Clinical MR Spectroscopy

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Clinical MR Spectroscopy

• Lawrence N. Tanenbaum, M.D. FACR
• New Jersey Neuroscience Institute
• Seton Hall School of Graduate Medical Education
• drt_at_drtmasters.com www.drtmasters.com
• JFK Medical Center Edison Imaging
• Edison, New Jersey

1.5 T
3.0 T
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What is MR Spectroscopy?

• EM energy impinges on a sample which then absorbs
  or emits energy that can be measured.
• Energy distribution and intensity provides
  information about the samples physical and
  chemical properties.
• Functional (chemical) MRS information complements
  structural MRI information.

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Functional MRtechniques

• Spectroscopy
• single voxel
• MRSI
• Diffusion
• DWI
• anisotropy
• Perfusion
• CBV, MTT, CBF
• Activation
• BOLD

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MRS techniquesmetabolites

• Proton (H)
• 1.5-3T scanner with routine hardware
• clinical software widely available
• Phosphorus, other nuclei
• requires specialized hardware
• RF amps, coils, receivers

New Orleans 2001
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MRS techniques

• Single voxel
• PROBE
• 2D multi-voxel
• PROBE SI
• chemical shift imaging/ MRSI
• 3D CSI
• 3D focal CSI

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PROBEsingle voxel proton MRS
X
PhD

• fully automated prescan, scan
• shimming
• water suppression
• 4 5 minute complete acquisition
• Short (PRESS, STEAM) and long TE (PRESS)

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single voxel MRS localization
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MRS acquisition modes

• STEAM
• stimulated echo acquisition mode
• short TE single voxel acquisition
• PRESS
• point resolved spectroscopy
• Twice the SNR of STEAM
• Short and long TE single voxel techniques now
  possible
• Long TE MRSI

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Proton MRS
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Lactate
Cho
NAA
Cr
Lipid
Cr
MI
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Short TE PRESS

• 1500 / 35
• probe-p, scan mode 1
• 96 nex scans
• 256 x 128
• FOV 21, fAP
• 20 mm thick
• 8 nex, 254

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NAAN-acetyl aspartate

• putative neuronal marker
• decreased concentration seen in focal and
  regional brain lesions
• infarction, ischemia, hypoxia, hemorrhage
• neoplasm, multiple sclerosis,
• abscess, herpes encephalitis
• epilepsy, DAT, NPH, TBI
• Canavans disease elevated NAA

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NAA
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Choline (Cho)

• marker of membrane synthesis
• high concentration seen in
• neoplasm
• developing brain
• low concentration seen in
• stroke
• liver disease
• dementia

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Creatine (Cr)

• supplier of phosphate to convert ADP to ATP
• gray matter concentration 20 gt WM
• high concentration
• increases with age
• head trauma
• hyperosmolar states
• low concentration
• neoplasm, stroke, hypoxia
• infant brain

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Lactate (Lac)

• end product of anaerobic glycolysis
• nonspecific accumulation in
• hypoxia, anoxia, infarction, hemorrhage
• neoplasm
• infection
• demyelinating disease
• hydrocephalus
• inborn errors of metabolism

Kuala Lumpur 2000
lactate
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Lactate
TE 35
TE 144
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Glxglutamate, glutamine

• glutamate is an excitatory neurotransmitter
• glutamine is a product of the reaction of
  glutamate with NH3
• elevated concentration
• hepatic encephalopathy
• hypoxia
• low concentration
• ? Alzheimers disease

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Ross B, Michaelis T Clinical Applications of MRS.
Magnetic Resonance Quarterly, Vol 10, No 4, 1994
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Myoinositol (mI)

• ? astrocyte marker, myelin breakdown product
• high concentration
• DAT
• developing brain
• multiple sclerosis
• HIV infection
• low concentration
• infarction, neoplasm
• hepatic encephalopathy

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DAT
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single voxel MRSclinical utility

• focal lesion characterization
• characteristic lesion signature
• Ddx tumor from abscess, infarction, etc.
• global / regional lesions
• hepatic encephalopathy
• dementia, epilepsy

Las Vegas 2000
NYC 2001
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Cerebral neoplasmMRS findings
Cho

• NAA decreased
• most lack neurons
• lactate accumulation
• high activity regions, cysts, necrosis
• lipid increased
• necrosis, metastatic adenoCA
• choline elevated
• accelerated membrane synthesis

New Orleans 2001
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Short TE
long TE
New Orleans 2002
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35 yo female seizures
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New Orleans 2000
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Taipei 2002
Vail 2004
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Cerebral neoplasmrole of MRS / MRSI

• characterization
• mass lesion DDx
• extent
• tumor infiltration vs. edema
• primary vs. metastasis
• surveillance
• post op enhancement vs. residual tumor
• recurrent tumor vs. radiation necrosis
• non-enhancing lesions

Snowmass 2004
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Vail 2003
Snowmass 2004
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Vail 2003
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H. Mahendran, M.D., Delhi
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H. Mahendran, M.D., Delhi
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Clinical MRSlesion characterization

• neoplasm
• infarction
• infection
• multiple sclerosis
• lesions in HIV patients
• tumor vs. radiation necrosis

Mardi Gras NO 2001
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post partum seizures
Vail 2003
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Palos Verdes 2000
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New Orleans 2000
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AIDS r/o infection
Stockholm 2002
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New Orleans 2002
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pre-op brain tumor
Glasgow 2001
R. Tien, M.D. Duke Univ
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Glasgow 2001
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Snowmass 2004
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30 yo male with tumor
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Indian patient with seizures
Istanbul 2000
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Jerusalem 2000
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Cerebral abscessMRS findings

