CT Perfusion in the differential diagnosis of glioblastomas and primary central nervous system lymphomas

To compare perfusion parameters of glioblastomas and primary central nervous system lymphomas (PCNSL) using CT perfusion (CTP) and to assess the diagnostic performance of this technique for their preoperative differential diagnosis.

This single-center retrospective study included CTP data from 122 patients (57 with PCNSL and 65 with glioblastoma) examined at our hospital between 2006 and 2026. All diagnoses were histologically verified; no patient received chemotherapy, corticosteroids or radiotherapy prior to CTP. Imaging was performed on a 64-slice Optima 660 scanner (GE Medical Systems) using a prolonged perfusion protocol. Absolute (CBF, CBV, MTT, PS) and normalized (nCBF, nCBV, nMTT, nPS) perfusion parameters were obtained. The Mann-Whitney U test, Spearman correlation and ROC analysis were applied for statistical comparison.

Glioblastomas demonstrated significantly higher CBF and CBV and lower MTT and PS values than PCNSL; the same pattern was observed for the normalized parameters. PS (AUC = 0.93), nPS (AUC = 0.90), nCBF (AUC = 0.91), nCBV (AUC = 0.90), CBF (AUC = 0.88) and CBV (AUC = 0.88) showed the highest diagnostic performance, whereas MTT and nMTT were less informative (AUC = 0.69-0.72).

CTP is a highly informative non-invasive quantitative imaging tool for the preoperative differentiation of glioblastomas and PCNSL. The inclusion of normalized perfusion parameters improves reproducibility and supports use in routine clinical practice and multicenter studies. CTP can be recommended whenever conventional CT and MRI fail to reliably distinguish these tumors.