Repeat It With Me: Reproducibility Team Challenge : UTE 31P 3D MRSI at 3T/7T with Rosette k-space Trajectory

ISMRM Repeat It With Me: Reproducibility Team Challenge

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Abstract: Ultra-Short Echo Time 31P 3D MRSI at 3T/7T with Novel Rosette k-space Trajectory

Conference: International Society for Magnetic Resonance in Medicine Annual Meeting 2022 At London
Abstract #ID: 1783

GitHub: GitHub - uzayemir/31P-MRSI: Ultra-Short Echo Time 31P 3D MRSI at 3T with Novel Rosette k-space Trajectory

Our group proposes a 31-P MRSI sequence utilizing Rosette-Petal shaped 3D k-space acquisition to achieve 1 mL isotropic resolution (10x10x10mm^3) over a FOV of 480x480x480mm^3 with a total scanning duration of 6.7 minutes using a Siemens Prisma 3T/7T scanner.

Method

A custom rosette trajectory (Shen et al. 2022) was used with an isotropic FOV = (480mm)^3 and an imaging matrix grid of 48x48x48 voxels. The spectral bandwidth was 2083 Hz, a TE = 50 us, a TR = 350 ms, and a total of 1444 Petals. Total scan duration = 8.4 minutes. Anatomical data was acquired through an Ultrashort Echo Time Magnetization Transfer (UTE-MT) sequence which uses a pair of adiabatic hyperbolic secant (sech) 180-degree pulses with a pulse duration of 24ms, a pulse bandwidth of 1kHz, an offset frequency of ~1300 Hz from water. Image reconstruction and post-processing steps were performed in MATLAB (MathWorks, USA). Nonuniform fast Fourier transform (NUFFT) was used to calculate the forward encoding transform of the acquired k-space data. A compressed sensing approach was used for image reconstruction, using total generalized variation (TGV) as the sparsifying penalty. The complex-valued coil sensitivity maps were first extracted from the center of k-space using ESPIRIT for coil combination. We used LCModel for the quantification of in vivo 31P NMR Brain Spectra.

In order to achieve acceptable acquisition timing in clinical settings (reconstructed images with acceleration factors = 2 and 4 were tested for further acceleration purposes.

Please contact
Uzay E Emir uemir@purdue.edu

If you are interested in reproducing our abstract.

We are looking forward to your feedback!

https://www.researchgate.net/publication/358462656_Ultra-Short_Echo_Time_31P_3D_MRSI_at_3T_with_Novel_Rosette_k-space_Trajectory

Shen, Xin, et al. “Ultra-short T2 components imaging of the whole brain using 3D dual-echo UTE MRI with rosette k-space pattern.” Magnetic Resonance in Medicine (2022).

Here is the proposed acquisition protocol… The Total acquisition duration will be 36 minutes. We will test the acquisition with an acceleration factor of up to 6 corresponding to a 31P MRSI acquisition of 4.5 minutes.

More Details have been provided.

https://github.com/uzayemir/31P-MRSI/blob/main/README.md

Pulse diagram with a delay of 10 us between RF pulse and the ADC

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Results

(α-ATP+β-ATP+γ-ATP)/phosphocreatine (PCr) and inorganic phosphate (Pi)/PCr

Lcmodel findings of accelaration factor = 1

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(α-ATP+β-ATP+γ-ATP)/phosphocreatine (PCr)

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inorganic phosphate (Pi)/PCr

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Lcmodel findings of accelaration factor = 2

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(α-ATP+β-ATP+γ-ATP)/phosphocreatine (PCr)

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inorganic phosphate (Pi)/PCr

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Lcmodel findings of accelaration factor = 4

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(α-ATP+β-ATP+γ-ATP)/phosphocreatine (PCr)

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inorganic phosphate (Pi)/PCr

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in addition to muscle and brain, we also tested the heart. More body organs to challenge.

UTE 31P 3D Rosette MRSI Reproducibility Team is on board.

uzay emir Purdue University
Ulrich Pilatus Goethe University Frankfurt
Seyma Alcicek Goethe University Frankfurt
Alexander Richard Craig-Craven UNIVERSITY OF BERGEN

Comparison of Compressed Sensing Accelerated Rosette UTE and Conventional 31P 3D MRSI at 3T in Leg Muscle

Fast 3D 31P MRSI Using Novel Rosette Petal Trajectory at 3T with x4 Accelerated Compressed Sensing