GI imaging

Question 1

types of x-rays

Answer 1

• Plain radiography, or plain x-ray
• Computed Tomography
• Fluoroscopy — which produces moving/live images of an organ
• Mammography
• Angiography

Question 2

a diagnostic test that uses radiation waves to take pictures of your body tissues.

Answer 2

X-ray

Question 3

Different parts of the body absorb the x-rays in varying degrees, describe each

Answer 3

1. Dense bone absorbs much of radiation = Bones appear white
2. Soft tissue, such as muscle, fat, organs, absorb some, but not as much as bones = shades of gray
3. Air does not absorb = black

Question 4

Provides images of the organs in the abdominal cavity, including stomach, liver, intestines, and spleen

Answer 4

Abdominal X-ray

Question 5

When an abdominal x-ray is performed to provide pictures of the kidneys, ureters, bladder, it’s called ?

Answer 5

KUB x-ray
Contrast is used

Question 6

which part of the body has the most radiation when imaged?

Answer 6

CT abdo/pelvis ~14 mSv = 140 cigs

Question 7

gas or air trapped within the peritoneal cavity, but outside the lumen of the bowel.

Answer 7

Free gas, or pneumoperitoneum

Question 8

2 causes of free air under diaphagram

Answer 8

1. bowel perforation
2. insufflation of gas (CO2 or air) during laparoscopy

Question 9

difference between bowel perforation vs insufflation of gas during laparoscopy

Answer 9

• Both these causes have identical X-ray appearances, but very different clinical significance.
• BOWEL PERF IS A SURGICAL EMERGENCY!

Question 10

how to evaluate a suspected Pneumoperitoneum? why?

Answer 10

Upright chest X-ray + standard supine abd X-ray
Allows any free intra-abdominal gas to rise up, forming a crescent beneath the diaphragm. It is said that as little as 1ml of gas can be detected in this way.

Question 11

how does poo appear on imaging

constipation

Answer 11

soft tissue opacities with internal mottled air.

Question 12

how to image for constipation

Answer 12

Anteroposterior (AP) images of the abdomen and pelvis in the supine position
- visualize and qualify the burden of feces
- visualize the size of the colon,
- assess for colonic obstruction.

Question 13

what imaging could you get if you are concern for complications of constipation (free air from perforation)

Answer 13

Erect and lateral decubitus images of the abdomen and pelvis to may be added

Question 14

key radiographic findings of constipation

Answer 14

presence of large fecal burden throughout the colon and a relative paucity or absence of luminal gas.

Question 15

imaging uses sound waves to produce pictures of the inside of the body
When a sound wave strikes an object, it bounces or reflects back, or “echoes”

Answer 15

US

Question 16

By measuring US echo waves, it is possible to determine how far away the object is, as well as:

Answer 16

• Object’s size
• Object’s shape
• Object’s consistency

Question 17

Used to detect changes in the appearance of organs, tissues, and vessels
Also used to detect abnormal masses, such as tumors

Answer 17

Ultrasound

Question 19

what is Echogenicity

Answer 19

the ability to reflect or transmit US waves in the context of surrounding tissues

Whenever there are structures with different echogenicities, a visible difference in contrast will be apparent on screen

Question 20

Tissue in body that is more dense or solid
Absorbs more US waves
Less reflective and low amount of echoes when compared with neighboring structures
Appears gray or darker than surrounding tissue
Made up of muscle/fibrous connective tissue

what type of echo/US

Answer 20

Hypoechoic

Question 21

Reflects sound waves of higher amplitude
Gives off more “echoes”
Appears lighter and brighter than surrounding tissue
Air, fat, gas
Ex: fatty liver would show hyperechoic spots on liver

which type of echo/US

Answer 21

Hyperechoic

Question 22

Structures that appear black
No internal echoes reflecting back
Fluid and blood filled structures because the beam passes easily through these structures without significant reflection.
Sound waves will travel easily through these uniform substances

which type of echo/US

Answer 22

Anechoic

Question 23

how thick is the gallbladder wall?

Answer 23

Smooth, thin walls, < 2 mm

Question 24

what does the biliary tree look like

Answer 24

Narrow caliber - 6mm or less
Uniform ductal walls
Common Bile Duct

Question 25

• Provides a detailed view of the internal organs and structures
• Superior to conventional radiography because of its exquisite contrast resolution - Has 10x increase in contrast resolution
• anatomic structures in different planes are displayed free of superimposition

Answer 25

CT

Question 26

how does a CT work

Answer 26

1. Produces cross-sectional images of the body
   - Each cross-sectional image represents a “slice” of the person being imaged: Coronal-divides ventral/dorsal, Sagittal-divides R/L, Axial-divides horizontal/transverse
2. Several x-ray beams and electronic x-ray detectors rotate around pt.

Question 27

types of contrasts for CT exam

Answer 27

• IV - Best for imaging tumors, vascular abnormalities, urinary tract
• Oral - Best for visualizing bowel lumen, esophagus, stomach
• Non-contrast - Best for evaluating stones

Question 28

Pros vs Cons of CT contrast

Answer 28

1. Pros of contrast - Helps “enhance” CT and are able to see organs/tissues very clearly
   - Delineates between organs
2. Cons
   - May take too long if urgently needed
   - Contrast contraindicated in renal failure
   - Some have allergies to it
   - Can cause flushing and has metallic taste

Question 29

1. Special type of x-ray test
2. Largely replaced by EGD
   - Patients drink barium, images then obtained by fluoroscopy as passes through esophagus
   - Can use for dysphagia
3. Can use for an “upper GI” - drinks barium as the fluoroscopy images pass through stomach into duodenum
4. Upper GI with Small Bowel Follow Through

Answer 29

Barium swallow

Question 30

what is Barium Enema

Answer 30

radiographic (X-ray) examination of the lower gastrointestinal (GI) tract.
made visible on X-ray film by filling colon with barium.
Barium highlights certain areas in the body to create a clearer picture.

Question 31

• Special type of MRI to produce detailed pictures of these ducts and organs
• Powerful magnetic field, radio waves, and a computer to evaluate the liver, gallbladder, bile ducts, pancreas, and pancreatic ducts
• Is noninvasive

Answer 31

Magnetic resonance cholangiopancreatography

Question 32

1. A diagnostic and interventional procedure using both endoscopy and fluoroscopy
   - examination and intervention of biliary tree and pancreatic ducts
2. It involves passing the endoscope to the descending duodenum and injecting contrast through the Ampulla of Vater

Answer 32

Endoscopic retrograde cholangiopancreatography
(ERCP)

Question 33

biggest complication of ERCP?

Answer 33

Pancreatitis

• Prolonged manipulation of papillary orifice, difficult cannulation of the biliary tree, and repeated inadvertent instrumentation of the pancreatic duct result in ductal injury or injury to the ampulla.
• Resultant papillary edema caused by mechanical or thermal injury is thought to obstruct the outflow of pancreatic secretion, resulting in pancreatitis.