Microfocal CT: a method for evaluating murine cranial sutures in situ

Area of Science:

• Biomedical imaging
• Craniofacial development
• Mouse models in research

Background:

• The murine posterior frontal (PF) suture is unique as it fuses postnatally, unlike other mouse sutures.
• Histology is the standard for suture analysis but requires animal sacrifice, limiting longitudinal studies.
• Current knowledge of suture fusion kinetics relies on fragmented data from multiple animals and time points.

Purpose of the Study:

• To evaluate microfocal computed tomography (micro-CT) as a noninvasive imaging technique for mouse cranial sutures.
• To assess the feasibility of repeatedly imaging sutures in vivo using micro-CT.
• To compare micro-CT imaging of sutures with traditional histology and gross specimens.

Main Methods:

• Micro-CT scans were performed on a 45-day-old mouse cranium, generating 3D volumetric reconstructions.
• Holes were drilled near the PF and sagittal sutures for spatial reference.
• Micro-CT images were compared with gross specimens and histological sections of the sutures.

Main Results:

• Micro-CT accurately rendered drilled holes, correlating well with gross and histological findings.
• The sagittal suture was consistently identified as patent (open) by both micro-CT and histology.
• The PF suture, identified as fused by histology, appeared incompletely fused by micro-CT, with regional differences in fusion extent.

Conclusions:

• Micro-CT successfully imaged mouse cranial sutures in situ, demonstrating potential for noninvasive analysis.
• Discrepancies between micro-CT and histology in PF suture fusion may relate to differences in detecting bone morphology versus tissue density.
• Micro-CT is a promising tool for longitudinal studies of cranial suture development and fusion in vivo.