In patients with acute ischemic stroke, more distal thrombus location, greater thrombus permeability, and longer time to recanalization assessment were associated with recanalization of arterial occlusion after administration of intravenous alteplase; among patients who did not receive alteplase, rates of arterial recanalization were low. These findings may help inform treatment and triage decisions in patients with acute ischemic stroke.

Background and Purpose— Intraluminal thrombus (ILT) is an uncommon finding among patients with ischemic stroke. We report clinical-imaging manifestations, treatment offered, and outcome among patients with ischemic stroke/transient ischemic attack and ILT in their cervico-cephalic arteries. Methods— Sixty-one of 3750 consecutive patients with acute ischemic stroke/transient ischemic attack (within 24 hours of onset) and ILT on initial arch-to-vertex computed tomography angiography from April 2015 through September 2017 constituted the prospective study cohort. Functional outcome was assessed using the modified Rankin Scale score with functional independence at discharge defined as modified Rankin Scale score ≤2. Results— Prevalence of ILT on computed tomography angiography was 1.6% (95% CI, 1.2%–2.1%). Median age was 67 years (interquartile range, 56–73), and 40 subjects (65%) were male. The initial clinical presentation included transient ischemic attack in 12 (20%) and stroke in 49 patients (80%); most strokes (76%) were mild (National Institutes of Health Stroke Scale ≤5). The most common ILT location was cervical carotid or vertebral artery (n=48 [79%]) followed by intracranial (n=11 [18%]) and tandem lesions (n=2 [3%]). The most common initial treatment strategy was combination antithrombotics (heparin with single antiplatelet agent) among 57 patients (93%). Follow-up computed tomography angiography (n=59), after a median 6 days (interquartile range 4–10 days), revealed thrombus resolution in 44 patients (75% [completely in 27%]). Twenty four of 30 patients (80%) with >50% residual carotid stenosis underwent carotid revascularization (endarterectomy in 15 and stenting in 9 patients) without peri-procedural complications a median of 9 days after symptom onset. In-hospital stroke recurrence occurred in 4 patients (6.6%). Functional independence was achieved in 46 patients (75%) at discharge. Conclusions— Patients presenting with acute stroke/transient ischemic attack with ILT on baseline imaging have a favorable clinical course in hospital with low stroke recurrence, high rate of thrombus resolution, and good functional outcome when treated with combination antithrombotic therapy.

Background and Purpose: There is interest in what happens over time to the thrombus after intravenous alteplase. We study the effect of alteplase on thrombus structure and its impact on clinical outcome in patients with acute stroke. Methods: Intravenous alteplase treated stroke patients with intracranial internal carotid artery or middle cerebral artery occlusion identified on baseline computed tomography angiography and with follow-up vascular imaging (computed tomography angiography or first run of angiography before endovascular therapy) were enrolled from INTERRSeCT study (Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography). Thrombus movement after intravenous alteplase was classified into complete recanalization, thrombus migration, thrombus fragmentation, and no change. Thrombus migration was diagnosed when occlusion site moved distally and graded according to degrees of thrombus movement (grade 0–3). Thrombus fragmentation was diagnosed when a new distal occlusion in addition to the primary occlusion was identified on follow-up imaging. The association between thrombus movement and clinical outcome was also evaluated. Results: Among 427 patients in this study, thrombus movement was seen in 54% with a median time of 123 minutes from alteplase administration to follow-up imaging, and sub-classified as marked (thrombus migration grade 2–3 + complete recanalization; 27%) and mild to moderate thrombus movement (thrombus fragmentation + thrombus migration grade 0–1; 27%). In patients with proximal M1/internal carotid artery occlusion, marked thrombus movement was associated with a higher rate of good outcome (90-day modified Rankin Scale, 0–2) compared with mild to moderate movement (52% versus 27%; adjusted odds ratio, 5.64 [95% CI, 1.72–20.10]). No difference was seen in outcomes between mild to moderate thrombus movement and no change. In M1 distal/M2 occlusion, marked thrombus movement was associated with improved 90-day good outcome compared with no change (70% versus 56%; adjusted odds ratio, 2.54 [95% CI, 1.21–5.51]). Conclusions: Early thrombus movement is common after intravenous alteplase. Marked thrombus migration leads to good clinical outcomes. Thrombus dynamics over time should be further evaluated in clinical trials of acute reperfusion therapy.

