Neuromyelitis optica: atypical clinical and neuroradiological presentation

Neuromyelitis Optica Spectrum Disorder Mimicking Pontine Stroke: A Case Report and Systematic Literature Review

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disorder that was first described in the late 1800s as a variant of multiple sclerosis (MS). However, it has recently been categorized, as a disease, especially with the discovery of aquaporin-4 (AQP4-Ab) and myelin oligodendrocyte glycoprotein antibodies (MOG-Ab). Unfortunately, patient presentation is not always clear, and NMOSD may initially be diagnosed as an alternative neurological disease. We present a 58-year-old woman who was hospitalized several times for what was initially perceived as a pontine stroke. However, given worsening symptoms, serologic testing confirmed AQP4-Ab positivity and, subsequently, the NMOSD diagnosis. In addition to the case report, a systematic literature review was performed to identify NMOSD cases initially misdiagnosed as stroke. Publications were selected and curated in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six NMOSD patients were initially thought to have had acute strokes. However, steady progression and/or the recurrence of symptoms suggested that further investigations with neuroimaging studies and serological immune assays were necessary to exclude alternative etiologies. Notably, the age at onset in all cases was significantly more advanced than patients with typical NMOSD presentations (median age 32-41). In conclusion, the NMOSD diagnosis should be considered in cases with atypical stroke-like presentations, particularly those of later onset (defined as equal to or greater than 50 years of age). This is important as early recognition and treatment with immune therapies can improve functional outcomes.

Neuromyelitis optica spectrum disorder mimicking extensive leukodystrophy

Brain MRI was originally considered to appear normal in neuromyelitis optica spectrum disorders (NMO-SD). Typical brain lesions are now well described and have been integrated in the latest revision of NMO-SD criteria, but the NMO-SD MRI pattern remains not yet comprehensive. We report here extensive white matter lesions (EWML) mimicking leukodystrophy in a 50-year-old woman with long-lasting anti-AQP4+ NMO-SD. We suggest that EWML could be a possible brain MRI presentation of NMO-SD patients.

Effects of serial macrocyclic-based contrast materials gadoterate meglumine and gadobutrol administrations on gadolinium-related dentate nuclei signal increases in unenhanced T1-weighted brain: a retrospective study in 158 multiple sclerosis (MS) patients

PURPOSE

To perform T1 signal intensity (SI) measurements in the dentate nuclei of adult patients with confirmed multiple sclerosis (MS) after serial administrations of the macrocyclic gadolinium-based contrast agents (GBCAs), gadoterate meglumine and gadobutrol.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and informed consent was waived. A review of our PACS database for the period from March 1, 2007 to July 31, 2016 revealed 158 confirmed MS patients who received exclusively either gadoterate meglumine (n = 81) or gadobutrol (n = 77) for diagnosis and follow-up. SI measurements on unenhanced T1-weighted images were performed on all scans of all patients and at regions of interest (ROIs) positioned on the dentate nucleus (DN) and pons. The dentate nucleus-to-pons (DNP) T1-SI ratio was subsequently calculated. Unpaired T test and regression analysis were used to evaluate statistical differences.

RESULTS

An increase in DNP was noted between the first and last MR examinations for both gadoterate meglumine (0.0032 ± 0.0216) and gadobutrol (0.0019 ± 0.0346). Although the differences were not statistically significant based across the entire patient population, visible T1 hyperintensity in the DN was noted in approximately one-third of all patients in each group that received at least five administrations of either GBCA.

CONCLUSIONS

SI increases on unenhanced T1-weighted images possibly indicative of gadolinium retention occur after serial administrations of the macrocyclic GBCAs, gadoterate meglumine and gadobutrol.

Is size an essential criterion to define tumefactive plaque? MR features and clinical correlation in multiple sclerosis

Tumefactive multiple sclerosis is an inflammatory demyelinating disease of the central nervous system. It has recently been described as a rare subtype of multiple sclerosis (MS) characterised by the appearance of solitary or multiple space-occupying lesions associated with imaging characteristics mimicking neoplasm. Atypical features include plaque size >2 cm with mass effect, oedema, and/or ring enhancement on magnetic resonance (MR) images.This study is a retrospective review designed to evaluate the prevalence of tumefactive plaques in a selected population of 440 MS patients referred to our MS centre in Southern Italy between 2005 and 2014. We analysed the radiographic features of lesions ranging in size from 0.5 to 2 cm to establish whether smaller plaques with MR characteristics similar to tumefactive plaques present different symptoms, disease evolution and prognosis. We also aimed to ascertain if MR features suggestive of biological aggressiveness could be useful prognostic criteria for a correct diagnosis of the disease and subsequent treatment. Our data suggest that lesions 0.5-2 cm and >2 cm have similar MR features and clinical evolution.

Vascular malformation mimicking multiple sclerosis active plaque: Usefulness of susceptibility weighted imaging (SWI) to perform correct diagnosis

Brain focal hyperdensity areas are common findings in computed tomography examinations, often further evaluated in magnetic resonance imaging exams. These are usually haemosiderin and calcified perivascular clusters known as cerebral microbleeds and may be secondary signs of brain disorders. Cerebral microbleeds are paramagnetic and ferromagnetic substances determining magnetic field inhomogeneity. Susceptibility weighted imaging (SWI) performed at 3T with phase post-processing is very useful in evaluating this field variation. In fact in the past decade SWI has been increasingly reported for its clinical value in adults with neurologic disorders, traumas, arterial venous malformations, occult venous diseases, tumours and functional brain imaging. The occasional computed tomography findings of single or multiple focal hyperdense areas can mimic many of these brain disorders and lead to misinterpretations. For these reason it is useful to have a more detailed diagnosis with MRI brain examination. The authors highlight the role of SWI sequence in the differential diagnosis among active plaque, vascular malformation and haemorrhagic lesion in a case report of a 41-year-old woman suffering from multiple sclerosis with a focal hyperdense area reported in a computed tomography brain examination.