A Comparison of CT Perfusion Output of RapidAI and Viz.ai Software in the Evaluation of Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Automated CTP postprocessing packages have been developed for managing acute ischemic stroke. These packages use image processing techniques to identify the ischemic core and penumbra. This study aimed to investigate the agreement of decision-making rules and output derived from RapidAI and Viz.ai software packages in early and late time windows and to identify predictors of inadequate quality CTP studies. MATERIALS AND METHODS: One hundred twenty-nine patients with acute ischemic stroke who had CTP performed on presentation were analyzed by RapidAI and Viz.ai. Volumetric outputs were compared between packages by performing Spearman rank-order correlation and Wilcoxon signed-rank tests with subanalysis performed at early (<6 hours) and extended (>6 hours) time windows. The concordance of selecting patients on the basis of DAWN and DEFUSE 3 eligibility criteria was assessed using the McNemar test. RESULTS: One hundred eight of 129 patients were found to have adequate-quality studies. Spearman rank-order correlation coefficients were calculated on time-to-maximum >6-second volume, time-to-maximum >10-second volume, CBF <30% volume, mismatch volume, and mismatch ratio between both software packages with correlation coefficients of 0.82, 0.65, 0.77, 0.78, 0.59, respectively. The Wilcoxon signed-rank test was also performed on time-to-maximum >6-second volume, time-to-maximum >10-second volume, CBF <30% volume, mismatch volume, and mismatch ratio with P values of .30, .016, <.001, .03, <.001, respectively. In a 1-sided test, CBF <30% was greater in Viz.ai (P < .001). Although this finding resulted in statistically significant differences, it did not cause clinically significant differences when applied to the DAWN and DEFUSE 3 criteria. A lower ejection fraction predicted an inadequate study in both software packages (P = .018; 95% CI, 0.01-0.113) and (P = .024; 95% CI, 0.008-0.109) for RapidAI and Viz.ai, respectively. CONCLUSIONS: Penumbra and infarct core predictions between Rapid and Viz.ai correlated but were statistically different and resulted in equivalent triage using DAWN and DEFUSE3 criteria. Viz.ai predicted higher ischemic core volumes than RapidAI. Viz.ai predicted lower combined core and penumbra values than RapidAI at lower volumes and higher estimates than RapidAI at higher volumes. Clinicians should be cautious when using different software packages for clinical decision-making.

A Comparative Study of Hemorrhagic Conversion Patterns After Stroke Thrombolysis With Alteplase Versus Tenecteplase.

BACKGROUND AND PURPOSE: Tenecteplase is the thrombolytic drug of choice for acute ischemic stroke (AIS) as it has unique pharmacologic properties, along with results demonstrating its non-inferiority compared to alteplase. However, there are contradictory data concerning the risk of intracranial hemorrhage. The purpose of the study was to report the rate and patterns of symptomatic intracranial hemorrhage (sICH) in AIS patients after thrombolysis with tenecteplase compared to alteplase. METHODS: This is a retrospective cohort study with data collected 90 days before and after the change from alteplase to tenecteplase from 15 Texas stroke centers. The primary endpoint is the incidence of sICH according to the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST) and European Cooperative Acute Stroke Study III (ECASS-3) criteria. The secondary endpoints are the radiographic pattern of hemorrhagic conversion according to the Heidelberg bleeding classification (HBC). RESULTS: A total of 431 patients were eligible for thrombolytic therapy. Half of the cohort received alteplase (n=216), and the other half received tenecteplase (n=215). The average age of the alteplase group was 62.94 years old (SD=15.12) and 64.45 years old (SD=14.51) for the tenecteplase group. Seven patients in the alteplase group (3.2%) and 14 (6.5%) in the tenecteplase group had sICH, with an odds ratio of 1.44 (95% CI 0.60-3.43; P=0.41). An increased National Institutes of Health Stroke Scale (NIHSS) score on arrival (1.06; 95% CI 1.0004-1.131; P=0.04) was a statistically significant predictor of sICH. Tenecteplase was associated with a statistically significant increase in HBC-3 (P=0.040) over alteplase. CONCLUSIONS: Compared with alteplase, our study revealed a higher rate of sICH with tenecteplase that was not statistically significant and a higher rate of HBC-3 hemorrhages that was statistically significant. The proposed mechanism of bleeding is hemorrhagic conversion in clinically silent infarcts and contusions underlying the lesions. Further studies are needed to confirm our findings and determine predictive risk factors.

