MSK imagin - eval, search, patterns and diagnosis Flashcards
week 3
sensitivity
refers to the proportion of peopele who test postivie among all those who actually have the disease
sensitivity =
true postivie/true positive + false neg
specificity
refers to the proportion of people who test negative among all those who actually do not have that disease
specificity =
true neg/true neg + false positive
alignment of ABCs evaluates for?
genreal skeletal architecture
general contour of bone
alignment of bones to adjacent bones
bone density of ABC’s evaluates for?
genreal bone density
textural abnormalities
local bone density changes
cartilage spaces of ABC’s evaluates for?
joint space width
subchondral bone
epiphyseal plates
soft tissue of ABC’s evaluates for?
- muscles
- fad pads and fat lines
- joint capusles
- periosteum
- misc. soft tissue findings
radiologic comparison of RA and OA:
clinical signs and symptoms
RA: pain, swelling, deforminity, decrease ROM
OA: pain, deformity, decrease ROM
radiologic comparison of RA and OA:
typical distribution
RA: bilateral involvemnt of synovial joints of hands, wrists, feet, hips, knees orelbows or of the atlantoaxial joint
OA: unilateral involvement of synoivial or cartilaginous joints of spine, hihps, knees, first metatarsal and phalanges
radiologic comparison of RA and OA:
alignment
RA: MCP subluxation and ulnar deviation, swan neck and noutonniere deformities of IPs, disloction in alter stages, acetabular protusion at hip
OA: heberdens nodes and DIP, bouchards nodes at PIP, valgus or varous deformities at knees, sublux and joint misalignment
radiologic comparison of RA and OA:
bone density
RA: periartiucalr rarefaction, genrealized osteoprosis in late stages
OA: usually absence of osteoporosis
radiologic comparison of RA and OA:
cartilage spaces
RA: symmetrical, concentric joint space narrowing, subchondral erosions, subchondral cysts
OA: asymmetric, irregular joint space narrowing, sclerotic shbchondral bone, soteophytosis at joint margins, subchondral cysts, intra artiuclar loos bodies
radiologic comparison of RA and OA:
soft tissues
RA: periartiuclar swelling, fusiform swelling
OA: joint effusion, during acute exacerbations
radiologic characteristics of osteoarthritis
- joint space narrowing
- sclerosis of subchondral bone
- osteophyte formation at joint margins
degenerative arthritides and associated conditions
OA
- > Radiographic evidence in all >65
- varies by skeletal region
- spine, hips, knees, first metatarsal, phalanges
- joint space narrowing, osteophytosis, subchondral sclerosis, subchondral, sclerosis
degenerative arthritides and associated conditions
DISH
- > 40
- M >F
- mid to lower thoracic spine, lumbar spine, lower cervical spine
degenerative arthritides and associated conditions:
intervertebral disk herniation
- 25-45
- M > F
- L4-5, C5-6
- decreased disk height, morginal osteophytosis
degenerative arthritides and associated conditions:
spinal stenosis
- 40-50
- M>F
- cervical and lumbar spines
- radiogrpahy of limited value except to evaluate related conditions (spondylolisthesis, pagets disease)
Examples of pathology related to skeletal distribution
category: congenital
monostotic/monoarticular:
- cervical rib
osteoporosis - localized areas of decreased bone density, or rarefaction, appear in the early stages of ?
- rheumatoid arthritis at periarticular regions
- due to increased blood flow of the synovium
osteoporosis - loss of cortical thickness, generalized osteopenia, and associated fractures. the most common sites for fracture are ?
- vertebrae,
- proximal humerus
- distal radius
- proximal femur
what is the Z score for normal bone mineral density?
> -1.0
what is the Z score for osteopenia?
(-1.0 to -2.5)
What is the Z score for osteoporosis
< -2.5
what is this image showing?
degenerative disk disease
what are 3 types of infection of the MSK system?
- bone (osteomyelitis)
- infections of joint (septic or infectious arthritis)
- infections of soft tissues (cellulitis, myositis)
what is the earliest radiographic feature of any infection?
soft tissue swelling
What are some radiologic characteristics of osteomyelitis
- soft tissue swelling 24-48 hrs after onset
- radiolucent lytic lesion in 7-10 days
- sequestra and involucra in 6-8 wks
- draining sinus tracts
What are some radiologic characteristics of infectious or septic arthritis
- soft tissue swelling
- joint effusion
- periartiuclar rarefaction
- joint space narrowing
- subchondral bone erosion
What are some radiologic characteristics of cellulitis
- soft tissue swelling
- radiolucent streaks or bubbles representing gas gangrene
how can bone tumors be categorized?
benign or malignant
further categorized by theri tissue of origin:
- margin of the lesion
- whether the matrix is osteoid, chondroid, or mixed
- type of destruction (geographic, moth-eaten, permeative)
- interrupted or uninterrupted periosteal response
- presence of soft tissue extension of the lesion
