Argye E Hillis

• Johns Hopkins Medicine

Background The pretreatment rCBV <42% lesion volume on CT Perfusion (CTP) has recently been shown to predict 90-day functional outcomes in stroke patients. However, its association with length of stay (LOS) has not yet been explored. This study aims to assess the relationship between rCBV <42% and prolonged LOS, defined as 7 days or longer. Method...

BACKGROUND Although many studies have suggested that white matter hyperintensity (WMH) severity predicts naming and aphasia severity in chronic poststroke aphasia, there are inconsistencies in the literature. WMHs are typically symmetrical in neurotypical controls, and measuring WMH in the contralateral hemisphere is likely the best option to estim...

Background Collateral status plays a crucial role in outcomes after acute ischemic stroke due to large vessel occlusion. Tissue‐level collaterals and venous outflow are key components following mechanical thrombectomy. This study evaluates the predictive performance of prolonged venous transit (PVT), cerebral blood volume index, and hypoperfusion i...

BACKGROUND Nonverbal cognitive deficits in poststroke aphasia remain poorly understood. They may result from direct stroke damage or disconnections of preserved cortical regions due to white matter injury, which may be worsened by white matter hyperintensities (WMH). Here, we examined the prevalence of nonverbal cognitive deficits in chronic postst...

Background and Purpose Venous outflow (VO) impairment predicts unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). Prolonged venous transit (PVT), a visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps, has been associated with 90-day mortality despite successful reperfus...

Purpose The Western Aphasia Battery–Revised (WAB-R) is often used for diagnosis of aphasia. However, persons scoring above the WAB-R diagnostic cutoff may still present with language difficulties indicative of aphasia. Identification of residual language challenges is critical for treatment referral or inclusion in research. We examined differences...

Background Recent trials of endovascular thrombectomy (EVT) for acute distal medium vessel occlusions (DMVOs) were negative but also used inconsistent imaging-based inclusion criteria, whereas many successful large vessel occlusion (LVO) EVT trials used empirically validated CT perfusion-based target mismatch (TMM) criteria: an ischemic penumbra (t...

When weighing potential risks versus benefits of reperfusion therapy, the functions likely to recover if blood flow can be restored should be considered. Because deep and motor areas often infarct relatively early in acute stroke, we hypothesized that reperfusion therapies improve predominantly cortical functions more than motor function. In this r...

Objective Dissociating Primary Progressive Aphasia (PPA) from Mild Cognitive Impairment (MCI) is an important, yet challenging task. Given the need for low-cost and time-efficient classification, we used low-density electroencephalography (EEG) recordings to automatically classify PPA, MCI and healthy control (HC) individuals. To the best of our kn...

Background The classification of patients with primary progressive aphasia (PPA) into variants is time-consuming, costly, and requires combined expertise by clinical neurologists, neuropsychologists, speech pathologists, and radiologists. Objective The aim of the present study is to determine whether acoustic and linguistic variables provide accur...

Background Acute ischaemic stroke (AIS) is a leading cause of mortality and disability globally, with volume contracted state (VCS), as indicated by an elevated blood urea nitrogen to creatinine (BUN/Cr) ratio, potentially influencing outcomes. This study investigates the association between VCS and clinical outcomes in patients with AIS due to lar...

Background and Purpose: Venous outflow (VO) impairment predicts unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). Prolonged venous transit (PVT), a visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps, has been associated with 90-day mortality despite successful reperfu...

Introduction: Pretreatment CT Perfusion (CTP) marker relative cerebral blood volume (rCBV) <42% lesion volume has recently been shown to predict poor collateral status (CS), infarct volume, and unfavorable 90-day functional outcomes. However, there are no studies assessing its association with hemorrhagic transformation (HT). This study aims to eva...

Introduction: Prolonged venous outflow (PVT+) is a surrogate marker for venous outflow. The PVT is defined as the presence or absence of time-to-maximum >= 10 seconds timing in either the superior saggital sinus or torcula on visual time-to-maximum maps from perfusion imaging. This novel metric has been shown to be associated with higher odds of mo...

Background The National Institutes of Health Stroke Scale (NIHSS) is widely used to assess stroke severity. While prior studies have identified subcortical regions where infarcts correlate with NIHSS scores, stroke symptoms can also arise from hypoperfusion, not just infarcts. Understanding the potential for neurological recovery post-reperfusion i...

