Publications by authors named "Janet Mei"

Background: Pretreatment CT perfusion (CTP) marker relative cerebral blood volume (rCBV) < 42% lesion volume has recently shown to predict poor collateral status and poor 90-day functional outcome. However, there is a paucity of studies assessing its association with hemorrhagic transformation (HT). Here, we aim to assess the relationship between rCBV < 42% lesion volume with HT.

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The relative level of functional impairment in stroke patients is a significant determinant of post-acute care. The Activity Measure for Post Acute Care 6-Clicks (AM-PAC) scores for basic mobility and daily activity are rapid standardized assessments whose utilities in predicting long-term stroke outcomes have not yet been studied. We performed a retrospective analysis of acute ischemic stroke patients and their outcomes.

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Background And Purpose: Acute ischemic stroke due to anterior circulation large-vessel occlusion (AIS-LVO) remains a leading cause of disability despite successful reperfusion therapies. Prolonged venous transit (PVT) has emerged as a potential prognostic imaging biomarker in AIS-LVO. We aimed to investigate whether PVT is associated with a decreased likelihood of excellent functional outcome (modified Rankin Scale [mRS] score of 0-1 at 90 days) after successful reperfusion.

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Background And Purpose: Prolonged venous transit (PVT+) is a marker of venous outflow; it is defined as the presence or absence of time-to-maximum ≥10 seconds timing in either the superior sagittal sinus or torcula. This novel perfusion imaging-based metric has been associated with higher odds of mortality and lower odds of functional recovery. This study aims to assess the relationship between PVT on admission perfusion imaging and length of hospital stay in large vessel occlusion strokes successfully reperfused with mechanical thrombectomy.

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Background And Purpose: Mechanical thrombectomy (MT) is the treatment standard for large vessel occlusion (LVO) stroke. Under current guidelines, only patients with smaller ischemic core volumes (ICV) are eligible for MT. Thus, it is of interest to quickly estimate ICV in stroke patients.

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: Pretreatment CTA-based Cortical Vein Opacification Score (COVES) has been shown to predict good functional outcomes at 90 days in patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO). This is thought to be related to its ability to measure collateral status (CS). However, its association with the reference standard test, the DSA-based American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score, has yet to be established.

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Article Synopsis
  • Intracranial aneurysms (IAs) are a leading cause of subarachnoid hemorrhage, and using the Neuroform Atlas stent (NAS) with coiling is more effective than coiling alone for treatment.
  • The study conducted a systematic review and meta-analysis of 42 studies covering 2434 participants to evaluate the efficacy and safety of NAS, analyzing outcomes like aneurysm occlusion rates and related adverse events.
  • Results showed high occlusion success (95% overall), favorable modified Rankin Scale scores indicating good patient outcomes (93% mRS grade 0), and low adverse event rates (≤ 5%), though the study noted limitations in specific mortality data and the lack of comparative studies
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Background And Aim: Recent studies have shown that the CT Perfusion (CTP) parameter of rCBV < 42 % lesion volume can predict 90-day functional outcomes in stroke patients. However, its correlation with discharge outcomes, including functional dependence, has not been investigated. Our study aims to evaluate the relationship between rCBV < 42 % and poor functional outcomes at discharge, defined as a modified Rankin score (mRS) of 3 or higher.

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Background: Recent advances have highlighted the efficacy of endovascular thrombectomy (EVT) in patients with large ischemic core stroke, yet a significant portion still experience very poor outcomes, defined as a 90-day modified Rankin Score (mRS) of 5-6. This study aims to investigate the hypoperfusion intensity ratio (HIR) as a prognostic imaging parameter for these outcomes.

Methods: In a multicenter retrospective cohort study, data from consecutive patients undergoing EVT for acute ischemic stroke with large vessel occlusion (AIS-LVO) at two comprehensive stroke centers were analyzed.

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Background: Mechanical thrombectomy (MT) is the treatment standard in eligible patients with acute ischemic stroke (AIS) secondary to large vessel occlusions (LVO). Studies have shown that good collateral status is a strong predictor of MT efficacy, thus making collateral status important to quickly assess. The Los Angeles Motor Scale is a clinically validated tool for identifying LVO in the field.

