Atypical MRI findings of venous sinus thrombosis in pregnancy: clinical significance relating to episodic vascular headache.

Two cases of headache during pregnancy were associated with MRI findings suggestive of venous sinus thrombosis. The findings, however, were atypical, and of uncertain clinical significance. Venous sinus thrombosis typically does not occur during the first and second trimesters (less than 10 percent of reported cases). Thus, these two cases are doubly unusual. The correct significance of these equivocal MRI findings of possible venous sinus thrombosis must be understood so that unnecessary and potentially harmful therapies are not employed, and so that appropriate management of what may otherwise be a typical vascular headache syndrome may be undertaken.