磁共振不同脉冲序列成像对慢性胰腺炎与胰腺癌的诊断价值

慢性胰腺炎及胰腺癌的诊断及鉴别诊断一直是临床工作中的难点,本文回顾了磁共振技术在慢性胰腺炎与胰腺癌鉴别诊断方面的应用进展,描述了不同磁共振脉冲序列中正常胰腺组织的信号特点,以及慢性胰腺炎和胰腺癌的不同表现,比较了ERCP、CT、MRCP、MRI检查诊断慢性胰腺炎及胰腺癌的优势与不足。     

胰腺磁共振扩散加权成像的临床应用进展

慢性胰腺炎(CP)和胰腺癌是临床常见病,发病率逐年增高.最近研究表明,胰腺DWI在CP早期诊断与外分泌功能评价、胰腺肿瘤性(样)病变的鉴别诊断具有重要的应用价值.本文对DWI的理论基础、胰腺DWI技术、特别是其在胰腺癌和CP诊断中的应用进展进行综述.     

不同b值磁共振扩散加权成像鉴别诊断胰腺癌与慢性肿块型胰腺炎

目的 分析不同b值下胰腺癌、慢性肿块型胰腺炎与正常胰腺组织ADC值及其差值(DADC值)变化情况,探讨用于鉴别胰腺癌、慢性肿块型胰腺炎的最适b值.方法 对15例胰腺癌(Ⅰ组)、4例慢性肿块型胰腺炎患者(Ⅱ组)及15名胰腺正常的志愿者(Ⅲ组)行磁共振扩散加权成像(DWI),b值分别为333、667、1000 s/mm2.测量各b值下癌区、慢性炎症区和正常胰腺区的ADC值,并对不同b值时三种组织ADC值及不同组织间DADC值的变化进行分析.结果 相同b值时胰腺癌区ADC值低于慢性炎症肿块区和正常胰头区.不同b值时各组内ADC值差异均有统计学意义(P<0.05),随b值增大,三组的ADC值均有下降,其中胰腺癌区平均下降率最低(15.66%和5.19%).b=333和667 s/mm2时,胰腺癌区与慢性炎症肿块区、胰腺癌区与正常胰头区的ADC值差异均有统计学意义(P<0.05).不同b值时,胰腺癌区与慢性炎症肿块区、胰腺癌区与正常胰头区两配对组组内的DADC值差异均有统计学意义(P<0.05),且b=333 s/mm2时各配对组组内的DADC值最大.结论 在一定范围内小b值有助于胰腺癌与慢性肿块型胰腺炎的鉴别诊断.     

MR弹性成像评价梗阻型慢性胰腺炎

目的 探讨3.0T MR弹性成像（MRE）诊断梗阻型慢性胰腺炎的价值。方法 对32例疑诊梗阻型慢性胰腺炎且接受胰十二指肠切除术患者（病变组）及32名健康志愿者（正常对照组）行MRE检查,测量胰腺弹性值。评价2名医师间及重复测量胰腺弹性值的一致性;比较两组胰腺弹性值,绘制ROC曲线,评价以胰腺弹性值鉴别梗阻型慢性胰腺炎的诊断效能。结果 2名评估者间及重复测量胰腺弹性值一致性好（ICC均>0.9）;正常对照组及病变组胰腺体部弹性值分别为（1.21±0.11）kPa、（1.51±0.24）kPa,差异有统计学意义（t=-6.077,P<0.001）;MRE弹性值诊断有无、轻度与中重度、轻中度与重度慢性炎症的AUC分别为0.900、0.941和0.960（P均< 0.001）。结论 MRE可测量胰腺弹性值,有助于临床无创性客观评估慢性胰腺炎的严重程度。     