Background and purpose Prolonged length of stay (LOS) following a stroke is associated with unfavorable clinical outcomes. Factors predicting LOS in medium vessel occlusion (MeVO), impacting up to 40% of acute ischemic stroke (AIS) cases, remain underexplored. This study aims to investigate the predictors of LOS in AIS-MeVO. Methods We conducted...

The cerebral blood volume index (CBV index) is a perfusion-based marker of collateral status. Several real-world data analyses from observational stroke cohorts have established relationships between this parameter and a range of favorable and unfavorable stroke outcomes. In this review, an overview is provided of the CBV index, within the context...

Background and Purpose Prolonged venous transit (PVT), derived from computed tomography perfusion (CTP) time‐to‐maximum ( T max ) maps, reflects compromised venous outflow (VO) in acute ischemic stroke due to large vessel occlusion (AIS‐LVO). Poor VO is associated with worse clinical outcomes, but pre‐treatment markers predictive of PVT are not wel...

Introduction The venous outflow profile (VOP) is a crucial yet often overlooked aspect affecting stroke outcomes. It plays a major role in the physiopathology of acute cerebral ischemia, as it accounts for both the upstream arterial collaterals and cerebral microperfusion. This enables it to circumvent the limitations of various arterial collateral...

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 rC...

Purpose The purpose of the study was to evaluate Verb Network Strengthening Treatment (VNeST) paired with the transcranial direct current stimulation (tDCS) of the left inferior frontal gyrus, which was compared to VNeST paired with a sham stimulation in primary progressive aphasia (PPA). Method A double-blind, within-subject, sham-controlled cros...

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 decrease...

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. Thi...

Background: 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. Meth...

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. The Los Angeles Motor Scale (LAMS) is a validated tool used t...

Background Pretreatment computed tomography perfusion parameter relative cerebral blood volume (rCBV) lesion volume has been shown to predict 90‐day modified Rankin Scale score in small‐core strokes with Alberta Stroke Program Early Computed Tomography Score ≥5, including those with medium‐vessel occlusions (mid and distal M2 segment occlusions)....

Background and purpose: 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 th...

Background Endovascular thrombectomy (EVT) has shown promise in randomized controlled trials (RCTs) for large ischemic core stroke patients, yet variability in core definition and onset-to-imaging time creates heterogeneity in outcomes. This study aims to clarify the prevalence and implications of core-perfusion mismatch (MM) versus no mismatch (No...

Background and purpose: Acute ischemic strokes caused by distal medium vessel occlusions (DMVO) represent a significant proportion of all stroke cases, yet the predictors of excellent functional outcomes in these patients remain poorly understood. This study aims to identify pretreatment computed tomography perfusion (CTP) parameters associated wi...

Introduction: The influence of the cerebellum in poststroke aphasia recovery is poorly understood. Despite the right cerebellum being identified as a critical region involved in both language and cognitive functions, little is known about functional connections between the cerebellum and bilateral cortical hemispheres following stroke. This study i...

Objective Venous outflow (VO) impairment predicts unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS‐LVO). Prolonged venous transit (PVT), a visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps, has been associated with unfavorable 90‐day functional outcomes despite successful...

Background and purpose Despite comprehensive evidence that supports the utility of aphasia therapy in persons with chronic (≥6 months) stroke-induced aphasia, the amount of therapy provided to patients in the United States is typically far less than what is likely necessary to maximize recovery. Two potential contributors to this discrepancy are li...

The hypoperfusion intensity ratio (HIR) is a quantitative metric used in vascular occlusion imaging to evaluate the extent of brain tissue at risk due to hypoperfusion. Defined as the ratio of tissue volume with a time-to-maximum (Tmax) of >10 seconds to that of >6 seconds, HIR assists in differentiating between the salvageable penumbra and the irr...

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 clinicall...

Sharing neuroimaging datasets enables reproducibility, education, tool development, and new discoveries. Neuroimaging from many studies are publicly available, providing a glimpse into progressive disorders and human development. In contrast, few stroke studies are shared, and these datasets lack longitudinal sampling of functional imaging, diffusi...

Background and Purpose Ischemic strokes due to isolated posterior cerebral artery (PCA) occlusions represent 5% of all strokes but have significant impacts on patients’ quality of life, primarily due to visual deficits and thalamic involvement. Current guidelines for acute PCA occlusion management are sparse, and the prognostic value of perfusion i...