• NAA, Cho, Cr decreased
• may see resonances from microorganism and
  proteolysis end-products
• lactate
• succinate (2.4 ppm), acetate (1.9)
• alanine (1.5), amino acids (0.9)

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Lac
abscess
Suc
AA
Acetate
Ala
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Nantucket 2000
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Chang L In Vivo MRS in HIV and HIV-related
Brain Diseases
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Chang L In Vivo MRS in HIV and HIV-related
Brain Diseases
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AIDS
Nantucket 2000
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New Orleans 2000
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Chang L In Vivo MRS in HIV and HIV-related
Brain Diseases
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3T MRSI
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AIDS
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Chang L In Vivo MRS in HIV and HIV-related
Brain Diseases
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Chang L, Miller B, McBride D, et. al. Proton MR
Spectroscopy of Brain Lesions in AIDS
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Multi-voxel spectroscopyMRSI

• multiple spectra in single acquisition
• matrix of spectra
• gray (color) scale metabolite display
• integrate with structural data
• overlay on structural images with variable
  opacity
• simultaneous evaluation of large areas of brain
• contralateral comparison information

Hermosa Beach 2000
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Long TE PRESS 2D CSI

• 1000 / 144 PRESS
• 256 x 128, FOV 21, fAP
• 10 mm thick, 1 nex
• fast
• 12 x 12, 144 voxels, 228
• 16 x 16, 256 voxels, 420
• 24 x 24, 576 voxels, 940
• preset or optimized water suppression

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NAA
Choline
Chronic MS plaque
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Cho
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Meningioma
NAA
Cho
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lesion characterization
brainstem glioma
NAA
Cho/NAA
Choline
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extent
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FLAIR
NAA
Cho/NAA
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FLIR T1
NAA
Cho/NAA
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Choline
NAA
Lactate - lipid
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Cho / NAA
Pelican Hill
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Multi-voxel MRSI
256 voxels 5 minutes
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Multi-voxel MRSI
256 voxels 5 minutes
Cho / NAA
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Multi-voxel MRSI
edema
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Cho/NAA
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Cho / NAA
NAA
Choline
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Multi-voxel MRSI TE 144
256 voxels 5 minutes
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3T MRSI
tumor vs. radiation necrosis
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3D CSI
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3D focal CSI

• 1000 / 144 (288) PRESS
• 50 (3-100) mm voxel thickness
• 8 (8-16) locs (slices) per slab (volume)
• 8 mm spacing (thickness)
• 8 x 8, 512 voxels (64 / slice), 832
• very selective spatial saturation
• 6 defaults at edge VOI
• 4 explicitly prescribed
• 256 x 128, FOV CSI volume, fAP, 1 nex

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glioma
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Cho
Lac Lipid
Cho / NAA
NAA
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8 channel NV coil
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3D CSI 3T
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TwinSpeed 3D focal CSI
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acetate
NAA
Lac
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Multi-voxel MRSI

• thorough lesion characterization
• lesion mapping
• nature, extent
• multiple biopsies
• edema, wall, center
• reduce sampling error
• complex lesions
• radiation necrosis / post operative change vs.
  tumor

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Multi-voxel MRSI

• regional lesions
• epilepsy
• dementia
• traumatic brain injury

Steamboat 2001
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NAA
Choline
mesial temporal sclerosis
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MTS
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L
MTS
R
L
R
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PSIR
NAA
Cho
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Traumatic brain injury
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Clinical MRScost / clinical benefits

• refine lesion characterization
• facilitate early diagnosis, treatment
• decrease invasive diagnostic and therapeutic
  procedures
• reduce need for follow-up, ancillary studies
• impact workup / Rx of global brain lesions
• facilitate diagnosis DAT, TBI
• lateralize TLE

NYC 2001
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Prostate MRSI
Citrate
Cho
Cho
CA
normal
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3D PROBE SI
Citrate
ChoCr
Cho
Cr
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Metabolic Identification Of Prostate Cancer
Cancer
Healthy
Axial T2 Weighted MRI
0.24 cc in vivo proton spectrum from a 3D array
of spectra
University of California San Francisco
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Prostate MRSIimpact

• traditional role for imaging is staging
• poor clinical acceptance
• insufficient accuracy?
• reduced surgery?
• MRSI improves specificity
• differentiate benign SI changes from malignancy
• allows identification and localization of cancer

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Prostate MRSIclinical role

• high PSA, negative biopsy
• options
• repeat biopsy blindly
• repeat biopsy blindly
• repeat biopsy blindly
• identify and localize cancer with MRSI
• perform directed biopsy for characterization

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Prostate MRSIclinical role

• positive biopsy
• guide super selective radiation therapy to
  cancerous portion of prostate gland

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Outcome studies

• HIV
• About 20 of MRI- patients have significant MRS
  changes (Marseilles, France)
• Adrenoleukodystrophy
• 25 of MRI- boys with affected sib have
  significant MRS abnormalities (Gottingen,
  Germany)
• Near drowning
• MRS defined 5/5 good and 11/12 poor outcome
  between days 2 and 4 after rescue (Pasadena,
  California)
• Temporal lobe epilepsy
• 55/60 patients successfully lateralized (London,
  UK)

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Moats, Watson, Shonk, et al. SMRM 1993.
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Case study
new onset seizures
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Case study Diagnosis Infarction
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Final exam
New Orleans 2000
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Dyslexia
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Schizophrenia
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Depression
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Mardi Gras NO 2001
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Clinical MRSI

• Lawrence N. Tanenbaum, M.D. FACR
• New Jersey Neuroscience Institute
• Seton Hall School of Graduate Medical Education
• JFK Medical Center Edison Imaging
• Edison, New Jersey