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Article Synopsis
  • Ischemic strokes from isolated posterior cerebral artery (PCA) occlusions, though representing only 5% of strokes, lead to severe quality of life issues due to vision problems and thalamic involvement, highlighting the need for better management guidelines.
  • A study analyzed 32 patients with isolated PCA occlusions to assess the relationship between perfusion imaging parameters and clinical outcomes, using the NIH Stroke Scale (NIHSS) at discharge as the primary measure.
  • Results indicated significant correlations between NIHSS scores and perfusion parameters, particularly time-to-maximum (Tmax) and cerebral blood volume (CBV), suggesting that advanced imaging may enhance PCA stroke management, necessitating further validated research in this area.
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Article Synopsis
  • Recent trials show that mechanical thrombectomy is effective for treating acute ischemic stroke, but there's a need for standardized imaging measures to better select patients.
  • This study analyzed data from patients with large vessel occlusion at Johns Hopkins to find the computed tomography perfusion parameter linked to worse outcomes.
  • The results indicated that a cerebral blood volume (CBV) of less than 42% and ischemic cores over 68 mL strongly predicted unfavorable 90-day outcomes, with a high area under the curve, suggesting this threshold could help guide patient selection for treatment.
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  • Distal medium vessel occlusions (DMVOs) significantly contribute to acute ischemic stroke (AIS), with collateral status (CS) affecting the progression of ischemic damage.
  • A study analyzed 130 AIS-DMVO patients to identify baseline characteristics linked to CS, finding that good CS was present in 34% of patients.
  • Results showed that lower NIHSS and LAMS scores were associated with good CS; patients with poor CS were more likely to experience moderate to severe strokes, while those with good CS had a higher chance of minor strokes.
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The pretreatment CT perfusion (CTP) marker the relative cerebral blood volume (rCBV) < 42% lesion volume has recently been shown to predict 90-day functional outcomes; however, studies assessing correlations of the rCBV < 42% lesion volume with other outcomes remain sparse. Here, we aim to assess the relationship between the rCBV < 42% lesion volume and the reference standard digital subtraction angiography (DSA)-derived American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN) collateral score, hereby referred as the DSA CS. In this retrospective evaluation of our prospectively collected database, we included acute stroke patients triaged by multimodal CT imaging, including CT angiography and perfusion imaging, with confirmed anterior circulation large vessel occlusion between 1 September 2017 and 1 October 2023.

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Background: Distal medium vessel occlusions (DMVOs) contribute substantially to the incidence of acute ischemic strokes (AIS) and pose distinct challenges in clinical management and prognosis. Neuroimaging techniques, such as Fluid Attenuation Inversion Recovery (FLAIR) imaging and cerebral blood volume (CBV) index derived from perfusion imaging, have significantly improved our ability to assess the impact of strokes and predict their outcomes. The primary objective of this study was to investigate relationship between follow-up infarct volume (FIV) as assessed by FLAIR imaging in patients with DMVOs.

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Ischemic strokes in young adults are increasing in incidence and have emerged as a public health issue. The radiological features are not only diagnostic in identifying ischemic infarctions but also provide important clues in the investigation of the underlying causes or in the identification of risk factors. According to the different imaging patterns associated with ischemic stroke in young adults, the causes can be classified into 5 categories: cardioembolism, large vessel vasculopathy, small vessel vasculopathy, toxic-metabolic, and hypercoagulable disorders.

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Carotid artery webs are shelf-like protrusions of intimal fibrous tissue arising from the posterior wall of the carotid bulb, found to have a 2.3% prevalence in the United States. Previous studies have demonstrated its association with ipsilateral anterior circulation stroke.

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Background: Mitochondrial disease is a family of genetic disorders characterized by defects in the generation and regulation of energy. Epilepsy is a common symptom of mitochondrial disease, and in the vast majority of cases, refractory to commonly used antiepileptic drugs. Ferroptosis is a recently-described form of iron- and lipid-dependent regulated cell death associated with glutathione depletion and production of lipid peroxides by lipoxygenase enzymes.

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Ferroptosis is a form of programmed cell death associated with inflammation, neurodegeneration, and ischemia. Vitamin E (alpha-tocopherol) has been reported to prevent ferroptosis, but the mechanism by which this occurs is controversial. To elucidate the biochemical mechanism of vitamin E activity, we systematically investigated the effects of its major vitamers and metabolites on lipid oxidation and ferroptosis in a striatal cell model.

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