Medical Imaging

Question 1

What is a Doppler test?

Answer 1

High freq ultrasound to measure the amount of blood flow through your arteries and veins

Question 2

2 types of interactions occur during X-rays, what are they?

Answer 2

Penetrate and Scatter

Question 3

How does an Ultrasound work?

Answer 3

Putting electric current through a piezoelectric crystal produces sound waves. When the sound waves return, you squeeze the crystal to convert sound to an electric current.

SONAR = Sound Navigation and Ranging

Ultrasonic devices are used to detect objects and measure distances.

Question 4

Faraday cage

Answer 4

MRI uses same bandwidth as ABC radio hence needs to be in a copper lined room to block it out (64 Hz)

Question 5

What can’t ultrasound penetrate through?

Answer 5

Bone, fat and gas

Question 6

Nuclear medicine uses a scintillation crystal - what is it?

Answer 6

Gamma camera

Question 7

What chemicals do we use for different areas?

Answer 7

Bone - phosphonate
Kidney - Mag3
Heart - Sestamibi

Question 8

Thecal sac

Answer 8

The thecal sac or dural sac is the membranous sheath of dura mater that surrounds the spinal cord and the cauda equina. The thecal sac contains the CSF in which the spinal cord ‘floats’.

Question 9

Where does pain from the lumbar spine get referred to?

Answer 9

Buttocks and legs -distributed along sciatic nerve

Question 10

Name 2 methods that are infeffecitive for imaging spinal injuries

Answer 10

US - sound doesn’t penetrate bone

NM - doesn’t give info about pathology

Question 11

LUMBAR VERTEBRA

• Side profile
• Anterior profile

Answer 11

square to rectangular

rectangular with “overhangs”

Question 12

Spondylolisthesis

Answer 12

It is the forward displacement of a vertebra, especially the fifth lumbar vertebra, most commonly occurring after a fracture. Backward displacement is referred to as retrolisthesis
-Facet joints fail & lead to excessive forward movement & compression of nerves

Question 13

Desiccation of nucleus pulposus

Answer 13

Process of extreme drying leads to proteoglycans of nucleus resembling coconut and no longer spongy.

Question 14

What happens due to desiccation of nucleus?

Answer 14

Leads to annular cracks, where defect in the annulus allowing nucleus to squeeze through, causing compression on the nerves.

Question 15

Disc bulge

Answer 15

“grand dad’s underpants” loss of elasticity & weakness of annulus fibrosis

Question 16

Herniation

Answer 16

Protrusion - Focal extension (neck breadth > depth)

Extrusion – more extreme extension (neck breadth

Question 17

Spondylitis (different to Spondylolisthesis)

Answer 17

• Degenerative arthritis of the spine
• Disc desiccation – loss of disc height, secondary arthritis
• Compression of trefoil appearance due to osteophytes growing off vertebral bodies

Question 18

Spinal canal stenosis – What is it & treatment?

Answer 18

Laminectomy - a surgical operation to remove the back of one or more vertebrae, usually to give access to the spinal cord or to relieve pressure on nerves.

-Epidural steroid – cortisone anti-inflammatory drug inserted into epidural space (between bone & thecal sac

Question 19

Knee is 2 shallow symmetrical sockets that are highly constrained

Answer 19

Knee is 2 shallow symmetrical sockets that are highly constrained

Question 20

Radiographic anatomy : ball and socket (concentric rings x 2)
•rings to maintain stability
–similar to shoulder
What are the 5 layers?
Which layers are most prone to wear and tear?

Answer 20

• bones – layer 1
• meniscus – layer 2
• ligaments – layer 3 (most important)
• capsule – layer 4
• tendons – layer 5

Layer 1 and 2 are most prone to wear and tear

Question 21

Segond fracture

Answer 21

Segond fracture is an avulsion fracture of the knee that involves the lateral aspect of the tibial plateau and associated with ACL tear.

Question 22

Would you use X-ray or CT for patients with plasters around their leg? Why?

Answer 22

CT - it is cross sectional where X-ray would make it 3D to 2D

Question 23

Diaphyseal aclasis

Answer 23

An inherited autosomal dominant disorder in which multiple osteochondromas are seen throughout the skeleton - sprouting bits of bone coming off all bones of the body

Question 24

Degenerative osteoarthritis

Answer 24

Wearing away of articular cartilage - leading to bone spurs

Question 25

How to fix articular surface that has worn out?

Answer 25

Knee Arthroplasty - Replacing bone of femoral condyle and tibial plateau with metal that will articulate smoothly. Polyethylene in between the metal (allows for articulation). Lasts 10 to 20 years.

Question 26

What colour are menisci, tendons and lig. in MRI? Water is white on T_

Answer 26

Black - anything without water is black

Water is white on T2

Question 27

IN MRI - What colour is cortical bone? Trabecular bone? Cartilage?

Answer 27

Cortical - black
Trabecular - white (contains bone marrow that is fatty)
Cartilage is grey

Question 28

ACL and PCL do not heal like other ligs. in the knee, hence how do you treat it?

Answer 28

Take a part of the patella or semitendinousus tendon and reconstruct it where the ACL used to be

Question 29

Where does joint effusion occur? How do we look at the joint?

Answer 29

Suprapatellar pouch using an arthogram

An arthrogram is a test using X-rays to obtain a series of pictures of a joint after a contrast material (such as a dye, water, air, or a combination of these) has been injected into the joint

Question 30

Role of patella in relation to patellar tendon

Answer 30

Protects the tendon as it passe over bone and increases its strength.

Question 31

Patellar tendinopathy

Answer 31

Overuse injury affecting your knee. It is the result of your patella tendon being overstressed aka jumper’s knee

Question 32

What happens to patella bone in patellar tendon rupture?

Answer 32

The bone goes up into the thigh