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Colloid Cyst (CC)

Last Updated: October 1, 2018

Figure 1: Because colloid cysts are typically filled with a highly proteinaceous fluid, they are often dense on CT (top row left) and hyperintense on T1WI (top row right). Colloid cysts should have no internal enhancement on T1WI post contrast images (bottom). This colloid cyst is in the classic location at the foramen of Monro.


Figure 2: Sagittal (top row left) and axial (top row right) T1 images demonstrate a low signal intensity colloid cyst at the foramen of Monro. The cyst has a central T1 hyperintense focus that represents inspissated proteinaceous debris. The cyst is bright on T2 with low signal intensity proteinaceous debris that is sometimes referred to as the “black hole” effect (middle row left). The cyst remains predominantly hyperintense on FLAIR, indicating its conten...