Imaging-Arthritis Flashcards
Why do sclerosis and buttressing occur in osteoarthritis?
The joint is compensating for lost cartilage and bone growth on weight bearing portions of the bone.
What are the key characteristics of osteoarthritis you look for on a plain radiograph?
Subchondral sclerosis (dense), cysts (radiolucent), osteophytes and narrowing joint space.
Which hip is normal?
The one on the left. Notice on the right, there is narrowing of the superior joint space, a subchondral cyst on the superior portion of the femoral head and osteophyte formation on the lateral portion of the actabulum.
Where are the osteophytes in this image?
At most of the DIP and intermediate phalangeal joint spaces
Which knee is normal?
The one on the right. Notice on the left joint space loss, osteophyte (shown below) and subchondral sclerosis (radio dense).
Why would you have a patient stand while taking an x-ray of their knee as opposed to lying down when determining if the joint is arthritic?
Weight-bearing will allow you to see joint space loss.
What joints are most common affected by osteoarthritis?
Knees (medial), hips (superior), spine and hands (DIP, PIP, and CMCs)
What is the diagnosis if this patient is only 35 years old?
Secondary osteoarthritis to trauma
What tips you off to this patient having rheumatoid arthritis?
There is an erosion without a sclerotic cap of bone. There is also joint space narrowing.
Where is osteocytopenia often found around joints of patients with rheumatoid arthritis? What other feature often surrounds these joints that can be seen on a radiograph and noted during physical exam?
Metacarpalphalangeal joints and in the wrist. You would also find soft-tissue swelling in the image and in the physical exam.
What are the deformities that you often see in late stage rheumatoid arthritis?
Swan neck (extension of PIP and flexion of DIP seen on left ring finger), Boutonniere (flexion of PIP and hyperextension of DIP on right pinky), Subluxations (ulnar deviation) and Ankylosis (second picture).
What type of arthritis would you diagnose this person with?
Rheumatoid arthritis. It is the only one that demonstrates arthritic change (subluxation seen here) in the cervical spine.
How do you determine if a darker spot on an ultrasound of a joint is synovial fluid or an effusion?
Synovial fluid will not be entirely black and an effusion will be. Also, the black fluid will be compressible where the synovitis will not be compressible.
What joints are commonly involved in rheumatoid arthritis?
Hand (PIP, MCPs and carpal bones), the tarsus bones in the feet, hips, knees, shoulder and c-spine
What is the main difference between inflammatory vs. non-inflammatory arthritis imaging?
Osteophytes = non-inflammatory. Erosions = inflammatory
How do the areas indicated by the arrows guide you in your diagnosis of arthritis in this patient?
They have an erosion (top arrow) which indicates inflammatory arthritis and bone production (bottom arrow) which indicates a seronegative arthropathy. This patient has psoriatic arthritis.
What about these images are signature symptoms of psoriatic arthritis?
Diffuse soft tissue swelling along the whole ray of the finger. (Sausage fingers). And erosions on the distal portion of the bone creating the pencil-in-cup appearance.
A 45 year old male presents with acute pain in this joint of the big toe. His radiograph is seen below. What is happening at the margins of the lesion seen below?
Non-aggressive erosions occur from the tophus in gout. These erosions will have a sclerotic border lining the tophus with an overhanging edge…classic gout image.
What about CPPD deposition disease is different from gout?
They don’t have tophi deposition. They have calcification of cartilage and menisci, a condition called chondrocalcinosis.
In CPPD, you often see joint narrowing and sclerosis. How do you differentiate these patients from those with osteoarthritis?
You see these changes in unusual joints (wrist as seen below) and in non-weight-bearing places
What is the best way to quickly diagnose someone with suspect septic arthritis?
Looking for joint effusions with ultrasound (normal hip on left and swollen hip joint on right). You then have to do needle aspiration and culture of the synovium looking for microbes.
What things would you find on a radiograph of someone with septic arthritis?
Diffuse joint space narrowing, subchondral sclerosis, periarticular erosions, periosteal reaction (osteomyelitis seen below), soft tissue swelling.
What are really late findings of septic arthritis?
Secondary osteoarthritis, joint collapse and joint destruction
