Amir Honarmand - Academia.edu (original) (raw)

Papers by Amir Honarmand

Research paper thumbnail of Hemodynamics in bicuspid aortic valve relatives with trileaflet aortic valves compared to normal controls using 4D flow MRI

Journal of Cardiovascular Magnetic Resonance, 2014

Research paper thumbnail of Analysis of the thoracic aorta using a semi-automated post processing tool

European Journal of Radiology, 2013

To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gat... more To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gated Dual Source CT Angiogram (DSCTA). This retrospective HIPAA compliant study was approved by our IRB. Transaxial maximum diameters of outer wall to outer wall were studied in fifty patients at seven anatomic locations of the thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta (MAA) at the level of right pulmonary artery, proximal aortic arch (PROX) immediately proximal to innominate artery, distal aortic arch (DIST) immediately distal to left subclavian artery, and descending aorta (DESC) at the level of diaphragm. Measurements were performed using a manual method and semi-automated software. All readers repeated their measurements. Inter-method, intra-observer and inter-observer agreements were evaluated according to intraclass correlation coefficient (ICC) and Bland-Altman plot. The number of cases with manual contouring or center line adjustment for the semi-automated method and also the post-processing time for each method were recorded. The mean difference between semi-automated and manual methods was less than 1.3mm at all seven points. Strong inter-method, inter-observer and intra-observer agreement was recorded at all levels (ICC ≥ 0.9). The maximum rate of manual adjustment of center line and contour was at the level of annulus. The average time for manual post-processing of the aorta was 19 ± 0.3 min, while it took 8.26 ± 2.1 min to do the measurements with the semi-automated tool (Vitrea version 6.0.0.1 software). The center line was edited manually at all levels, with most corrections at the level of annulus (60%), while the contour was adjusted at all levels with highest and lowest number of corrections at the levels of annulus and DESC (75% and 0.07% of the cases), respectively. Compared to the commonly used manual method, semi-automated measurement of vessel dimensions is feasible in the thoracic aorta with the advantage of reduced post-processing time.

Research paper thumbnail of O-021 Evaluation of Baseline CT ASPECTS in Perfusion-guided Selected Patients for Intra-arterial Reperfusion Therapy

Journal of NeuroInterventional Surgery, 2013

Research paper thumbnail of P-025 Qualitative Assessment of Intra-Arterial Cone Beam CT Angiography in Precise Anatomic Localisation and Treatment Planning of Intracranial and Spinal Arteriovenous Fistulas

Journal of NeuroInterventional Surgery, 2013

Research paper thumbnail of 4D Flow MRI Indicates Changes in Intracranial Hemodynamics in Arteries Supplying Arteriovenous Malformations

PURPOSE To evaluate peak velocity (PV) and net flow (NF) in arteries supplying intracranial arter... more PURPOSE To evaluate peak velocity (PV) and net flow (NF) in arteries supplying intracranial arteriovenous malformations (AVMs) using 4D flow MRI. METHOD AND MATERIALS With IRB approval, baseline 4D flow MRI was performed at 1.5T or 3T MR systems for a prospective study. Flow quantification was performed using ECG gated three-directional velocity encoding with full 3D coverage of the AVM nidus, feeding and draining vessels, and contralateral equivalent normal arteries. 4D flow MRI was acquired in an axial oblique 3D volume using flip angle of 15°, VENC: 100 cm/s, spatial resolution = (1.2-1.6)3mm3, and temporal resolution: 44 ms. Data analysis included 3D visualization of the velocity data and flow quantification using time integrated 3D pathlines positioned orthogonal to the vessel by a commercially available software (Ensight, CEI, Inc. Apex, NC). AVM Spetzler-Martin (SM) grade and nidus volume (π/6 ·X · Y · Z dimensions) were obtained. Paired sample t test, one-way ANOVA, univaria...

