Short communicationLow signal intensity in U-fiber identified by susceptibility-weighted imaging in two cases of progressive multifocal leukoencephalopathy
Introduction
Progressive multifocal leukoencephalopathy (PML), a progressive demyelinating disease of the brain caused by oligodendrocyte, astrocyte, and neuron damage resulting from reactivation of JC virus (JCV) [1], was once regarded as a fatal disease characterized by progressive neurological deficits, leading to death within 2.5–4 months of diagnosis in the absence of treatment [2]. Recently however, reports have described that in certain clinical conditions such as natalizumab therapy in multiple sclerosis patients, an early PML diagnosis, preferably in a presymptomatic/asymptomatic stage, but even in a symptomatic stage, is associated with a favorable prognosis [3], [4]. The diagnosis of PML is based on clinical information and detection of JCV in cerebrospinal fluid (CSF) or brain tissue, but a combination of specific findings from magnetic resonance imaging (MRI) enables us to suspect PML, including multifocal white matter lesions involving U-fibers, faint or absent peripheral enhancement of lesions, minimal or no mass effect, and hyperintensity on the periphery of lesions on diffusion-weighted imaging (DWI) [5], [6]. Regarding the diagnosis of PML, the official American Academy of Neurology (AAN) criteria on PML diagnosis were proposed recently based on a combination of data related to clinical features, imaging findings, and CSF polymerase chain reaction (PCR) JCV [7]. For PML diagnosis, MRI is therefore regarded as an important tool. To date, no report has described specific findings for PML obtained using susceptibility-weighted imaging (SWI). This report is the first of a potential new finding by SWI in two patients with PML.
Section snippets
Case 1
A 56-year-old man treated for repeated erysipelas and otitis externa was hospitalized with left paresis. Neurological examination showed left unilateral spatial neglect. Initial brain MRI revealed a hyperintense lesion on DWI in the subcortical lesion of the right occipital lobe. The initial diagnosis was acute brain infarction. He was treated with aspirin and edaravone for 2 weeks. He subsequently experienced repeated infection, such as that of Pneumocystis carinii pneumonia. The left paresis
MRI findings in the two PML cases
These two patients with PML underwent serial MR examinations with 3.0-T MRI (Achieva; Philips Health Care, Best, The Netherlands), including T1-weighted imaging, T2-weighted imaging, 3D FLAIR, DWI, and SWI. MRI sequences other than SWI showed typical findings for PML, such as hypointense lesions on T1-weighted imaging, hyperintense lesions on T2-weighted imaging and 3D FLAIR in subcortical white matter, and peripheral hyperintensity on DWI (Fig. 1, Fig. 2, Fig. 3). Neither a mass effect nor
Discussion
Brain MRI has been regarded as an important tool for PML diagnosis and monitoring [5], [6], [8]. Several MRI findings suggesting PML have been reported, including an asymmetrical lesion located predominantly in the subcortical white matter involving U-fibers, faint or absent peripheral enhancement, minimal or no mass effect considering lesion size, and hyperintensity on DWI at the edge of lesions correlated with active infection [5], [6]. Nevertheless, no report in the English-language
Conflict of interest
No author declares a potential conflict of interest.
References (16)
- et al.
Imaging manifestations of progressive multifocal leukoencephalopathy
Clin Radiol
(2010) - et al.
Progressive multifocal leukoencephalopathy: why gray and white matter
Annu Rev Pathol Mech Dis
(2013) - et al.
Progressive multifocal leukoencephalopathy in AIDS: are there any MR findings useful to patient management and predictive of patient survival?
AJNR Am J Neuroradiol
(1999) - et al.
Survival and functional outcome in asymptomatic natalizumab-associated progressive multifocal leukoencephalopathy multiple sclerosis patients [abstract]
Mult Scler
(2013) - et al.
Indolent course of progressive multifocal leukoencephalopathy during natalizumab treatment in MS
Neurology
(2011) - et al.
Progressive multifocal leukoencephalopathy: a review of the neuroimaging features and differential diagnosis
Eur J Neurol
(2012) - et al.
PML diagnostic criteria: consensus statement from the AAN Neuroinfectious Disease Section
Neurology
(2013) - et al.
JC virus infection of the brain
AJNR Am J Neuroradiol
(2010)
Cited by (29)
Distinct subdivisions of subcortical U-fiber regions in the gyrencephalic ferret brain
2024, Neuroscience ResearchProgressive Multifocal Leukoencephalopathy
2018, Neurologic ClinicsCitation Excerpt :Given PML predilection for subcortical white matter, lesions frequently have a scalloped appearance toward the cortex and a more poorly defined appearance toward the white matter. On susceptibility-weighted sequences, hypointense rims that involve U fibers can occur.15 In time, as the infection progresses, multifocal lesions may coalesce into large diffuse areas of signal abnormality.
Low-signal-intensity rim on susceptibility-weighted imaging is not a specific finding to progressive multifocal leukoencephalopathy
2016, Journal of the Neurological SciencesCitation Excerpt :Recently, it was reported that 61.2% of PML cases had HCS adjacent to subcortical PML lesions [9]. In one of the two PML cases described in our previous report [4], HCS was present adjacent to PML lesions, and the LSI rim was observed adjacent to HCS. Consequently, the LSI rim appears to be associated with HCS, regardless of the spectrum of diseases.
Use of quantitative susceptibility mapping (QSM) in progressive multifocal leukoencephalopathy
2016, Journal of NeuroradiologyCitation Excerpt :A typical active PML lesion shows a central core with a low signal on DWI, high signal on apparent diffusion coefficient (ADC) map and high signal on DWI consistent with restricted diffusion on the periphery [8]. SWI low signal intensities in U-fibers adjacent to the white matter lesions of PML had been recently described in two patients with PML [5]. Our study suggests a high prevalence of SWI low signal intensities in U-fibers and/or in the cortex adjacent to the white matter lesions of PML, independently of the nature of the immunosuppression: indeed all of our four patients had cortical and/or subcortical abnormalities on SWI.
OFSEP, a nationwide cohort of people with multiple sclerosis: Consensus minimal MRI protocol
2015, Journal of Neuroradiology