Role of Diffusion Weighted Imaging and MR Spectroscopy in Characterisation of Intracranial Neoplasms

Abstract

Introduction: MR Imaging plays an important role in the evaluation of intracranial tumours. Conventional MRI, despite its excellent soft tissue characterization, fails to provide details about grading and infiltration of tumours. Advanced MR sequences like diffusion weighted (DW) and MR spectroscopy (MRS) can differentiate between low grade and high grade tumours and thus help the clinician in management of brain tumours. Objective: To localize and characterise various intracranial masses on conventional MR sequences, to assess the usefulness of DW and MRS in characterising the mass lesions and to correlate the inferences with histopathology or clinical follow up. Materials and Methods: Total of 67 patients over a period of one year, presenting to the department of Radiodiagnosis and Imaging, Dayanand Medical College and Hospital, Ludhiana, were included in this study. Conventional MR sequences along with DW and MRS were done after taking localisers in all the three planes. Results: Most common cerebral neoplasms were metastases followed by Glioblastoma Multiforme (GBM). Male: female ratio was 1.5:1. Headache was the most common presenting complaint. Apparent Diffusion Coefficient (ADC) values were similar in GBM and metastases but were higher in low grade gliomas. On MRS, choline levels in the areas of diffusion restriction were higher and NAA levels were lower in cases of GBM, metastases and lymphoma as compared to low grade gliomas. Conclusion: DW imaging with ADC values and MRS in combination with conventional MRI are very useful in detection of brain tumours and distinguishing low grade from high grade tumours.

Keywords

• apparent diffusion coefficient
• choline
• gliomas
• metastases
• n- acetyl aspartate