Radiology Exam 1: Key Terms & Definitions for Medicine

when were x-rays disocered?

november 8, 1895

who discovered xrays?

Wilhelm Conrad Roentgen

what are 4 advantages to conventional radiography?

quick to acquire, inexpensive to produce, obtained almost anywhere, most widely obtained imaging studies

what are 3 disadvantages to conventional radiography?

limited range of densities, reliance on ionizing radiation, radiation has the potential to produce cell mutations

name some common uses of conventional radiography

identifying fractures, surgery, studies, etc

what are the 5 basic densities seen on conventional radiography?

air, fat, fluid or soft tissue, calcium, metal

what is the appearance of air density?

absorbs the least x rays and appears "blackest" on conventional radiographs

what is the appearance of fat density?

gray, somewhat darker (backer) than soft tissue

what is the appearance of fluid or soft tissue density?

both fluid (blood) and soft tissue (muscle) have the same density on conventional radiographs

what is the appearance of calcium density?

the most dense, naturally occurring material (bones); absorbs most xrays

what is the appearance of metal density?

usually absorbs all xrays and appears the "whitest" (bullets, barium, etc)

what are CTs/CAT scans?

computed tomography

when were computed tomography first introduced?

1970s

CT scanner is connected to a computer t/f

true

how does a CT scanner produce images?

processed data through algorithms to produce images

CT image is composed of a matrix of thousands of tiny squares called ________

pixels

each computer-assigned a CT number from __________ to _________ called what?

-1000 to +1000 called Hounsfield units (HU)

CT number varys according to what?

the density of the tissue

CT number is what?

a measure of how much of the xray beam is absorbed

water has a HU of?

0

air and fat have HU numbers of negatives or positives?

negatives

soft tissue, bone, and metal have HU numbers of negatives or positives?

positives

what are Hounsfield units?

a range of pre-selected numbers to best demonstrate the tissues being studied

anything within the range of -100 to +300 is displayed over the available grey scale. this range of displayed densities is called the __________

window

denser substances = low or high CT numbers

high

demonstrate increased attenuation = blacker or whiter on CT images

whiter

conventional radiographs = metal/calcium appear blacker or whiter = increased density or more opaque

whiter

less dense substances-absorb fewer xrays = low or high numbers = decreased attenuation - display black

conventional radiographs = air/fat appear blacker or whiter = decreased density or increased lucency

blacker

what are the 3 standard imaging planes?

axial, coronal, sagittal

axial plane (or transverse)

divides the body into upper and lower segments

coronal plane

divides body into anterior and posterior sections

sagittal plane

divides body into left and right

what is the sagittal plane called if its located midline in the body?

midsagittal (or median) plane

CT scanning expands the grey scale versus 5 basic densities in conventional radiography t/f

true

Patients with implanted devices can safely be scanned with CT as opposed to MRI t/f

true

MRIs utilize ionizing radiation like conventional radiography, where CTs do not. t/f

false; CTs utilize ionizing radion, MRIs do not

CT scans are the cornerstone of what imaging?

cross sectional

CTs can display any body part in any plane including 3-dimensional rendering in color t/f

true

how do ultrasounds work?

use high frequency sound waves outside the range of human hearing to compare the relative densities of tissues in the body

Ultrasound probes use _______ energy

acoustical

An ultrasound probe or transducer both produces the

ultrasound signal and records it. t/f

true

how are images displayed in ultrasounds?

as static images or in video (cine) form

what are 4 advantages to ultrasounds?

relatively inexpensive, easily available/portable, widely used in medical imaging, the study of first choice because very safe imaging

modality

what are 4 disadvantages to ultrasounds?

cannot penetrate bones, gas-filled structures disrupt the signal, difficult to visualize deep structures in

obese patient, operator dependent

_______ utilizes the potential energy stored in the body's

hydrogen atoms, mostly those in water.

