Distal mechanical thrombectomy using beveled tip aspiration zoom catheters: A preliminary study.

INTRODUCTION: Distal medium vessel occlusion (DVO) thrombectomy has been shown to be efficacious with safety profiles comparable to large vessel occlusion (LVO) thrombectomy. A novel, highly-trackable, bevel-tipped Zoom 35 catheter can be used as an aspiration catheter for DVO thrombectomy. METHODS: This is a retrospective, single-arm, multi-institutional observational study evaluating the efficacy and safety of aspiration thrombectomy for DVO using the Zoom 35 catheter. Patient demographics, presenting and discharge NIHSS, primary and rescue thrombectomy, site of occlusion, TICI score, and intracranial hemorrhage were chart abstracted. Descriptive statistics were used to evaluate the efficacy and safety of thrombectomy. RESULTS: Fourteen patients (mean age 66.64 ± 13.75 years) were included. The mean NIHSS at presentation was 10.79 ± 5.48, and the mean ASPECTS was 9.00 ± 0.89. Nine patients (64.3%) received tPA. Primary occlusion location was M3 in nine cases (64.3%), M2/M3 junction in two cases (14.3%), A2 in one case (7.1%), A3 in one case (7.1%), and P1 in one case (7.1%). TICI scores were 3 in seven cases (50.0%), 2C in three cases (21.4%), and 2B in four cases (28.6%). There was one postoperative SAH (7.1%) and one asymptomatic ICH (7.1%). Mean discharge NIHSS was 3.38 ± 4.44, with a mean decrease of 7.31 from presentation (p < 0.0001, t-test). CONCLUSION: Zoom 35 beveled-tip aspiration microcatheters are highly trackable and associated with improved radiographic and clinical outcomes for the treatment of DVO with a good safety profile.

Robotic Diagnostic Cerebral Angiography: A Multicenter Experience of 113 Patients.

BACKGROUND: Neurointerventional robotic systems have potential to reduce occupational radiation, improve procedural precision, and allow for future remote teleoperation. A limited number of single institution case reports and series have been published outlining the safety and feasibility of robot-assisted diagnostic cerebral angiography. METHODS: This is a multicenter, retrospective case series of patients undergoing diagnostic cerebral angiography at three separate institutions - University of California, Davis (UCD); University of California, Los Angeles (UCLA); and University of California, San Francisco (UCSF). The equipment used was the CorPath GRX Robotic System (Corindus, Waltham, MA). RESULTS: A total of 113 cases were analyzed who underwent robot-assisted diagnostic cerebral angiography from September 28, 2020 to October 27, 2022. There were no significant complications related to use of the robotic system including stroke, arterial dissection, bleeding, or pseudoaneurysm formation at the access site. Using the robotic system, 88 of 113 (77.9%) cases were completed successfully without unplanned manual conversion. The principal causes for unplanned manual conversion included challenging anatomy, technical difficulty with the bedside robotic cassette, and hubbing out of the robotic system due to limited working length. For robotic operation, average fluoroscopy time was 13.2 min (interquartile range (IQR), 9.3 to 16.8 min) and average cumulative air kerma was 975.8 mGY (IQR, 350.8 to 1073.5 mGy). CONCLUSIONS: Robotic cerebral angiography with the CorPath GRX Robotic System is safe and easily learned by novice users without much prior manual experience. However, there are technical limitations such as a short working length and an inability to support 0.035" wires which may limit its widespread adoption in clinical practice.

Aneurysmal subarachnoid hemorrhage in pregnancy: National trends of treatment, predictors, and outcomes.

