GIT V (Large Bowel)

Question 1

Contrast agent used in barium enema

Answer 1

Diluted Gastrograffin

Question 2

Which better for detection of colorectal cancer and polyps, CTC or barium enema

Answer 2

CTC replaced barium enema

Enema study performed in patients unsuitable or failed colonoscopy

Question 3

Uses of MRI in Large bowel

Answer 3

It is accurate for local staing of Rectal malignancy in addition to assessing bengin disease such as anal fistula and pelvic floor dysfunction

Question 4

MR Colonography

Answer 4

It can be used to evaluate the colonic lumen, colon wall and extra-luminal tissues

Question 5

A dynamic study of the rectal and pelvic floor

Answer 5

MRI proctography

Question 6

Role of USS in large intestine

Answer 6

• It can provide detailed imaging of the colon wall.
• has a valuable role for assessing the extent and activity of IBD
• Dx of appendicitis
• assessment of the anal sphincters

Question 7

Role fo PET in large intestine

Answer 7

Useful for assessment of extra luminal disease and distant metastases.

Question 8

So… what are modalities used in large intestine imaging

Answer 8

AXR
Fluoroscopy
Endoscopic Ultrasound
CT ( And CT colonography & vitusl colonoscopy)
MRI (MR colonography & MRI proctography )
PET scan

Question 9

Causes of LBO

Answer 9

Carcinoma
Diverticulitis
Volvulus
Stricture (Crohn’s)
Fecal impaction
Hernia
Imperforate anus or meconium ileus in pediatric population

Question 10

Large bowel obstruction on plain radiograph:

Answer 10

Colonic distention: gaseous
Collapsed distal colon
Very few or no air-fluid levels are found in the large bowel (bc water is reabsored)

Question 11

In large bowel obstruction, small bowel dilatation is depending on:

Answer 11

Duration of obstruction
Incomplete of the ileoceal valve

Question 12

Stigmata of an ischemic colon (advanced):

Answer 12

Stigmata = 3 gases
Intramural gas (pneumatosis coli)
Portal venous gas.
Free intra-abdominal gas (pneumoperitoneum).

Question 13

The most widely used modality for assessment of large bowel obstruction

Answer 13

CT: can confirm the diagnosis and localize the location of obstruction, able to identify the cause, and complications.

Question 14

Imp
Large vs. Small bowel

Answer 14

Large bowel: peripheral, haustral markings don’t extend from wall to wall, and max diameter 6cm(cecom 9cm)
Smalle bowel: central, plica extend across lumen, maximum diameter of 3cm

Question 15

Most common form of GIT volvulus

Answer 15

Sigmoid volvulus

Question 16

Predisposing factors and peak age of volvulus

Answer 16

Redundant sigmoid colon
Chronic constipation
High-roughage diet (may cause a along, redundant sigmoid

**peak age >50y

Question 17

Radiological findings of sigmoid volvulus

Answer 17

On AXR(diagnostic):
Coffe-bean sign
On Fluoroscopy barium enema:
Bird’s-beak sign

CT scan useful in assessing mural wall ischemia

Question 18

Predisposing factors and peak age for cecal volvulus

Answer 18

10% of GIT volvulus
Freely mobile colon
Adhesion

Peak age : 30-60y

Question 19

Cecal volvulus on AXR:

Answer 19

• Distended cecum and abnormal positioning of the bowel loops.
• A coffee bean sign
• in some cases, signs of bowel ischemia oe necrosis
• Caecal Embryo sign

Question 20

Absence of Auerbach and Meissner plexus along a variable length of the distal GI tract

Answer 20

Hurschsprung’s disease HSD
Or Congenital megacolon