Abstract
Background All brain surgery requires some degree of iatrogenic trauma to healthy tissue. Minimally
invasive approaches to brain tumors offer the potential of decreasing this trauma
compared with conventional approaches. However, there are no validated radiologic
models to examine axonal damage after minimally invasive entry into the brain.
Objective To present a cadaveric model of brain cannulation using fractional anisotropy measurements
obtained from diffusion tensor magnetic resonance imaging (MRI). Two different methods
of access are compared.
Methods Freshly harvested unfixed cadaveric brains were cannulated using both direct and
indirect (i.e., dilation followed by cannulation) methods. Specimens were subjected
to 68-direction diffusion tensor imaging scans and proton-density imaging. Fractional
anisotropy (FA) data from a region of interest surrounding the entry zone was extracted
from scans using imaging software and analyzed.
Results FA values were significantly higher following indirect cannulation (less invasive
method) than they were following direct cannulation. FA values for undisturbed brain
were significantly higher than in either of the cannulated groups, suggesting an inverse
relationship between FA values and brain injury.
Conclusion Axonal damage following brain cannulation can potentially be evaluated by FA analysis
in a cadaveric model. These data may lead to an MRI-based model of iatrogenic brain
injury following tumor surgery. Future studies will focus on histologic analysis and
clinical validation in live tissues.
Keywords
diffusion tensor imaging - cadaveric model - minimally invasive surgery - brain surgery