INTRODUCTION: Aneurysmal subarachnoid hemorrhage (aSAH) is a rare event associated with significant pregnancy-associated maternal and neonatal morbidity and mortality. The optimal treatment strategy and clinical outcome of aSAH in pregnancy remains unclear. We aimed to investigate the treatment utilizations and outcomes of aSAH in pregnant people. METHODS: Using the 2010-2018 National Inpatient Sample, we identified all birth hospitalizations of women between ages of 18 to 45 associated with subarachnoid hemorrhage and aneurysm treatment were included. Multivariate analyses were used to evaluate the effect of pregnancy state, mode of treatment of aneurysms, severity of subarachnoid hemorrhage on mortality and discharge destination of this cohort. Trends in mode of treatment utilized for aneurysmal treatment in this time interval was evaluated. RESULTS: 13,351 aSAH with treatment were identified, of which 440 were associated with pregnancy. There was no significant difference in mortality or rate of discharge to home in pregnancy related hospitalization. Worse aSAH severity, chronic hypertension, and smaller hospital size was associated with significantly higher rate of mortality from aSAH during pregnancy. Worse aSAH severity was associated with lower rate of discharge to home. Like the non-pregnant cohort, the treatment of ruptured aneurysms in pregnancy are increasingly through endovascular approaches. The mode of treatment does not change the mortality or discharge destination. CONCLUSIONS: Pregnancy does not alter mortality or the discharge destination for aSAH. Ruptured aneurysms during pregnancy are increasingly treated endovascularly. Mode of aneurysm treatment does not affect mortality or discharge destination in pregnancy.

Rescue Intracranial Balloon Angioplasty with or without Stent Placement in Acute Strokes with Intracranial Atherosclerotic Disease.

BACKGROUND: Optimal management of acute ischemic stroke (AIS) secondary to intracranial atherosclerotic disease (ICAD) refractory to conventional mechanical thrombectomy remains unclear. We aimed to investigate the clinical outcome of patients undergoing rescue intracranial balloon angioplasty with or without stent placement in the setting of AIS in our institution. METHODS: This is a retrospective single-arm observational study to evaluate the efficacy and safety of rescue balloon angioplasty with or without stent placement in emergent large vessel occlusion (EVLO) strokes with underlying ICAD. We included all patients undergoing such rescue intervention within 24 hours of AIS presentation with EVLO between 2017 and 2021. We further evaluated stent or vessel reocclusion. RESULTS: Of 20 patients undergoing rescue intervention, 3 cases achieved adequate recanalization of artery using balloon angioplasty alone. Seventeen patients required stent placement. Fourteen (70%) procedures resulted in National Institutes of Health Stroke Scale improvement in postprocedure and upon discharge. Among 6 (30%) procedures with worsening neurological measures, 3 had reoccluded stent 24-48 hours after procedure, 2 had symptomatic hemorrhagic conversion, and 1 had perforator occlusion. Nine patients (45%) had favorable functional outcome (modified Rankin Scale ≤2) at discharge, unchanged or improved at 3-month follow-up. The median modified Rankin Scale score was 4 (Interquartile range: 1.75-4) at discharge, improving to 3 (Interquartile range: 0-4) at 3-month follow-up. Two patients (10%) died during hospital stay. CONCLUSIONS: Rescue angioplasty with or without stenting can lead to significant clinical improvement in patients with ICAD presenting with ELVO and refractory to thrombectomy; however, this procedure is associated with a high rate of morbidity in acute setting.

Endovascular Treatment of Large Vessel Occlusion Strokes Caused by Infective Endocarditis: A Systematic Review, Meta-Analysis, and Case Presentation.

Thromboembolic events such as acute ischemic strokes are frequently seen in patients with infective endocarditis (IE). It is generally recommended that the administration of intravenous thrombolytics is avoided in these patients as they might encounter a higher risk of intracranial hemorrhages. In this setting, particularly with a large vessel occlusion (LVO), a mechanical thrombectomy may be an alternative option. In this systematic review and meta-analysis, we aimed to investigate the outcomes and safety of mechanical thrombectomies for LVO stroke patients secondary to IE. A search strategy was developed and we searched PubMed, Scopus, Web of Sciences, and Embase using the words "infective endocarditis", "stroke", and "mechanical thrombectomy". Including 6 studies and 120 patients overall, this study showed that a mechanical thrombectomy might reduce the National Institute of Health Stroke Scale (NIHSS), with a weighted mean difference of -3.06 and a 95% CI of -4.43 to -1.70. The pooled rate of symptomatic intracranial hemorrhages and all-cause mortality were also determined to be 15% (95% CI: 4-47%) and 34% (95% CI:14-61%), respectively. The results of this study showed that a mechanical thrombectomy might be an effective and reasonably safe option for the treatment of LVO strokes caused by IE. However, more large-scale studies are needed to consolidate these results.

