Type:
Educational Exhibit
Keywords:
Pathology, Education and training, Diagnostic procedure, MR, CT, Neuroradiology brain
Authors:
S. Moawad1, S. Hasan2, H. Semaan3, S. pinsky2, H. Elsamaloty3; 1Toledo, Ohio/US, 2Toledo/US, 3Toledo, OH/US
DOI:
10.1594/ecr2018/C-1187
Background
- The pineal gland is a small ( ~ 7mm) structure located at the level of the midbrain,
between the thalami at the posterior aspect of the third ventricle (Fig. 1).
- The internal cerebral veins and vein of Galen are located superior and posterior to the pineal gland,
respectively.
These anatomic relationships can be helpful to determine if a mass is pineal or extra-pineal.
-
The principal neuronal cell of the pineal gland is the pinealocyte; a modified retinal neuronal cell that is innervated by the sympathetic plexus originating in the retina.
-
The main product of the pineal gland; melatonin,
modulates the sleep/wake cycle.
-
The pineal gland does not have a blood-brain barrier.
-
Mass lesion in the pineal region may cause:
*Compression of the midbrain.
*Compression of the cerebral aqueduct of Sylvius producing obstructive hydrocephalus.
*Compression of the tectal plate producing Parinaud syndrome (vertical gaze palsy),
pupillary light dissociation,
and nystagmus.
-
Physiologic calcification is usually seen after the age of 10 years.
A calcified pineal gland before the age 6 years of age should be viewed with suspicion for adjacent tumor.
Fig. 1: Normal Anatomy
Imaging protocol
The pineal region is best imaged with MRI although CT,
angiography,
and ultrasound (in infants) also play a role.
Thin section high-resolution imaging in all three planes is crucial to determine the relationship of the mass with the adjacent structures.
A typical protocol would include:
- Sagittal T1-weighted and T2-weighted (high resolution)
- Pre and Postcontrast T1-weighted axial and coronal
- FLAIR
- DWI
- SWI/Gradient echo (to assess for presence of calcification)