Week 1 Video part 1 of Concepts of cross sectional anatomy

Question 1

Planes of sectional anatomy

Answer 1

Question 2

Image orientation

Answer 2

Patient always opposite

Question 3

CT Computed Tomography

Answer 3

Axial one image (CAT scan)- singularly
Helical (spiral scan)- volume

Question 4

CT Scanner

Answer 4

Question 5

CT Scan Helical

Answer 5

Circular x-ray and patient moves through gantry. faster , hold breath once.
Not as clear compared to axial. Not as shape

Question 6

CT window/level changes

Answer 6

to the anatomical structures. changes how see. can black out areas. color level
is called windowing.

Question 7

CT can use oral and IV contrast Enhancement

Answer 7

oral for stomach and intestine and IV for vascular. To help
visualualize structures better.

Question 8

CT plane

Answer 8

Can change plane to see coronal/sagital instead of just axial. Give the ability to see above and below. Can also change to an oblique plane. This is the benefit of an helical scan

Question 9

CT 3D Reconstruction

Answer 9

Setup to look at all three planes.

Question 10

CT 3D Reconstruction

Answer 10

Question 11

Image Acquisition

Answer 11

Matrix, Pixel, Voxel

Question 12

Image Acquisition matrix

Answer 12

higher rows and column will create higher resolution in image but at a price of media storage space (data)

Question 13

Voxel

Answer 13

A voxel is a measurement of volume in a structure that is to be imaged. Each voxel represents a defined volume, and can be localized by coordinates on a three-dimensional grid. Both CT and MRI scanners image a slab of tissue and describe it in a two-dimensional image on the computer screen.

Question 14

Pixel

Answer 14

Pixel: Two dimensional picture element that makes up the matrix. Each pixel represents a CT number and is the building block of the matrix and image. Prospective data: An image automatically reconstructed from the scan data.

Question 15

Matrix

Answer 15

A CT scan image matrix is a square arrangement of pixels, or picture elements, in columns and rows. The size of the matrix can range from 256 x 256 to 1024 x 1024 pixels, but the most common size is 512 x 512, which is made up of 262,144 pixels

Question 16

Image quality Spatial Resolution

Answer 16

Larger the matrix the better the spacial resolution. Higher detail then. Small structure can provide a better image. Low resolution may not be able to see well

Question 17

Image quality Noise

Answer 17

Not real information. Electric noise created by electronic interferance. Voltage irregularities. A replacement part like metal in a person can cause streak artifacts.

Question 18

Image quality Distortion

Answer 18

unusual anatomy can be cause by a person moving, cough, moved foot during imaging. this will cause a distortion.

Question 19

Image quality filters

Answer 19

smoothing- can reduce voxel by averaging hense will smooth image. used on soft tissue.
edge enancement- to improve visibilty to increase edge sharpness.

Question 20

Image quality Partial volume averaging

Answer 20

Partial volume ave- slice thickness . voxel with anatomy in two voxel containing???
AI answer- Partial volume averaging (PVA) is a CT artifact that occurs when different tissues with different absorption values are in the same CT voxel. This results in beam attenuation that is proportional to the average value of the tissues

Question 21

Image quality Artifacts

Answer 21

Streak, motion, beam-hardening, ring, bloom, metallic

Question 22

Image analysis ROI (region of interest)

Answer 22

x-ray photon intensity is a hounsfield unit which helps identify bone which would have a high number at 1000. Water is standard which is 0. Air is -1000

Question 23

Hounsfield unit (HU)

Answer 23

A Hounsfield unit (HU), also known as a CT unit, is a quantitative measurement of radio density used by radiologists to interpret computed tomography (CT) images
Fat will have a low HU.
Examples of HU values for different types of tissue:
Air: –1,000 HU
Water: 0 HU
Bone: 1,000 HU
soft tissue = 400
Grey matter: +37 to +45 HU
Lung: –700 to –600 HU
Silver foreign objects: +17,000 HU

Question 24

Image analysis pitch

Answer 24

Pitch is the rotation speed of the x-ray aournd the person in relation to the table speed through the gantry.