Sectional Anatomy

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Sectional Anatomy

• Pancreas

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Technique

• When scanning the pancreas - to ensure an empty
  stomach, the patient should fast 6-8 hours prior
  to exam.
• 5 MHz - 3.5 MHz
• The 2nd portion of the duodenum lies inferior
  lateral to the pancreatic head
• CBD IVC lie posterior lateral to the
  pancreatic head
• Aorta lies posterior

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Pancreas

• Pancreas is divided into
• Uncinate process - posterior medial portion of
  the head
• Head - surrounded by duodenum laterally
• Neck - anterior to the SMA
• Body - lies posterior to stomach
• Tail - ends near the splenic hilium

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Pancreas
Head
Body
Tail
Uncinate Process
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Pancreas Anatomy

• A non-encapsulated Retroperitoneal structure
• It has been described as J-shaped gland, sausage,
  dubm-bell, and tadpole shaped tapering from head
  to tail
• Pancreatic measurements may be misleading
• Symmetry contour is an important
• The AP measurement should not exceed 3 cm
  length is approximately 15-20 cm
• Head - 2.5 cm
• Body - 2.0 cm
• Tail - 2.0 cm
• Duct - lt 2-3 mm

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Size Shape

• It should have a smooth contour regardless of age
  
• Because it is nonencapsulated it blends in with
  he peri-pancreatic fat, thus it may be difficult
  to outline measure
• It is hyperechoic compared to the liver

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Pancreas
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Texture

• The pancreas has a fine homogeneous texture
• Because it is not encapsulated it has limited
  definition sonographicly
• The echogenicity of the pancreas varies depending
  on the fat content
• In children and young adults the pancreas will
  appear less echogenic compared to the liver, with
  a medium-level echogenicity
• In older adults and obese patients the pancreas
  will appear more echogenic compared to the liver

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Pancreas
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Pancreas
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• Pancreas

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Physiology

• Pancreas is a glandular structure with both
  endocrine and exocrine functions
• The exocrine system is composed of acinar cells -
  which makes of 99 of the mass
• Acinar cells secrete pancreatic juice, these
  cells are connected by ducts that converge into
  the main duct of wirsung
• Amylase - digests carbohydrates
• Lipase - digests fats
• Trypsin -digests proteins

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Physiology

• Endocrine system is composed of pancreastic
  islets of langerhans - these cells compose 1 of
  the main pancreatic mass
• Endocrine system secrete insulin, glucagon and
  somatostatin
• Insulin - lowers blood sugar
• Glucagon - increases blood glucose levels by
  stimulating the breakdown of glycogen and the
  release of glucose stored in the liver
• Somatostatin - suppresses insulin/glucagon release

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Pancreas Anatomy

• The pancreas extends from the hilium of the
  spleen to the stomach
• It is found posterior to the stomach
• The pancreas has a variable lie, but it usually
  is oblique with the head at a more inferior level
  than the tail
• SMA - posterior - midline, surrounded by
  mesenteric fat which makes it easy to visualize

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Pancreas
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Pancreas
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Landmarks
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Pancreas
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Landmark

• GDA - a branch off the CHA it descends inferiorly
  along the anterior lateral aspect of the head, it
  marks the anterior right side of the pancreatic
  neck
• CBD - is at the posterior lateral aspect of the
  head, it marks the posterior right side of the
  pancreatic head

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Landmarks
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Pancreas Anatomy

• Pancreatic secretions exit the pancreas via two
  ducts that secrete into the duodenum
• Duct of Wirsung (pancreatic duct)
• Centrally located in pancreas extends from the
  tail to the head
• Unites with CBD and enters the duodenum
• They enter through an opening called the ampulla
  of vauter or sphincter of oddi

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Ultrasound Findings

• Duct of wirsung can be seen as a double
  reflective echogenic line in the pancreas
• Echogenicity is uniform and increased compared to
  the liver
• Increasing age body fat deposition causes the
  pancreas to become more echogenic atrophic
  making it more difficult to distinguish from the
  surrounding retroperitoneal fat
• In children the pancreas is less echogenic
  compared to the liver

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Pancreatic Duct
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Pancreatic Duct
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Landmarks

• Splenic vein - courses posterior and parallel to
  the body and tail of the pancreas
• Superior mesenteric vein - not typically seen,
  but would be seen anterior to the uncinate
  process
• Portal splenic confluence - the splenic vein
  joins with the SMV posterior to the neck to form
  the portal vein, just before it enters the liver
  at the porta hepatis

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Pancreas
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Pancreas
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Pancreas
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Pancreas (sagittal)
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Landmarks

• Splenic artery - branch of the celiac artery off
  the aorta, it is a tortuous vessel and if it is
  seen, it will be seen along the anterior margin
  of the pancreas

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Pancreas (sagittal)
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Landmarks
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Landmarks (sagittal)
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Pancreas
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Pancreas
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Lab Values - Amylase

• This enzyme is essential in the digestion of
  starches
• Whenever there is an obstruction of the
  pancreatic duct or necrosis of the pancreatic
  tissue, the pancreatic enzymes leak into the body
  tissue, spaces into the blood stream
• Blood amylase increases within 24 hours, lasting
  1-3 days then starts to decrease

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Lab Values - Amylase

• Urinary Amylase
• Generally parallels levels found in the blood
• Urinary levels of amylase return to normal more
  slowly
• Remains elevated for 7-10 days
• Increases with acute chronic pancreatitis

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Lab Values - Lipase

• Lipase
• Acinar cells of pancreas produce lipase
• Assesses damage to the pancreas
• Found in the blood and increases with acute
  chronic pancreatitis, pancreatic CA pseudocysts
• Decreases with viral hepatitis

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Lab Values - Glucose

• Glucose testing measures the amount of sugar
  (glucose) in the blood and detects disorders of
  glucose metabolism
• Increases with diabetes, chronic liver disease
  and chronic pancreatitis
• Decreases with islet langerhans tumors and
  hypoglycemia

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Lab Values - Bilirubin

• Obstruction of bile ducts limits bilirubins path
  into duodenum resulting in elevated blood levels
• Increases with carcinoma of the head of the
  pancreas and common duct stones

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Lab Values - Alkaline Phosphatase

• Obstruction of bile ducts
• Increases with carcinoma of the head of the
  pancreas and common duct stones

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Lab Values

• Where ever there is an obstruction of the
  pancreatic duct or necrosis of pancreatic tissue
  - pancreatic enzymes leak into the body tissue
  spaces and into blood stream
• Increases in serum urinary amylase and lipase are
  manifestations of acute pancreatitis

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MRI of the Pancreas
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MRI of the Pancreas
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MRI of the Pancreas