Research paper thumbnail of Comparative 4D Flow MR Imaging in Quantification of Vascular Haemodynamics in Different Types of Intra-cranial Arteriovenous Malformations

Journal of Neurointerventional Surgery

Research paper thumbnail of Effect of Door-to-Antibiotic Time on Mortality of Patients with Sepsis in Emergency Department: A Prospective Cohort Study

Acta medica Iranica

Sepsis constitutes an important cause of hospital admission with a high mortality rate. Appropria... more Sepsis constitutes an important cause of hospital admission with a high mortality rate. Appropriate antibiotic therapy is the cornerstone of therapy in patients with sepsis. Although numerous studies have recommended early antibiotic initiation in severe sepsis or septic shock stages of sepsis syndrome, its role in treatment of patients with sepsis who have not entered these stages remains to be investigated. The purpose of this study is to investigate the effect of door-to-antibiotic time in sepsis patients with various degrees of severity. This is a longitudinal prospective cohort study on adult patients admitted with sepsis to the emergency department. Sepsis was defined as presence of at least two criteria of systemic inflammatory response syndrome and procalcitonin levels ≥ 2μg/l. Severity of sepsis was determined using the APACHE II (Acute Physiology and Chronic Health Evaluation II) scoring system. Time to antibiotic administration was recorded and its relationship with morta...

Research paper thumbnail of E-004 Endovascular Embolisation of Spinal Perimedullary (Type IV) Fistula Using Ethylene Vinyl Alcohol Copolymer (Onyx): Is It Safe in Children?

Journal of NeuroInterventional Surgery, 2013

Research paper thumbnail of Quantification of macro- and micro-vascular hemodynamics in cerebral arteriovenous malformations during staged embolization

Research paper thumbnail of Hemodynamic evaluation of cerebral arteriovenous malformations with combined 4D flow and perfusion MRI

Research paper thumbnail of Age-related changes in total cerebral and cardiac blood flow in children and adult volunteers from 7 months to 60 years

Research paper thumbnail of Intracranial 4D flow imaging for the quantification of age-dependent cerebral arterial inflow in children from 7 months to 18 years

Research paper thumbnail of Comprehensive hemodynamic evaluation of intracranial atherosclerotic disease with 4D flow MR imaging

Research paper thumbnail of Intracranial atherosclerotic disease: impact of regional stenotic lesions on systemic intracranial hemodynamics

Research paper thumbnail of Noninvasive assessment of hemodynamic alteration in vein of Galen aneurysmal malformations during staged embolization using 4D flow MR imaging

Research paper thumbnail of Endovascular embolization of vein of Galen aneurysmal malformations: noninvasive assessment of intracranial hemodynamic alterations with 4D flow MR imaging

Research paper thumbnail of Cerebral arterial inflow and venous outflow in pediatric patients with vein of Galen aneurysmal malformations and children controls

Research paper thumbnail of Evaluation of 4D Vascular Flow and Tissue Perfusion in Cerebral Arteriovenous Malformations: Influence of Spetzler-Martin Grade, Clinical Presentation, and AVM Risk Factors

AJNR. American journal of neuroradiology, Jan 26, 2015

The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVM... more The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVMs remains poorly understood. The purpose of this study was to assess the influence of Spetzler-Martin grade, clinical history, and risk factors on vascular flow and tissue perfusion in cerebral AVMs. 4D flow and perfusion MR imaging was performed in 17 patients with AVMs. Peak velocity and blood flow were quantified in AVM feeding and contralateral arteries, draining veins, and the straight sinus. Regional perfusion ratios (CBF, CBV, and MTT) were calculated between affected and nonaffected hemispheres. Regarding flow parameters, high-grade AVMs (Spetzler-Martin grade of >2) demonstrated significantly increased peak velocity and blood flow in the major feeding arteries (P < .001 and P = .004) and straight sinus (P = .003 and P = .012) and increased venous draining flow (P = .001). The Spetzler-Martin grade significantly correlated with cumulative feeding artery flow (r = 0.85, P &l...

