Overview of MRI findings in progressive multifocal leukoencephalopathy
Koichiro Mori1, Mariko Kurokawa2, Masafumi Harada3
1Department of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-Ku, Tokyo, 113-8677, Japan. momosan0929@gmail.com.
Japanese Journal of Radiology
|July 21, 2025
Summary
Progressive multifocal leukoencephalopathy (PML) is a severe brain disease caused by JC virus (JCV). Early MRI detection, especially using T2WI and SWI, improves outcomes for high-risk patients.
Area of Science:
- Neurology
- Radiology
- Infectious Diseases
Background:
- Progressive multifocal leukoencephalopathy (PML) is a serious central nervous system demyelinating disease caused by JC virus (JCV) infection.
- PML affects immunocompromised individuals, including those with HIV/AIDS, hematological malignancies, organ transplants, autoimmune diseases, or multiple sclerosis on disease-modifying therapies.
Purpose of the Study:
- To provide a comprehensive overview of PML's imaging characteristics on MRI.
- To emphasize early diagnostic MRI features for improved patient outcomes.
- To detail PML's imaging across various stages and clinical subtypes.
Main Methods:
- Review of MRI findings across multiple sequences: T2WI/FLAIR, T1WI, DWI, and SWI.
- Identification of characteristic early-stage imaging patterns like the "punctate pattern" and "milky way appearance."
- Discussion of diagnostic challenges, including low JCV DNA levels in CSF and the need for ultrasensitive PCR.
Main Results:
- PML lesions typically show T2WI/FLAIR hyperintensity, T1WI hypointensity, and DWI hyperintensity.
- Susceptibility-weighted imaging (SWI) hypointensity is emerging as a potential early diagnostic marker.
- Early detection significantly improves survival rates, with mortality ranging from 20-90%.
Conclusions:
- MRI is crucial for diagnosing PML, with characteristic findings on various sequences.
- Recognizing early MRI markers, such as the punctate pattern and SWI hypointensity, is vital for timely intervention.
- Regular MRI screening in high-risk populations is essential for improving patient prognosis and survival.
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