口服静脉用钆喷替酸葡甲胺对MR胰胆管成像质量影响的研究

目的 选择出静脉用钆喷替酸葡甲胺(Gd-DTPA)作为MR胰胆管成像(MRCP)口服胃肠道阴性对比剂的最佳浓度及容量;评价口服Gd-DTPA对比剂在抑制胃肠道高信号、改善MRCP图像质量中的作用.方法 (1)体外实验:对不同浓度Gd-DTPA稀释液及温开水空白对照组行T1WI、T2WI、二维单层快速自旋回波(FSE)序列及三维半傅立叶单次激发快速自旋回波(HASTE)序列扫描,测量不同成像序列上的信号强度并计算增强率,选择出最佳浓度;(2)临床实验:分别配制不同容量的最佳浓度Gd-DTPA稀释液作为MRCP口服胃肠道阴性对比剂,选择出最佳容量;以最佳浓度和容量Gd-DTPA对比剂对24例临床疑有胰胆管病变的患者行口服前及口服后5～10、10～15 minMRCP扫描,分析图像质量.统计方法采用计算机软件包SPSS 10.0版,对实验结果进行方差分析.结果 T1WI上对照组均为低信号,Gd-DTPA浓度≤0.01 mol/L时为完全高信号;T2WI上对照组为明亮高信号,Gd-DTPA浓度≥0.015 mol/L为完全低信号;2D FSE单层MRCP图像上对照组为明亮高信号,Gd-DTPA浓度在0.0025～0.0300 mol/L之间均为低信号;3D HASTE MRCP图像上对照组为明亮高信号,Gd-DTPA浓度≥0.01 mol/L时为完全低信号;容量≥100 ml浓度为0.01 mol/L的Gd-DTPA对比剂对胃及十二指肠内液体高信号的抑制效果完全;24例患者口服100 ml浓度为0.01 mol/LGd-DTPA对比剂10～15 min后MRCP图像上肝内1、2、3级胆管、肝总管、胆囊、胆总管、胰管头、体、尾的平均等级分数(分别为3.63、3.46、3.08、3.71、3.87、3.88、3.79、3.71、3.50)略高于5～10 min的图像(分别为3.54、3.46、3.00、3.79、3.96、3.87、3.71、3.67、3.54),差异无统计学意义(P值均>0.05),而口服对比剂后肝内3级胆管、胆总管、胰管的等级分数明显高于口服对比剂前(分别为2.79、3.71、3.50、3.42、3.25),差异有统计学意义(F值分别为4.36、4.75、7.86、8.05、7.55,P值均<0.05).结论 100 ml浓度0.01 mol/L的Gd-DTPA对比剂能使胃及十二指肠内潴留液高信号抑制完全,可作为MRCP理想的胃肠道阴性对比剂;口服对比剂后5～10 min行MRCP扫描,图像质量效果最佳.     

十二指肠乳头旁憩室伴胆胰疾病CT及MRI诊断

目的:探讨十二指肠乳头旁憩室伴胆胰疾病的CT和MRI诊断价值。方法:回顾性分析25例经临床随访证实的十二指肠乳头旁憩室伴胆胰疾病的CT和MRI表现,其中21例行CT平扫及增强,9例行MRI平扫、增强以及MRCP。结果:十二指肠乳头旁憩室CT及MRI表现壶腹周围含液气囊性病灶。MRCP表现为十二指肠内侧间壶腹部突出高信号囊性病灶。25例患者中合并胆胰病变CT和/或MRI表现为胆总管及肝内胆管结石13例,胆管扩张及壁增厚强化8例,胰腺肿胀3例,胰周脂肪层模糊4例及渗出2例,肾前筋膜增厚5例,胰管串珠样扩张2例。结论:CT及MR能显示十二指肠乳头旁憩室同时显示胆胰疾病引起胆管及胰腺形态学改变,有助于十二指肠乳头旁憩室伴胆胰疾病诊断。     

