Imaging Introduction Flashcards
Why do we study imaging as PTs?
- Adds to our examination and evaluation (helps us rule out and rule in)
- Assists with intervention
- Contributes to prognosis (Ex: how advanced the arthritis, osteoarthritis, etc. is to help determine pain level explanation)
- Better communication of involved parties
What kind of interventions can imaging help PTs with?
- Motion barriers (ex: bone spurs)
- Weight bearing or functional levels (ex: looking for that bony callus from clinical union)
- Location (ex: bone stimulator - where the fracture is so you know where the bone stimulator goes)
What is “routine radiographing”?
- Typically the first imaging preformed (x-ray)
- Ex: bone break you do an X-ray
What is the major advantage of routine radiographs?
It is the most efficient for INITIAL assessment of bone or joint abnormality
What is the major disadvantage of routine radiographs?
It is limited for complex and subtle bony abnormalities
What are routine radiographs also called?
Commonly referred to as plain films, films or x-rays
How many images are needed and at what degrees when taking an x-ray or a routine radiograph?
At least two images at 90 degrees are needed to view all 3 dimensions
One view is _____ view.
NO
The standardized positions and views of x-rays help with:
- Greatest visualization
- Minimize radiation exposure
- Projection of x-ray beams
What are the options for the projection of x-ray beams?
- Anterior to posterior (AP)
- Posterior to anterior (PA)
- Lateral
- Oblique
Which projection is greater for projection, AP or PA?
Anterior to posterior (AP) > Posterior to anterior (PA)
When x-ray beams enter the body what happens at the tissue level?
X-ray beams are absorbed by the tissues at differing amounts
What color do x-ray beams produce when they enter the body?
Produce shades of gray
Where does the x-ray beam go when it emerges from the body?
Onto an interpretation device or image receptor
What color is air on an x-ray?
Black
What color are fat and bone marrow on an x-ray?
Black/ gray
What color are water; muscle and soft tissue on an x-ray?
Gray
What color is bone on an x-ray?
White
What color are contrast dyes on an x-ray?
Bright white
What color are metals on an x-ray?
Solid white
How are you supposed to view an x-ray that was taken in an AP and PA projection?
As if the patient was facing you and in anatomical position
What body parts are the exception to the viewing rule when looking at AP and PA x-rays?
- Hands and feet are viewed with the toes and the fingers pointing up
- These will be the same as your personal hand or foot
How are you supposed to view an x-ray that was taken in a lateral projection?
In the path of the beam
How many markers should you identify when viewing a radiograph and what are some examples?
- Identify 2 markers
- Projected health information (ex: name)
- Side of the body with R or L (do NOT orient the slide marker to obtain the correct letter position)
What are the ABCS of a radiograph?
- Alignment
- Bone Density
- Cartilage Space
- Soft Tissue
Alignment is seen in what aspect of a radiograph?
- General architecture and anatomy (ex: size, number of bones, etc)
- General Contour (spurs, breaks, markings)
Bone density is described as the contrast between _____ and _____ _____.
Bone and Other Tissue
What are the two kinds of bone contrast?
- Cortical
- Cancellous
Describe cortical bone contrast:
- Outer layer of bone and predominately in appendicular skeleton
- Denser and whiter
Describe cancellous bone contrast:
- Interspersed within marrow and predominantly in axial skeleton
- Less dense and grayer
Bone density helps us see what kind of changes to the bone?
Texture/ local density like sclerotic changes
What are sclerotic changes?
Increased bone density that may be abnormal or normal
With cartilage spaces in x-rays, what are you typically looking for?
- Narrowing
- Subchondral bone sclerosis (body is trying to repair damaged bone) and erosion)
- Epiphyseal plates - position, size, and smooth margin
What are you looking for on an x-ray when it comes to soft tissue?
- Muscle wasting and edema
- Fat pad displacement
- Capsular effusion
What is periosteum and what part of the ABCS is it apart of?
- Bone covering that shows up as a soft tissue shadow
- The “S” - soft tissue
If the periosteum is solid what does this mean?
Indication of a slow growth of healing or infection
If the periosteum is laminated or layered what does this mean?
Indication of repetitive stress
If the periosteum is spiculated (needle like) or pointed what does this mean?
Indiction of breakthrough due to a tumor
What is the Codman’s Triangle?
A raised periosteum with any of the following conditions: Solid, Laminated, Layered, Spiculated, or Pointed
What are other common MSK imaging techniques besides radiographs?
- Computed Tomography (CT)
- Magnetic Resonance Imaging (MRI)
- Ultrasound (US) Imaging
What is a CT?
Images generated by computerized and targeted x-rays passing through slices of tissue (.1 to 10 mm thick)
What are the major advantages of a CT?
- Less overlap of structures due to slicing
- Able to locate subtle bone changes
What are the major disadvantages of a CT?