Reconstruction of carotid stenosis hemodynamics based on guidewire pressure data and computational modeling.

A comparative analysis between intravascular guidewire-obtained and computational fluid dynamic (CFD) flow velocity and pressure data using simplified carotid stenosis models was performed. This information was used to evaluate the viability of using guidewire pressure data to provide inlet conditions for CFD flow, and to study the relationship between stenotic length and hemodynamic behavior. Carotid stenosis models differing in diameter and length were prepared and connected to a vascular pulsatile flow simulator. Time-dependent flow velocity and pressure measurements were taken by microcatheter guidewires and compared with CFD data. Guidewire and CFD-generated pressure profiles matched closely in all measurement locations. The guidewire was unable to reliably measure flow velocity at areas associated with higher CFD flow velocities (r = 0.92). CFD results showed that an increased length of stenosis generated expansive regions of elevated wall shear stress (WSS) within and distal to the stenosis. Low WSS was found immediately outside the stenosis outlet. An increase in stenotic length produced higher flow velocities with minimal lengthening of the distal high velocity flow jet due to faster dissipation of translational kinetic energy through turbulence. We found the accuracy of guidewire-obtained velocity measurements is limited to regions unaffected by disturbed flow. WSS and turbulence behavior distal to the stenosis may be important markers to evaluate the severity of atherosclerotic progression as a function of stenotic length.

A new aspiration device equipped with a hydro-separator for acute ischemic stroke due to challenging soft and stiff clots.

OBJECTIVE: Fragile soft clots and stiff clots remain challenging in the treatment of acute ischemic stroke. This study aims to investigate the impact of clot stiffness on the efficacy of thrombectomy devices and a new aspiration catheter with a hydro-separator. METHODS: The Neurostar aspiration catheter has a novel hydro-separator technology that macerates clots by a stream of saline inside the catheter. The Neurostar catheter and two commercially available devices, the SOFIA aspiration catheter and Solitaire stent retriever, were tested in this study. We evaluated the efficacy of each device on clots with various stiffness in a simple in vitro model. We also assessed single-pass recanalization performance in challenging situations with large erythrocyte-rich clots and fibrin-rich clots in a realistic vascular model. RESULTS: We observed an inverse association between the clot stiffness and recanalization rates. The aspiration catheter, SOFIA ingested soft clots but not moderately stiff clots. When removing soft clots with the stent retriever, fragmentation was observed, although relatively stiff clots were well-integrated and removed. The Neurostar ingested soft clots similar to the aspiration catheter, and also aspirated stiff clots by continuous suction with hydro-separator. In the experiments with challenging clots, the Neurostar led to significantly higher recanalization rates than the stent retriever and aspiration catheter. CONCLUSIONS: The stiffness of the clots affected the efficacy of endovascular thrombectomy based on the type of device. The Neurostar catheter with hydro-separator resulted in better success rates than a commercially available aspiration catheter and stent retriever in this experimental model.

Endovascular biopsy of a sigmoid sinus lesion using a stent retriever and aspiration catheter.

A teenager with a history of acute myeloid leukemia presented with headache, nausea and blurry vision over a 2 week period. The MRI of the brain was concerning for the presence of a myeloid sarcoma within the right sigmoid sinus. For evaluation of venous obstruction and the underlying lesion the patient underwent a cerebral angiogram and transvenous biopsy of the sigmoid sinus lesion using a stent retriever and aspiration catheter. The tissue extracted was consistent with myeloid sarcoma. This pathologic finding was consistent with the recurrence of leukemia and guided the targeted oncologic treatment.

Pathophysiologic mechanisms of cerebral endotheliopathy and stroke due to Sars-CoV-2.

