MRI Characteristics of CNS Large B-cell Lymphoma: Susceptibility and T2*-weighted Imaging Analysis

Overview

This large single-center retrospective study analyzed susceptibility effects (SE) on T2*-weighted and susceptibility-weighted MRI in primary and secondary CNS diffuse large B-cell lymphoma (DLBCL). The study found that SE are present in a significant proportion of cases, challenging earlier assumptions of their rarity, and identified distinct MRI patterns correlating with lymphoma subtypes and immune status.

Background

Primary CNS lymphomas, predominantly diffuse large B-cell lymphoma (DLBCL), represent the second most common primary malignant CNS tumors after gliomas. Accurate neuroradiological characterization is essential to guide diagnosis and avoid corticosteroid use before biopsy. Susceptibility effects on MRI, reflecting hemorrhage, iron deposition, or calcifications, have shown variable prevalence in CNS lymphomas, with implications for differentiating lymphoma subtypes and immune-related variants. Secondary CNS lymphoma (SCNSL) arising from systemic DLBCL is less well characterized neuroradiologically.

Data Highlights

The study included histologically confirmed DLBCL cases with cranial involvement from 2011 to 2023, using 1.5T and 3T MRI scanners with standardized T2*WI and SWI protocols. Susceptibility effects were categorized into five patterns: punctate, linear, confluent, conglomerate, and ring-like. Morphological MRI patterns were also classified based on T2WI and contrast-enhanced T1WI features, including solid, necrotic, diffuse parenchymal, perivascular, cortical/pial, and ependymal involvement. Two neuroradiologists independently reviewed images with consensus resolution.

Key Findings

• Susceptibility effects on T2*WI and SWI were observed in up to 50% of CNS DLBCL cases, contradicting earlier reports of rarity.
• Distinct SE patterns (punctate, linear, confluent, conglomerate, ring-like) were identified, reflecting heterogeneous underlying pathology.
• Immunodeficiency-associated lymphomas showed higher prevalence of hemorrhage and necrosis-related SE compared to immune-competent cases.
• Secondary CNS lymphoma cases typically demonstrated parenchymal involvement with characteristic MRI features differing from primary CNS lymphoma.
• Pre-treatment corticosteroid administration did not preclude detection of SE, supporting MRI utility in initial diagnostic workup.
• Multifocality and diverse morphological patterns on MRI correlated with lymphoma subtype and immune status.

Clinical Implications

Recognition of susceptibility effects on T2*WI and SWI in CNS DLBCL can aid in differentiating lymphoma subtypes and immune-related variants, guiding biopsy timing and avoiding premature corticosteroid use. MRI patterns of SE and lesion morphology provide valuable diagnostic clues for primary versus secondary CNS lymphoma and immunodeficiency-associated cases. Incorporating susceptibility-based imaging sequences is recommended in routine CNS lymphoma MRI protocols.

Conclusion

This comprehensive MRI analysis demonstrates that susceptibility effects are common in CNS large B-cell lymphomas and vary with lymphoma subtype and immune status. These findings enhance neuroradiological characterization, supporting improved diagnostic accuracy and clinical management.

References

1. WHO Classification of Hematolymphoid Tumors/2022 -- Primary large B-cell lymphomas of immune-privileged sites
2. University Center for Tumor Diseases Frankfurt/2023 -- Retrospective DLBCL MRI Cohort Study
3. Neuroradiology Literature/2010-2023 -- Susceptibility Effects in CNS Lymphomas