The Alberta Stroke Program Early CT Score on non-contrast CT is a key component of prognostication and treatment selection in acute stroke care. Previous findings show that the reliability of this scale must be improved to maximize its clinical utility. Areas covered: This review discusses technical, patient-level, and reader-level sources of variability in ASPECTS reading; relevant concepts in the psychology of medical image perception; and potential interventions likely to improve inter- and intra-rater reliability. Expert commentary: Approaching variability in medical decision making from a psychological perspective will afford cognitively informed insights into the development of interventions and training techniques aimed at improving this issue.

Introduction: Decisions to transport patients from primary to comprehensive stroke centre would be influenced by info on likelihood/timing of spontaneous or IV tPA recanalization (recan). We examined recan rates by time for a wide range of occlusion sites in the INTERRSeCT multicenter prospective cohort study. Methods: Acute stroke patients consented/enrolled at 12 centers/5 countries if intracranial occlusion present on baseline CTA; eGFR≥60 ml/min. CTA was repeated 2-6 hrs later for recan unless patient taken for EVT (first run of angio used instead). Primary outcome was successful recan (rAOL scale score 2b/3) interpreted by central core lab. Results: 619 patients enrolled, 81.6% received IV tPA. 59.9% recan by follow-up CTA and 40.1% by first run angio. Median baseline NIHSS 14 (IQR 11); mean age 70.1 yrs (SD 13); median onset to baseline CTA 115 mins (IQR 108). Recan assessment imaging median 162 mins (IQR 198) from IV tPA bolus or baseline CTA (if no IV tPA). Successful recan (rAOL 2b-3) rates comparing baseline to repeat imaging shown in Figure 1a (IV tPA red; no IV tPA blue). IV tPA had much higher recan than non-IV tPA group (30.5% vs 11%, p<0.0001). Successful recan rates by occlusion site and by time from IV tPA bolus shown in Figure 1b. Site of occlusion, tPA administration, time from tPA to recan assessment and baseline residual flow were the only independent predictors of recan (all p<0.0001). Distal M1 MCA had highest recan [RR 4.12; 95% CI 1.91-8.86 vs. ICA]. Conclusions: Early recan rates were low across all occlusion sites. Beyond 6 hrs post tPA, recan rates approached EVT levels except for ICA. Imaging factors such as residual flow may further refine transport/triage decisions.

In this review we will discuss Non-Contrast Computed Tomography (NCCT), CT-Angiography (CTA), and CT-Perfusion (CTP) in assessment of patients with acute ischaemic stroke and intracerebral haemorrhage. Intravenous tPA was the only proven therapy for acute ischaemic stroke presenting within 4.5 hours, until the five recent trials proved the efficacy of EVT for acute ischaemic stroke with proximal arterial occlusion. Imaging played a major role in patient selection in all five trials. Expert commentary: The challenge of rapid clinical assessment, review of imaging and timely treatment will continue to be made easier as the development and understanding of imaging progresses.

Silent pulmonary embolism (PE) may be associated with acute ischemic stroke (AIS). We identified 10 patients from 3,132 unique patients (3,431 CT scans). We retrospectively examined CT angiogram of patients with AIS to determine the frequency of concurrent PE in AIS. The period prevalence of PE was 0.32. Seven patients had concurrent PE, whereas three had PE diagnosed 2 days after their AIS presentation. We suspected paradoxical embolism via patent foramen ovale as the cause of stroke in three patients and thrombophilia in four patients. Seven patients had poor outcome including four deaths. CT angiogram stroke protocol images from aortic arch to vertex allows visualization of upper pulmonary arteries and PE detection in AIS.

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