Lecture 5: Radiographic Interpretation

in regards to radiation physics, which setting on the machine can increase the speed electrons trave from the cathode to anode?

kVp

what does the L indicate?

tells the reader this is a left lateral view

what does the R indicate?

tells the reader this is a right lateral abdomen, it’s also positioned with cranial to the reader’s left

what is the proper orientation for lateral view?

cranial to left and dorsal at top of image

what is properly positioned lateral view?

cranial to left, dorsal at the top of the image, caudal to the right

how should medial-lateral projection be oriented?

with cranial or dorsal to the readers left

ventrodorsal (VD)/dorsoventral (DV) views

positioned with cranial at the top of the image and the patients right on the readers left

what view is this?

VD/DV

how should this radiograph be adjusted?

rotate to the right and flip cranial and caudal

radiolucent materials will show up

more black

radiopaque materials will show up

more white

what material is the most radiolucent?

air

what material is the most radiopaque?

metal

what is 1

gas/air

what is 2

soft tissue

what is 3

fat

what is 4

bone/mineral

what is the opacity the arrow is pointing at?

soft tissue

what are Roentgen signs?

size, shape, number, location, margination, opacity

magnification occurs due to

the distance between the structure and the receiver → can reduce detail of image

distortion occurs when

the object and receiver are not parallel

summation

opacity created that does not represent a structure that is present within the patient

where is summation common?

the kidneys on lateral radiograph where the intersection of the caudal pole of the right kidney with the cranial pole of the left kidney

border effacement/silhouette sign

• two structures in contact with each other that has the same opacity

• loss of margin distinction

underexposed images

image is too bright so usually kVp or mAs is too low

overexposed images

image is too dark so usually kVp or mAs is too high

contrast

links directly to the differing of opacities based on varying degrees of x-ray beam absorption

ability of an x-ray beam to penetrate tissue depends on

its energy

the x-ray beams energy directly ties to a

varying kVp and a stable mAs

why does higher kVp give less contrast?

because more x-rays are transmitted through the patient to the plate

lower kVp allows for

higher contrast

detail

spatial resolution or sharpness

detail can be influenced by

exposure factors, matrix of IP, software, monitor, reader’s visual acuity

pixel

picture element

dicom

digital imaging and communications in medicine

pacs

picture archiving and communicating system