It has already been shown that PWI provides valuable information concerning tumour perfusion, facilitating the preoperative classification and grading of gliomas [3–6]. Our data stress the role of PCT in the preoperative differential diagnosis of primary central nervous system lymphomas (PCNSL) from high-grade gliomas. PCNSL, a discrete histopathological entity, constitute up to 6% of malignant central nervous system (CNS) tumours [20]. Although PCNSL present certain characteristic magnetic resonance imaging (MRI) findings, it can be difficult or even impossible to differentiate them, on the basis of imaging features, from high-grade gliomas on standard CT or MRI, because of their diffuse infiltrative growth [21, 22]. Histopathologically, contrary to high-grade gliomas, PCNSL are characterised by the absence of neovascularisation. Our results show that lymphomas can be differentiated from high-grade gliomas by comparing CBV and CBF parameters using PCT. Both histopathological entities presented significantly higher permeability values compared with normal brain parenchyma, but only high-grade gliomas presented with significantly higher values of regional CBV and CBF parameters than those of normal cerebral parenchyma. Our results are comparable with those previously reported for a series of patients who underwent PWI [19]. Because PCNSL and high-grade gliomas require different therapeutical management and differ in prognosis, precise diagnosis is crucial [20, 23].