Mamillopontine distance

The mamillopontine distance, also spelled mammillopontine, is defined as the distance between the inferior aspect of the mammillary bodies to the superior aspect of the pons.

Measurement

The mamillopontine distance is measured on midsagittal T1WI MRI from the anterior root of the mammillary body to the top of the pons parallel to the anterior mesencephalon or the shortest distance between the center of the mammillary bodies and the upper surface of the pons.

Interpretation

In normal individuals, it should be >5.5 mm .

It is decreased in conditions that either depress the floor of the third ventricle or change the position of the brain within the intracranial cavity. Such conditions include:

• intracranial hypotension: it is one of the helpful quantitative signs helpful in improving the accuracy of MRI diagnosis
• hydrocephalus: as one of the morphological changes at mid-sagittal MRI