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1H MRS and Volumetric MRI Studies of Multiple Sclerosis ...

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    1H MRS and Volumetric MRI Studies of Multiple Sclerosis ... 1H MRS and Volumetric MRI Studies of Multiple Sclerosis ... Presentation Transcript

    • 1 H Magnetic Resonance Spectroscopy (MRS)
      • Introduction
        • commonly detectable metabolites
        • commonly used 1 H MRS data acquisition methods
        • examples of 1 H MRS applications in studies of neurodisorders and breast cancer
    • Introduction
      • useful and important as an additional evaluation tool for various neurodisorders, such as brain cancer, stroke, epilepsy, Alzheimer’s disease, multiple sclerosis, etc.
      • Neuro 1 H MRS scans reimbursable.
      • Research beyond neuro-applications
        • breast cancer
        • prostate cancer, etc.
    • Commonly detectable Brain Metabolites at low field strength (  1.5T)
      • N-acetylaspartate (NAA)
        • neuronal marker
        • 2.02 ppm
      • Total creatine (Cr: creatine and phosphocreatine)
        • Energy storage molecules in tissue
        • Stable concentration, as internal reference in MRS studies
        • 3.03 ppm
      • Choline compounds (Cho: phosphocholine, glycero- phosphocholine)
        • cell membrane turnover
        • precursor of molecules for cellular signal transduction
        • 3.23 ppm
      • Lactate (Lac)
        • anaerobic glycolysis
        • 1.33 ppm
      • Myo-inositol (mI)
        • glial marker
        • precursor of molecules for cellular signal transduction
        • 3.56 ppm
      • Higher filed strength (  3 T)
        • improved S/N, spectral resolution
        • more detectable metabolites, such as Gaba
        • separating glutamate and glutamine
        • 13 C MRS --- glucose metabolism
        • 31 P MRS --- energy metabolism
    • Common 1 H MRS data acquisition
      • PRESS (Point RESolved Spectroscopy, 90 o -180 o -180 o )
        • stronger signal, long TE application
      • STEAM (STimulated Echo Acquisition Mode, 90 o -90 o -90 o )
        • weaker signal, short TE application
      • Water suppression (H 2 O ~ 50 M, metabolites ~ 1-10 mM)
        • CHESS (chemical shift selective) pulses for saturation
      • Single voxel
      • Multi-voxel (CSI, MRSI)
        • 2D, multi-slice
        • 3D
      • PRESS sequence
      • STEAM sequence
      90 o 90 o TE/2 TM TE/2
    • Single-Voxel MRS Studies of Alzheimer’s Disease ( Neurology 2001; 57: 626-632)
    • 1 H MRSI Study in Multiple Sclerosis (TE/TR: 135/1500 ms)
    • Common 1 H MRS data quantitation
      • Metabolite ratio (ratio of peak areas): NAA/Cr, Cho/Cr
      • Absolute quantitation: mmol/tissue volume
        • Internal reference: Cr, H 2 O
        • Phantom replacement method --- correction for coil load
        • External reference --- correction for B1 inhomogeneity
        • * MRS signals are both T 1 and T 2 -weighted, corrections for differences in T 1 and T 2 between in vivo tissue and aqueous solution environments.
    • Single-Voxel MRS Studies of Alzheimer’s Disease ( Neurology 2001; 57: 626-632)
    • Single-Voxel MRS Studies of Alzheimer’s Disease
    • Single-Voxel MRS Studies of Alzheimer’s Disease
    • Single-Voxel MRS Studies of Down Syndrome ( Am J Psychiatry 1999; 156: 1879-1886 )
    • Single-Voxel MRS Studies of Ts65Dn Mouse ---Down Syndrome Model ( NeuroReport 2000; 11: 445-448 )
    • Single-Voxel MRS Studies of Ts65Dn Mouse ---Down Syndrome Model
      • mI mI-1- phosphate
      Li
    • 1 H MRSI Study in Multiple Sclerosis (TE/TR: 135/1500 ms)
      • Significant correlations between NAA/Cho, NAA/Cr, CCSF volume fraction (of the total brain and CSF volume), and BRB scores
    • Relation between overall neuropsychological performance and standardized predicted score from a multiple regression model including: central cerebral atrophy, lesion volume, and RPPV NAA/Cho (R = - 0.785 p < .001)
    • NAA quantification using CSF water as internal reference
      • Reference MRSI scan without water suppression, 1 scan average, other parameters kept the same
      • Water signal from CSF voxel as internal reference
      • NAA/H 2 O ratio corrected for CSF volume fraction in the MRS voxel.
    • 1 H MRS Study of Breast Cancer
      • High false positive rate (60-80%) in conventional mammography, resulting unnecessary biopsy.
      • Recently, dynamic contrast enhancement (DCE) T 1 -weighted MRI ---- an integral part of a standard breast cancer diagnostic protocol.
      • Excellent sensitivity (88-100%)
      • Specificity rather variable (37-97%)
    • 1 H MRS Study of Breast Cancer
      • Promising tools for improving specificity in detection of breast malignancy:
        • 1 H MRS
        • Perfusion T 2 *-weighted MRI
      • 1 H MRS measurement
        • detection of enhancing Cho signal, marker of active tumor
    • 1 H MRS Study of Breast Cancer
    • 1 H MRS Study of Breast Cancer Single-voxel MRS, PRESS (TE/TR 135/2000 ms)
    • 1 H MRS Study of Breast Cancer
      • DCE MRI :
        • 100% sensitivity, no false negative
        • 9 out of 39 positive turned out benign by biopsy
        • ------ 77% specificity.
