Proton MR Spectroscopy - ppm of Minor Metabolites

Metabolite                PPM

Valine
Leucine                         --->      0.9 ppm
Isoleucine

Alanine                          --->     1.48 ppm

Acetate                          --->     1.9 ppm

Succinate                      ---->     2.4 ppm

Lipid / Lactate              ---->     0.8 to 1.3 ppm


PS: To differentiate Lipids vs Lactate which occur at the 1.3ppm in the short TE acquisition, and additional TE = 135ms imaging is done in which the lipids do not invert.

       Pic F - Short TE                                           Pic G - Intermediate TE

Distinguishing the Amino acid peaks of Valine, Leucine and Isoleucine at the 0.9ppm and the lactate/lipid at 0.8-1.3ppm is important in distinguishing between Cystic Tumors (Both primary and mets) from Brain Abscesses - by doing the Intermediate TE (135ms) Spectroscopy, which causes the inversion of Aminoacids and lactate peak, but not of lipid.

Image showing the inversion of lipid in intermediate TE..

MRS Metabolites

Ref: and for details refer : http://spinwarp.ucsd.edu/neuroweb/Text/mrs-TXT.htm

Revised McDonald's Criteria for MRI in MS 2010

http://onlinelibrary.wiley.com/doi/10.1002/ana.22366/pdf

Revised McDonald Criteria - Is it approved in Asian Population?

International panel revises 'McDonald Criteria' for diagnosing multiple sclerosis


http://www.eurekalert.org/pub_releases/2011-03/nmss-ipr030911.php


In past versions of the McDonald Criteria, guidelines were presented for using MRI to demonstrate dissemination of disease in time and space, based on earlier studies. For the 2010 Revised Criteria, published recommendations from the European MAGNIMS multicenter collaboration have been incorporated (Swanton JK, Rovira A, Tintoré M, et al. Lancet Neurol 2007;6:677-686; Swanton JK Fernando K, Dalton CM, et al. J Neurol Neurosurg Psychiatry 2006;77:830-833.) 


These indicate that:


Dissemination in time can be demonstrated by a new T2 or gadolinium-enhancing lesion on a follow-up MRI, with reference to a baseline scan, regardless of when the baseline MRI was obtained. (Previous versions had specified that the reference scan be performed at least 30 days after the initial clinical event; this is no longer a requirement.)
Dissemination in space can be demonstrated with at least one T2 lesion in at least two our of four areas of the central nervous system: periventricular, juxtacortical, infratentorial, or spinal cord. These lesions need not be gadolinium enhanced.
In the case of diagnosing primary-progressive MS, aspects of the previous criteria remain, but the MAGNIMS recommendations for demonstrating dissemination in space were incorporated to harmonize with other 2010 updates. 


Diagnosing primary-progressive MS requires one year of disease progression (determined retrospectively or prospectively), plus at least 2 out of these 3 criteria: dissemination in space in the brain based on at least 1 T2 lesion in periventricular, juxtacortical or infratentorial regions; dissemination in space in the spinal cord based on at least 2 T2 lesions; or positive cerebrospinal fluid (CSF) findings.


While the International Panel has provided revised and simplified criteria for MS diagnosis, recommendations for further testing of the Criteria are made as well, to bolster the scientific evidence supporting the 2010 recommendations.


Comment: The 2010 Revisions to the McDonald Diagnostic Criteria for MS should speed and make easier and more certain the diagnosis of MS. As with the original Criteria, these need prospective study, and it is expected that additional research will result in further refinements.

NOTE : "The McDonald Criteria have not yet been validated in Asian and Latin American populations, and studies need to be done to confirm the sensitivity and specificity of the Criteria in such patients."