磁共振扩散加权成像在肝脏疾病中的应用

磁共振扩散加权成像是一种可反映活体内水分子扩散特征的功能成像方法,能间接反映细胞的密度和细胞膜的完整性及毛细血管灌注情况。介绍了该技术在肝脏病变中的主要应用,并重点介绍其在肝细胞癌、肝纤维化的分期及肿瘤疗效监测中的应用。指出这种无需注射对比剂的技术虽仍有不足,但随着软、硬件的发展,将有广阔的应用前景。     

磁共振弥散张量成像在神经疾病中的应用

磁共振弥散张量成像(DTI)是近几年发展起来的水弥散成像技术,它通过脑水分子的弥散性定量反映脑白质纤维束的完整性。文章简要介绍了DTI的基本概念及其在脑梗死、多发性硬化、癫、Alzheimer病和颅内肿瘤等多种神经疾病中的应用。     

磁共振弥散张量成像在神经疾病中的应用

磁共振弥散张量成像（DT）是近几年发展起来的水弥散成像技术，它通过脑水分子的弥散性定量反映脑白质纤维束的完整性。文章简要介绍了DTI的基本概念及其在脑梗死、多发性硬化、癫痫、Alzheimer病和颅内肿瘤等多种神经疾病中的应用。     

磁共振弥散成像在脑卒中临床应用中的新进展

弥散磁共振扫描的综合表现弥散常数（ＡＤＣ）可早期、数字化地研究脑卒中血后的脑组织变化。文章讨论弥散常数（Ｄ）值在动物实验及脑座中临床运用的进展。     

超声造影在肝癌肝移植术后肝转移癌射频消融治疗之中的应用

目的通过临床总结,评价超声造影(CEUS)在射频消融治疗肝癌肝移植术后肝转移癌中应用的优点。方法采用超声造影辅助诊断定位经皮穿刺射频消融(RFA)治疗肝癌肝移植术后2～12月肝转移癌灶12例,癌灶直径12 mm～45 mm,每个病灶通过超声造影诊断定位进行RFA 1～2次,术后通过超声造影及增强CT评价疗效。结果11例病灶术后1月后复查,示全部消融,1例较大病灶治疗后有部分残余,行再次射频,1月后复查病灶坏死。结论超声造影应用于RFA治疗肝癌肝移植术后肝转移癌发现早,诊断早,定位准确,效果好,操作简便易行,微创无严重并发症,进一步提高了超声引导下RFA的准确率和疗效。     

弥散加权磁共振与磁共振血管成像在急性脑梗死诊断中的临床应用

目的　评价弥散加权磁共振成像 (Diffusion -weightedimaging ,DWI)及磁共振血管成像 (MagneticReso nanceAngiography ,MRA)在脑梗死早期的临床应用价值。 方法　对 3 0例急性脑梗死患者行DWI和MRA检查 ,并与CT、常规MRI的结果进行分析比较。结果　在超早期及早期急性脑梗死中DWI可显示CT及T2 WI不能显示的病灶 ,对于T2 WI能显示的病灶DWI能更清楚、更全面的显示该病灶 ,MRA能快速发现血管病变的部位和程度。结论　DWI与MRA对急性脑梗死的早期诊断十分敏感 ,联合检查可同时显示脑实质和脑血管情况 ,为早期溶栓治疗提供了切实可行的影像学资料     

肝移植术后胆管狭窄的防治

34例同种异体原位肝移植术患者,术后发生胆管狭窄4例。均曾行内镜、鼻胆管引流、球囊扩张、内支架置入治疗;其中2例行二次肝移植术,1例行胆肠吻合术．1例持续行内镜治疗。该并发症重在预防,一旦发生可采用上述不同方法治疗。     

磁共振血管造影在脑血管疾病中的应用

磁共振血管适影与常规磁共振成像检查相结合,可提高脑血管疾病的诊断准确率,而总的检查时间仅稍有延长,它可用于颅内动脉瘤、动脉闭塞性疾病、血管畸形与硬膜窦闭塞的诊断,也可用于颅外颈动脉(特别是颈动脉分叉处)病变的检查。     

磁共振弥散加权成像在肝硬化诊断中的应用

目的探讨磁共振弥散加权成像对肝硬化的诊断价值。方法采用GEHDx1．5TMRI扫描仪对100例临床诊断肝硬化患者（肝硬化组）及30名健康对照者（对照组）行轴位屏气弥散加权成像扫描（扩散敏感系数b值选用800mm^2／s）,比较2组表观弥散系数（apparent diffusion coefficient。ADC）值。结果对照组与肝硬化组肝脏ADC值分别为（1．842±0．173）和（1．380±0．137）×10^-3mm^2/s,后者低于前者,2组差异有统计学意义。结论肝硬化患者肝脏ADC值下降,磁共振弥散加权成像可望成为无创肝硬化诊断的手段之一。     