磁共振扩散加权成像对胰腺癌的诊断价值

目的：探讨磁共振扩散加权成像（DWI）对胰腺癌的诊断价值。方法：收集31例胰腺癌（15例合并肝脏转移瘤、21例合并淋巴结转移）、25例正常对照组行磁共振常规扫描和DWI（b值取0、600 s/mm2）,分析比较胰腺癌病灶、剩余胰腺实质区与对照组胰腺DWI信号特点,并测定各组表观扩散系数（ADC）。定量分析比较各组间ADC值有无统计学差异。结果：31例胰腺癌中,27例呈高信号,15例合并肝脏转移瘤及21例合并淋巴结转移均呈高信号,胰腺癌组、剩余胰腺实质区、对照组ADC值分别为（1.57±0.26）×10-3 mm2/s、（1.93±0.49）×10-3 mm2/s、（1.77±0.19）×10-3 mm2/s,胰腺癌组ADC值低于剩余胰腺实质区（t=3.61,P＜0.001）、低于对照组（t=3.21,P＜0.01）,剩余胰腺实质区与对照组比较无统计学差异（t=1.54,P＞0.05）。结论：DWI可清晰显示胰腺癌病灶及肝脏转移、淋巴结转移灶,对胰腺癌诊断及分期具有重要价值。     

磁共振扩散加权成像对急性胰腺炎的早期诊断价值

目的：探讨磁共振扩散加权成像（DWI）及表观扩散系数（Apparent diffusion coefficient,ADC）对于急性胰腺炎的早期诊断价值。方法：对25例急性胰腺炎患者、23例健康志愿者进行常规MR和DWI扫描,采用单次激发自旋回波-回波平面成像（SE-EPI）序列,b值为0、500和0、800s/mm2,所有急性胰腺炎患者均于发病后48h内完成检查。测量胰腺ADC值,比较不同b值下,急性胰腺炎组、志愿者组的ADC值差异。结果：①健康志愿者胰腺DWI呈中等信号,急性胰腺炎患者中17例呈弥漫均匀性高信号,5例呈不均匀高信号,3例呈中等信号。②急性胰腺炎组、志愿者组在b值为0、500s/mm2时,二组的ADC值分别为（1.52±0.287）×10-3、（1.84±0.233）×10-3mm2/s;b值为0、800s/mm2时,二组的ADC值分别为（1.23±0.128）×10-3、（1.64±0.273）×10-3mm2/s。二组的ADC值差异在b值为0、500及0、800s/mm2时,均有统计学意义（P<0.05）。结论：DWI可以显示急性胰腺炎的病灶及范围,结合ADC值测量,对于急性胰腺炎早期诊断有一定意义。     

磁共振成像在胰腺疾病中的应用进展

胰腺疾病的发病率逐年升高,磁共振成像技术在胰腺疾病检查中的优势日趋明显.本文对不同胰腺疾病MRI表现、MRI在诊断和鉴别诊断中的作用及在胰腺疾病临床研究中的应用进展做一综述.     

磁共振扩散加权成像在急性胆源性胰腺炎的应用

目的：探讨DWI表观扩散系数（ADC）值在诊断急性胆源性胰腺炎（ABP）的价值。方法：两病例组分别为13例ABP患者和17例梗阻性黄疸患者,对照组为15例健康志愿者。行胰腺DWI检查,计算不同病例组、对照组之间的ADC值并统计分析其差异。结果：ABP患者的ADC值低于对照组（P＜0.05）,在b值为500、700s/mm2时,梗阻性黄疸组患者ADC值低于对照组、高于ABP患者（P＜0.05）。结论：应用DWI检查可以辅助临床早期诊断ABP,推荐胰腺DWI检查b值使用500s/mm2。     