胃肠道阴性对比剂在磁共振胰胆管成像中的应用研究

目的　研究胃肠道阴性对比剂在改善磁共振胰胆管成像 (MRCP)质量的应用。方法　体外实验 :将马根维显 (Gd -DTPA)和欧乃影注射液分别用温开水稀释为不同浓度制剂盛入 10ml注射器内 ,以温开水作空白对照 ,然后行MRCP扫描 ,以获取对比剂最佳稀释倍数。临床实验 :对 3 9例临床疑胰胆管系统疾病申请MRCP检查患者行口服稀释 3 0 0倍马根维显溶液前后常规腹部MR和MRCP检查 ,扫描参数及定位完全相同。结果　体外实验 :稀释 3 0 0倍的马根维显溶液和稀释 2 0 0倍的欧乃影溶液为最佳浓度。临床实验 :所有病例口服稀释 3 0 0倍的马根维显溶液后 ,胃与十二指肠内的液体高信号被明显抑制 ,MRCP胆管显示效果对比在服对比剂前后具有显著性意义 (P <0 .0 5 )。结论　口服稀释 3 0 0倍的马根维显溶液作为胃肠道阴性对比剂可有效地改善MRCP图像的质量。     

十二指肠憩室的螺旋CT诊断

目的:分析十二指肠憩室的螺旋CT表现,探讨螺旋CT对该病的诊断价值.方法:分析25例(27个十二指肠憩室)患者十二指肠憩室及其并发症的螺旋CT表现,所有病例均经胃十二指肠造影检查确诊.结果:27个憩室中1个憩室小于1.0 cm,其余26个憩室均大于1.0 cm,其中5例大于2.0 cm,1例超过5.0 cm.憩室表现为胰头右后方圆形或半圆形含气囊袋影,可有液平;服用阳性对比剂者均能见阳性对比剂进入憩室.部分憩室内可见食物残渣影.憩室与胰头交界部边界锐利,合并十二指肠憩室炎者,平扫边缘模糊.结论:上腹部螺旋CT扫描应用广泛,虽对十二指肠憩室的检出率不高,但对巨大憩室及并发症的发现有一定意义.     

口服钆喷替酸葡甲胺溶液行MR胰胆管成像的初步临床应用

目的　应用口服钆喷替酸葡甲胺 (Gd DTPTA)溶液作为胃肠道阴性对比剂 ,以降低胃肠道背景高信号 ,提高磁共振胰胆管成像 (MRCP)的图像质量。方法　用 5 0ml药瓶将Gd DTPA溶液稀释成不同浓度 (分别稀释为 5倍、10倍、15倍、2 0倍 ) ,并设空白对照组 ,行常规及MRCP扫描 ,以选择最佳的对比剂浓度。对 15例疑有胰胆管系统疾病的病人行口服对比剂前后MRCP检查 ,对比剂为稀释 5倍的Gd DTPA溶液 ( 1 488g/L) 2 5 0ml,磁场强度为 1 5T。MRCP成像方法有二维单层快速自旋回波 (FSE)序列及半傅立叶单次激发快速自旋回波 (HASTE)序列。结果　实验部分结果表明稀释 5倍的Gd DTPA溶液T2 WI信号降低最明显 ,达 5 9 3 % ,HASTE序列信号强度降低 82 45 % ,单层MRCP时所有稀释倍数液体信号强度均下降达 90 %以上。所有病例口服对比剂后MRCP扫描胃及十二指肠内液体高信号均较前有明显下降 ,图像质量明显提高 ,以单层MRCP序列胃肠道液体高信号抑制最明显。口服Gd DTPA溶液前后 ,胆总管、胰管及胆囊结构的显示程度等级评分差异有显著性意义 (P <0 0 5 )。结论　稀释 5倍的口服Gd DTPA溶液是一种安全有效地降低胃肠道液体高信号强度、改善MRCP图像质量的胃肠道阴性对比剂     

十二指肠憩室的MRCP诊断和临床意义

目的总结十二指肠憩室的MRI和磁共振胆胰管成像(MRCP)表现,探讨十二指肠乳头旁憩室的临床意义。资料与方法回顾性研究65例MRI或MRCP诊断十二指肠憩室的病例,其中经内镜、消化道造影、胆管造影证实54例,总结憩室的发生部位、大小和信号特征,以及胆管和胰腺伴发征象。结果 54例十二指肠憩室共发现憩室58个。憩室最大径为(17.4±8.3)mm(5～36mm)。5个(8.6%)憩室内含气未见液性成分,30个(51.7%)憩室内含气液平面,23个(39.7%)憩室内为纯液体未见气体成分。49例乳头旁憩室中合并有胆总管扩张39例(79.6%),合并胆总管结石23例(46.9%),合并胆囊结石或胆囊炎或因胆囊病变行胆囊切除手术共38例(77.6%),伴发急性胰腺炎4例(8.2%)。伴发胆管疾病的憩室最大径与无伴发病变的憩室最大径无显著性差异(P>0.05)。结论 MRI和MRCP对十二指肠憩室具有较高的诊断准确性,对于临床治疗有重要指导意义。     

