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Panc/GI
Review of anatomy and pathology with ultrasound images
61
Anatomy
Undergraduate 2
12/01/2015

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Term
When the pancreas grows circumferentially around the duodenum this is called __________ ________.
Definition
Annular pancreas
Term
The sudden onset of inflammation of the pancreas in which the pancreas function, pancreatic tissue and clinical symptoms return to normal if the causing factors are eliminated is called ______ _______.
Definition
acute pancreatitis
Term
The chronic relapsing of inflammation of the pancreas where the abnormal function persists even if the causes are removed is called _____ __________.
Definition
chronic pancreatitis
Term
The most common malignant tumor of the pancreas is called ________.
Definition
adenocarcinoma
Term
The most common islet tumor is called _______.
Definition
insulinoma
Term
What is the normal pancreatic size criteria?
Definition
Head: 2.5 cm
Body: 1.3 cm
Tail: 1.2 cm
Term
Describe the development of the pancreas.
Definition
- Begins as an outgrowth of the duodenum (which is part of the small intestine)
- At the foregut junction, 2 pancreatic buds called the dorsal & ventral endoderm are formed
- These two patches fuse to form the pancreas
Term
What is it termed when the pancreas fails to develop at birth or there is an absent portion of the pancreas?
Definition
Pancreatic Agenesis

(not diagnosed by US)
Term
What would you call underdevelopment of the pancreatic parenchyma?
Definition
Pancreatic Hypoplasia

(not diagnosed by US)
Term
What is a complete separation of the dorsal and ventral buds called?
Definition
pancreatic divisum
-occurs in 10% of the population
-predisposes pt to pancreatitis
-not typically diagnosed by US
Term
What is it termed when the entire pancreas lies to the left of the aorta and spine?
Definition
Ectopic Pancreas
-occurs in 2% of population
-Usually occurs in very thin patients w/a prominent left lobe
-If pancreas is displaced, the SMV will also be displaced
Term
What is the most common organ to find ectopic pancreatic tissue in?
Definition
duodenum
Term
What is the result of abnormal development of the pancreatic ducts?
Definition
Congenital Pancreatic Cysts
-Cysts are usually multiple, ranging from microscopic to 3-5cm
-Cysts may be assoc. w/polycystic kidney disease
(pt usually dies of renal failure before it gets to panc)
Term
What is the most lethal genetic disease in the Caucasian population?
Definition
Cystic Fibrosis
-Genetic disorder that results in a salt balance defect of the lungs
-also causes abnormal mucous secretions in the exocrine glands
-incidence is 1 in 2000
Term
[image]
Definition
Cystic Fibrosis US Appearance Panc: -Increased echogenicity -Poorly defined heterogeneous gland -enlargement Liver: -biliary cirrhosis Biliary: -Collapsed GB -GB wall thickening -Obstructed cystic duct from mucosal hyperplasia -Thick bile/sludge GI: -intestinal wall thickening
Term
The most common cause of acute pancreatitis is _________.
Definition
Biliary Tract Disease

Other causes:
-Alcohol Abuse
(alcohol & biliary account for 75-85% of cases)
-drug use (esp estrogen)
-surgical trauma
-ERCP complication
-PUD
-Panc Cancer
-Infectious Diseases
-Pregnancy
Term
How does Biliary Tract Disease lead to acute pancreatitis?
Definition
-Stone blocks ampulla
-Bile refluxed into pancreatic duct, irritating the panc
Term
How does ischemia affect the pancreas?
Definition
-inflammation results in edema
-edema compresses pancreatic vessels causing ischemia(inadequate blood supply to the organ)
Term
When activated digestive enzymes digest normal tissue protein in the pancreas, this is termed _______ _______.
Definition
Auto Digestion
-acute inflammation causes severe edema
-The interstitial fluid has a high concentration of enzymes
-These digestive enzyme become activated over time and digest normal tissue protein
-Auto digestion causes additional inflammation & may lead to other complications
Term
Symptoms of Acute Pancreatitis
Definition
-Sudden, severe pain in epigastrum & upper quadrants
-Pain is steady & band-like, radiating to the back
-Movement will aggravate the pain
-Pain is diminished when bending or standing
-Nausea/vomiting
-Fever, chills, leukocytosis (infection, abscess)
-Jaundice & pruritis (CBD compression)

