1、慢性胰腺炎及其并发症的慢性胰腺炎及其并发症的MRI表现表现 早期表现包括T1加权脂肪抑制图像上呈低信号，延迟强化或强化程度减低，侧支扩张。晚期表现包括实质萎缩或肿大，假性囊肿，胰管扩张或呈串珠样，导管内常伴钙化。MRI可以早期识别慢性胰腺炎胰腺信号强度的变化，平扫和增强T1加权脂肪抑制图像显示信号变化最佳（图1A，1B，1C，1D）。Fig.1A.24-year-old woman with small pancreatic duct stone causing duct obstruction and segmental pancreatitis.Axial T2-weighted HAST
2、E image shows slightly increased signal intensity of pancreatic tail(arrow)with mild dilatation of pancreatic duct.Axial T1-weighted fat-suppressed spoiled gradient-echo image shows abnormal low signal intensity of pancreatic tail(arrow)while remainder of pancreas has normal bright signal intensity.
3、24岁，女。小胰管结石引起胆道梗阻和节段性胰腺炎。T2WI胰尾信号轻度升高，胰管轻度扩张（箭头）。T1WI显示胰尾异常低信号（箭头），胰腺其余部分信号强度正常，为高信号。Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during arterial phase shows delayed enhancement of pancreatic tail(arrow)relative to normal pancreas due to fibrosis.Patient later devel
4、oped atrophic changes in this area that led to resection of pancreatic tail.Contrast-enhanced CT scan shows punctate high-density focus(arrow)in pancreatic duct representing small intraductal stone.This example illustrates the advantage of CT in showing tiny intraductal stone that was not seen on MR
5、I.It,however,also illustrates the advantage of MRI in showing changes of signal intensity associated with chronic pancreatitis that are not visible on CT.动脉期增强T1WI示因纤维化胰尾较正常胰腺强化延迟（箭头），此处后来呈萎缩性改变，导致实行胰尾切除术。对比增强CT扫描显示胰管内小结石。这个例子说明了CT的优势在于显示微小的管内结石，而在MRI未显示。然而，它也显示出磁共振成像的优点：可显示出慢性胰腺炎信号强度的变化与关系，此在CT上是不可
6、见的。慢性炎症和纤维化减少胰腺的蛋白质含量，使得在T1加权脂肪抑制图像上高信号消失。正常胰腺动脉期均匀明显强化，并快速廓清。相比之下，慢性纤维化并腺体萎缩的胰腺在早动脉期强化程度减低并强化不均匀，延迟图像上强化程度相对升高（图2A，2B，2C）Fig.2A.46-year-old man with history of chronic pancreatitis due to alcohol abuse.Axial T1-weighted fat-suppressed spoiled gradient-echo image shows atrophy of pancreatic parenchy
7、ma and irregular dilatation of main pancreatic duct(arrows),changes suggestive of chronic pancreatitis.Calcifications are not as well seen on MRI as on CT.Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during arterial phase shows diffusely decreased pancreatic enhance
8、ment relative to marked enhancement seen normally.This decreased enhancement relates to fibrosis due to chronic pancreatitis.Dilated pancreatic duct(arrows)is visualized more clearly after contrast administration.46岁，男，因酗酒致慢性胰腺炎。T1WI显示胰腺实质的萎缩和不规则扩张的主胰管（箭头），提示慢性胰腺炎的变化。钙化在MRI和CT上都没有看到。动脉期增强T1WI显示胰腺因慢性
9、炎症引起的纤维化而强化弥漫性降低，而非通常看到的显著增强。胰管扩张（箭头）显示更清。MRCP is highly accurate for identifying pancreas divisum(Fig.6).However,its association with pancreatitis remains controversial.Duct abnormalities such as dilatation,irregularity,and stones and complications of chronic pancreatitis such as pseudocysts are be
10、st depicted by thin-section T2-weighted HASTE or single-shot fast spin-echo and thick-slab T2-weighted half-Fourier RARE MRCP images.MRCP发现胰腺分裂的准确度很高（图6）。然而，它与胰腺炎的关系仍存在争议。胰管异常，如扩张，不规则，结石和并发症如假性囊肿，在薄层T2加权HASTE或MRCP显示最佳。Fig.6.53-year-old woman with history of cholecystectomy who presented with jaundic