Cerebrovascular events have emerged as a central feature of the clinical syndrome associated with Sars-CoV-2 infection. This increase in infection-related strokes is marked by atypical presentations including stroke in younger patients and a high rate of hemorrhagic transformation after ischemia. A variety of pathogenic mechanisms may underlie this connection. Efforts to identify synergism in the pathophysiology underlying stroke and Sars-CoV-2 infection can inform the understanding of both conditions in novel ways. In this review, the molecular cascades connected to Sars-CoV-2 infection are placed in the context of the cerebral vasculature and in relationship to pathways known to be associated with stroke. Cytokine-mediated promotion of systemic hypercoagulability is suggested while direct Sars-CoV-2 infection of cerebral endothelial cells may also contribute. Endotheliopathy resulting from direct Sars-CoV-2 infection of the cerebral vasculature can modulate ACE2/AT1R/MasR signaling pathways, trigger direct viral activation of the complement cascade, and activate feed-forward cytokine cascades that impact the blood-brain barrier. All of these pathways are already implicated as independent mechanisms driving stroke and cerebrovascular injury irrespective of Sars-CoV-2. Recognizing the overlap of molecular pathways triggered by Sars-CoV-2 infection with those implicated in the pathogenesis of stroke provides an opportunity to identify future therapeutics targeting both Sars-CoV-2 and stroke thereby reducing the impact of the global pandemic.

Determinants of accuracy of freehand external ventricular drain placement by neurosurgical trainees.

BACKGROUND: The external ventricular drain (EVD) placement is one of the most common neurosurgical procedures. This operation is performed by freehand technique in the majority of cases; therefore, the operator's experience plays an important role in success and possible morbidity of this procedure. OBJECTIVE: To evaluate the accuracy and safety of EVD placement by junior neurosurgery residents and factors predicting accuracy of EVD placement. METHODS: This is a prospective cohort study conducted at our academic medical center, between September 2017 and August 2018. All patients 18 years or older who required EVD placement were included. The accuracy and complications of EVD placement were assessed in the first and second year resident cohorts as well as by their level of experience, using descriptive statistics. Univariate and multivariate models were used to assess predictive factors for optimal EVD. RESULTS: A total of 100 EVDs were placed in 100 patients during the study period. According to Kakarla classification, the catheter was optimally placed in 80% of cases. The first year residents had a significantly higher rate of suboptimal burr hole placement compared to the second year residents (66.7% versus 27.1%, p = 0.004). The trainees with less than 10 EVD placement experience also had a significantly higher rate of suboptimal burr hole placement (55.2% vs. 23.9%, p = 0.003), significantly longer duration of operation (43.1 min ± 14.9SD vs 34.2 min ± 9.6 p = 0.005), and significantly lower rate of optimal EVD location (85.9% versus 65.5%, p = 0.023). Optimal location of the burr hole was the only significant predictor of optimal EVD placement in multivariate analysis (OR 11.9, 95% CI 3.2-44.6, p < 0.001). CONCLUSIONS: Neurosurgery residents experience and optimal burr hole placement are the main predicators of accurate EVD placement.

Prevalence, Predictors, and Outcomes of Prolonged Mechanical Ventilation After Endovascular Stroke Therapy.

