Neuroimágenes estructurales y funcionales en la caracterización del linfoma del SNC

Structural and functional imaging for the characterization of CNS lymphomas Purpose: To show the imaging patterns of primary or secondary involvement of the Central Nervous System (CNS) in cases of lymphoma with emphasis in the contribution of spectr oscopy. Material and methods: 25 cases (16 males and 9 females) wer e retrospectively reviewed using a 1.5T magnetic resonance unit. The patients had a histological diagnosis of NonHodgkins lymphoma with CNS involvement. The cases were studied with conventional MR with contrast and functional images were obtained with spectroscopy through a multivoxel technique using intermediate and short echo sequences Results: Three main patterns of presentation were identified: parenchymal, meningeal and cranial nerve involvement. Additionally some characteristic findings wer e detected such as the involvement of perivascular spaces. Conventional MRI was not conclusive in the characterization of several tumors. In such patients spectroscopy proved to be very useful. The most significant findings both in the primary tumors as well as in the secondary lesions were the lipid and choline peaks. The choline peak was in some cases identified as the dominant metabolite, particularly in the short TE echo sequences. No differences were found between the spectroscopic pattern of primary and systemic lymphomas. Conclusion: CNS lymphomas are tumors with a wide range of radiological patterns. This characteristic cr eates difficulties to characterize them correctly during the pre-surgical phase with conventional MRI alone. MR Spectroscopy may be useful in such cases by demonstrating the lipid peak. This finding only seen in deep intra-axial tumours demonstrated by contrast enhancement supports the presumption of lymphoma and may lead to changes in therapeutic or surgical strategy.