Gastrointestinal: Pancreas Flashcards
How do you know whether the pancreas echogenicity is normal?
The pancreas should be hyperechoic relative to the liver
Note: If it is hypoechoic to the liver, consider pancreatitis.
What is the brightest organ on non contrast T1 images?
The pancreas
Which portion of the pancreas is retroperitoneal?
Head and body (the tail is often intraperitoneal)
What are the major pancreatic changes in cystic fibrosis?
- Fatty replacement (more common, increased T1 signal)
- Fibrosis (decreased T1 and T2 signal)
Are pancreatic problems more common in pts diagnosed with cystic fibrosis in childhood or adulthood?
Adulthood
Note: Cystic fibrosis pts with residual pancreatic exocrine function tend to have bouts of recurrent acute pancreatitis (due to thick secretions). Small pancreatic cysts (1-3 mm) are also common.
What is the most common imaging findings in an adult with cystic fibrosis?
Complete fatty replacement of the pancreas
Lipomatous pseudohypertrophy of the pancreas
Enlarged pancreas with fatty replacement
Note: This is classically seen in pts with cystic fibrosis, but can also be seen in Shwachman-Diamond syndrome.
Fibrosing colonopathy
Wall thinking of the proximal colon as a complication of enzyme replacement therapy in pts with cystic fibrosis
Pediatric pt with persistent diarrhea, short stature, and eczema…
Think Shwachman-Diamond syndrome (the second most common cause of pancreatic insufficiency after cystic fibrosis)
Note: Short stature is due to metaphyseal achondroplasia.
Pancreatic lipomatosis
The accumulation of fat in the pancreatic parenchyma
Note: This is why the pancreas becomes more fatty as we age.
Differential for pancreatic lipomatosis
- Aging/obesity (most common in adults)
- Cystic fibrosis (most common in children)
- Cushing syndrome
- Chronic steroid use
- Hyperlipidemia
- Shwatchman-Diamond syndrome
Dorsal pancreatic agenesis is associated with…
- Diabetes (most beta cells are in the tail)
- Polysplenia
How can you differentiate severe pancreatic lipomatosis from pancreatic agenesis?
In pancreatic agenesis, there will not be a pancreatic duct (but there will be in pancreatic lipomatosis)
Etiology of annular pancreas
Embryologic defect (failure of the ventral bud to rotate with the duodenum)
Clinical presentation of annular pancreas
- Duodenal obstruction (pediatric)
- Pancreatitis (adult)
What determines whether pancreatic trauma is surgical or nonsurgical?
The integrity of the pancreatic duct (if the duct is damaged, they need surgery)
Common complications of pancreatic trauma
- Pancreatic duct injury (needs surgery)
- Pancreatic fistula
- Abscess formation
MVC
Pancreatic laceration
Traumatic pancreatitis in an infant…
Suspect non accidental trauma
How can you tell whether peripancreatic fluid is due to pancreatic trauma or aggressive hydration?
Look at the liver and IVC (large IVC and periportal edema favor aggressive hydration)
If you suspect a pancreatic duct injury on CT, what’s the next step?
MRCP or ERCP
Most common causes of pancreatitis
- Gallstones
- EtOH
- Recent ERCP
What medication is classically known to cause pancreatitis?
Valproic acid
What is the most common cause of pancreatitis in a child?
Trauma
What is the biggest factor in determining prognosis of acute pancreatitis?
Degree of pancreatic necrosis
When is the risk for infection greatest during acute pancreatitis?
Weeks 3-4 (anti-inflammatory period), due to translocation of intestinal flora
Note: Infection rarely occurs during the first 2 weeks (pro-inflammatory period).
What is the most important finding:
A. Pancreatic hemorrhage
B. Pancreatic necrosis
C. Pancreatic fluid collection
D. Infected pancreatic necrosis
D. Infected pancreatic necrosis
Note: Once a necrotic pancreas becomes infected, mortality is very high (50-70%).
Fluid collection around the pancreas 2 weeks after acute pancreatitis…
Acute peripancreatic fluid collection
Note: At 4 weeks, this starts being called a pseudocyst.
Fluid collection around the pancreas 5 weeks after acute pancreatitis…
Pseudocyst
Note: Prior to 4 weeks, this is called an acute peripancreatic fluid collection.
Fluid around the pancreas 3 weeks after acute necrotizing pancreatitis…
Acute necrotic collection
Note: After 4 weeks, this starts being called walled-off necrosis.
Fluid around the pancreas 6 weeks after acute necrotizing pancreatitis…
Walled-off necrosis
Note: Prior to 4 weeks, this is called an acute necrotic collection.
What are common vascular complications of acute pancreatitis?
- Splenic vein/portal vein thromboses
- Gastroduodenal artery/splenic artery pseudoaneurysms
What are common nonvascular complications of acute pancreatitis?
