This study aimed to describe the anatomical and dimensional characteristics of carotid atherosclerosis in elderly individuals using high-resolution MRI and EBCT. 38 pairs of carotid artery segments were obtained from cadavers and imaged. The images were analyzed to measure plaque location, artery wall and lumen volumes, and estimate plaque volume. Both MRI and EBCT showed close bilateral symmetry between left and right carotid dimensions and calcium content. Plaque appeared as single lesions concentrated near the bifurcation, diminishing about 15mm distal and proximal. The measurements provide insights into carotid plaque development and potential clinical applications of non-invasive carotid imaging.
This document summarizes a study that used multicontrast MRI to classify human atherosclerotic lesions in the carotid arteries. Researchers imaged 60 patients before carotid endarterectomy and compared MRI classifications of plaque type to histological analysis. MRI correctly classified plaque types in 80.2% of cases compared to histology. The study demonstrated that high-resolution MRI can characterize intermediate to advanced plaque, which is important for longitudinal studies of plaque progression and response to treatment. Further research is still needed to improve spatial resolution and image acquisition time.
1. The document discusses several imaging techniques for atherosclerotic plaques including invasive methods like intravascular ultrasound and optical coherence tomography as well as noninvasive methods like calcium scoring and computed tomography angiography.
2. Intravascular ultrasound and optical coherence tomography provide high resolution imaging of plaque characteristics like thickness, composition, and features of vulnerable or unstable plaques through catheters inserted into arteries.
3. While invasive coronary angiography is currently the standard for diagnosing coronary artery disease, it only assesses plaque severity through luminal narrowing and does not distinguish stable from unstable plaques.
The document provides information about CT brain imaging including terminology used, differences between CT and MRI, how a CT scan works, tissue densities visualized on CT, common anatomical structures seen on brain CT, approaches to interpreting a CT brain scan, and various pathological conditions that can be identified on CT including trauma, vascular insults, infections, tumors and other disorders. Key points covered include how CT provides clear bone images while MRI better depicts soft tissue contrast, how CT reconstruction works to create cross-sectional images, and examples of some common abnormalities that manifest as hyperdense or hypodense lesions on CT scans.
Cardiac CT Angiography to detect Myocardial Bridging Han Naung Tun
CTCA is a reliable non-invasive tool for detecting myocardial bridging in coronary artery disease. [The study] found an 8.2% frequency of myocardial bridging in 219 patients with coronary artery disease who underwent CTCA. CTCA allows for visualization of the length and depth of the bridging artery and measurement of stenosis. While myocardial bridging can be clinically significant when associated with hemodynamic changes, in most cases it remains asymptomatic. CTCA is an emerging alternative to other invasive tests for diagnosing myocardial bridging.
This study compared cardiac magnetic resonance imaging (CMR) to echocardiography for assessing left ventricular non-compaction (LVNC) in 16 patients. CMR was able to analyze all heart segments, while echocardiography could only analyze 87.5% at end-diastole and 87.1% at end-systole. CMR detected a two-layered heart structure in 54% of segments compared to 42.9% for echocardiography at end-diastole and 41.4% at end-systole. Echocardiography at end-systole underestimated the ratio of non-compacted to compacted layer thickness compared to CMR and echocardi
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes that closely resemble real carotid arteries, including different stages of atherosclerotic lesions. The models are housed in holders that are compatible with MRI and allow imaging of indexed sites for reproducible measurements over time. Documentation is provided on the composition and imaging of the models to serve as standards for intra- and inter-laboratory comparisons.
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes that closely resemble real carotid arteries, including different stages of atherosclerotic lesions. The models are housed in holders that are compatible with MRI and allow indexing of reference sites. Documentation is provided on the models' composition and standardized MRI acquisition parameters to enable reproducible imaging as an internal standard over long periods.
This document summarizes a study that used multicontrast MRI to classify human atherosclerotic lesions in the carotid arteries. Researchers imaged 60 patients before carotid endarterectomy and compared MRI classifications of plaque type to histological analysis. MRI correctly classified plaque types in 80.2% of cases compared to histology. The study demonstrated that high-resolution MRI can characterize intermediate to advanced plaque, which is important for longitudinal studies of plaque progression and response to treatment. Further research is still needed to improve spatial resolution and image acquisition time.
1. The document discusses several imaging techniques for atherosclerotic plaques including invasive methods like intravascular ultrasound and optical coherence tomography as well as noninvasive methods like calcium scoring and computed tomography angiography.
2. Intravascular ultrasound and optical coherence tomography provide high resolution imaging of plaque characteristics like thickness, composition, and features of vulnerable or unstable plaques through catheters inserted into arteries.
3. While invasive coronary angiography is currently the standard for diagnosing coronary artery disease, it only assesses plaque severity through luminal narrowing and does not distinguish stable from unstable plaques.
The document provides information about CT brain imaging including terminology used, differences between CT and MRI, how a CT scan works, tissue densities visualized on CT, common anatomical structures seen on brain CT, approaches to interpreting a CT brain scan, and various pathological conditions that can be identified on CT including trauma, vascular insults, infections, tumors and other disorders. Key points covered include how CT provides clear bone images while MRI better depicts soft tissue contrast, how CT reconstruction works to create cross-sectional images, and examples of some common abnormalities that manifest as hyperdense or hypodense lesions on CT scans.
Cardiac CT Angiography to detect Myocardial Bridging Han Naung Tun
CTCA is a reliable non-invasive tool for detecting myocardial bridging in coronary artery disease. [The study] found an 8.2% frequency of myocardial bridging in 219 patients with coronary artery disease who underwent CTCA. CTCA allows for visualization of the length and depth of the bridging artery and measurement of stenosis. While myocardial bridging can be clinically significant when associated with hemodynamic changes, in most cases it remains asymptomatic. CTCA is an emerging alternative to other invasive tests for diagnosing myocardial bridging.
This study compared cardiac magnetic resonance imaging (CMR) to echocardiography for assessing left ventricular non-compaction (LVNC) in 16 patients. CMR was able to analyze all heart segments, while echocardiography could only analyze 87.5% at end-diastole and 87.1% at end-systole. CMR detected a two-layered heart structure in 54% of segments compared to 42.9% for echocardiography at end-diastole and 41.4% at end-systole. Echocardiography at end-systole underestimated the ratio of non-compacted to compacted layer thickness compared to CMR and echocardi
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes that closely resemble real carotid arteries, including different stages of atherosclerotic lesions. The models are housed in holders that are compatible with MRI and allow imaging of indexed sites for reproducible measurements over time. Documentation is provided on the composition and imaging of the models to serve as standards for intra- and inter-laboratory comparisons.
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes that closely resemble real carotid arteries, including different stages of atherosclerotic lesions. The models are housed in holders that are compatible with MRI and allow indexing of reference sites. Documentation is provided on the models' composition and standardized MRI acquisition parameters to enable reproducible imaging as an internal standard over long periods.
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes that closely resemble real carotid arteries, including different stages of atherosclerotic lesions. The models are housed in holders that are compatible with MRI and allow indexing of reference sites. Documentation is provided on the models' composition and standardized MRI acquisition parameters to enable reproducible imaging as an internal standard over long periods.
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes designed to closely resemble real carotid arteries, including gross structure, composition, and all stages of atherosclerotic lesions. The models are housed in holders compatible with MRI and have defined reference sites to allow for standardized imaging and comparison over time. Documentation is provided on the composition and imaging of the models to serve as standards for intra- and inter-laboratory quality control in multicenter trials.
Intensity Non-uniformity Correction for Image SegmentationIOSR Journals
This document discusses the application of various image segmentation techniques, including Otsu thresholding, fuzzy C-means clustering, and marker-controlled watershed segmentation, to atherosclerosis images. Atherosclerosis is the buildup of plaque in artery walls that can lead to coronary heart disease. Accurately segmenting atherosclerosis images is an important preprocessing step for analysis. The document proposes using a marker-controlled watershed segmentation algorithm to segment the images, arguing it can construct full divisions of color images while preventing oversegmentation compared to conventional watershed algorithms. It then applies several segmentation techniques to atherosclerosis images and evaluates the results.
Invasive coronary physiology to select patients for coronary revascularisation has become established in contemporary guidelines for the management of stable coronary artery disease. Compared to revascularisation based on angiography alone, the use of coronary physiology has been shown to improve clinical outcomes and cost efficiency. However, recent data from randomised controlled trials have cast doubt upon
the value of ischaemia testing to select patients for revascularisation. Importantly, 20-40% of patients have
persistence or recurrence of angina after angiographically successful percutaneous coronary intervention
(PCI). This state-of-the-art review is focused on the transitioning role of invasive coronary physiology from
its use as a dichotomous test for ischaemia with fixed cut-points, towards its utility for real-time guidance of PCI to optimise physiological results. We summarise the contemporary evidence base for ischaemia testing
in stable coronary artery disease, examine emerging indices which allow advanced physiological guidance
of PCI, and discuss the rationale and evidence base for post-PCI physiological assessments to assess the success of revascularisation.