胰泌素刺激-磁共振胰胆管成像定量分析猫慢性胰腺炎的胰腺外分泌功能

目的 探讨胰泌素刺激-磁共振胰胆管成像(S-MRCP)定量评估猫慢性胰腺炎(CP)胰腺外分泌功能的价值.方法 将32只健康成年猫分为实验组(n=24)及对照组(n=8);实验组剖腹行胰管不全结扎,建立CP模型,对照组仅行无菌开腹,不结扎胰管.对实验组分别于建模后3、5、7周分批行S-MRCP检查,每批次8只;对照组于缝合关腹后立即进行检查.S-MRCP检查完成后对动物胰腺进行病理学分析,根据病理结果将实验组分为3个亚组:CP-Ⅰ(轻度CP)、CP-Ⅱ(中度)、CP-Ⅲ(重度CP).对各组注射胰泌素前、后胃肠道液体量的增加程度(FVID)进行统计学分析.结果 实验组24只中,1 5只建模成功,CP-Ⅰ、CP-Ⅱ、CP-Ⅲ亚组分别为7、5、3只.注射胰泌素5 min及15 min后实验组整体FVID低于对照组(F=9.742、13.543,P均＜0.05).对照组与CP-Ⅱ亚组间、对照组与CP-Ⅲ亚组间及CP-Ⅰ与CP-Ⅲ亚组间差异均有统计学意义(P均＜0.05);其余各组间差异虽无统计学意义(P均＞0.05),但随着胰腺炎程度加重,FVID有逐渐下降趋势.结论 利用S- MRCP可通过测量注射胰泌素前、后胃肠道液体量的变化评价猫CP模型胰腺外分泌功能.     

多种MRI技术联合应用鉴别诊断胰腺癌与慢性胰腺炎

目的　评价联合应用多种MRI技术在鉴别诊断胰腺癌和慢性胰腺炎中的价值。方法　回顾分析 47例胰腺癌与 2 8例慢性胰腺炎的MRI表现。MRI技术包括 :平扫FSFLASHT1WI和TSET2 WI、MR胆胰管成像 (MRCP)及多时相动态增强扫描。测量肿块与正常胰腺信号值 ,计算对比噪声比 (CNR)。结果　平扫FSFLASHT1WI和TSET2 WI对胰头癌的敏感率为 5 9.4% ,对胰体癌为 86.7% ,对慢性胰腺炎为 78.6%。MRCP对胰头癌的敏感率为 90 .6% ,对胰体癌为 6.67% ,对慢性胰腺炎为 82 .1%。多时相动态增强扫描对胰头癌的敏感率为 78.1% ,对胰体癌为 93 .3 % ,对慢性胰腺炎为85 .7%。联合应用多种MRI技术对胰头癌的敏感率为 96.9% ,对胰体癌为 93 .3 % ,对慢性胰腺炎为 92 .9% (P <0 .0 1)。结论　多种MRI技术联合运用 ,是一项对胰腺癌和慢性胰腺炎进行鉴别诊断的准确有效的方法     

Update to pulse sequences for interventional MR imaging

The motivations for developing MR-guided minimally invasive therapy include its excellent soft tissue contrast, tomographic imaging in any direction (as opposed to projection imaging as in fluoroscopy), the absence of ionizing radiation,the abundance of contrast mechanisms (including bright blood pulse sequences that lead to excellent vessel conspicuity without exogenous contrast agent injection), the ability to obtain physiologic information such as perfusion, and an overall excellent safety profile. The main pulse sequences used today for interventional MR imaging are T1/T2-weighted FISP and TrueFISP, T2-weighted turbo spin-echo, and T1-weighted FLASH. The specific clinical question, the underlying pathophysiology,and the procedure to be performed dictate which sequence is used. Each of these sequences has been written to acquire data in conventional rectilinear trajectories, radial k-space paths, or even spirals. In many ways, the questions being researched in interventional MR imaging have been dictated by the primary issues in greatest need of resolution or that most directly facilitate new clinical development. A decade ago, research focused on exploration of new scan strategies for contrast and temporal resolution. Advancements in the last decade have made it possible to acquire and display greater than 10 images per second in realtime with millimeter resolution in all three directions. This temporal and spatial resolution is considered high enough to guide most interventions. With this capability, other research has focused on instrument tracking. The field has gone from the capability to track a single coil and superimpose it on a previously acquired roadmap to systems that follow, adapt, and provide high-resolution images due to the advent of multichannel receiver systems, improved graphics, higher processor speeds, and increases in speed and quantity of memory. Hence, instruments can be reliably identified and tracked and the information can be used to update pulse sequence parameters in real time, thereby opening new opportunities for interventional MR imaging that extend from biopsy and thermal therapy to image-guided vascular and cardiac procedures. Today, we see such issues as RF heating of wires used for device localization and the noise generated by rapid switching of MR gradients being significant obstacles yet to overcome to allow the full strength of MR-guided interventions to be realized clinically. It is anticipated that these topics will emerge as critical concepts in the next decade of interventional MR imaging research.     

