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Pancreatic MRI
An Electronic Atlas of Pancreatic Imaging
Bonnie Garon, MD
Howard Youngworth, MD
Lusine Tumyan, MD
Miriam Romero, MD
Suzanne Palmer, MD
Keck School of Medicine
University of Southern California
Purpose
• Understand the role of routine MRI, MR
Pancreatography, and Secretin stimulation MRI
in evaluation of pancreatic pathology
• Review normal anatomy and common variants
as demonstrated by MRI
• Demonstrate the MRI characteristics of various
pathological conditions with their clinical
presentations and correlative imaging
Pancreatic Embryology
• Pancreas arises from two
diverticula of the primitive
foregut
– Ventral (anterior) bud –
• develops into the
hepatobiliary system
• gives off a small bud from
the bile duct close to the
duodenum (ventral
pancreatic bud) which
eventually forms the
uncinate process and
inferior portion of the head
of the pancreas
– Dorsal (posterior) bud –
• forms the body, tail and part
of the head of the pancreas
*Adapted from Reference
Pancreatic Duct
•
Main Pancreatic duct of Wirsung
– Formed from distal portion of
embryologic dorsal duct and
ventral duct
– Drains through major papilla
– Maximum diameter 2-3 mm
– Major drainage in 90%
•
Accessory Pancreatic Duct of
Santorini
– Proximal portion of embryologic
dorsal duct
– Drains through minor papilla
– Present in 44%
•
CBD drains via major papilla in 100%
Minor papilla
Dorsal duct
Ampulla of Vater
Ventral duct
*Adapted from Reference
* Adapted from Reference 4
Main pancreatic
duct
Thick Slab MRCP
Pancreatic Divisum
• Most common congenital
anomaly (10%)
Dorsal Duct
• Failure of fusion of the
pancreatic ducts
• Ventral duct of Wirsung,
which drains head of
pancreas through major
papilla
• Dorsal duct of Santorini,
which drains the body of
the pancreas by minor
papilla
Ventral Duct
Thick Slab MRCP
Dorsal Duct
Ventral Duct
T2 HASTE
Pancreatic Anatomy
•
Located in the anterior pararenal
space
•
Vascular landmarks
Normal Pancreas
– Splenic artery and vein
– Superior mesenteric artery and
vein
•
12-15 cm long
•
Vascular supply
– Gastroduodenal artery,
pancreatico-duodenal artery and
splenic artery
•
T2 Axial
Normal Pancreas
Imaging Appearance
– High T1 signal intensity and low
T2 signal intensity, similar to liver
T1 Axial
Endoscopic Retrograde
Cholangiopancreatography
Advantages
Disadvantages
• Therapeutic and diagnostic
procedure
• Technically difficult with a
failed cannulation rate of up
to 11%
• Direct inspection of the
papilla of Vater and
ampullary tumors
• ERCP can be superior in
diagnosis of intraductal
papillary mucinous tumors
• Invasive procedure with
complication rate of 5-7 %
and mortality rate of 0.2 %
• Limited in evaluation of
tumor extension
• Cannot be performed in
patients with pancreaticoenteric anastomosis
Computerized Axial Tomography
Advantages
Disadvantages
• More manageable in severely ill
• Irradiation
patients
• Cost and availability relative to • Iodinated contrast media
MRI and ERCP
• High spatial resolution
• Air and calcification are easily
recognizable
IPMT
Ultrasound
Advantages
Disadvantages
• Noninvasive, portable,
widely available and
economical
• Operator and patient
dependent
• Color doppler
evaluation of
peripancreatic
vascular structures
allows determination of
tumor resectability
• Enteric gas limits
evaluation
MR Cholangiopancreaticography
Advantages
• Noninvasive alternative to
diagnostic ERCP
Disadvantages
• Patient dependent
• Artifacts may obscure areas of
• Useful in proximal obstruction interest
where ERCP is limited
• Poor visualization of
• May be performed in post
calcifications
operative patient
• Cost
• Improved tissue
characterization when
compared to CT
anastomosis
Routine Pancreatic MRI Technique
•
NPO
•
Phased-array surface coil
•
Breath held with ultra fast
sequences
•
T2 axial
May be performed with or
without MRCP sequences
imaging IV Contrast
T1 in phase
T1 out of phase
Routine Pancreatic MRI Technique
Sequence (all breath held) Acquisition
time
Coronal T2 (HASTE,
ssFSE)
20 sec
Axial T2 (HASTE, ssFSE)
20 sec
Axial T2 STIR
20 sec
Axial T1Gradient echo - in 20-30 sec
and out of phase
Axial/coronal Post
contrast T1 /phase
art/venous/equilib
20-30 sec
Total imaging time