Use of angled-tip aspiration catheters is associated with a lower cost of thrombectomy in patients with acute ischemic stroke secondary to large and medium vessel occlusions.

BACKGROUND: Recently, the angled-tip Zoom™ aspiration catheters were introduced. The tip is designed to improve suction force for clot retrieval. We evaluated the possibility of reducing procedure costs when using angled-tip catheters and compared the safety and angiographic effectiveness of angled-tip versus straight-tip catheters. METHODS: We conducted a retrospective single-center cohort study involving patients with acute ischemic stroke due to large and medium vessel occlusions. The patients were divided into two groups: the post-Zoom group, in which angled-tip aspiration catheters were used and the pre-Zoom group, in which traditional straight-tip catheters were employed. RESULTS: A total of 163 patients were included; 95 (58.3%) in the pre-Zoom group and 68 (41.7%) in the post-Zoom group. The groups were well-matched at entry. The post-Zoom group demonstrated a significant decrease in mean procedure cost ($9728 vs. $12,127; p = 0.002), shorter time to achieve modified thrombolysis in cerebral infarction ≥2b reperfusion (38.30 min vs. 53.26 min; p = 0.018), and shorter puncture to procedure completion time (46.42 min vs. 62.38 min; p = 0.022). Additionally, the mean procedural cost when using the ADAPT technique supported by the Zoom catheters was significantly lower than the Solumbra technique ($5754 ± $2806 vs. $13,498 ± $3244, p < 0.001). There were no differences in the rate of hemorrhage between the pre-Zoom group (17.9%) and the post-Zoom group (20.6%), p = 0.690. CONCLUSION: The study demonstrated significant benefits, including cost reduction and shorter time to achieve reperfusion in patients treated with Zoom aspiration catheters. These findings support the use of angled-tip catheters in acute ischemic stroke management.

Viz LVO versus Rapid LVO in detection of large vessel occlusion on CT angiography for acute stroke.

BACKGROUND: Endovascular thrombectomy improves outcomes and reduces mortality for large vessel occlusion (LVO) and is time-sensitive. Computer automation may aid in the early detection of LVOs, but false values may lead to alarm desensitization. We compared Viz LVO and Rapid LVO for automated LVO detection. METHODS: Data were retrospectively extracted from Rapid LVO and Viz LVO running concurrently from January 2022 to January 2023 on CT angiography (CTA) images compared with a radiologist interpretation. We calculated diagnostic accuracy measures and performed a McNemar test to look for a difference between the algorithms' errors. We collected demographic data, comorbidities, ejection fraction (EF), and imaging features and performed a multiple logistic regression to determine if any of these variables predicted the incorrect classification of LVO on CTA. RESULTS: 360 participants were included, with 47 large vessel occlusions. Viz LVO and Rapid LVO had a specificity of 0.96 and 0.85, a sensitivity of 0.87 and 0.87, a positive predictive value of 0.75 and 0.46, and a negative predictive value of 0.98 and 0.97, respectively. A McNemar test on correct and incorrect classifications showed a statistically significant difference between the two algorithms' errors (P=0.00000031). A multiple logistic regression showed that low EF (Viz P=0.00125, Rapid P=0.0286) and Modified Woodcock Score >1 (Viz P=0.000198, Rapid P=0.000000975) were significant predictors of incorrect classification. CONCLUSION: Rapid LVO produced a significantly larger number of false positive values that may contribute to alarm desensitization, leading to missed alarms or delayed responses. EF and intracranial atherosclerosis were significant predictors of incorrect predictions.

A Rare Case of Cerebral Vasospasm Secondary to Primary Intraventricular Hemorrhage With an Immediate Improvement in Neurological Status Following Intra-arterial Therapy.

Symptomatic vasospasm following aneurysmal subarachnoid hemorrhage (SAH) occurs in roughly 30% of cases. However, vasospasm after primary intraventricular hemorrhage (IVH) is rare and described in only a handful of case reports and small retrospective studies. We present a patient with primary IVH. A conventional cerebral angiogram ruled out vascular anomalies but demonstrated severe diffuse cerebral vasospasm. The patient was treated with intra-arterial vasodilators, resulting in an immediate and profound improvement in the patient's neurological examination. Several days later, the patient had another decline in neurological status that immediately resolved after treatment with intra-arterial therapy. To our knowledge, this is the first reported case of a profound and immediate improvement in neurological examination following intra-arterial vasodilator administration.