      • DCE MRI + MRS :
        • no false negative
        • 3 out of 26 MRS cases turned out false positive ------ 88% specificity
    • 1 H MRS Study of Brain Cancer
      • In recent years, in addition to conventional pre- and post-contrast MRI, several other MR techniques have been used for the diagnosis and evaluation of brain tumors.
      • 1 H MRS: diagnosis, clinical evaluation of tumor response to therapy, differentiate tumor recurrence and radiation necrosis.
        • Elevated Cho signal is a marker of viable tumor
      • Diffusion Weighted Imaging (DWI):
      • differentiate necrosis, edema, and viable tumor regions.
      • Perfusion Imaging:
      • evaluate tumor vascularity, assess tumor grade.
    • Monitoring tumor response to intracarotid therapy using MRS
    • Post-contrast T1 Images and Proton Spectra of a Patient with CNS Lymphoma
      • Pre - ICC Post - 1st ICC Post - 4th ICC
    • ADC and rCBV Maps of a Patient with CNS Lymphoma
      • Pre - ICC Post - 1st ICC Post - 4th ICC
    •  
    • Localization of Spectroscopic Voxel for a Patient with Metastatic Squamous Cell Carcinoma
      • Pre-therapy Post-therapy
      1 H MRS for Monitoring Head and Neck Cancer Response to Therapy
    • Proton Spectra of a Patient with Metastatic Squamous Cell Carcinoma
      • Pre-therapy Post-therapy
    • Localization of Spectroscopic Voxel for a Patient with Squamous Cell Carcinoma
      • Pre-therapy Post-therapy
    • Proton Spectra of a Patient with Squamous Cell Carcinoma
      • Pre-therapy Post-therapy
    • Changes of Cho/Water Ratio for Head and Neck Tumor Patients
    • Discriminating Neoplastic and Non-neoplastic Thyroid Lesions Using 1 H MRS
      • 29 patients with thyroid lesion
      • 1 H MRS examination
        • PRESS single-voxel (TE/TR 135/2000)
        • at lesion (n = 29) and at normal contralateral side (n=5)
        • from healthy control (n=2)
      • Resection of thyroid mass within one week
    • Proton spectra from neoplastic thyroid lesion and normal-appearing contralateral region
      • Non-neoplastic thyroid lesion Normal healthy control
      Cho Lip/Lac
    • Significant difference in Cho/Water ratio between neoplastic (3.36  2.55, n=22) and non-neoplastic (0.16  0.11, n=7) thyroid lesions
    • Results
      • Thyroid neoplasm
      • Cho/water > 1.0 x 10 -3
      • Thyroid non-neoplasm
      • Cho/water < 0.4 x 10 -3
    • Conclusion
      • Strong correlation between MRS and pathology results
      • It’s difficult to distinguish neoplastic from non-neoplastic thyroid lesions based on conventional post-contrast T 1 -weighted images, as both are usually enhanced.
      • 1 H MRS can be a valuable screening tool with high sensitivity in detection of thyroid neoplasm.
      • Aid in treatment planning and evaluation of post-operation recurrence and node/metastasis.
    • Proton MRS Studies of Pediatric Neurodisorder
    • 1 H MRS Study of a child with NKH (Non Ketotic Hyperglycinemia) ( J Neuroimaging 2001; 11: 209-212 )
    • WM proton spectra at 10 and 13 months (TE/TR 270/2000)
    • Correlation of plasma and brain glycine levels
    • 1 H MRS Study of a child with ADEM (Acute Disseminated Encephalomyelitis)
      • Brain Metabolite Ratios in a Child with ADEM
      • MRS Study NAA/Cr Cho/Cr Lac/Cr
      • Voxel
      • BG initial 0.71 0.76 0.51
      • BG follow-up 0.83 0.88 0.21
      • WM initial 1.62 0.91 0.00
      • WM follow-up 1.38 1.10 0.00
    • In vivo 1 H MRS study of a rat model of autism ( Physiol Behav 2002; 75: 403-410)
    • PRESS (TE/TR 40/2000), 0.2 cc voxel size
    • Significant decrease of NAA/Cr in autistic rats
    • Significant increase of Cho/Cr in autistic rats
    • Significant increase of mI/Cr in autistic rats
    • 1 H MRS study of autistic human subjects (PRESS, TE/TR 40/2000)
    • 1 H MRS study of autistic human subjects (PRESS, TE/TR 40/2000)
    • 1 H MRS study of autistic human subjects (PRESS, TE/TR 40/2000)
    • 1 H Spectra from Healthy Controls
      • Left Hipp-Amyg Cerebellum
    • 1 H MRS study of autistic human subjects
      • Metabolite Ratios in Children with PDD (N = 10) and Healthy Controls (N = 6)
      • LHA RHA Cerebellum
      • PDD Control PDD Control PDD Control
      • NAA/Cr 1.97  0.32* 2.42  0.32 1.94  0.51* 2.88  0.65 1.45  0.23 1.38  0.12
      • Cho/Cr 0.72  0.21* 0.47  0.17 0.68  0.22 0.54  0.28 0.75  0.24* 0.46  0.11
      • mI/Cr 0.78  0.26* 0.50  0.17 0.72  0.31* 0.39  0.13 0.51  0.17* 0.20  0.12
      • mean  SD; *: mean in PDD group differs significantly from the control group (unpaired t-test, p < 0.05).