mr spectroscopy at 7t - university of pennsylvania spectroscopy at 7t university of pennsylvania...
TRANSCRIPT
![Page 1: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/1.jpg)
MR Spectroscopy at 7TMR Spectroscopy at 7T
University of PennsylvaniaDepartment of Radiology
University of PennsylvaniaDepartment of Radiology
Harish Poptani, Ph.D.Harish Poptani, Ph.D.
RA DI O LO G Y
HUP
![Page 2: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/2.jpg)
GLxmI
mI
NAA
Lac
CrCho
Cr
GLxNAA
Asp
CrCho
mI
Cr
mIGLx Asp
NAA
LacGLx
NAA
Glx
ASP
Increased chemical shift dispersion
3 Tesla
7 TeslaSteam
Steam
NYU, Siemens
![Page 3: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/3.jpg)
Milk phantom
SVS steam, TE = 30 ms 8 cc voxel, 16 ave TA = 24 sec
NYU, Siemens
![Page 4: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/4.jpg)
Single voxel, one acquisition!
Minnesota, Varian
![Page 5: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/5.jpg)
Tkac et al, Minnesota, Varian 7T
Increased SNR at 7T
![Page 6: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/6.jpg)
Scheenen TWJ et al. Magn Reson Mat Phy Biol Med 21:95-101, 2008
3D MRSI, TE 30, 0.14 cc voxel, 10mins, LASER ,Adiabatic pulses, SiemensSurface coil
MRSI of much smaller voxels!
![Page 7: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/7.jpg)
3D MRSI, TE 50, 0.14 cc voxel, 10mins LASER seq, CP head coil
High resolution metabolite maps
NAA Cho Cr
Scheenen TWJ et al. Magn Reson Mat Phy Biol Med 21:95-101, 2008
![Page 8: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/8.jpg)
fMRS at 7T
Minnesota, Varian
![Page 9: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/9.jpg)
fMRS
Minnesota, Varian
![Page 10: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/10.jpg)
Unedited schemes cannot be used for robust detection of Glutathione which is at the shoulder of Creatine.
Creatine
Glutathione
Radhika Srinivasan, UCSF, GE
Detecting GSH
![Page 11: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/11.jpg)
Chemical Shift (ppm)3.5 3.0 2.5 2.0
Cycle 1
Cycle 2
Differencespectra
GSH
3T edited GSH (phantom)
The Aspartyl resonance of NAA (Asp-NAA) co-edits with Glutathione in the difference spectrum
Glutathione using a spectral editing sequence
A) Spectrum without editing pulse
(B) Spectrum with editing pulse
(B-A) Difference spectrum showing GSH at 2.95 ppm.
GSH at 3T
Radhika Srinivasan, UCSF, GE
![Page 12: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/12.jpg)
3.03.5 3.0 2.53.52.5 3.0 2.5 2.03.5PPM PPM PPM
Asp-NAA
Asp-NAA
GSH NOT detected at 3T. The onlyvisible peak corresponds to Asp-NAA
PPM PPM PPM
12.0 12.2 13.2
10.9 12.0 13.3
9.4 10.3 10.9
3.03.5 3.0 2.53.52.5 3.0 2.5 2.03.5
Asp-NAA
GSH
GSH GSH
3T 7T
GSH is detected at 7T (red arrows) withthe SNR indicated in each voxel.
In-vivo detection of GSH at 3T vs 7T
Glutathione was detected at 7T with the same SNR as Glutamate studies at 3T. This level of detection from a metabolite that is present at half the concentration of Glutamate demonstrates the sensitivity of 7T MRSI.
Radhika Srinivasan, UCSF, GE
![Page 13: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/13.jpg)
Glutamate by TE averaged PRESS
Simulation study, Ralph Hurd
1.5T
3.0T
4.0T
7.0T
234
ppm
234ppm
Black: Glutamate Red: Glutamine
TE Averaged PRESSConventional PRESS
![Page 14: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/14.jpg)
JMRI 22 (2005) 279-85
1.5T
7T
Ravinder Regatte, NYU, Seimens
Corn Oil-1.5T vs 7T
![Page 15: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/15.jpg)
JMRI 22 (2005) 279-85
1.5T
Bone marrow
7T
Ravinder Regatte, NYU, Seimens
![Page 16: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/16.jpg)
Skeletal Muscle
1.5T
3.0T
7.0T
Ravinder Regatte, NYU, Seimens
![Page 17: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/17.jpg)
Qiao, H et al, MRI 49:1281-1286, 2006
Surface coil,Varian
4T
7T
31P MRS of the brain
![Page 18: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/18.jpg)
Lei, H et al, MRM 49:199-205, 2003
31P MRS of the brainNOE enhancedPrimary visual cortex7.5 ml, 8 minMinnesota, Varian
![Page 19: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/19.jpg)
Lei, H et al, MRM 49:199-205, 2003
![Page 20: MR Spectroscopy at 7T - University of Pennsylvania Spectroscopy at 7T University of Pennsylvania Department of Radiology University of Pennsylvania Department of Radiology Harish Poptani,](https://reader031.vdocument.in/reader031/viewer/2022022008/5ae1086c7f8b9ad47c8b4e11/html5/thumbnails/20.jpg)
Disadvantages• Static field distortions
– Shimming requirements –strong 2nd order shims• Chemical shift displacement errors
– Increased BW required – higher requirement for achievable peak B1 – adiabatic pulses
• Less homogenous B1– B1 shimming methods, adiabatic pulses
• Short T2 – need for shorter TE’s• SAR