A case of giant mediastinal liposarcoma of thymic origin a rare clinical entityDr.Debmalya Saha
Abstract
Thymoliposarcoma is an exceedingly rare tumor of thymus with a very few
cases reported till date. This case study presents a 45-year male with rare type
of thymoma. On the contrast-enhanced CT images, there was a large mass lesion
of predominantly fat attenuation in the pre-vascular compartment of the
mediastinum insinuating on both sides of the visceral compartment of the
mediastinum, and extending upto the bilateral cardio phrenic and anterior
costophrenic angles, anterior to the right ventricle with loss of fat plane with
the pericardium, with few sub-centimetric lymph nodes in the right paratracheal
and AP window and a calcified right hilar lymph node, suggestive of
well-differentiated liposarcoma/thymoliposarcoma. Initial CT guided tru-cut
tissue biopsy was inconclusive, and the repeat biopsy revealed as fibro-
collagenous tissue with area of necrosis, focal myxoid changes in the
background with presence of cells which are spindle to oval in shape with
mild nuclear pleomorphism and negative for S100, Cytokeratin, CD34, desmin.
The entire tumor was resected en masse after meticulous dissection
without the support of cardiopulmonary bypass (CPB) with an intact pericardium.
Final histopathology report of the surgical biopsy specimens is consistent
with dedifferentiated thymoliposarcoma with focal ganglionic cell differentiation.
Postoperative follow-up CECT of thorax revealed no evidence of
residual mass in the pre-vascular compartment. The patient is disease-free
and asymptomatic after 6-month and he is under routine follow-up under
Radiotherapy department since he received 30 Gy of postoperative radiotherapy
(PORT).
This document provides an overview of CT and MRI imaging in neurology. It discusses the basics of CT imaging, including orientation, planes, windows, density, slice thickness, and contrast enhancement. It also covers common CT findings such as hyperdensities, hypodensities, and ring enhancing lesions. For MRI, it outlines the basic sequences of T1, T2, FLAIR, DWI, and advanced techniques like perfusion imaging and MR spectroscopy. The document aims to explain the key concepts and findings in CT and MRI neuroimaging to help interpret scans.
In head and neck surgery, the common carotid arteries are important landmarks that help define the dissection plane. This study evaluated 46 male cadavers to examine the diameter of the carotid arteries and correlate the level of the common carotid artery (CCA) bifurcation with important anatomical landmarks. The superior border of the thyroid cartilage was found to be the most stable landmark for predicting the CCA bifurcation level. While most bifurcations occurred at the second or third cervical vertebrae, the vertebral level showed more variability between sides compared to other landmarks. This information about carotid artery anatomy can help improve surgical techniques and radiological diagnosis in the neck.
The optimal management of bifurcation lesions has received significant interest in recent years and remains a matter of debate among the
interventional cardiology community. Bifurcation lesions are encountered in approximately 21% of percutaneous coronary intervention procedures
and are associated with an increased risk of major adverse cardiac events. The Medina classification has been developed in an attempt to
standardise the terminology when describing bifurcation lesions. The focus of this article is on the management of the Medina 0,0,1 lesion
(‘Medina 001’), an uncommon lesion encountered in <5% of all bifurcations. Technical considerations, management options and interventional
techniques relating to the Medina 001 lesion are discussed. In addition, current published data supporting the various proposed interventional
treatment strategies are examined in an attempt to delineate an evidence-based approach to this uncommon lesion.
Intravascular ultrasound (IVUS) uses sound waves to visualize the inside of arteries. There are two types of IVUS systems - mechanical systems using a rotating internal cable and solid-state systems using externally mounted transducers. Both produce 360-degree images with a resolution of 100-150 μm. IVUS is used to assess plaque, vessel dimensions, stent deployment, and more. It produces cross-sectional images showing the lumen, layers of the artery wall, and plaque composition and size. Measurements include diameters, areas, plaque burden, and indices of eccentricity. IVUS helps identify vulnerable plaque and has diagnostic and interventional applications.
This document describes a method for automatically detecting and quantifying coronary artery calcifications in thoracic CT scans in order to determine cardiovascular risk. It presents challenges in analyzing non-ECG synchronized, low-dose thoracic CT scans from lung cancer screening, where the coronaries are not visible and there is noise. The method uses a coronary calcium atlas to estimate coronary locations and extract position features for calcification candidates. It was tested on 121 scans, achieving a sensitivity of 72% and 0.9 false positives per scan compared to a reference standard, with 83% agreement on cardiovascular risk categories. The results suggest automatic calcium scoring from these types of scans is feasible for estimating cardiovascular risk in lung cancer screening patients.
Epicardial fat is adipose tissue located between the heart and pericardium. It plays roles in vascular function and inflammation. Increased epicardial fat is associated with cardiovascular risk factors like obesity and metabolic syndrome. Epicardial fat can be measured using echocardiography, MRI, or CT scans to evaluate thickness, volume, or area. Greater amounts of epicardial fat correlate with worse cardiovascular health outcomes and risk factors.
This study used tagged magnetic resonance imaging (MRI) to measure left ventricular (LV) twist in different layers of the heart (endocardium, mid-wall, and epicardium) in 52 healthy subjects ranging from 21 to 82 years old. The study found that LV twist increases with age and is greatest in the endocardial layer and lowest in the epicardial layer for all age groups. Measuring LV twist using tagged MRI provides more accurate analysis compared to 2D speckle tracking echocardiography, as tagged MRI is not affected by out-of-plane motion and allows full volume analysis of the heart in 3D.
Ventricular arrhythmias can originate from complex substrates involving scar tissue. New imaging techniques like intracardiac echocardiography (ICE) and contrast-enhanced cardiac magnetic resonance (ce-CMR) can help identify these substrates and guide ablation. CE-CMR can characterize scar tissue, quantify fibrosis, and identify conduction channels within scars. ICE allows visualization of catheter position and ablation lesions. Together these techniques aim to improve ablation outcomes by enabling better identification of arrhythmogenic substrates compared to conventional mapping alone.
A talk about the future of cardiology (also medicine in general) given on the 28th april 2014 in the Medical University of Silesia in Poland to doctors and students. It shows the trends of medicine and medical technology development with the biggest potential.
Intravascular ultrasonography (IVUS) provides images of coronary arteries and other blood vessels. It plays a critical role in understanding coronary disease and guiding interventional cardiology procedures. IVUS uses a catheter-mounted ultrasound transducer to create images. It can assess plaque, guide stent placement, detect complications, and characterize lesion morphology. IVUS provides detailed information to evaluate patients and optimize interventional strategies.
The document describes histopathology results showing fluorescent microspheres adhering to atherosclerotic plaques in an Apo E mouse model after 24 hours. One macrophage was seen containing 10 fluorescent microspheres adhering to a fibrous plaque. An aggregation of 4 labeled macrophages was attached to an advanced plaque. Numerous macrophages were adhering to an isolated fatty streak comprised mainly of foam cells.
137 inflammatory cells in non ruptured atherosclerotic plaquesSHAPE Society
The document summarizes a study examining the prevalence of inflammatory cells in non-ruptured atherosclerotic plaques. The study found that moderate or heavy staining for macrophages was present in 45% of femoral artery cross-sections and 84% of femoral arteries had at least one cross-section with moderate or heavy inflammation. Additionally, there was no relationship found between the degree of inflammation in the left versus right coronary artery within individuals. The conclusion is that the presence of inflammatory cells is common in non-ruptured plaques and the level of local inflammation does not predict inflammation in other arteries.
This study investigated genetic differences in vascular remodeling and shear stress regulation in response to altered blood flow in four inbred rat strains. The results showed significant differences among strains in their ability to maintain normal endothelial shear stress levels through outward arterial remodeling when flow was increased or decreased. Specifically, the GH strain was better able to regulate shear stress through remodeling compared to the SHR-SP strain. These genetic differences in vascular responses to changes in blood flow have important implications for understanding the variable manifestations of atherosclerosis and susceptibility to cardiovascular disease in individuals and populations. Future studies are needed to investigate whether similar genetic differences exist in humans and their role in clinical outcomes.
