Table 1.

Findings obtained using nonconventional magnetic resonance techniques that are useful for differentiating PCNSL from mimic lesions.

	Primary central nervous system lymphoma
Diffusion-weighted imaging	Restricted water molecule movement (typically homogeneous in immunocompetent patients)
Apparent diffusion coefficient value	≤1.1 × 10−3 mm2/s
Proton magnetic resonance spectroscopy	Increased lipid and lactate levels (0.9–1.3 ppm) Increased choline levels and decreased N-acetylaspartate levels
Dynamic contrast-enhanced magnetic resonance imaging	High permeability of the blood-brain barrier may be observed
Dynamic susceptibility contrast magnetic resonance imaging	Lower relative cerebral blood volume (<1.75) than in high-grade gliomas or metastases A high percentage of signal-intensity recovery above the baseline would favor a diagnosis of lymphoma.

Note: All of these features should be carefully interpreted in immunocompromised patients due to the occurrence of necrosis and hemorrhage and the considerable overlapping features between primary central nervous system lymphoma and brain infections, particularly early toxoplasmosis.