Research paper thumbnail of O-014 significant acquisition dose reduction maintains diagnostic quality of biplane cerebral digital subtraction angiography

Journal of neurointerventional surgery, 2014

Digital subtraction angiography (DSA) remains the gold standard modality for evaluation, diagnosi... more Digital subtraction angiography (DSA) remains the gold standard modality for evaluation, diagnosis, and treatment planning of several intracranial vascular abnormalities. However, patient radiation dose can be considerable with both diagnostic and especially complex neurointerventional procedures. Modern biplane flat-detector angiography units provide several possibilities for automatic dose reduction by modifying X-ray tube potential, current, pulse width, and filtration thickness. We aimed to investigate the feasibility of reducing the radiation exposure dose in diagnostic DSA examinations while preserving the overall image quality for diagnostic purposes. Following IRB approval and informed consent, a prospective study was performed on patients undergoing diagnostic cerebral DSA using biplane flat detector rotational fluoroscopy and angiography unit (Artis zee/zeego, Siemens). DSA images were acquired using a predefined manufacturer standard DSA program by selecting detector dose...

Research paper thumbnail of E-043 High-Grade Dural Arteriovenous Fistula Causing Subarachnoid Haemorrhage with Direct Visualization of the Rupture Site on CT Angiography

Journal of neurointerventional surgery, 2014

We describe a case of subarachnoid haemorrhage caused by a high grade dural arteriovenous fistula... more We describe a case of subarachnoid haemorrhage caused by a high grade dural arteriovenous fistula (dAVF) with an identifiable venous rupture site on CT Angiography (CTA) in a patient with a remote history of recurrent severe dural sinus thrombosis requiring lifelong anticoagulation. The fistula was completely shut down by transarterial Onyx embolization with documented angiographic thrombosis of the downstream rupture site allowing restoration of her anticoagulation regimen. A completely independent, contralateral dAVF with isolated pial supply and cortical drainage was embolised electively. CTA has replaced conventional angiography as a first line vascular imaging study in cases of acute intracranial haemorrhage and if the imaging appearance is consistent with dAVF, a careful search should be made for a potential rupture site which may modify the treatment approach and objective. A 52-year-old right-handed female presented with sudden onset thunderclap headache, mild drowsiness. He...

Research paper thumbnail of Hemodynamics in bicuspid aortic valve relatives with trileaflet aortic valves compared to normal controls using 4D flow MRI

Journal of Cardiovascular Magnetic Resonance, 2014

Research paper thumbnail of Analysis of the thoracic aorta using a semi-automated post processing tool

European Journal of Radiology, 2013

To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gat... more To evaluates a semi-automated method for Thoracic Aortic Aneurysm (TAA) measurement using ECG-gated Dual Source CT Angiogram (DSCTA). This retrospective HIPAA compliant study was approved by our IRB. Transaxial maximum diameters of outer wall to outer wall were studied in fifty patients at seven anatomic locations of the thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta (MAA) at the level of right pulmonary artery, proximal aortic arch (PROX) immediately proximal to innominate artery, distal aortic arch (DIST) immediately distal to left subclavian artery, and descending aorta (DESC) at the level of diaphragm. Measurements were performed using a manual method and semi-automated software. All readers repeated their measurements. Inter-method, intra-observer and inter-observer agreements were evaluated according to intraclass correlation coefficient (ICC) and Bland-Altman plot. The number of cases with manual contouring or center line adjustment for the semi-automated method and also the post-processing time for each method were recorded. The mean difference between semi-automated and manual methods was less than 1.3mm at all seven points. Strong inter-method, inter-observer and intra-observer agreement was recorded at all levels (ICC ≥ 0.9). The maximum rate of manual adjustment of center line and contour was at the level of annulus. The average time for manual post-processing of the aorta was 19 ± 0.3 min, while it took 8.26 ± 2.1 min to do the measurements with the semi-automated tool (Vitrea version 6.0.0.1 software). The center line was edited manually at all levels, with most corrections at the level of annulus (60%), while the contour was adjusted at all levels with highest and lowest number of corrections at the levels of annulus and DESC (75% and 0.07% of the cases), respectively. Compared to the commonly used manual method, semi-automated measurement of vessel dimensions is feasible in the thoracic aorta with the advantage of reduced post-processing time.