In this randomized, double-blind, sham-controlled trial of Cerebellar Stimulation for Aphasia Rehabilitation (CeSAR), we will determine the effectiveness of cathodal tDCS (transcranial direct current stimulation) to the right cerebellum for the treatment of chronic aphasia (>6 months post stroke). We will test the hypothesis that cerebellar tDCS in...

BACKGROUND Recent large core trials have highlighted the effectiveness of mechanical thrombectomy (MT) in acute ischemic stroke with large vessel occlusion. Variable perfusion-imaging thresholds and poor Alberta Stroke Program Early Computed Tomography Score reliability underline the need for more standardized, quantitative ischemia measures for MT...

BACKGROUND Unfavorable clinical outcomes in patients with acute ischemic stroke caused by large‐vessel occlusions despite successful reperfusion have been associated with poor venous outflow. The objective of this study is to assess the relationship between prolonged venous transit (PVT), a novel perfusion imaging surrogate for poor venous outflow,...

Background Prolonged venous transit (PVT), defined as presence of time-to-maximum [Formula: see text] 10 s within the superior sagittal sinus (SSS) and/or torcula, is a novel, qualitatively assessed computed tomography perfusion surrogate parameter of venous outflow with potential utility in pretreatment acute ischemic stroke imaging for neuroprogn...

This scientific commentary refers to ‘Artificial intelligence classifies primary progressive aphasia from connected speech’ by Rezaii et al. (https://doi.org/10.1093/brain/awae196).

Background: Few investigations examined the relationship between microstructural white matter integrity and subacute post-stroke linguistic performance or the relationship between microstructural integrity and the recovery of language function. We examined two key questions: (1) How does subacute language performance, measured in single words and d...

Background: When weighing potential risks versus benefits of reperfusion therapy, the functions likely to recover if blood flow can be restored should be considered. Because deep and motor areas of the brain often infarct relatively early in acute stroke, we hypothesized that reperfusion therapies are more likely to improve language function and ne...

Individuals with Mild Cognitive Impairment (MCI), a transitional stage between cognitively healthy aging and dementia, are characterized by subtle neurocognitive changes. Clinically, they can be grouped into two main variants, namely patients with amnestic MCI (aMCI) and non-amnestic MCI (naMCI). The distinction of the two variants is known to be c...

Background: In the diagnostic criteria for lvPPA (Gorno-Tempini et al., 2011), “speech (phonologic) errors in spontaneous speech and naming” is a secondary criterion, but studies of naming error patterns in PPA have not found evidence to support this criterion. Furthermore, only a few studies have examined naming error patterns in PPA. Aims: In th...

Background and Purpose Distal medium vessel occlusions (DMVOs) are a significant contributor to acute ischemic stroke (AIS), with collateral status (CS) playing a pivotal role in modulating ischemic damage progression. We aimed to explore baseline characteristics associated with CS in AIS‐DMVO. Methods This retrospective analysis of a prospectivel...

Here, we review the literature on neurotypical individuals and individuals with post-stroke aphasia showing that right-hemisphere regions homologous to language network and other regions, like the right cerebellum, are activated in language tasks and support language even in healthy people. We propose that language recovery in post-stroke aphasia o...

Background: Identifying the characteristics of individuals who demonstrate response to an intervention allows us to predict who is most likely to benefit from certain interventions. Prediction is challenging in rare and heterogeneous diseases, such as primary progressive aphasia (PPA), that have varying clinical manifestations. We aimed to determin...

Pretreatment CT Perfusion (CTP) parameter rCBV < 42% lesion volume has recently been shown to predict 90-day mRS. In this study, we aim to assess the relationship between rCBV < 42% and a radiographic follow-up infarct volume delineated on FLAIR images. In this retrospective evaluation of our prospectively collected database, we included acute stro...

Background Collateral status (CS) is an important biomarker of functional outcomes in patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO). Pretreatment CT perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the relative cerebral blo...

BACKGROUND Hemorrhagic transformation (HT) is a major complication in patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy. However, HT in patients with AIS due to medium‐vessel occlusions has still not been well researched. In large‐vessel occlusions, collateral status is an important determinant of postprocedural HT, a...

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, ha...