11、e,abnormal results on liver function tests,and pancreas divisum.Axial T2-weighted image shows noncommunicating main pancreatic duct(straight arrow)and accessory duct(curved arrow)draining separately into duodenum.图6，53，女。胆囊切除术后，黄疸，肝功能异常，胰腺分裂症。轴位T2WI显示轴向T2加权图像显示，互不沟通的主胰管（直箭头）和配胰管（弯箭头）分别进入十二指肠引流。MRCP
12、is accurate in depicting strictures of the pancreatic duct or biliary tract(Fig.7).In equivocal cases,ductal distention by contrast injection during ERCP may be helpful.The beaded main pancreatic duct with its dilated side branches may have a chain-of-lakes appearance when more extensive(Fig.8).MRCP
13、可准确的描绘胰管或胆管的狭窄（图7）。在模棱两可的情况下，在ERCP过程中导管注射造影剂扩张胰胆管可能会有帮助。当病变广泛时，串珠样主胰管和扩张的侧枝，可能有连锁湖样改变。Fig.7.62-year-old woman with history of chronic pancreatitis and pseudocysts.Coronal T2-weighted thick-slab RARE image shows stricture(straight arrow)of pancreatic duct at level of pancreatic head.Upstream pancreat
14、ic duct is dilated and irregular,and there is mild dilatation of side branches.Note diverticulum(curved arrow)arising from duodenum.图7。62，女。慢性胰腺炎，假性囊肿。冠状T2WI显示胰头水平胰管狭窄（直箭头）。上游胰管不规则扩张，侧枝轻度扩张。注意十二指肠憩室（弯箭头）。Fig.8.69-year-old man with chronic pancreatitis.Axial T2-weighted HASTE image shows irregular di
15、lated main pancreatic duct and side branches giving chain-of-lakes appearance.Note atrophic changes in pancreas and signal-void areas(arrows)related to calcifications from chronic pancreatitis.图8。69岁，男。慢性胰腺炎。轴向T2WI显示不规则扩张的主胰管和侧枝，连锁湖外观。可见胰腺萎缩及无信号钙化区（箭头）。CT is more sensitive than MRI for the detection
16、 of calcifications associated with chronic pancreatitis;however,MRI best depicts intraductal stones and duct obstruction(Figs.9A,9B and 10).Unlike ERCP,MRCP can show the dilated duct upstream from an obstructing stone.Nevertheless,visualizing intraductal stones not surrounded by fluid may be difficu
17、lt on MRI(Fig.1A,1B,1C,1D).对慢性胰腺炎的钙化检测，CT比MRI敏感，然而，MRI显示管内结石和胰胆管阻塞最佳（图9A，9B和10）。不同于ERCP，MRCP能显示上游扩张导管。然而，MRI诊断不被液体包围的导管内结石困难（图1A，1B，1C，1D）。Fig.9A.46-year-old man with history of chronic pancreatitis due to alcohol abuse.Axial contrast-enhanced CT scan shows multiple calcifications in pancreatic head
18、.It is difficult to determine that a stone is in pancreatic duct.Calcifications are seen commonly in chronic alcohol-related pancreatitis,as in this patient.Axial T2-weighted HASTE image shows stone(arrow)in main pancreatic duct delineated by high-signal-intensity fluid.图9A。男，46岁。酗酒史，慢性胰腺炎。轴向增强CT扫描显
19、示胰头多发钙化。从CT很难确定胰管内有无结石。钙化在慢性酒精相关性胰腺炎中很常见，此例即如此。轴向T2WI的显示主胰管内结石（箭头）被高信号液体包绕。Fig.10.45-year-old woman with history of abdominal pain.Coronal T2-weighted HASTE image shows pancreatic duct stone(straight arrow)and gallstone(curved arrow).GB=gallbladder,CBD=common bile duct,PD=pancreatic duct,DUOD=duoden
20、um.图10。45岁，女，腹痛。冠状T2WI的显示胰管内结石（直箭头）和胆结石（弯箭头）。GB=胆囊，CBD=胆总管，PD=的胰管，DUOD=十二指肠。1.Pseudocysts 假性囊肿 2.Vascular 血管相关并发症 3.Biliary 胆管相关并发症 Pseudocysts are encapsulated collections of pancreatic secretions that occur in or around the pancreas.Although most resolve spontaneously,complications such as infecti