Research paper thumbnail of O-021 Evaluation of Baseline CT ASPECTS in Perfusion-guided Selected Patients for Intra-arterial Reperfusion Therapy

Journal of NeuroInterventional Surgery, 2013

Research paper thumbnail of P-025 Qualitative Assessment of Intra-Arterial Cone Beam CT Angiography in Precise Anatomic Localisation and Treatment Planning of Intracranial and Spinal Arteriovenous Fistulas

Journal of NeuroInterventional Surgery, 2013

Research paper thumbnail of 4D Flow MRI Indicates Changes in Intracranial Hemodynamics in Arteries Supplying Arteriovenous Malformations

PURPOSE To evaluate peak velocity (PV) and net flow (NF) in arteries supplying intracranial arter... more PURPOSE To evaluate peak velocity (PV) and net flow (NF) in arteries supplying intracranial arteriovenous malformations (AVMs) using 4D flow MRI. METHOD AND MATERIALS With IRB approval, baseline 4D flow MRI was performed at 1.5T or 3T MR systems for a prospective study. Flow quantification was performed using ECG gated three-directional velocity encoding with full 3D coverage of the AVM nidus, feeding and draining vessels, and contralateral equivalent normal arteries. 4D flow MRI was acquired in an axial oblique 3D volume using flip angle of 15°, VENC: 100 cm/s, spatial resolution = (1.2-1.6)3mm3, and temporal resolution: 44 ms. Data analysis included 3D visualization of the velocity data and flow quantification using time integrated 3D pathlines positioned orthogonal to the vessel by a commercially available software (Ensight, CEI, Inc. Apex, NC). AVM Spetzler-Martin (SM) grade and nidus volume (π/6 ·X · Y · Z dimensions) were obtained. Paired sample t test, one-way ANOVA, univaria...

Research paper thumbnail of Comparative 4D Flow MR Imaging in Quantification of Vascular Haemodynamics in Different Types of Intra-cranial Arteriovenous Malformations

Journal of Neurointerventional Surgery

Research paper thumbnail of Effect of Door-to-Antibiotic Time on Mortality of Patients with Sepsis in Emergency Department: A Prospective Cohort Study

Acta medica Iranica

Sepsis constitutes an important cause of hospital admission with a high mortality rate. Appropria... more Sepsis constitutes an important cause of hospital admission with a high mortality rate. Appropriate antibiotic therapy is the cornerstone of therapy in patients with sepsis. Although numerous studies have recommended early antibiotic initiation in severe sepsis or septic shock stages of sepsis syndrome, its role in treatment of patients with sepsis who have not entered these stages remains to be investigated. The purpose of this study is to investigate the effect of door-to-antibiotic time in sepsis patients with various degrees of severity. This is a longitudinal prospective cohort study on adult patients admitted with sepsis to the emergency department. Sepsis was defined as presence of at least two criteria of systemic inflammatory response syndrome and procalcitonin levels ≥ 2μg/l. Severity of sepsis was determined using the APACHE II (Acute Physiology and Chronic Health Evaluation II) scoring system. Time to antibiotic administration was recorded and its relationship with morta...

Research paper thumbnail of E-004 Endovascular Embolisation of Spinal Perimedullary (Type IV) Fistula Using Ethylene Vinyl Alcohol Copolymer (Onyx): Is It Safe in Children?

Journal of NeuroInterventional Surgery, 2013

Research paper thumbnail of Quantification of macro- and micro-vascular hemodynamics in cerebral arteriovenous malformations during staged embolization

Research paper thumbnail of Hemodynamic evaluation of cerebral arteriovenous malformations with combined 4D flow and perfusion MRI

Research paper thumbnail of Age-related changes in total cerebral and cardiac blood flow in children and adult volunteers from 7 months to 60 years

Research paper thumbnail of Intracranial 4D flow imaging for the quantification of age-dependent cerebral arterial inflow in children from 7 months to 18 years

Research paper thumbnail of Comprehensive hemodynamic evaluation of intracranial atherosclerotic disease with 4D flow MR imaging

