MR imaging of the yucatan pig head and neck vasculature.

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Correlation of putative iron content as represented by changes in R2* and phase with age in deep gray matter of healthy adults.

PURPOSE: To establish a correlation between putative iron content using susceptibility weighted imaging (SWI) phase and T2* weighted magnitude values in the basal ganglia and the thalamus as a function of age in healthy human brains. MATERIALS AND METHODS: One hundred healthy adults (range, 20-69 years; mean, 43 years) were evaluated for this study using a gradient echo sequence. The original magnitude and high pass filtered phase data were analyzed as proxy variables for iron content in the substantia nigra, red nucleus, globus pallidus, putamen, caudate nucleus, thalamus, and pulvinar thalamus. Each structure was broken into two parts, a high iron content region and a low iron content region. RESULTS: Both magnitude and phase data showed an increase in putative iron content with age. However, the high iron content region revealed two new pieces of information: both the average iron content per pixel and the area of high iron increased with age. Furthermore, significant increase in iron uptake as a function of age was found past the age of 40. CONCLUSION: A two region of interest analysis of iron is a much more sensitive means to evaluate iron content change over time. Contrary to the current belief that iron content increases level off with age, the putative iron deposition in the high iron content region is seen to increase with age.