胆管腔内超声与逆行胆管造影诊断胆管结石的对比研究

目的 比较十二指肠镜下胆管腔内超声（IDUS）和内镜下逆行胆管造影（ERC）诊断肝外胆管结石的作用。方法 对30例临床怀疑有肝外胆管结石的患者，先进行ERC，再经内镜活检孔道将超声微探头直接送入胆管腔内探查，而后行乳头切开取石。结果 30例患者中，ERC准确诊断结石26例，将胆管絮状物诊断为结石1例，漏诊2例，其诊断结石的准确率，敏感性分别为86.7%(26/30),92.9%(26/28)；而IDUS准确诊断结石28例，无漏诊，误诊，其诊断结石的准确率，敏感性均为100.0%。结论 IDUS可弥补ERC的视觉误差且在确定胆管结石方面优于ERC。     

磁共振扩散加权成像对肝脏局灶病变的价值

目的:探讨磁共振扩散加权成像(diffusion weighted imaging,DWI)对肝脏局灶性病变诊断和鉴别诊断的价值.方法:原发性肝癌30例,肝血管瘤12例,肝囊肿13例,正常肝36例,行常规MRI检查加DWI,b值取500 s/mm~2和800 s/mm~2,利用MRI工作站软件Functool 2.6.6i,500 s/mm~2扫描的图像得到ADC图及eADC图,800 s/mm~2扫描的图像测出mADC,eADC及瘤肝ADC比值及瘤肝eADC比值等指标,利用SPSS12.0软件进行统计学处理.结果:mADC值正常肝(1.89±0.62 10.2 mm~2/s)低于肝囊肿与肝血管瘤(2.93±0.46 10~(-3)mm~2/s,2.26±0.45 10~(-3)mm~2/s,P<0.01,P<0.05)而高于原发性肝癌(1.43±0.52 10~(-3)mm~2/s,P<0.01);肝囊肿高于肝血管瘤(P<0.01)与原发性肝癌(P<0.01);肝血管瘤高于肝细胞癌(P<0.01).eADC值正常肝高于肝囊肿而低于肝血管瘤与原发性肝癌(0.1 55±0.07 vs 0.052±0.03,0.23±0.10,0.31±0.22,P<0.05,P<0.05,P<0.01);肝囊肿低于肝血管瘤(P<0.01)与原发性肝癌(P<0.01);肝血管瘤低于肝细胞癌(P<0.01).瘤肝ADC比值肝囊肿高于肝血管瘤与原发性肝癌(1.93±0.43 vs 1.43±0.44,0.95±0.45,均p0<.01);肝血管瘤高于原发性肝癌(P<0.01),瘤肝eADC比值在不同组间比较:肝囊肿低于肝血管瘤与原发性肝癌(1.00±0.57 vs 1.63±0.36,1.46±0.74,P<0.01,P<0.05);肝血管瘤高于原发性肝癌,但无显著性差异(P>0.05).结论:DWI有利于显示肝脏病变,综合运用mADC和eADC可进一步提高鉴别诊断的正确率.     

肝移植术后胆道并发症的磁共振评价

目的:探讨磁共振胰胆管成像(MRCP)联合MR断面图像在诊断肝移植术后胆道并发症中的应用价值.方法:对57例肝移植术后怀疑有胆道并发症的患者行MR检查,分析其表现,并与手术、胆道造影、肝脏活检和,临床随访结果进行对照.比较MRCP和MRCP联合MR断面图像对胆道并发症诊断的确诊率.结果:57例患者胆道并发症发生率64.9%(37/57).其中吻合口狭窄患者14例,非吻合口狭窄8例.孤立性胆道结石或胆泥淤积5例,胆管炎及胆管周围炎3例,胆汁湖/胆汁瘤3例,供体-受体胆总管不匹配3例,肝外胆管吻合后过长1例.对胆道并发症诊断的准确率,MRCP为75.7%(28/37),MRCP联合MRI断面图像为94.6%(35/37),两者差别有统计学意义(P<0.05).结论:MRCP联合MR断面图像能提高胆道并发症诊断的准确性.     

Role of diffusion-weighted magnetic resonance imaging in the diagnosis of extrahepatic cholangiocarcinoma

AIM: To determine the clinical value of diffusion-weight- ed imaging (DWI) for the diagnosis of extrahepatic cholangiocarcinoma (EHCC) by comparing the diagnostic sensitivity of DWI and magnetic resonance cholan-giopancreatography (MRCP). METHODS: Magnetic resonance imaging examination was performed in 56 patients with suspected EHCC. T1- weighted imaging, T2-weighted imaging, MRCP and DWI sequence, DWI using single-shot spin-echo echoplanar imaging sequence with different b values (100, 300, 500, 800 and 1...     

磁共振增强扫描弥散加权成像对肝脏良恶性肿瘤的鉴别诊断价值研究

目的 探讨磁共振增强扫描联合扩散加权成像(DWI)对肝脏良恶性病变鉴别诊断的临床价值.方法 在80例肝脏局灶性病变患者接受3.0T磁共振成像(MRI)增强和DWI序列扫描,并接受手术治疗.以组织病理学检查结果为"金标准",评估MRI和DWI的诊断效能.结果 在本组80例肝脏局灶性病变患者中,术后组织病理学诊断肝细胞癌2...     

