MR 动态增强联合扩散加权成像对壶腹区良恶性病变的鉴别

目的：研究M R动态增强联合扩散加权成像（DWI）在鉴别壶腹区良恶性病变的价值。方法回顾性分析43例胆总管下段狭窄患者的M R动态增强及DWI的数据。其中包括32例恶性病变和11例慢性炎症。1位影像医生对壶腹周围良恶性病变的M R动态增强信号强度及DWI信号进行分析,另外2位影像医生对壶腹周围病变的M R动态增强影像以及M R动态增强联合DWI影像进行评估。应用 Logistic回归分析比较灵敏度及特异性。结果壶腹周围良恶性病变MR动态增强表现差异无统计学意义;DWI影像中,壶腹周围癌比炎症更多地表现为高信号,表观扩散系数（ADC）图表现为低信号（P＜0．001）。2位读片者在结合DWI影像后对恶性壶腹周围病变的诊断灵敏度均有提高,分别从84．4％提高到96．9％和从87．7％提高到96．6％。结论 M R动态增强联合DWI可提高鉴别壶腹周围区良恶性狭窄的诊断准确率。     

MR胰胆管成像加常规扫描在鉴别胆道术后病变良恶性上的意义

目的　探讨MR胰胆管成像 (MRCP)加常规扫描在鉴别胆道术后病变良恶性上的意义。方法　对 61例胆道术后出现不明原因发热、黄疸、右上腹痛等症状患者进行MRCP检查 ,同时行MR平扫及增强扫描 ,2位医师使用 3种不同的序列组合 (MRCP、MRCP +平扫、MRCP +平扫 +增强扫描 )独立对病变的良、恶性作出诊断。诊断结果分别与手术、病理结果对照。结果　对病变良恶性的诊断 ,仅用MRCP ,医师 1诊断的敏感度、特异度、准确度分别为 42 1%、80 9%、68 9% ,医师 2分别为47 4%、85 7%、73 8%。使用MRCP +平扫 ,医师 1诊断的敏感度、特异度、准确度分别为 78 9%、92 9%、88 5 % ,医师 2分别为 78 9%、95 2 %、90 2 %。使用MRCP +平扫 +增强扫描 ,医师 1诊断的敏感度、特异度、准确度分别为 84 2 %、95 2 %、91 8% ,医师 2分别为 84 2 %、97 6%、93 4%。MRCP +平扫的ROC曲线Az值 (医师 1为 0 90 7,医师 2为 0 92 0 ) ,较MRCP的ROC曲线下的面积 (Az值 ) (医师 1为 0 682 ,医师 2为 0 714)显著增大 (P <0 0 5 ) ,MRCP +平扫 +增强扫描的ROC曲线Az值 (医师 1为0 948,医师 2为 0 944 )较MRCP +平扫的ROC曲线Az值增大 ,但无显著性差异 (P >0 0 5 )。结论MRCP加MR常规扫描有助于鉴别病变的良恶性 ,提高术后病变     

T2*-PWI联合DCE-MRI及DWI对乳腺病变的诊断价值

目的:探讨T2*加权灌注成像联合动态增强磁共振成像(DCE-MRI)、磁共振弥散加权成像(DWI)对乳腺良恶性病变鉴别诊断的价值.方法:3.0T MRI系统对64例乳腺病变患者依次行常规的MRI平扫、T2*-PWI、DCE-MRI和DWI检查.通过统计学分别评价DCE-MRI,DCE-MRI及DWI,T2*-PWI及DCE-MRI,T2*-PWI、DCE-MRI及DWI 4种方法对乳腺良恶性病变的诊断价值.结果:DWI、T2*PWI及DCE-MRI组合模式具有较高的诊断价值,其敏感度、特异度、准确度、ROC曲线下面积(AUC)分别为97.8％、88％、94.2％、0.929.结论:T2*-PWI有助于乳腺良恶性病的鉴别诊断,具有较高的特异性.T2*-PWI联合DCE-MRI、DWI该种组合模式可明显提高MRI对乳腺良恶性病变诊断的价值,具有较高的准确性、特异性.     

