The mamillopontine distance or pontomamillary distance is defined as the distance between mamillary bodies to the superior aspect of the pons. When the mamillopontine distance is less than 5.5mm, it is an important indicator to diagnose intracranial hypotension.

Intracranial hypotension can be a challenging diagnosis because of the varied spectrum of clinical symptoms and is sometimes misdiagnosed as migraine headaches, meningitis, or a psychogenic disorder which can delay effective treatment.

the cause of intracranial hypotension may be identifiable, such as a sequela of trauma from skull base or facial fracture, craniospinal surgery, or lumbar puncture.

The clinical hallmark of intracranial hypotension is orthostatic headache.

Imaging is a critical part of identifying the diagnostic criteria for intracranial hypotension. There are five typical but variably present imaging characteristics: dural (pachymeningeal) enhancement, venous engorgement, pituitary hyperemia, subdural collections, and brainstem slumping.

Reference:

DOI:10.2214/AJR.12.8611 Intracranial Hypotension: Improved MRI Detection With Diagnostic Intracranial Angles

Rezaee, A., Smith, D. Mamillopontine distance. Reference article, Radiopaedia.org. (accessed on 31 Mar 2022) https://doi.org/10.53347/rID-43163