MRI

how do hydrogen atoms be made to act like a small magnet?

from nucleus containing a single proton

how do hydrogen atoms play a role in MRIs?

they are manipulated by scanner's extremely strong magnetic fields

and radiofrequency pulses and produce enough localizing and tissue-specific energy to generate 2 - or

- 3 dimensional images from that energy

some patients may receive an IV dose of _______ for MRIs

gadolinium

gadolunium

rare earth metal, used primarily for better detection of lesions (tumors,

abscesses, metastases) and for imaging blood vessels (MRI Angiography)

what are 3 advantages to MRIs?

no ionizing radiation, provides superior contrast between soft tissues, can differentiate better between fat, water, muscle,

and other soft tissues.

what are 3 disadvantages to MRIs?

not widely available, expensive, safety issues associated with the extremely strong

magnetic field

what is MRI widely used in?

neurologic imaging and soft tissues (muscles, tendons, ligaments)

_________ utilizes ionizing radiation in

performing real-time visualization of the body

fluoroscopy

what does fluoroscopy require?

specially fitted x-ray unit for controlled

motion of source, imaging sensor, and patient

how are instantaneous snapshots in fluoroscopy obtained?

by radiologist

how are overhead images in fluoroscopy obtained?

by radiologic technologist

how is fluoroscopy interventional radiology?

iodinated contrast

injected into select blood vessels

whats an advantage of fluoroscopy?

units can be made mobile and provide real-time visualization

whats a disadvantage to fluoroscopy?

uses ionizing radiation

what uses higher doses of radiation, fluoroscopy or conventional radiography?

fluoroscopy

what is fluoroscopy used extensively for?

following location and path

radioactive isotope (radioisotope)

unstable form

of an element that emits radiation from its nucleus as

it decays

Radioisotopes used in clinical nuclear medicine referred to as ________, _________ or __________

radionuclides, radiotracers, or

tracers

radioisotopes can be produced artificially or occur naturally but the vast majority of radioisotopes used in medicine are what?

produced artificially

whats the most common radioisotope used in nuc med?

Technetium-99m

Single Photon Emission Computed Tomography (SPECT)

a nuc med study performed by using a gamma camera to

acquire 2D images from multiple angles- reconstructed by computer to 3D dataset

Positron Emission Tomography (PET)

operate on a molecular level to produce 3D images; performed using a positron (positive electron) attached to a

targeting pharmaceutical

whats the most common target molecule in PET scans?

fluorodeoxyglucose (FDG)

what are oncologic PET scans used for?

diagnosis and treatment follow-

up of cancer

what are 2 advantages to nuclear medicine?

can locate hidden metastases

or to detect recurrence from a known tumor and produces less patient exposure to radiation

what is nuclear medicine mainly used for?

cardiopulmonary imaging and evaluating bones

artificial intelligence

intelligence (AI)

demonstrated by a machine

how has AI affected radiology?

has traditionally involved supervised

learning, a programmer or radiologist teaches the

computer

branching white lines in chest xrays are what?

blood vessels

why are bronchi mostly invisible on a normal chest xray?

they are very thin- walled, contain air, and surrounded by air

why do you also want to make sure you look at the costophrenic angle in a chest xray?

could be fluid there you wouldnt want to miss

what are points of a technically adequate chest xray?

can see the spine through the heart shadow, good inspriation (can count almost 10 ribs), no rotation, little magnification (because its a PA chest image), left hemidiaphragm is visible thourgh the heart

posterior ribs or anterior ribs..

easy on the eyes

posterior ribs

posterior ribs or anterior ribs..

tend to be oriented horizontally

posterior ribs

1 multiple choice option

posterior ribs or anterior ribs..

less distinct

anterior ribs

posterior ribs or anterior ribs..

angled downward

anterior ribs

1 multiple choice option

what are posterior ribs attached to?

thoracic vertebral body

what are anterior ribs attached to?

sternum or each other

what are the 2 layers of pleura?

parietal and visceral

both parietal and visceral pleura are routinely seen on a conventional radiograph t/.f

false

which are larger in size? lower or upper lobe vessels

lower

1 multiple choice option

all vessels taper gradually from ________ to __________

central to peripheral

what is visceral pleura attached to?

lungs

what forms the fissures?

visceral pleura folded on itself

small amount of fluid is present in pleural space between the visceral and parietal pleura t/f

true

parietal pleura lines inner chest wall but not normally attached to it t/f

true

lateral costophrenic angle

a sharp, deep sulcus present on both right and left side

retrosternal space

clear space behind the sternum

does the hila region have a discrete shadow

no

Vertebral bodies approximately _________ and ________ to each other

equal height and parallel

Posterior costophrenic angles are ______

sharp

why is the left hemidiaphragm not seen continuous from back to front?

heart obscures view

Major fissure and minor fissure frequently visible on the ________ view

lateral

whats the most frequent reason the retrosternal clear space is obscure?

adenopathy