Medical Imaging Flashcards
Diagram: Identify the image below
CT image of left actabular fracture
Q: Sensitivity - A negative test means…
You definitely don’t have the condition
Term: Ability of the x-ray beam to pass through substance to reach the film plate
Permeability
Diagram: Radiograph coloring review
Q: What are the ABCs of Radiology?
Alignment, Bone Density, Cartilage, Soft tissue
Term: Atomic nuclei allign in an electromagnetic field
Resonance
Q: How are lateral view named?
For the side closer to the film plate
Content: 3 parts of soft tissue
- Gross size of musculature
- Outline of joint capsules
- Periosteum
T/F: A radiograph is simply a representation of the radiographic densities of anatomical structures
True
Diagram: Identify the problem
Metastic bone lesion (from primary lung cancer)
Q: What is the error rate in radiological interpretation (by radiologists and radiology residents)?
May be as high as 20-40%
Q: High object radiodensity results in _____________ radiography density on the film, thus the object appears ________.
Decreases, whiter
Term: Maximized by positioning patient so structure of interest is closest to film plate
Detail
Q: How does an MRI generate an electromagnetic field?
Uses pulses of radiofrequnecy and a strong external magnet
Term: How long resonating protons remain in phase following a RF pulse
Transverse magnetization (T2)
Defn: Errors of interpretation
The injury is there but the radiologist misses it. Ex. Fracture is there but is not seen
Diagram: Identify the problem
Osteoarthritis of the left hip, with joint collapse
Q: What gives an x-ray image with the most detail and least distortion?
Have the part of interest as close to the film or plate as possible
Q: What produces a radio frequency signal that can be captured and processed into an MRI image?
The release of resonant energy
Term: Clarity of the image
Geometric qualities
Defn: Contrast enhancement
Injection or ingestion of radiocontrast medium prior to radiographic study
T/F: diagnostic imaging and PT guides and informs the PT’s treatment plan.
True
Content: 3 disadvatnages of MRI
- Relatively low specificity
- Expensive
- Contraindicated if pt. has ferrous metal implant or exposure
Q: What are the 4 advantages of conventional radiographs (x-rays)?
- Time and cost efficient
- Non-invasive
- Low risk
- Good for screening
Term: Objects or structures further from the film appear larger than closer points
Magnification
Q: What is the first order diagnostic modality?
Conventional radiographs or x-rays
Q: What color is the exposed film in radiographic images?
Dark
T/F: With interpretation, insignificant findings may prove significant, while significant findings may prove insignificant.
True
Content: The 4 parts of alignment
- Gross bone size
- Number of bones
- Shape and contour of cortical outline
- Joint position and alignment
T/F: In x-rays, one view is no view.
True, in terms of interpretation. X-rays are 2D images, need more than one image to reconstruct into 3D
T/F: Diagnostics are the tools and are the answer.
False: they are a tool, NOT the answer.
Q: What can a PT offer when interpretation is difficult for even the specialist? (3)
- Managing care 2. Directing imaging 3. Relating imaging studies to clinical evaluation
T/F: Diagnostic findings, including imaging, must be used in the context of clinical presentation.
True
Defn: True positive
Test detects something that is really there
Defn: False positive
Test detects something that is not really there
Defn: Specificity
A test’s ability to identify a true negative
Q: What is the least radiodense stubstance in the body?
Air
Diagram: Identify the problem
Biconcave “fish” vertebrae, indicative of osteopenia
Diagram: CT Basics
Diagram: Identify the problem
Osteonecrosis of femoral head, femoral head begins to flatten
Defn: Errors of observation
The image doesn’t look like what you think it is Ex. Fracture doesn’t show up
Term: Reduced strength or density of the x-ray beam as it passes through a medium
Attenuation
Diagram: Identify the problem
Fat pad or “sail” sign: note faint density change at arrows as edema pushes fat pad out of fossa
Defn: False negative
Test detects nothing, but there is something there
Q: Given that HIV blood tests are very sensitive, what can you assume about the presence of the virus from a negative test?