MRCP对诊断良恶性胆道梗阻的临床应用

目的 评价磁共振胰胆管成像(MRCP)对良恶性胆管梗阻的诊断价值。方法25例经病理证实的良恶性胆道梗阻包括胆囊及胆道结石10例,单纯胆囊结石3例,胆总管囊肿合并结石1例,壶腹及胰头癌6例,肝门癌3例,以及胆囊癌2例的MRCP表现进行了回顾性分析。MRCP检查是以PHILIPS GYROSCAN NT 1．0磁共振成像仪并用3D-FSE序列和常规SE序列进行的。结果在所有病人中成功地进行了MRCP检查。其表现随病变性质与部位不同而异,如肝内胆管明显扩张且呈软藤状见于肝门癌。胆总管横行截断,断端形态规则见于胆管上段腺癌。胆总管明显增宽呈壶腹状,胆囊明显增大见于胆总管囊肿。结论MRCP应成为诊断良恶性胆道梗阻的推荐方法。     

MRCP结合薄层T2WI对壶腹周围病变的诊断价值

目的探讨MRCP及薄层轴位T2WI脂肪抑制序列对壶腹周围病变的定性诊断价值。方法收集2005-11—2007-11行磁共振检查,同时对感兴趣区行薄层扫描且临床资料完整的壶腹周围病变95例,总结其轴位MRI及MRCP的征象特征,比较增加薄层扫描前后诊断准确率。结果经手术病理或ERCP证实胰头癌27例,壶腹周围癌30例,壶腹区结石38例,MRCP结合常规MRI对病变诊断的准确率为75.79%,增加薄层扫描后准确率为92.63%,二者之间差异有统计学意义(χ2=10.13,P<0.01)。结论薄层扫描可提高壶腹周围病变的诊断准确率,有助于小结石、小肿瘤的鉴别诊断。     

高场MRI动态增强联合MRCP在肝外癌性梗阻性黄疸中的应用

目的:探讨MRI动态增强联合MRCP在肝外癌性梗阻性黄疸中的临床应用价值.方法:对30例梗阻性黄疸患者在常规MR扫描基础上行MRCP检查及LAVA多期动态增强扫描,观察病变征象并与病理结果对照.结果:30例患者均经病理证实,包括胆管癌15例、壶腹癌5例、胰头癌7例、壶腹周围十二指肠癌1例、胆囊癌2例,其中1例胰头癌漏诊,2例胆管癌和1例壶腹癌误诊为炎症,病灶定性诊断准确率和组织起源诊断准确率分别为86.7％、93.3％.结论:高场MRI动态增强和MRCP技术的联合应用能为肝外癌性胆道梗阻的早期诊断、鉴别诊断提供重要信息,具有很高的临床应用价值.     

扩散峰度成像与DWI在卵巢实性病灶良恶性鉴别诊断中的应用

目的:探讨扩散峰度成像(DKI)与DWI在卵巢实性病灶良恶性鉴别诊断中的应用价值。方法:回顾性分析87例卵巢实性病灶的临床及影像资料,患者均行卵巢MRI常规平扫、DWI、DKI检查,分别获取ADC值、平均扩散峰度(MK)和平均扩散率(MD),评估DWI、DKI对卵巢良恶性病变的鉴别诊断价值。结果:与卵巢恶性病变相比,卵巢良性病变的ADC值、MD明显升高,MK明显降低(均P<0.05)。ADC、MK、MD联合诊断卵巢良恶性病变的AUC较三者单独及MK联合MD诊断诊断的AUC大。结论:与DWI相比,DKI对卵巢良恶性病变鉴别诊断价值略高;DWI联合DKI可提高对卵巢良恶性病变鉴别诊断效能及卵巢实性病灶检出率。     

