Intro to Radiology Flashcards
The following definition describes what modality:
Shadow-like 2D images of radiographic densities obtained from passing x-rays through the body
Radiograph
X-rays are ___ energy, the same as radio waves, microwaves, or visible light - except their very low wavelength and high energy allow them to penetrate and interact with the body, and potentially cause ionization
electromagnetic
A proper term for something that looks bright on an x-ray image is ____, while something that looks dark is ____
radiopaque; radiolucent
List the 5 radiographic densities within the body and put them in order from least to greatest
Air, fat, water, bone, and metal
True or false?
Density is affected by the thickness of what is being imaged
true
note: this concept is important because we cannot distinguish different anatomy shown on a radiograph unless the different structures have different radiographic densities
What are the advantages of radiographs?
fast and relatively inexpensive ($200-500, also available nearly everywhere and demonstrate bone and metal very well
What are the disadvantages of radiographs?
Use ionizing radiation, give limited information for soft tissues, shadows from other anatomy can become superimposed, magnification issues, blurring due to patient motion
The following definition describes what modality:
A form of x-ray image, obtained by passing x-rays through the patient onto a fluoroscope, usually captured as a combination of video and still images
fluoroscopy
What are the advantages of fluoroscopy?
can image anatomy in real-time, by using different contrasting agents, these can see inside body cavities, such as bowel, bladder, etc., relatively inexpensive
What are the disadvantages of fluoroscopy?
sometimes can accumulate significant radiation exposure for patient or personnel. Contrast agents can be unpleasant or can cause allergy, nausea, or renal damage
The following definition describes what modality:
All the minimally invasive procedures performed by radiologists using various modalities of imaging for guidance
intervential procedures
What are the advantages of intervential procedures?
minimally invasive and less expensive than open surgeries, can make diagnosis from procedure, as well as treat condition
What are the disadvantages of intervential procedures?
complications, blood product/body fluid exposure to personnel, radiation exposure
The following definition describes what modality:
a radioactive substance is introduced into the body- designed to travel to the organ being studied. Gamma rays are emitted by the radiopharmaceutical as it enters and exits the organ of interest, which are imaged using a gamma camera
nuclear medicine
In regards to nuclear medicine, the term for what shows on the image is ____ ___ or “hot”, relative to the other areas that may be ___ ___ or photopenic
increased uptake; decreased uptake
An advantage of this modality is excellent at showing organ function
nuclear medicine
What are the disadvantages of nuclear medicine?
do not image organ anatomy in great detail. Expensive, ionizing radiation
The following definition describes what modality:
covered in ultrasound lab
ultrasound
Something bright on an ultrasound image is termed ____, while something dark is ____
hyperechoic; hypoechoic
The following is an advantage of what modality:
relatively inexpensive, zero ionizing radiation. Real-time imaging. can directly image in any plane. although IV contrast agents exist, they are seldom necessary to image vasculature
ultrasound
What are the disadvantages of ultrasound?
hard to image deep structures, so it is often difficult to image obese patients or immobile patients who may be difficult to position ideally. ultrasound does not travel well through bone or air so certain anatomy is not seen well. anatomy is difficult to interpret without proper training
Define the modality of computed tomography (CT)
a specialized modification of x-rays - where the x-ray tube and x-ray detectors are resolved/spiraled around the patient - as the patient is moved through the machine. x-rays striking the detectors are converted to images by computer. while passing through the body - some of the x-rays are attenuated (absorbed or lost)
When looking at a CT, the proper term for something that looks bright is high ____, while something that is dark is low ____
attenuated; attenuated
What are the advantages of CT?
excellent cross sectional anatomy, with tremendous radiographic density resolution. rapid. widely available. excellent guidance for interventional procedures. non-invasive vascular imaging
What are the disadvantages of CT?
expensive. cumbersome for the very ill. ionizing radiation. metal causes artifact. Iodine-based IV contrast complications
The following definition describes what modality:
by subjecting the body’s protons to very strong magnetic fields, the direction they are pointing and their rate of spinning can then be known. once the rate of spinning is known - radio waves of the same frequency can be applied to them. since their frequencies are matched - the protons absorb energy from those radio waves
magnetic resonance imaging (MRI)
Advantages of MRI
excellent cross sectional anatomy, especially soft tissues. zero ionizing radiation. non-invasive vascular imaging. when needed, its IV contrast has fewer complications than Iodine-based contrast. provides good guidance for interventional procedures
Disadvantages of MRI
expensive. contraindicated for some. artifact may be unavoidable because a patient cannot hold still, or because of certain kinds of metal within the patient. the very obese often do not fit. MRI is not often widely available