Severe attacks may result in:
Abdominal distension (ileus), Guarding, Spasms, shock
Term
Acute Pancreatitis Labs and Prognosis
Definition
Labs:
-Increased amylase (w/in 72-94 hrs of onset)
-Amylase may be normal
-Increased lipase (w/in 72-94 hrs of onset)
-Increased glucose

Prognosis:
<10% mortality
Term
[image]
Definition

Acute Pancreatitis US Appearance:

-normal -Inflamed area is hypoechoic to anechoic & less echogenic than the liver (may have fatty liver) -Diffuse or focal enlargement (usually panc head) -Indistinct outline, poor definition, poor transmission (the splenic vein may not be visualized) -Edema can block the panc duct & the CBD

Term
[image]
Definition

Annular Pancreas

 (pancreas grows around duodenum)

Term
Hemorrhagic/
Necrotyzing Pancreatitis
Definition
Description:
-Severe form of pancreatitis
-Auto digestion causes a breakdown of panc tissue
-If bleeding occurs, it is called hemorrhagic pancreatitis
-If there is ischemia/necrosis, it is called necrotyzing pancreatitis
-Typically, both abnormalities are seen together
-Both necrotizing & hemorrhage pancreatitis are very serious complications & life-threatening

Lab:
-Increased Amylase

US Appearance:
-Pts will never have a normal pancreatic US
-Well-defined homogeneous, hypoechoic mass
-Well-defined complex mass
-Well-defined cystic mass
-Other complications (phlegmon, ascites)
Term
Pancreatic Phlegmon
Definition
-Results from severe acute pancreatitis
-When acute pancreatitis produces a mass effect, the inflammed area is called a pancreatic phlegmon
-Phlegmons may occur w/in the panc or beyond the panc

89% of hem/necr pancreatitis have a phlegmon

A common location for peripancreatic inflammation or a phlegmon is in the left anterior pararenal space
Term
When acute pancreatitis produces a mass effect, the inflammed area is called a ______________.
Definition
pancreatic phlegmon
Term
Pancreatic Phlegmon US Appearance
Definition
Findings (Pancreas):
Acute pancreatitis plus hypoechoic mass w/in panc

Findings (Peripancreatic Area):
Hypoechoic mass

Findings (Peritoneal Cavity):
-Tender, poorly defined hypoechoic mass w/in peritoneal cavity that cannot be explained away as normal anatomy
-Poor transmission (hard to distinguish from air-filled bowel)
Term
Pancreatic Ascites
Definition
-Pancreatic enzymes leaking into the abdominal cavity will also cause pancreatic ascites
-Enzymes may also inflame the diaphragm & chest cavity, causing a pleural effusion
Term
Pancreatic Pseudocyst
Definition
As a result of auto digestion, pancreatic fluid & enzymes may accumulate in an area & form a collection
This collection is called a pseudocyst
Pseudocysts have no lining, only fibrotic scarring

90% of pseudocysts are from acute pancreatitis or trauma
Term
Pancreatic Pseudocyst Locations
Definition
Pancreas
---Tail (most common)
---Head & body (rare)
Lesser sac (most common site)
Left anterior pararenal space (2nd most common site)
Posterior to the lesser sac & bordered by the anterior layer of Gerota’s fascia
Abdominal cavity (bowel, spleen, omentum)
Thoracic cavity (through diaphragmatic hiatus)
Term
Pancreatic Pseudocyst US Appearance
Definition
Findings:
Sharply, defined smooth walls
Posterior enhancement
Multiple septations
Multiple internal echoes (fluid may be echo-free)
Fluid-debris levels (hemorrhage or abscess)
Shadowing may occur from calcifications
Term
Portal Vein Thrombosis
Definition
Inflammation may cause sluggish flow through the splenic vein
Sluggish flow may cause thrombus, resulting in PHT & splenomagaly
Term
Most serious complication of acute/chronic pancreatitis is _______.
Definition
infection

It is the main cause of death from pancreatitis
Hard to deliver antibiotics (necrosis)
Untreated, an infected panc will cause death 80-100%
Term
Pancreatic Infection/Abscess
Definition
Infection of the pancreas may result in an abscess
Abscess present 2-5 weeks after the initial attack
The probability of abscess formation is related to the severity of the pancreatitis & the degree of tissue necrosis

