chap 6 accelerated k-space filling - universitetet i oslo · chap 6 accelerated k-space filling –...

CHAP 6 Accelerated k-space filling – Rapid Acquisition of repeated echoes (RARE / FSE,

TSE)

– Echo Planar Imaging (EPI)

– Joy riding in k-space

CHAP 7 Magnetization preparation – Principles

– Selective tissue suppression

– Influence of the excitation pulse on magnetization curve

CHAP 8 Image quality, SNR, CNR – Introduction

– K-space filling strategies

Accelerated k-space filling

Simple SE sequence

TE

TR

FID SE

90°

180°

T2

Dead time

90°

Secondexcitation

Rapid Acquisition with Relaxation

Enhancement (RARE) / FSE or TSE

1st echo90°

180° 180° 180°

TE1TE2

TE3TR

90°

180°

2nd echo 3rd echo 1st echo

Secondexcitation

FSE/TSE k-space filling

TSE – Effective Echo Time

TSE – echo modulation

TSE – echo modulation

TSE – different profile orders

•

•

TSE / Linear k-space filling

TSE / Centric k-space filling

TSE

ETL=11 ETL=256

CHAP 6 Accelerated k-space filling – Rapid Acquisition of repeated echoes (RARE / FSE,

TSE)

– Echo Planar Imaging (EPI)

– Joy riding in k-space

CHAP 7 Magnetization preparation – Principles

– Selective tissue suppression

– Influence of the excitation pulse on magnetization curve

CHAP 8 Image quality, SNR, CNR – Introduction

– K-space filling strategies } } } } } } }

GRE-EPI

GRE-EPI

SE-EPI

Artifacts in EPI

Artifacts in EPI

Eddy Current effect

CHAP 6 Accelerated k-space filling – Rapid Acquisition of repeated echoes (RARE / FSE,

TSE)

– Echo Planar Imaging (EPI)

– Joy riding in k-space

CHAP 7 Magnetization preparation – Principles

– Selective tissue suppression

– Influence of the excitation pulse on magnetization curve

CHAP 8 Image quality, SNR, CNR – Introduction

– K-space filling strategies

Spiral Imaging

Spiral Imaging

CHAP 6 Accelerated k-space filling – Rapid Acquisition of repeated echoes (RARE / FSE,

TSE)

– Echo Planar Imaging (EPI)

– Joy riding in k-space

CHAP 7 Magnetization preparation – Principles

– Selective tissue suppression

– Influence of the excitation pulse on magnetization curve

CHAP 8 Image quality, SNR, CNR – Introduction

– K-space filling strategies

TR*(T12-T1

1)/(T11T1

2)

Use of magnetization preparation

Inv-GRE (MPRAGE) / Linear

Inv-GRE (MPRAGE) / Centric

CHAP 6 Accelerated k-space filling – Rapid Acquisition of repeated echoes (RARE / FSE,

TSE)

– Echo Planar Imaging (EPI)

– Joy riding in k-space

CHAP 7 Magnetization preparation – Principles

– Selective tissue suppression

– Influence of the excitation pulse on magnetization curve

CHAP 8 Image quality, SNR, CNR – Introduction

– K-space filling strategies

Selective tissue suppression

Example of brain tumour

CHAP 6 Accelerated k-space filling – Rapid Acquisition of repeated echoes (RARE / FSE,

TSE)

– Echo Planar Imaging (EPI)

– Joy riding in k-space

CHAP 7 Magnetization preparation – Principles

– Selective tissue suppression

– Influence of the excitation pulse on magnetization curve

CHAP 8 Image quality, SNR, CNR – Introduction

– K-space filling strategies

Look-Locker sequence

Sequence overview