diagnosis and imaging

Wern Yew Ding, MBChB

Senadeera SC, Palmer DG, Keenan R, Beharry J, Yuh Lim J, Hurrell MA, Mouthaan P, Fink JN, Wilson D, Lim A, Wu TY. Left Atrial Appendage Thrombus Detected During Hyperacute Stroke Imaging Is Associated With Atrial Fibrillation. Stroke. 2020;51:3760–3764.

Atrial fibrillation (AF) is an established risk factor for thromboembolic events, including ischemic stroke. Therefore, identification of patients with this arrhythmia is important to facilitate the implementation of stroke prevention therapy using oral anticoagulation. Nonetheless, as a significant proportion of patients with AF remain asymptomatic, it remains largely under-diagnosed in the general population. Given that the source of emboli in the majority of AF-related strokes originates from the left atrial appendage (LAA), inclusion of this structure in imaging protocols may have a role in aiding the diagnosis of AF.

In a recent retrospective study of consecutive patients with ischemic stroke or transient ischemic attack, Senadeera and colleagues investigated the prevalence of computed tomography angiography (CTA)-detected LAA thrombus during hyperacute stroke imaging and evaluated the association between LAA thrombus and AF. The imaging protocol consisted of non-contrast CT, followed by CT perfusion and CTA from aortic arch to vertex. Two experienced physicians and pre-defined measures were used to assess for LAA thrombus on these scans.

Elena Zapata-Arriaza, MD
@ElenaZaps

Al-Dasuqi K, Payabvash S, Torres-Flores GA, Strander SM, Nguyen CK, Peshwe KU, Kodali S, Silverman A, Malhotra A, Johnson MH, et al. Effects of Collateral Status on Infarct Distribution Following Endovascular Therapy in Large Vessel Occlusion Stroke. Stroke. 2020;51:e193–e202.

Collateral status has been related to impact on infarct size after ischemic stroke (IS) recanalization. However, the smaller final infarct size is not always related to a good clinical situation, which seems to be related to the eloquence of the affected area, rather than the volume of the ischemic area itself. The present scientific work aims to evaluate the relation between collateral status and reperfusion degree on final infarct distribution and clinical outcome after IS due to large vessel occlusion (LVO).

Al-Dasuqi and colleagues performed a single center retrospective analysis of all patients with LVO who were treated with endovascular treatment between 2013-2019. The authors collected clinical, demographic and radiological data. They applied a multivariate voxel-wise general linear model to correlate the distribution of final infarction with collateral status and degree of reperfusion. Early favorable outcome was defined as a discharge modified Rankin Scale score ≤2.

Tolga D. Dittrich, MD

Goyal M, Ospel JM, Menon B, Almekhlafi M, Jayaraman M, Fiehler J, Psychogios M, Chapot R, van der Lugt A, Liu J, et al. Challenging the Ischemic Core Concept in Acute Ischemic Stroke Imaging. Stroke. 2020;51:3147–3155.

Endovascular treatment (EVT) is a fundamental component of acute therapy for ischemic stroke due to large vessel occlusion. Although the clinical decision for or against EVT is individual and multifactorial, it is mainly based on radiological parameters, especially the ischemic core’s visualization on neuroimaging. In their review, Goyal et al. address the practical difficulties in attributing image-defined core significance to EVT.

Clinically, the term “core” is commonly used as a synonym for infarcted brain tissue that can no longer be saved. However, the concept of a homogeneous infarction core is increasingly being challenged. The reality seems to be much more complicated, since the susceptibility of different cell and tissue types is variable, and, depending on the speed of reperfusion, there may be no, partial, or complete necrosis of the core area.

Melanie R. F. Greenway, MD

Di Meglio L, Desilles J-P, Solonomenjanahary M, Labreuche J, Ollivier V, Dupont S, Deschildre C, Maacha MB, Consoli A, Lapergue B, et al. DNA Content in Ischemic Stroke Thrombi Can Help Identify Cardioembolic Strokes Among Strokes of Undetermined Cause. Stroke. 2020;51:2810–2816.

With cryptogenic stroke comprising 20-30% of all ischemic stroke, many researchers are investigating a variety of methods to de-mystify cryptogenic stroke. In this article, potential biomarkers of the clot retrieved from mechanical thrombectomy were compared to the known stroke cause to evaluate potential clot characteristics that may predict stroke cause.

Glycoprotein VI (GPVI), heme, and DNA content were used to evaluate platelet, red blood cell, and leukocyte content of a random sample of 250 thrombi from 1209 consecutive acute ischemic stroke patients who underwent mechanical thrombectomy. 

The thrombus specimens were grinded through a tissue lyser, and thrombus homogenates were recovered after centrifugation. RBC content was estimated using heme concentration. GPVI levels were used to estimate platelet concentration. DNA content was quantified as an estimation of leukocyte count.

Elena Zapata-Arriaza, MD
@ElenaZaps

Esenwa C, Lee J-A, Nisar T, Shmukler A, Goldman I, Zampolin R, Hsu K, Labovitz D, Altschul D, Haramati LB. Utility of Apical Lung Assessment on Computed Tomography Angiography as a COVID-19 Screen in Acute Stroke. Stroke. 2020.

Acute ischemic stroke (AIS) management has changed since the beginning of the COVID-19 pandemic. Chart flows and assessment protocols have evolved with the aim of redirecting stroke and COVID-19 patients to places prepared for their management. The use of thorax CT has been implemented in patients with ischemic stroke, to identify patients infected with SARS-Cov-2, regardless of respiratory symptoms.

At the beginning of 2020, it was difficult for a vascular neurologist to imagine how essential it is to perform an accurate thoracic imaging test in those patients with ischemic stroke. Although these measures have improved patient management circuits, they have also led to an increase in the time to revascularization treatments with the impact that this entails. Taking advantage of the CT angiography protocols performed in stroke codes, evaluating the diagnostic accuracy of apical lung exam to identify patients with COVID-19, has been the authors’ aim.