IVL: intravascular lymphoma, MRI: magnetic resonance imaging, MRA: magnetic resonance angiography, CT: computed tomography, EEG: electroencephalogram, DSA: digital subtraction angiography, CSF: cerebrospinal fluid, LDH: lactate dehydrogenase, ESR: erythrocyte sedimentation rate, CRP: C-reactive protein, sIL-2R: soluble interleukin-2 receptor, PCR: polymerase chain reaction, IPH: intraparenchymal hemorrhage, SAH: subarachnoid hemorrhage, FDG: fluorodeoxyglucose, PET: positron emission tomography, CAP: chest, abdomen, and pelvis, CTAP: computed tomography arterial portography. This evidence concerns the gene CRP and subarachnoid hemorrhage.