The orbitomeatal line, also known as the canthomeatal line, was the traditional axial plane used for CT of the brain. It was easily identified on the inspection of the patient's head when tilting the gantry or patient's head to achieve a standard axial plane.
The orbitomeatal line was defined as running from the outer canthus of the eye to the midpoint of the external auditory meatus 1,2.
Gradually this plane is falling out of favour in CT for a number of reasons:
- significantly elevated doses to the lens compared to planes that avoid the orbit 1
- aligning CT axial plane to the AC-PC line which is standard in MRI 2,3
- 1. Yeoman LJ, Howarth L, Britten A, Cotterill A, Adam EJ. Gantry angulation in brain CT: dosage implications, effect on posterior fossa artifacts, and current international practice. Radiology. 184 (1): 113-6. doi:10.1148/radiology.184.1.1609066 - Pubmed
- 2. Y.I. Kim, K.J. Ahn, Y.A. Chung, B.S. Kim. A New Reference Line for the Brain CT: The Tuberculum Sellae-Occipital Protuberance Line is Parallel to the Anterior/Posterior Commissure Line. American Journal of Neuroradiology. 30 (9): 1704. doi:10.3174/ajnr.A1676 - Pubmed
- 3. Kenneth L. Weiss, Judd Storrs, Jane L. Weiss, William Strub. CT Brain Prescriptions in Talairach Space: A New Clinical Standard. American Journal of Neuroradiology. 25 (2): 233. Pubmed