21、on,hemorrhage,and gastric or biliary obstruction may occur(Fig.11A,11B).Pseudocysts can be communicating with the main pancreatic duct(Fig.12)or noncommunicating.MRI can depict pseudocysts and can be used to characterize their content and thus to guide drainage.假性囊肿是发生在胰腺内或胰腺周围被包裹的胰腺分泌物。虽然大多数可自发吸收，但
22、也可发生并发症，如感染，出血，胃或胆道梗阻（图11A，11B）。假性囊肿与主胰管可连通（图12）或不连通（图13）。MRI可以描绘假性囊肿并检测内容物成分以指导引流。52-year-old man with history of recurrent pancreatitis.Axial T2-weighted HASTE image shows large thick-walled multiloculated cystic collection located primarily in lesser sac,representing pseudocyst(P).It does not com
23、municate with pancreatic duct.Axial T1-weighted fat-suppressed spoiled gradient-echo image shows high-signal-intensity fluid within pseudocyst,suggestive of complicated pseudocyst(P).Internal consistency of pseudocysts may be altered because of presence of proteinaceous material,hemorrhage,or infect
24、ion,and it may require prompt drainage.52岁，男，复发性胰腺炎。轴向T2WI的显示主要位于小网膜囊的巨大厚壁多房假性囊肿(P)。不与胰管沟通。轴位T1WI显示囊肿内为高信号，提示其为复杂性假性囊肿（P）。因存在蛋白性物质，出血，或感染，假性囊肿内部一致性可被改变，提示需要尽快引流。Fig.12.55-year-old woman with abdominal pain,weight loss,and history of pancreatitis.Axial T2-weighted HASTE image shows high-signal-intens
25、ity pseudocyst(P)in pancreatic head with dilated and irregular pancreatic duct.Pseudocyst can be seen communicating with main pancreatic duct(arrow).图12。55岁，女。腹痛，体重减轻，胰腺炎。轴位T2WI显示胰头部高信号假性囊肿（P）及不规则扩张的胰管。可以看出假性囊肿与主胰管（箭头所示）连通。Arterial pseudoaneurysms,hemorrhage into pseudocysts,arterial bleeding,and sp
26、lenic or portal vein thrombosis are vascular complications of chronic pancreatitis that may be seen on MRI.In patients with chronic splenic vein thrombosis,the vein may not be visualized.(Fig.14A,14B).假性动脉瘤，假性囊肿内出血，出血，脾静脉或门静脉血栓为慢性胰腺炎的血管相关并发症，MRI可检测出。但当有慢性脾静脉血栓时，静脉可能无法显示（图14A，14B）Fig.14A.46-year-old
27、man with history of chronic pancreatitis due to alcohol abuse.Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during venous phase shows chronic occlusion of portal vein with collaterals(arrow):cavernous transformation of portal vein.Fig.B shows collateral vessels(arrow
28、s),which is suggestive of splenic vein occlusion.46岁，男，慢性胰腺炎，酗酒史。静脉期轴向增强T1WI示门静脉慢性闭塞（箭头）呈海绵样变。图B显示侧支循环形成（箭头），提示脾静脉阻塞。The biliary complications of chronic pancreatitis include choledocholithiasis,fistulas,and dilatation of the common bile duct due to inflammatory strictures.The typical appearance of
29、benign strictures on MRCP is gradual tapering with a funnellike narrowed segment(Fig.15).慢性胰腺炎的胆道并发症，包括胆总管结石，瘘管，由于炎性狭窄而致的胆总管扩张。良性狭窄的典型MRCP表现为逐渐变细的漏斗样狭窄（图15）。Fig.15.59-year-old man with history of chronic pancreatitis.MR image was obtained to evaluate biliary tract and complex pseudocysts seen on pri
30、or CT scan(not shown).Coronal T2-weighted thick-slab RARE image shows dilated common bile duct with funnel-shaped narrowing(arrowhead).Pancreatic duct is dilated and contains calculus(arrow)at pancreatic head level.Also seen are multiple pseudocysts(P)extending both superior and inferior to pancreas
