Fast 3D-P31-MRSI Using Custom Rosette Petal Trajectory at 3T with 4x Accelerated Compressed Sensing

1. Fast 3D-P31-MRSI Using Custom
Rosette Petal Trajectory at 3T with 4x
Accelerated Compressed Sensing
Uzay E Emir
School of Health Sciences, Purdue University, West
Lafayette, IN, United States
Weldon School of Biomedical Engineering, Purdue
University, West Lafayette, IN, United State

2. Speaker Name: Uzay Emir
I have no financial interests or relationships to disclose with regard to the subject
matter of this presentation.
Declaration of
Financial Interests or Relationships

3. Phosphorus‐31 (31P MRS ) the oldest MRS
methodology
• Magnetic Resonance Spectroscopy (MRS) is
able to profile the chemical composition of
defined regions of interest
• The 1H nucleus is the most commonly
probed
• Phosphorus‐31 (31P MRS ), the oldest
MRS methodology, does not suffer from
problems of water and fat
contamination and requires a less
homogeneous magnetic field.
Metabolites Chemical shift (ppm)
Phosphocreatine (PCr) 0
α-ATP, β-ATP, γ-ATP -7.56, -16.18, -2.53
Inorganic phosphate (Pi) 4.84
Phosphorylcholine (PC ) 6.23
glycerol-3-phosphorylcholine (GPC) 2.94
phosphorylethanolamine (PE) 6.77
glycerol-3-phosphorylethanolamine (GPE) 3.49
membrane phospholipids (MP) 2.3
Total nicotinamide adenine dinucleotide
(reduced form, NADH and oxidized form, NAD+) -8.13, -8.30

4. The oldest but still unattractive
The oldest and attractive
• 31P MRS is Unattractive
• A lack of technical development and
integration into clinical MRI systems
• Low SNR
• poor spatial resolution
• long acquisition time
• Lack of processing software available
for automated quantification of the
metabolites
• 31P MRS is attractive
• Increased SNR
• Increased Resolution
• Short acquisition duration
• Automated quantification of the
metabolites

5. Ultra-Short
Echo Time 31P
3D MRSI at 3T
with Novel
Rosette k-
space
Trajectory

6. Methods
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.
We used LCModel to
quantify in vivo 31P NMR
Brain Spectra using LCModel.
Procedures will be repated
for acceleration factor of 4
Siemens Prisma 3T UTE Rosette
TR 350 ms
Delay between RF pulse and ADC 10 μs
Bandwidth 2200 Hz
Phase Encoding 24 x 24 x 24
FOV 48 cm x 48 cm x 48 cm
Nominal Voxel Size 8 cm3
Averages 3
Acquisition Full Rosette
Total Scan Time 27 minutes

7. Results Total
ATP/ PCr Maps

8. Results
Acceleration Factor = 1
Total Acquisition = 27 minutes
SNR of Lcmodel = 11
Acceleration Factor = 2
Total Acquisition = 13.5 minutes
SNR of Lcmodel = 9
Acceleration Factor = 4
Total Acquisition = 6.75 minutes
SNR of Lcmodel = 7

9. Conclusion and
Discussion
Increased SNR
Increased Resolution
Short acquisition duration
Automated quantification of the
metabolites
Technical advances make 31P MRS a
viable option clinically, and it is now
appropriate to develop and evaluate
protocols suitable for clinical practice
and use them to investigate brain
metabolism.

10. Collaborators
Purdue
• Ulrike Dydak
• Brandon
Keehn
• Deva Chan
• Riyi Shi
• Joseph Rispoli
• Daniel Foti
• Jason Cannon
• Wei Zheng
• Sean Lane
• Xin Shen
• Nicholas
Farley
• Antonia
Sunjar
• Aparna Karnik
• Ahmad Al-
Hulail
Cambridge
• Zoe Kourtzi
• Guy Williams
• Stephen Sawiak
Oxford University
• Mark Chiew
EPFL
• Lijing Xin
UCSF
• Peder Larson
UCLA
• Albert Thomas
• Ajin Joy
MGH
• Matthew Rosen
• Neha Koonjoo
UNIVERSITÄTSKLINIKUM FREIBURG
• Ali Caglar Ozen
The study was supported by the Indiana CTSI and
funded in part by grant #UL1TR001108 from the
National Institutes of Health (NIH), National Center for
Advancing Translational Sciences (NCATS) Clinical
and Translational Science Awards (CTSA)
Showalter Trust Purdue MRI Facility