C. pneumoniae infection of human aortic endothelial cells leads to increased expression of the cell adhesion molecule ICAM-1. The study found that C. pneumoniae activates the PKC and NF-κB signaling pathways in endothelial cells, resulting in increased transcription of the ICAM-1 gene. Inhibition of either PKC or NF-κB blocked the C. pneumoniae-induced upregulation of ICAM-1. The increased ICAM-1 expression contributes to the chronic inflammation associated with atherosclerosis by promoting adhesion and transmigration of monocytes into the arterial wall.
This document provides background on Jacques Barth, an expert in cardiovascular imaging and risk assessment. It discusses the evolution of ultrasound technology for measuring intima-media thickness (IMT) from 1986 to 2005. IMT is an early marker of atherosclerosis and cardiovascular risk. The document also addresses issues around vulnerable plaques, reporting IMT measurements, and assessing cardiovascular risk in children and adolescents.
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes that closely resemble real carotid arteries, including different stages of atherosclerotic lesions. The models are housed in holders that are compatible with MRI and allow indexing of reference sites. Documentation is provided on the models' composition and standardized MRI acquisition parameters to enable reproducible imaging as an internal standard over long periods.
This document describes models of human carotid arteries that can be used for quality control in clinical trials evaluating atherosclerotic lesions with MRI endpoints. The models are made from cadaveric human carotid arteries and have attributes designed to closely resemble real carotid arteries, including gross structure, composition, and all stages of atherosclerotic lesions. The models are housed in holders compatible with MRI and have defined reference sites to allow for standardized imaging and comparison over time. Documentation is provided on the composition and imaging of the models to serve as standards for intra- and inter-laboratory quality control in multicenter trials.
Intensity Non-uniformity Correction for Image SegmentationIOSR Journals
This document discusses the application of various image segmentation techniques, including Otsu thresholding, fuzzy C-means clustering, and marker-controlled watershed segmentation, to atherosclerosis images. Atherosclerosis is the buildup of plaque in artery walls that can lead to coronary heart disease. Accurately segmenting atherosclerosis images is an important preprocessing step for analysis. The document proposes using a marker-controlled watershed segmentation algorithm to segment the images, arguing it can construct full divisions of color images while preventing oversegmentation compared to conventional watershed algorithms. It then applies several segmentation techniques to atherosclerosis images and evaluates the results.
Invasive coronary physiology to select patients for coronary revascularisation has become established in contemporary guidelines for the management of stable coronary artery disease. Compared to revascularisation based on angiography alone, the use of coronary physiology has been shown to improve clinical outcomes and cost efficiency. However, recent data from randomised controlled trials have cast doubt upon
the value of ischaemia testing to select patients for revascularisation. Importantly, 20-40% of patients have
persistence or recurrence of angina after angiographically successful percutaneous coronary intervention
(PCI). This state-of-the-art review is focused on the transitioning role of invasive coronary physiology from
its use as a dichotomous test for ischaemia with fixed cut-points, towards its utility for real-time guidance of PCI to optimise physiological results. We summarise the contemporary evidence base for ischaemia testing
in stable coronary artery disease, examine emerging indices which allow advanced physiological guidance
of PCI, and discuss the rationale and evidence base for post-PCI physiological assessments to assess the success of revascularisation.
A case of giant mediastinal liposarcoma of thymic origin a rare clinical entityDr.Debmalya Saha
Abstract
Thymoliposarcoma is an exceedingly rare tumor of thymus with a very few
cases reported till date. This case study presents a 45-year male with rare type
of thymoma. On the contrast-enhanced CT images, there was a large mass lesion
of predominantly fat attenuation in the pre-vascular compartment of the
mediastinum insinuating on both sides of the visceral compartment of the
mediastinum, and extending upto the bilateral cardio phrenic and anterior
costophrenic angles, anterior to the right ventricle with loss of fat plane with
the pericardium, with few sub-centimetric lymph nodes in the right paratracheal
and AP window and a calcified right hilar lymph node, suggestive of
well-differentiated liposarcoma/thymoliposarcoma. Initial CT guided tru-cut
tissue biopsy was inconclusive, and the repeat biopsy revealed as fibro-
collagenous tissue with area of necrosis, focal myxoid changes in the
background with presence of cells which are spindle to oval in shape with
mild nuclear pleomorphism and negative for S100, Cytokeratin, CD34, desmin.
The entire tumor was resected en masse after meticulous dissection
without the support of cardiopulmonary bypass (CPB) with an intact pericardium.
Final histopathology report of the surgical biopsy specimens is consistent
with dedifferentiated thymoliposarcoma with focal ganglionic cell differentiation.
Postoperative follow-up CECT of thorax revealed no evidence of
residual mass in the pre-vascular compartment. The patient is disease-free
and asymptomatic after 6-month and he is under routine follow-up under
Radiotherapy department since he received 30 Gy of postoperative radiotherapy
(PORT).
This document provides an overview of CT and MRI imaging in neurology. It discusses the basics of CT imaging, including orientation, planes, windows, density, slice thickness, and contrast enhancement. It also covers common CT findings such as hyperdensities, hypodensities, and ring enhancing lesions. For MRI, it outlines the basic sequences of T1, T2, FLAIR, DWI, and advanced techniques like perfusion imaging and MR spectroscopy. The document aims to explain the key concepts and findings in CT and MRI neuroimaging to help interpret scans.
In head and neck surgery, the common carotid arteries are important landmarks that help define the dissection plane. This study evaluated 46 male cadavers to examine the diameter of the carotid arteries and correlate the level of the common carotid artery (CCA) bifurcation with important anatomical landmarks. The superior border of the thyroid cartilage was found to be the most stable landmark for predicting the CCA bifurcation level. While most bifurcations occurred at the second or third cervical vertebrae, the vertebral level showed more variability between sides compared to other landmarks. This information about carotid artery anatomy can help improve surgical techniques and radiological diagnosis in the neck.
The optimal management of bifurcation lesions has received significant interest in recent years and remains a matter of debate among the
interventional cardiology community. Bifurcation lesions are encountered in approximately 21% of percutaneous coronary intervention procedures
and are associated with an increased risk of major adverse cardiac events. The Medina classification has been developed in an attempt to
standardise the terminology when describing bifurcation lesions. The focus of this article is on the management of the Medina 0,0,1 lesion
(‘Medina 001’), an uncommon lesion encountered in <5% of all bifurcations. Technical considerations, management options and interventional
techniques relating to the Medina 001 lesion are discussed. In addition, current published data supporting the various proposed interventional
treatment strategies are examined in an attempt to delineate an evidence-based approach to this uncommon lesion.
Intravascular ultrasound (IVUS) uses sound waves to visualize the inside of arteries. There are two types of IVUS systems - mechanical systems using a rotating internal cable and solid-state systems using externally mounted transducers. Both produce 360-degree images with a resolution of 100-150 μm. IVUS is used to assess plaque, vessel dimensions, stent deployment, and more. It produces cross-sectional images showing the lumen, layers of the artery wall, and plaque composition and size. Measurements include diameters, areas, plaque burden, and indices of eccentricity. IVUS helps identify vulnerable plaque and has diagnostic and interventional applications.
This document describes a method for automatically detecting and quantifying coronary artery calcifications in thoracic CT scans in order to determine cardiovascular risk. It presents challenges in analyzing non-ECG synchronized, low-dose thoracic CT scans from lung cancer screening, where the coronaries are not visible and there is noise. The method uses a coronary calcium atlas to estimate coronary locations and extract position features for calcification candidates. It was tested on 121 scans, achieving a sensitivity of 72% and 0.9 false positives per scan compared to a reference standard, with 83% agreement on cardiovascular risk categories. The results suggest automatic calcium scoring from these types of scans is feasible for estimating cardiovascular risk in lung cancer screening patients.
Epicardial fat is adipose tissue located between the heart and pericardium. It plays roles in vascular function and inflammation. Increased epicardial fat is associated with cardiovascular risk factors like obesity and metabolic syndrome. Epicardial fat can be measured using echocardiography, MRI, or CT scans to evaluate thickness, volume, or area. Greater amounts of epicardial fat correlate with worse cardiovascular health outcomes and risk factors.
This study used tagged magnetic resonance imaging (MRI) to measure left ventricular (LV) twist in different layers of the heart (endocardium, mid-wall, and epicardium) in 52 healthy subjects ranging from 21 to 82 years old. The study found that LV twist increases with age and is greatest in the endocardial layer and lowest in the epicardial layer for all age groups. Measuring LV twist using tagged MRI provides more accurate analysis compared to 2D speckle tracking echocardiography, as tagged MRI is not affected by out-of-plane motion and allows full volume analysis of the heart in 3D.
