final

Question 1

the initial information leaving a digital image receptor/receiver is a

Answer 1

electrical signal

Question 2

what factor would produce a digital image with the highest spatial resolution

Answer 2

increased matrix size

Question 3

in the context of a digital matrix, 1024 x 1024 refers to

Answer 3

the number of pixels in the matrix

Question 4

T/F: individual pixels in digital imaging are normally invisible to the unaided eye

Answer 4

true

Question 5

increasing the field-of-view will have what effect on the pixel size ?

Answer 5

increased pixel size

Question 6

the total number of brightness levels that can be produced by the digital system

Answer 6

bit depth

Question 7

will a 12-bit system or a 8-bit system have the highest contrast resolution

Answer 7

12 bit system

Question 8

an 8 bit radiograph system is capable of displaying how many shades of gray?

Answer 8

256 shades

Question 9

what change will increase the contrast resolution of a imaging system

Answer 9

increased bit depth

Question 10

quantization is the process through which

Answer 10

detector readings are converted to specific brightness levels

Question 11

the gray scale of an image is affected by the

Answer 11

bit depth

Question 12

where does quantization take place during image processing

Answer 12

in the analog-to-digital converter

Question 13

the smallest signal difference that can be detected and displayed by the imaging system is called

Answer 13

contrast resolution

Question 14

image signal can be increased with what parameter changes ?

Answer 14

• increasing slice thickness
• decreasing echo time
• increasing repetition time

Question 15

prescribing a small slice thickness causes

Answer 15

decreased signal to noise ratio

Question 16

increasing the matrix size has what effect on signal to noise ?

Answer 16

decreased signal to noise

Question 17

how does decreasing TR affect the SNR of an MRI image

Answer 17

decreased SNR

Question 18

compared to a 128 x 128 matrix, a 512 x 512 matrix will result in

Answer 18

decreased SNR

Question 19

image noise can be decreased by which parameter adjustments

Answer 19

• reducing bandwidth
• using surface coils

Question 20

an MRI image with high spatial resolution was most likely created using which parameter

Answer 20

large matrix size

Question 21

low signal to noise ratio can be the effect of

Answer 21

large matrix size

Question 22

increasing the matrix size will result in what?

Answer 22

increased spatial resolution
decreased SNR

Question 23

an MRI image demonstrating low spatial resolution might be the result of

Answer 23

large pixel size

Question 24

modifying the imaging parameters to use an increased bandwidth has what effect on the MRI image

Answer 24

decreased SNR

Question 25

decreasing the matrix size has what effect on SNR

Answer 25

increased SNR

Question 26

using large slice thickness causes

Answer 26

decreased spatial resolution

Question 27

concerning SNR, the use of a localized coil has what effect on the image

Answer 27

increased SNR

Question 28

compared to a 1.5T, a 3T will produce

Answer 28

increased SNR

Question 29

how does increasing voxel volume affect spatial resolution

Answer 29

decreases spatial resolution

Question 30

image noise can be decreased by which parameter adjustments

Answer 30

- reducing bandwidth - using surface coils

Question 31

the difference in signal intensity compared to the background noise

Answer 31

SNR

Question 32

the number of bits per pixel available in the system

Answer 32

contrast resolution

Question 33

low signal to noise ratio can be the effect of

Answer 33

large matrix size

Question 34

an increased echo time (TE) usually causes

Answer 34

decreased SNR

Question 35

a decreased echo time (TE) usually causes

Answer 35

increased SNR

Question 36

the MRI of the breast increases visibility of vascular structures using a process called

Answer 36

maximum intensity projection (MIP)

Question 37

a scan is performed to evaluate the vascular supply to an acute cerebral infarct. After acquiring pre & post contrast images, what post processing technique can be used to remove non vascular structures from the images

Answer 37

digital subtraction

Question 38

a radiologist request axial images of a stroke sequence initially acquired in the coronal plane, what post processing technique is necessary to fulfill this request?

Answer 38

multiplanar reconstruction (MPR)

Question 39

apparent diffusion coefficient (ADC) mapping is derived from what image sequence?

Answer 39

diffusion weighting images (DWI)

Question 40

what variables can be changed in a mulipalnar reconstruction ?

Answer 40

- slice gap - slice thickness - plane orientation

Question 41

when performing a MIP which of these tissues is most likely to be displayed on the pixel

Answer 41

high signal tissue