Punctate pattern: A promising imaging marker for the diagnosis of natalizumab-associated PML

Objective:

To evaluate the usefulness of the punctate pattern (PP) for the diagnosis and follow-up of patients with progressive multifocal leukoencephalopathy (PML).

Methods:

A cohort of 20 consecutive patients with PML, related to natalizumab (NTZ) (n = 14) or not (n = 6), underwent 3T MRI (147 MRI examinations). MRI was available at presymptomatic (n = 9 patients), symptomatic (n = 15), immune reconstitution inflammatory syndrome (IRIS), and chronic stages (n = 20). A pathologic control group of patients without PML (n = 80), with clinically definitive multiple sclerosis or a clinically isolated syndrome suggestive of CNS demyelination, underwent the same MRI protocol. Number and appearance of punctate lesions were assessed by 3 blinded readers using T2-weighted, fluid-attenuated inversion recovery (FLAIR), and postcontrast T1-weighted images.

Results:

Interobserver agreement was good ( = 0.79) (0.72–0.87). Of the 20 patients with PML, 18 had PP, including the 14 patients with NTZ-PML; none in the pathologic control group. Of the 9 presymptomatic patients with NTZ-PML, PP was observed in 7 (78% sensitive and 100% specific). Nonenhancing PP on T2-weighted/FLAIR images was detected in 13 patients with PML, exclusively at the presymptomatic or symptomatic stages (including 7 NTZ-PML), whereas enhancing PP occurred in 16 patients with PML, including 13 of the 14 patients with NTZ-PML at the IRIS stage.

Conclusions:

PP is a highly specific feature of PML and may be the first imaging feature at the presymptomatic stage with potential implications in patient care.

Classification of evidence:

This study provides Class II evidence that a PP on MRI accurately identifies patients with NTZ-PML.

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from #Med Blogs by Alexandros G.Sfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/1pcchld
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