Enlargement of the vascular lumen means enlargement of the perivascular lymphatic space. Enlarged perivascular lymphatic space is a normal anatomical structure within the body’s nervous system and has certain immune functions. The tissue structure and anatomy of the body can be shown in a magnetic resonance imaging test, which is able to detect the expansion and increase of the perivascular space in the body as well as follow a variety of neurological disorders. Enlargement of the perivascular lymphatic space occurs commonly in hydrocephalus, dementia, central nervous cryptococcal infections, cerebral white matter lesions, and developmental brain disorders in children. The enlarged perivascular lymphatic space is usually connected to the body’s soft meninges, whereas the perivascular space in the cerebral hemispheres does not communicate directly with the subarachnoid space. The perivascular space generally serves as a conduit for the drainage of interstitial fluid from brain tissue, and the space contains a large protein component. If there is a problem with enlarging the vascular space, it is recommended to go to the hospital immediately to check the cause of the problem, and then treat the symptoms according to the cause of the problem.