MRCP 3D FRFSE系列对良恶性胰胆管梗阻的诊断价值

目的探讨三维快速恢复快速回波脉冲系列磁共振胰胆管水成像(MRCP 3D FRFSE)对良恶性胰胆管梗阻的临床应用价值。方法对106例临床疑有胰胆管梗阻患者行MRCP 3D FRFSE系列检查,2位高年资放射科医师前瞻性分析图像,结果与手术病理或临床随访结果比较。结果106例MRCP检查均一次性成功,肝内外胆管显示率为100%,主胰管显示率为93.4%,其中80例良性梗阻包括肝内外胆管结石66例,乳头炎6例,十二指肠降段憩室炎2例,十二指肠腺瘤样增生1例,慢性胰腺炎5例;26例恶性梗阻包括肝外胆管癌9例,壶腹癌5例,胆囊癌4例,胰头癌8例。MRCP对胰胆管梗阻的定位诊断准确率为100%,在区分良恶性梗阻中,敏感性92.3%,特异性96.3%,准确性95.3%。结论3D FRFSE系列的MRCP是区分良恶性胰胆道梗阻病变较为理想的技术,在临床上有较大的应用价值。     

MRCP对胆系梗阻性疾病的诊断及鉴别诊断研究

目的 探讨胆系梗阻性疾病的MRCP表现及其临床诊断价值.方法 对2002年12月至2004年12月共342例胆系梗阻性疾病进行MRCP检查,所有病例经手术病理或其他影像学和临床资料所证实.使用GE signa MRI/echo speed超导型1.5TMR扫描机,常规行上腹部T1WI和T2WI轴位扫描,MRCP采用单次激发快速自旋回波序列进行冠状位扫描.结果 342例胆系梗阻性疾病的定位诊断正确率为100%,结合常规平扫及其他影像学检查定性诊断正确率可达到92.4%.良性病变（包括胆管结石、胆总管囊肿及胆管炎性狭窄）140例,占所有病例的41%,诊断正确率达95.7%.医源性肝外胆管狭窄21例,占6%,诊断正确率达95.2%.恶性病变（包括胆管癌、胰头癌及壶腹癌）181例,占53%,诊断正确率达89.5%.结论 MRCP作为一种无创性检查手段,结合磁共振平扫和其他临床资料可对良性梗阻性病变及壶腹以上部位的恶性胆道梗阻做出较准确的定性、定位诊断;但对于壶腹周围梗阻性病变的准确诊断有待于进一步研究和改进.     

MRI联合MRCP对肝门部胆管癌的诊断价值

目的探讨MRI与MRCP对肝门胆管癌（HCC）的诊断价值。方法30例手术病理证实的（HCC）患者均经增强前MRI及MRCP，20例还经动态增强MRI。获自上述3种方法的影像表现进行了对比性分析。结果MRCP对肝门部胆管梗阻水平定位准确率达93．3％（28／30），增强前与增强后MRI对病变的定性准确率为83．3％（25，30）。增强前后MRI联合MRCP对病变可切除性的术前评估准确率为80％（24／30）。MRCP显示了所有病例中肝内胆管不同程度扩张，肝门区胆管狭窄、中断或腔内充盈缺损。增强前MRI显示了30例中20例肝门区有稍长T1、稍长T2信号的肿块影。经动态增强MRI20例中17例其肿块表现为延迟期缓慢持续强化，而10例无肿块者表现为管壁增厚、强化，管腔狭窄。结论增强前后MRI可以显示HCC的特征性改变，如联合应用MRCP则有助于提高其定位、定性诊断准确率。     

Diffusion-weighted MR imaging for the differentiation of malignant from benign strictures in the periampullary region

Objectives

To investigate the value of DWI for differentiating malignant from benign strictures in the periampullary region.

Methods

We retrospectively analysed data from 78 patients who had undergone magnetic resonance cholangiopanreatography (MRCP) and diffusion-weighted imaging (DWI), in whom biliary strictures in the periampullary region were suspected. Twenty-two malignant and 56 benign lesions were included. One radiologist compared the signal intensity of malignant and benign periampullary lesions on DWI using b?=?500 and 800 s/mm². The signal intensity of bile was also compared, and an optimal b value was determined for periampullary lesions. Two other radiologists reviewed MRCP alone and combined DWI and MRCP for the possibility of malignant periampullary lesions. Diagnostic accuracy was calculated for each reviewer by receiver operating characteristic (ROC) curve analysis.

