Acute ischemic infarct identification on noncontrast computed tomography (NCCT) is highly variable between raters. A semiautomated method for segmentation of acute ischemic lesions on NCCT may improve interrater reliability.
Introduction: The prevalence of Mismatch (MM) profiles on admission perfusion imaging in large core ischemic strokes, stratified by time since last known normal (LKN) and MM profile definition, is not well described. Methods: We used a retrospective multicenter study of patients with anterior circulation large vessel occlusion, baseline MR or CT perfusion (MRP, CTP), and definitive LKN within 24 hours. We studied four MM profile definitions: 1) Mismatch ratio (MR)≥1.2, penumbral volume (Pen)≥10ml, and (if CTP) core volume defined by CBF<30%; 2) MR≥1.8, Pen≥15ml, CBF<30%; 3) MR≥1.2, Pen≥10ml, CBF<38%; 4) MR≥1.8, Pen≥15ml, CBF<38%. Two definitions of large core were evaluated (≥50ml or ≥70ml; defined as CBF<30% or CBF<38% on CTP and as ADC ≤620x10 -6 mm 2 /s on MRP). We used the Cochran-Armitage Trend Test to evaluate for trends in MM presence over time and McNemar Test to compare MM profiles for differences in prevalence. Results: Of 2012 patients included, 49% were male, median age was 75 (IQR 64-84), median baseline NIHSS was 15 (8-20), median time from LKN to imaging was 5.7 hours (1.8-8), 44% had CTP. In patients with cores ≥50ml and ≥70ml (Figures 1&2), MM profile defined by MR≥1.2 and Pen≥10ml was more prevalent than MM defined by MR≥1.8 and Pen≥15ml (P<0.001). MM prevalence decreased over time in three of four MM profiles in the ≥50ml core group but only one MM profile in the ≥70ml group (P<0.001 in all comparisons). In all core sizes (Figure 3), there was a significant trend toward decreased MM prevalence over time in all four profiles (P<0.0001) and between the MR≥1.2 and Pen≥10 vs MR≥1.8 and Pen≥15 profiles (P<0.001 in all comparisons). Similar significant differences between the MR≥1.2 and Pen≥10 vs MR≥18 and Pen≥15 existed in CTP only, MRP only, and witnessed onset only subgroup analyses (P<0.001 for all). Conclusions: MM is more prevalent when defined as MR≥1.2 and Pen≥10ml than when defined as MR≥1.8 and Pen≥15ml, especially in large cores. MM prevalence decreases over time in all core sizes, though trends are less clear with increasing infarct size. Understanding real-world prevalence of MM in large core strokes may help contextualize results of recent trials, while clarifying the optimal definition and prevalence of MM in the large core population is of import to future prospective study design. This study is limited by potential bias in favor of higher MM presence due to one site’s patient transfer acceptances contingent on favorable CTP profiles.
Neuroimaging in Patient Selection for Thrombectomy, From the AJR Special Series on Emergency RadiologyThomas R. Geisbush, MD1, Sarah J. Snyder, BS1 and Jeremy J. Heit, MD, PhD1Audio Available | Share Claim CREDIT
Introduction: Reduced left ventricular ejection fraction (EF) is associated with worse outcomes after stroke. CT perfusion (CTP) is widely used in acute stroke evaluation; its reliability in patients with reduced EF is unknown. We hypothesized that patients with reduced EF would have abnormal dose-time curves that may impair standard perfusion maps and reduce their quality. Methods: A retrospective database of all patients presenting to Stanford University for large vessel occlusion (LVO) stroke between 2010-2019 was used. CTPs were post-processed using RAPID software. Concentration-time curve metrics—width of the venous output function (VOF) at half maximum amplitude and VOF peak amplitude—were assessed automatically for each case. A reader blinded to EF visually evaluated the VOF curve for evidence of truncation (yes/no) and graded the quality of the time to maximum (Tmax) map on a scale from 0 (excellent) to 3 (poor), based on the degree of “speckling” present on the map. Continuous parameters were compared using the t-test or Mann-Whitney test and dichotomous parameters with the Fisher’s exact or Chi-square test, where appropriate. Results: 160 patients with sufficient quality baseline CTP and in-hospital echocardiogram were evaluated; 34 had EF <50%. Mean age, scan time, and cumulative contrast dose did not differ; men were more prevalent in the reduced EF group (68% vs 44%; p=0.016). Compared to patients with normal EF, patients with low EF more often had truncation of the VOF (11.8% vs 0.8%; p=0.007), had a lower VOF peak amplitude (mean 245.04 HU vs 299.07; p=0.013, 95% CI for difference 11.61 to 96.45), had wider VOF at half maximum amplitude (mean 17.84 seconds vs 14.56; p<0.0001, 1.9 to 4.65), and had worse Tmax quality (median 2 (IQR 1-3) vs 1 (0-2); p=0.002). Conclusion: Patients with reduced EF have dispersion of the contrast bolus as evidenced by a VOF curve that is wider and has a lower peak. Consequently, the quality of the Tmax map in patients with low EF is reduced, which may render automated CTP results unreliable. Additional studies are needed to determine to what extent poor CTP image quality in patients with low EF affects treatment decisions.
The only effective treatment for ischemic moyamoya disease (iMMD) is cerebral revascularization by an extracranial to intracranial bypass. The preferred revascularization method remains controversial: direct versus indirect bypass. The purpose of this study was to test the hypothesis that method choice should be personalized based on angiographic, hemodynamic, and clinical characteristics to balance the risk of perioperative major stroke against treatment efficacy.
