Medical Imagining Flashcards
1
Q
When is imaging not needed?
A
- when the image will not change the treatment
- when there is no treatment available
- when the patient will not consent to the treatment
2
Q
When is imaging needed?
A
there are different scales and rules used to determine a patient’s need for imaging
- Canadian C-spine rule
- Ottawa ankle index
- Ottawa knee index
- nation emergency X-ray utilization study low risk rule
3
Q
What are some factors for decision making according to the American college of radiology appropriateness criteria?
A
- age
- individual risk facttors
- trauma presence/absence: physical appearance
- mechanism of injury
- neurological status/deficits
- prior surgery
- pain provocation/reduction of physical functional tests
- other imaging results
- weight bearing ability
- tenderness to palpation
4
Q
Radiography
A
X-rays
- produce analog or digital image
- ionizing radiation (what can cause cancer)
- what to keep it to ALARA (As Low As Reasonably Available)
5
Q
What are some factors to consider when keeping the radiation of an X-ray ALARA
A
- intensity of radiation
- number and types of images (most cases need 2)
- distance from beam
- patient shielding
6
Q
X-Rays: How can they are affect the body and how are the images produced?
A
- can ionize matter/change cellular function
- can disrupt cellular processes
- can be used to produce an image through attenuation
7
Q
Attenuation
A
- Occurs as X-rays passes through the body
- reduction in number of x-ray photons in beam
- occurs as photons interact with matter
- the photons will scatter which is dependent on density of tissue
- photoelectric absorption
8
Q
Attenuation radio density of tissues: rank from least dense to most dense
A
- air
- fat
- water
- bone
- metal
9
Q
Other shades of imaging: contrast images
- positive vs negative contrast
A
- Contrast images: something is ingrested or injected to show certain tissue
- Eg: barium
- makes soft tissue more visible on radiograph
- positive contrast media,show up/lights up
- negative contrast such as air shows up black
10
Q
Other shades: metal
A
- surgical metal
- accidents, trauma (GSW)
- the thickness affects the radio-density such as edges of bones are not as dense as the middle
11
Q
What are the different views that can be used for radiography
A
- anterior-posterior (enters anterior exits posterior)
- posterior-anterior (enters posterior/exits anterior)
- lateral (left or right)
- 2 oblique views
12
Q
describe the lateral views
A
- left lateral: enters right and exits left
- right lateral: enters left and exits right
13
Q
what are some considerations when looking at a radiography
A
- distortion
- exposure
- contrast
- motion
14
Q
Osteoporosis in an image
A
- edges have high density
- grey on the inside
- decrease in bone density means they are more likely to sustain a fracture
15
Q
Ankylosing Spondylitis
A
- fusing of the spine with inflammation
- an inflammatory process that caused the spine to fuse
16
Q
CT/CAT scan
A
- computed axial tomography
- cross-sections slices
17
Q
CT uses
A
- subtle and or complex fractures
- degenerative changes in bone and joints
- serious trauma (can image bone and soft tissue)
- spinal stenosis (impingement of spinal nerves)
- intervertebral disk
- loose body in joints
- bony alignments in any place
18
Q
CT imaging
- acquired?
- density
- slices thickness
A
- images can be acquired in coronal, sagittal or axial plane
- image density can be selected to emphasize soft tissue or bone
- thickness of slices can allow for more detailed views of structures
19
Q
CT vs MRI
A
- CT is faster
- less incidence of claustrophobia
- less expensive than MRI
- MRI is better at looking at differences in soft tissue
- MRI does not use radiation
20
Q
MRI: How it works?