胃肠道阴性对比剂在磁共振胰胆管成像中的应用

目的：评价马根维显（Gd—DTPA）溶液作为胃肠道阴性对比剂对改善磁共振胰胆管成像（MRCP）质量的价值。方法：对30例疑有胰、胆管系统疾病的患者口服对比剂前后分别行常规腹部MR和MRCP检查,采用相同的扫描参数及定位。结果：所有病例口服对比剂后MRCP扫描,胃及十二指肠内液体高信号均较前有明显下降,图像质量明显提高。口服稀释的Gd—DTPA溶液前后,MRCP检查胆总管、胰管及胆囊结构的显示效果具有显著性意义（P〈0．05）。结论：口服稀释的Gd—DTPA溶液是一种安全有效降低胃肠道液体高信号强度、改善MRCP图像质量的方法。     

口服超顺磁性氧化铁在MRCP中的应用

目的：研究超顺磁性氧化铁(SPIO)作为胃肠道阴性对比剂在改善磁共根胰胆管成像(MRCP)质量的应用。方法：30例受检者口服2mmol/Fe／1的SPIO液100m1后进行TSE MRCP检查，采用西门子1．5T MRI扫描机，服药前后常规行单层和多层扫描，原始图像经工作站处理后，采用最大信号强度投影技术重建获得新图像。结果：口服SPIO溶液可以完全抑制胃及十二指肠内液体信号，排除其干扰，使MRCP时胰胆管显影更加清晰。结论：口服SPIO，行MRCP检查，能抑制胃肠道内液体信号，使胰胆管显影更加清晰，特别是在TSEMRCP成像时效果更佳。     

口服枸橼酸铁铵对MRCP的影响

目的: 探讨口服枸橼酸铁铵前后MRCP的临床应用价值.材料和方法: 对43例可疑胰胆管病变者行常规MRI及口服枸橼酸铁铵前后MRCP,并根据术后病理诊断,对照研究口服枸橼酸铁铵前后MRCP的诊断准确率.结果: 口服对比剂后图像质量明显改善;常规MRI,综合口服对比剂后前后MRCP定位、定性诊断的准确率明显提高,分别达到100%及95.4%.结论: 口服枸橼酸铁铵后能有效抑制胃、十二指肠内液体高信号,明显改善胰胆管的显像效果,综合口服对比剂前后MRCP对胆胰系统病变具有重要的临床应用价值.     

CT对壶腹旁憩室综合征诊断价值的探讨

目的探讨壶腹旁憩室综合征(Periampullary diverticula syndrome,PADS)的CT表现、诊断价值及分型。方法回顾性分析经内镜或手术证实的22例PADS患者的CT表现,所有患者均行螺旋CT扫描,并提出本病的CT分型。结果22例患者中,共22个憩室。表现为十二指肠降段内侧囊状含气影者13例,含气液平面7例,表现为液性囊状影2例。合并胆管结石11例(其中4例合并胆囊结石),胆囊结石5例,仅表现为肝外胆管轻度扩张4例,胆源性胰腺炎1例,胆管细胞癌1例。结论CT能清楚显示憩室及其胆胰系统并发症,是诊断PADS有效的影像检查方法。     

Magnetic resonance cholangiopancreatography with GRASE sequence at 3.0T: does it improve image quality and acquisition time as compared with 3D TSE?

Objectives

The current study evaluated the clinical usefulness of the gradient and spin-echo (GRASE) sequence with single breath-hold in 3.0 T magnetic resonance cholangiopancreatography (MRCP). We compared the acquisition time and image quality between GRASE and breath navigator-triggered 3D turbo spin echo (3D TSE).

Methods

We examined 54 consecutive patients who underwent MRCP with GRASE and 3D TSE. We compared the image acquisition time and contrast-to-noise ratio (CNR) between the common bile duct (CBD) and liver. Overall image quality, blurring, motion artifacts and CBD visibility were scored on a 4-point scale by two radiologists. Paired t-tests were used to compare the variables.