Research paper thumbnail of Intracranial atherosclerotic disease: impact of regional stenotic lesions on systemic intracranial hemodynamics

Research paper thumbnail of Noninvasive assessment of hemodynamic alteration in vein of Galen aneurysmal malformations during staged embolization using 4D flow MR imaging

Research paper thumbnail of Endovascular embolization of vein of Galen aneurysmal malformations: noninvasive assessment of intracranial hemodynamic alterations with 4D flow MR imaging

Research paper thumbnail of Cerebral arterial inflow and venous outflow in pediatric patients with vein of Galen aneurysmal malformations and children controls

Research paper thumbnail of Evaluation of 4D Vascular Flow and Tissue Perfusion in Cerebral Arteriovenous Malformations: Influence of Spetzler-Martin Grade, Clinical Presentation, and AVM Risk Factors

AJNR. American journal of neuroradiology, Jan 26, 2015

The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVM... more The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVMs remains poorly understood. The purpose of this study was to assess the influence of Spetzler-Martin grade, clinical history, and risk factors on vascular flow and tissue perfusion in cerebral AVMs. 4D flow and perfusion MR imaging was performed in 17 patients with AVMs. Peak velocity and blood flow were quantified in AVM feeding and contralateral arteries, draining veins, and the straight sinus. Regional perfusion ratios (CBF, CBV, and MTT) were calculated between affected and nonaffected hemispheres. Regarding flow parameters, high-grade AVMs (Spetzler-Martin grade of >2) demonstrated significantly increased peak velocity and blood flow in the major feeding arteries (P < .001 and P = .004) and straight sinus (P = .003 and P = .012) and increased venous draining flow (P = .001). The Spetzler-Martin grade significantly correlated with cumulative feeding artery flow (r = 0.85, P &l...

Research paper thumbnail of O-014 significant acquisition dose reduction maintains diagnostic quality of biplane cerebral digital subtraction angiography

Journal of neurointerventional surgery, 2014

Digital subtraction angiography (DSA) remains the gold standard modality for evaluation, diagnosi... more Digital subtraction angiography (DSA) remains the gold standard modality for evaluation, diagnosis, and treatment planning of several intracranial vascular abnormalities. However, patient radiation dose can be considerable with both diagnostic and especially complex neurointerventional procedures. Modern biplane flat-detector angiography units provide several possibilities for automatic dose reduction by modifying X-ray tube potential, current, pulse width, and filtration thickness. We aimed to investigate the feasibility of reducing the radiation exposure dose in diagnostic DSA examinations while preserving the overall image quality for diagnostic purposes. Following IRB approval and informed consent, a prospective study was performed on patients undergoing diagnostic cerebral DSA using biplane flat detector rotational fluoroscopy and angiography unit (Artis zee/zeego, Siemens). DSA images were acquired using a predefined manufacturer standard DSA program by selecting detector dose...

Research paper thumbnail of E-043 High-Grade Dural Arteriovenous Fistula Causing Subarachnoid Haemorrhage with Direct Visualization of the Rupture Site on CT Angiography

Journal of neurointerventional surgery, 2014

We describe a case of subarachnoid haemorrhage caused by a high grade dural arteriovenous fistula... more We describe a case of subarachnoid haemorrhage caused by a high grade dural arteriovenous fistula (dAVF) with an identifiable venous rupture site on CT Angiography (CTA) in a patient with a remote history of recurrent severe dural sinus thrombosis requiring lifelong anticoagulation. The fistula was completely shut down by transarterial Onyx embolization with documented angiographic thrombosis of the downstream rupture site allowing restoration of her anticoagulation regimen. A completely independent, contralateral dAVF with isolated pial supply and cortical drainage was embolised electively. CTA has replaced conventional angiography as a first line vascular imaging study in cases of acute intracranial haemorrhage and if the imaging appearance is consistent with dAVF, a careful search should be made for a potential rupture site which may modify the treatment approach and objective. A 52-year-old right-handed female presented with sudden onset thunderclap headache, mild drowsiness. He...