#457Sweep Imaging with Fourier Transform

(SWIFT) in Breast Cancer

Curtis A. Corum, Andrew Babcock, Djaudat Idiyatullin,Angela L. Styczynski-Snyder, Diane Hutter,

Lenore Everson, Michael Nelson, and Michael Garwood

University of Minnesota, Minneapolis, MN, United States

ISMRM 2012, Wed. May 9

#457 Breast SWIFT, Curt Corum

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Declaration of Relevant Financial Interests or Relationships

Speaker Name: Curtis A. Corum

I have the following relevant financial interest or relationship to disclose with regard to the subject matter of this presentation:

Dr. Corum is entitled to sales royalties under an agreement between the University of Minnesota and GE Healthcare, which is developing products related to the research described in this paper. The University of Minnesota also has a royalty interest in GE Healthcare. These relationships have been reviewed and managed by the University of Minnesota in accordance with its Conflict of Interest policies.

ISMRM 2012, Wed. May 9

#457 Breast SWIFT, Curt Corum

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Breast MRI

While many MRI sequence types are sometimes indicated in Breast MRI the two main image sets usually desired are:

High spatial resolution pre and post-contrast T1 weighted images (and

subtractions) for morphological assessment (circumscribed vs spiculated, homogeneous vs heterogeneus enhancing, etc.)

High temporal resolution dynamic contrast enhanced (DCE) T1

weighted image series with at least 1 min temporal resolution for contrast kinetics (uptake vs washout)

Emerging standard of care utilizes semi and fully-quantitative pharmacokinetic modelling, with active research in improving models

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#457 Breast SWIFT, Curt Corum

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SWIFT

SWeep Imgaing with Fourier Transform

Simultaneous interleaved excitation and acquisition

3D Radial Sampling (Halton sequence)

PD or T1 weighted

Smooth Gradient Update (Quiet) robust against motion, eddy currents, and system timing

ISMRM 2012, Wed. May 9

#457 Breast SWIFT, Curt Corum

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SWIFT

SWeep Imgaing with Fourier Transform

Simultaneous interleaved excitation and acquisition

3D Radial Sampling (Halton sequence)

PD or T1 weighted

Smooth Gradient Update (Quiet) robust against motion, eddy currents, and system timing

ISMRM 2012, Wed. May 9

#457 Breast SWIFT, Curt Corum

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SWIFT Timing

SWIFT has extremely short dead timeOn the order of 2-6 μs

Sensitive to fast relaxing spinsPreserves signal from off resonant spins

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4 T SWIFT Breast Coils

SWIFT compatible Dual Breast Coil4 ch Transmit/Receive, 4 T

UMN Physics Machine Shop, Peter NessCMRR Gregor Adriany, Carl Snyder

Now in imaging testing

Modified Single Breast Coils2 ch Transmit/Receive, 4 T

CMRR Carl SnyderHelmut Merkle (now at NIH)

Currently in use

ISMRM 2012, Wed. May 9

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Halton View Order

Pseudo Random 3d radial view-orderingSorted for smooth gradient transitionFull sphere coverage every 512 viewsDesigned for View Sharing and CS reconstruction

ISMRM 2012, Wed. May 9

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Goals

Implement SWIFT based protocol for Breast MRI

SWIFT compatible (no short T2 background from polymers, fast switching and/or ring-down times) transcieve coil(s)

Demonstrate high temporal resolution SWIFT DCE imaging

Demonstrate high spatial resolution morphological pre and post contrast imaging from same scan data

Scan an initial cohort of patient volunteers

ISMRM 2012, Wed. May 9

#457 Breast SWIFT, Curt Corum

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SWIFT Protocol

2 min shimming, pre-scan, scout

20 sec SWIFT pre-scans, phase reference and gain

1-2 min SWIFT FOV check, FS

(2-4 min) (optional) Double Angle Method GRE B1 map

(2-4 min) (optional) SWIFT Variable Flip Angle T1 map

2-6 min SWIFT DCE FS, pre-contrast (MagnavistTM 0.1 mM/kg at 2 cc/s)

6 min SWIFT DCE FS post-contrast,

(optional) further SWIFT test scans

11.33 min Minimum total time

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4 T SWIFT ParametersTR 4.4 ms, 62 kHz, 4.1 ms HS1, Flip 8-16 deg, 256 points

Fat Suppression (FS)1/8 views, 4 ms Gauss, Flip 120 deg, offset -625 Hz

3d Radial Isotropic Vieworder

Sorted Halton** sequence, 512 views per k-space sphere

128 full spheres per 4.5 min acquisition (6 min with FS)

65,536 views total before restarting

Gridding based reconstruction

Sliding window reconstruction for DCE, 6 sec frames

* 10 ms HS4 R20 pulse for dual fat and silicone suppression

** Wong TT, Sampling with Hammersley and Halton Points,J Graph Tools archive, Volume 2 , Issue 2, 1997., Chan RW et al., MRM 2010.

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Case FA

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Case mass like DCIS

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Case IDC

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Ongoing Study...

We have now recruited 12 patients and have 8 successful sessions3 of the incompletes were due to last minute exclusionsone due to scanner failure

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Conclusions

SWIFT can produce high temporal resolution DCE and high resolution morphological data from the same scan data

Work in progress....

Model based evaluation of DCE data

Compressed Sensing reconstruction

Case reviews and search for novel contrast (short T2)

Continue recruiting patients....

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Acknowlegdements

We gratefully acknowledge NIH R21 CA139688, P41 RR008079, S10 RR023730, S10 RR027290,and the Minnesota Medical Foundation 3932-9227-09for grant support.

Thanks to physicians and residents at the Fairview University Breast Center and Jinjin Zhang for assistance with patient studies

Thanks to S. Suddarth and A. Rath of Agilent, B. Hannah,J. Strupp, and P. Anderson of CMRR for software and hardware support.

Thanks especially to Djaudat Idiyatullin, Mike Garwood, Mike Tesch, and Ryan Chamberlain (The rest of the SWIFT team) and colleagues at the UMN CMRR!

ISMRM 2012, Wed. May 9

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NMR and Convolution

* =

h(t)

r(t)spin impulse response

x(t)RF pulse

systemresponse

NMR and ConvolutionThe fundamental basis of SWIFT signal processingis that a frequency modulated pulse alters the system response away from the familiar hard pulse impulse response.In the small flip angle limit the relationship is convolution. Practically it works well up to 90°.

ISMRM 2012, Wed. May 9

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SWIFT and Correlation

=x(t)RF pulse

Recovering a standard FID by correlationSWIFT produces an FID if the raw data (system reposnse) is correlatied with the complex RF pulse shape as a post processing step.

In practice this is performed in the frequency domain by multiplication with the complex conjugate of the complex pulse profile.

r(t)systemresponse h(t)

spin impulse response