Ventricular arrhythmias can originate from complex substrates involving scar tissue. New imaging techniques like intracardiac echocardiography (ICE) and contrast-enhanced cardiac magnetic resonance (ce-CMR) can help identify these substrates and guide ablation. CE-CMR can characterize scar tissue, quantify fibrosis, and identify conduction channels within scars. ICE allows visualization of catheter position and ablation lesions. Together these techniques aim to improve ablation outcomes by enabling better identification of arrhythmogenic substrates compared to conventional mapping alone.
A talk about the future of cardiology (also medicine in general) given on the 28th april 2014 in the Medical University of Silesia in Poland to doctors and students. It shows the trends of medicine and medical technology development with the biggest potential.
Intravascular ultrasonography (IVUS) provides images of coronary arteries and other blood vessels. It plays a critical role in understanding coronary disease and guiding interventional cardiology procedures. IVUS uses a catheter-mounted ultrasound transducer to create images. It can assess plaque, guide stent placement, detect complications, and characterize lesion morphology. IVUS provides detailed information to evaluate patients and optimize interventional strategies.
The document describes histopathology results showing fluorescent microspheres adhering to atherosclerotic plaques in an Apo E mouse model after 24 hours. One macrophage was seen containing 10 fluorescent microspheres adhering to a fibrous plaque. An aggregation of 4 labeled macrophages was attached to an advanced plaque. Numerous macrophages were adhering to an isolated fatty streak comprised mainly of foam cells.
137 inflammatory cells in non ruptured atherosclerotic plaquesSHAPE Society
The document summarizes a study examining the prevalence of inflammatory cells in non-ruptured atherosclerotic plaques. The study found that moderate or heavy staining for macrophages was present in 45% of femoral artery cross-sections and 84% of femoral arteries had at least one cross-section with moderate or heavy inflammation. Additionally, there was no relationship found between the degree of inflammation in the left versus right coronary artery within individuals. The conclusion is that the presence of inflammatory cells is common in non-ruptured plaques and the level of local inflammation does not predict inflammation in other arteries.
This study investigated genetic differences in vascular remodeling and shear stress regulation in response to altered blood flow in four inbred rat strains. The results showed significant differences among strains in their ability to maintain normal endothelial shear stress levels through outward arterial remodeling when flow was increased or decreased. Specifically, the GH strain was better able to regulate shear stress through remodeling compared to the SHR-SP strain. These genetic differences in vascular responses to changes in blood flow have important implications for understanding the variable manifestations of atherosclerosis and susceptibility to cardiovascular disease in individuals and populations. Future studies are needed to investigate whether similar genetic differences exist in humans and their role in clinical outcomes.
C. pneumoniae infection of human aortic endothelial cells leads to increased expression of the cell adhesion molecule ICAM-1. The study found that C. pneumoniae activates the PKC and NF-κB signaling pathways in endothelial cells, resulting in increased transcription of the ICAM-1 gene. Inhibition of either PKC or NF-κB blocked the C. pneumoniae-induced upregulation of ICAM-1. The increased ICAM-1 expression contributes to the chronic inflammation associated with atherosclerosis by promoting adhesion and transmigration of monocytes into the arterial wall.
This document provides background on Jacques Barth, an expert in cardiovascular imaging and risk assessment. It discusses the evolution of ultrasound technology for measuring intima-media thickness (IMT) from 1986 to 2005. IMT is an early marker of atherosclerosis and cardiovascular risk. The document also addresses issues around vulnerable plaques, reporting IMT measurements, and assessing cardiovascular risk in children and adolescents.
The document discusses the role of lipoproteins, particularly LDL and HDL, in inflammation and atherosclerosis. LDL readily enters the artery wall where it can become modified, making it proinflammatory. Modified LDL stimulates expression of MCP-1, which recruits monocytes. Modified LDL also promotes differentiation of monocytes into macrophages. In contrast, HDL is potentially anti-inflammatory. Atherosclerosis is characterized as an inflammatory disease where lipoproteins influence multiple aspects of inflammation.
The document discusses research into using MRI with fibrin-targeted gadolinium contrast agents to detect vulnerable plaques associated with heart attacks, presenting findings that this approach can successfully identify fibrin deposits in thrombi in animal studies and has potential for sensitive detection of injured plaques in humans; it also notes the need for more studies to develop highly sensitive targeted contrast agents for multiple imaging modalities to identify vulnerable plaque features beyond structure.
This document describes a study that uses intravascular ultrasound (IVUS), biplane coronary angiography, and blood flow measurements to characterize endothelial shear stress (ESS) in coronary arteries. It found that over 6 months, areas of low ESS demonstrated plaque progression, areas of normal ESS remained stable, and areas of high ESS developed outward remodeling. The technology allows in vivo determination of intracoronary flow velocity and ESS, which has not previously been possible. This provides a method to predict progression of atherosclerosis and vascular remodeling. A pilot study applied this technique in 8 patients at baseline and 6 months to analyze changes in native coronary artery disease and in-stent restenosis while taking candesartan vs fel
The document describes a new mouse model called "AtheroReversa mice" that allows researchers to reverse hypercholesterolemia and atherosclerosis without drugs or diet changes. The mice lack the LDL receptor and ApoB genes but have a conditional Mttp gene that produces MTP. Injecting the mice with pI-pC activates Cre recombinase which inactivates Mttp in the liver, eliminating LDL cholesterol production and preventing atherosclerosis. This new model could help analyze regression of existing atherosclerotic plaques.
This progress report discusses ongoing near-infrared (NIR) spectroscopy studies. It notes that a new probe design is being developed to improve signal detection in the NIR range. Characterization of a new light source and additional tissue phantom studies are needed. The report identifies ongoing difficulties with depth penetration studies and experimental setup issues. Priorities include analyzing existing data to inform probe redesign, characterizing the new light source, conducting depth penetration and tissue phantom studies, and addressing experimental setup challenges.
3rd vulnerable plaque rumberg 3 16-02 2SHAPE Society
Coronary artery calcium detected by electron beam tomography (EBT) establishes a diagnosis of coronary atherosclerosis, as there are no false positive calcium measurements. The amount of calcium seen on EBT correlates directly with the actual amount of coronary plaque measured by intravascular ultrasound and histopathology. Studies have also shown that a higher coronary artery calcium score on EBT is associated with greater risk of future myocardial infarction, sudden cardiac death, or ischemia over follow-up periods of 3-6 years.
151 performance of a localized fiber opticSHAPE Society
This document describes the design and testing of a fiber optic probe to measure metabolic markers in human carotid plaque tissue samples in vitro. The probe was designed to interrogate a small volume of tissue (~1 mm3) and measure tissue lactate concentration and pH. Human plaque samples were collected and studied in a controlled in vitro setup to validate experimental stability over time. Optical absorption spectra were collected from plaque samples and related to reference measurements of lactate concentration and pH through multivariate calibration models, achieving accurate predictions. The fiber optic probe design and in vitro experimental methods were able to precisely measure metabolic markers for characterization of plaque vulnerability.
The document discusses a study conducted by the Department of Cardiology at Athens Medical School in 2001 that used a new aortic thermography catheter to measure temperatures in the aorta and coronary sinus of patients. The study involved 18 patients with documented coronary artery disease and 12 patients with normal coronary arteries, as determined by angiography. The purpose was to investigate if there are temperature differences in blood between the coronary sinus and right atrium in patients with left coronary artery lesions compared to those without.
1. MRI uses spatial encoding gradients and radiofrequency pulses to selectively excite slices of tissue and encode spatial information in the MRI signal. 2. Frequency encoding gradients encode left-right spatial information, while phase encoding gradients are applied in the orthogonal direction to fully spatially encode each image slice. 3. Fourier transformation is used to reconstruct images from the spatially encoded MRI data.
035 respiratory infection of apo e ko miceSHAPE Society
1) Acute respiratory infection caused by influenza virus led to excessive plaque inflammation in the aortas of ApoE knockout mice, implicating acute infection in triggering acute coronary events.
2) Influenza infection increased plaque inflammation and macrophage infiltration in the mice with or without plaque rupture/erosion.
3) Further examination of infected mice tissue found polymorphic inflammatory cell infiltrates associated with platelets and fibrin near the plaques, indicating proinflammatory and procoagulant effects of acute influenza infection.
This document proposes a non-invasive method using SPIO (super paramagnetic iron oxide) nanoparticles to image macrophage infiltration and inflammation in vulnerable atherosclerotic plaques. Rabbits and mice were injected with SPIO, which accumulated in inflamed plaque areas correlated with macrophage density. SPIO-enhanced MRI then successfully identified these inflamed plaques non-invasively in vivo. This technique could provide a way to detect rupture-prone plaques and better understand plaque vulnerability.
