Fundamentals of Fundamentals of NNuclear uclear MMagnetic agnetic RResonanceesonance

Nuclear Magnetic Resonance (Nuclear Magnetic Resonance (NMRNMR) : ) : discovered by F. Block and E. Purcell in 1946discovered by F. Block and E. Purcell in 1946• Standard spectroscopic techniqueStandard spectroscopic technique

NMR ImagingNMR Imaging : P. Lauterbur(1973), P. Mansfield : P. Lauterbur(1973), P. Mansfield (1973), and R. Damadian(1971).(1973), and R. Damadian(1971).

IntroductionIntroduction

Angular MomentumAngular Momentum ：： TypeType ：：

Orbital Orbital SpinSpin

Nuclear spinNuclear spin ；； II The spin of unpaired neutrons or protons.The spin of unpaired neutrons or protons.1.1. I = 0I = 0 ；； nuclei with even numbers of protonnuclei with even numbers of proton

s and neutron.s and neutron.2.2. I = ± (1/2)nI = ± (1/2)n （ （ n is an integer n is an integer ）；）； Net nuclear angular momentum

vmrLa La ： angular momentumm ： massv ： velocity

體內各核種的相對靈敏度體內各核種的相對靈敏度

spinspinr r /2/2ππ

(MHz/T)(MHz/T)自然產率自然產率

((%)%) 體內含量體內含量 相對靈敏度相對靈敏度

11HH 1/21/2 42.5842.58 99.9899.98 100M100M 11

1313CC 1/21/2 10.7110.71 1.1081.108 10mM10mM 33×10×10-3-3

1414NN 11 3.083.08 99.6399.63 10mM10mM 22×10×10-7-7

1919FF 1/21/2 40.0540.05 100100 10mM10mM 99×10×10-5-5

2323NaNa 3/23/2 11.2611.26 100100 80mM80mM 11×10×10-3-3

3131PP 1/21/2 17.2317.23 100100 10mM10mM 44×10×10-5-5

3939KK 3/23/2 1.991.99 93.193.1 45mM45mM 11×10×10-4-4

磁偶極矩磁偶極矩 (Magnetic Dipole Momen(Magnetic Dipole Moment)t)

磁偶極矩磁偶極矩 (( 磁矩磁矩；； MM))質子自旋產生磁矩質子自旋產生磁矩

rIM r : 旋磁比 (gryomagnetic ratio)I : 核自旋 (nuclear spin)

11HH 、、 1313CC 、、 1919FF 、、 2323NaNa 、、 3131PP

Larmor equationLarmor equation

Larmor frequencyLarmor frequency ：： ωω

1.5 Tesla 下氫原子核的旋進頻率為 63.866MHz

0B

T1 curveT1 curve

T2 decay curveT2 decay curve

Image CharacteristicsImage Characteristics

SNRSNR ResolutionResolution TimeTime Relaxation EffectsRelaxation Effects Trade OffsTrade Offs

MRI ArtifactsMRI Artifacts Chemical Shift Artifacts Aliasing Black Boundary Artifacts Gibbs or Truncation Artifacts Zipper Artifacts Phase-encoded Motion Artifacts Entry Slice Phenomenon Slice-overlap Artifacts Magic Angle Effects Moire Fringes RF Overflow Artifacts Central Point Artifact Susceptibility Artifacts Zero-fill Artifact (Zebra Artifact)

Chemical Shift Artifacts Chemical Shift Artifacts

Aliasing or "Wrap-around " Aliasing or "Wrap-around "

Electronics and Data ProcessingElectronics and Data Processing

CoilCoil

AngiographyAngiography

DSADSA

MRAMRA

CT angiographyCT angiography

3D TOF MRA MIP SSD3D TOF MRA MIP SSD

3D CE-MRA MIP SSD3D CE-MRA MIP SSD

DWI and PWIDWI and PWI

Diffusion weighted imagingDiffusion weighted imagingPerfusion weighted imagingPerfusion weighted imaging

MRSMRS

Coronary MRACoronary MRA

Breath-hold 3D CE-MRA of coronary arteries.Breath-hold 3D CE-MRA of coronary arteries.

(a) 2D (b) 3D

MR Breast ImagingMR Breast Imaging

AbdomenAbdomen

Flash T1Flash T1 Haste T2Haste T2

MRAMRA

3D CE-MRA3D CE-MRA

SMV and Portal veinSMV and Portal vein

MRCPMRCP

MRCPMRCP

MRCPMRCP

kidneyskidneys

Renal a.Renal a.

3D CE-MRA

MRUMRU

MRUMRU

rare

3D CE-MRA

AngiographyAngiography

3D CE-MRA

SummarySummary

Non-ionizing radiationNon-ionizing radiationMinimally invasive Minimally invasive （（ or non-invasiveor non-invasive ））Excellent soft-tissue contrastExcellent soft-tissue contrast Imaging in any arbitrary planeImaging in any arbitrary planeFunctional imagingFunctional imaging