Ch.13 - Recognizing the Normal Abdomen: Conventional Radiographs

Question 1

Air is normally present:

Answer 1

1. Stomach.
2. Colon - Especially rectosigmoid.
3. A small amount of air (2-3 loops) may be seen in normal small bowel.

Question 2

An air-fluid level level is found normally in:

Answer 2

1. Stomach.
2. 2-3 air-fluid levels may be seen in non dilated small bowel.
3. Usually no fluid is visible in the colon.

Question 3

An acute abdominal series usually consists of:

Answer 3

1. Supine abdomen.
2. Prone abdomen (or its substitute, a lateral rectum view).
3. Upright abdomen (or its substitute, a left lateral decubitus view).
4. Upright chest (or its substitute, a supine chest).

Question 4

Supine view of the abdomen:

Answer 4

1. The general scout view for the bowel gas pattern.

2. Useful for seeing calcification and detecting organomegaly or soft tissue masses.

Question 5

The prone view:

Answer 5

Allows air, if present, to be seen in the rectosigmoid, which is important in the evaluation of mechanical obstruction of the bowel.

Question 6

Upright abdomen may demostrate:

Answer 6

Air-fluid levels in the bowel or free intraperitoneal air.

Question 7

The upright chest radiograph may demonstrate:

Answer 7

1. Free air beneath the diaphragm.
2. Pleural effusion (which may provide a clue as to the presence and the nature of intraabdominal pathology).
3. Pneumonia - Which can mimic an acute abdomen.

Question 8

Assessment of organomegaly/soft tissue masses:

Answer 8

CT/MRI/US have essentially replaced conventional radiography in the assessment of organomegaly or soft tissue masses.

Question 9

Recognizing the normal abdomen - What to look for:

Answer 9

1. Gas pattern.
2. Extraluminal air.
3. Calcifications.
4. Soft tissue masses.

Question 10

Normal distribution of gas and fluid in the abdomen:

Answer 10

Stomach –> Normally gas –> Normally air-fluid levels.
Small bowel –> Normally gas (2-3 loops) –> Normally air-fluid levels.
Large bowel –> Normally gas (esp. rectosigmoid) –> NO AIR-FLUID levels.

Question 11

Acute abdominal series - Supine abdomen - Look for:

Answer 11

1. Bowel gas pattern.
2. Calcifications
3. Masses.

Question 12

Acute abdominal series - Prone abdomen - Look for:

Answer 12

Gas in the rectosigmoid.

Question 13

Acute abdominal series - Upright abdomen - Look for:

Answer 13

1. Free air.

2. Air-fluid levels in the bowel.

Question 14

Acute abdominal series - Upright chest - Look for:

Answer 14

1. Free air.
2. Pneumonia.
3. Pleural effusions.

Question 15

To see an air-fluid on conventional radiographs, you must have:

Answer 15

1. Air.
2. Fluid.
3. A horizontal x-ray beam (parallel to the plane of the floor).
4. Air-fluid interfaces cannot be visualized on conventional radiographs taken with a vertical x-ray beam.

Question 16

Abdomen - Conventional radiograph - What to look for?

Answer 16

1. Overall gas pattern.
2. Extraluminal air.
3. Abnormal calcifications.
4. Soft tissue masses.

Question 17

Important point when looking a conventional radiograph of the abdomen?

Answer 17

You are looking for the overall pattern, so don’t spend too much time trying to identify every bubble of bowel gas you see.

Question 18

Virtually, all gas in the bowel comes from …?

Answer 18

Shallowed air. Only a fraction comes from the bacterial fermentation of food.

Question 19

There is almost always air in the stomach, UNLESS?

Answer 19

1. The patient has recently vomited.

2. There is a nasogastric tube in the stomach and the tube is attached to suction.

Question 20

The normal diameter of small bowel is less than?

Answer 20

2.5cm.

Question 21

Large bowel - There is almost always air in the …?

