AJR 2004; 183:1645-1652
© American Roentgen Ray Society
MRI of Pancreatitis and Its Complications: Part 2, Chronic Pancreatitis
Frank H. Miller1,
Ana L. Keppke1,
Anubha Wadhwa1,
John N. Ly2,
Kshitij Dalal1 and
Vilim-Alan Kamler1
1 Department of Radiology, Northwestern Memorial Hospital, Northwestern
University, The Feinberg School of Medicine, 676 N Saint Clair St., Ste. 800,
Chicago, IL 60611.
2 Department of Radiology, Saint Vincent Medical Imaging, 438 Victoria St.,
Level 5, Darling Hurst, NSW 2010, Australia.
Received April 2, 2004;
accepted after revision June 8, 2004.
Address correspondence to F. H. Miller.
Introduction
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. ERCP 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 [1,
2]. MRI provides noninvasive
biliary and pancreatic duct imaging and accurate characterization of
pancreatic and peripancreatic pathology. The purpose of this pictorial essay
is to illustrate the emerging role of MRI in the diagnosis of chronic
pancreatitis and its associated complications.
Chronic Pancreatitis
Diagnosis
The diagnosis of chronic pancreatitis on MRI is based on signal intensity
and enhancement changes as well as on morphologic abnormalities in the
pancreatic parenchyma, pancreatic duct, and biliary tract. The imaging
features of chronic pancreatitis can be divided into early and late findings.
Early findings include low-signal-intensity pancreas on T1-weighted
fat-suppressed images, decreased 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.
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). Chronic inflammation and
fibrosis diminish the proteinaceous fluid content of the pancreas, resulting
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. 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 [3] (Fig.
2A,
2B,
2C).
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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.
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Fig. 1B. —24-year-old woman with small pancreatic duct stone causing
duct obstruction and segmental pancreatitis. 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.
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Fig. 1C. —24-year-old woman with small pancreatic duct stone causing
duct obstruction and segmental pancreatitis. 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 developed atrophic changes in
this area that led to resection of pancreatic tail.
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Fig. 1D. —24-year-old woman with small pancreatic duct stone causing
duct obstruction and segmental pancreatitis. 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 MRI. It, however, also
illustrates the advantage of MRI in showing changes of signal intensity
associated with chronic pancreatitis that are not visible on CT.
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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 pancreatitis.
Calcifications are not as well seen on MRI as on CT.
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Fig. 2B. —46-year-old man with history of chronic pancreatitis due to
alcohol abuse. 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 due to chronic pancreatitis. Dilated
pancreatic duct (arrows) is visualized more clearly after contrast
administration.
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Fig. 2C. —46-year-old 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 delayed enhancement of pancreas from
chronic pancreatitis with pancreas becoming brighter than normal pancreas,
which enhances rapidly and washes out.
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Duct Abnormalities
ERCP is the standard of reference for imaging the pancreaticobiliary system
because of its high image resolution and the advantage of allowing therapeutic
intervention. ERCP is useful especially for depicting side branch changes of
early chronic pancreatitis. MR cholangiopancreatography (MRCP) is an
alternative for patients in whom ERCP failed and in those who cannot tolerate
this procedure [4] (Figs.
3A,
3B,
4,
5). The administration of
secretin during MRCP may help detect subtle side branch abnormalities and
allows noninvasive assessment of exocrine pancreatic function. In addition,
MRCP is highly accurate for identifying pancreas divisum
[5]
(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 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).
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Fig. 3A. —55-year-old woman with abdominal pain, weight loss, and
history of pancreatitis. Coronal T2-weighted thick-slab RARE image shows
beaded pancreatic duct and pseudocyst (arrow) from chronic
pancreatitis. Stomach is distended and filled with fluid.
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Fig. 4. —61-year-old woman with history of chronic pancreatitis.
Coronal T2-weighted HASTE image shows high-signal-intensity dilated main
pancreatic duct with multiple dilated side branches (arrows). These
findings constitute important early features of chronic pancreatitis.
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Fig. 5. —61-year-old woman with left lower quadrant pain and abnormal
findings on CT scan (not shown) that revealed cystic lesion of pancreatic
tail. Coronal T2-weighted thick-slab RARE image shows mild dilatation of side
branches (arrows) of pancreatic duct (PD). Main pancreatic duct and
common bile duct (CBD) have normal caliber. Multiseptated pseudocyst (P) is
seen in region of pancreatic tail.
