Beginning to understand medical imaging

Question 1

What are the 4 planes of the body?

Answer 1

Median
sagittal
Frontal (coronal)
Transverse

Question 2

Define median

Answer 2

is a plane that divides the body into a left and right half- 90 degrees running down the body.

Question 3

Define Sagittal

Answer 3

Anatomical plane that divides the body into left and right sections

Question 4

Define Frontal

Answer 4

divides the body into anterior and posterior. See structures anterior and posterior.

Question 5

Define transverse

Answer 5

transaxial or axial- divide the body into superior and inferior.

Question 6

What is radiopaque?

Answer 6

(white/light)- structures that attenuate the beam to a large extent- planar of fluoroscopy

Question 7

What is radiolucent?

Answer 7

(black/dark)- structures that attenuate the beam to a small extent- planar of fluoroscopy

Question 8

What is attenuation?

Answer 8

reduction of the intensity of an x-ray beam

Question 9

The basics of planar imaging

Answer 9

Hand x-ray- position hand flat on the recording medium-projection is PA but is instead called dorsa Palma.

Important to position patients in a standard way- looking at images is like spotting the difference which is why images need to be taken in a standard way. If done differently it needs to be specified.

Importance of standardization- Look at images and compare images to spot abnormalities.

Equipment standardization is important- eg angles of the beam

Planar imaging- 3d anatomy represented as 2d images

Question 10

Features to note on an x-ray image

Answer 10

Patients name
Date of examination
Anatomical marker
Legends- other info eg supine and erect
Exposure indication- does vary from manufacturer to manufacturer.
When more than one projection taken view information on all images to gather evidence.

Question 11

Fluoroscopy

Answer 11

-Use of continuous/pulsed x ray imaging

-Produces real time imaging

-Used in theatres and interventional work\contrast media can be used to visualise structures not normally seen.

Question 12

The basics of CT imaging

Answer 12

Ct uses x ray
Tissues can appear similar in shades to x ray.
3 dimensional structures displayed in the form of cross-sectional slices
Axial (direct), coronal and sagittal (through reconstruction)
Can produce 3d reconstructed images.
Ability to display more Information with structures with similar attenuating properties
See more tissues- much more sensitive and can distinguish between various tissues
Produce cross sectional images in all 3 planes
See everything as separate structures, no overlapping.
Image produced in axial way, and get computer to slice them.
A reconstructed image has been created in that plane.

Question 13

The basics of MRI imaging

Answer 13

3d anatomy is presented in the form of thin cross-sectional slices
Greater degree of sensitivity, see soft tissue structures a lot better
No bony artefacts
Allows the production of slices in any given plane, coronal, sagittal, axial as well as oblique.

Question 14

The basics of ultrasound imaging

Answer 14

Sound reflected at tissues interphases between tissue
Some sound may pass through and get reflected at other tissue interphases
Some solid structure do not allow sound to pass through and as a result shadowing may be present.
Strongly reflected signals appear white hyperechoic
Structures which do not reflect sound appear black anechoic (without echo)
Weak signals appear dark hypoechoic