成人肝移植术后新生未分化性肝肉瘤1例

未分化性肝肉瘤(undifferentiated sarcomaoftheliver,UESL)多发生于6～10岁的儿童,误诊率高,成人少见,肝移植术后发生更为罕见[1].我院收治了1例肝移植术后新生UESL成年患者,现报道如下.     

Postoperative biliary adverse events following orthotopic liver transplantation: Assessment with magnetic resonance cholangiography

Biliary adverse events following orthotopic liver transplantation (OLT) are relatively common and continue to be serious causes of morbidity, mortality, and transplant dysfunction or failure. The development of these adverse events is heavily influenced by the type of anastomosis during surgery. The low specificity of clinical and biologic findings makes the diagnosis challenging. Moreover, direct cholangiographic procedures such as endoscopic retrograde cholangiopancreatography and percutaneous transhepatic cholangiography present an inadmissible rate of adverse events to be utilized in clinically low suspected patients. Magnetic resonance (MR) maging with MR cholangiopancreatography is crucial in assessing abnormalities in the biliary system after liver surgery, including liver transplant. MR cholangiopancreatography is a safe, rapid, non-invasive, and effective diagnostic procedure for the evaluation of biliary adverse events after liver transplantation, since it plays an increasingly important role in the diagnosis and management of these events. On the basis of a recent systematic review of the literature the summary estimates of sensitivity and specificity of MR cholangiopancreatography for diagnosis of biliary adverse events following OLT were 0.95 and 0.92, respectively. It can provide a non-invasive method of imaging surgical reconstruction of the biliary anastomoses as well as adverse events including anastomotic and non-anastomotic strictures, biliary lithiasis and sphincter of Oddi dysfunction in liver transplant recipients. Nevertheless, conventional T2-weighted MR cholangiography can be implemented with T1-weighted contrast-enhanced MR cholangiography using hepatobiliary contrast agents (in particular using Gd-EOB-DTPA) in order to improve the diagnostic accuracy in the adverse events’ detection such as bile leakage and strictures, especially in selected patients with biliary-enteric anastomosis.     

Role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of focal hepatic lesions

AIM: To evaluate the utility of diffusion-weighted imaging (DWI) in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS: Magnetic resonance imaging (MRI) examinations were performed using the Signa Excite Xl Twin Speed 1.5T system (GE Healthcare, Milwaukee, WI, USA). Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas (HCC), four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio (RCR), and apparent diffusion coefficient (ADC) were compared between benign and malignant lesions on DWI. Superparamagnetic iron oxide (SPIO) was administered to 59 patients, and RCR was compared pre- and postadministration. RESULTS: DWI showed higher contrast between malignant lesions (especially in multiple small metastatic cancers) and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs (mean ± SD × 10~(-3) mm~2/s) were significantly lower ( P < 0.05) in malignant lesions (HCC: 1.31 ± 0.28 and liver metastasis: 1.11 ± 0.22) and were significantly higher in benign lesions (hemangioma: 1.84 ± 0.37 and cyst: 2.61 ± 0.45) than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding hepatic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved. CONCLUSION: DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.     

原位肝移植术后胆道并发症诊治134例

目的:探讨原位肝移植术后胆道并发症的预防和治疗.方法:回顾性分析2004-10/2006-01施行的134例肝移植患者的临床资料.结果:18例患者(共20例次)出现胆道并发症,治愈17例,1例放弃治疗.其中胆道狭窄12例次,胆漏2例次,胆管结石6例次.与T管相关的胆道并发症发生率为11.7%(14/120).胆道并发症组冷缺血时间(624min)和二次热缺血时间(60min)均高于无胆道并发症组(384min,43min,均P<0.05).结论:保存性损伤和缺血性损伤是肝移植术后胆道并发症的重要原因.术后早期胆道造影并联合应用核磁共振胆管成像有助于及时诊断胆道并发症.介入技术是胆道并发症的主要治疗手段.     

Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.METHODS: Forty-two patients were included in the study. On MRE, mean stiffness values were measured on the elastograms in kilopascals. The apparent diffusion coefficient (ADC) of the liver was measured using DWI. On gadoxetic acid enhanced MR, the contrast enhancement index (CEI) was calculated as signal intensity (SI)_post/SI_pre, where SI_post is liver-to-muscle SI ratio on hepatobiliary phase images and SI_pre is that on nonenhanced images. Correlation between aspartate aminotransferase to the platelet ratio index (APRI) and three MR parameters was assessed. Each MR parameter was compared between a hepatic fibrosis (HF) group and non-hepatic fibrosis (nHF) group.RESULTS: Liver stiffness showed strong positive correlation with APRI [Spearman correlation coeffiecient (r) = 0.773, P < 0.0001], while ADC and CEI showed weak or prominent negative correlation (r = -0.28 and -0.321, respectively). In the HF group, only liver stiffness showed strong correlation with APRI (r = 0.731, P < 0.0001). Liver stiffness, ADC, and APRI were significantly different between the HF group and nHF group.CONCLUSION: MRE at 3-Tesla could be a feasible method for the assessment of hepatic fibrosis.