- Greater radiation exposure but getting faster and safer
- Limited with soft tissue abnormalities
What can help add more detail to a CT?
Contrast agents
What is the standard modality for head and abdominal trauma in the ER due to shorter scanning times and quicker availability?
CTs
Are CTs or MRIs quicker?
CTs… they are also quicker than US
CTs start with what kind of image?
A Scout image
Scout images help you to locate what?
Locate specific slide position and image
A CT produces what plane slice images? (Sagittal, transverse, frontal)
Transverse
During a CT that patient is placed in supine so the image that is produced has the _____ surface at the top and the _____ surface at the bottom of each image slice.
Anterior at the top, posterior at the bottom
When looking at a CT you are looking upward at the anatomical structures from below so your _____ is the patients _____.
Your right is the patients left and vice versa
If you have a sagittal plane sliced CT image how would you view it?
Sagittal plane slices are viewed from left to right
T/F: Tissue density on a CT appears like the tissue density shades on an x-ray.
True
What is an MRI?
Strong magnetic field with radio-frequency waves
What similarities does an MRI have with a CT?
- Generates thin slices
- May also be used with contrast agents for even more detail
What are the major advantages from an MRI?
- Less overlap like a CT due to slicing
- Excellent in finding soft tissue abnormalities, cancellous bone/ bone marrow conditions (neoplasms and staging metastasis, osteochondral lesions, stress fractures)
- No radiation like with a CT (high) and X-ray (low)
- High resolution
What are the major disadvantages from an MRI?
- Contraindications with magnetic implants except for stable joint implants
- Precaution with claustrophobia
How do you view an MRI?
- The same way you would a CT
- Orient yourself to the scout image to find the slice you need
- View as with the CT
When diagnosing someone using an MRI it is often based off of differences seen in what?
T1 and T2 images
How can you tell the difference between a T1 and T2 image?
- Look for known areas of normal fluid first (ex: bladder, synovial joints, cerebrospinal fluid)
- If fluid is bright, it is likely a T2 image
- If fluid is dark, it is likely a T1 image
What will a T1 weighted image look like and what is it best used for? (bone, fat, etc.)
- Bright signals from fat and bone marrow
- Dark signals from cortical bone and fluid
- Best for demonstrating anatomical definition of structure
What will a T2 weighted image look like and what is it best used for? (bone, fat, etc.)
- Bright signal occurs from fluid and water
- Best for demonstrating swelling and neoplasms particularly in cancellous bone
Nerve and muscle have an intermediate signal and are often _____ with both T1 and T2 weighted images. (color)
Gray
Slide 48 and 49 have tables for T1 vs T2 images and coloring that will come with it and conditions
Look at the tables! These might be important!
What is an ultrasound or sonography?
Ultrasound waves are absorbed, reflected, and diffused differently from varying tissues to construct an image
What are the major advantages for an ultrasound or sonography?
- Offers real time information for superficial soft tissue
- Higher resolution for superficial tendon, ligament, and muscle then MRI
What are the major disadvantages for an ultrasound or sonography?
- Inability to scan deeper joint structures
- Image quality highly dependent on operator
If there is a brighter signal on a sonograph what does this mean?
Indicates swelling, tendinosis (fibrosis/ degeneration), aka hyperechoic appearance
If there is an irregular border or lack of structure on a sonograph what does this mean?
Indicates a tear(s)
If there is a wider structure on a sonograph what does this mean?
Indicates swelling and thickening
Slide 55 has a chart on abnormal and normal sonograms, look at this!
Slide 56 has a chart on US vs CT vs MRI… may be helpful
If there is no trauma, will the results of any imaging influence interventions or psychosocial factors?
Most likely no
What is imaging benefitted by?
A thorough history and exam
What are the clinical decision rules for imaging?
- Following trauma based on supportive clinical findings
- Diagnostic and prognostic decisions
- Evidenced based with research
What is the appropriateness criteria for imaging?
- Foremost decision- making guideline
- Guides choice of best imaging tool
- Developed by expert radiologists
- May use with or without trauma
What are factors for decision making for MSK conditions in regards to imaging?
- Age: individual risk factors including PMH
- Trauma presence/ absence
- Mechanism of injury
- Prior surgery/ injury/ imaging results
- Clinical findings, particularly pain provocation and function (ex: weight bearing ability)
Imaging without clinical findings is considered to be …
Normal/ asymptomatic
Imaging is (+) when it has …
matching clinical findings
Imaging can be negative with clinical findings of a condition, what is an example?
- Suspicious condition (ex: acts like a fracture but x-ray (-) so consider a more advanced and specific image, like a CT)
- No structural changes and more of a biomechanical or overuse etiology
Imaging can be positive without matching clinical findings, what is an example?
- Unrelated contributions to symptoms
- Potential negative effect on psychosocial status (fear of activity, failure to work, limit rehab potential)
Is imaging best at ruling out or ruling in?
Ruling out
