Final answer:
Pericardial cysts can have a variable signal intensity on T1 weighted imaging due to proteinaceous material within the cyst.
Step-by-step explanation:
Most pericardial cysts are low signal on a T1 weighted image, but they can be intermediate or bright signal on T1 weighted imaging due to proteinaceous material. Proteinaceous material within the pericardial cyst can alter the signal intensity on a T1 weighted image. This can occur when the cyst contains protein-rich fluid or blood products.