Scan Principles Image Contrast/Weighting*

Question 1

A sequence with a _________ TR and a _________ TE will exhibit T1 weighting.

Answer 1

short; short

Question 2

Which of the following statements is TRUE regarding spin echo sequences?

Answer 2

T1 contrast is maximized with short TR’s

Question 3

What is wrong with a T2 weighted, fast spin echo image that has a 1.1 second TR and an 90 millisecond TE?

Answer 3

The TR does not sufficiently minimize the T1 weighted contrast

The TR of 1100 ms is not long enough for T2 weighting

Question 4

Tissues with _______ are bright on T1 weighted spin echo scans and tissues with _________ are bright on T2 weighted spin echo scans.

Answer 4

short T1 times; long T2 times

Question 5

Enabling Driven Equilibrium will enable the operator to:

Answer 5

TE

The longer the TE, the more T2 weighting an image will exhibit.

Question 6

What determines the amount of T1 weighting in an image?

Answer 6

TR

Question 7

To produce an image based on differences in T1, the time interval between 90° excitation pulses should be:

Answer 7

Short

Question 8

A sequence with a _________ TR and a _________ TE will exhibit PD weighting.

Answer 8

Long; short

Question 9

A sequence with a _________ TR and a _________ TE will exhibit T2 weighting.

Answer 9

Long; long

Question 10

A T2 weighted image will have a repetition time (TR) in the range of:

Answer 10

2000 - 6000 ms

Question 11

A T2 weighted image will have an echo time (TE) in the range of:

Answer 11

80 - 120 ms

Question 12

A T1 weighted image will have a repetition time (TR) in the range of:

Answer 12

350 - 700 ms

Question 13

A T1 weighted image will have an echo time (TE) in the range of

Answer 13

10 - 30 ms

Question 14

A proton density weighted image will have a repetition time (TR) in the range of:

Answer 14

1600 - 4000 ms

Question 15

A proton density weighted image will have an echo time (TE) in the range of:

Answer 15

10 - 35 ms

Question 16

Water is dark and fat is bright in:

Answer 16

T1 weighted images

Question 17

Which of the following parameter combinations would yield the most T2 weighted image?

Answer 17

3500 TR, 120 TE

Question 18

Which of the following parameter combinations would yield the most T1 weighting?

Answer 18

350 TR, 15 TE

Question 19

Which of the following statements is FALSE?

Answer 19

T1 weighting is adjusted with short TE’s

Question 20

Water is hyperintense and fat is typically dark in:

Answer 20

T2 weighted images

T2 weighted images provide bright signal from fluids and fat is typically dark

Question 21

Short TR, short TE are the parameter requirements

Answer 21

Transverse magnetization

T1 relaxation time is the recovery of 63% longitudinal magnetization of a specific tissue.

Question 22

All of the following are properties of T2 weighting EXCEPT:

Answer 22

Flip angle controls contrast

Contrast is controlled by TE in a T2 weighted sequence.

Question 23

All of the following are true EXCEPT:

Answer 23

Gradient echo — 90° RF followed by 180° RF

Gradient echo lacks 180° RF pulses

Question 24

T1 is useful for __________, whereas T2 is utilized for depicting __________.

Answer 24

Anatomy; pathology

T1 is useful for anatomy, whereas T2 is utilized for depicting pathology(edema).

Question 25

All of the following are examples of INTRINSIC contrast parameters in tissues EXCEPT:

Answer 25

TR

Intrinsic parameters in tissues are those that are specific to each tissue, inherent, and cannot be changed, such as ADC, T1/T2 time, specific proton density, and flow.

Question 26

All of the following are examples of EXTRINSIC contrast parameters EXCEPT:

Answer 26

T1 time

Extrinsic contrast parameters are those that the MR technologist can adjust to alter the image

Question 27

Structures that will always appear black on an MR image include all of the following EXCEPT:

Answer 27

CSF

Question 28

Presaturation pulses typically occur:

Answer 28

Prior to the excitation pulse

Presaturation pulses typically occur prior to the excitation pulse.

Question 29

Increasing the TE in a spin echo pulse sequence:

Answer 29

Enables more T2 information in the image

Increasing the TE in a spin echo pulse sequence enables more T2 information in the image.

Question 30

In an inversion recovery sequence, image contrast is controlled by:

Answer 30

All of the above

In an inversion recovery sequence, image contrast is controlled by TR (repetition time), TE (echo time) and TI (inversion time)

Question 31

Chemical or spectral fat suppression techniques suppress fat signal based on the:

Answer 31

Precessional frequency of fat

Chemical or spectral fat suppression techniques suppress fat signal based on the precessional frequency of fat.

Question 32

Which of the following sets of parameters would show edema as hyperintense?

Answer 32

4000 TR, 90 TE

T2 weighted sequences (long TR – >2000 and long TE >80) will yield hyperintense(bright) signal from fluid (edema

Question 33

As the TR increases the amount of T1 weighted contrast ___________.

Answer 33

Decreases

As the TR increases the amount of T1 weighted contrast decreases

Question 34

A Proton Density weighted image has a TR that is long to _____________, and a TE that is short to _____________.

Answer 34

Minimize T1 contrast; minimize T2 contrast

A Proton Density weighted image has a TR that is long to minimize T1 contrast, and a TE that is short to minimize T2 contrast, yielding an image that is neither T1 nor T2.