BACKGROUND: To investigate the rates, predictors, and outcomes of prolonged mechanical ventilation (≥ 96 h) following endovascular treatment (EVT) of ischemic stroke. METHODS: Hospitalizations with acute ischemic stroke and EVT were identified using validated codes in the National Inpatient Sample (2010-2015). The primary outcome was prolonged mechanical ventilation defined as ventilation ≥ 96 consecutive hours. We compared hospitalizations involving prolonged ventilation following EVT with those that did not involve prolonged ventilation. Propensity score matching was used to adjust for differences between groups. Clinical predictors of prolonged ventilation were assessed using multivariable conditional logistic regression analyses. RESULTS: Among the 34,184 hospitalizations with EVT, 5087 (14.9%) required prolonged mechanical ventilation. There was a decline in overall intubation and prolonged ventilation during the study period. On multivariable analysis, history of heart failure [OR 1.28 (95% CI 1.05-1.57)] and diabetes [OR 1.22 (95% CI 1-1.50)] was independent predictors of prolonged ventilation following EVT. In a sensitivity analysis of anterior circulation stroke only, heart failure [OR 1.3 (95% CI 1.10-1.61)], diabetes [OR 1.25 (95% CI 1.01-1.57)], and chronic lung disease [OR 1.31 (95% CI 1.03-1.66)] were independent predictors of prolonged ventilation. The weighted proportions of in-hospital mortality, post-procedural shock, acute renal failure, and intracerebral hemorrhage were higher in the prolonged ventilation group. CONCLUSIONS: Among a nationally representative sample of hospitalizations, nearly one-in-six patients had prolonged mechanical ventilation after EVT. Heart failure and diabetes were significantly associated with prolonged mechanical ventilation following EVT. Prolonged ventilation was associated with significant increase in in-hospital mortality and morbidity.

Reperfusion Therapy Frequency and Outcomes in Mild Ischemic Stroke in the United States.

BACKGROUND AND PURPOSE: More than half of patients with acute ischemic stroke have minor neurological deficits; however, the frequency and outcomes of reperfusion therapy in regular practice has not been well-delineated. METHODS: Analysis of US National Inpatient Sample of hospitalizations with acute ischemic stroke and mild deficits (National Institutes of Health Stroke Scale [NIHSS] score 0-5) from October 1, 2016, to December 31, 2017. Patient- and hospital-level characteristics associated with use and outcome of reperfusion therapies were analyzed. Primary outcomes included excellent discharge disposition (discharge to home without assistance); poor discharge disposition (discharge to facility or death); in-hospital mortality; and radiological intracranial hemorrhage. RESULTS: Among 179 710 acute ischemic stroke admissions with recorded NIHSS during the 15-month study period, 103 765 (57.7%) had mild strokes (47.3% women; median age, 69 [interquartile range, 59-79] years; median NIHSS score of 2 [interquartile range, 1-4]). Considering reperfusion therapies among strokes with documented NIHSS, mild deficit hospitalizations accounted for 40.0% of IVT and 10.7% of mechanical thrombectomy procedures. Characteristics associated with IVT and with mechanical thrombectomy utilization were younger age, absence of diabetes, higher NIHSS score, larger/teaching hospital status, and Western US region. Excellent discharge outcome occurred in 48.2% of all mild strokes, and in multivariable analysis, was associated with younger age, male sex, White race, lower NIHSS score, absence of diabetes, heart failure, and kidney disease, and IVT use. IVT was associated with increased likelihood of excellent outcome (odds ratio, 1.90 [95% CI, 1.71-2.13], P<0.001) despite an increased risk of intracranial hemorrhage (odds ratio, 1.41 [95% CI, 1.09-1.83], P<0.001). CONCLUSIONS: In national US practice, more than one-half of acute ischemic stroke hospitalizations had mild deficits, accounting for 4 of every 10 IVT and 1 of every 10 mechanical thrombectomy treatments, and IVT use was associated with increased discharge to home despite increased intracranial hemorrhage.

Targeted Radiation Therapy Can Treat Myxomatous Cerebral Aneurysms.

BACKGROUND: Neoplastic cerebral aneurysms are rare presentations of cardiac myxomas. The natural history of such aneurysms is not well understood, and the optimal treatment strategy remains unclear. Clipping and coiling are effective, although can carry significant morbidity. Chemotherapy and radiation can theoretically be effective, although their clinical efficacy remains to be proven. CASE DESCRIPTION: Here we describe a patient with cardiac myxoma presenting with multiple progressively fusiform aneurysms. These aneurysms were noted to be growing during conservative monitoring given the eloquent location. Subsequently, the patient underwent multiple sessions of targeted radiation therapy, which lead to obliteration, shrinkage, or halting in growth of these aneurysms. CONCLUSIONS: Low-dose targeted radiation therapy can be safe and effective in treatment of neoplastic myxomatous aneurysms.

