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Updated: Apr 14, 2026
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
MRI characteristics of periaqueductal lesions in multiple sclerosis
Athina Papadopoulou1, Yvonne Naegelin2, Katrin Weier2
1Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland; Medical Image Analysis Center, Schanzenstrasse 55, CH-4056 Basel, Switzerland.
Background:
In multiple sclerosis (MS), periaqueductal lesions (PAL) have been described histopathologically.
Objectives:
We sought to investigate the frequency and characteristics of PAL on magnetic resonance images (MRIs) in patients with MS or clinically isolated syndrome (CIS).
Methods:
We analyzed proton density (PD)-weighted MRIs of 247 MS and 10 CIS patients. PAL were identified based on their abnormal hyperintensity and lesion shape on at least two consecutive slices. Patients with and without PAL were compared for clinical characteristics in a propensity score weighted analysis.
Results:
We identified PAL in 48/257 patients (18.7%), 34 of which had CIS or relapsing-remitting MS and 14 a progressive disease course. The shape of PAL was often circular (65%), or/and wedge-like (42%). Multi-planar image analysis in a subgroup of patients with double inversion recovery sequences revealed that 36% of PAL were periventricular lesions of the third ventricle extending towards the aqueduct. We found an association of PAL and brainstem functional system.
Conclusions:
Although PAL may be underreported in MS, they are relatively frequent and found at all clinical stages and in CIS. They could be considered as a variant of periventricular lesions in the supratentorial midbrain and thus be useful in the diagnosis of MS.
Insights
Periaqueductal lesions (PAL) are common in multiple sclerosis (MS) and clinically isolated syndrome (CIS), appearing on MRI scans. These lesions may aid in diagnosing MS, particularly when considered a variant of periventricular lesions.
Area of Science:
- Neurology
- Radiology
- Neuroimaging
Background:
- Periaqueductal lesions (PAL) are known histopathological findings in multiple sclerosis (MS).
- The frequency and imaging characteristics of PAL in MS and clinically isolated syndrome (CIS) require further investigation.
Purpose of the Study:
- To determine the frequency and characteristics of periaqueductal lesions (PAL) on magnetic resonance imaging (MRI) in patients with MS or CIS.
- To explore the association between PAL and clinical characteristics in these patient cohorts.
Main Methods:
- Analysis of proton density (PD)-weighted MRI scans from 247 MS and 10 CIS patients.
- Identification of PAL based on hyperintensity and shape across consecutive slices.
- Propensity score weighted analysis to compare clinical characteristics between patients with and without PAL.
Main Results:
- Periaqueductal lesions (PAL) were identified in 18.7% of patients (48/257).
- PAL were observed in patients with CIS, relapsing-remitting MS, and progressive MS.
- Circular and wedge-like shapes were common; 36% of PAL were periventricular lesions extending from the third ventricle towards the aqueduct.
- An association was found between PAL and the brainstem functional system.
Conclusions:
- Periaqueductal lesions (PAL) are relatively frequent in multiple sclerosis (MS) and clinically isolated syndrome (CIS), occurring across all disease stages.
- PAL may be underreported but could be considered a variant of periventricular lesions in the midbrain.
- Identification of PAL on MRI may assist in the diagnosis of MS.
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