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Fig. 6. —53-year-old woman with history of cholecystectomy who
presented with jaundice, 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.
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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 pancreatic duct is dilated and irregular, and there is mild
dilatation of side branches. Note diverticulum (curved arrow) arising
from duodenum. Common bile duct is minimally prominent.
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Fig. 8. —69-year-old man with chronic pancreatitis. Axial T2-weighted
HASTE image shows irregular dilated 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.
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CT is more sensitive than MRI for the detection 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 difficult on MRI
(Fig. 1A,
1B,
1C,
1D).
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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. 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.
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Fig. 9B. —46-year-old man with history of chronic pancreatitis due to
alcohol abuse. Axial T2-weighted HASTE image shows stone (arrow) in
main pancreatic duct delineated by high-signal-intensity fluid.
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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 = duodenum.
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Complications
Pseudocysts
Pseudocysts are encapsulated collections of pancreatic secretions that
occur in or around the pancreas. Although most resolve spontaneously,
complications such as infection, hemorrhage, and gastric or biliary
obstruction may occur (Fig.
11A,
11B). Pseudocysts can be
communicating with the main pancreatic duct
(Fig. 12) or noncommunicating
(Fig. 13). MRI can depict
pseudocysts and can be used to characterize their content and thus to guide
drainage.
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Fig. 11A. —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 communicate with pancreatic duct.
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Fig. 11B. —52-year-old man with history of recurrent pancreatitis. 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 infection, and it may
require prompt drainage.
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Fig. 12. —55-year-old woman with abdominal pain, weight loss, and
history of pancreatitis. Axial T2-weighted HASTE image shows
high-signal-intensity pseudocyst (P) in pancreatic head with dilated and
irregular pancreatic duct. Pseudocyst can be seen communicating with main
pancreatic duct (arrow).
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Fig. 13. —59-year-old man with history of acute and chronic
pancreatitis. Axial enhanced T1-weighted fat-suppressed spoiled gradient-echo
image obtained during venous phase shows multiple pseudocysts (P) lying
anterior and superior to pancreatic head and body genu. Pancreas is
hyperintense due to delayed enhancement. GB = gallbladder.
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Vascular
Arterial pseudoaneurysms, hemorrhage into pseudocysts, arterial bleeding,
and splenic 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. Short gastric and gastroepiploic
collaterals constitute useful complementary findings (Fig.
14A,
14B).
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Fig. 14A. —46-year-old 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.
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Fig. 14B. —46-year-old 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 collateral vessels (arrows),
which is suggestive of splenic vein occlusion. Pancreatitis with pseudocyst
caused splenic and portal vein thrombosis.
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Biliary
The biliary complications of chronic pancreatitis include
choledocholithiasis, fistulas, and dilatation of the common bile duct due to
inflammatory strictures. The typical appearance of benign strictures on MRCP
is gradual tapering with a funnellike narrowed segment
(Fig. 15).
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Fig. 15. —59-year-old man with history of chronic pancreatitis. MR
image was obtained to evaluate biliary tract and complex pseudocysts seen on
prior CT scan (not shown). Coronal T2-weighted thick-slab RARE image shows
dilated common bile duct with funnel-shaped narrowing (arrowhead) due
to stricture in common bile duct. 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. GB =
gallbladder.
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Chronic Pancreatitis Versus Pancreatic Carcinoma
Differentiating between an inflammatory mass due to chronic pancreatitis
and pancreatic carcinoma on the basis of imaging criteria remains difficult.
Decreased T1 signal intensity with delayed enhancement after gadolinium
administration as well as dilatation and obstruction of the pancreaticobiliary
ducts can be seen in both diseases
[6]. Irregularity of the
pancreatic duct, intraductal or parenchymal calcifications, diffuse pancreatic
involvement, and normal or smoothly stenotic pancreatic duct penetrating
through the mass ("duct penetrating sign") favor the diagnosis of
chronic pancreatitis over cancer
[6] (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 of the perivascular fat planes favor the diagnosis of cancer.
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Fig. 16A. —58-year-old woman with breast cancer and chronic pancreatitis
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
gradient-echo image shows low-signal-intensity pancreas due to chronic
pancreatitis.