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This document discusses different definitions of arterial remodeling used in post-mortem and intravascular ultrasound research. It notes that the various definitions lead to large variations in reported prevalence numbers for expansive, intermediate, and constrictive remodeling. The definitions are analyzed and some are noted to only be suitable for certain study types. It concludes that careful consideration of the remodeling definition used is needed when reporting prevalences, as without a gold standard or serial studies, the reference sites may not be free of atherosclerotic disease and could themselves be remodeled.
The document discusses several factors that are considered predictors of plaque vulnerability, including luminal narrowing, plaque volume and composition, fibrous cap thickness, and plaque inflammation. It reviews studies that show myocardial infarction can develop from previously non-severe lesions and that lipid content, cap thickness, inflammation, and stress factors like circumferential stress are correlated with plaque stability and vulnerability. In conclusion, the size and composition of the lipid core, thickness and composition of the fibrous cap, and inflammation are well-established predictors of plaque rupture.
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Optical coherence tomography (OCT) provides high-resolution cross-sectional images of tissue structures on the micron scale in situ and in real time. It uses near-infrared light instead of sound like IVUS. OCT images are generated by measuring the echo time delay and intensity of light reflected or backscattered from internal structures using interferometry techniques. OCT can characterize atherosclerotic plaque composition and identify thin fibrous caps. Studies have shown OCT can detect plaque rupture and intracoronary thrombus with higher accuracy than IVUS or angiography.
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Advances in CT technology allow for higher resolution imaging with multi-slice CT scanners. This provides benefits for visualizing complex anatomy, diseases, and evaluating vasculature non-invasively with techniques like CT angiography. Additional applications enabled by high resolution volumetric data include virtual bronchoscopy and colonoscopy which provide endoluminal views to evaluate airways and the colon with benefits over conventional scopes. While CT involves ionizing radiation, doses are addressed with new technologies and some procedures may replace more invasive options, proving new CT applications are of increasing clinical value.
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This document describes a study that uses intravascular ultrasound (IVUS), biplane coronary angiography, and blood flow measurements to characterize endothelial shear stress (ESS) in coronary arteries. It found that over 6 months, areas of low ESS demonstrated plaque progression, areas of normal ESS remained stable, and areas of high ESS developed outward remodeling. The technology allows in vivo determination of intracoronary flow velocity and ESS, which has not previously been possible. This provides a method to predict progression of atherosclerosis and vascular remodeling. A pilot study applied this technique in 8 patients at baseline and 6 months to analyze changes in native coronary arteries and in-stent restenosis with antihypertensive treatments.
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This document summarizes a study that developed a new methodology for measuring endothelial shear stress (ESS) in coronary arteries in vivo. The methodology uses intravascular ultrasound, biplane angiography, and computational fluid dynamics to reconstruct coronary arteries in 3D and model blood flow/ESS. A pilot study applied this to 8 patients, finding areas of low ESS demonstrated plaque progression over 6 months while areas of normal ESS were stable. The technology may help predict disease progression and response to interventions based on local ESS environments.
Digital subtraction angiography (DSA) provides high quality images of cerebral vasculature and remains the gold standard. It involves injecting iodinated contrast into arteries and digitally subtracting pre-and post-contrast images to visualize vessels. Modern DSA uses flat panel detectors for higher resolution and lower radiation. It allows 3D reconstruction of vessel anatomy and is useful for diagnosing and treating conditions like aneurysms and AVMs. While very accurate for vessels, DSA cannot simultaneously image bone which CT angiography can provide.
The document summarizes a study that measured the internal and external diameters of major arteries in cadavers ranging from 59 to 99 years old. A significant positive correlation was found between the external diameter of the right common carotid artery and age of death. Surprisingly, no correlations were found between the diameters of the aortic arch, femoral arteries, and age of death. This may provide insight for circulatory procedures or indicate a genetic predisposition to higher vascular blood flow, allowing some to live longer.
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Digital subtraction angiography (DSA) is the gold standard for evaluating the cerebral vasculature. It involves injecting iodinated contrast material into arteries and using subtraction techniques to visualize vessels. The normal anatomy includes the circle of Willis and branches of major arteries. Variants are common. DSA is used to diagnose conditions like aneurysms and arteriovenous malformations. Newer digital systems provide 3D reconstruction and lower radiation exposure compared to older techniques. DSA remains an important tool for interventional procedures and treatment planning of complex vascular lesions.
Digital subtraction angiography (DSA) is the gold standard for evaluating the cerebral vasculature. It involves injecting iodinated contrast material into arteries and using subtraction techniques to visualize vessels. The normal anatomy includes the circle of Willis and branches of major arteries. Variants are common. DSA is used to diagnose conditions like aneurysms and arteriovenous malformations. Newer digital systems provide 3D reconstruction and less radiation exposure compared to older techniques. DSA remains an important tool for interventional procedures and treatment planning of complex vascular lesions of the brain.
Digital subtraction angiography (DSA) is the gold standard for evaluating the cerebral vasculature. It involves injecting iodinated contrast material into arteries and using subtraction techniques to visualize vessel anatomy. The circle of Willis and its major branches including the anterior, middle, and posterior cerebral arteries are described. Variants of vessel anatomy are common. DSA allows diagnosis of conditions like aneurysms and arteriovenous malformations. While newer techniques like CT and MR angiography are available, DSA remains the standard due to its ability to clearly depict complex vascular lesions for treatment planning.
Takayasu arteritis is a chronic inflammatory disease that primarily affects large arteries like the aorta and its branches. Accurate early diagnosis is important to improve outcomes for patients. Imaging like CT angiography and MR angiography are essential non-invasive tools to detect luminal narrowing, wall thickening, and other vascular abnormalities associated with Takayasu arteritis. Differential diagnosis includes other diseases like atherosclerosis and giant cell arteritis that can present similarly on imaging. Characteristic findings on CT and MR imaging can help establish the diagnosis of Takayasu arteritis.
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This document provides an overview of reviewing basic chest x-rays. It begins with introducing the systematic checklist approach of reviewing the patient name, position, and technical quality before proceeding to other areas. The checklist then guides reviewing soft tissues, skeletal structures, abdomen, neck, spine, rib cage, mediastinum, and lungs in a sequential order. Key anatomical structures are defined including lobes, heart, mediastinum, hilum, and ribs. Common techniques, densities, and pathological findings are also reviewed to aid in chest x-ray interpretation.
Characteristics of coronary artery ectasia and its association with carotid i...Premier Publishers
This study was conducted to uncover the relation between coronary artery ectasia (CAE) and markers of atherosclerosis. A total of 1611 coronary angiograms were prospectively examined to find out patients with CAE. Those patients were divided into 2 groups: Mixed CAE with stenotic coronary artery disease (CAD) “group 1” and pure CAE “group 2”. Two control groups of age-adjusted subjects were selected consecutively in a 1:1 fashion; one with normal coronaries “group 3” (Pure CAE: normal coronaries) and the other with obstructive CAD only “group 4” (Mixed CAE: obstructive CAD). All recruited subjects underwent carotid intima-media thickness (IMT) and high sensitivity C-reactive protein (hs-CRP) level measurements. Out of examined angiograms, 35 subjects showed mixed CAE “group 1” and 26 showed pure CAE “group 2”. Age and gender-adjusted logistic regression analysis model revealed that significant independent predictors for CAE were: hypertension, smoking, absence of DM and hs-CRP level > 3 mg/L. Mean carotid IMT was significantly higher in group 2 than group 3 and in group 4 than group 1 (1±0.1 versus 0.4±0.2 mm and 1.4±0.4 versus 1±0.2 mm respectively, P < 0.001 for both). Mean hs-CRP level was significantly higher in group 1 than group 4 and in group 2 than group 3 (7±2 versus 3±0.8 mg/L and 6±2 versus 1±0.6 mg/L respectively, P < 0.001 for both). We concluded that atherosclerosis may not be the only plausible explanation for CAE.
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This document outlines an approach to identifying and managing coronary risk. It recommends that prevention must be the primary goal through intensive global risk factor reduction for all patients with clinically apparent heart disease. It also recommends identifying asymptomatic high-risk individuals through testing like the Framingham Risk Score so they can receive prevention. It proposes a risk stratification approach from low to very high risk based on annual risk levels and corresponding testing and treatments, with very high risk patients receiving the most intensive treatments like invasive detection of unstable plaques and procedures like CABG or multiple drug-eluting stents.
Zahi A. Fayad is an Associate Professor who studies molecular imaging of atherosclerosis using MRI. His research focuses on developing targeted contrast agents to noninvasively detect unstable plaque. Some agents under investigation include annexin A5 labeled with a radioisotope to detect apoptosis, FDG-PET to assess plaque activity, and fibrin-targeted and MMP-targeting Gd-based contrasts. Additional work involves lipid-based particulate agents using reconstituted HDL or iron oxide nanoparticles. The goal is to improve MRI detection sensitivity and specificity for high-risk plaque characterization.
