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Papers by Mohammed A Almekhlafi
Journal of NeuroInterventional Surgery, 2016
Intravenous tissue plasminogen activator has limited efficacy in fibrinolysis of large proximal i... more Intravenous tissue plasminogen activator has limited efficacy in fibrinolysis of large proximal intracranial thrombi. Thus, recent endovascular acute stroke trials restricted their selection criteria to patients with proximal occlusions in the anterior circulation. Although the terminal internal carotid artery occlusion is relatively easy to identify, there is often a debate as to what constitutes a proximal (involving the M1 segment) versus a distal (involving the M2 segment and beyond) middle cerebral artery occlusion. In light of overwhelming evidence demonstrating superiority of endovascular treatment in patients with proximal occlusion, this distinction has significant practical implications in patient selection. Here we present a brief review of the proximal (M1) segment of the middle cerebral artery anatomy and provide practical methods to recognize and separate the M1 and M2 segments. In keeping with the belief that CT angiography (CTA) (preferably multiphase CTA) is the ideal screening test for patients with emergent large vessel occlusion, we have provided tips for expeditious and accurate vascular imaging interpretation.
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Radiology, Jan 29, 2015
Purpose To describe the use of an imaging selection tool, multiphase computed tomographic (CT) an... more Purpose To describe the use of an imaging selection tool, multiphase computed tomographic (CT) angiography, in patients with acute ischemic stroke (AIS) and to demonstrate its interrater reliability and ability to help determine clinical outcome. Materials and Methods The local ethics board approved this study. Data are from the pilot phase of PRoveIT, a prospective observational study analyzing utility of multimodal imaging in the triage of patients with AIS. Patients underwent baseline unenhanced CT, single-phase CT angiography of the head and neck, multiphase CT angiography, and perfusion CT. Multiphase CT angiography generates time-resolved images of pial arteries. Pial arterial filling was scored on a six-point ordinal scale, and interrater reliability was tested. Clinical outcomes included a 50% or greater decrease in National Institutes of Health Stroke Scale (NIHSS) over 24 hours and 90-day modified Rankin Scale (mRS) score of 0-2. The ability to predict clinical outcomes was compared between single-phase CT angiography, multiphase CT angiography, and perfusion CT by using receiver operating curve analysis, Akaike information criterion (AIC), and Bayesian information criterion (BIC). Results A total of 147 patients were included. Interrater reliability for multiphase CT angiography is excellent (n = 30, κ = 0.81, P < .001). At receiver operating characteristic curve analysis, the ability to predict clinical outcome is modest (C statistic = 0.56, 95% confidence interval [CI]: 0.52, 0.63 for ≥50% decrease in NIHSS over 24 hours; C statistic = 0.6, 95% CI: 0.53, 0.68 for 90-day mRS score of 0-2) but better than that of models using single-phase CT angiography and perfusion CT (P < .05 overall). With AIC and BIC, models that use multiphase CT angiography are better than models that use single-phase CT angiography and perfusion CT for a decrease of 50% or more in NIHSS over 24 hours (AIC = 166, BIC = 171.7; values were lowest for multiphase CT angiography) and a 90-day mRS score of 0-2 (AIC = 132.1, BIC = 137.4; values were lowest for multiphase CT angiography). Conclusion Multiphase CT angiography is a reliable tool for imaging selection in patients with AIS. (©) RSNA, 2015 Online supplemental material is available for this article.
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The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
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Stroke
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Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2015
BackgroundWe have theorized that clots with stasis are longer. We therefore explored the relation... more BackgroundWe have theorized that clots with stasis are longer. We therefore explored the relationship between thrombus imaging characteristics on noncontrast computed tomography (NCCT) and magnetic resonance imaging (MRI) with clot length and pial collaterals on baseline computed tomography angiography (CTA).MethodsProspective study of acute ischemic stroke patients (2005-2009) from Keimyung University. Patients with known stroke symptom onset time, baseline CTA, MRI, and with M1-Middle Cerebral Artery (MCA)±intracranial internal carotid artery (ICA) occlusions were included. Clot length and pial collaterals were measured on baseline CTA.ResultsA total of 104 patients (mean age 65.1±12.28 years, 56.7% male, median baseline National Institutes of Health Stroke Scale 13) with intracranial ICA + MCA (n=50) or isolated M1-MCA (n=54) occlusions were included. Hyperdense sign on NCCT had a median clot length of 42.3 mm versus 29.5 mm when hyperdense negative (p=0.02). Clots showing bloomi...
