Texture analysis in susceptibility-weighted imaging may be useful to differentiate acute from chronic multiple sclerosis lesions.

OBJECTIVES: To evaluate the diagnostic performance of texture analysis (TA) applied on non-contrast-enhanced susceptibility-weighted imaging (SWI) to differentiate acute (enhancing) from chronic (non-enhancing) multiple sclerosis (MS) lesions. METHODS: We analyzed 175 lesions from 58 patients with relapsing-remitting MS imaged on a 3.0 T MRI scanner and applied TA on T2-w and SWI images to extract texture features. We evaluated the presence or absence of lesion enhancement on T1-w post-contrast images and performed a computational statistical analysis to assess if there was any significant correlation between the texture features and the presence of lesion activity. ROC curves and leave-one-out cross-validation were used to evaluate the performance of individual features and multiparametric models in the identification of active lesions. RESULTS: Multiple TA features obtained from SWI images showed a significantly different distribution in acute and chronic lesions (AUC, 0.617-0.720). Multiparametric predictive models based on logistic ridge regression and partial least squares regression yielded an AUC of 0.778 and 0.808, respectively. Results from T2-w images did not show any significant predictive ability of neither individual features nor multiparametric models. CONCLUSIONS: Texture analysis on SWI sequences may be useful to differentiate acute from chronic MS lesions. The good diagnostic performance could help to reduce the need of intravenous contrast agent administration in follow-up MRI studies. KEY POINTS: • Texture analysis applied on SWI sequences may be useful to differentiate acute from chronic multiple sclerosis lesions • The good diagnostic performance could help to minimize the need of intravenous contrast agent administration in follow-up MRI studies.

Tumefactive inflammatory leukoencephalopathy in cocaine users: Report of three cases.

BACKGROUND: Cocaine is the most common illicit stimulant drug used in Europe, and it can potentially affect the central nervous system due to a direct effect, or by means of additive drugs. Levamisole has been increasingly used as an additive drug since it extends the stimulating effects of cocaine. This has led to an increase in the detection of levamisole adverse reactions, including levamisole-induced multifocal inflammatory leukoencephalopathy (MIL), a potentially lethal monophasic cerebral demyelinating disease. METHODS: We present three adult patients who developed a MIL with tumefactive demyelinating lesions, leading to encephalopathy and motor manifestations. All these patients had in common a history of chronic or acute use of cocaine. Imaging findings revealed a tumefactive MIL, following a Balo's Concentric Sclerosis (BCS) pattern in two cases. RESULTS: The pathophysiology of levamisole-induced MIL may depend on an immunological mechanism, producing multiple demyelinating lesions affecting the subcortical and periventricular white matter, basal ganglia and/or brainstem. Atypical demyelinating lesions are an unusual finding in levamisole-induced MIL. Specifically, the BCS pattern is a rare finding in these patients: to our knowledge, only two more cases mimicking BCS have been reported in the literature, which have also occurred in chronic cocaine users. CONCLUSIONS: Based on the history and images of our patients and other two similar case reports, we suggest a probable pathophysiological relationship between levamisole-adulterated cocaine use and the occurrence of MIL with atypical demyelinating lesions, even when they present following a BCS imaging pattern.