ROLE OF MAGNETIC RESONANCE SPECTROSCOPY IN CHARACTERIZATION OF SUPRATENTORIAL BRAIN LESIONS

Abstract

Background: Supratentorial brain tumors present complex diagnostic challenges, often necessitating differentiation between neoplastic and non-neoplastic lesions. While magnetic resonance imaging (MRI) offers detailed anatomical insights, it sometimes lacks the specificity required for tumor characterization. Magnetic resonance spectroscopy (MRS) has emerged as a promising non-invasive adjunct, enabling metabolic evaluation of intracranial lesions. Understanding metabolite alterations through MRS may improve early tumor detection, aid in precise grading, and enhance therapeutic decision-making, potentially minimizing the need for invasive procedures.

Objective: This study aimed to assess the diagnostic efficacy of magnetic resonance spectroscopy (MRS) in evaluating patients with suspected intracranial lesions, highlighting its role in improving early detection, tumor grading, treatment planning, and overall patient outcomes.

Methods: A prospective observational study was conducted at Armed Forces Institute of Radiology and Imaging (AFIRI), Rawalpindi, from August 2024 to April 2025. Thirty patients fulfilling inclusion criteria were enrolled. Magnetic resonance spectroscopy was performed using a 1.5 Tesla MRI scanner with multi-voxel acquisition in spin-echo sequence mode. Metabolites assessed included choline (Cho) at 3.2 ppm, creatine (Cr) at 3.0 ppm, N-acetylaspartate (NAA) at 2.0 ppm, lactate at 1.33 ppm, lipid within 0.7–1.3 ppm, and myoinositol at 3.56 ppm. Cho/NAA and Cho/Cr ratios were calculated for both intralesional and perilesional regions. Statistical analysis was performed using SPSS version 25.0, considering a p-value <0.05 as significant.

Results: Among 30 patients, 19 (63.33%) were male and 11 (36.67%) were female. Age distribution revealed 8 patients (26.67%) aged 20–29 years, 6 (20.00%) aged 30–39 years, 5 (16.67%) each in 40–49 and 50–59 years, and 6 (20.00%) above 60 years. Intralesional Cho/Cr ratios ranged between 0.50–5.00 for primary tumors and 0.80–3.00 for metastases, whereas Cho/NAA ratios ranged from 0.60–7.50 for primary tumors and 2.00–10.00 for metastases. Perilesional Cho/Cr ratios varied from 0.50–7.00 in primary tumors and 0.80–2.00 in metastases, while perilesional Cho/NAA ratios ranged from 0.80–8.00 in primary tumors and 0.62–2.00 in metastases. Statistically significant differences (p<0.05) were observed in both Cho/NAA and Cho/Cr ratios when differentiating between tumor grades and tumor types.

Conclusion: The study validates the diagnostic utility of magnetic resonance spectroscopy as a non-invasive tool for evaluating supratentorial brain lesions. Intralesional Cho/Cr ratios effectively differentiated tumor grades, while perilesional Cho/NAA ratios distinguished primary tumors from metastases. The significant alterations in metabolite profiles underscore the potential of MRS in enhancing tumor characterization, aiding early diagnosis, and optimizing treatment planning.