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Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Progressive multifocal leukoencephalopathy: value of diffusion-weighted and contrast-enhanced magnetic resonance
1Department of Neuroradiology, Medical School, University of Tübingen, Tübingen, Germany. wilhelm.kueker@orh.nhs.uk.
Abstract:
Progressive multifocal leukoencephalopathy (PML) is caused by the replication of JC virus in oligodendrocytes of immunocompromised patients. Diagnosis usually relies on the polymerase chain reaction (PCR)-based demonstration of JC virus DNA in the cerebrospinal fluid. As previous reports have suggested that some patients may benefit from antiviral therapy, non-invasive early diagnosis is highly desirable. Repetitive magnetic resonance imaging (MRI) examinations (two to nine) were obtained in seven patients (aged 40-67 years, six males, one female) with classical clinical and imaging findings of PML. Five patients had underlying hematological disorders and two acquired immune deficiency syndrome. PCR of the cerebrospinal fluid (CSF) specimen was positive for JC virus DNA in six patients. MRI sequences included T2-, T1- and diffusion-weighted (DW) images in all patients and diffusion-tensor imaging (DTI) in four cases. DTI was once performed at 3T, in the remaining patients at 1.5T. All patients received antiviral treatment with cidofovir in addition to the treatment of the underlying disorder. MRI showed areas of T2 hyperintensity with involvement of the subcortical U-fibers and restricted diffusion in all patients. Areas of diffusion abnormality correlated with disease progress. Contrast enhancement was encountered once after successful treatment and heralded clinical remission with virus elimination from the CSF. Hence, MRI including DW and contrast-enhanced images may be used to evaluate disease activity. Contrast enhancement may indicate an inflammatory response and thus herald immunologic virus elimination.
Insights
Magnetic resonance imaging (MRI) can help diagnose progressive multifocal leukoencephalopathy (PML) by showing characteristic brain changes. Contrast enhancement on MRI may indicate an inflammatory response and successful treatment of JC virus infection.
Area of Science:
- Neuroimaging
- Infectious Diseases
- Neurology
Background:
- Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease caused by JC virus replication in immunocompromised individuals.
- Current diagnosis often relies on JC virus DNA detection in cerebrospinal fluid (CSF) via polymerase chain reaction (PCR).
- Early and non-invasive diagnostic methods are crucial, especially given potential benefits from antiviral therapies.
Purpose of the Study:
- To evaluate the utility of serial magnetic resonance imaging (MRI), including diffusion-weighted (DW) and diffusion-tensor imaging (DTI), in diagnosing and monitoring PML.
- To assess the role of contrast enhancement in MRI for indicating disease activity and treatment response.
Main Methods:
- Seven patients with clinical and imaging findings suggestive of PML underwent serial MRI examinations (2-9 scans per patient).
- MRI sequences included T2, T1, DW imaging, and DTI (at 1.5T or 3T).
- All patients received antiviral treatment with cidofovir alongside management of their underlying condition.
Main Results:
- All patients exhibited T2 hyperintensities involving subcortical U-fibers and restricted diffusion on DW imaging, correlating with disease progression.
- JC virus DNA was detected in CSF via PCR in six of the seven patients.
- One patient showed contrast enhancement after successful treatment, preceding clinical remission and CSF viral clearance.
Conclusions:
- Serial MRI, particularly DW and contrast-enhanced imaging, can effectively evaluate PML disease activity.
- Contrast enhancement may signify an inflammatory response, potentially heralding successful immunologic clearance of JC virus.
