MR imaging of the yucatan pig head and neck vasculature.
To evaluate the cerebral venous drainage system of the swine as a probable model to test whether extracranial venous abnormalities may play a role in neurodegenerative diseases as reported recently in multiple sclerosis. Three Yucatan micropigs, 5 to 7 months old, were scanned with a comprehensive MRI protocol at 3 Tesla. The vascular anatomy of the head and neck was imaged using conventional and angiographic MR sequences. Phase-contrast MR images were collected at multiple levels of the neck and intracranial space to monitor flow. Three large cervical veins were observed; the external jugular vein draining the olfactory and gustatory tissues; the internal jugular vein (IJV) draining the cavernous sinus as well as surrounding soft tissues in the neck; and the ventral vertebral venous plexus (VVVP) surrounding the dural sac and paraspinal region. The majority of the cerebral blood flow in the pig appears to drain through the VVVP. Flow through the IJV comprised a nondominant component. Anastamoses were observed connecting the major veins of the neck bilaterally. The dominance of outflow from the brain to the VVVP may be analogous to the typical dominance of the IJVs in humans in the supine position.