Results

Malignant periampullary lesions more frequently appeared hyperintense than benign lesions on DWI using the two b values (P?<?0.001). Bile more frequently appeared hyperintense on DWI using b?=?500 s/mm² (87.2 %) than b?=?800 s/mm² (24.4 %). Therefore, b?=?800 s/mm² was determined as the preferred sequence. Diagnostic accuracy for malignant periampullary lesions improved for both reviewers after adding DWI; from 0.714 to 0.924 (P?=?0.006, for reviewer 1) and from 0.714 to 0.919 (P?=?0.007, reviewer 2).

Conclusions

Combined DWI with MRCP can improve the diagnostic accuracy for differentiating malignant from benign strictures in the periampullary region.

Key Points

? Diffusion-weighted magnetic resonance imaging provides yet more information about hepatobiliary structures. ? Diffusion-weighted imaging (DWI) has now been applied to the biliary tree. ? Most periampullary carcinomas appear hyperintense on high b value DWI. ? DWI can help differentiate between malignant and benign periampullary lesions.     

The added value of diffusion-weighted MR imaging to MR cholangiopancreatography in differentiating malignant from benign extrahepatic biliary strictures

Purpose

To investigate the added value of diffusion-weighted imaging (DWI) to magnetic resonance cholangiopancreatography (MRCP) in differentiating benign from malignant extrahepatic biliary strictures.

Methods

Magnetic resonance examination including, T2-weighted imaging, MRCP and DWI using different b-values (0,500,800 s/mm²) were performed in 38 patients with suspicious extrahepatic biliary strictures. Apparent diffusion coefficient (ADC) value was calculated. The signal intensity of the lesions on DWI using b = 500 and 800 s/mm² was examined. Analysis of the DWI and MRCP images for the cause of the extrahepatic biliary stricutre was performed. Patients were further confirmed by histopathological diagnosis and follow up. Sensitivity, specificity, accuracy, positive predictive and negative predictive values were calculated for both the MRCP images and DWI.

Results

Of the 38 cases, 23 cases had malignant extrahepatic biliary strictures and 15 had benign strictures. DWI detected 21 out of the 23 malignant biliary strictures and 14 out of 15 benign biliary strictures. Malignant strictures more frequently appeared hyperintense than benign strictures on DWI using b-values of 500 and 800 s/mm². There was a significant difference in sensitivity (91.3% vs. 73%), specificity (93.3% vs. 64.7%), accuracy (92.1% vs. 73.6%), positive predictive value (95.4% vs. 81%), and negative predictive value (87.5% vs. 64.7%) between DWI and MRCP in differentiating biliary strictures.

Conclusion

Combined evaluation using DWI added to MRCP improves the differentiation of malignant from benign extrahepatic biliary strictures.     

MRI combined with MR cholangiopancreatography versus helical CT in the evaluation of patients with suspected periampullary tumors: a prospective comparative study

PURPOSE: To establish the diagnostic accuracy of MRI including MR cholangiopancreatography (MRCP) compared with helical CT in the differentiation of malignant and benign lesions in the periampullary region. MATERIAL AND METHODS: Fifty-one patients (27 M, 24 F, mean age 66 years, range 39-86 years) with obstructive jaundice and sonographic evidence of intra- and extrahepatic bile duct dilatation (n=31) or suspicion of periampullary tumor, based on previously performed ultrasound and/or CT examination (n=20), were studied. MRI with MRCP and helical CT were reviewed blindly under standardized conditions. Lesion status (differentiation of malignant versus benign) was rated on a 5-point diagnostic confidence scale. Reference standards for comparison were findings at surgery or laparoscopy and/ or the clinical outcome. The predictive value of imaging findings was determined with multivariate logistic regression analysis. RESULTS: The areas under the receiver operating characteristic curve were 0.96 for MRI with MRCP and 0.81 for CT (P <0.05). Multivariate analysis of eight imaging variables at MRI indicated that a stricture with malignant characteristics at MRCP was the best predictor of malignancy. CONCLUSION: MRI with MRCP was significantly more accurate than CT in differentiating between malignant and benign lesions in patients with suspected periampullary tumors, mainly due to the information obtained on the MRCP images of the biliary and pancreatic duct anatomy.     

