PowerPoint 1 Flashcards
What should we know about imaging
Indications
Limitations
Risks
Benefits
What type of imaging should we request
Imaging modality to best illustrate the suspected pathology
Least risk
Reasonable price
If unable to directly order imaging, we can recommend
When should we order imaging
History, review of systems, and objective testing point to a need
Ex ( femoral neck stress fractures, suspected cervical spine fracture)
Failure to progress with treatment
Only order when positive findings will alter intervention
VINDICATE
Vascular Infection Neoplasm Drugs Inflammatory/idiopathic Congenital Autoimmune Trauma Endocrine/metabolic
Considerations for imaging
Acute injuries & x-ray
False positives
False negatives
High level of suspicion
Potential errors in imaging
Poor quality (movement artifact, technical error)
Imaging wrong are (referred pain)
Inappropriate modality
Requesting diagnostic imaging
Order/recommendation
F/B brief statement (mechanism of injury, anatomical area of pathology)
Who interprets the imaging
It’s role in diagnosis is legally for the radiologist
However, we participate in the interpretation
Basis = relationship with MD
What is our role in interpretation of imaging
Indications for imaging
Integrate info from written radiologist report into to plan
Appropriate selection of imaging modality (be familiar with best imaging modality based in suspected pathology)
Area of imaging
Usefulness of viewing imaging for info related to rehab, but not in report
Interaction regarding the interpretation
Conventional radiographs
The standard x-ray
Useful for cortical & trabecular bone
Certain bony reactions associated with infection and neoplasms
Fractures
Radiographs
Low cost
Limitations (scaphoid fracture)
Ionizing radiation (absorbed or dispersed, bone (high density) absorbs more radiation)
Protect reproductive organs
X-ray production four major densities
Air Fat Fluid Bone Plus 1 - metal
Air on x-ray
Most radiolucent
Absorbs least number of particles
Black/darkest portion
Fat on x-ray
- Fat absorbs more of the beam than air or gas but less than the other densities
- Air and fat are considered radiolucent (black on x-ray, greater film exposure because more x-ray energy is transmitted through these medial in the body to the film or cassette)
Fluid on x-ray
- fluiid is of intermediate radiolucency
- More absorbent than air or gas and fat-
Represents the varying densities if soft tissue organs and muscle
Bone in x-rays
- The most dense, naturally occurring substance in the body
- Cortical bone is much denser than cancellous bone
- Radio-opaque
Metal on x-ray
completely radio-opaque
what views should be requested
- depends on suspected injury
- typically minimum of 2 views at righ angles to each other
conventional radiographs: ionizing radiation, what needs protection
thyroid
breast
gonads
reproductive organs
conventional radiographs ionizing radiation: who needs protection
patient
practitioner
conventional radiographs ionizing radiation: limit exposre via
shields
vests
gloves
collars
conventional radiographs limitations
difficulty in detecting early changes
dificulty in viewing soft tissue
conventional radiographs limitations: difficulty in detecting early changes with
neoplasms
infection
fractures
early osteoperosis
interpreting radiographs systematically ABCS
alignment
bones
cartilage
soft tissue
interpreting radiographs systematically: A, Alignment
- continuity of the bones and joint surfaces
- study size, number, shape, and aligment of bones
- e.g fx, dislocation, cortical alterations
interpreting radiographs systematically: B, bones
- uniform color
- areas with decreased density appear darker
- study bone density (general and focal) and trabecular bone alterations
- eg. metabolic bone disease, infection, tumors, arthritic changes
interpreting radiographs systematically: C, cartilage
- joint spaces should be smooth
- study cartilage space (width, symmetry) density of subcondral bone
- eg. degenerative and rheumatic disorders
interpreting radiographs systematically: S, soft tissue
- soft tissue cannot be seen
- swelling within or between soft tissue and bones can be seen
interpreting radiographs systematically: study soft tissue for
- swelling
- capsular distention
- periosteal elevation
- eg. truama, tumors, look for specific signs
- sail sign
stress radiograph
stress is applied to the joint to measure joint laxity
computed tomography (CT) scan
- x-ray source and detectors rotate around the body
- computer determines the density of the tissue
- creates a two-dimensional image (slice)
- allows detailed axial views of entire body
- slice tickness (1-20 mm)
- radiation is not cumulative
- excellent discrimination of tissue density
- images may be reconstructed
computed tomography (CT) scan: combined with contrast
myelogram
arteriogram
arthrogram
