Analysis of brain volume variation post-mortem before and after fixation in formalin through the principle of Archimedes compared to calculation by computer graphics

• Grant number: 13/27016-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2014
• End date: July 31, 2015
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Erich Talamoni Fonoff
• Grantee: Danilo Costa Barbosa
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The advent of magnetic resonance imaging (MRI ) allowed the noninvasive anatomic and physiological study of the human brain . However , this technique has its limitations in representing spatially certain brain structures . This difficulty is related to nonlinearity and imperfections of the magnetic field created by the device generating the intrinsic distortion of RM .Thus , the detailed study of brain structure is required by histological methods . However, for such it is necessary to subject the body to the mounting process in 10% formalin , thus to condition him to histological processing. However , the setting is causing great distortion and shrinkage of brain volume.In order to evaluate the changes generated during fixation in formalin , Schulz et al . used MRI to demonstrate record fields distortion present in the brain after formalin fixation . However , in their analysis the limitations of MRI in measuring volume were not considered in their results .The objective of this project is to investigate what is the reliability of MRI in the evaluation of the variation of brain volume observed during the formalin fixation process .To do so , we will use the MR images before and after the use of formaldehyde in the brain and reconstruct them three-dimensionally with computer graphics software FreeSurfer , and compare the obtained volumetric calculation in software with the volume found with Archimedes' principle.