A prospective comparison of magnetic resonance cholangiopancreatography with endoscopic retrograde cholangiopancreatography in the evaluation of patients with suspected biliary tract disease.

AIM: To determine the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) compared with direct cholangiography in the detection of biliary tract disease. PATIENTS AND METHODS: MRCP was performed in 100 patients in whom direct cholangiographic correlation (ERCP, n = 98; PTC, n = 9; intraoperative cholangiography, n = 3) was available for comparison. The MRCP examinations were performed using a two-dimensional multi-slice, fast spin echo (FSE) technique and a local surface coil. The diagnoses at direct cholangiography were choledocholithiasis in 30 patients, benign and malignant strictures in 28 patients and normal bile ducts in 42 patients. The nature of the strictures (benign, n = 2; tumour, n = 18; lymphnode recurrence, n = 3; unknown histology, n = 5) was determined by one or more of the following procedures: surgery (n = 8), biopsy (n = 15), cytology (n = 6) and cross-sectional imaging/follow-up findings (n = 3). RESULTS: MRCP diagnosed choledocholithiasis with a sensitivity of 93%, specificity of 99% and accuracy of 97 %. It resulted in two false-negative and one false-positive findings when compared with direct cholangiography. MRCP accurately diagnosed the presence and level of strictures in all patients. The overall sensitivity, specificity and accuracy of MRCP in the detection of bile duct lesions were 97%, 98% and 97%, respectively. CONCLUSION: MRCP has a high diagnostic accuracy when compared with direct cholangiography in the detection of bile duct disease.     

Contrast-enhanced MRI combined with MR cholangiopancreatography for the evaluation of patients with biliary strictures: differentiation of malignant from benign bile duct strictures

PURPOSE: To determine imaging criteria for the combined use of contrast-enhanced (CE)-MRI and MR cholangiopancreatography (MRCP) to differentiate malignant from benign biliary strictures. MATERIALS AND METHODS: A total of 44 patients with biliary stricture who had undergone unenhanced, MRCP, and dynamic MRI were identified from radiological and surgical databases. Two radiologists analyzed MR features for asymmetry, luminal irregularity, abrupt narrowing, outer margin, signal intensity (SI) on T2-weighted (T2W) images, and hyperenhancement relative to liver parenchyma during portal phase. The wall thickness and length of the narrowed segment were measured. MR findings relevant as predictors were identified using a Chi-square or Fisher's exact test and the odds ratio (OR). RESULTS: The presence of hyperenhancement relative to liver parenchyma, length > 12 mm, wall thickness > 3 mm, indistinct outer margin, luminal irregularity, and asymmetry of strictured bile duct were significant factors for malignancy (P < 0.05). Malignant strictures were significantly thicker (5.0 +/- 2.0 mm) and longer (27.0 +/- 13.6 mm) than benign strictures. When any three or more of these six criteria were used in combination, we could identify 100% of malignant strictures and 87.0% of benign strictures. CONCLUSION: The combined use of CE-MRI and MRCP helped to define the criteria for differentiating malignant from benign biliary strictures in our data.     

The role of diffusion-weighted MR imaging for differentiating benign from malignant bile duct strictures

Objectives

To assess the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for differentiating benign from malignant bile duct strictures.

Methods

Twenty-seven patients with a benign stricture and 42 patients with a malignant stricture who had undergone gadoxetic acid-enhanced MRI with DWI were enrolled. Qualitative (signal intensity, dynamic enhancement pattern) and quantitative (wall thickness and length) analyses were performed. Two observers independently reviewed a set of conventional MRI and a combined set of conventional MRI and DWI, and receiver operating characteristic (ROC) curve analysis was assessed.

