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Idiopathic inflammatory demyelinating lesions (IIDL) of the brain usually present with a morphologic pattern characteristic of multiple sclerosis (MS). Atypical appearances of IIDLs also exist, however, and can pose significant diagnostic problems and uncertainty regarding prognosis and adequate therapy. We attempted to improve upon this situation by reviewing the literature. We performed a PubMed search from January 1984 through December 2004 for articles in English reporting on IIDLs which had been considered as morphologically atypical (66 articles; 270 cases reported). From these publications 69 individual patient reports allowed the extraction of adequate information on magnetic resonance imaging (MRI) and associated disease characteristics. Reported atypical IIDLs most frequently manifested as large ring-like lesions (n = 27) which are now considered quite suggestive of an antibodymediated form of MS. Truly atypical IIDLs were less common and exhibited appearances which we termed megacystic (n = 8), Balolike (n = 11) and diffusely infiltrating (n = 11). Despite limitations imposed by the absence of original data the inter-rater agreement in defining these subtypes of atypical IIDLs was moderate to substantial (kappa 0.48–0.68) and we noted trends for their association with certain demographic, clinical and paraclinical variables. We suggest that IIDLs reported as atypical in the literature can be segregated into several distinct subtypes based on their MRI appearance. The recognition of these patterns may be useful for the differential diagnosis and for a future classification. Because of the limitations inherent in our review this will have to be confirmed by a prospective registry. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) plaques and age related white matter lesions (WML) are of similar morphological appearance on T2 weighted MRI. Therefore their differentiation is sometimes crucial. Proton magnetic resonance spectroscopy (1H–MRS) adds metabolic information to conventional imaging and may help to distinguish inflammatory MS plaques from vascular related WML. This study was performed to evaluate the metabolite pattern in MS plaques and WML. 15 MS patients, 14 elderly individuals with WML and 16 controls were investigated by conventional MRI and short echo quantitative 1H–MRS (TE: 30ms, TR: 3000ms). The mean metabolite concentrations in normal control white matter (NCWM), MS plaques and WML were: t–NAA: 8.96 mmol/l (SD:0.93) vs 6.79 mmol/l (SD: 1.99) vs 7.18 mmol/l (SD: 1.41); Cho: 1.66 mmol/l (SD: 0.4) vs 1.49 mmol/l (SD: 0.45) vs 1.46 mmol/l (SD: 0.34); PCr: 5.64 mmol/l (SD: 0.83) vs 4.9mmol/l (SD: 1.3) vs 4.95 mmol/l (SD: 0.86); myo– Ins: 4.57 mmol/l (SD:1.05) vs 6.34 mmol/l (SD: 2.03) vs 4.5 mmol/l (SD: 0.96). t–NAA reduction in MS plaques and WML was significant compared with controls (p ≤ 0.001). MS plaques showed significantly elevated myo– Ins concentrations compared with controls (p = 0.002) and to WML (p = 0.003). In summary MS plaques and WML show a decrease in their t–NAA concentrations compared with controls. Elevated concentrations of myo–Ins in MS plaques but not in WML makes this metabolite of special interest for their differentiation. [ABSTRACT FROM AUTHOR]

Dear Sirs, As of June 15th 2021, the COVID-19 pandemic, caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in more than 177 million confirmed cases worldwide and more than 3.8 million deaths [[1]]. Initial brain magnetic resonance imaging (MRI) revealed three T2 hyperintense lesions with a diameter of approximately around 2.5 cm in the left frontoparietal periventricular white matter. The lesions were also hyperintense on diffusion-weighted imaging with ADC restriction, and the most dorsal lesion demonstrated gadolinium ring enhancement (Fig. [Extracted from the article]