Answer 21

Rectum + Sigmoid. Varying amounts in the remainder of the colon.

Question 22

Stool is recognizable by …?

Answer 22

The multiple, small bubbles of gas present within a semisolid-appearing mass.

Question 23

Aeophagia?

Answer 23

Individuals who shallow large quantities of air.

Question 24

Aerophagia is characterized by?

Answer 24

Numerous polygonal-shaped, air-containing loops of bowel, none of which is dilated.

Question 25

Stomach - Do we see fluid inside the stomach?

Answer 25

Yes - An air-fluid level is almost always demonstrated in the stomach.

Question 26

How many air-fluid levels may be NORMALLY seen in small bowel?

Answer 26

2 or 3 air-fluid levels.

Question 27

Air-fluid levels in colon?

Answer 27

NONE very few.

Question 28

Many air-fluid levels may be present in the colon, if the patient ...?

Answer 28

Has had a recent enema or if the patient is taking medication with a strong anticholinergic, antiperistaltic effect.

Question 29

Depending on the amount of ... around visceral organs, their outlines may be partially visible on conventional radiographs.

Answer 29

FAT --> Example is the psoas muscle which is surrounded by fat.

Question 30

Differentiating large bowel from small bowel - Recognizing large bowel?

Answer 30

1. Peripherally placed. 2. Haustral markings usually DO NOT extend completely across the large bowel from one wall to the other. 3. If they do connect one wall with another, haustral markings are spaced more widely apart than the valvulae conniventes of the small bowel.

Question 31

Differentiating large from small bowel - Recognizing small bowel?

Answer 31

1. Small bowel is centrally placed in the abdomen. 2. Valvulae markings typically extend across the lumen of small bowel from one wall to the other. 3. Valvulae are spaced much closer together than the haustra of the large bowel. 4. Small bowel can achieve a max diameter, even when dilated, of about 5cm. 5. Large bowel can dilate to many times that size.

Question 32

Normal PRONE abdomen?

Answer 32

AIR in the ascending and descending colon + rectosigmoid.

Question 33

There are 2 things to look for on an upright view of the abdomen?

Answer 33

1. Air-fluid levels. | 2. Free intraperitoneal air.

Question 34

Acute abdominal series - What it may contain?

Answer 34

1. Supine view - Almost always. 2. Prone or lateral rectum view. 3. Upright or left-side down (left lateral) decubitus view - One or the other is almost always included. 4. Chest - Upright or supine view.

Question 35

Acute abdominal series - Supine abdomen - Look for?

Answer 35

1. Bowel gas pattern. 2. Calcifications. 3. Masses.

Question 36

Acute abdominal series - Prone abdomen - Look for?

Answer 36

Gas in the rectosigmoid.

Question 37

Acute abdominal series - Upright abdomen - Look for?

Answer 37

1. Free air. | 2. Air-fluid levels in the bowel.

Question 38

Acute abdominal series - Upright chest - Look for?

Answer 38

1. Free air. 2. Pneumonia. 3. Pleural effusions.

Question 39

Acute abdominal series - Supine view ("Scout Film") - How is it obtained?

Answer 39

Patient lies on his or her back on the x-ray table or stretcher and the x-ray beam is directed vertically downward.

Question 40

Acute abdominal series: Supine View ("Scout film") - Substitute view?

Answer 40

There is really NO OTHER view that substitutes for a supine view of the abdomen. Virtually all patients, regardless of their condition, can tolerate this part of the examination.

Question 41

During the course of a routine rectal examination ...?

Answer 41

Almost NO AIR is introduced into the rectosigmoid during the course of a routine rectal exam.

Question 42

Acute abdominal series - Prone view - Substitute view?

Answer 42

1. Frequently, patients are UNABLE TO LIE PRONE because of their physical condition (eg recent surgery, severe abdominal pain). 2. These can turn on their LEFT SIDE and have a LATERAL VIEW OF THE RECTUM exposed with a VERTICAL BEAM to substitute for the prone radiograph.

