Background and purpose To test the hypothesis that sporadic cerebral cavernous malformations (CCMs) are systematically associated with venous malformations (VMs) using susceptibility weighted imaging (SWI) at 7 Tesla (T) field MRI.

Methods A prospective unselected series of 20 patients with symptomatic or asymptomatic sporadic CCM diagnosed using 1.5 T MRI was additionally scanned using high resolution (250 µm² in-plane) SWI at 7 T MRI. Imaging data were analysed to examine the presence and formation of CCM associated venous vessel structures. Interobserver agreement was assessed using kappa statistics.

Results In the 20 patients harbouring 23 CCMs, a solitary or multiple venous drainage was found in all lesions. A ‘typical’ VM was found in seven lesions. In the other cases, associated abnormal venous structures were also depicted although they appeared structurally different. Excellent interobserver agreement was achieved (95% confidence interval 0.92 to 0.99).

Conclusions Our data support previous assumptions that sporadic CCMs are systematically associated with local venous abnormalities involving larger outflow vessels. However, the typical appearance of a VM was not confirmed in all cases. The role of the venous environment in the pathomechanism of CCMs remains unclear.