不同MRI序列显示乳腺病变的比较

目的比较不同MRI序列显示乳腺病变的价值.方法对79例乳腺癌和68例乳腺良性疾病患者采用自旋回波(SE)序列、快速自旋回波(TSE)序列、脂肪抑制(FS)成像、快速小角度激发(FLASH)序列、静态或动态增强扫描,比较不同MRI序列对乳腺病变的显示检出情况.结果脂肪抑制成像序列对乳腺病变的检出率高于SE序列,SE序列有利于病灶病理解剖关系的显示,MR增强扫描可检出所有乳腺病灶且有助于明确病灶的内部结构、浸润范围及其血供情况.结论 SE、TSE应为乳腺MR检查的常规序列,脂肪抑制成像序列必不可少,MR增强扫描对病灶的定性诊断很有价值,尤其是FLASH动态增强扫描.     

短时翻转恢复序列在皮肌炎、多发性肌炎中的应用价值

目的探讨短时翻转恢复(short-tau inversion recovery,STIR)序列在皮肌炎、多发性肌炎中的应用价值。材料与方法回顾分析我院12例经临床确诊和(或)穿刺活检病理证实的皮肌炎/多发性肌炎患者资料。选择双侧大腿肌肉作为感兴趣区,采用常规T1WI、T2WI及STIR序列进行扫描,观察STIR序列与T1WI、T2WI在病变检出能力上的差异。结果 (1)本组12例患者于MRI上发现双侧大腿有不同程度异常信号表现,其中提示为肌炎11例、肌筋膜炎8例、皮下结缔组织炎9例、肌肉萎缩伴脂肪浸润1例。(2)在STIR序列上,12例患者均被发现双侧大腿有异常信号;T1WI仅发现5例皮下结缔组织炎,1例肌肉萎缩,未发现肌炎、肌筋膜炎;T2WI发现6例肌炎,1例肌肉萎缩及2例皮下结缔组织炎,未发现肌筋膜炎。(3)在STIR序列上,发现有7例患者的双侧大腿后、内侧肌群信号较其他受累肌群信号高,经病理证实该处肌肉损伤程度较重。结论 STIR序列具有高软组织分辨率和高灵敏性,可明显提高软组织炎性病变的检出率,其信号强度可主观反映肌肉的损伤程度,在临床上具有重要应用价值。     

Multidetector row CT and MR imaging in diagnosing hepatocellular carcinoma

It is important to diagnose hepatocellular carcinoma (HCC) correctly and in early stage, because viral hepatitis and liver cirrhosis are often complicated by HCC. Noncontrast and enhanced CT and MRI are very useful to visualize and diagnose HCC objectively. Especially, CT and MR imaging with dynamic study is essential to diagnose HCC, because it is usually hypervascular. Dynamic CT and MR study also improve differential diagnosis in the characterization of the tumor. However, to perform useful dynamic study, it is necessary to use a CT unit which can make a helical scan, or a MR system with fast imaging technique available that can obtain more than 15 slices within a single breath hold. Tissue specific contrast medium, such as superparamagnetic iron oxide that is available only on MRI, is also useful for diagnosis of HCC.     

