Alkaline pH in intracranial tuberculomas: A ³¹Phosphorus magnetic resonance spectroscopy study

Intracranial tuberculomas are one of the common causes of space-occupying lesions of the brain in developing countries. Proton (¹H) magnetic resonance spectroscopy (MRS) has shown lipid peak in intracranial tuberculomas as a characteristic feature. Phosphorus (³¹P) MRS has been used to evaluate intracranial lesions and to calculate tissue pH non-invasively. The aim of this study is to evaluate intracranial tuberculomas using ³¹PMRS.

Intracranial tuberculomas proven by stereotactic or surgical biopsy were included in the study. After routine T1- and T2-weighted sequences, ³¹P MRS was performed using single-voxel intravoxel in vivo spectroscopy (ISIS) technique in the central core of the tuberculoma (voxel size 1-2 mm³). The pH was estimated using Petroff 's method using the chemical shift between phosphocreatine and Pi.

³¹P MRS was available for 26 patients, in which there was significant positive correlation between high-energy phosphate metabolites, (markers of bioenergetic status), and low-energy phosphate metabolites (membrane phospholipids and inorganic phosphate). The calculated pH was slightly alkaline and varied from 6.97 to 7.22.

Intracranial tuberculomas showed alkaline pH in ³¹P MRS and this may be useful in the characterization of these lesions and possibly also in their treatment.