2.7.1. Imaging Arthritis Flashcards
Most common imaging for arthritis
plain ol x ray
What arthritic structures are more easily seen with Ultrasound?
can see pannus formation and bursitis in joints with ultrasound
What is an MRI good for as far as imaging for arthritis?
MRI is good for showing internal abnormalities that are second to arthritis (ex. rotator cuff injury in someone with Rheumatoid Arthritis)
Six Pillars of Rheumatology
Arthritis vs. arthralgia
Pattern - adaptive, palindromic, migratory
Chronic vs. acute
Number of joints/which joints
Symmetric vs. asymmetric
Inflammatory vs. noninflammatory
What is secondary arthritis?
Secondary arthritis is due to an injury, trauma, infection, etc that is only located at that joint (not a diffuse phenomenon)
Yellow arrow = normal cartilage
Blue arrow = no cartilage (asymmetric)
Purple arrow = subchondral sclerosis (purple material)
Green arrow = subchondral cys
What can you see/what should you look for on RADIOGRAPHS of noninflammatory osteoarthritis?
Asymmetric joint space narrowing (predominates in weight-bearing joints)
Subchondral sclerosis
Subchondral cyst formation
Osteophyte formation
What is this and what does it indicate?
Yellow arrow = joint space narrowing
Blue arrow = osteophyte formation
Green arrow = subchondral cyst
Look at the following picture. Which one is normal/abnormal? What do you notice about the abnormal knee?
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.
What stage of osteoarthritis is this? Early? Late? How do you know?
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)
Rheumatoid Arthritis - What will you see on images?
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)
What is the abnormality of the following image?
This is a cortical erosion in a patient with early RA. You have to look very closely at the radiographs to find these.
What has happened here?
You can see periarticular osteopenia, where calcium has leached out of the bone. (Darker circled areas)
What is this?
shows the classic “swan neck” deformity of RA
Seronegative spondyloarthropathies - What will you see on imaging?
Multiple erosions, especially at the margins
Bone production (“whiskering”)
Diffuse uniform joint space loss
What’s going on here? What is this a sign of?
Note the erosion (blue arrow) and also the bone production (green arrow) Psoriatic arthritis:
What is this and what does it mean?
Late stage psoriatic arthritis can result in the “pencil in cup” deformity, where some bones have been worn away (arrows):
Reactive arthritis - What does it look like on radiographs?
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
Gout - What should I look for on radiographs?
Tophus
Nonaggressive erosions with overhanging edges
What is this?
The tophus is shown in the image.
What is this picture?
Sclerotic borders (circled) with overhanging edge (arrow) - typical of gout
CPPD - What should I look for on radiographs?
Chondrocalcinosis
Osteoarthritis-like changes in unusual joints
What is this?!
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)
Why would this image make us think of CPPD over OA?
Another unusual place for OA - the wrist - should make you think CPPD:
Septic Arthritis - What should I look for?
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
What is the difference between these two radiographs and what could have caused this?
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
What is this image showing?
Another late finding of septic arthritis is periarticular erosions (yellow arrow)
What is this? What causes it?
Advanced cases of septic arthritis can cause periosteal reaction, which indicates osteomyelitis