31、.GB=gallbladder.男，59岁，明显胰腺炎。行MRI检测以明确CT所示复杂假性囊肿并评价胆道情况。冠状T2WI显示扩张的胆总管、漏斗样狭窄（箭头）。胰管扩张、胰头处可见结石。并可见多发假性囊肿（P）延伸至胰腺前后方。GB=胆囊。Differentiating between an inflammatory mass due to chronic pancreatitis and pancreatic carcinoma on the basis of imaging criteria remains difficult.Decreased T1 signal intensity w
32、ith delayed enhancement after gadolinium administration as well as dilatation and obstruction of the pancreaticobiliary ducts can be seen in both diseases.Irregularity of the pancreatic duct,intraductal or parenchymal calcifications,diffuse pancreatic involvement,and normal or smoothly stenotic panc
33、reatic duct penetrating through the mass(“duct penetrating sign”)favor the diagnosis of chronic pancreatitis over cancer(Fig.16A,16B,16C).In distinction,a smoothly dilated pancreatic duct with an abrupt interruption,dilatation of both biliary and pancreatic ducts(“double-duct sign”),and obliteration
34、 of the perivascular fat planes favor the diagnosis of cancer.鉴别慢性胰腺炎引发的炎性包块和胰腺肿瘤，从影像学上尚属困难。两者均可出现延迟强化和胰胆管的阻塞扩张。不规则的胰管，胰管内或实质内钙化，弥漫性胰腺受累，光滑狭窄的胰管从肿块内穿过（“穿透症”）更支持慢性胰腺炎的诊断（图16A，16B，16C）。相反的，平滑扩张的胰管突然中断，胆管和胰管同时扩张（“双管征”），以及血管周围脂肪间隙消失则支持肿瘤的诊断。Fig.16A.58-year-old woman with breast cancer and chronic pancre
35、atitis related to alcohol abuse.Patient had 50-lb(23-kg)weight loss.ERCP image(not shown)revealed stone in pancreatic duct,which was removed.Fine-needle aspiration was suggestive of adenocarcinoma.Whipple procedure indicated chronic pancreatitis without cancer.Axial T1 fat-suppressed spoiled gradien
36、t-echo image shows low-signal-intensity pancreas due to chronic pancreatitis.Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during arterial phase shows diffusely decreased enhancement of pancreas due to chronic pancreatitis.Note dilated pancreatic duct.图16A。58岁，女，乳腺癌、
37、酗酒相关的慢性胰腺炎。发病以来体重下降23kg。ERCP图像（图中未示出）显示胰管石并去除。细针穿刺提示腺癌。胰十二指肠切除术提示慢性胰腺炎无癌变。轴向T1WI显示因慢性胰腺炎而呈低信号的胰腺。动脉期增强T1WI示胰腺弥漫性强化减低。注意胰管扩张。Fig.16C.Axial T2-weighted HASTE image shows markedly dilated main pancreatic duct(arrow)penetrating through pancreas with chronic inflammatory and fibrotic changes:“duct penetr
38、ating sign.”This finding suggests chronic pancreatitis over adenocarcinoma.图16C。同一病例。轴向T2WI示明显扩张的主胰管（箭头），穿过具有慢性炎症和纤维化的胰腺：“穿透征”。这一征象提示慢性胰腺炎可能性大。MRI may be superior to MDCT for the evaluation of pancreatic adenocarcinoma,especially if the lesion is small and non-contour-deforming.The tumor is best del
39、ineated on unenhanced T1-weighted fat-suppressed images and multiphasic enhanced sequences(Fig.17A,17B,17C,17D).MRI在对胰腺腺癌的诊断上优于MDCT，特别是病变较小且胰腺外形没有异常时。平扫T1WI及多期增强序列上图17A，17B，17C，17D）显示最佳。71-year-old woman with weight loss due to adenocarcinoma of pancreas with associated chronic pancreatitis.Axial co