Background Poor venous outflow (VO) profiles are associated with unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO), despite achieving successful reperfusion. The objective of this study is to assess the association between mortality and prolonged venous transit (PVT), a novel visual qualitative V...

Background: 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%...

In this randomized, double-blind, sham-controlled trial of Cerebellar Stimulation for Aphasia Rehabilitation (CeSAR), we will determine the effectiveness of cathodal tDCS (transcranial direct current stimulation) to the right cerebellum for the treatment of chronic aphasia (>6 months post stroke). We will test the hypothesis that cerebellar tDCS in...

Background/Purpose: Distal medium vessel occlusions (DMVOs) account for a large percentage of vessel occlusions resulting in acute ischemic stroke (AIS) with disabling symptoms. We aim to assess whether pretreatment CTP collateral status (CS) parameters can serve as imaging biomarkers for good clinical outcomes prediction in successfully recanalize...

Deficits in spoken discourse comprehension are common after left hemisphere (LH) and right hemisphere (RH) stroke. Thus, it is important to identify factors that facilitate comprehension and enhance communication between stroke survivors and their care partners. Emotional prosody and facial expression cues can facilitate comprehension, but this may...

Introduction: In large vessel occlusion (LVO) ischemic stroke patients, better functional outcomes are associated with achieving modified thrombolysis in cerebral infarction (mTICI) score 2C/3 in comparison to 2B. The purpose of this study was to identify pretreatment and interventional predictors of mTICI 2C/3 over 2B reperfusion in patients with...

Introduction: Collateral status imaging parameters are associated with predicting hemorrhagic transformation (HT) in acute ischemic stroke caused by large vessel occlusions. The purpose of this investigation is to examine the association between imaging biomarkers of poor collateral status and HT occurrence in distal medium vessel occlusion (DMVO)...

BACKGROUND The National Institutes of Health Stroke Scale is a widely accepted tool for structured graded neurological examination of stroke or suspected stroke in the hyperacute setting. Concerns have arisen about the use of its picture stimuli in a contemporary and global health context. Here, we present new stimuli prepared to serve the needs of...

Background/Purpose Distal medium vessel occlusions (DMVOs) account for a large percentage of vessel occlusions resulting in acute ischemic stroke (AIS) with disabling symptoms. We aim to assess whether pretreatment quantitative CTP collateral status (CS) parameters can serve as imaging biomarkers for good clinical outcomes prediction in successfull...

Background and Purpose In large vessel occlusion (LVO) stroke patients, relative cerebral blood flow (rCBF)<30% volume thresholds are commonly used in treatment decisions. In the early time window, nearly infarcted but salvageable tissue volumes may lead to pretreatment overestimates of infarct volume, and thus potentially exclude patients who may...

Although pretreatment radiographic biomarkers are well established for hemorrhagic transformation (HT) following successful mechanical thrombectomy (MT) in large vessel occlusion (LVO) strokes, they are yet to be explored for medium vessel occlusion (MeVO) acute ischemic strokes. We aim to investigate pretreatment imaging biomarkers representative...

Introduction Despite a growing emphasis on discourse processing in clinical neuroscience, relatively little is known about the neurobiology of discourse production impairments. Individuals with a history of left or right hemisphere stroke can exhibit difficulty with communicating meaningful discourse content, which implies both cerebral hemispheres...

Objective To assess pretreatment and interventional parameters as predictors of favorable Activity Measure for Post-Acute Care (AM-PAC) scores for optimal discharge planning. Design In this prospectively collected, retrospectively reviewed multicenter study from 9/1/2017 to 9/22/2022, patients were dichotomized into favorable and unfavorable AM-PA...

BACKGROUND In patients with acute ischemic stroke secondary to large vessel occlusion, achieving modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3 (excellent recanalization) over mTICI 2b is associated with improved functional outcomes. We aimed to determine pretreatment and interventional parameters that are independently associated with m...

STAIR XII (12th Stroke Treatment Academy Industry Roundtable) included a workshop to discuss the priorities for advancements in neuroimaging in the diagnostic workup of acute ischemic stroke. The workshop brought together representatives from academia, industry, and government. The participants identified 10 critical areas of priority for the advan...

Mild cognitive impairment (MCI) is clinical diagnosis that refers to individuals whose performance is below average on standardized cognitive tests, but who otherwise function independently in instrumental activities of daily living. Few prior studies have addressed the problem of selecting the optimal combination of behavioral instruments and cuto...

