Introduction to radiology Flashcards
When choosing imaging modalities, what should you look at?
-indications
-patient status
-reliability
-risks and benefits
-need for multiple studies
What determines what modality to start with?
patient status
What type of practice are these associated with?
-imaging usually ordered during patient visit
-patient goes to imaging center/scheduled for diagnostic test
family practice
What type of practice are these associated with?
-most places have x-rays
-not common to have other imaging equipment
urgent care
What type of practice are these associated with?
-has x-rays, CT scan, ultrasounds (bedside; duplex)
-do not routinely order MRI scan emergently
Emergency departments
What type of practice are these associated with?
-may have own equipment due to heavy use
specialty settings
What are the different imaging ordering components?
-patient name and demographics
-diagnosis
-reason (not just the patient’s symptoms; provide some history)
-may need to provide laboratory findings (pregnancy status, kidney function (contrast)
-location
What are the different types of forms used for imaging orders?
EMR
Forms
What are the components of imaging ordering that fall under location?
-laterality (right, left, bilateral)
-anatomic area (right shoulder vs. right humerus; abdomen vs. abdomen and pelvis)
What must you know for radiology?
anatomy and anatomic landmarks
What assists with determining the location of a lesion?
contrast agents
What are contrast agents used to visualize?
-spinal cord
-blood vessels
-GI tract
-ureters
-bladder
How are contrast agents delivered?
-orally
-intravenously
-rectally (not as common)
What can contrast agents reduce?
kidney function
What must you assess/know before ordering imaging with contrast?
kidney function
What should you do when you order imaging with contrast?
-order BUN/Creatine when ordering CT scan
-consider pregnancy test
Contrast reactions are deemed what when using contrast agents?
low risk
What does the approach to imaging interpretation consist of?
-Pt identification (name, age, gender)
-date of study (compare to old studies when available)
-know what imaging modality you are evaluating
**plain film vs. CT with or w/o contrast
**orientation (AP, lateral, oblique)
**laterality (right, left bilateral(
**with or without contrast (CT w contrast in coronal, frontal, or axial view)
What do you took at when considering technical quality of imaging interpretation?
-appropriate position of the body
-quality
-contrast
-over or under exposure
What should your systematic approach to imaging modality consist of?
-need to understand normal anatomy (anatomic landmarks)
-know common anatomic variants
-avoid naming the abnormality as a specific disease
**realize what is abnormal, then think about disease pathologies that can cause the abnormality
What should you note about imaging interpretation and when you will provide the interpretation?
it is setting dependent
-primary care
-ED/UC/Specialty setting
In a primary care office, how do providers receive/interpret images?
-provider receives reports from radiologist
-could also review the images if they have access to EMR
In an ED/UC/specialty center, how do providers receive/interpret images?
-provider may be required to read own films with opportunity to request read by radiologist
-providers in many specialty settings will read their own images and compare to radiologist impression
What is the most ordered imaging modality?
plain films
What is usually the initial imaging technique?
plain films
What are some advantages to using plain films?
-cost effective compared to other studies
-easy access
-quick
-good for finding basic emergent findings
What are some disadvantages to using plain films?
-difficult to make definitive diagnosis (soft tissue pathology)
-need additional studies
Who were plain films started by?
Wilhelm Rontegen in 1895
What occurs in a plain film?
xray beam passes through the body
What is the term used to describe how the beam is weakened and is tissue dependent so densities will appear as different shades?
attenuation
In plain films, what color is air/gas?
black or dark gray
In plain films, what color is fat?
gray; lighter than air; darker than muscle
In plain films, what color is water?
various shades of gray
In plain films, what color is mineral?
white
In plain films, what color is metal and contrast agents?
bright white
What type of attenuation does air have?
low attenuation
What type of attenuation does bone/metal have?
high attenuation
What are the different positioning for plain films?
AP
PA
lateral
oblique
supine
upright or standing
In plain films, what does positioning affect?
magnification, organ positioning, and blood flow
What type of studies are two-dimensional views of 3D structures?
plain films
What must plain films always have?
2 views at right angles of each other (orthogonal images)
What are the indications of plain films?
-initial imaging technique
*bony abnormalities
*structural changes (cardiopulmonary changes
*screening for cancer and/or other pathologies (pneumonia)
*foreign bodies
What are the contraindications of plain films?
no defined contraindications
What is fluoroscopy associated with?
plain films
What is a continuous x-ray imaging that does spot filming or video recording?
fluoroscopy
What procedures is a fluoroscopy used in?
-assessing movement of a body part
-insertion of an instrument
-monitoring movement of a contrast agent
What started in the early 1970s and is described as a rotating fan of xray beams through the patient?
CT scan
In what type of imaging are the transmission points calculated by a computer and produces an image and also has the ability to make “windows” and 3D reconstructions?
CT scan
What is the ability to manipulate images to be able to see things more/better?
“windowing”
What measures the density of structures and provides the ability to delineate structures within the defined window?
Windowing - hounsfield units
What is the unit used to describe density of structures?
hounsfield units
With high HU (hounsfield units), what would you be getting a better look at?
bones - bone windowing
What with low HU give you a better look at?
organs such as the lungs
What is the attenuation of CT scans?
same as xrays
What color is air in a ct scan?
black
What color is fat in a ct scan?
dark gray
What color is soft tissue in a ct scan?
light gray
What color is bone/calcium in a ct scan?
white
What color is contrast in a ct scan?
white
How should you interpret CT/MRI scans?
as if you are looking at the patient from the foot of the bed
What are the different type of CT scanners?
