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.

Utilidad de la ecografía Doppler color en el seguimiento de la angioplastia carotídea / Doppler in Carotid Stent Follow-up

Los ataques cerebrovasculares (ACV), representan un problema mayor en salud y son una causa importante de discapacidad en todo el mundo. La estenosis u oclusión carotídea aterosclerótica causa alrededor del 20% de las isquemias cerebrovasculares.¹ Los ACV en los enfermos con estenosis carotídea se producen, en la mayoría de los casos, por la aparición de embolismos distales de trombo formado en la placa, oclusión trombótica aguda debido a rotura de la placa, o bien secundarios a las alteraciones hemodinámicas atribuibles a la estenosis, la cual produce disminución de la perfusión cerebral por el hipoflujo, en casos de estenosis críticas o suboclusivas. El tratamiento de la patología carotídea ha evolucionado de forma considerable a lo largo de los últimos años. Existen dos tratamientos invasivos para la estenosis carotídea significativa, que consisten en el abordaje quirúrgico con endarterectomía o tratamiento por vía percutánea con angioplastia y colocación de stent. En nuestra institución se realizaron, en el periodo comprendido entre marzo de 2013 y junio de 2017, aproximadamente 100 angioplastias carotídeas con colocación de stent. Todas fueron valoradas con ecografía Doppler color (EDC) al mes, a los seis meses y al año (en casos no complicados). En esta revisión bibliográfica es nuestra intención desarrollar las indicaciones, aplicaciones, hallazgos normales y patológicos en el examen de EDC en la evaluación de un paciente con stent carotídeo.

Acute stroke represents a major problem in health and is a major cause of disability worldwide. Atherosclerotic carotid stenosis or occlusion causes around 20% of cerebrovascular ischemias.¹ Stroke in patients with carotid stenosis occurs, in most cases, due to embolisms of thrombus formed in the plaque, acute thrombotic occlusion due to rupture of the plaque, or secondary to hemodynamic alterations, attributable to stenosis, which produces decreased cerebral perfusion by low flow, in cases of critical or sub occlusive stenosis. The treatment of carotid disease has evolved considerably over recent years. There are two invasive treatments for significant carotid stenosis, which consist of the surgical approach with endarterectomy or percutaneous treatment with angioplasty and stenting. In our institution, in the period between March 2013 and June 2017, ~100 carotid angioplasties with stent placement were performed. All were assessed with color Doppler ultrasound (DUS) at month, six months and one year (in non complicated cases). In this literature review it is our intention to develop the indications, applications, normal and pathological findings in the DUS examination in the evaluation of a patient with carotid stent.