Results

The mean image acquisition time was 95 % shorter with the GRASE than with 3D TSE (GRASE: 20 s; 3D TSE: 6 min 27 s). The CNR of GRASE was significantly higher than that of 3D TSE (GRASE: 25.4 ± 13.9 vs. 3D TSE: 18.2 ± 9.6, p < 0.01). All qualitative scores for GRASE were significantly better than those for 3D TSE.

Conclusions

3.0 T MRCP with GRASE sequence with single breath-hold significantly improved the CNR of CBD with a 95 % shorter acquisition time compared with conventional 3D MRCP with 3D TSE.

Key Points

? MRCP acquisition time was 95% shorter with GRASE than with 3D TSE.? Overall image quality of GRASE was significantly better than 3D TSE.? Pancreaticobiliary tree visibility with GRASE was better than that with 3D TSE.

     

同层动态磁共振胰胆管成像的临床研究

目的 :利用动态磁共振胰胆管成像 (MRCP)分别评价Oddi括约肌功能及口服果汁对改善胰管显示方面的作用。方法 :将 3 8例经临床或手术病理证实有胰胆管系统疾病的患者 ,分成三组 :A组 (n =15 )为有壶腹部周围的梗阻性病变伴胆道扩张 ;B组 (n =13 )为有壶腹部以上的梗阻性病变伴胆道扩张 ;C组 (n =10 )为未见明显梗阻性病变但有胆道扩张。各组分别摄取动态MRCP图像并观察括约肌舒张情况 ;19例正常志愿者 ,口服果汁 (Orange lemonjuice ,OLJ)前及口服果汁后 15、3 0、45、60、75、90min分别摄取动态MRP图像。结果 :3 8例患者MRCP图像上 ,胆总管远端出现乳头状 ,逐渐狭窄 ,平头状及倒杯口状 4种改变 ,其中倒杯口状改变仅出现于A组 ,与其它两组间差异有显著性意义 (P <0 .0 5 ) ;乳头状、逐渐狭窄及平头状改变 ,各组间差异无显著性意义。动态MRCP可反映括约肌段舒张频次 ,其在A组与其它两组间差异有显著性意义 (P <0 .0 5 )。正常人口服果汁后MRCP成像显示胰管管径增粗 ,管腔信号强度升高 ,体、尾部胰管的显示率提高。结论 :动态MRCP能很好地评价Oddi括约肌功能 ,提高对壶腹部病变的诊断准确性 ;果汁能促进胰腺外分泌 ,改善胰管显示。     

Image quality and focal lesion detection on T2-weighted MR imaging of the liver: comparison of two high-resolution free-breathing imaging techniques with two breath-hold imaging techniques

PURPOSE: To evaluate image quality and accuracy for the detection of focal hepatic lesions depicted on T2-weighted images obtained with two high-resolution free-breathing techniques (navigator-triggered turbo spin-echo [TSE] and respiratory-triggered TSE) and two standard-resolution breath-hold techniques (breath-hold TSE with restore pulse and half-Fourier acquisition single-shot TSE [HASTE]). MATERIALS AND METHODS: Our institutional review board approved this study, and written informed consent was obtained from all patients. Two readers independently reviewed 200 T2-weighted imaging sets obtained with four sequences in 50 patients. Both readers identified all focal lesions in session 1 and only solid lesions in session 2. The readers' confidence was graded using a scale of 1-4 (1 or= 95%). The diagnostic accuracies of the four MR sequences were evaluated using the free-response receiver operating characteristic (ROC) method. Region-of-interest (ROI) measurements were performed for the mean signal intensity (SI) in the liver, spleen, hepatic lesions, and background noise. RESULTS: The accuracy of navigator-triggered TSE and respiratory-triggered TSE was superior to that of breath-hold TSE with restore pulse and HASTE for the detection of all focal or solid hepatic lesions. The mean lesion-to-liver contrast-to-noise ratio (CNR) of solid lesions in navigator-triggered (P < 0.001) and respiratory-triggered TSE (P < 0.005) was significantly higher than that in HASTE. CONCLUSION: High-resolution, free-breathing, T2-weighted MRI techniques can significantly improve the detectability of focal hepatic lesions and provide higher lesion-to-liver contrast of solid lesions compared to breath-hold techniques.     