40、ntrast-enhanced CT scan shows atrophy of pancreatic tail and duct dilatation(arrow)to level of suspected mass,which is difficult to see.Axial T2-weighted HASTE image shows dilatation of pancreatic duct with abrupt termination(arrow)due to tumor.71岁，女。慢性胰腺炎并腺癌。轴向增强CT示胰尾萎缩和胰管扩张（箭头），无法判断是否有肿块。轴向T2WI示由于
41、肿瘤扩张的胰管突然终止（箭头）。Fig.17C.Axial T1-weighted fat-suppressed spoiled gradient-echo image shows low-signal-intensity mass(arrowhead),measuring less than 1 cm.Note atrophy and decreased signal intensity of pancreatic tail(curved arrow)related to associated chronic pancreatitis.Normally high signal intensi
42、ty of pancreatic head(straight arrow)is preserved.Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during late venous phase shows delayed enhancement of tumor(arrowhead).This example shows value of MRI to depict nondeforming pancreatic mass.同一病例，轴向T1WI示低信号肿块（箭头），小于1厘米。注
43、意慢性胰腺炎引起的胰尾信号减低并萎缩（弯箭头）。胰头仍为正常高信号（直箭头）。静脉期轴向增强T1WI示延迟强化的肿瘤（箭头）。这个例子显示MRI在诊断不伴有胰腺外形失常的胰腺肿瘤中的价值。Groove pancreatitis is a type of focal chronic pancreatitis affecting the groove between the head of the pancreas,duodenum,and common bile duct.The predominant MRI finding of groove pancreatitis is a sheetl
44、ike fibrotic mass between the pancreatic head and thickened duodenal wall associated with duodenal stenosis and cystic changes in the duodenal wall(Fig.18A,18B,18C,18D).The recognition of groove pancreatitis is important for differentiation from pancreatic and duodenal carcinomas.沟部胰腺炎（胰头部慢性局限性胰腺炎）是
45、一种局灶性慢性胰腺炎，发生于胰头、十二指肠、胆总管之间的凹槽内。沟部胰腺炎的主要MRI为胰头及增厚的十二指肠壁之间片状的纤维化肿块，同时伴有十二指肠狭窄和十二指肠壁的囊性改变（图18A，18B，18C，18D）。提高对沟部胰腺炎的认识在胰腺和十二指肠肿瘤的鉴别诊断中是非常重要的。Fig.18A.57-year-old man with 2-year history of chronic pancreatitis and groove pancreatitis.Contrast-enhanced CT scan shows solid mass with small low-density cy
46、stic lesion(arrow)lying in groove between head of pancreas(P)and duodenum(D).Axial T1-weighted fat-suppressed spoiled gradient-echo image shows low-signal-intensity mass(arrow)containing small cystic component and lying between high-signal-intensity pancreatic head(P)and duodenum.图18A。57岁，男。慢性胰腺炎和沟部
47、胰腺炎2年。对比增强CT示胰头（P）和十二指肠（D）间的凹槽内实性肿块，肿块内可见小囊性低密度病灶（箭头）。轴向T1WI示含小囊性成分的低信号肿块（箭）位于高信号的胰头（P）和十二指肠之间。Fig.18C.57-year-old man with 2-year history of chronic pancreatitis and groove pancreatitis.Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during arterial phase shows normal
48、 enhancement of pancreas and duodenal wall.Heterogeneous mass(arrow)has decreased enhancement due to fibrosis.Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo image obtained during venous phase shows delayed enhancement of heterogeneous mass(arrow)in groove due to fibrosis.P=pancreati
49、c head.图18C。同一病例。动脉期轴向增强T1WI示胰腺和十二指肠壁正常强化。不均质肿块因纤维化而呈低强化（箭）。静脉期图像示肿块延迟强化（箭头）。P=胰头。Patients with suspected chronic pancreatitis may benefit from undergoing MRI as an adjunct or alternative to ERCP and CT.In particular,MRI may be useful in the evaluation for strictures,anatomic variants,and dilatation of the pancreatic duct and for associated fluid collections.疑似慢性胰腺炎患者可以MRI检查作为一种对ERCP和CT辅助或替代。MRI可有效评估狭窄，解剖变异，胰管扩张及液体积聚。