< 5 minutes
Arterial phase
Venous phase
Equilibrium phase
MRCP Technique
Thick Slab
•
Heavily T2 weighted images
– Stationary, slow flowing liquids
high SI
– Fat suppression to allow higher
SNR and contrast noise ratio
– Background tissue SI very low
or absent
– TR 3000, TE 1100
– 3D
•
•
•
•
•
Slab thickness 60-80 mm
Sat band over CSF
FOV large enough to prevent
wrap around
Multiple planes of acquisition
– Coronal and coronal oblique
– Pin wheel around central axis
Acquisition time 2-3sec
NSF Prevention
• Calculate GFR in patients with high risk for renal
insufficiency
– Over age 65
– Diabetes, Hypertension
– Kidney disease, dialysis
• Choice of contrast based on GFR
– > 60 – Contrast agent of choice (Magnevist)
– 30-60 (moderate kidney impairment)
*Adapted from Reference 7
• Should not exceed recommended dose of contrast, Multihance
preferred at our institution
– <30 (severe kidney impairment)
• Use of contrast should be carefully considered
• If contrast is absolutely necessary, must sign “MR contrast in
Renal dysfunction/ Dialysis patient” consent
• If on dialysis, must receive dialysis immediately after
Dynamic MR Pancreatography with
Secretin
•
Improves visualization of
pancreatic ductal system
•
Improves the detection of:
– Normal ducts, pancreatic
divisum, ductal stricture,
chronic pancreatitis
associated with marked ductal
dilatation
•
Mechanism of Secretin
– Exogenous administration of
secretin stimulates the
secretion of fluid and
bicarbonate by the exocrine
pancreas
– Manometric studies show an
increase in duct pressure at 1
minute and return to basal
pressure at 5 minutes
– Increases fluid secretion by
ductal cells and
simultaneously increases
sphincter of Oddi tone
*Adapted from Reference 8
Dynamic MR Pancreatography with
Secretin
• Dosing and Technique
– IV administration of 1 mL of
secretin per 10 kg of body weight
– Image before and repeat every 2
minutes for 16 minutes after
administering secretin
– Abnormal if duct remains greater
than 1 mm above baseline after 6
minutes
Pancreatic duct
Pre-Secretin Administration
• FDA-Risks and Side effects
– Some common side effects with
secretin include:
• Nausea, flushing, abdominal
pain, vomiting
– Secretin may cause an allergic
reaction
• A test dose of secretin should
be given to check for an allergic
reaction
Pancreatic duct
Normal Appearance s/p Secretin Administration
Secretin Stimulation in a Normal
Pancreatic Duct
Pancreatic
duct
Pre Administration of Secretin
Pancreatic
duct
6 minutes after administration of Secretin
Acute Pancreatitis
•
Most common benign disease
involving pancreas
•
Most common cause is
choledocholithiasis and alcohol
use
•
Temporary process with potential
for restoration of normal anatomy
•
Complications include acute fluid
collections, psuedocyst formation,
pancreatic abscess and pancreatic
necrosis
•
Imaging
– Imaging used to detect cause or
complications
– Increased T2/Decreased T1 signal
from edema
– Normal MRI appearance is seen in
29% of patients with acute
pancreatitis
Increased T2 SI
Decreased T2 SI of
peripancreatic inflammation
T2 Axial
Pancreatic head inflammation
T2 Axial
T2 Coronal
Pancreatic Pseudocyst
•
Pancreatic fluid collection
enclosed by non-epithelialized
fibrous wall
•
Occurs approximately 4 weeks
after onset of pancreatitis
•
May be intra or extrapancreatic
•
Can communicate with adjacent
structures
•
Spontaneously resolves in up to
60%. Those that don’t resolve can
be complicated by hemorrhage or
infection
•
Pseudocyst
Pseudocyst
Pseudocyst
T2 HASTE Coronal
T2 HASTE Axial
All uncomplicated pseudocysts
have high T2 SI and low T1 SI
T1 Axial
Necrotizing Pancreatitis
• Complication of severe acute
pancreatitis
Non-enhancing body and
tail c/w necrosis
• Focal/diffuse area of
nonviable pancreas
• Tends to affect body/tail,
spares head due to abundant
vascular supply
• Imaging
– Areas of absent enhancement
– Heterogeneous signal
intensity
Contrast CT
Area of necrosis
T1 Axial
Chronic Pancreatitis
•
Continued inflammatory disease of
pancreas characterized by irreversible
damage to anatomy and function
•
Mainly caused by alcohol abuse
•
Calcifying or Obstructive
•
Focal chronic pancreatitis is difficult
to differentiate from adenocarcinoma