Purpose Quantitative mapping of brain perfusion, diffusion, T2*, and T1 has important applications in cerebrovascular diseases. At present, these sequences are performed separately. This study aims to develop a novel MRI technique to simultaneously estimate these parameters. Methods This sequence to measure perfusion, diffusion, T2*, and T1 mappin...

Perfusion images guide acute stroke management, yet few studies have been able to systematically investigate CT perfusion collected during routine care because the measures are stored in proprietary formats incompatible with conventional research analysis pipelines. We illustrate the potential of harnessing granular data from these routine scans by...

Background and aim: Acute ischemic stroke due to large vessel occlusion (AIS-LVO) is a major cause of functional dependence, an important determinant of discharge disposition. The aim of this study is to assess the utility of pretreatment and interventional parameters as predictors of favorable Activity Measure for Post Acute Care (AMPAC) scores fo...

Background: In patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO), improved functional outcomes have been reported in patients who achieve Modified Thrombolysis In Cerebral Infarction (mTICI) 2c/3 (excellent recanalization) over mTICI 2b. We aimed to determine pretreatment and interventional variables that could predi...

To extract meaningful and reproducible models of brain function from stroke images, for both clinical and research proposes, is a daunting task severely hindered by the great variability of lesion frequency and patterns. Large datasets are therefore imperative, as well as fully automated image post-processing tools to analyze them. The development...

Background: Transcranial direct current stimulation (tDCS) can be used to improve post-stroke aphasia. However, given the mixed evidence for its efficacy, individual differences may moderate the relative benefit of this strategy. In planned exploratory subgroup analyses, we examined whether age, education, sex, brain-derived neurotrophic factor st...

Frontotemporal lobar degeneration (FTLD) is one of the most common causes of early-onset dementia and presents with early social-emotional-behavioural and/or language changes that can be accompanied by a pyramidal or extrapyramidal motor disorder. About 20-25% of individuals with FTLD are estimated to carry a mutation associated with a specific FTL...

Background Distal medium vessel occlusions (DMVOs) account for a large percentage of vessel occlusions resulting in acute ischemic stroke (AIS) with disabling symptoms. We aim to assess whether pretreatment CT Perfusion collateral status (CS) parameters can serve as imaging biomarkers for good clinical outcomes prediction in successfully recanalize...

Background: Although artificial intelligence systems that diagnosis among different conditions from medical images are long term aims, specific goals for automation of human-labor, time-consuming tasks are not only feasible but equally important. Acute conditions that require quantitative metrics, such as acute ischemic strokes, can greatly benefi...

Objective: To examine changes to connectivity after aphasia treatment in the first 3 months after stroke. Methods: Twenty people experiencing aphasia within the first 3 months of stroke completed MRI before and immediately following 15 hours of language treatment. They were classified based on their response to treatment on a naming test of noun...

For the past decade, brain health has been an emerging line of scientific inquiry assessing the impact of age-related neurostructural changes on cognitive decline and recovery from brain injury. Typically, compromised brain health is attributed to the presence of small vessel disease (SVD) and brain tissue atrophy, which are represented by various...

Background and purpose: Quantitative CT perfusion (CTP) thresholds for assessing the extent of ischemia in patients with acute ischemic stroke (AIS) have been established; relative cerebral blood flow (rCBF) <30% is typically used for estimating estimated ischemic core volume and Tmax (time to maximum) >6 seconds for critical hypoperfused volume i...

Cerebrovascular disease is a leading cause of death globally. Prevention and early intervention are known to be the most effective forms of its management. Non-invasive imaging methods hold great promises for early stratification, but at present lack the sensitivity for personalized prognosis. Resting-state functional magnetic resonance imaging (rs...

Background: Understanding how brain function and language skills change during early (acute and subacute) stroke phases is critical for maximizing patient recovery, yet functional neuroimaging studies of early aphasia are scarce. In this pilot study, we used functional Near-Infrared Spectroscopy (fNIRS) to investigate how resting state functional...

Studies have shown that the integrity of white matter tracts connecting different regions in the left cerebral hemisphere is important for aphasia recovery after stroke. However, the impact of the underlying structural connection between the cortex and the cerebellum in post-stroke aphasia is poorly understood. We studied the microstructural integr...