磁敏感加权成像对帕金森病患者的诊断价值

目的:探讨磁敏感加权成像(SWI)在帕金森病(Parkinson disaese,PD)的诊断及其病情严重程度评估中的临床应用。方法:选取PD患者30例和健康志愿者30例,应用SWI对所有受试者锥体外系多个核团计算相位值,进行统计学分析。结果:PD组黑质致密带、苍白球、壳核相位值均低于健康志愿者组,差异有统计学意义(P0.01)。PD组黑质致密带、苍白球、壳核相位值早期即降低,并随着病情加重,相位值进一步降低,差异有统计学意义(P0.05)。结论:SWI技术对PD的诊断及评估具有重要的临床价值。     

Detection of lymph-node metastases in patients with gastric carcinoma: comparison of three MR imaging pulse sequences

Background: To compare the diagnostic accuracy of magnetic resonance (MR) images obtained with three different pulse sequences for lymph-node metastases in patients with gastric cancer. Methods: T1-weighted spin-echo (SE), breath-hold T2-weighted fast SE, and triphasic gadolinium-enhanced dynamic gradient-recall-echo (GRE) MR images obtained in 16 patients with gastric carcinoma were retrospectively reviewed. Regional lymph nodes were assigned to four different groups, and image review was conducted on a lymph-node group-by-group basis; 64 lymph-node groups were reviewed by two radiologists. Relative sensitivity, specificity, and accuracy were determined based on the findings with definitive surgery and follow-up imaging. Diagnostic accuracy was determined by means of receiver-operating-characteristic (ROC) analysis. Results: Relative sensitivities for lymph-node metastases with T1-weighted SE, breath-hold T2-weighted fast SE, and dynamic GRE images were 61%, 94%, and 59%, respectively. Relative sensitivity with breath-hold T2-weighted fast SE images was significantly greater than that with T1-weighted SE (p < 0.05) and dynamic GRE (p < 0.05) images. Diagnostic accuracy determined by ROC analysis was marginally higher with breath-hold T2-weighted fast SE (area under ROC curve [Az]= 0.87) than with T1-weighted SE (Az = 0.78, p= 0.08) and dynamic GRE (Az = 0.79, p= 0.12) images. Conclusion: Breath-hold T2-weighted fast SE sequence is useful in the detection of regional lymph-node metastases in patients with gastric carcinoma. Received: 11 November 1998/Revision accepted: 7 April 1999     

MR imaging of advanced gastric cancer: comparison of various MR pulse sequences using water and gadopentetate dimeglumine as oral contrast agents

Background: To evaluate clinical usefulness of oral contrast agents (gadopentetate dimeglumine and water) and to assess proper magnetic resonance (MR) imaging in evaluating advanced gastric cancer (AGC) by comparing different MR imaging techniques. Methods: Fifteen patients with AGC were imaged with a 1.0-T MR imager and body-array coil. All patients underwent surgery or laparascopic biopsy. Fast low-angle shot (FLASH), half-Fourier single-shot turbo spin-echo (HASTE), and true fast imaging with steady-state precession time (FISP) images were obtained after ingestion of 900 mL tap water in each patient, followed by postcontrast FLASH images after additional ingestion of gadopentetate dimeglumine (Gd-DTPA). Qualitative analysis including T-staging of AGC and scoring of imaging quality and quantitative analysis were performed prospectively. Results: In image quality and diagnostic accuracy of T-staging, FLASH imaging showed results slightly superior to those of other imaging modalities, and there was no great difference between using water and Gd-DTPA as an oral contrast agent. As for cancer-to-gastric lumen contrast-to-noise ratio (CNR), HASTE and true FISP imaging were superior to FLASH imaging with Gd-DTPA (p < 0.0001). In cancer-to-pancreas CNR, FLASH imaging without Gd-DTPA showed the best result. Conclusions: The use of Gd-DTPA as a positive contrast agent may not be imperative, and T1-weighted FLASH imaging in combination with true FISP imaging with ingestion of tap water can be very useful in evaluating AGC with MR imaging. Received: 29 October 1998/Revision accepted: 27 January 1999