7) Pancreas and peritoneum

Question 1

Define:
Mesentary
Omentum
Visceral peritoneum
Parietal peritoneum

Answer 1

Mesentary: The double fold of peritoneum that attaches the intestines to abdominal wall

Omentum: Connects stomach to other organs

Visceral peritoneum: Is the inner layer of peritoneum

Parietal peritoneum: outer layer adjacent to abdominal wall

Question 2

Pancreas - ductal adenocarcinoma (sign,

Answer 2

• obstructive jaundice from CBD obstruction in 70% of pt’s
• superior mesenteric artery and portal vein must be visible on CT to see if they have been affected. Surgery can be hard/impossible if tumour surrounds these vessels. Tail tumour can be solved with surgery

CT: is choice for diagnosing and staging pancreatic adenocarcinoma

• tumours appear as hypoattenuating mass on C+ CT (arterial phase)
• poorly defined margins
• dilation of proximal pancreatic and bile duct

Question 3

Peritoneal disease signs (PINAP)

Answer 3

Pneumoperitoneum: Free air in peritoneal cavity, abdo pain
Infection: Fluid quantity increases
Neoplasia: Secondary tumour spread can occur (blood, lymphatic)
Ascites: Fluid accumulation in peritoneum
Peritoneal fibrosis: abnormal tissue, retraction of membranes

Question 4

Pneumoperitoneum (cause,

Answer 4

- Often caused by perforated gastric ulcer
Radiographic appearance
- gas over diaphragm
- falciform ligament can be seen
- football sign

Question 5

Peritoneal carcinomatosis (define, routes of dissemination, key signs)

Answer 5

• is the intraperitoneal dissemination of any tumour that does not originate from the peritoneum its self

Routes of dissemination include

• haematogenous
• lymphatic
• peritoneal surface spread

Key signs
- Ascites
- greater omentum involvement
- invasion of mesentery  
tumour implants in serous membrane

Question 6

Mesenteric fibromatosis (CT, MRI)

Answer 6

• usually 5-10cm diameter, maybe as large as 30cm
• well circumscribed

CT: typically appears as round mass with similar attenuation as skeletal mm

T1) low SI
T2) High SI

Question 7

Spleen (normal)

Answer 7

• Non-con CT, spleen parenchyma is homogenous

- In first 45 seconds of IV C+, spleen shows heterogeneous sometimes striped C+ enhancement

Question 8

Spleen enlargement (associated with, can move other abdominal structures how, what is best modality)

Answer 8

• Associated with infections, TB, portal hypertension
• Can elevate diaphragm, displace stomach to midline, displace kidney inferiorly
• CT is Best modality for determining enlargement, can help identify cause