Augmenting Medical Neuroanatomy Cadaveric Dissection with DiceCT Imaging

Abstract

Dissection of the brain and central nervous system for medical education is an informative but often wholly destructive process, leaving students with little reference material from which to review neural structures and their anatomical relationships. Here, we explore the use of diffusible iodine contrast enhancement followed by high‐resolution microCT (diceCT) to combine destructive physical dissection with more permanent digital dissection. DiceCT methods render soft tissues radiodense to X‐rays, emulating the tissue discrimination of magnetic resonance imaging (MRI). Such imaging studies provide students the opportunity to identify and interpret pathological findings in ex‐vivo neural tissues. To identify best‐practices for incorporating diceCT imaging into the medical neuroanatomy lab, we stained formalin‐preserved human brains with three concentrations of iodine (3, 4, and 5% aqueous I2KI) for 3 weeks, replacing the iodine solutions after the first and second weeks. All brains were microCT scanned at 63‐micron resolution, and the resulting image stack was rendered in Avizo version 2019.2. The stained brains were then bisected, and one hemisphere was de‐stained for 4 weeks by alternating baths of 1% sodium thiosulfate with deionized water each on a week‐long cycle. All concentrations of iodine were effectively de‐stained using this protocol. Students then performed comparative physical dissections on never‐stained, stained only, and stained‐then‐de‐stained brains, and comparative digital dissections were performed on brains of each iodine concentration. In physical dissection, stained only brains had few advantages—although the dark iodine stain enhanced some fiber tracts, specimens were smaller, physically difficult to manipulate, and harbored subcortical nuclei (e.g. the basal ganglia) that were more difficult to identify. Dissection of never‐stained and de‐stained brains was found to be equivocal, with de‐stained brains regaining much of their original size. In digital dissection, the 5% aqueous I2KI solution provided the clearest discrimination between structures, and pathologies such as age‐related atrophy and hydrocephalus were apparent. In addition to leaving a more permanent imaging study record of nervous tissue specimens, digital dissection allows for 3D printing of brain regions. These benefits were positively received by students, and we recommend incorporation of rapid, inexpensive tissue staining and tomography to enhance participation and clinical skills in the anatomy lab. Support or Funding Information Federal Work Study, OSU Center for Health Sciences