Results

Benign strictures showed isointensity (18.5–70.4 %) and a similar enhancement pattern (22.2 %) to that of normal bile duct more frequently than malignant strictures (0–40.5 % and 0 %) on conventional MRI (P?<?0.05). Malignant strictures (90.5–92.9 %) showed hypervascularity on arterial and portal venous phase images more frequently than benign strictures (37.0–70.4 %) (P?<?0.01) On DWI, all malignant strictures showed hyperintensity compared with benign cases (70.4 %) (P?<?0.001). Malignant strictures were significantly thicker and longer than benign strictures (P?<?0.001). The diagnostic performance of both observers improved significantly after additional review of DWI.

Conclusions

Adding DWI to conventional MRI is more helpful for differentiating benign from malignant bile duct strictures than conventional MRI alone.

Key points

? Accurate diagnosis and exclusion of benign strictures of bile duct are important. ? Diffusion-weighted MRI helps to distinguish benign from malignant bile duct strictures. ? DWI plus conventional MRI provides superior diagnostic accuracy to conventional MRI alone.     

Magnetic resonance imaging including magnetic resonance cholangiopancreatography for tumor localization and therapy planning in malignant hilar obstructions

PURPOSE: To assess image quality and overall accuracy of magnetic resonance imaging (MRI), including two magnetic cholangiopancreatography (MRCP) techniques, for the diagnostics and preoperative work-up of malignant hilar obstructions. MATERIAL AND METHODS: Thirty-one patients with malignant hilar obstructions (hilar cholangiocarcinoma, n=30; hepatocellular carcinoma, n=1) received MRCP by two techniques (single-shot thick-slab and multisection thin-slice MRCP) and unenhanced and contrast material-enhanced MRI. MR assessment included the evaluation of image quality and visualization of bile ducts (5-point scale), and the classification of tumor status. MR results were subsequently correlated with the results from surgery and pathology. RESULTS: The maximum intensity projections of multisection thin-slice MRCP had significantly more artifacts compared to MRCP in the single-shot thick-slab technique, and overall image quality of single-shot thick-slab MRCP was rated significantly superior compared to multisection thin-slice MRCP (4.4 +/- 0.7 and 4.1 +/- 0.9, respectively). Moreover, ductal visualization of different parts of the biliary system was rated superior with single-shot thick-slab MRCP. In contrast, the original data from multisection thin slice MRCP facilitated visualization of periductal lesions and adjacent structures. Overall MR accuracy for the assessment of tumor status, periductal infiltration, and lymph node metastases was 90%, 87%, and 66%, respectively. CONCLUSION: For evaluation of malignant hilar obstructions, MRCP by the single-shot thick-slab technique had superior image quality and fewer artifacts; in contrast, besides sole biliary visualization, multisection MRCP depicted complementary adjacent parenchymal and periductal structures. We therefore recommend MRI, with a combination of both MRCP techniques, for the diagnostic work-up and therapy planning of malignant hilar obstructions.     

高位胆道梗阻的CT与MRI、MRCP诊断价值

目的　探讨CT、MRI和MRCP对高位胆道梗阻的临床诊断价值。方法　对 12例高位梗阻 (恶性 11例 ,良性 1例 )进行了常规MRI、2DFSE序列MRCP检查 ,其中 10例恶性病变进行了CT检查 (平扫 7例 ,增强 3例 )。结果　CT、MRI和MRCP对高位梗阻定位诊断准确率分别为 90 %、92 %和 10 0 % ,定性诊断准确率分别为 80 %、83%和 6 7% ,MRI +MRCP定性诊断准确率提高到 92 %。10例恶性梗阻CT检查显示肿物 5例 ,胆总管环形增厚 3例。 12例MRI扫描显示肿物 8例 ,肝内转移 2例。MRCP显示梗阻近端形态较为特征 ,截断状以肝癌多见 ,锥状以胆管癌和转移癌多见 ,漏斗状见于良性病变。MRCP显示多发狭窄的长度和范围。结论　CT和MRI对高位梗阻具有同样重要的定性诊断价值。MRCP确定病变部位和范围具有独特的价值。MRI和MRCP结合可提高定位和定性诊断正确率