Continuing its focus in the field of Oncology, QUIBIM is proud to offer an advanced MR Spectroscopy analysis tool. This tool developed in house by QUIBIM will help oncologists to improve diagnosis and treatment of brain gliomas, a disease that has an incidence of 22.6 per 100.000 population in United States.
In order to have reproducible, reliable and accurate information from tumors, we provide physicians with quantification of the metabolite by analyzing Magnetic Resonance Spectroscopy (MRS) images. MRS is a non-invasive imaging technique widely used to obtain chemical information by detecting relevant metabolites concentration from a spectrum.
Even though it is possible to detect almost any metabolite in the body, QUIBIM is currently focusing on the detection of the 2-Hydroxyglurate (2HG) because of its influence in the prediction of low-grade brain gliomas. 2HG is a metabolite, normally present at very low levels in healthy cells and tissues because of the reduction of α-ketoglutarate (α-KG) catalyzed by isocitrate dehydrogenase (IDH) protein. The IDH enzyme mutation in low-grade brain gliomas produces an accumulation of 2-HG which makes the measurement of this oncometabolite crucial to distinguish IDH-mutant gliomas from other brain mass (Stefan, et al., 2010).
MRI quality assurance
The quality assurance of the Magnetic Resonance Imaging (MRI) images is important and mandatory to ensure consequent and reliable results from the MR analysis. For that reason, a qualitative evaluation of the images is performed by QUIBIM to guarantee a strict and standard control of the images by checking the accomplishment of the MRI acquisition protocol set and the absence of artifacts.
MRS quality assurance
The first technical information QUIBIM provides with, is the graphical representation of the voxel placement in the sagittal, axial and coronal view depicted in a structural image. This quality review is important in order to assure the correct position of the voxel in the MRS acquisition avoiding necrotic tissue or non-tumor substances what can affect MRS results.
Once the quality check of the MRS acquisition is done, QUIBIM produces a technical structured report, quantitative and graphical information about the MRS analysis.
The report, apart from the main images and quantitative information, includes a spectrum graph and the voxel placement. Each peak of the spectrum corresponds to a different substance or metabolite with a different resonance frequency. This difference is usually measured in an independent scale besides the principal magnetic field (parts per million). The intensity of each peak is related to the concentration of the substances in the studied volume (Sánchez, et al., 2001).
To perform the analysis, the voxel in the tumor area and a reference acquisition corresponding to water are required. An automatic analysis of the spectrum is done providing this information and setting the up and down boundary value in ppm according to the metabolite searched. Then, we automatically process the spectrum filtering the water peak in the time domain, reducing the spectrum noise, adjusting the ppm scale according to Creatine and Choline position, and correcting the phase of the signal in order to also correct the baseline offset level to ensure the reliability and accuracy of metabolites’ concentration (Martí-Bonmatí & Alberich-Bayarri, 2013).
Therefore, it is possible to obtain from the studied metabolite its absolute concentration, the percentage of standard deviation (%SD) and its relative concentration using Creatine as a reference value (/Cr), sometimes adding other reference metabolites like PCr as the example of Figure 1 (/Cr+PCr).
The information provided by the standard deviation is essential to read MRS results because absolute concentration reliability depends on them: metabolites with a %SD less than 50 are practically undetectable with this data whereas a %SD<20 is a rough criterion for estimates of acceptable reliability. In addition, the third column indicates ratio relative to /Cr. This quantitative information will appear in the lower part of the report followed by a space for the signature of the scientist from QUIBIM once the analysis is done.
MRS analysis is now available in QUIBIM Precision® Platform to support oncologists and radiologists in brain gliomas treatment and diagnosis.
- Francesca Branzoli, *. A. (2018). Highly specific determination of IDH status using edited in vivo magnetic resonance spectroscopy. Neuro-Oncology, 907-916.
- Martí-Bonmatí, L., & Alberich-Bayarri, Á. (2013). Disease Biomarkers: Modelling MR Spectroscopy and Clinical Applications in Bioinformatics of Human Proteomics. Valencia: Springer.
- Min Zhou, *. Y. (2018). Diagnostic accuracy of 2-hydroxyglutarate magnetic resonance spectroscopy in newly diagnosed brain mass and suspected recurrent gliomas. Neuro-Oncology, 1262-1271.
- Sánchez, J., Santos, A., SantaMarta, C., Benito, C., Benito, M., & Desco, M. (2001). Herramienta de Análisis de Espectros de RM. CASEIB. Madrid.
- Stefan, G., Rob A., C., Mark D., M., Edward M., D., Mark A., B., Hyun Gyung, J., . . . David P., S. (2010). Cancer-associated metabolite 2-hydroxyglutarate accumulates in acute myelogenous leukemia with isocitrate dehydrogenase 1 and 2 mutations. Journal of experimental Medicine, 207(2), 339–344.