Application of³¹P MR Spectroscopy to the Brain Tumors

Abstract

ObjectiveTo evaluate the clinical feasibility and obtain useful parameters of 31P magnetic resonance spectroscopy (MRS) study for making the differential diagnosis of brain tumors.Materials and MethodsTwenty-eight patients with brain tumorous lesions (22 cases of brain tumor and 6 cases of abscess) and 11 normal volunteers were included. The patients were classified into the astrocytoma group, lymphoma group, metastasis group and the abscess group. We obtained the intracellular pH and the metabolite ratios of phosphomonoesters/phosophodiesters (PME/PDE), PME/inorganic phosphate (Pi), PDE/Pi, PME/adenosine triphosphate (ATP), PDE/ATP, PME/phosphocreatine (PCr), PDE/PCr, PCr/ATP, PCr/Pi, and ATP/Pi, and evaluated the statistical significances.ResultsThe brain tumors had a tendency of alkalization (pH = 7.28 ± 0.27, p = 0.090), especially the pH of the lymphoma was significantly increased (pH = 7.45 ± 0.32, p = 0.013). The brain tumor group showed increased PME/PDE ratio compared with that in the normal control group (p = 0.012). The ratios of PME/PDE, PDE/Pi, PME/PCr and PDE/PCr showed statistically significant differences between each brain lesion groups (p < 0.05). The astrocytoma showed an increased PME/PDE and PME/PCr ratio. The ratios of PDE/Pi, PME/PCr, and PDE/PCr in lymphoma group were lower than those in the control group and astrocytoma group. The metastasis group showed an increased PME/PDE ratio, compared with that in the normal control group.ConclusionWe have obtained the clinically applicable 31P MRS, and the pH, PME/PDE, PDE/Pi, PME/PCr, and PDE/PCr ratios are helpful for differentiating among the different types of brain tumors.

Energy Status And Metabolism in Intracranial Space Occupying Lesions: A Prospective 31p Spectroscopic Study

“…However, we did not find statistically significant difference in PME/PDE ratio in any of the group. Previous studies have found significantly high PME/PDE ratio in astrocytoma, metastases and lymphoma compared to controls [13]. But these findings are variable and have limitations as previous studies had also shown increase in both PME and PDE in most tumours , proliferating tissues like regenerating liver, benign tumours and embryo [5].…”

“…The phosphate metabolites imaged are probably intracellular as the extra cellular concentration of these metabolites is negligible [12]. The integral values obtained of each metabolites are not absolute but relative [4] and thus various metabolite ratios are used like PME/ PDE, PDE/ATP, PCr/ATP etc in various studies [5,13].…”

Proton MR spectroscopic imaging of human glioblastomas at 1.5 Tesla

“…Their examination would require extraction of the membrane and the application of organic solvents, which would allow to distinguish at least the major human brain phospholipids including phosphatidylcholine, phosphatidylserine, sphingomyelin, phosphatidylinositol, and phosphatidylethanolamine (Garett and Grisham 2008;Kornienko and Pronin 2009). However, it is possible to spectroscopically measure precursors of their synthesis and products of their degradation as the tCho signal contributors (Solivera and Law 2009;Ha et al 2013). Since the level of tCho particularly reflects the concentration of phosphocholine which is more than twice increased in highgrade gliomas (Lupo et al 2007;McKnight and Wladman 2010), tCho is suitable for monitoring tumor carcinogenesis (Guillevin et al 2008;Housni and Boujraf 2013).…”

“…Membrane phospholipids are beneficial for spectroscopic tumor detection. They perform important function as intracellular second messengers involved in the regulation of cell differentiation and proliferation (Wijnen 2010;Ha et al 2013). Unfortunately, using the in vivo 1 H MRS it is not possible to directly evaluate these phospholipids due to their incorporation in the cell membranes (Soares and Law 2009;Barker 2010).…”

“…To the tCho signal mainly phosphocholine contributes, and in a lesser extent glycerophosphocholine, free choline, and acetylcholine (Horska and Barker 2010;McKnight and Wladman 2010). Since the phosphocholine is the precursor of membrane phospholipids synthesis (Solivera et al 2009;Ha et al 2013), tCho is considered to be the most useful MRS parameter reflecting higher cellular proliferation and tumor carcinogenesis (Guillevin et al 2008;Housni and Boujraf 2013). The concentration of free creatine and phosphocreatine, detected as a joint peak tCr, has the most stable value among 1 H MRS detectable metabolites and thus it is usually used as a reference for relative metabolite quantification (Soares and Law 2009;Barker 2010).…”