New MR perfusion features in primary central nervous system lymphomas: pattern and prognostic impact.

Purpose: Some MR perfusion features predict overall survival (OS) and progression-free survival (PFS) in glioblastomas. Prognostic value of MR perfusion in primary CNS lymphomas (PCNSL) remains unexplored being the aim of this investigation.

Methods: We retrospectively analyzed 3Tesla dynamic susceptibility contrast MR perfusion in 37 pre-surgical PCNSL for normalized regional cerebral blood volume rCBV and rCBV and for a PCNSL-typical shoulder-like increase of the time-signal intensity curve ("TSIC-shoulder"), indicating moderate vessel permeability. These MR perfusion features, tumor and edema size, number of lesions and patient characteristics were correlated with OS and PFS.

Results: Only patient's age was prognostic for OS (p = 0.0037) and PFS (p = 0.0088). 23 PCNSL had the TSIC-shoulder, a middle-sized diameter (39.5 ± 10.8 mm), volume (15.7 ± 11.3 ml), peritumoral edema (23 ± 8.7 mm) and moderately increased rCBV and rCBV (1.7 ± 0.5; 3.9 ± 1.2). Seven PCSNL with the TSIC-shoulder presented a sun-like pattern ("rCBV-sun") with a rim of marginally high rCBV. These unifocal PCNSL were larger (43 ± 11.2 mm; 25.62 ± 19.2 ml), with more peritumoral edema (32.8 ± 7.6 mm) and lower CBV (0.8 ± 0.3) and rCBV (2.2 ± 0.7), compared to the remaining six multifocal PCNSL without the TSIC-shoulder (26.3 ± 8.3 mm; 4.7 ± 4 ml; 16.3 ± 6.4 mm; 2.4 ± 1.6; 4.4 ± 2.3).

Conclusions: Only patient age was predictive for OS and PFS of PCNSL; MR perfusion parameters and features were not. Most PCNSL revealed the TSIC-shoulder, moderate size, peritumoral edema and rCBV increase. However, larger, solitary PCNSL additionally had a rCBV-sun pattern and more edema, maybe due to a centrifugal vessel proliferation, whereas smaller, multifocal PCNSL contain apparently more concentrated and less permeable blood vessels represented by higher rCBV, no TSIC-shoulder and less edema.