due to similar imaging findings
•
Imaging
– Loss of fat signal on fat
suppressed images
– Diminished contrast enhancement
– Multifocal dilatation and stenosis
of duct due to fibrosis
– Focal areas of decreased signal on
T1 and T2 images from
calcifications
Low signal, apparent pancreatic
head mass (pathology proven
chronic pancreatitis)
T2 Coronal
T1 Axial
Dynamic Imaging of Chronic
Pancreatitis
• Visualization of the minor duct and the side
branches is significantly improved
– Pitfalls
• Pre-existing ductal strictures
• Ducts greater than 5 mm prior to secretin administration
• Negative predictive value increases from 84% to
98% using dynamic pancreatography
• Study confidently shows that patients with
suspected pancreatic disease did not have the
disease, which may prevent the need for ERCP
Pancreatic Pathology: Cystic Fibrosis
•
Autosomal recessive, 1 in 20002500 live births
•
Dysfunction of exocrine glands
forming thick tenacious material
Fatty replacement of the head
Fatty replacement of the head
•
Multisystem disease that affects
lungs, GI tract, liver, biliary tract,
pancreas, and reproductive tract
•
Presentation
– Steatorrhea, malabsorption
– Pancreatitis
– Diabetes Mellitus
Fatty replacement of the body
Fatty
Fattyreplacement
replacementof
ofthe
thebody
tail
and loss of lobulations
Fatty replacement of the tail
•
Imaging
– Diffuse pancreatic atrophy
– Complete/Partial fatty
replacement
– Calcific chronic pancreatitis
– Loss of lobular contour
T1 Axial
T2 HASTE
Axial
T1 Axial
T2 HASTE
Axial
T1 Axial
T2 HASTE Axial
Pancreatic Pathology: Cystic Fibrosis
• Three imaging patterns
– Enlarged, lobulated
pancreas with complete
fatty replacement
– Atrophic pancreas with
partial fatty replacement
– Atrophic pancreas without
fatty replacement
Fatty replacement of pancreas
T1 Axial
Fatty replacement of pancreas
T1 Post contrast Fat Sat Axial
Primary Hemochromatosis
•
Autosomal recessive
•
Excessive absorption and
parenchymal retention of dietary Fe
that favors accumulation within nonRES organs
•
DI liver and pancreas
DI liver and pancreas
Clinical Manifestations
– Cirrhosis, glucose intolerance, heart
failure, abdominal pain, arthropathy,
and skin discoloration
•
Complications
– HCC, liver failure, cardiomyopathy,
diabetes
•
DI liver and pancreas
T2 Axial
Imaging
– Decreased SI (DI) on T1 and T2
weighted images in pancreas and
liver due to paramagnetic effect of
iron
– Changes most conspicuous on
gradient echo imaging
– Spleen and bone marrow spared
T2 Axial
T1 Gradient Echo
Secondary
Hemochromatosis/Hemosiderosis
• Iron deposition due to iron
overload and RES cell
deposition
DI in liver/spleen/pancreas
/bone marrow
• Pancreas does not contain
RES cells and usually not
effected
• Estimated RES cell capacity =
10 gm, which corresponds with
40 units of blood
T2 Axial
DI in liver/spleen/pancreas
/bone marrow
• After RES cell saturated,
parenchymal cell deposition
will occur, causing decreased
signal within the pancreas
T2 SSFSE
Pancreatic Ductal Adenocarcinoma
Pancreatic head mass
•
5th leading cause of cancer
deaths
•
Diabetes and smoking doubles
the risk
•
Most frequent cause of
malignant obstructive jaundice
Pancreatic head mass
•
New onset diabetes in 25 – 50%
T1 Fat Sat Axial
Pancreatic head mass
•
Imaging
– Tumor most visible on T1 post
Gd
– Enhances less than adjacent
pancreatic tissue on arterial
and portal venous phases
– Delayed phase enhancement is
variable due to desmoplastic
reaction
Pancreatic head mass
Pancreatic head mass
T2 Axial
T1 Arterial Phase Axial
T1 Venous Phase Axial
T1 Equilibrium Phase Axial
Mucinous Cystadenoma
• 10% of pancreatic cysts, 1%
pancreatic neoplasms
• Low malignant potential, usually
in pancreatic tail/body
Cystic mass in pancreatic tail
(pathology proven mucinous
cystadenoma)
• Commonly asymptomatic, but may
present with pain, anorexia
• Treatment- surgical resection due
to invariable transformation into
cystadenocarcinoma
• Imaging
– Well demarcated hypovascular
thick wall mass of 2-36 cm with
high T2 SI and low T1 SI
– Multi/unilocular large cysts with
thin septa, usually less than 6
cysts. May contain peripheral
calcifications
– Nodules may indicate malignant
transformation
T2 Coronal
T2 Axial
T1 Axial
