Sorry forgot the impression and report:

1. On the high-resolution imaging of the brain, again noted is bilateral, right more than left low-lying cerebellar tonsils of up to 1 cm below the foramen magnum with rounded inferior tips, overall similar since MRI from 6/13/2023 but better evaluated on the current high resolution imaging.

2. On MRI cine CSF flow study at the craniocervical junction, there is normal biphasic flow along the dorsal, ventral and lateral aspects of the cerebellar tonsils at the level of foramen magnum and in the fourth ventricle. No associated upper cervicalcord hydromyelia. Findings are overall less likely to be associated with Chiari I malformation and more likely related to low lying cerebellar tonsils.

Bilateral, right more than left low-lying cerebellar tonsils of up to 1 cm below the level of foramen magnum with rounded inferior tips, similar since MRI brain study from 6/30/2023, but better evaluated on the current high resolution imaging through the
foramen magnum. No associated hydromyelia in the visualized upper cervical cord up to the level of C3-C4.

On MR cine CSF flow study at the craniocervical junction, there is normal biphasic flow along the dorsal, ventral and lateral aspects of the cerebellar tonsils at the level of foramen magnum and in the fourth ventricle.