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SMS-NLINVSimultaneous Imaging of Multiple Slices

Sebastian RosenzweigDiagnostic and Interventional Radiology

University Medical Center Göttingen

May 29, 2020

SMS-NLINV

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Motivation

[1] Uecker et al., Magn. Reson. Med. (2008)[2] Uecker et al., NMR Biomed (2010)

real-time imaging

NLINV

Regularized Nonlinear Inversion1,2

limited to single slice

SMS-NLINV

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Motivation

[1] Uecker et al., Magn. Reson. Med. (2008)[2] Uecker et al., NMR Biomed (2010)[3] Larkman et al., Magn. Reson. Med. ( 2001)

real-time imaginglimited to single slice

SMS

Simultaneous Multi-Slice3

NLINV

Regularized Nonlinear Inversion1,2

less data demandtime-consistent slices

SMS-NLINV

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Motivation

SMS-NLINV[1] Uecker et al., Magn. Reson. Med. (2008)[2] Uecker et al., NMR Biomed (2010)[3] Larkman et al., Magn. Reson. Med. ( 2001)

less data demandtime-consistent slices

real-time imaging

SMS

Simultaneous Multi-Slice3

NLINV

Regularized Nonlinear Inversion1,2

limited to single slice

SMS-NLINV

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Conventional Multi-Slice Imaging

[Figures] adapted from Rosenzweig, MA Thesis 2016

SMS-NLINV

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Conventional Multi-Slice Imaging

k-space reconstruction

Figures adapted from Rosenzweig, MA Thesis 2016

SMS-NLINV

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Conventional Multi-Slice Imaging

k-space reconstruction

k-space reconstruction

Figures adapted from Rosenzweig, MA Thesis 2016

SMS-NLINV

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Simultaneous Multi-Slice Imaging

k-space reconstruction

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SMS-NLINV

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Simultaneous Multi-Slice Imaging

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+

k-space reconstruction

SMS-NLINV

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Simultaneous Multi-Slice Imaging

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+

+

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k-space reconstruction

SMS-NLINV

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Simultaneous Multi-Slice Imaging

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k-space

SMS-NLINV

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Simultaneous Multi-Slice Imaging

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+

SMS-NLINV

k-space reconstruction

SMS-NLINV

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Optimization Problem

SMS-NLINV

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Optimization Problem

SMS-NLINV

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Optimization Problem

SMS-NLINV

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Optimization Problem

SMS-NLINV

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Optimization Problem

● solve for update in each Newton-step

● iterative update

● Tikhonov regularization

SMS-NLINV

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● non-linear formulation

● complementary k-space samples

Benefits

?

SMS-NLINV

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Cartesian | 2 slices

SMS-NLINVnon-linear reconstruction

(calibration-less)

difference toreference

difference toreference

N=12

[1] Uecker et al., Magn. Reson. Med. (2014)

kspace

ESPIRiT1linear reconstruction

(additional coil calibration)

SMS-NLINV

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Cartesian | 2 slices

difference toreference

difference toreference

[1] Uecker et al., Magn. Reson. Med. (2014)

kspace

N=4

SMS-NLINVnon-linear reconstruction

(calibration-less)

ESPIRiT1linear reconstruction

(additional coil calibration)

SMS-NLINV

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Radial | 3 slices

NLINV

undersampled (10x)fully sampled

... ...

slice

SMS-NLINV

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Radial | 3 slices

SMS-NLINVNLINV

aligned (10x)undersampled (10x)fully sampled

... ... ...

slice kz

SMS-NLINV

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Radial | 3 slices

SMS-NLINVNLINV

complementary (10x)aligned (10x)undersampled (10x)fully sampled

... ... ......

slice kz

SMS-NLINV

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Radial | 3 slices

SMS-NLINVNLINV

undersampled (10x)fully sampled

... ... ......

ky

kx

ky

kx

complementary (10x)aligned (10x)

kzslice

SMS-NLINV

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Temporal Regularization

SMS-NLINV

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Temporal Regularization

SMS-NLINV

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Temporal Regularization

penalize the difference to the previous frame

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SMS real-time MRI

5 spokes per partition & frame

3 slices & 29 framesper second

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Wrap Up

SUMMARY● joint estimation of

images and coils

LIMITATIONS● ~ 2 - 5 slices● problem size● SMS-FLASH study

OUTLOOK● SMS-bSSFP sequence● T1 mapping1,2

[1] Wang et al., submitted for publication to Magn. Reson. Med. (2020). [2] Wang et al., ISMRM 2020

➔ improved image quality➔ time-consistency➔ multi-slice real-time MRI

SMS-NLINV T1 mapping1,2

https://github.com/mrirecon/sms-nlinv

https://github.com/mrirecon/sms-nlinv

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