-traditional ct
-helical ct
-multidetector ct
What type of CT scanner is this describing:
-patient is moved into position, gantry stops, image is taken
-repeated for all sequences
-up to 5-10 minutes
traditional
What type of CT scanner is this describing:
-moves continuously through the gantry at constant speed, decreasing artifact from patient movement
-under 1 minute
helical
What type of CT scanner is this describing:
-uses helical technology, but adds multiple detector rows
-8 times faster, improves resolution, and provides detailed images
multidetector
What are the advantages of a CT scan?
-more effective medical management
-evaluate structures not visualized on plain films (internal structures; diarthrodial joints)
-visualize multiple structures at once
-quick scan (10 minutes)
-noninvasive
What are the disadvantages to CT scans?
-increased radiation exposure
-cost, depending on the scan
What ways can contrast be taken for CT scans?
IV
oral
rectal
Why would contrast be good to use?
can be used for differentiating solid vs cystic masses and for fluid accumulation (abscesses)
What are some examples of CT scans for musculoskeletal use?
-joints that aren’t seen well with x-rays (SI joint, vertebral bodies)
-intra-articular fractures
-bony abnormalities
-soft tissue abnormalities
What uses magnetic field to align hydrogen atoms, and then a second magnet field is applied, and radiofrequency pulses pass through the nuclei to create the image?
captured images are then analyzed by a computer and images are generated
MRI
Instead of attenuation, MRIs use what?
intensity
What color is high signal intensity with MRIs?
white
What color is intermediate signal intensity with MRIs?
gray
What color is low signal intensity with MRIs?
black
When comparing two structures in MRIs, you can use what terms?
-hyperintense
-isointense
-hypointense
What are pulse sequences in MRI terminology?
-refers to how the protons are manipulated
-tissue properties determine the pulse sequence
What describes how protons interact with surrounding tissue in MRI terminology?
T1
What describes how protons interact with each other in MRI terminology?
T2
What is the density of protons within a region called in MRI terminology?
proton density
What is Fluid attenuated inversion recovery (FLAIR)?
T2 sequence that suppresses the brightness of water
What do FLAIR MRIs help differentiate?
abnormalities that obscured by water (CSF, Edema)
What is short T1 inversion recovery described as?
-suppresses the brightness of fat
What do STIR MRIs get better visualization of?
tumors and inflammation
When can’t you evaluate STIR images?
when gadolinium contrast is used
What type of MRI image is based on the motion of water molecules?
diffusion weighted imaging (DWI)
In diffusion water imaging, more water intracellularly is associated with what?
injury/disease
In diffusion water imaging, decreased movement is associated with what?
tumor
What type of imaging differentiates soft tissue and will display different signal intensities because of tissue pathology?
MRI
In T1, fat is ____ and water is _____
bright; dark
In T2, fat is ____ and water is ____
dark; bright
What is difficult to see on an MRI?
bone
What are you seeing instead of calcium in MRIs?
fat in the bone barrow
What are the contraindications associated with MRIs?
-implants/metal devices
-retained metal objects/foreign bodies
-severe claustrophobia
-pregnant or breastfeeding (contrast is a category C)
What are the advantages of MRIs?
-no radiation
-better tissue contrast than CT scan
What are the disadvantages of MRIs?
-artifact due to patient moving
-longer scan times
-expensive
-safety concerns: magnet strength
-loud, knocking noises during the scan
What are MRIs with contrast used to evaluate?
-tumors
-inflammation
-blood supply
-organ/joint features
What does gadolinium do for MRIs?
increase intensity
What is gadolinium best used for viewing?
T1 weighted images
**does not contain iodine
What imaging technique uses high frequency, inaudible, sound waves?
ultrasound
In ultrasounds, what are images produced by?
the echo phenomenon
What is the Echo phenomenon?
-waves travel through tissue and each has different acoustic properties
-return velocity are collected by piezoelectric crystals in transducer
-images displayed in gray scale
An anechoic echogenicity describes what?
no echoes (black)
A hyperechoic echogenicity describes what?
strong echoes (white)
What is the attenuation of fluid in untrasounds?
black
What is the attenuation of bone in ultrasounds?
white
What is the attenuation of tissue in ultrasounds?
various shades of gray (depends on density)
Fluid is ______
Soft tissues are _______
Bone/air are ______
anechoic
hypoechoic
hyperechoic
What does the doppler effect on ultrasounds analyze?
the returning echo from the motion of blood flow
In doppler ultrasounds, what does red/orange colors depict?
blood flow toward the transducer
In doppler ultrasounds, what does a blue color depict?
blood flow away from the transducer
What are the advantages of ultrasounds?
-no radiation
-readily available/portability
-less cost than other imaging modalities
-used at bedside (real time images)
-doppler evaluation (blood flow)
-not affected by metallic objects
What are the disadvantages of ultrasounds?
-operator error
-ability to evaluate tissue with high impedance (organs obscured by overlying bowel gas)
-possible injury to thermal heating
-could be limited by body habitus
What other diagnostic imaging is not used as much but is used to evaluate for disc herniation and spinal cord compression from a tumor or trauma?
myelogram
What other diagnostic imaging uses radionuclide imagine and shows increased uptake such as increased blood flow, increased osteoblastic activity and heightened metabolic activity?
nuclear medicine (bone/PET scan)
What is the field of medicine that utilizes medical imaging for minimally invasive procedures?
interventional radiology
What has interventional radiology replaced the need for?
open surgeries
What are the pros of interventional radiology?
-decreased recovery time
-decreased risk of infection and other complications
-decreased hospital stays
-improved morbidity and mortality
What types of procedures can be done in interventional radiology?
-angiography/angioplasty
-gastrostomy tubes
-stent placement
-needle biopsies
-IVC filters
-catheter insertions
-cancer treatments
