Carotid atherosclerosis is a major cause for stroke, with significant associated disease burden morbidity and mortality in Western societies. Diagnosis, grading and follow-up of carotid atherosclerotic disease relies on imaging, specifically ultrasound (US) as the initial modality of choice. Traditionally, the degree of carotid lumen stenosis was considered the sole risk factor to predict brain ischemia. However, modern research has shown that a variety of other imaging biomarkers, such as plaque echogenicity, surface morphology, intraplaque neovascularization and vasa vasorum contribute to the risk for rupture of carotid atheromas with subsequent cerebrovascular events. Furthermore, the majority of embolic strokes of undetermined origin are probably arteriogenic and are associated with nonstenosing atheromas. Therefore, a state-of-the-art US scan of the carotid arteries should take advantage of recent technical developments and should provide detailed information about potential thrombogenic (/) and emboligenic arterial wall features. This manuscript reviews recent advances in ultrasonographic assessment of vulnerable carotid atherosclerotic plaques and highlights the fields of future development in multiparametric arterial wall imaging, in an attempt to convey the most important take-home messages for clinicians performing carotid ultrasound.

Background and Purpose: Differentiation between glioblastoma multiforme (GBM) and solitary brain metastasis (SBM) remains a challenge in neuroradiology with up to 40% of the cases to be incorrectly classified using only conventional MRI. The inclusion of perfusion MRI parameters provides characteristic features that could support the distinction of these pathological entities. On these grounds, we aim to use a perfusion gradient in the peritumoral edema.Methods: Twenty-four patients with GBM or an SBM underwent conventional and perfusion MR imaging sequences before tumors' surgical resection. After postprocessing of the images, quantification of dynamic susceptibility contrast (DSC) perfusion parameters was made. Three concentric areas around the tumor were defined in each case. The monocompartimental and pharmacokinetics parameters of perfusion MRI were analyzed in both series.Results: DSC perfusion MRI models can provide useful information for the differentiation between GBM and SBM. It can be observed that most of the perfusion MR parameters (relative cerebral blood volume, relative cerebral blood flow, relative Ktrans, and relative volume fraction of the interstitial space) clearly show higher gradient for GBM than SBM.GBM also demonstrates higher heterogeneity in the peritumoral edema and most of the perfusion parameters demonstrate higher gradients in the area closest to the enhancing tumor. Conclusion:Our results show that there is a difference in the perfusion parameters of the edema between GBM and SBM demonstrating a vascularization gradient. This could help not only for the diagnosis, but also for planning surgical or radiotherapy treatments delineating the real extension of the tumor.

Recent literature has shown that various carotid plaque features, other than stenosis, contribute to plaque vulnerability. Features such as surface morphology and plaque composition with distinct components (e.g. intraplaque hemorrhage, lipid core) have been associated with the increased risk of future cerebrovascular events. Ultrasonography constitutes the first line modality for the assessment of carotid disease and has traditionally been used to grade stenosis with high accuracy. Recenttechnological advances such as contrast-enhanced ultrasound and elastography increased the diagnostic yield of ultrasound in assessing the morphology of carotid plaques. The purpose of this review is to present the available literature on ultrasound elastography of the atherosclerotic carotid. Strain and shear wave elastography allow for the characterization of plaque components, thus indicating its nature and importantly, the plaque’s vulnerability. Shear wave elastography indices appear morerobust than Strain indices. Overall, elastography is a feasible method to distinguish vulnerable carotid plaques. There is, however, a need for larger and longer prospective controlled clinical studies in order to validate elastography as an imaging modality used for the detection of unstable carotid plaques.

We report the case of a 70-year-old woman who presented with an acute ischemic stroke involving the left frontal operculum secondary to an M2 dissection and a concomitant completely thrombosed aneurysm of the left distal middle cerebral artery. Initial imaging work-up was inconclusive due to the lack of typical radiographic features and only repeated imaging studies pointed towards the presence of an arterial dissection combined with a completely thrombosed aneurysm. The aneurysm was partially clipped and wrapped with excellent clinical result at 1-year follow-up. The clinical, imaging and therapeutic challenges of this rare entity are discussed.