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This document discusses the use of coronary CT angiography (CTA) to detect and characterize coronary atherosclerosis beyond just detecting coronary stenoses. CTA can identify calcified plaques, non-calcified plaques, and mixed plaques. It can detect atheromas and characterize plaque density. CTA can also identify intracoronary thrombi and myocardial infarction scars. The document outlines the CTA scanning parameters and techniques used to minimize motion artifacts and optimize image quality for plaque detection and characterization.
This document describes a study that introduces a non-invasive method for imaging macrophage infiltration in inflamed atherosclerotic plaques using superparamagnetic iron oxide (SPIO) nanoparticles and MRI. The researchers injected SPIO into hypercholesterolemic and normal rabbits and found that SPIO profoundly accumulated in areas of macrophage infiltration in the atherosclerotic plaques, as confirmed by histology. SPIO-enhanced MRI was able to identify these inflamed plaques non-invasively. The results suggest SPIO-enhanced MRI can be a novel method for detecting rupture-prone inflamed plaques associated with heart attacks and strokes.
This document discusses a novel tracer for MRI imaging of macrophage infiltration in atherosclerotic plaque. It summarizes research into lipid-coated superparamagnetic iron oxide nanoparticles (SPIOs) that are phagocytosed by macrophages. The researchers tested various SPIO coatings and sizes to maximize macrophage uptake while minimizing oxidative stress. Lipid-coated SPIOs combined with certain aminoglycans showed the highest uptake and lowest induction of reactive oxygen species. The goal is to develop an MRI contrast agent that can noninvasively image vulnerable, inflamed plaques by detecting macrophage presence.
This document discusses the use of DNA microarrays in vulnerable plaque research. It provides background on atherosclerosis and identifies DNA microarrays as a tool that can be used to investigate the molecular mechanisms underlying plaque vulnerability. The document outlines the basic steps of a DNA microarray experiment and discusses considerations for experimental design, data analysis, and validation of results. It also summarizes several studies that have used DNA microarrays or related techniques to examine gene expression in atherosclerosis.
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This document discusses approaches to identifying and managing coronary risk. It states that the primary goal should be preventing acute cardiac events through intensive risk factor reduction for all patients with clinically apparent heart disease. Additionally, it notes that one third of sudden cardiac deaths and heart attacks occur in previously asymptomatic individuals with undiagnosed risk factors or pre-clinical disease. The document proposes identifying high-risk asymptomatic individuals through testing to provide prevention. It presents a risk stratification approach using testing like CRP, cholesterol, glucose and imaging to guide different levels of risk factor reduction and management.
This document discusses the use of DNA microarrays in studying vulnerable atherosclerotic plaques. It provides background on atherosclerosis and plaque rupture. DNA microarrays allow high-throughput analysis of gene and protein expression, which can provide insights into molecular mechanisms underlying plaque vulnerability. One study used microarrays to analyze gene expression differences between ruptured and stable plaques, identifying perilipin as upregulated in ruptured plaques. However, microarray analysis of atherosclerosis is still in its early stages with many technical challenges to address.
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The document presents findings on the A20 gene, which encodes a zinc finger protein that inhibits NF-kB activity and TNF-induced apoptosis. The study found that C57 and FVB mouse strains have a coding difference in A20 that generates a phosphorylation site in C57 mice. C57-A20 was less effective at shutting down TNF-induced NF-kB activity and C57 cells were less susceptible to TNF-induced apoptosis compared to FVB cells. This suggests less active A20 in C57 mice leads to increased inflammation and reduced apoptosis, while more active A20 in FVB mice decreases inflammation and increases apoptosis, contributing to differences in atherosclerosis susceptibility between the strains.
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130 mri assessment of human atherosclerotic disease
1. Anatomical Basis for MRI Assessment
of Human Atherosclerotic Disease:
MRI Dimensions of Post-Mortem
Carotid Artery Pairs from 38 Elderly
Individuals
W. Insull Jr., G. J. Adams,
C. B. Bordelon Jr., J. D. Morrisett
Baylor College of Medicine, Houston TX
Contact Info: William Insull Jr., M.D. winsull@bcm.tmc.edu
Joel D. Morrisett, Ph.D. morriset@bcm.tmc.edu
2. Abstract
Carotid artery atherosclerosis is a significant cause of strokes and can be
evaluated non-invasively by MRI. The purpose of this study was to determine
by MRI and EBCT the anatomical pathology of atherosclerosis in elderly
individuals most likely to have fullest expression of atherosclerosis. Pairs of
carotid artery segments around the bifurcation were obtained from 38
individuals in the anatomical laboratory after pressure perfusion fixation. They
were examined by high resolution MRI using a 1.5T clinical MR system
equipped with a phased array coil and by clinical EBCT. We measured the
location of the atherosclerotic plaque along the artery, the volumes of the artery
wall and lumen, and estimated the plaque volume. The replicate variation for
intra- and interscan volumes (coefficients of variation) measured the minimum
variances for the clinical MRI scan procedure excluding patient-dependent
sources of variance. Both MRI and EBCT showed close bilateral symmetry of
lesions for dimensions and calcium content, respectively. Carotid plaques
appeared to be single lesions with maximum development at the bifurcation
diminishing progressively to terminate about 15 mm distal and proximal to the
bifurcation. We identified the implications of these anatomical observations for
the concepts of development of atherosclerosis in single carotid lesions and
noted potential clinical applications.
3. Background
• Carotid atherosclerosis provides a potentially fruitful site for the study of
atherosclerosis development, diagnosis, and treatment.
• The carotid artery bifurcation is highly susceptible to atherosclerosis.
• The growth and development of carotid lesions is unlimited throughout all ages since
lesion size is not restricted by the limits of anatomical geometry of the artery.
• Advanced lesions of carotid atherosclerosis occur in populations with high prevalence
of atherosclerosis, stages IV to VII by the AHA classification 1995.
• All earlier stages of atherosclerotic lesions occur simultaneously with the most
advanced lesions, generally distributed radially and sequentially directly adjacent to
and contiguous to these most advanced lesions.
• The microscopic pathological characteristics of carotid atherosclerosis are similar to
atherosclerosis at other clinically significant arterial sites, coronary arteries,
peripheral arteries and aorta.
• Inter-individual variation in extent of carotid AS is broad within and among
populations, similar to wide variance for coronary and aortic disease.
• The symmetrical pairing of carotid arteries provides an opportunity to evaluate the
variance of atherosclerosis lesions between similar sites within each individual.
• Carotid arteries are readily accessible to non-invasive imaging by a variety of
techniques, including B mode ultrasound, computed tomography and magnetic
resonance imaging.
4. Purpose
Sample Acquisition:
• Cadaveric carotid arteries
were used as the model.
• Fifty perfusion-fixed
carotid pairs were excised
from human cadavers
aged 74±13 (48-98) years.
• Of the 50 sample pairs, 38
contained the entire
plaque and were suitable
for rigorous analysis.
3D Reconstruction of a
Carotid Artery from
multiple 3mm thick MRI
slices.
Cadaveric Carotid Artery
Specimen
To describe the anatomical, pathological, and dimensional
characteristics of carotid atherosclerosis in elderly individuals
using high resolution MRI 1.5T and EBCT.
5. Cadaveric Carotid Arteries
Useful properties of the cadaveric carotid artery samples:
a) Tissue was pressure perfusion fixed before excision, which
preserves the tissue and maintains in vivo geometry.
b) Most of the periadventitial tissue has been removed, which
reduces specimen bulk while retaining essential anatomical
features.
CCA
BIF
ICA
ECA
Single Cadaveric Carotid Artery Sample
The common carotid
artery (CCA), bifurcation
(BIF), external carotid
artery (ECA), and
internal carotid artery
(ICA) are clearly seen.
6. Properties of Cadaveric Carotid Arteries
Essential properties of the cadaveric carotid artery samples:
• Contain all three layers of the arterial wall (intima, media,
adventitia), and some perivascular soft tissue.
• Contain a range of lesion types.
• Give reproducible images over >1 year.
• Provide stable reference for:
• intra-laboratory standardization
• inter-laboratory standardization for multicenter clinical
trials
Other useful attributes:
• Enables comparison of left and right carotids from an
individual.
• Can be analyzed using independent techniques other than
MRI (e.g. histology, µCT, FTIR spectroscopy).
7. Imaging Protocol
Samples in EBCT Scanner
Ex Vivo Imaging Apparatus 1.5T GE Clinical MRI Scanner
An Imatron EBCT scanner and AccuImage
software were used to obtain calcification
scores for each sample.
