04 relajacion transversal

THOME

PHYSICAL PRINCIPLES

Signal Generation

THOME

nuclei, protons and spins

longitudinal relaxation T1

transverse relaxation T2

exitation and relaxation

relation between T1 and T2

signal generation

THOME

transverse relaxation T2

Spin - Spin relaxation

signal generation

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

ZBo

signal generationtransverse relaxation T2

Y

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

Signal

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

Signal

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

Signal

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

Signal

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

Signal

dephasing

signal generationtransverse relaxation T2

THOME

S

time

Free Induction Decay signal

FID

T2

signal generationtransverse relaxation T2

THOME

T2

S

T2

63%

definition T2:

the time that passes untill 63% of the original signal has been lost

time

signal generationtransverse relaxation T2

THOME

T2

S

T2*

time

signal generationtransverse relaxation T2*

Due to magnetic inhomegeneities the transverse relaxation is lost faster !! T2 T2*

THOME

X

Y

ZBo

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

transmitcoil

radiofrequencytransmitter

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

transmitcoil

radiofrequencytransmitter

180º

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

X

Y

ZBo

180º

signal generationtransverse relaxation T2

THOME

180º

refocusing pulse

signal generationtransverse relaxation T2

THOME

180º 180º

refocusing pulse

signal generationtransverse relaxation T2

THOME

T2 envelope

signal generationtransverse relaxation T2

THOME

in conclusion:

• T1 relates to magnetisation

• T2 relates to signal

signal generation

THOME

nuclei, protons and spins

longitudinal relaxation T1

transverse relaxation T2

excitation and relaxation

relation between T1 and T2

signal generation