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Type:
Educational Exhibit
Keywords:
Ischaemia / Infarction, Diagnostic procedure, MR-Diffusion/Perfusion, MR, Neuroradiology brain, Anatomy
Authors:
J. L. Nix, I. Craven, S. Currie, J. Macmullen-Price, D. J. Warren, H. Nejadhamzeeigilani, T. Buende Tchokouako; Leeds/UK
DOI:
10.1594/ecr2017/C-1356
Background
Small brainstem infarcts are responsible for comparitively significant patient morbidity,
due to the eloquent areas involved[1].
Patients present with a collection of symptoms and signs which relate to the precise location of the infarct.
The main eponymous brainstem infarction syndromes were named prior to the advent of cross sectional imaging,
and are classified as either medial or lateral,
within the midbrain,
pons and medulla. Claude and Weber syndromes involve the medial midbrain whilst Benedikt involves the lateral midbrain.
Foville and Marie Foix syndromes involve the medial and lateral pons respectively.
Dejerine and Wallenberg syndromes involve the medial and lateral medulla respectively.
CT has poor sensitivity for acute posterior fossa ischaemic stroke.
As much as two thirds of DWI (diffusion weighted imaging) proven brainstem infarcts are not apparent on unenhanced CT[2] Consequently,
misdiagnosis of posterior fossa infarcts is common[3].
Radiologists need to have a good working knowledge of brainstem anatomy and consider brainstem infarction when patients present with specific symptoms related to the nuclei,
nerves and tracts involved,
in order that optimal acute stroke treatment can be delivered.
The complex anatomical arrangement within the brainstem of multiple cranial nerve nuclei and ascending and descending nerve tracts can be better understood by correlating clinical symptoms occurring in brainstem infarction syndromes with the areas affected on MR imaging.
CT is important to exclude alternate pathology and identify contraindications of acute stroke treatments[4].
If CT is negative it is important to proceed to MRI with DWI in a timely fashion in patients presenting with brainstem syndromes to detect small acute infarcts and the full extent of a brainstem ischaemia[3].