A 1.5T GE Horizon LX clinical MRI
equipped with Pathway phased array coils
was used to acquire PDW, T1W, and T2W
images with an in-plane spatial resolution of
0.195 mm and a slice thickness of 3mm.
8. Carotid Artery Volume Quantitation using MRI
Measurement Algorithm:
• A semiautomatic active contour algorithm was used
to define the boundaries of the lumen and the outer
wall of the artery.
• The generalized gradient vector field force was used
as the external force for the active contour algorithm.
• The area of each contour was measured and
multiplied by the slice thickness to obtain the volume.
T2W MRI Image
Internal Lumen
External Lumen
Artery Wall
1. Initial Contours 2. Final Contours 3. Measurements
9. Plaque Volume Estimation and Assumptions
Estimation:
• Estimate normal wall thickness as the average minimum wall thickness within
each branch of the carotid tree.
• Estimate normal wall volume by sweeping a thickness contour around the
outer wall.
• Plaque Volume = Total Wall Volume – Normal Wall Volume.
• Percent Stenosis = Plaque Volume / Estimated Normal Lumen.
Assumptions:
• A normal, non-diseased wall is represented by the wall with the minimal
thickness.
• Normal wall thickness remains constant around the artery wall.
• Normal wall thickness remains the same within each branch of the carotid.
Internal Lumen
External Lumen
Artery Wall
2. Measurements1. T2W MRI Image
Normal Wall
Plaque
3. Plaque Estimate
10. Comparison of Volumes within Artery Pairs
Computation and Comparison of Aggregate Volumes:
• For comparison purposes, slices were indexed by their distance from the
bifurcation.
• The bifurcation was defined as the first MRI slice in which both the internal
and external lumen were visible as two separate orifices.
• Aggregate volumes for nine contiguous slices bounding the bifurcation were
computed for each sample.
1. Locate Bifurcation 2. Align Slices by Offset 3. Compute Volumes
MRI of
Left
Carotid
Artery
MRI of
Right
Carotid
Artery
Slice 10
Slice 11
Offset 0 on Left
Offset 0 on Right
Left Aggregate Volume
Right Aggregate Volume
11. Multiple Contrast Imaging
PDW
T1W
T2W
Contiguous
3mm thick
MRI slices.
I/E2 I/E1 Bifurc. C1 C2
• Tissues were imaged using multiple contrast weightings, including proton density,
T1, and T2-weightings.
• The different weightings provide differential contrast among principal tissue
components (e.g. necrotic core, fibrous cap, calcification, thrombus) within the
atherosclerotic plaque.
• Cai et al. have demonstrated that it is possible to differentiate between different
tissue types using multi-contrast MR imaging in vivo.
13. Carotid Volume Distributions
Slice volume averages were computed for slices at the same
offset in the left and right carotid arteries for the 38 pairs.
Average Left
Slice Volumes at
Offset 0
Sample 1 Offset 0 Left
+
Sample 2 Offset 0 Left
Average Right
Slice Volumes at
Offset 0
Sample 1 Offset 0 Right
+
Sample 2 Offset 0 Right
= =vs.
14. 0
20
40
60
80
100
120
140
160
C10 C8 C6 C4 C2 B I2/E2 I4/E4 I6/E6
Slice
Volume(mm
3
)
Common
Internal
External
Lumen Volume Distributions
in the Left and Right Carotids
Slice volume profiles measured using the semiautomated active contour algorithm. Distance
between slices is 3mm.
Dotted lines are left carotid volumes.
Solid lines are right carotid volumes.
15. 0
50
100
150
200
250
300
350
400
C10 C8 C6 C4 C2 B I2/E2 I4/E4 I6/E6
Slice
Volume(mm
3
)
Common
Internal
External
Total Artery Volume Distributions
in the Left and Right Carotids
Slice volume profiles measured using the semiautomated active contour algorithm. Distance
between slices is 3mm.
Dotted lines are left carotid volumes.
Solid lines are right carotid volumes.
16. 0
50
100
150
200
250
C10 C8 C6 C4 C2 B I2/E2 I4/E4 I6/E6
Slice
Volume(mm
3
)
Common
Internal
External
Total Wall Volume Distributions
in the Left and Right Carotids
Total wall slice volume profiles calculated as total artery volume minus lumen volume.
Distance between slices is 3mm.
Dotted lines are left carotid volumes.
Solid lines are right carotid volumes.
17. 0
20
40
60
80
100
120
140
C10 C8 C6 C4 C2 B I2/E2 I4/E4 I6/E6
Slice
Volume(mm
3
)
Common
Internal
External
Normal Wall Volume Distributions
in the Left and Right Carotids
Slice volume profiles estimated using the automated plaque estimation algorithm. Distance
between slices is 3mm.
Dotted lines are left carotid volumes.
Solid lines are right carotid volumes.
18. 0
10
20
30
40
50
60
70
80
C10 C8 C6 C4 C2 B I2/E2 I4/E4 I6/E6
Slice
Volume(mm
3
)
Common
Internal
External
Dotted lines are left carotid volumes.
Solid lines are right carotid volumes.
Plaque Volume Distributions
in the Left and Right Carotids
Slice volume profiles estimated using the automated plaque estimation algorithm. Distance
between slices is 3mm. Plaque volume is concentrated near the bifurcation, with 80% of the
plaque within 9mm of the bifurcation in the internal carotid, 12 mm within the external
carotid, and 18mm in the common carotid.
19. 0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
C10 C8 C6 C4 C2 B I2/E2 I4/E4 I6/E6
Slice
Volume(mm
3
)
Common
Internal
(Circles)
External
(Triangles)
Percent Stenosis Distributions
in the Left and Right Carotids
Slice volume profiles estimated using the automated plaque estimation algorithm. Distance
between slices is 3mm. Percent stenosis was calculated by dividing the estimated plaque
volume by the estimated original lumen.
Dotted lines are left carotid volumes.
Solid lines are right carotid volumes.
20. Wall Thickness Distributions
• Wall thickness distributions were calculated for each MR slice
in the carotid artery.
• Averages for each branch were computed by taking the mean
of the average wall thickness of each slice within that branch.
• Maximums for each branch were computed by finding the
largest maximum wall thickness for each slice within that
branch.
Maximum
Wall
Thickness
21. Scatter Plots of the Average and Max Wall Thickness
in mm. of the Internal, External and Common
Carotid Artery Branches from MRI
0 1 2 3
0
1
2
3
Left Internal
RightInternal
0 1 2 3
0
1
2
3
Left External
RightExternal
0 1 2 3
0
1
2
3
Left Common
RightCommon
r=0.63r=0.75r=0.48
0.0 2.5 5.0 7.5 10.0
0.0
2.5
5.0
7.5
10.0
Left Common
RightCommon
0.0 2.5 5.0 7.5
0.0
2.5
5.0
7.5
Left Internal
RightInternal
0.0 2.5 5.0 7.5
0.0
2.5
5.0
7.5
Left External
RightExternal
r=0.57r=0.23 r=0.52
Average Wall Thicknesses
Maximum Wall Thicknesses
22. Scatter Plots of the
Average Wall Thickness v. the Maximum Wall Thickness
in mm. of the Internal, External and Common
Carotid Artery Branches from MRI
0 1 2 3
0.0
2.5
5.0
7.5
Left Internal Avg
LeftInternalMax
0 1 2 3
0.0
2.5
5.0
7.5
Right Internal Avg
RightInternalMax
0 1 2 3
0
1
2
3
4
5
Left External Avg
LeftExternalMax
0 1 2 3
0.0
2.5
5.0
7.5
Right External Avg
RightExternalMax
0 1 2 3
0.0
2.5
5.0
7.5
10.0
Left Common Avg
LeftCommonMax
0 1 2 3
0.0
2.5
5.0
7.5
10.0
Right Common Avg
RightCommonMax
r=0.73
r=0.85
r=0.74
r=0.71
r=0.79
r=0.53
23. Aggregate Volumes Statistics
Aggregate volumes were computed for nine contiguous slices
bounding the bifurcation for each sample in the 38 pairs.
vs.
