True or false: Pineal cysts do not enhance.
False(ish) as approximately 60% of lesions show some peripheral enhancement, usually thin (< 2 mm) and confined to the rim (either complete or incomplete). In atypical cases enhancement may be nodular, or there may be evidence of previous haemorrhage into the cysts.
What is one of the imaging pitfalls in the following scenario: Patient is administered contrast for the last couple of sequences. He complains of 'funny feeling' and is taken out of the magnet. After review by the radiologist and a cup of tea he is happy to return to the scanner to have his post contrast scans.
If post contrast imaging is delayed (60 - 90min), gadolinum may diffuse into the cyst fluid and may lead to the mass appearing solid.
The pineal cyst (yellow dotted line) displaces pineal calcification (yellow arrow) inferiorly. The internal cerebral veins (blue) are located above the cyst easily seen on sagittal and coronal images. They drain into the vein of Galen (red) just below the splenium of the corpus callosum (SCC).
Although the cyst is of near-CSF intensity on T1 and T2 images, on FLAIR it does not fully attenuate - the difference is easily seen when comparing the cyst to the CSF in the lateral ventricles ( * ).