That the test will rarely come up negative is the virus is present - SNOUT
T/F: Ortopedic hardware is ferromagnetic, however surgical clips and pacemakers are safe during an MRI.
False, flip it
Term: How long it takes protons to relax back to resting state following a RF pulse
Longitudinal magnetization (T1)
T/F: The radiodensity of an object is directly related to the radiodensity (amount of blackening) on the radiograph.
False: inversely
T/F: Diagnostic imaging and PT improves the PT/physician communication.
True
Diagram: In the image below label each line
Red = anterior vertebral line
Blue = posterior vertebral line
Green = spino-laminar line
Orange = posterior spinous line
Term: Refers to a test’s ability to identify a true negative
Specificity
Q: With ________ MRI, tissue enhancement is ______________ to blood flow to the tissue.
Contrast, proportional
Q: What acronym is helpful for specificity?
SPIN Specificity, Positive, Ruled In
Diagram: Identify the problem
Left intertrochanteric and subtrochanteric hip fractures
Term: visibility of the image
Photographic qualities
Term: also known as sharpness or resolution
Detail
Q: What are the 2 advantages of CT?
- Sensitive and specific for fracture
- Useful for rapid assessment of brain or neurologic injury
Q: By what percent was diagnostic imaging reduced when military PT’s were given the ability to order images.
50%
Q: List the substance that represents the color on radiograph (shown below) from darkest to lightest.
- Air
- Fat
- Water
- Bone
- Contrast Media
- Heavy Metals
Table: Fill in the table below
Term: amount of blackening on the radiograph dependent on distance, time, and current
Density
Term: Image appears shorter and wider than the actual object or structure
Foreshortening
Q: What is the main disadvantage of conventional radiographs?
They may be normal when a pathology actually exists
Q: Given that home pregnancy tests are very specific, what can you assume about the presence of a pregnancy from a positive test?
That a positive test is almost always due to pregnancy - SPIN
Q: What are the 3 disadvantages of CT?
- Radiation exposure
- Discriminates density, but limited in precise histologic differences
- Small volume of tissue image as a uniform shade of gray
T/F: Diagnostic imaging and PT adds nothing to the comprehensive PT eval.
False: enhances
T/F: PT’s should be independently interpreting imaging results.
False
Term: Refers to a test’s ability to identify a true positive.
Sensitivity
Q: During an MRI, nuclei realign to their _________ state when the field is _________, release _________ energy.
Resting, removed, resonant
Table: Fill in the table below
Term: Usually occurs due to distance between beam source, patient, and image receptor, and from alignment and positioning issues
Distortion
Content: 4 parts of cartilage
- Joint space width
- Subchondral bone
- Joint margins (smoothness)
- Epiphyses and growth plates
Diagram: Identify the problem
“Teardrop” fracture of 2nd cervical vertebrae
Term: differences between adjacent tissue densities
Contrast
Term: easily penetrated by x-rays - i.e. low attenuation
Radiolucent substance
Diagram: Identify the type of MRI image.
T2 image of a herniated lumbar disk
Defn: True negative
Test detects nothing and nothing is there
T/F: MRI images are based on two different processes of proton realignment.
True
Term: X-ray absorption capacity, based on substances composition, density, and thickness
Radiodenisty
Q: Specificity - A positive test means…
You definitely have a condition
Q: What are the 3 common radiograph names?
anterioposterior (AP), posterioanterior (PA), Lateral/oblique
Diagram: Identify the contrast enhancement
Barium swallow
Diagram: X-ray Basics
Diagram: Identify the problem
Compression fracture of 4th lumbar vertebrae
Q: What is one thing to be careful of when viewing radiographs?
The identification letters may appear backward or upside down
Content: 4 advantages of MRI
- Good sensitivity
- Images soft tissue well
- No radiation
- Little distortion as images are obtained in one plane
Term: Not easily penetrated by x-rays - i.e. high attenuation
Radioopaque substance
Q: How are radiographs named?
