Radiology Flashcards
2 Differential for bilateral symmetrical Sacroilitis
- AS
- IBD associated SpA
2 differentials for b/l asymmetric SI joint involvement
- PsA
- ReA
One DDx for monoarticular SI involvement
Septic
2 DDx for pseudo-sacroilitis
- Hyper PTH, renal OD
- Osteitis ilii condensans
Characteristic feature that distinguishes the SpA class from other inflammatory arthropathies
Enthesitis
Characteristic radio graphic feature that distinguishes PsA from rest of the SpA and inflammatory arthritis
Bone formation - whiskering (fluffy bone formation) and periosteal reaction
Radio graphic features of PsA spondylitis that differential from rest of SpA
- Jug handle bone lesions (they are due to periosteal bone formation taster than syndesmophyte)
- That are chunkier and thick
- Skip levels on the spine
- Usually unilateral (more on the right)
Why do we see marginal erosions in inflammatory arthritis (2 clue words)
- PANNUS attaches at the margins which erodes into the bony structure
- BARE area of the bone - intra-articular bone which is not covered by articular surface for protection.
How do you differentiate between erosion in inflammatory arthritis and other productive arthritis
Erosions with inflammatory arthritis develops faster and therefore LUCENCY around the erosion.
Erosions in productive arthritis developed slowly and therefore SCLEROSIS predominates
5 characteristic radio graphic features of inflammatory arthritis
- Symmetric/uniform JSN
- Marginal erosions — initially
- Central erosions — eventually
- Erosions with lucency
- Periarticular osteopenia
Why do we need flexion and extension views of the spine to look for RA related C-spine involvement?
Looking for ATLANTO-AXIAL INSTABILITY —> tendon laxity can be seen as normal joint space in one view and increased space in another view (mostly flexion)
If you are looking for an inflammatory arthritis, when and what type of MRI should you order? What is the additional information that MRI can give from radiographs?
MRI with and without contrast.
Things that you wouldn’t see in conventional radiographs are:
1. Synovitis
2. Bone marrow edema which suggests inflammatory cells aim BM and is a poor prognostic sign
What are the characteristic radio graphic features along with pathophysiological explanation for AD related spondylitis (name 6)
- CORNER SIGN: seen in MRI —> bone marrow edema at vertebral corners due to Enthesitis at sharpey’s fibers
- SHINY CORNERS: Seen in radiographs due to sclerosis at previous active Enthesitis at sharpey fiber attachment.
- ANDERSON LESION: inflammatory discitis —> Erosions at the vertebral end plate.
- SYNDESMOPHYTES: calcified sharpey’s fibers which start and end at the edge of vertebral bodies. Result in ankylosis.
- TROLLEY SIGN: ankylosis at facet joints seen as parallel lines.
- DAGGER SIGN: ankylosis at spinous processes.
DISH is ossification of —-
ALL
What are the 4 DDx of spondylitis
- SPA
- RA (only facet spondylitis)
- DISH
- OPLL
How will you radiographically distinguish EOA from PSA
PSA: whiskering and periosteal reaction
EOA: osteoohytosis
4 radiographic characteristics of OA
- Asymmetric JSN
- Subchondral sclerosis
- Subchondral cysts —> above three tell degree of damage
- Osteoohytes —> characteristic finding
Characteristic migration pattern of hip joint in OA —> is there difference between male and female?
Characteristic: SUPEROLATERAL
Females can have AXIAL due to pelvic anatomy
What is the other fancy name for weight bearing Knee X-ray
Rosenberg view
Most common appendicular joint involvement in OA
AC joint
Why should we get lateral hand X-rays
Because osteophytois and production bone formation is not well visualized on AP view, specially at DIPs
Can hammertoe deformity occur in OA
Yes
Where do you see chondrocalcinosis in hips
Lateral acetabular margin
Which characteristic hand joints are involved in CPPD
2nd and 3rd MCP (can have a ray pattern)
