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MRI pattern in asymptomatic natalizumab-associated PML
Mike P Wattjes1, Anke Vennegoor2, Martijn D Steenwijk1
1Department of Radiology and Nuclear Medicine, MS Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
Objective:
To investigate the MRI manifestation pattern of asymptomatic natalizumab-associated progressive multifocal leukoencephalopathy (PML) in patients with multiple sclerosis (MS).
Methods:
18 patients with MS with natalizumab-associated PML lesions on MRI were included. In 6 patients, the PML lesions were identified on MRI prospectively and in 12 patients PML lesions were identified retrospectively. MRI sequences were analysed for PML lesion distribution, appearance, grey matter/white matter involvement and possible signs of inflammation. Lesion probability maps were created to demonstrate lesion distribution pattern.
Results:
The frontal lobe was involved in 14 patients (77.8%) and the parietal lobe in 4 patients (22.2%). Most patients presented with focal lesions (13 patients, 72.2%) involving one single lobe (12 patients, 66.7%). The cortical grey matter was affected in 15 patients (83.3%) and 13 patients (72.2%) presented with a combination of cortical grey and white matter involvement. Signs of inflammation were detected in 7 patients (38.8%). Among patients with available diffusion-weighted imaging, 6 patients (40%) did not show high-signal-intensity lesions. A classical imaging pattern including unilateral and unilobar focal lesions in the frontal lobe affecting the cortical grey matter or the cortical grey and adjacent white matter was observed in 8 patients (44.4%).
Conclusions:
Asymptomatic natalizumab-associated PML manifestations on MRI show a rather localised disease, frequently located in the frontal lobes, affecting the cortical grey matter and adjacent juxtacortical white matter. Awareness of this lesion pattern facilitates an earlier diagnosis of natalizumab-associated PML in an asymptomatic stage associated with a more favourable prognosis.
Insights
Early MRI signs of progressive multifocal leukoencephalopathy (PML) in multiple sclerosis patients treated with natalizumab often appear localized. These asymptomatic PML lesions frequently affect the frontal lobe
Area of Science:
- Neurology
- Radiology
- Immunology
Background:
- Natalizumab is a treatment for multiple sclerosis (MS).
- Progressive multifocal leukoencephalopathy (PML) is a rare but serious side effect of natalizumab treatment.
- Detecting PML in its early, asymptomatic stage is crucial for patient outcomes.
Purpose of the Study:
- To define the MRI characteristics of asymptomatic natalizumab-associated PML in MS patients.
- To identify patterns that aid in early diagnosis.
Main Methods:
- Retrospective and prospective analysis of MRI scans from 18 MS patients with natalizumab-associated PML.
- Evaluation of lesion distribution, grey/white matter involvement, and signs of inflammation.
- Creation of lesion probability maps to visualize distribution patterns.
Main Results:
- Frontal lobe involvement was observed in 77.8% of patients.
- Lesions were often focal and unilateral, frequently affecting cortical grey matter (83.3%).
- A classical pattern of unilateral, unilobar frontal lesions involving cortical grey matter was seen in 44.4%.
Conclusions:
- Asymptomatic natalizumab-associated PML on MRI typically presents as localized lesions, predominantly in the frontal lobes.
- These lesions often affect the cortical grey matter and adjacent white matter.
- Recognizing this pattern can lead to earlier diagnosis and potentially better prognoses.
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