Learning objectives
To describe and illustrate the clinical presentations and imaging findings of the main syndromes associated with brainstem infarcts.
Correlation of clinical presentations with specific brainstem structures will facilitate greater understanding of the anatomy and functionality of the brainstem.
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 tothe 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...
Findings and procedure details
THE MIDBRAIN
Anatomy
Figure 1 illustrates the anatomical structure of the midbrain on 3T T2 weighted MR imaging and through simplified pictorial representation. The corticospinal tracts,
descending white matter pathways involved in voluntary discrete movements,
lie anteriolaterally in the upper midbrain.
Within the more caudal midbrain the corticospinal tracts move medially along the ventral surface of the cerebral peduncles. The red nuclei and medial lemniscus are located medially,
whilst the medial longitudinal fasciculus lies within the paramedian midbrain[5].
The red nuclei receive afferent fibres from...
Conclusion
Brainstem infarcts are associated with classic clinical presentations,
which should raise suspicion prior to imaging.
MR with diffusion weighted imaging is essential to identify small restriction deficits.
Increased awareness of these syndromes among radiologists performing acute CT and MR imaging will enable optimal imaging,
reduce inappropriate dismissal of subtle T2 signal change within the brainstem,
and focus attention on the diagnostic importance of diffusion weighted imaging in the brainstem.
The classification of named brainstem infarction syndromes is based on symptomatology rather than imaging findings.
There...
References
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