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1、MRI of Pancreatitis and Its Complications: Chronic Pancreatitis,宋承汝 2013.6.5,慢性胰腺炎及其并发症的MRI表现,Chronic pancreatitis is an inflammatory disease characterized by progressive and irreversible structural damage to the pancreas resulting in permanent impairment of both exocrine and endocrine functions. ER
2、CP is the gold standard for early chronic pancreatitis, but it is invasive. MRI may be an alternative for patients in whom CT or ERCP is contraindicated or not tolerated.MRI provides noninvasive biliary and pancreatic duct imaging and accurate characterization of pancreatic and peripancreatic pathol
3、ogy. 慢性胰腺炎是一种炎症性疾病,其特征是对胰腺逐步和不可逆转的结构性损坏,导致外分泌和内分泌功能的永久性受损。 ERCP是诊断早期慢性胰腺炎的金标准,但它是侵入性检查。 在CT或ERCP为禁忌或不能耐受时,MRI可作为替代。MRI提供非侵入性胆胰管成像和胰腺及胰周病变的征象。,The diagnosis of chronic pancreatitis on MRI is based on signal intensity and enhancement changes as well as on morphologic abnormalities in the pancreatic pa
4、renchyma, pancreatic duct, and biliary tract. The imaging features of chronic pancreatitis can be divided into early and late findings.,慢性胰腺炎MRI诊断是基于信号强度和增强的变化,以及胰腺实质,胰管和胆道形态的异常。慢性胰腺炎的影像特征可分为早期表现和晚期表现。,Early findings include low-signal-intensity pancreas on T1-weighted fat-suppressed images, decreas
5、ed and delayed enhancement after IV contrast administration, and dilated side branches. Late findings include parenchymal atrophy or enlargement, pseudocysts, and dilatation and beading of the pancreatic duct often with intraductal calcifications.,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
6、,假性囊肿,胰管扩张或呈串珠样,导管内常伴钙化。,MRI allows early recognition of chronic pancreatitis based on changes in pancreatic signal intensity; these changes are best visualized on unenhanced and gadolinium-enhanced T1-weighted fat-suppressed images (Fig. 1A, 1B, 1C, 1D).,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
7、化最佳(图1A,1B,1C,1D)。,Fig.1A. 1B.,Fig. 1A. 24-year-old woman with small pancreatic duct stone causing duct obstruction and segmental pancreatitis. Axial T2-weighted HASTE image shows slightly increased signal intensity of pancreatic tail (arrow) with mild dilatation of pancreatic duct.Axial T1-weighted
8、 fat-suppressed spoiled gradient-echo image shows abnormal low signal intensity of pancreatic tail (arrow) while remainder of pancreas has normal bright signal intensity. 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
9、spoiled gradient-echo image obtained during arterial phase shows delayed enhancement of pancreatic tail (arrow) relative to normal pancreas due to fibrosis. Patient later developed atrophic changes in this area that led to resection of pancreatic tail.Contrast-enhanced CT scan shows punctate high-de
10、nsity 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 MRI. It, however, also illustrates the advantage of MRI in showing changes of signal intensity associated with chronic panc
11、reatitis 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上是不可见的。,Fig.1C.1D.,Chronic inflammation and fibrosis diminish the proteinaceous fluid content of the pancreas, resulting
12、in the loss of the usual high signal intensity on T1-weighted fat-suppressed images. The normal pancreas enhances uniformly and intensely on early arterial phase contrast-enhanced T1-weighted images and exhibits rapid washout of gadolinium on subsequent images.,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
13、。正常胰腺动脉期均匀明显强化,并快速廓清。,In contrast, a pancreas with chronic fibrosis and glandular atrophy exhibits decreased and heterogeneous enhancement on early arterial phase images and increased relative enhancement on delayed images (Fig. 2A, 2B, 2C).,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,2
14、C),Fig. 2A. 2B.,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 parenchyma and irregular dilatation of main pancreatic duct (arrows), changes suggestive of chronic pancreatiti
15、s. 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 enhancement relative to marked enhancement seen normally. This decreased enhancement relates to fibrosis du
16、e 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。,Duct Abnormalities胰管异常,MRCP is highly accurate for
17、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 best 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。,