Left Aggregate Volume Right Aggregate Volume
24. 0 500 1000 1500 2000
0
500
1000
1500
2000
Left Lumen
RightLumen
Scatter Plots of Carotid Artery
Aggregate Volumes from MRI
0 1000 2000 3000 4000
0
1000
2000
3000
4000
5000
Left Total Artery
RightTotalArtery
0 1000 2000 3000
0
1000
2000
3000
Left Total Wall
RightTotalWall0 500 1000 1500 2000
0
500
1000
1500
2000
Left Normal Wall
RightNormalWall
0 500 1000 1500
0
500
1000
1500
Left Plaque
RightPlaque
0 25 50 75
0
25
50
75
Left Percent Stenosis
RightPercentStenosis
25. Average Carotid Artery Aggregate Volumes from MRI
0
500
1000
1500
2000
2500
3000
3500
Left
Lumen
Volume
Right
Lumen
Volume
Left Total
Artery
Volume
Right Total
Artery
Volume
Left Total
Wall
Volume
Right Total
Wall
Volume
Left
Normal
Wall
Volume
Right
Normal
Wall
Volume
Left
Plaque
Volume
Right
Plaque
Volume
• Average volumes in mm3 for left and right carotid volumes from MRI.
• None of the left v. right volumes were significantly different.
• Error bars are standard deviations.
26. Scatter Plots of Carotid Artery Calcium Volume Scores
from EBCT
0 500 1000 1500 2000
0
500
1000
1500
2000
Left Calcium Volume Score
RightCalciumVolumeScore
0 1000 2000 3000
0
1000
2000
3000
Left Agatston Score
RightAgatstonScore
• Two separate scores were computed from the same images.
• The Agatston Score is calculated based on calcification area times a scale factor.
• The Volume Score uses the isotropic interpolation to calculate the volume of
calcification.
• The two calcification scores are highly correlated with one another (r=0.997).
• The scores are not normally distributed within the population of individuals.
27. Average Carotid Artery Calcification Scores from EBCT
Two separate scores were computed from the same images. The Agatston Score is calculated
based on calcification area times a scale factor, whereas the Volume Score uses the isotropic
interpolation to calculate the volume of calcification.
Left and Right Carotid Artery EBCT Calcification Scores
from 38 Sample Pairs
Error Bars are Standard Deviations
Agatston Score Volume Score
-200
0
200
400
600
800
1000
Left Agatston
Score
Right Agatston
Score
Left Calcium
Volume Score
Right Calcium
Volume Score
28. Left v. Right Carotid Volume (MRI) and
Agatston Score (EBCT) Concordance Correlations
• Lin’s concordance correlation coefficients of left and right carotid volumes
from MR and left and right calcification scores from EBCT.
• Lin’s concordance correlation coefficient measures the agreement between a
pair of variables.
• Error bars are 95% confidence intervals.
0.54
0.63
0.71
0.64
0.58
0.51
0.95 0.94
0.0
0.2
0.4
0.6
0.8
1.0
Lumen
Volume
Total Artery
Volume
Total Wall
Volume
Normal
Wall
Volume
Plaque
Volume
Percent
Stenosis
Agatston
Score
Volume
Score
ConcordanceCorrelationCoefficient
29. Correlations between Agatston Score (EBCT) and
Aggregate Volumes (MRI)
Correlations of Agatston Score vs Aggregate Volumes (N=76)
Error Bars are 95% Confidence Intervals
-0.17
0.27
0.50 0.46 0.44
0.53
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
Lumen
Volume
Total Artery
Volume
Total Wall
Volume
Normal Wall
Volume
Plaque
Volume
Percent
Stenosis
Aggregate Volume
CorrelationCoefficient
30. Reproducibility Statistics
• To test the reproducibility of MRI imaging of the models, two image sets,
consisting of two full acquisitions (PDW, T1W, T2W) on four models, were
acquired.
• Between the two sets the holder was removed from the magnet, the coils were
removed from the holder, and the temperature of the water bath was re-
equilibrated.
• Arterial volumes of each model were quantified using the semiautomated
algorithm.
• The reproducibility of the measured volumes from the different models is
quantified using the coefficient of variation (mean±SD), which is expressed as a
percentage.
Lumen Total Wall Normal Wall Plaque
Within Sets
COV (N=8)
0.33±0.24 0.70±0.30 1.01±1.11 2.48±2.14
Between Sets
COV (N=4)
2.19±2.00 2.63±1.75 3.96±2.16 4.47±1.56
31. Summary of Results
The anatomical characteristics of the carotid plaques have been described by the
average values of the study subjects:
• Carotid plaque is a single continuous lesion extending from the common carotid into
the internal and external branches, without evidence of discontinuities of structure
that indicate multiple plaques at the carotid site.
• Lesions are located at the region of the bifurcation, presumably in the area of the
carotid bulb, within 15mm proximally and distally from the flow divider. Lesions’
longitudinal development within the artery wall appears to be equal along the
common carotid and the internal and external branches.
• Lesion bulk is greater in the internal carotid that in the internal carotid. Volumes
within the external carotid are 30 to 50% smaller per slice.
• The sum of the plaque volumes in the internal and external carotid in the slice most
proximal to the bifurcation is equal to the plaque volume in the common carotid slice
most proximal to the bifurcation.
• The maximum volume of plaque is at the region of the bifurcation. This is probably
the region with the most advanced plaque.
• Proximal and distal to the region of maximal development, the volume per slice
decreases rapidly in a curvilinear fashion.
32. Discussion of Results
1. Studying elderly patients has the inherent advantage of studying individuals with
the fullest development of atherosclerosis due to prolonged exposure to all risk
factors. The development of carotid atherosclerosis, raised lesions to the naked
eye, is progressive with age and in high risk populations is a companied by
increasing occurrence of complicated and calcified lesions. Solberg et al
2. The analysis of variance of MRI measurements of a single cadaveric carotid artery
provides an estimate of the minimum variance achievable with the MRI scan
procedure alone. This procedure excludes all sources of variance related to
patients, as within scan movements, and interscan differences of positioning and
movement. This provides as basis for systematic analysis of variance of MRI
clinical scans that are essential for estimating sample sizes for studies of treatment
effects on the dimensions of the plaque volume.
3. The comparison of pairs of carotids within individual patients shows the strong
bilateral symmetry of the disease. This supports the use of analysis of a single
artery as an estimate of the burden of atherosclerosis among similar arteries. It also
starts to define the inter-arterial variance of atherosclerosis within an individual,
the least difference as it occurs between bilaterally symmetrical arteries.
33. Discussion of Results
The analysis provides measurements on the development of atherosclerosis within a
single plaque. The results support the following statements:
• The plaque region with the greatest volume, at the carotid bifurcation, probably has
the plaques most advanced stage of development, and are probably the oldest
region of the plaque.
• The plaque regions with the smallest detectable volumes, at the proximal and distal
edges of the plaque, probably have the earliest stage of development, and are the
youngest region of the plaque.
• Since plaques appear to grow centrifugally along radial vectors, similar young
regions probably occur at the lateral edges of the plaque.
• These observations support the concept of the plaques’ centrifugal growth and
development along radii from the initial site.
• Whether the grades of lesions described by the AHA classification are arranged
along the radial vectors of growth requires further study.
34. Discussion of Results
The analysis of the anatomical dimensions of carotid plaques from MRI images has
substantial implications for clinical use of MRI:
• Diagnosis of atherosclerosis by detection of arterial lesions.
• Staging of the development of carotid atherosclerosis. Staging procedures require
initially the quantitative measurements of the lesion location and the lesions’
physical dimensions. While plaques’ degree of surface involvement surface, and
compositional heterogeneity have been used customarily for staging plaque
development, the volume of the plaque can now be used to further define the stage
of development.
• Rationale for selection of therapy based on the characteristics of the plaque, it’s
location, dimensions and composition.
• Monitoring therapy developing criteria for significant therapeutic effect, as
reduction in plaque volume.
• Adjusting therapy if treatment effects are not satisfactory
• Guidance to endarterectomy surgeon for dissection to excise lesions.
35. References and Acknowledgements
References
• Adams GJ, Simoni DM, Bordelon
CB, et al. Stroke. 2002;33:2575-
2580.
• Cai J-M, Hatsukami TS, Ferguson
MS, et al. Circulation.
2002;106:1368-1373.
• Karmonik C, Eldrige C, Vick GW, et
al. Am J Cardiol. 2001;88:78E.
• Solberg LA, McGarry PA, Moossy J,
et al. Ann N Y Acad Sci.
1968;149:956-973.
• Stary HC, Chandler AB, Dinsmore
RE, et al. Circulation.
1995;92:1355-1374.
• Zarins CK, Giddens DP, Bharadvaj
BK, et al. Circ. Res. 1983;53:502-
514.
Acknowledgements
• Funding was provided by grants to Dr.
Morrisett from the Welch Foundation
(Q1325) and the National Heart, Lung
and Blood Institute of the NIH
(HL07812 and HL63090.
• Gareth Adams was supported in part by
a training fellowship from the Keck
Center for Computational and Structural
Biology of the Gulf Coast Consortia
(NLM 5T5LM07093).
• EBCT calcification scoring was
performed by Darlene Simoni, RT.