Table 3.

Data on 636 patients with isolated headache

	CVT		No CVT
	D-dimer raised	D-dimer normal	D-dimer raised	D-dimer normal
Tardy et al., 2002	6	0	0	17
Kosinski et al., 2004	20	0	27	244
Meng et al. 2014	15	1	2	155
Alons et al., 2015	3	0	63	83
Total	44	1	92	499