Symptoms:
Chills, fever, leukocytosis
Treatment:
Hard to deliver antibiotics if there is necrosis
Term
Pancreatic Abscess US Appearance
Definition
Findings:
Similar in appearance to a pseudocyst
Smooth walls w/little or no internal echoes
Thick, irregular walls with internal echoes
The mass may range from anechoic to diffusely echogenic
Nonvisualized pancreatic abscess
Overlying bowel
Gas within the abscess
Term
Chronic Pancreatitis
Definition
-Chronic relapsing of inflammation
-Progressive destruction of the pancreas from repeated episodes of mild & subclinical acute pancreatitis
-Abnormal function/abnormal pancreatic tissue persists even if the causes are removed

Incidence:
Most common in males
Most common in alcoholics
Less likely in patients w/biliary tract disease
Term
Chronic Pancreatitis Physical Changes
Definition
-Atrophy
-Fat/Fibrosis
-Cysts
-Calcifications
----Assoc. w/alcoholic pancreatitis
----Stones w/in pancreas are almost always true stones lying w/in pancreatic ductules (Most common site = papilla)
-PD Dilatation
-CBD Dilatation
-Infection/Abscess
-Vascular Abnormalities
Term
Chronic Pancreatitis US
Definition
-Sometimes normal appearance
-Increased echogenicity (fat, fibrosis)
-Coarse, inhomogeneous texture (fat, fibrosis)
-Irregular contour of gland (atrophy)
-Focal or diffuse enlargement
-Pancreatic calcifications:
----Small stones make the pancreas mottled, speckled
----Numerous calcifications may shadow, making it difficult to identify the pancreas
-Pancreatic duct: Look for dilation & cause (stones)
Term
The normal gut wall thickness is:
Distended bowel: ________
Collapsed bowel:_________
Definition
Distended Bowel: 3mm
Collapsed Bowel: 5mm
Term
What is the McBurney’s point?
Definition
site of maximum tenderness in the right iliac fossa
1/3 distance from anterior superior iliac spine to the umbilicus (most common site for appendix)
Term
The measurement criteria for Acute Appendicitis is:
Diameter=
Wall thickness=
Definition
diameter = >6mm
wall thickness = >2mm
Term
The invagination of a bowel segment into the adjoining section is called ____________.
Definition
intussusception
Term
The measurement criteria for a Pyloris Stenosis is:
Length =
Thickness=
Diameter=
Definition
Length = ≥ 18mm
Thickness= ≥ 3mm
Diameter= ≥ 17mm
Term
Pancreatic Adenoma
Definition
A pancreatic tumor that may be benign or malignant
Could be Microcystic or Macrocystic
Term
Microcystic Adenoma
Definition
-aka Serous Cystadenoma
-Comprised of multiple tiny cysts (<2cm)
-Most common in older adult females
-60% in the body or tail
-lesions are totally benign (no malignant potential)
Term
Microcystic Adenoma US
Definition
US Appearance:
Findings:
Solid or partially solid
<2cm
Well-defined
Calcifications
Increased vascularity
Term
Macrocystic Adenoma
Definition
-aka Mucinous Cystadenoma
-Uncommon slow-growing tumor (from duct cells)
-Cystic lesion lined w/mucin-producing cells
-the cyst ranges in size between 2-20cms
-May have septations

Occur most frequently in middle-aged women
60% in the tail, 5% in the head

Benign tumor w/definite malignant potential
65% 5yr survival rate
Term
Macrocystic Adenoma US
Definition
US Appearance:
Findings:
>2cm
Predominately cystic mass w/solid components
Term
Adenocarcinoma
Definition
-95% of malignant pancreatic tumors
-may originate in ductal cells or in acinar cells
-Location:
Panc head: 60-70%
Panc body: 20-30 %
Panc tail: 5-10%

-Symptoms: Weight loss, Malaise & weakness, N/V
In head:
CBD obstruction
In body/tail:
Larger mass
SV obstruction

Progression:
Spreads to peripancreatic nodes & liver
Treatment:
Surgical options: Whipple’s procedure/ bypass surgery; Non surgical approach (Percutaneous biopsy or Stent/percutaneous biliary drainage)
Prognosis:
8% 1 yr survival rate
<2% 5yr survival rate
4th most common death of cancer (lung, bowel, breast)
Term
Adenocarcinoma US
Definition
US Appearance:
Findings:
Discrete, localized lesion
Hypoechoic texture (compared to the pancreas)
Irregular borders
Dilatation of the CBD
Dilatation of PD (double duct sign)
Nodal/liver mets
Signs of PHT
Ascites
Hypoechoic mass in the peripancreatic area is not always a pancreatic tumor (could be mass of duodenum or lymphadenopathy)
Primary mass invades; lymphadenopathy compresses CBD
When evaluating a mass in this area, important to do:
Demonstrate relationship to pancreas/IVC
Demonstrate signs of obstruction
Term
Pancreas - Endocrine Tumors
Definition
-aka Islet Cell Tumors
-Part of MEN Syndrome (multiple endocrine neoplasia)

