Poster Presentation Australian & New Zealand Society of Magnetic Resonance Conference 2017

Test-retest repeatability of neuro metabolites with two-dimensional localised correlation spectroscopy (2D L-COSY) at 3T in the human brain (#93)

Jameen ARM 1 , Oun Al-iedani 1 , Karen Ribbons 2 , Scott Quadrelli 3 , Rod Lea 4 , Jeannette Lechner-Scott 2 3 4 , Saadallah Ramadan 1 4
  1. School of Health Sciences, University of Newcastle, Newcastle, NSW, Australia
  2. Neurology, John Hunter Hospital, New Lambton Heights, NSW, Australia
  3. School of Medicine and Public Health, University of Newcastle, New Lambton Heights, NSW, Australia
  4. Hunter Medical Research Institute, New Lambton Heights, NSW, Australia

Background

2D L-COSY has been successfully applied in vivo to investigate metabolic profiles in brain1-5, muscle6, and breast7. To improve peak separation, most 2D L-COSY have been performed at 3T, however, there has been no test-retest repeatability study conducted at 3T to assess the precision of in vivo metabolic concentrations. The primary objective of this study was to evaluate the test-retest reliability of 2D L-COSY in detecting brain metabolites in a phantom and healthy controls (HC) in a 3T system.

 

Method

Ethics approval was sought prior to study. In-vitro evaluations were performed on brain phantom containing brain metabolites at physiological concentrations and pH. After informed consent, six HC had eight-weekly scans over a period of three months.  To evaluate any inter-week effects on MRS, there was a one month interval between the first set and second set of four-weekly scans. 2D L-COSY was acquired from the posterior cingulate gyrus from a 27cm3 voxel. Raw spectral data was processed with Felix software1. Intra and inter-subject variability were measured. Test-retest repeatability was calculated using coefficient of variation (CV), standard error measurement (SEM) and intra-class correlation coefficient (ICC), using SPSS software.

 

Results

Twenty-two metabolites were studied. CV for in-vitro and in-vivo data ranged from 0.71% to 17.86% and 2.98% to 36.86%, respectively.  N-acetyl aspartate, choline, creatine, lysine and phenylalanine were found to be consistently reliable in intra/inter subject measurements.  The SEM for in vivo data ranged from 0.0016 to 0.08.  The ICC was more than 0.95 for diagonal peaks while the ICC for cross peak were not less than 0.45, which reflects minimum variability between repeated measurements. The inter-week interval had minimal effect on metabolite ratios (p=0.08).

Conclusion

The low variability in metabolite concentration in this study shows a high level of reliability of 2D L-COSY in the human brain.

References

  1. Ramadan S, Andronesi OC, Stanwell P, et al. Use of in vivo two-dimensional MR spectroscopy to compare the biochemistry of the human brain to that of glioblastoma. Radiology 2011;259(2):540-549.
  2. Nagarajan R, Sarma MK, Thames AD, et al. 2D MR Spectroscopy Combined with Prior-Knowledge Fitting Is Sensitive to HCV-Associated Cerebral Metabolic Abnormalities. Int J Hepatol 2012;2012:179365.
  3. Nagarajan R, Sarma MK, Thomas MA, et al. Neuropsychological function and cerebral metabolites in HIV-infected youth. J Neuroimmune Pharmacol 2012;7(4):981-990.
  4. Lin AP, Ramadan S, Stern RA, et al. Changes in the neurochemistry of athletes with repetitive brain trauma: preliminary results using localized correlated spectroscopy. Alzheimers Res Ther 2015;7.
  5. Verma G, Mohan S, Nasrallah MP, et al. Non-invasive detection of 2-hydroxyglutarate in IDH-mutated gliomas using two-dimensional localized correlation spectroscopy (2D L-COSY) at 7 Tesla. J Transl Med 2016;14(1):274.
  6. Ramadan S, Ratai EM, Wald LL, et al. In vivo 1D and 2D correlation MR spectroscopy of the soleus muscle at 7T. J Magn Reson 2010;204(1):91-98.
  7. Ramadan S, Arm J, Silcock J, et al. Lipid and Metabolite Deregulation in the Breast Tissue of Women Carrying BRCA1 and BRCA2 Genetic Mutations. Radiology 2015;275(3):675-682.