Because of the broad clinical spectrum it is often difficult to establish the diagnosis of cerebral venous thrombosis (CVT). Combined MRI/MRV and contrast-enhanced CT are the most accurate methods for diagnosis of CVT. However these methods are often not available on an emergency basis. This stresses the need for additional widely available tests such as coagulation markers to exclude CVT. The diagnostic value of D-dimer levels for the exclusion of CVT is still under debate. Other potential coagulation markers have not been systematically investigated. The investigators aim to assess the overall accuracy of D-dimer values and FXIII activation peptide (FXIII-AP), using a newly developed ELISA test, to exclude CVT in patients with clinical suspicion of CVT. Consecutive patients with clinical suspicion of CVT at the emergency department of the University Hospital Bern will be included in this study over a two year period. All included patients will receive standard care applied by the treating physician who will follow international recommendations. Patient involvement in the study shall not influence any treatment decision. On admission patients will undergo a complete diagnostic work-up, including a clinical neurological examination, standard laboratory examination including D-dimer values, and brain contrast CT and/or MRI/MRV. In addition, plasma FXIII-AP will be analyzed. FXIII-AP will be analyzed at the Hemostasis Research Laboratory, Department of Hematology, University of Bern, based on a newly developed highly sensitive and specific ELISA method. The investigators will be blinded for the clinical symptoms and diagnosis of the patient. The study will be conducted according to the guidelines of the STARD (Standards for Reporting Diagnostic Accuracy) initiative.