A
- uses protons in hydrogen atoms in the patients body and an electromagnet to produce an image
- hydrogen found in body in
~free water in body fluids (CSF)
~ water bound to large molecules like proteins
~hydrogen atoms in fat
21
Q
What are the types of MRI imaging
A
- T1
- T2
- others: FLAIR, SPIN, STIR
22
Q
T1 MRI
A
- shortest acquisition time
- can see fat, acute hemorrhage will appear brightest (highest signal intensity)
23
Q
T2 MRI
A
- longer acquisition time
- can see free water with inflammation, tumors, synovial fluid, CSF will appear brightest
24
Q
Other types of MRI: FLAIR, SPIN, STIR
A
- used for specific diagonostic purpose eg CNS and brain injury
25
Clinical uses for MRI
- excellent for soft tissue assessment
- musculoskeletal and sports injury
- can assess integrity of tendons, ligaments, menisci
- bone marrow changes, eg. neoplasm, stress fracture, avascular necrosis
- disc herniation, nerve root impingement
26
Limitations to MRI
- time: takes a long time 40 min. to an hour
- expensive
- availability is limited
- contraindications: any ferrous metal in body risks injury or death
- precautions: pacemaker, claustrophobia
27
Iodine-containing contrast medium
- used for X-ray and CT to better view soft tissues
- Oral, IV, injection or other
28
- cautions: for Iodine-containing contrast medium
- patients with reduced kidney function (contrast-induced nephropathy/kidney disease)
- patients with iodine allergy (mild to severe)
- elimination is through the kidney and can damage it
29
Gadolinium-based contrast
- 1 in 3 MRI use contrast
- given through IV
30
cautions for Gadolinium-based contrast
- patients with reduced kidney function (nephrogenic systems fibrosis)
- less risk of allergic reaction than iodine
- elimination in about 24 hours
31
Other medications that can be used with
1. CT or MRI
2. CT with contrast
1. medication to reduce anxiety or claustrophobia
2. steroid if previous allergic reaction
32
Ultrasound (MSKUS)
- can be used instead of MRI to assess soft tissue
- uses sound waves
- other healthcare workers can do it
- can vary in time
33
Ultrasound advantages
- portability, ease of use, lower cost
- no known contraindications
- movement is not a concern
- quick comparison to opposite side
- high resolution
- can follow a structure from beginning to end
- shows internal architecture of muscle tendon, and ligaments better than an MRI
34
Doppler US
- evaluates blood flow
- vascular for blockage
- DVT diagnosis
- cardiovascular
- joint capsule
35
Abdominal US
- used to assesinternal organs
- complete abdominal US also includes
1. kidney
2. spleen
3. bladder
4. abdominal blood vessels
36
1. Right upper quadrant
2. right lower quadrant
3. left upper quadrant
4. left lower quadrant
1. liver, pancreas, gallbladder, duodenum, right kidney, hepatic flexure
2. cecum, appendix, right ureter
3. stomach, spleen, left lobe of liver, left kidney, spleenic flexture
4. descending colon, sigmoid colon
37
Abdominal ultrasound common conditions
- bladder stones
- gallstones
- cholecystitis: gallbladder inflammation
- enlarge spleen (splenomegaly)
- pancreatitis
- cancer (stomach or pancreatic)
- fatty liver disease
- abdominal aortic aneurysm
38
Arthrography
can identify abnormalities of synovium, ligaments, articular cartilage and joint capsule
39
Myelography
- generally used to look at things with the spine
- type of X-ray
40
Tomogram
- used before CT
- X-ray tool that can be moved
41
Nuclear Medicine
- uses a radioactive substance called a tracer
- the tracer is administered to the patient with injection, inhalation, or ingestion
- the tracer allows for evaluation of the function of a specific organ
- image produced using a gamma camera
- can create static or moving images
(look at things like how blood is flowing through an organ or the GI tract
42
Nuclear medicine types
- bone scan/bone scintigraphy: looks for areas of hyper function, increased mineral turnover (new bone being laid down)
- positron emission scan (PET scan) : mostly in neuro
- single positron emission CT (SPECT): used for detecting small abnormalities in bone, heart, brain, or liver (organs)
43
What is interventional radiology
- epidural steriod injections
- spinal nerve blocks
- radiofrequency ablation (heart surgery to get rid of excess tissue)
- percutaneous needle biopsy (through the skin)
- vertebroplasty, kypoplasty (plasty means repair - these are postural repairs)