Abscess/infection
Pancreatic fluid collection containing gas with history of recent acute pancreatitis…
Concerning for infection (high mortality)
Where does the pancreatic duct enter the duodenum?
- The major pancreatic duct (Wirsung) drains to the inferior duodenal papilla
- The minor pancreatic duct (Santorini) drains to the superior duodenal papilla
Note: Santorini is Smaller and drains Superiorly.
What anatomic variant is this?
Pancreatic divisum (the most common anatomic variant of the pancreas)
Note: The main pancreatic duct now drains to the minor (superior) papilla. These pts are at increased risk for pancreatitis.
Pts with pancreatic divisum are at increased risk for…
Pancreatitis
What is the most common cause of chronic pancreatitis?
EtOH (followed by gallstones)
Early imaging signs of chronic pancreatitis
- Loss of T1 signal (normally the pancreas is the T2 brightest organ in the body)
- Delayed enhancement
- Dilated side branches
Late imaging findings of chronic pancreatitis
- Dilatation and beading of the pancreatic duct with calcifications (most characteristic)
- Uniform atrophy (but can have focal enlargement)
- Pseudocyst formation (30%)
Chronic pancreatitis
How can you differentiate pancreatic ductal dilatation in chronic pancreatitis from that in pancreatic cancer?
Irregular duct dilatation where the duct is less than 50% of the AP gland diameter favors chronic pancreatitis
Uniform duct dilatation where the duct is greater than 50% of the AP gland diameter favors pancreatic cancer (due to obstructive atrophy)
Complications of chronic pancreatitis
Pancreatic cancer (20 years of chronic pancreatitis = 6% risk of pancreatic cancer)
Most common cystic lesion in the pancreas
Psudocyst
Are simple pancreatic cysts common?
No, true epithelial lined pancreatic cysts are rare and tend to occur with syndromes
Simple pancreatic cysts are associated with…
- Von Hippel Lindau
- Polycystic kidney disease
- Cystic fibrosis
What are the main categories of cystic pancreatic neoplasms that do not communicate with the pancreatic duct and their typical age groups?
- Solid pseudopapillary epithelial neoplasm (daughter lesion, female in 30s)
- Mucinous cystic neoplasm (mother lesion, female in 50s)
- Serous cystic neoplasm (grandmother lesion, female in 70s)
75 y/o female
Serous cystadenoma (microcystic grandmother lesion)
What is the most common location for a pancreatic serous cystadenoma?
Pancreatic head (70%)
Note: Mucinous cystic neoplasm almost always occurs in the body/tail.
What is the most common location for a pancreatic mucinous cystic neoplasm?
Pancreatic body and tail (almost always)
Note: Serous cystadenoma usually occurs in the pancreatic head (70%).
Which pancreatic tumor communicated with the pancreatic duct?
Intraductal papillary mucinous neoplasms (both side branch and main branch types)
Which pancreatic neoplasm often has a central scar and/or central calcifications?
Serous cystadenoma (20%)
Note: Mucinous cystic neoplasm calcifications are usually peripheral.
Unilocular cyst with a lobulated contour in the pancreatic head…
Think serous cystadenoma
Note: These are more often multiloculated/microcystic, but can be unilocular and are more common in the pancreatic head.
Serous cystadenoma is associated with…
Von Hippel Lindau
Treatment for mucinous cystic neoplasm of the pancreas
Surgical excision (this is a premalignant lesion)
Which pancreatic neoplasm tends to be unilocular with peripheral calcifications?
Mucinous cystic neoplasm (macrocystic mother lesion)
Note: Calcifications in 20% of cases.
Is pancreatic serous cystadenoma benign or malignant?
Benign
Is mucinous cystic neoplasm of the pancreas benign or malignant?
Benign, but premalignant
Is solid pseudopapillary epithelial neoplasm of the pancreas benign or malignant?
Malignant, low grade
Mucinous cystic neoplasm (macrwocystic mother lesion)
Young female
Solid pseudopapillary epithelial neoplasm (daughter lesion)
Autoimmune pancreatitis is associated with…
IgG4 disease
Treatment for autoimmune pancreatitis
Steroids
Think autoimmune pancreatitis
Note: “Sausage shaped” with peripheral capsule-like delayed enhancement.
Groove pancreatitis (paraduodenal pancreatitis)
Note: Soft tissue in the pancreaticoduodenal groove.
Young male with history of malnutrition
Tropic pancreatitis (increased risk of adenocarcinoma)
Note: Calculi in dilated pancreatic ducts in a young pt with history of malnutrition.
18 y/o without history of malnutrition
Think hereditary pancreatitis (SPINK-1 gene mutation)
Note: These pts have an increased risk of adenocarcinoma.
