards lesion characterisation, the signal-to-noise ratio (S/N ratio) and contrast-to-noise ratio (C/N ratio) of lesions compared to the pancreatic parenchyma were calculated using ROIs before and after contrast infusion. RESULTS: The definitive diagnosis was pancreatic malignancy in 18 patients, focal pancreatitis in 5 and neuroendocrine tumours in 3. Four patients with suspected lesions at US and/or SCT were free of focal pancreatic disease. Mn-DPDP MR identified 17/18 malignancies, 2/3 endocrine neoplasms 5/5 focal pancreatitis; the 4 patients with no pancreatic lesions were correctly identified. The Mn-DPDP MR accuracy in detecting focal pancreatic solid lesions was 93%. MR missed 1 small adenocarcinoma (the only pT1 in our group) and 1 insulinoma (with Mn uptake similar to the surrounding parenchyma). Due to the small number of inflammatory lesions included in the study, no significant differences were found in signal intensity and Mn-DPDP uptake between focal pancreatitis and neoplasms. CONCLUSIONS: MR with Mn-DPDP is very accurate in the identification of focal solid pancreatic lesions. Mangafodi-pir is also very useful for excluding the presence of pancreatic lesions suspected at US or CT. The characterisation of lesions, in particular of inflammatory versus neoplastic lesions, remains problematic and requires further investigation.     

Conspicuity of hepatocellular nodular lesions in cirrhotic livers at ferumoxides-enhanced MR imaging: importance of Kupffer cell number

PURPOSE: To correlate the conspicuity of hepatocellular carcinomas and dysplastic nodules on ferumoxides-enhanced magnetic resonance (MR) images with the number of Kupffer cells in the hepatic lesions, as compared with that in background liver in histopathologic findings. MATERIALS AND METHODS: Sixty-nine histopathologically proved moderately or poorly differentiated hepatocellular carcinomas, 10 well-differentiated hepatocellular carcinomas, and 19 dysplastic nodules were retrospectively studied in 68 patients with cirrhosis who underwent ferumoxides-enhanced MR imaging. The contrast-to-noise ratio between the nodules and surrounding parenchyma was calculated at T2-weighted fast spin-echo imaging, and the difference in the number of Kupffer cells between the nodules and surrounding hepatic tissue was calculated histopathologically. The results of MR imaging and histopathologic examination were correlated. RESULTS: All 69 moderately or poorly differentiated hepatocellular carcinomas had high contrast-to-noise ratios at MR imaging and large differences in the number of Kupffer cells. Six of the 10 well-differentiated hepatocellular carcinomas had contrast-to-noise ratios of zero or nearly zero, and five of these had little difference in the number of Kupffer cells. All 19 dysplastic nodules had contrast-to-noise ratios of zero or nearly zero, and there were virtually no differences in the number of Kupffer cells. CONCLUSION: Hepatocellular nodule conspicuity at ferumoxides-enhanced MR imaging depends on differences in the number of Kupffer cells within a nodule and the surrounding cirrhotic liver; moderately or poorly differentiated hepatocellular carcinomas can be distinguished from well-differentiated hepatocellular carcinomas and dysplastic nodules.