Colloid cyst: diffusion MR imaging findings.

Colloid cysts usually have viscid gelatinous material or denser content. In an adult patient with a colloid cyst, diffusion magnetic resonance (MR) imaging was applied to detect its features with this sequence that if its viscous content may lead to a hyperintense appearance (decreased diffusion pattern) on b= 1000 sec/mm(2) images similar to epidermoids. The colloid cyst had hypointense signal on the b= 1000 sec/mm(2) image. The ADC map had more information that the ADC value of the cyst was 1.58 x 10(-3) mm(2)/sec. This value was apparently higher than that of normal cerebral parenchyma, and was apparently lower than that of CSF. These diffusion MR imaging features of the colloid cyst are consistent with an elevated diffusion pattern in contrast to epidermoids.