Intraductal Papillary Mucinous Tumor
• Rare intraductal tumor
originating from epithelial lining
with large amounts of
mucinous secretions
• Recurrent episodes of dull
pain/acute pancreatitis
• Low grade malignancy with
better prognosis than
adenocarcinoma
• Treatment- Whipple
Thick Slab MRCP
Intraductal Papillary Mucinous Tumor
•
Main Duct IPMT
– Dilatation of main pancreatic duct,
branch ducts and papilla
– Pancreatic atrophy
•
•
Segmental
– Cyst in body/tail with normal
remaining pancreas
– Cyst in pancreatic head with
dilatation of duct
T2 Coronal
T2 Coronal
Branch Duct IPMT
• Mainly in uncinate process
• Severe pancreatic atrophy
• Complications: seeding to main
pancreatic duct resulting in main
duct IPMT
T2 Axial
T2 Axial
Carcinoid
• Metastatic carcinoid to
the pancreas is rare
• MR imaging
– low signal intensity
on T1-weighted
images
– high signal intensity
(HS) on T2-weighted
due to complex
cystic nature
SSFE
HS masses in
HS masses
pancreatic
pancreatic
head/tail
tail
HS masses in pancreatic
body/tail
Hypo-enhancing
masses
in pancreatic tail
Hypo-enhancing masses
in pancreatic tail
T2 Axial
T2 Axial
T2 Coronal
T1Arterial Phase Axial
T1 Venous Phase Axial
Insulinoma
• Most common functioning
islet cell tumor
• Single benign adenoma 80
to 90%
Low SI mass in pancreatic
tail (pathology proven
Enhancing mass in
insulinoma)
pancreatic
tail (pathology
Enhancing mass
in
proven
insulinoma)
pancreatic tail (pathology
proven insulinoma)
• No predilection for any
part of the pancreas
• 70% less than 1.5 cm
• Low signal intensity on
fat-suppressed T1W1
• Hyperintense on dynamic
contrast enhanced
T1 Axial
T1 Arterial Phase Axial
T1 Venous Phase Axial
Insulinoma
Pancreatic Trauma
• Present with laceration
in pancreas or
hematoma
LS – area of post-operative
hematoma
• Due to blunt trauma
(MVA) or due trauma in
region like surgical
intervention close to
pancreas
T2 Axial
T1 Out of Phase Axial
T1 Arterial Phase Axial
Pancreatic Transplantation
• Used to manage certain
cases of complicated type 1
diabetes mellitus
Pancreatic transplant
• Susceptible to postoperative
complications like arterial
and venous thrombosis
• Artery and venous supply
usually anastomosed to iliac
vessels
T2 Axial
Pancreatic transplant
• Imaging-hyperintense to
adjacent organs on T1-fat
suppressed images, avidly
enhances
T1 Axial
Pancreatic Arteriovenous Malformation
Multiple cystic structures in
pancreas
Flow voids c/w AVM
Color Doppler flow in
region of cysts
AVM
AVM
T1 Coronal
T1 Coronal Post Contrast
Angiogram
References
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C Matos, O Cappeliez, C Winant, E Coppens, J Devière, T Metens. MR Imaging of the Pancreas: A Pictorial Tour. RadioGraphics, Jan
2002; 22: 2.
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D Wolfgnang. Radiology Review Manuel. 5th ed. Philadelphia: Lippincott, Williams and Wilkins, 2003.
3.
K.J. Mortelé, P.R. Ros. Cystic Focal Liver Lesions in the Adult: Differential CT and MR Imaging Features. RadioGraphics, Jul 2001;
21: 895 - 910.
4.
Mergo et al. Pancreatic Neoplasms: MR Imaging and Pathologic Correlation. Radiographics, March 1997; 17:281-201.
5.
E.S. Siegalman. Body MRI. Philadelphia, Pa: Elsevier Saunders, 2005.
6.
Food and Drug Administration, Human Secretin 7/13/04, viewed 10/01/07,
http://www.fda.gov/cder/consumerinfo/druginfo/Human_Secretin.HTM
7.
Clinical Correlations, FDA advises caution with gadolinium based contrast 12/27/06, NYU School of Medicine, viewed 10/15/07,
http://www.clinicalcorrelations.org/wp-content/uploads/nfd.jpg
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Thailand Cyber University, Digestive Tract 1, viewed 10/10/07,
http://www.thaicyberu.go.th/OfficialTCU/main/digestivesystem1/Content/211.gif
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Leyendecker et al. MR Cholangiopacreatography: Spectrum of Pancreatic Duct Abnormalities. Radiology, December 2002;
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10.
Minami et al. Cystic Neoplasms of the Pancreas: Comparison of MR Imaging with CT. Radiology, April 1989;171:53-56.
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Brugge et al. Cystic Neoplasms of the Pancreas. New England Journal of Medicine, September 16, 2004; 351: 1218-26.