Categories:
-Functional (2/3 islet cell tumors)
-Non-functional (1/3 islet cell tumors)
---Larger, in head, 92% malignant

Types of Islet Cell Tumors:
Insulinoma
Gastronoma
Glucagonoma
Term
Insulinoma
Definition
Description:
Most common islet cell tumor
Causes hypersecretion of insulin such that the insulin levels in the blood will remain high even after the blood sugar levels are low (pt will be hypoglycemic)
Most tumors are small (<2cm)
May be benign or malignant
More frequent in body & tail
Malignant tumor is slow-growing
Term
Gastronoma
Definition
Description:
2nd most common islet cell tumor
Arises from pancreas (may involve duodenum)
Tumor produces excessive gastrin
Gastrin causes the stomach to produce excessive amounts of hydrochloric acid, causing ulcers
Have malignant potential
Symptoms:
Zollinger-Ellison Syndrome(abd pain, N/V, weight loss)
Ulcers/ diarrhea
Term
Glucagonoma
Definition
Description:
Rare islet cell tumor
High incidence of malignancy
Term
Metastatic Disease to Pancreas
Definition
Description:
Rare (3% of pancreatic tumors)
Spreads usually by direct extension
Most frequent sources:
Lung
Melanoma
Non-hodgkins lymphoma
Term
Normal Bowel Wall
Definition
Classic Sign “Bull’s Eye” - in cross section
The gut is a continuous hollow tube with 4 layers: (inner to outer)
-Mucosa – inner consists of epithelial lining, loose connective tissue or lamina propria and muscularis mucosa
-Submucosa
-Muscularis propria
-Serosa (adventitia) - outer
Term
Bowel US
Definition
May visualize up to 5 layers on US (inner to outer)
Mucosa: Hyperechoic
Muscularis mucosa or Intramural: Hypoechoic
Submucosa: Hyperechoic
Muscularis Propria: Hypoechoic
Serosa Interface: Hyperechoic
Term
How to Evaluate Bowel Tumors with Ultrasound
Definition
Prep:
Abdomen: best if patient is NPO. Scan entire abdomen
Pelvis: full and empty bladder (bladder can help visualize some masses or displace mass making it more difficult)
Curved linear transducer
Highest frequency possible with adequate penetration
Variable patient position

Compression Sonography is performed
Slow graded pressure is applied
Look for obvious masses or gut signature
Normal gut will be compressed & gas pockets displaced
Thickened abnormal loops of bowel will remain unchanged
Term
Abdomen - GI Tract US
Definition
-Target pattern or pseudokidney = thickened gut wall
-Hypoechoic external rim corresponds to thickened gut wall
-Echogenic center relates to residual gut lumen or mucosal ulceration
-90% of pts with target sign have pathologically significant lesion
-Benign thickened gut wall – Crohn’s disease (most common)
-Malignant thickened wall – adenocarcinoma of the stomach or colon
-Lymphadenopathy & hyperemia of the thickened gut wall are seen with malignant & benign gut wall thickening
Term
GI Tract Doppler
Definition
-Normal gut= little color Doppler signal. Difficult in normal, mobile bowel loops

-Hypervascular= seen with neoplasms, inflammatory disease

-Hypovascular= seen with ischemic & edematous gut
Term
Gut Wall Masses
Definition
Gut wall masses (tumors) with or without ulceration are distinct from a thickened gut wall.

3 types:
Intraluminal: Polyp or mass projecting into the bowel lumen, Hypoechoic mass within bowel lumen, Bowel wall seen around mass


Mural (Annular): Mass causes concentric bowel wall thickening, “Apple Core” lesion on X-ray, Target or Pseudo kidney pattern (Tumor produces thick circumferential hypoechoic rim & Lumen / mucosal lining produces hyperechoic center)

Exophytic: mass on side of bowel wall extending outward, Hypoechoic mass adjacent to bowel wall, May only see mass (no bowel image)
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