In Vitro Modeling of Human Brain Arteriovenous Malformation for Endovascular Simulation and Flow Analysis.

BACKGROUND: Current in vitro models for human brain arteriovenous malformation (AVM) analyzing the efficacy of embolic materials or flow conditions are limited by a lack of realistic anatomic features of complex AVM nidus. The purpose of this study was to evaluate a newly developed in vitro AVM model for embolic material testing, preclinical training, and flow analysis. METHODS: Three-dimensional (3D) images of the AVM nidus were extracted from 3D rotational angiography from a patient. Inner vascular mold was printed using a 3D printer, coated with polydimethylsiloxanes, and then was removed by acetone, leaving a hollow AVM model. Injections of liquid embolic material and 4-dimensional (4D) flow magnetic resonance imaging (MRI) were performed using the AVM models. Additionally, computational fluid dynamics analysis was performed to examine the flow volume rate as compared with 4D flow MRI. RESULTS: The manufacture of 3D in vitro AVM models delivers a realistic representation of human nidus vasculature and complexity derived from patients. The injection of liquid embolic agents performed in the in vitro model successfully replicated real-life treatment conditions. The model simulated the plug and push technique before penetration of the liquid embolic material into the AVM nidus. The 4D flow MRI results were comparable to computational fluid dynamics analysis. CONCLUSIONS: An in vitro human brain AVM model with realistic geometric complexities of nidus was successfully created using 3D printing technology. This AVM model offers a useful tool for training of embolization techniques and analysis of hemodynamics analysis, and development of new devices and materials.

Increased Rate of Successful First Passage Recanalization During Mechanical Thrombectomy for M2 Occlusion.

BACKGROUND: Mechanical thrombectomy (MT) is the standard of care for the treatment of acute ischemic stroke (AIS) caused by anterior circulation large-vessel occlusion. However, the true safety and efficacy of MT in medium-size vessel occlusions such as the M2 segment of the middle cerebral artery have yet to be completely defined. In this study, we analyze the safety and efficacy of MT in M2 occlusions compared with M1 occlusions. METHODS: A retrospective analysis was performed of patients with AIS secondary to M1 and M2 occlusions between 2011 and 2018. The inclusion criteria were 1) AIS secondary to M1 or M2 occlusion, 2) MT performed by stentrieval technique alone, aspiration technique, or combined stentrieval-aspiration techniques. Basic patient characteristics, number of passages, first passage recanalization success (≥TICI [Thrombolysis in Cerebral Ischemia] grade 2b), total recanalization success, hemorrhagic complications (including intracerebral hemorrhage [ICH] and subarachnoid hemorrhage), and clinical outcomes were compared between both groups. RESULTS: Two hundred and sixty patients met the inclusion criteria; 171 patients had M1 occlusion versus 89 with M2 occlusion. First passage recanalization success rate was significantly higher in the M2 group (55.1% vs. 39.2%; P = 0.015). Total recanalization success rate was higher in the M2 group but did not reach significance (83% vs. 75%; P = 0.128). Subarachnoid hemorrhage rate was significantly higher in the M2 group (25% vs. 12%; P = 0.010) but there was no difference for ICH complications (14.6% vs. 16.4%; P = 0.711). CONCLUSIONS: MT for M2 occlusions has similar overall efficacy to that for M1 occlusions, but with higher first-pass successful recanalization rates. MT for M2 occlusions has a higher risk of associated subarachnoid hemorrhage.

Role of Bedside Multimodality Monitoring in the Detection of Cerebral Vasospasm Following Subarachnoid Hemorrhage.

