RESUMO
Objective: To describe the spectrum of Magnetic Resonance spectroscopy in focal brain lesions and determine its diagnostic accuracy in comparison to conventional MRI using histopathology as gold standard in differentiating various types of focal brain space occupying lesions. New line.
Patients and methods: 52 patients [21 males and 31 females] with single focal brain space occupying lesion diagnosed by post contrast CT or MRI are included in this study. Complete clinical evaluation, MRI, and MRS examination were performed for all these patients before surgical biopsy and/or resection. Correlation of all these findings was done with histopathology obtained in all these patients
Results: The most important markers in differentiating and grading various types of single focal brain space occupying lesion were choline level and choline/N-acetyl aspartate ratio. There is statistically significant difference between mean of Cho/NAA in high grade glioma as it was 23.13 and low grade glioma where mean of choline/NAA was 6.21 [P value = 0.02]. Lipid and lactate peaks were more frequent in high grade tumors and lipid peak together with Choline/N-acetyl aspartate ratio could differentiate between metastasis and metastasis with delayed radiation necrosis. Alanine peak appear to be pathognomonic for meningioma. Perilesional MRS metabolites could detect actual histopathological [subclinical] extension and so differentiate between high grade and low grade tumors and between high grade tumors and metastasis
Conclusion: MRI+MRS is more sensitive than MRI alone in diagnosis, differential diagnosis, and grading of focal brain space occupying lesion. MR spectroscopy could differentiate various types of focal brain space occupying lesion with sensitivity of 92.3% while sensitivity of MRI alone was 76.9%