A comparison of MR cholangiopancreatography at 1.5 and 3.0 Tesla

Clinical MR systems operating at 3.0 Tesla have the potential to significantly improve spatial resolution due to the boost in intrinsic signal to noise ratio. However, body imaging at these field strengths presents a number of technical challenges. We performed a prospective pilot study in which 10 patients underwent an MR cholangiopancreatography (MRCP) examination consecutively on 1.5 and 3.0 Tesla systems (both Philips Intera). An axial half Fourier segmented turbo spin echo (HASTE) sequence and a coronal thick-slab 2D turbo-spin echo (TSE) sequence were compared on both systems. A reader measured the signal intensity (SI) ratios of common bile duct (CBD): liver, and CBD: fat on HASTE images and CBD: liver on the TSE images. A second reader performed a qualitative analysis of the intrahepatic and extrahepatic biliary anatomy. Quantitative data was compared using the paired t-test and qualitative data with the paired Wilcoxon signed rank test with p < 0.05. The quantitative analysis of the HASTE sequences showed a slightly higher signal intensity ratio (CBD:liver) at 3.0 Tesla compared with 1.5 Tesla (8.1 vs 5.6, p = 0.002). No significant difference was found between the SI ratios of (CBD:fat) on HASTE images or (CBD:liver) on TSE images. The qualitative analysis showed superior image quality of 3.0 Tesla over 1.5 Tesla images on both HASTE (31 vs 25, p = 0.032), and TSE sequences (34 vs 28, p = 0.043). This pilot study shows that MRCP is feasible at 3.0 Tesla with some improvement in image quality and signal characteristics. Further development may be achieved with sequence optimization and improved coil design.     

Imaging of inflammatory lesions at 3.0 Tesla in patients with clinically isolated syndromes suggestive of multiple sclerosis: a comparison of fluid-attenuated inversion recovery with T2 turbo spin-echo

The aims of this study were to determine and compare the sensitivity of T2 turbo spin-echo (T2 TSE) and fluid-attenuated inversion recovery (FLAIR) sequences at 3.0 T in the detection of inflammatory lesions in patients with clinically isolated syndromes suggestive of multiple sclerosis. Forty-nine patients were examined with a 3.0 T MRI system using 5 mm axial sections of T2 TSE (2:19 min), FLAIR (4:00 min) and pre- and postcontrast T1 spin-echo sequences (3:37 min). Brain lesions were counted and categorized according to their anatomic location. Patients were classified according to Barkhof MRI criteria for FLAIR and T2 TSE sequences. The FLAIR sequence detected more lesions in every anatomic region except for the infratentorial region. The higher sensitivity was significant for the total number of lesions (p<0.01), the juxtacortical (p<0.01), and the periventricular (p=0.01) region. A 9% increase of infratentorial lesions using the T2 TSE sequence was not significant. The higher sensitivity using the FLAIR sequence resulted in one additional MRI criterion in nine patients, whereas the better detection of infratentorial lesions using the T2 TSE sequence resulted in additional MRI criteria in three patients. In conclusion, FLAIR provides the highest sensitivity when compared with the T2 TSE, although T2 TSE still has a diagnostic relevance in terms of MRI criteria classification.     

磁共振胰胆管造影诊断胆管系统结石

目的：评价磁共振胰胆管造影在胆管系统结石中的诊断价值。材料和方法：对１００例胆管系统结石的患者进行了ＭＲＣＰ检查,采用不屏气快速自旋回波（ＦＳＥ）序列重Ｔ２加权成像,并用呼吸触发、脂肪抑制和最大信号强度投影（ＭＩＰ）的三维重建方法。对ＭＲＣＰ的诊断结果与手术或临床作了对照分析。结果：本组病例均获得了诊断质量的ＭＲＣＰ图像;１００例胆道结石的患者共有１５８处结石：肝内胆管结石２６例次,胆囊结石５６例次,总胆管结石７３例次和总肝管结石３例次。胆管系统结石的主要ＭＲＣＰ表现为：圆形或卵圆形信号缺失（充盈缺损）;倒杯口征;靶征;铸型样结石。ＭＲＣＰ结合原始图像对胆管系统结石诊断总检出率为９０％,而ＭＲＣＰ对胆管系统结石诊断部检出率为８２％两者比较（Ｐ〈０．０５）。结论：ＭＲＣＰ结合原始图像对胆管系统结石的诊断有较高的准     