BACKGROUND: Detection of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) in patients with a poor clinical exam is challenging. Brain tissue oxygen tension monitoring (PbtO2) and cerebral microdialysis (CMD) can detect ischemia and metabolic derangements. Our aim was to evaluate efficacy of these modalities in real-time detection of DCI. METHODS: All patients with aSAH who underwent with multimodality monitoring (MMM) with PbtO2 and/or CMD between the years of 2013 and 2015 at our institution were retrospectively studied. Mean PbTO2, lactate to pyruvate ratio (LPR), and glucose over the 24-h period prior to each angiogram for evaluation and treatment of vasospasm were correlated to the extent of vasospasm observed in the hemisphere with the monitors. The average measurements were also compared in the setting of presence and absence of angiographically significant vasospasm. RESULTS: A total of ten patients with aSAH who underwent MMM were identified. PbtO2 decline correlates with severity of proximal vasospasm (r = -0.66). PbtO2 was significantly lower in the setting of vasospasm (17.6 vs. 25.8, p = 0.003), but LPR (34.5 vs. 26.8, p = 0.1) and glucose (0.8 vs. 1.1, p = 0.6) were not significantly different. CONCLUSION: Proximal vasospasm after aSAH is associated with MMM indicator of tissue ischemia and/or metabolic derangement. PbtO2 and CMD help in real-time detection and management of DCI.

Posterior Circulation Thrombectomy-pc-ASPECT Score Applied to Preintervention Magnetic Resonance Imaging Can Accurately Predict Functional Outcome.

BACKGROUND: There are currently no imaging criteria to identify patients who would benefit from endovascular recanalization of posterior circulation strokes. Applying the Posterior Circulation Alberta Stroke Program Early Computed Tomography Score (pc-ASPECTS) to magnetic resonance imaging (MRI) has been demonstrated to be an accurate predictor of functional outcome. Here, we aimed to evaluate the accuracy of the pc-ASPECTS with preintervention MRI as a predictor of functional outcome in a cohort undergoing endovascular recanalization. METHODS: This is a 15-year retrospective study of patients undergoing endovascular recanalization of posterior circulation with baseline MRI or computed tomography. We analyzed baseline imaging, clinical data, and type and timing of intervention to the functional outcome at 90 days. Using MRI pc-ASPECTS, we evaluated interrater reliability and accuracy in predicting functional outcome and compared them to the use of single-anatomic location for this function. RESULTS: Door-to-recanalization time in the MRI cohort was significantly longer (median: 8.7 vs. 2.7 hours, P = 0.03); however, functional outcome was not different. Within the MRI cohort, pc-ASPECTS and National Institutes of Health Stroke Scale were the only factors that were significantly different between the groups with good and bad functional outcome (P < 0.001). The area under the receiver operating characteristic curve for the pc-ASPECTS and good functional outcome was 0.96, with the optimal threshold of ≥8 resulting in positive predictive value of 90% and negative predictive value of 100%. CONCLUSIONS: Despite longer time to intervention with MRI as the initial imaging modality in posterior circulation strokes, it does not negatively affect the functional outcome. Pc-ASPECTS is an easy to use and accurate prognostic tool for the real-time evaluation of preintervention MRI in this population.

pH-weighted molecular MRI in human traumatic brain injury (TBI) using amine proton chemical exchange saturation transfer echoplanar imaging (CEST EPI).

Cerebral acidosis is a consequence of secondary injury mechanisms following traumatic brain injury (TBI), including excitotoxicity and ischemia, with potentially significant clinical implications. However, there remains an unmet clinical need for technology for non-invasive, high resolution pH imaging of human TBI for studying metabolic changes following injury. The current study examined 17 patients with TBI and 20 healthy controls using amine chemical exchange saturation transfer echoplanar imaging (CEST EPI), a novel pH-weighted molecular MR imaging technique, on a clinical 3T MR scanner. Results showed significantly elevated pH-weighted image contrast (MTRasym at 3 ppm) in areas of T2 hyperintensity or edema (P < 0.0001), and a strong negative correlation with Glasgow Coma Scale (GCS) at the time of the MRI exam (R2 = 0.4777, P = 0.0021), Glasgow Outcome Scale - Extended (GOSE) at 6 months from injury (R2 = 0.5334, P = 0.0107), and a non-linear correlation with the time from injury to MRI exam (R2 = 0.6317, P = 0.0004). This evidence suggests clinical feasibility and potential value of pH-weighted amine CEST EPI as a high-resolution imaging tool for identifying tissue most at risk for long-term damage due to cerebral acidosis.