2.7.1. Imaging Arthritis

Question 1

Most common imaging for arthritis

Answer 1

plain ol x ray

Question 2

What arthritic structures are more easily seen with Ultrasound?

Answer 2

can see pannus formation and bursitis in joints with ultrasound

Question 3

What is an MRI good for as far as imaging for arthritis?

Answer 3

MRI is good for showing internal abnormalities that are second to arthritis (ex. rotator cuff injury in someone with Rheumatoid Arthritis)

Question 4

Six Pillars of Rheumatology

Answer 4

Arthritis vs. arthralgia

Pattern - adaptive, palindromic, migratory

Chronic vs. acute

Number of joints/which joints

Symmetric vs. asymmetric

Inflammatory vs. noninflammatory

Question 5

What is secondary arthritis?

Answer 5

Secondary arthritis is due to an injury, trauma, infection, etc that is only located at that joint (not a diffuse phenomenon)

Answer 6

Yellow arrow = normal cartilage

Blue arrow = no cartilage (asymmetric)

Purple arrow = subchondral sclerosis (purple material)

Green arrow = subchondral cys

Question 7

What can you see/what should you look for on RADIOGRAPHS of noninflammatory osteoarthritis?

Answer 7

Asymmetric joint space narrowing (predominates in weight-bearing joints)

Subchondral sclerosis

Subchondral cyst formation

Osteophyte formation

Question 8

What is this and what does it indicate?

Answer 8

Yellow arrow = joint space narrowing

Blue arrow = osteophyte formation

Green arrow = subchondral cyst

Question 9

Look at the following picture. Which one is normal/abnormal? What do you notice about the abnormal knee?

Answer 9

The knee on the left is abnormal. You can see narrowing of the joint space and osteophyte formation. This is a pretty advanced osteoarthritic knee. Compare to the knee on the right, which has symmetric joint space.

Question 10

What stage of osteoarthritis is this? Early? Late? How do you know?

Answer 10

Random knee fact: The patellofemoral joint is the last joint to be affected in osteoarthritis of the knee. You know this is a pretty advanced arthritis. (The picture shows an osteophyte formation in the patellofemoral joint)

Question 11

Rheumatoid Arthritis - What will you see on images?

Answer 11

Primarily synovial inflammation; cartilage destruction is secondary

Diffuse joint space narrowing

Cortical erosions

Sometimes, osteopenia due to increased blood flow (blood flow leaches Ca2+ out of the bone)

Soft tissue swelling (can often see it on radiographs)

Question 12

What is the abnormality of the following image?

Answer 12

This is a cortical erosion in a patient with early RA. You have to look very closely at the radiographs to find these.

Question 13

What has happened here?

Answer 13

You can see periarticular osteopenia, where calcium has leached out of the bone. (Darker circled areas)

Question 14

What is this?

Answer 14

shows the classic “swan neck” deformity of RA

Question 15

Seronegative spondyloarthropathies - What will you see on imaging?

Answer 15

Multiple erosions, especially at the margins

Bone production (“whiskering”)

Diffuse uniform joint space loss

Question 16

What’s going on here? What is this a sign of?

Answer 16

Note the erosion (blue arrow) and also the bone production (green arrow) Psoriatic arthritis:

Question 17

What is this and what does it mean?

Answer 17

Late stage psoriatic arthritis can result in the “pencil in cup” deformity, where some bones have been worn away (arrows):

Question 18

Reactive arthritis - What does it look like on radiographs?

Answer 18

Similar to psoriatic arthritis in appearance, but NOT in distribution. Does NOT occur in hands, but is common in FEET Look for erosion & bone production

Question 19

Gout - What should I look for on radiographs?

Answer 19

Tophus

Nonaggressive erosions with overhanging edges

Question 20

What is this?

Answer 20

The tophus is shown in the image.

Question 21

What is this picture?

Answer 21

Sclerotic borders (circled) with overhanging edge (arrow) - typical of gout

Question 22

CPPD - What should I look for on radiographs?

Answer 22

Chondrocalcinosis

Osteoarthritis-like changes in unusual joints

Question 23

What is this?!

Answer 23

Narrowing of patellofemoral joint

NOTE: Unlike in osteoarthritis (which affects the patella LAST and the medial compartment FIRST), there is NO involvement of the medial or lateral compartments in this figure. (This is unusual, so it should make you think CPPD)

Question 24

Why would this image make us think of CPPD over OA?

Answer 24

Another unusual place for OA - the wrist - should make you think CPPD:

Question 25

Septic Arthritis - What should I look for?

Answer 25

Joint effusion - makes the joint space look wide

Joint space narrowing

Advanced cases

Periarticular erosions

Periosteal reaction (indicates osteomyelitis)

COMPARE with the other side - septic arthritis is monoarthritic - so see what “normal” looks like on the other joint

Question 26

What is the difference between these two radiographs and what could have caused this?

Answer 26

Another early finding of septic arthritis is joint space narrowing: You don’t want to miss this diagnosis. But, if it goes undiagnosed, you can get radiographs that look like the second image

Question 27

What is this image showing?

Answer 27

Another late finding of septic arthritis is periarticular erosions (yellow arrow)

Question 28

What is this? What causes it?

Answer 28

Advanced cases of septic arthritis can cause periosteal reaction, which indicates osteomyelitis