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International Journal of Stroke
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Annals of Saudi medicine
The epidemiology, clinical characteristics, and risk factors of aneurysmal subarachnoid hemorrhag... more The epidemiology, clinical characteristics, and risk factors of aneurysmal subarachnoid hemorrhage (aSAH) in Saudi Arabia are still largely unknown. This retrospective cohort study was aimed to determine these features of the disease. A retrospective cohort review was performed on all patients with aSAH who were treated and followed at King Abdulaziz University Hospital between July 2000 and December 2013. A quantitative methodology was used and data were collected on patients' age, gender, nationality, time to hospital presentation, clinical presentation, aneurysm characteristics, treatment, complications, and outcome. A total of 41 patients with aSAH were included with a mean age of 43.2 (11.5) years; and males comprised 34.1%. Smoking and hypertension were the most common risk factors. Eight patients had known risk factors for aSAH, and were diagnosed using CT scans. An unfavorable outcome was associated with the pres.ence of vasospasm (P < .001), cerebral edema (P=.001), ...
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ABSTRACT Dural arteriovenous fistulas (dAVFs) are unusual vascular lesions that may form because ... more ABSTRACT Dural arteriovenous fistulas (dAVFs) are unusual vascular lesions that may form because of trauma or sinus thrombosis, but are idiopathic in most cases [1]. Connections between the dural artery and the cortical veins result in the veins being exposed to high pressures, leading to venous hypertension and subarachnoid hemorrhage [2]. Patients may present with pulsatile tinnitus (or pulse-synchronous cephalic bruit), non-specific headaches, vision loss or mental status change [3]. One or several major arteries can supply a dAVF, including the vertebral, basilar, and external (ECA) or internal carotid arteries (ICA) through their dural branches [2]. Given the high risk of bleeding in dAVFs with cortical venous hypertension, treatment of such lesions is indicated. This can be achieved via endovascular occlusion of the fistulous pouch or via open microsurgical disconnection.
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Journal of NeuroInterventional Surgery, 2016
Intravenous tissue plasminogen activator has limited efficacy in fibrinolysis of large proximal i... more Intravenous tissue plasminogen activator has limited efficacy in fibrinolysis of large proximal intracranial thrombi. Thus, recent endovascular acute stroke trials restricted their selection criteria to patients with proximal occlusions in the anterior circulation. Although the terminal internal carotid artery occlusion is relatively easy to identify, there is often a debate as to what constitutes a proximal (involving the M1 segment) versus a distal (involving the M2 segment and beyond) middle cerebral artery occlusion. In light of overwhelming evidence demonstrating superiority of endovascular treatment in patients with proximal occlusion, this distinction has significant practical implications in patient selection. Here we present a brief review of the proximal (M1) segment of the middle cerebral artery anatomy and provide practical methods to recognize and separate the M1 and M2 segments. In keeping with the belief that CT angiography (CTA) (preferably multiphase CTA) is the ideal screening test for patients with emergent large vessel occlusion, we have provided tips for expeditious and accurate vascular imaging interpretation.