Question 43

Pancreatitis may sometimes associated with?

Answer 43

A LEFT pleural effusion.

Question 44

Some ovarian tumors may be associated with?

Answer 44

Right-sided or bilateral pleural effusions.

Question 45

An abscess beneath the right hemidiaphragm ...?

Answer 45

May be associated with a right pleural effusion.

Question 46

2 Abdominal calcifications that should NOT be confused with ABNORMAL calcifications?

Answer 46

1. Phleboliths. | 2. Calcification of the rib cartilages.

Question 47

Phleboliths - What are they?

Answer 47

Small, rounded calcifications that represent calcified venous thrombi that occur with increasing age.

Question 48

Phleboliths - Most often seen in?

Answer 48

The pelvic veins of women.

Question 49

Phleboliths classically have a ...?

Answer 49

Lucent center.

Question 50

The lucent center of the phlebolith ...?

Answer 50

Helps differentiate them from ureteral calculi with which phleboliths can be confused.

Question 51

Calcified cartilages tend to have what appearance?

Answer 51

An amorphous, speckled appearance.

Question 52

Conventional radiographic evaluation of soft tissue structures in the abdomen is ...?

Answer 52

LIMITED - Because these structures are soft tissue densities + they are surrounded by other soft tissues of fluid of similar density.

Question 53

2 fundamental ways of recognizing the presence and estimating the size of soft tissue masses or organs on conventional radiographs of the abdomen:

Answer 53

1. Direct visualization of the edges of the structure --> Can ONLY occur if it is surrounded by something of different density than soft tissue, like FAT or FREE AIR. 2. INDIRECT evidence of the mass or enlarged visceral organ by recognizing pathologic displacement of air-filled loops of bowel.

Question 54

Normal liver in conventional radiograph:

Answer 54

1. Normally displaces ALL bowel gas from RUQ. | 2. Tongue-like projection of the right lobe --> RIEDEL.

Question 55

Enlarged liver in conventional radiographs:

Answer 55

1. Might be suggested from conventional radiographs if there is displacement of all bowel from the right upper quadrant down to the iliac crest + across the midline. 2. Notoriously POOR for estimating size of the liver.

Question 56

Enlarged spleen?

Answer 56

If the spleen projects well below the 12th posterior rib OR displaces the stomach BUBBLE toward or across the MIDLINE --> Spleen is probably enlarged.

Question 57

The portions of the kidney outlines may be visible on conventional radiographs if ...?

Answer 57

There is an adequate amount of perirenal FAT present.

Question 58

The kidney length is approx. ?

Answer 58

The height of 4 lumbar vertebral bodies or about 10 to 14cm in size in an adult.

Question 59

The left kidney is roughly the same length as the ...?

Answer 59

Spleen.

Question 60

The urinary bladder is about the size of a ... when CONTRACTED.

Answer 60

LEMON

Question 61

Bladder enlargement is usually recognized by ...?

Answer 61

Displacement of bowel out of the pelvis by a soft tissue mass.

Question 62

Normal uterus dimensions:

Answer 62

4x6x98.

Question 63

... is the best tool for evaluating the size of the uterus and ovaries.

Answer 63

US.

Question 64

The key to differentiating enlarged uterus from a distended bladder is ...?

Answer 64

Identification of the LUCENCY between the bladder + the uterus --> When the uterus is enlarged, the FAT PLANE will be present. When the bladder is dilated, the FAT PLANE will NOT be visible.

Question 65

Psoas muscle?

Answer 65

One or both of them may be visible if there is adequate EXTRAPERITONEAL FAT.

Question 66

Evaluation of the abdomen should focus on 4 main areas:

Answer 66

1. Gas pattern. 2. Free air. 3. Soft tissue masses/Organomegaly. 4. Abnormal calcifications.