# Sequences and Image Contrasts Flashcards

1
Q

the time between two 90 RF excitation pulses

A

repetition time (TR)

2
Q

the time between the 90 RF pulse and the peak of the signal in the receiver coil

A

echo time (TE)

3
Q

T1’s use __ TRs and ___ TEs

A

T1= short TR and short TE

4
Q

What is the normal TR range for T1 images?

A

350-700 MS

5
Q

The ___ the TR the more T1 weighted it will be.

Shorter/longer

A

shorter TR = more T1

6
Q

What is the normal range for TE on a T1 image?

A

10-30 (think SHORT TE for T1)

7
Q

ON a T1 image

Water is ___

dark or bright?

A

dark

8
Q

On a T1 image

Fat is ___

dark or bright?

A

bright

9
Q

What are another name for a T1 image?

A

spin lattice

10
Q

Is T1 better for ANATOMY or PATHOLOGY?

A

ANATOMY!! think A comes first in the alphabet…A for T1

11
Q

PD stands for proton density. These sequences will have a ____ TR and a ___ TE?

short / long

A

PD= Long TR and Short TE

12
Q

What is the normal TR range for a PD image?

A

1600-4000

13
Q

What is the normal range for TE on a PD image

A

10-30

14
Q

a proton density image is basically canceling out both T1 and T2 properties.

A

True. We want to minimize both T1 and T2. PD is neither T1 or T2.

15
Q

T2s use a ___ TR and a ___ TE.

A

Long TR + Long TE = T2

16
Q

What is the normal TR for T2 images?

A

2000-6000

17
Q

WHat is the normal TE of a t2?

A

80-120

18
Q

Does the TE or the TR control T2 weighting?

A

TE controls T2

19
Q

Increasing the T2 weighting of an image can be done by increasing the ___

TR or TE?

A

TE

20
Q

On T2s, fluid is ___

bright or dark?

A

t2= BRIGHT fluids

21
Q

On T2s, fat is typically ___

dark or bright?

A

T2- fat is dark

22
Q

When we are scanning an inversion recovery sequence, what is the contrast controlled by?

The TR the TE or the TI?

A

All three! Inversion recovery is controlled by TE TR and TI (inversion time)

23
Q

The T1 of adipose tissue is shorter than the T1 of water

True or False

A

True

24
Q

What does STIR stand for?

A

Short TI inversion recovery

25
Q

STIRs use specific timing to suppress the signal from fat. True or False?

A

TRUE, that’s why they are so dark.

26
Q

a spin echo pulse sequence preceded by a 180 RF pulse is what type of sequence??

A

STIR

27
Q

Why with a STIR do we do the 180 RF Pulse?

A

it inverts the starting magnetization which then returns to its equilibrium according to T1 relaxation.

28
Q

During a STIR, Fat
will reach its null point faster than white matter, grey matter, water or edema, and
so an image of these structures can be generated

A

True

29
Q

make the TI long and
you have the FLAIR pulse sequence, which suppresses signal from fluid

True or False

A

True

30
Q

Enabling Driven Equilibrium (DRIVE: Philips) will enable the operator to increase TR
and preserve contrast

A

FALSE

Enabling Driven Equilibrium (DRIVE: Philips) will ENABLE the operator to reduce TR
and preserve contras

31
Q

When does the presaturation pulse typically occur?

prior to excitation or after the excitation pulse?

A

prior

32
Q

Fat suppression techniques suppress based on the precessional frequency of ___

A

Fat

33
Q

90 RF followed by 180 RF is what type of pulse sequence?

Spin echo, fast spin echo, inversion recovery or a gradient echo.

A

Spin Echo

34
Q

90 RF followed by a train of 180 RF pulses is what type of pulse sequence?

Spin echo, fast spin echo, inversion recovery or a gradient echo.

A

fast spin echo.

35
Q

a 180 RF followed by a 90 RF is what type of pulse sequence?

Spin echo, fast spin echo, inversion recovery or a gradient echo.

A

inversion recovery

36
Q

variable RF followed by gradient to produce echo

this is what type of pulse sequence?? Spin echo, fast spin echo, inversion recovery or a gradient echo.

A

37
Q

What are examples of extrinsic contrast parameters ( ones that MR techs can adjust to alter image)

A

TR, TE, flip angle, TI and ETL

38
Q

What are examples of intrinsic paramters ( specific to tissue and cannot be changed by MR tech)

A

ADC, T1 AND T2 times, specific proton density, and flow

39
Q

What are some structures that will ALWAYS appear black on an MRI image?

A

air, tendons, ligaments, metallic susceptibility and cortical bone.