Central nervous system lymphoma characterization by diffusion-weighted imaging and MR spectroscopy

Area of Science:

• Neuroradiology
• Oncology
• Medical Imaging

Background:

• Central nervous system (CNS) lymphoma diagnosis is critical for treatment and prognosis.
• Distinguishing CNS lymphoma from other conditions requires accurate imaging.
• Diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) offer advanced insights into tissue characteristics.

Purpose of the Study:

• To characterize the diffusion-weighted imaging (DWI) and MR spectroscopic (MRS) findings in CNS lymphoma.
• To evaluate the utility of DWI and MRS in the diagnosis and management of CNS lymphoma.

Main Methods:

• Retrospective analysis of 20 patients with histopathologically confirmed CNS lymphoma.
• MR imaging included DWI (b = 1000s/mm2) and apparent diffusion coefficient (ADC) maps.
• MR spectroscopy (MRS) used PRESS sequence to assess metabolite ratios and identify lactate/lipids.

Main Results:

• Restricted diffusion observed in 90% of pretreatment CNS lymphoma scans.
• Median metabolite ratios (Cho/Cr, NAA/Cho, NAA/Cr) and presence of lactate/lipids were documented.
• Lesion locations varied, commonly in subcortical white matter and extra-axial spaces.

Conclusions:

• Restricted diffusion is a consistent finding in CNS lymphoma, particularly in immunocompetent patients.
• DWI and MRS are valuable tools for initial diagnosis and post-treatment surveillance of CNS lymphoma.
• Imaging appearances can differ between immunocompetent and immunosuppressed individuals.