Pineal Gland

Pineal Gland

The pineal gland is a small endocrine structure located near the centre of the brain. Although it measures only a few millimetres in size, it plays an important role in regulating the body’s circadian rhythm and sleep–wake cycle through the production of melatonin. By helping to synchronize biological processes with the day–night cycle, the pineal gland contributes to sleep regulation, hormonal balance, and overall physiological homeostasis. Because sleep quality and circadian regulation are important aspects of neurological health and quality of life, there is increasing interest in understanding the potential effects of radiation exposure to the pineal gland. Accurate delineation may therefore be relevant for both clinical and research applications.

Co-registration with a T1-weighted MRI is recommended to facilitate accurate identification of the structure. The pineal gland is a small, oval-shaped structure typically measuring approximately 8 mm in diameter. It is located in the midline within the quadrigeminal cistern and can usually be identified on both MRI and CT imaging.

Key anatomical landmarks include:

• Anterior border: the posterior aspect of the third ventricle.
• Superior border: the splenium of the corpus callosum.
• Posterior border: the vein of Galen region.
• Inferior border: the tectal plate (quadrigeminal plate) of the midbrain.

In adults, the pineal gland frequently contains physiological cysts or calcifications. Calcifications are particularly well visualized on CT imaging and can often facilitate identification of the gland. Given its small size and close proximity to surrounding vascular and ventricular structures, careful review in multiple imaging planes is recommended to ensure accurate delineation.

The accompanying video demonstrates a step-by-step approach for identifying and contouring the pineal gland using anatomical landmarks on MRI and CT. This educational resource is intended to support consistent, accurate, and reproducible delineation for clinical and research applications.

Please site as follows:

Hofstede, D., Di Perri, D., Roelofs, E., Postma, A., Troost, E., & Eekers, D. EPTN International Neurological Contouring Atlas (INCA) instruction videos. CancerData, 2022. doi:10.17195/candat.2022.02.1