For the beam directions relative to the patient/patient position
Content: Computed tomography basics (4)
- Uses x-ray attenuation to produce cross-sectional images
- X-ray tube and film move about a fulcrum
- Provides detailed anatomical imaging of bone
- Travserve images are read from the bottom looking up
Q: In what ways can MRI contrast be delivered into the pt.’s system?
IV or intra-joint injection
Q: What contrast media is typically used?
Barium sulfate (in swallow studies)
Diagram: Identify the image below
3D image of tibial plateau and proximal fibular fractures
Defn: Sensitivity
A test’s ability to identify a true positive
Content: 4 parts of bone density
- Cortical margins dense, lower density in cavity
- Weight bearing should be higher density
- Osteoporosis is suggested by low contrast - “washed out”
- Sclerosis or arthritis will appear as a brighter white
Q: What acronym is helpful for sensitivity?
SNOUT Sensitivity, Negative, Ruled Out
Diagram: Identify the type of MRI image
T1 image of right hip chondrosarcoma
Diagram: Idenifty the type of MRI image
T2 image of tibial plateau and femoral condyle contusion
Content: Functional MRI (2)
- Based on increased BF that accompanies cerebral activity
- Uses magnetic properties of deoxyhemoglobin as an endogenous contrast agent
Content: DEXA (4)
- Gold standard for body composition
- Measure bone density
- Determines density based on difference between absorption of beams
- Radiation exposure approx. = to a flight from NYC to LA and back
Content: Nuclear Medicine (3)
- Uses radiopharmaceuticals for diagnosis, therapy, and reserach
- Radiopharmaceuticals are radioactive tracers that are absorbed according to the metabolic properties of the tissue
- Detection of the location and concentration of radioactive elements is used to produce an image
Content: Types of Nuclear Medicine (4)
- SPECT
- PET
- SPECT or PET in combo with CT
- Radionuclide scintigraphy or bone scan
Content: Radionulcide scintigraphy (3)
- Labeled methylene is injected, scanning occurs 2-3 hours following injection
- High uptake = increased bone activity or mineral turnover
- Modality of choice for detecting stress fractures and metastatic bone disease
Content: 3 advatanges of radionuclide scintigraphy
- Highly sensitive for early bone and joint disease
- Fast
- Reasonable cost
Content: 2 disadvantages of radionuclide scintigraphy
- Poor specificity
- Easily influenced by osteoblastic activity or BF of any etiology
Diagram: Idenifty the type of image
Radionuclide scintigraphy - metastatic prostate cancer
Content: Ultrasonography (4)
- Images produced by sound waves
- Tissues have unique acoustic qualities
- Useful for OBGYN and musculoskeletal tissue
- Can be used with activity
T/F: Ultrasound is operator independent, and does not require practice to have good technique.
False
T/F: Ultrasound is included in the PT practice act, but should only be used to confirm diagnosis.
True
Q: ____________ ____________ are generally the first order modality.
Conventional , radiographs
Q: ______ is used to visualize complex anatomy
CT
Q: ________ is used to assess soft tissue.
MRI
Content: 3 parts of a trauma survey
- Diagnose and evaluate fracture or disloaction
- Match MOI to clinical presentation
- Assess treatment and monitory healing
Q: What types of images are typically taken for a trauma evaluation? (3)
- Lateral chest
- AP chest
- AP pelvis
Diagram: Identify the following clinical decision rule;
Sensitivity ______, Specificity ______
Pittsburg Decision Rule for Knee Trauma
99%, 60%
Diagram: Identify the following clinical decision rule;
Sensitivity ______, Specificity ______
Ottowa Knee Rule
97%, 27%
Diagram: Identify the following clinical decision rule;
Sensitivity ______, Specificity ______
Ottowa Ankle and Foot Rules
100%, 40%
Diagram: Identify the following clinical decision rule;
Imaging Guidelines for Actue LBP
