Acceleration for all 2D & 3D anatomical contrasts, 100% coverage on all anatomies. Body[r]
(1)A li ti f f t i
Application of fast scanning
technique “compressed SENSE” on MR system Philips Ingenia 1.5T
Phan Anh Phuong; Nguyễn Công tiến; Nguyễn Văn Hòa;
Lê Văn Tài; Trần Duy Hưng; Nguyễn Tuấn Dũng; Lê Xuân Thanh Radiology center in Bach Mai hospital
Advantages of MRI
• Powerful imaging modality for clinical • Noninvasive examination of the body • does not use ionizing radiation
• High soft‐tissue characterization with flexible image‐contrast parameters
(2)Disadvantages of MRI
• Has been relatively slow compared to other imaging modalities such as CT
• Low speed, thus long examination times
• Limit spatial resolution and volumetric coverage • sensitivity to respiratory motion
The goals in MRI
(3)Compromises in MRI
The invention of fast MR Imaging strategies
• Fast Low Angle Shot (FLASH) • Fast Spin‐ Echo(FSE) Imaging • Echo‐Plana Imaging
• Since Late 1990s Parallel Imaging techniques were proposed
(4)Parallel Imaging
MRI questions.com
(5)0
‐
20
times
JPEG VS RAW
1
0
The concept of compressed sensing, which was originally
proposed in the early 2000s by Donoho and Candès
K - space transform in MRI
(6)Only centre and periphery of K - Space
TF
TF
(7)Compressed SENSE principle
The goal image Incoherent subsampling
Wavelet transform Denoising by threshold
Compressed SENSE principle
Wavelet
transform and
denoised saparsity Incoherent
undersampling
Non‐liner iterative
(8)Philips Compressed SENSE
(2D, 3D, 4D, all anatomies, all MRI sequences)
= =
SENSE + Compressed Sensing
(2D, 3D, 4D, all anatomies) (3D, body area)
Conventional sequences VS compressed SENSE
43% 400 600 800 T2_TSE_SAG _0.8X0.8X4 mm_3.33S T1_TSE_SA G_0.8X0.8X 4mm_3.36S CS_T2_TSE_SAG _0.8X0.8X4mm _2.02S CS_T1SAG_T SE_0.8X0.8X 4mm_2.00S T2_AX_TSE_0.8X0 8X4mm_3.36S CS_T2_AX_TSE_0.8 X0.8X4mm_2.07S
10.45s 6.09s
200 400
(9)CS_FLAIR_AX_FS_ 0.69x1.1_RE1.3_2.58S
CS_T2_TSE_AX_
0.6x0.75_1.42S_RE 1.5 TOF_CS SENSE_0.6x0.9_RE3_2.59S
7.39s 200 400 600 800 TIME NON_CS CS 32%
FLAIR AX_FS_0.69x1.1_3.50S T2_TSE_AX_0.6x0.75_2.31S TOF_SENSE_0.6x0.9_4.47S
11.08s
Application on Philips 1.5T Ingenia
(10)Application on Philips 1.5T Ingenia
CS_T1 3D_TSE_FS Sag_1.1.1mm_3:18s(CS=5)
Application on Philips 1.5T Ingenia
(11)` Increase resolution
T2_SAG_TSE_1x 1.35x4mm_59S
CS_T2_SAG_TSE_0.8x0.8X4mm_
59S_RE 1.6_FOV280mm
(12)Up to 50% acceleration
Acceleration for all2D & 3D anatomical contrasts, 100% coverageon all anatomies
Body
Brain Spine MSK
Vascular
Cardiac Breast Whole body
compatible
• 2D and 3D sequences • Fat saturation
• Dark fluid • Dixon • T1, T2, PD
(13)Drawback
• Cannot be used:
• EPI
• Multislice‐TSE with partial NSA is used( half scan) • Non‐Cartesian scans( multiVane )
• OMAR • spectroscopy
(14)Compressed SENSE- conclusion
• Faster imaging, higher system throughput • Image quality improvement is possible • Applicable in all anatomical regions • Work with almost 2D, 3D sequences
• Easier for breath hold/ faster for dynamic imaging • New high end study become possible
• New high‐end study become possible
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