Cerebral vasospasm following subarachnoid hemorrhage (SAH) results in significant morbidity and mortality. Intra-arterial administration of calcium channel blockers or intracranial angioplasty may be performed when non-invasive medical management fails to prevent neurologic deterioration. Technical improvements in balloon catheters are expected to improve the success and safety of cerebral angioplasty.To describe our initial experience with the new Scepter XC balloon catheter in cerebral vasospasm treatment following SAH.All patients who underwent cerebral angioplasty using the Scepter XC balloon for the treatment of medically refractory cerebral vasospasm after SAH were identified. Patient demographic information, procedural details, and outcome were obtained from electronic medical records.Five consecutive patients undergoing vasospasm treatment with cerebral angioplasty using the Scepter XC were identified. All treated patients had medically refractory vasospasm that was moderate or severe. Angioplasty of the supraclinoid internal carotid artery, the A1 and A2 segments of the anterior cerebral artery, the M1 and M2 segments of the middle cerebral artery, the V4 segment of the vertebral artery, and the basilar artery was performed. All angioplasty procedures were technically successful, and the degree of vasospasm improved significantly following angioplasty. There were no complications related to the cerebral angioplasty procedures.The Scepter XC balloon catheter is safe and effective in the treatment of cerebral vasospasm following SAH. The excellent trackability and stability of the balloon catheter and the extra compliant design of the balloon represent technical advancements in the endovascular armamentarium in the treatment of cerebral vasospasm.
Introduction Acute carotid stent occlusion (CSO) is a rare complication of endovascular carotid stent placement that requires emergent intervention. We describe angioplasty or combined angioplasty and aspiration thrombectomy as a new endovascular technique for CSO treatment. The technique is compared to others previously described in the literature. Methods We performed a retrospective cohort study of all patients who underwent endovascular treatment (ET) of acute symptomatic CSO from January 2008 to March 2018 at our neurovascular referral center. Patient demographics, endovascular treatment details, and outcome data were determined from the electronic medical record. Primary outcome was successful stent recanalization and cerebral reperfusion (modified thrombolysis in cerebral infarction (mTICI) score IIB-III). Secondary outcomes were National Institutes of Health Stroke Scale (NIHSS) shift from presentation to discharge, mortality, and modified Rankin Scale (mRS) score at 3 months. Additionally, a literature review (years 2008-2019) was performed to characterize other techniques for ET of CSO. Results Four patients who underwent ET of acute CSO were identified. ET treatment by angioplasty (n = 1) or combined aspiration thrombectomy and angioplasty (n = 3) resulted in carotid stent recanalization in all patients. Tandem intracranial occlusions were present in three patients (75%), and successful cerebral reperfusion was achieved in all patients. Patient symptoms improved (mean NIHSS shift -5.3 ± 7.2 at discharge). One patient died of a symptomatic reperfusion hemorrhage and another died of cardiac complications by 3-month follow-up. The mRS scores of the surviving patients were 1 and 3. Previously described studies (n = 14) using different and varied techniques had moderate recanalization rates and outcomes. Conclusion Combined aspiration thrombectomy and angioplasty for the neurointerventional treatment of acute CSO leads to high rates of stent recanalization and cerebral reperfusion. The recanalization rate here is improved compared to previously reported techniques. Further multicenter studies are required to risk-stratify patients for specific ET interventions.
Background: The accuracy of infarct growth prediction based on collateral scores, assessed on CT perfusion (CTP) and CT angiography, has been modest. We aimed to investigate the accuracy of infarct growth prediction using a novel collateral score based on two CTP parameters. Methods: Patients were included from CRISP2, a multi-center prospective cohort study of stroke patients with an anterior circulation large vessel occlusion who are transferred from a primary stroke center (PSC) to a comprehensive stroke center (CSC). CTP was performed at the PSC, and MRI was performed immediately after arrival at the CSC. The inter-hospital infarct growth rate was calculated as the difference between the co-registered infarct volumes on MRI and CTP divided by the time interval between the scans, with fast inter-hospital growth ≥ 5ml/h. The hypoperfusion intensity ratio (HIR) was defined as the ratio of the volumes of Tmax >6s and Tmax >10s, and the CBV index as the ratio of mean CBV values within the Tmax >6s volume and the mean CBV in normal brain regions. An automated collateral score, based on the HIR and CBV index, was calculated from the CTP images at the PSC ( Fig 1A ). Results: Of 183 patients who were included, 111 (61%) were classified as having good collaterals and 72 (39%) as poor. Patients with poor collaterals experienced more rapid early infarct growth (median 2.19 ml/h IQR [0.32, 5.46] vs 7.92 [4.23, 16.23]; p-value <0.001) and had worse 90-day functional outcomes (p=0.01). The combined collateral score, based on both HIR and CBVindex, showed a trend towards better prediction of fast infarct growth compared to HIR alone (HIR ≥ 0.40 = poor collaterals) and CBV alone (CBVindex < 0.85 = poor collaterals) ( Fig 1B ). Conclusion: A perfusion collateral score, based on HIR and CBV index, is strongly associated with inter-hospital infarct growth rate and functional outcome. This automated tool can aid in patient selection for (neuroprotective) treatment strategies and transfer decisions.
