Limits of 8-Tesla magnetic resonance imaging spatial resolution of the deoxygenated cerebral microvasculature

Abstract

Purpose: To quantify the minimum magnetic resonance imaging (MRI) spatial resolution of the visible deoxygenated microscopic vessels of the human brain at 8 T.

Materials and methods: This study compared 8-T gradient echo (GE) images of a human cadaver brain having an in-plane resolution of 195 x 195 microm to corresponding digital photographs of 205 cryomicrotome sections of the same cadaver brain, along with summed images of 25 contiguous cryomicrotome sections. One-millimeter-thick GE images of a 1-cm-thick unfixed whole coronal brain section were acquired using techniques similar to those commonly utilized for 8-T human imaging in vivo.

Results: There was excellent MR visualization of the deoxygenated microscopic vessels within the brain down to a resolution of approximately 100 microm.

Conclusion: By taking advantage of magnetic susceptibility-based blood oxygenation level-dependent (BOLD) contrast, deoxygenated microscopic blood vessels smaller than the pixel dimensions used for imaging can be visualized using a whole-body 8-T MRI system.