Value of MRCP using oral Gd-DTPA as negative contrast materials in diagnosis of atypical juxtapapillary duodenal diverticulum

ObjectiveTo investigate value of magnetic resonance cholangiopancreatography (MRCP) using oral diluted gadolinium (Gd)-diethylenetriamine penta-acetic acid (DTPA) as negative contrast materials in diagnosis of juxtapapillary duodenal diverticulum with atypical imaging features.MethodsNineteen patients with juxtapapillary duodenal diverticula of which imaging findings were atypical underwent MRCP using oral diluted Gd-DTPA as negative contrast materials after conventional MRCP without any oral contrast materials.ResultsTwenty diverticula were revealed in the 19 patients. At conventional MRCP, the diverticula appeared as rounded lesion with high signal intensity. After oral administration of diluted Gd-DTPA, they disappeared at MRCP. These entities were diagnosed as duodenal diverticula for they communicate with duodenal lumen.ConclusionMRCP using oral Gd-DTPA as negative contrast materials can be helpful in obtaining definitive diagnosis of those juxtapapillary duodenal diverticula without typical imaging features.     

Improving the detectability of focal liver lesions on T2‐weighted MR images: Ultrafast breath‐hold or respiratory‐triggered thin‐section MRI?

The purpose of this study was to determine whether a respiratory-triggered (RT) T2-weighted turbo spin-echo (TSE) sequence with thin section can improve the detectability of focal liver lesions compared to a breath-hold (BH) T2-weighted TSE sequence. In 25 patients an RT TSE with 8-mm sections (8-TSE RT) and 5-mm sections (5-TSE RT) and a BH TSE sequence with 8-mm sections (8-TSE BH) were performed. Forty-one focal liver lesions (mean: 1.8 +/- 1.2 cm; 14 lesions < or =1 cm; 27 lesions >1 cm) were evaluated. The 5-TSE RT was significantly better in lesion detection compared to the 8-TSE BH sequence for all sizes of lesions (40/41 vs. 33/41; P = 0.014). For lesions >1 cm no relevant differences in the detection rate of the sequences were found (8-TSE RT, 26/27; 5-TSE RT, 26/27; 8-TSE BH, 25/27), for lesions < or =1 cm the 5-TSE RT provided significantly better sensitivity than the 8-TSE BH (14/14 vs. 8/14, P = 0.015). The results of this study suggest that lesion detection could be significantly improved by using an RT TSE sequence with thin sections compared with a BH TSE sequence.     

肝外胆管梗阻的磁共振胆胰管造影诊断

目的 评价磁共振胆胰管造影（ＭＲＣＰ）对肝外胆管梗阻性疾病的临床诊断价值。方法 对５４例肝外胆管梗阻性疾病（肝外胆管结石３０例,恶性胆管梗阻２４例）进行ＭＲＣＰ检查,并与临床诊断或手术和病理结果对照分析。ＭＲＣＰ采用不屏气快速自旋回波（ＴＳＥ）序列重工Ｔ２ＷＩ扫描,结合呼吸触发及脂护抑制技术,原始图像以最大信号强度投影（ＭＩＰ）法进行三维重建。结果 全部５４例ＭＲＣＰ检查均一次成功,５２例胆胰管显     

磁共振胆胰管成像(MRCP)中成像方法的选择

目的：研究磁共振胆胰管成像（MRCP）时,应用胃肠道阴性对比剂（葡萄糖酸亚铁糖浆）后,不同成像方法的优,缺点。方法：50例受检者口服12％ V／V葡萄糖酸亚铁糖浆后进行MRCP检查;采用GE1．5T MRI扫描机,常规薄层MIP成像及厚层单次激发成像（Single-Shot),薄层单次激发MIP成像。结果：随着TE时间的延长,葡萄糖酸亚铁糖浆对胃肠道液体信号的抑制作用增强,使MRCP时胆胰管显影更加清晰,尤其在单次激发成像时,结合MIP与厚层单次激发图像可以得到更多信息。结论：口服胃肠道4阴性对比剂后行MRCP检查,能够抑制胃肠道内液体信号,使胆胰管显影更加清晰,特别是在单次激发成像时。