Spectrum of MRI findings of progressive multifocal leukoencephalopathy in patients with multiple sclerosis in the Czech Republic
Abstract
Aim: To show the full spectrum of MRI findings in all patients ever diagnosed with progres sive multifocal leukoencephalopathy (PML), which is as sociated with natalizumab therapy in patients with MS in the Czech Republic. Patients and methods: The first case was described in 2009, the last case in December 2018, with a total of 14 diagnosed cases of PML in MS patients.
This paper evaluates the MRI findings that showed the presence of PML; the diagnosis was subsequently confirmed by detection of the John Cun ningham virus (JCV) DNA from cerebrospinal fluid using polymerase chain reaction. All patients met the American Academy of Neurology criteria from 2013 for diagnosis of this dis ease.
The MRI protocol used was variable, both because patients were examined at different MRI sites across the Czech Republic, and because of evolution of protocols over time. In all patients, the protocol contained fluid attenuated inversion recovery (FLAIR), which is the most sensitive sequence for early PML detection.
Results: 13 patients (92.9%) had a positive MRI finding. The most frequent fi nd ing was typical white matter involvement in the subcortical area of the frontal lobe (42.9%), fol lowed by the parietal (28.6%) and temporal lobes (28.6%).
The extent of the pathology was also very variable, from very small discrete lesions to extensive diffuse lesions affect ing multiple lobes. Two patients were found to have cerebel lar and pons foci (14.3%), one patient in the mesencephalon and another in the medula oblongata.
There were thalamic lesions in two cases, and one case of putamen lesions. In some cases, MRI presentation of PML was very similar to the MRI presentation of MS and suspicion of PML was considered because there was new progression of MRI.
One patient was completely atypical compared to the rest of the group. PML was diagnosed from a routine lumbar puncture done when therapy was changed, and the MRI finding at that time was negative.
Positive findings appeared only 6 months after the PML dia gnosis. This case involved the JCV-granulocytic neuronopathy with cerebel lum affection subtype.
Conclusion: The Czech cohort of PML patients confirms the great variability in MRI f ndings and points out the importance of careful MRI monitoring to detect the disease in the subclinical phase.