What is the most common parasitic cause of pancreatitis?
Ascaris infection
Common manifestations of IgG4 disease
- Autoimmune pancreatitis
- Retroperitoneal fibrosis
- Sclerosing cholangitis
- Inflammatory pseudotumor
- Riedel’s thyroiditis
How can you differentiate autoimmune pancreatitis from chronic pancreatitis?
Autoimmune pancreatitis has no ductal dilatation and no calcifications
Which type of intraductal papillary mucinous neoplasm has the highest rate of malignancy
Main duct IPMN
Note: Side branch IPMNs are common and rarely malignant.
What features of an intraductal papillary mucinous neoplasm are concerning for malignancy?
- Main duct dilatation > 1 cm
- Diffuse or multifocal involvement
- Enhancing nodules
- Solid hypovascular mass
Which pancreatic tumor often has early, hemangioma-like peripheral enhancement?
Solid psudopapillary epithelial neoplasm
Main duct IPMN
Red arrow
Side branch IPMN
Note: There is also a main-duct IPMN here.
What are the two major types of solid pancreatic cancer?
- Ductal adenocarcinoma (hypovascualr)
- Islet cell/neuroendocrine (hypervascular)
Jaundice and migratory thrombophlebitis in an elderly pt with an enlarged gallbladder…
Think pancreatic ductal adenocarcinoma
Note: This is Trousseau syndrome (migratory thrombophlebitis in the setting of malignancy).
When does peak pancreatic parenchymal enhancement occur?
40 seconds
Note: The peak liver enhancement occurs later at 60 seconds (portal venous phase) due to dependence on portal blood flow.
What is the most common location for pancreatic ductal adenocarcinoma?
Pancreatic head (67%)
MRI appearance of pancreatic ductal adenocarcinoma
T1 hypointense mass relative to the intensely T1 bright pancreatic parenchyma
What contrast phase will a pancreatic neoplasm be most visible?
Pancreatic parenchymal phase at 40 seconds
Note: This is before the portal veinous phase (at 60 seconds) when pancreatic cancers may be isodense to background parenchyma.
Is pancreatic adenocarcinoma involving the gastroduodenal artery resectable?
Yes, the GDA comes out in a Whipple anyway
What is the most important part of staging pancreatic cancer?
Is the SMA or celiac axis involved?
Note: If these are involved, the cancer is not resectable.
What tumor marker is elevated in pancreatic cancer?
CA 19-9
What are the classic imaging findings of pancreatic cancer that may be seen on an upper GI series?
Mass effect on the duodenum:
- Inverted 3 sign (narrowing of the 2nd part of the duodenum to look like a backwards “3”)
- Wide duodenal sweep
Which hereditary syndromes are associated with pancreatic cancer?
- HNPCC
- BRCA mutation
- Ataxia-telangiectasia
- Peutz-Jeghers
When is a pancreatic adenocarcinoma considered a periampullary tumor?
If it originates within 2 cm of the major duodenal papilla
Note: Any tumor (pancreas, bile duct, duodenum) that meets this criteria is considered a periampullary tumor.
Best test to evaluate a periampullary tumor
MRI/MRCP
There is an increased risk of periampullary carcinomas in ______
Gardner’s syndrome
Islet cell neuroendocrine tumors are associated with…
- MEN 1
- Von Hippel Lindau
What is the most common type of islet cell neuroendocrine tumor?
Isulinoma (75%)
Note: These are almost always benign (90%). Gastrinoma is the second most common (30-60% of these are malignant).
Small pancreatic head mass in a pt with recently diagnosed jejunal ulcer…
Think gastrinoma (pancreatic islet cell neuroendocrine tumor secreting gastrin)
What is the most common pancreatic islet cell neuroendocrine tumor associated with MEN 1?
Gastrinoma
Zollinger-Ellison syndrome
Severe peptic ulcer disease secondary to a gastrinoma (gastrin secreting pancreatic neuroendocrine tumor)
Are nonfunctional pancreatic neuroendocrine tumors usually benign or malignant?
Malignant (80%)
Classic imaging appearance of a nonfunctional pancreatic neuroendocrine islet cell tumor
Large pancreatic mass with calcifications
Where are gastrinomas most likely to occur?
Near the duodenal papilla in the gastrinoma triangle
History of remote trauma
Think intrahepatic accessory spleen
Note: It should follow spleen on all MRI sequences (including restricting diffusion like normal spleen).
What nuclear imaging studies can be used to diagnose an intrahepatic accessory spleen?
- Heat treated RBCs
- Sulfur colloid
Pancreatic mass with tiger-stripe appearance on arterial phase imaging…
Think intrapancreatic accessory spleen
Note: The spleen demonstrates tiger striping on arterial phases.
