Sedat Aydoğdu, Mustafa Koplay, Emrullah Eken

Sexual dimorphism in the sheep corpus callosum using 3 tesla MRI

Aim: This study aims to determine the morphological and morphometric differences of the corpus callosum in terms of sex using high-resolution images obtained from formalin-fixed sheep brains by 3T Magnetic Resonance Imaging (MRI). Materials and Methods: In the study, a total of 18 adult healthy Akkaraman sheep brains (9 females and 9 males), which had no anomaly and were fixed with formaldehyde, were used. Morphometric measurements in sheep brains were performed on T2-weighted images obtained from 3T MRI. First, the midsagittal cross-sectional area of the corpus callosum was calculated using MIMICS. Before morphometric measurements, images were converted from DICOM format to NIfTI format in the MRcronGL. Then, the normalization of the images were performed using the standard template in the ITK-SNAP. After that images were opened in the ITK-SNAP, and morphometric measurements were performed in genu corporis callosi, truncus corporis callosi, and splenium corporis callosi. Results: In sheep, the lower surface of the truncus corporis callosi, which forms the roof of the ventriculus lateralis, was more concave than dog and cat, and flatter than human, horse and rabbit. There was no sexual dimorphism in corpus callosum length, midsagittal corpus callosum cross-sectional area, genu corporis callosi width, truncus corporis callosi width and splenium corporis callosi width. Similarly, no sexual dimorphism was observed in the ratio between midsagittal corpus callosum cross-sectional area and brain weight and volume. However, it was observed that the ratio between surface area and volume was very close to the difference frequently encountered in this parameter in studies conducted in humans and other mammals. Conclusion: It is thought that the findings obtained from healthy sheep brains in this study can be used in neurodegenerative disease models created in sheep in neuroscience studies and experimental studies.

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Author Contributions Motivation / Concept: Emrullah Eken Design: Emrullah Eken, Sedat Aydoğdu Control/Supervision: Emrullah Eken Data Collection and / or Processing: Emrullah Eken, Mustafa Koplay
Analysis and / or Interpretation: Emrullah Eken, Sedat Aydoğdu Literature Review: Sedat Aydoğdu
Writing the Article : Emrullah Eken, Sedat Aydoğdu Critical Review: Emrullah Eken, Mustafa Koplay The Ethics Committee approved the study procedure of Selçuk University Faculty of Veterinary Medicine (Date: 25/04/2019 and Decision no: 2019/38)