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Fig. 16B. —58-year-old woman with breast cancer and chronic pancreatitis
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 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.
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Fig. 16C. —58-year-old woman with breast cancer and chronic pancreatitis
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 T2-weighted HASTE image shows
markedly dilated main pancreatic duct (arrow) penetrating through
pancreas with chronic inflammatory and fibrotic changes: "duct
penetrating sign." This finding suggests chronic pancreatitis over
adenocarcinoma.
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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 delineated on unenhanced T1-weighted fat-suppressed images
and multiphasic enhanced sequences (Fig.
17A,
17B,
17C,
17D).
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Fig. 17A. —71-year-old woman with weight loss due to adenocarcinoma of
pancreas with associated chronic pancreatitis. Axial contrast-enhanced CT scan
shows atrophy of pancreatic tail and duct dilatation (arrow) to level
of suspected mass, which is difficult to see.
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Fig. 17B. —71-year-old woman with weight loss due to adenocarcinoma of
pancreas with associated chronic pancreatitis. Axial T2-weighted HASTE image
shows dilatation of pancreatic duct with abrupt termination (arrow)
due to tumor. T2-weighted images are helpful in showing high-signal-intensity
fluid in pancreatic duct.
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Fig. 17C. —71-year-old woman with weight loss due to adenocarcinoma of
pancreas with associated chronic pancreatitis. Axial T1-weighted
fat-suppressed spoiled gradient-echo image shows low-signal-intensity mass
(arrowhead), measuring less than 1 cm, in pancreatic neck due to
adenocarcinoma. Note atrophy and decreased signal intensity of pancreatic tail
(curved arrow) related to associated chronic pancreatitis. Normally
high signal intensity of pancreatic head (straight arrow) is
preserved.
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Fig. 17D. —71-year-old woman with weight loss due to adenocarcinoma of
pancreas with associated chronic pancreatitis. 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 and smooth dilatation of
pancreatic duct with associated chronic pancreatitis in upstream pancreas.
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Groove Pancreatitis
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 sheetlike 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 [7].
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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 cystic lesion (arrow) lying in groove between head of
pancreas (P) and duodenum (D).
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Fig. 18B. —57-year-old man with 2-year history of chronic pancreatitis
and groove pancreatitis. 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.
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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 enhancement of
pancreas and duodenal wall. Heterogeneous mass (arrow) has decreased
enhancement due to fibrosis.
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Fig. 18D. —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 venous phase shows delayed enhancement of
heterogeneous mass (arrow) in groove due to fibrosis. P = pancreatic
head.
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Conclusion
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.
References
- Sica GT, Miller FH, Rodriguez G, McTavish J, Banks PA. Magnetic
resonance imaging in patients with pancreatitis: evaluation of signal
intensity and enhancement changes. J Magn Reson
Imaging 2002;15:275
–284[Medline]
- Semelka RC, Kroeker MA, Shoenut JP, Kroeker R, Yaffe CS, Micflikier
AB. Pancreatic disease: prospective comparison of CT, ERCP, and 1.5-T MR
imaging with dynamic gadolinium enhancement and fat suppression.
Radiology1991; 181:785
–791[Abstract/Free Full Text]
- Semelka RC, Shoenut JP, Kroeker MA, Micflikier AB. Chronic
pancreatitis: MR imaging features before and after administration of
gadopentetate dimeglumine. J Magn Reson Imaging1993; 3:79
–82[Medline]
- Sica GT, Braver J, Cooney MJ, Miller FH, Chai JL, Adams DF.
Comparison of endoscopic retrograde cholangiopancreatography with MR
cholangiopancreatography in patients with pancreatitis.
Radiology1999; 210:605
–610[Abstract/Free Full Text]
- Bret PM, Reinhold C, Taourel P, Guibaud L, Atri M, Barkun AN.
Pancreas divisum: evaluation with MR cholangiopancreatography.
Radiology1996; 199:99
–103[Abstract/Free Full Text]
- Johnson PT, Outwater EK. Pancreatic carcinoma versus chronic
pancreatitis: dynamic MR imaging. Radiology1999; 212:213
–218[Abstract/Free Full Text]
- Irie H, Honda H, Kuroiwa T, et al. MRI of groove pancreatitis.
J Comput Assist Tomogr1998; 22:651
–655[Medline]
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Introduction
Chronic Pancreatitis