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Radiology, Jan 29, 2015
Purpose To describe the use of an imaging selection tool, multiphase computed tomographic (CT) an... more Purpose To describe the use of an imaging selection tool, multiphase computed tomographic (CT) angiography, in patients with acute ischemic stroke (AIS) and to demonstrate its interrater reliability and ability to help determine clinical outcome. Materials and Methods The local ethics board approved this study. Data are from the pilot phase of PRoveIT, a prospective observational study analyzing utility of multimodal imaging in the triage of patients with AIS. Patients underwent baseline unenhanced CT, single-phase CT angiography of the head and neck, multiphase CT angiography, and perfusion CT. Multiphase CT angiography generates time-resolved images of pial arteries. Pial arterial filling was scored on a six-point ordinal scale, and interrater reliability was tested. Clinical outcomes included a 50% or greater decrease in National Institutes of Health Stroke Scale (NIHSS) over 24 hours and 90-day modified Rankin Scale (mRS) score of 0-2. The ability to predict clinical outcomes was compared between single-phase CT angiography, multiphase CT angiography, and perfusion CT by using receiver operating curve analysis, Akaike information criterion (AIC), and Bayesian information criterion (BIC). Results A total of 147 patients were included. Interrater reliability for multiphase CT angiography is excellent (n = 30, κ = 0.81, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). At receiver operating characteristic curve analysis, the ability to predict clinical outcome is modest (C statistic = 0.56, 95% confidence interval [CI]: 0.52, 0.63 for ≥50% decrease in NIHSS over 24 hours; C statistic = 0.6, 95% CI: 0.53, 0.68 for 90-day mRS score of 0-2) but better than that of models using single-phase CT angiography and perfusion CT (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05 overall). With AIC and BIC, models that use multiphase CT angiography are better than models that use single-phase CT angiography and perfusion CT for a decrease of 50% or more in NIHSS over 24 hours (AIC = 166, BIC = 171.7; values were lowest for multiphase CT angiography) and a 90-day mRS score of 0-2 (AIC = 132.1, BIC = 137.4; values were lowest for multiphase CT angiography). Conclusion Multiphase CT angiography is a reliable tool for imaging selection in patients with AIS. (©) RSNA, 2015 Online supplemental material is available for this article.
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The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques
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Stroke
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Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 2015
BackgroundWe have theorized that clots with stasis are longer. We therefore explored the relation... more BackgroundWe have theorized that clots with stasis are longer. We therefore explored the relationship between thrombus imaging characteristics on noncontrast computed tomography (NCCT) and magnetic resonance imaging (MRI) with clot length and pial collaterals on baseline computed tomography angiography (CTA).MethodsProspective study of acute ischemic stroke patients (2005-2009) from Keimyung University. Patients with known stroke symptom onset time, baseline CTA, MRI, and with M1-Middle Cerebral Artery (MCA)±intracranial internal carotid artery (ICA) occlusions were included. Clot length and pial collaterals were measured on baseline CTA.ResultsA total of 104 patients (mean age 65.1±12.28 years, 56.7% male, median baseline National Institutes of Health Stroke Scale 13) with intracranial ICA + MCA (n=50) or isolated M1-MCA (n=54) occlusions were included. Hyperdense sign on NCCT had a median clot length of 42.3 mm versus 29.5 mm when hyperdense negative (p=0.02). Clots showing bloomi...
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International Journal of Stroke
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Annals of Saudi medicine
The epidemiology, clinical characteristics, and risk factors of aneurysmal subarachnoid hemorrhag... more The epidemiology, clinical characteristics, and risk factors of aneurysmal subarachnoid hemorrhage (aSAH) in Saudi Arabia are still largely unknown. This retrospective cohort study was aimed to determine these features of the disease. A retrospective cohort review was performed on all patients with aSAH who were treated and followed at King Abdulaziz University Hospital between July 2000 and December 2013. A quantitative methodology was used and data were collected on patients' age, gender, nationality, time to hospital presentation, clinical presentation, aneurysm characteristics, treatment, complications, and outcome. A total of 41 patients with aSAH were included with a mean age of 43.2 (11.5) years; and males comprised 34.1%. Smoking and hypertension were the most common risk factors. Eight patients had known risk factors for aSAH, and were diagnosed using CT scans. An unfavorable outcome was associated with the pres.ence of vasospasm (P < .001), cerebral edema (P=.001), ...
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ABSTRACT Dural arteriovenous fistulas (dAVFs) are unusual vascular lesions that may form because ... more ABSTRACT Dural arteriovenous fistulas (dAVFs) are unusual vascular lesions that may form because of trauma or sinus thrombosis, but are idiopathic in most cases [1]. Connections between the dural artery and the cortical veins result in the veins being exposed to high pressures, leading to venous hypertension and subarachnoid hemorrhage [2]. Patients may present with pulsatile tinnitus (or pulse-synchronous cephalic bruit), non-specific headaches, vision loss or mental status change [3]. One or several major arteries can supply a dAVF, including the vertebral, basilar, and external (ECA) or internal carotid arteries (ICA) through their dural branches [2]. Given the high risk of bleeding in dAVFs with cortical venous hypertension, treatment of such lesions is indicated. This can be achieved via endovascular occlusion of the fistulous pouch or via open microsurgical disconnection.
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