Chapter 7: Introduction to Radiology VII

What are Etiologies for abdominal pain in which you would order an abdominal x-ray as part of the initial work up/evaluation?

1. SBO or LBO

2. constipation

3. stones (kidney, gallstones)

4. bowel perforation

5. hepatomegaly (stretching of capsule) or splenomegaly

6. appendicitis

7. volvulus

How to evaluate a patient for free air (perforation)?

must order

1. flat and upright views

or

2. flat and lateral decubitus views

What does not R/O free air?

1. a flat plate

or

2. KUB view

Why can't a flat plate or KUB view abdominal x-ray not r/o free air?

x-ray beam goes right through and only able to see the fluid line and unable to see air

What is the most sensitive study when looking for free air?

upright view

Etiologies of extra-luminal gas?

1. ruptured hollow viscous

- intestine or stomach

- trauma

- cancer

- enteritis

2. intra-abdominal abscess

- gas produced by bacteria

3. pneumatosis intestinalis

- rupture of blebs in intestine

What is Rigler's sign?

bowel wall visualized on both sides due to intra and extraluminal air

- usually large amount of free air

Rigler's sign may be confused with...

overlapping loops of bowel

- confirm w/ upright view

What is Pneumoretroperitoneum?

1. free air in retroperitoneal space

2. air surrounds lateral border of the R kidney

What is the view to confirm Pneumoretroperitoneum?

erect and decubitus view to see if the gas moves

- if gas is seen to move, it is not in the retroperitoneum

What is the triangle sign?

refers to small triangles of free gas that can typically be positioned between the large bowel and the flank

What is Necrotizing enterocolitis?

intramural gas

Views for necrotizing enterocolitis?

1. supine

2. lateral decubitus

Supine view of necrotizing enterocolitis?

1. bowel is mildly dilated w/ gas mainly on L side

2. bubbly pattern of gas seen in RLQ

Lateral decubitus view of necrotizing enterocolitis?

free intraperitoneal gas present anteriorly

What is the Continuous diaphragm sign?

sufficient free air in L and R hemidiaphragm appear continuous

Etiologies of "too much gas?"

adynamic ileus (bowel stops contracting) including

1. postoperative/posttraumatic

2. inflammatory

- colitis

- pancreatitis

3. sepsis

4. metabolic abnormality

- hyperkalemia

- uremia

- DKA

5. medications

- narcotics (constipation, respiratory depression)

6. bed rest

- decreased bowel movement

Small bowel on imaging studies?

1. look for valvulae conniventes

2. regularly spaced

3. thin mucosal folds that go across the entire lumen

Large bowel on imaging studies?

1. look for haustral folds

2. transverse bands that do not extend across the lumen

Step ladder appearance...

loops arrange themselves from LUQ or RLQ in distal SBO

- check for varices before NG tube

Large bowel obstruction...

1. bowel loops tend not to overlap therefore possible to identify site of obstruction

2. little or no gas in SB if ileocaecal valve remain competent

3. stretched out haustral folds (absent)

Incompetent ileocaecal valve...

decompresses into small bowel and may look like SBO

What is Thumbprinting sign seen in?

any type of ischemic bowel process

Describe thumbprinting.

1. distance between loops of bowel is increased due to thickening of the bowel wall

2. haustral folds very thick (leads to thumbprinting)

Etiologies of minimal abdominal gas?

1. intra-abdominal tumor

2. enlarged abdominal organs

3. intestines filled w/ fluid

4. gastroenteritis

5. poor swallowing (usually a neuro deficit)