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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atherogenesis is known to be associated with the stresses that act on or within the arterial wall. Still, the uneven distribution of atherosclerotic lesions and the impact of vessel remodeling on disease progression are poorly understood. A methodology is proposed to study the correlations between fluid dynamic parameters and histological markers of atherosclerosis. Trends suggested by preliminary data from four patients with advanced carotid bifurcation arterial disease are examined and compared to hypotheses in the literature. Four patients were scanned using MRI and ultrasound, and subsequently underwent carotid endarterectomy. For each patient. a geometric model and a numerical mesh were constructed from MR data, and velocity boundary conditions established. Computations yield values for average wall shear stress (WSS), maximum wall shear stress temporal gradient (WSSTG), and Oscillatory Shear Index (OSI). Following surgery, the excised plaques were sectioned, stained for smooth muscle cells (SMC), macrophages (M phi), lipid (LIP), and collagen (COL), and analyzed quantitatively. Correlations attempted between the various fluid dynamic variables and the biological markers were interesting but inconclusive. Tendencies of WSSTG and WSS to correlate negatively with M phi and LIP, and positively with COL and SMC, as well as tendencies of OSI to correlate positively with Mphi and LIP and negatively with COL and SMC, were observed. These trends agree with hypotheses in the literature, which are based on ex vivo and in vitro experimental studies.
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PMID:Characterization of the atherosclerotic carotid bifurcation using MRI, finite element modeling, and histology. 1529 31

High-resolution, non-invasive imaging methods are required to monitor progression and regression of atherosclerotic plaques. We investigated the use of MRI to measure changes in plaque volume and vessel remodelling during progression and regression of atherosclerosis in New Zealand White rabbits. Atherosclerotic lesions were induced in the abdominal aorta by balloon injury and cholesterol feeding. MR images (2D) of the abdominal aorta were acquired with cardiac and respiratory gating using a fast spin echo sequence with and without fat-suppression. In an initial study on rabbits treated for 30 weeks we imaged the aortae with a spatial resolution of 250x250 micrometers with a slice thickness of 2 mm and achieved a close correlation between MRI-derived measurements and those made on perfusion pressure-fixed histological sections (r(1) = 0.83, slope p(1) < 0.01). We subsequently imaged 18 rabbits before and periodically during 12 weeks of cholesterol feeding (progression) followed by 12 weeks on normal diet (regression). Aortic wall (atherosclerotic lesion) volume increased significantly during progression and decreased during regression. In contrast, lumen volume increased during progression and did not change during regression. In conclusion, this study confirms that non-invasive, high-resolution MRI can be used to monitor progression and regression of atherosclerosis, each within 3 months and shows, for the first time in a short-term model, that positive remodelling occurs early during progression and persists through regression of atherosclerotic lesions.
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PMID:Short term arterial remodelling in the aortae of cholesterol fed New Zealand white rabbits shown in vivo by high-resolution magnetic resonance imaging - implications for human pathology. 1544 52

A 62-year-old man with diabetes mellitus, hypertension, and hyperlipidemia was admitted to our hospital because of sudden onset of left chest pain. He was diagnosed with unstable angina with left heart failure and underwent intra-aortic balloon pumping (IABP) immediately. On the 3rd day after removal of the IABP (7th hospital day), he developed sudden paraplegia with pain. Spinal MRI on the 12th hospital day revealed a spinal swelling (Th11-L2). He was died of cardiac shock on the 19th hospital day. Autopsy examination of the spinal cord revealed a large infarct from the lower thoracic segment to the sacral segment. Microscopic examination of these areas disclosed occlusive emboli most frequently of the anterior spinal arteries including posterior spinal arteries. These emboli were found in two different forms, one consisting of new cholesterol emboli and the other of old atheromatous emboli. On autopsy, the aorta exhibited severe atherosclerosis with multiple ulcerative plaques, and there was infarction of the spleen. In our case, spinal cord infarction was caused by a massive amount of cholesterol crystals from the aorta related to IABP.
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PMID:[Spinal cord infarction due to cholesterol emboli complicating intra-aortic balloon pumping (case report and review of the literature)]. 1551 3

Paramedian pontine infarct (PPI) is usually attributed to basilar artery (BA) atherosclerosis. However, this hypothesis has thus far been supported only by post-mortem studies. The authors show that high-resolution MRI is a promising method that can detect BA plaques in patients with PPI at or near the origin of the penetrating artery, whereas MR angiograms may appear normal.
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PMID:High-resolution MRI identifies basilar artery plaques in paramedian pontine infarct. 1569 95

We report a 39-year-old woman who presented with only dizziness and vertigo for 2 months. Neurological examination revealed no abnormalities except for hypereflexia on the left side extremities. Neurootological examination revealed no abnormalities. MRI of the brain demonstrated patchy hyperintensity areas on FLAIR images in the periventricular white matter and external capsule. Her grandmother had cerebral infarction and her father is suffering from multi-infarct dementia. Her second older sister who similarly had dizziness and vertigo demonstrated similar MRI findings characterized by patchy hyperintensity areas in the white matter and external capsule even though she had no risk factors for atherosclerosis. Her third older sister also had dizziness and vertigo and had patchy hyperintensity areas in the white matter in her brain MRI even though she had no risk factors for atherosclerosis. Based on this family history, we suspected that she had cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Mutational analysis of Notch3 gene disclosed a novel missense mutation substituting arginine for cysteine at codon 206 (C206R) in exon 4 of the Notch3 gene, confirming the diagnosis of CADASIL. Interestingly, similar dizziness and vertigo were present not only in the patient, but also in the other two sisters who had the same gene mutation as the patient. This report supports the idea that the external capsule lesion is one of the signs suggestive of CADASIL as a diagnosis.
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PMID:[A case of early stage CADASIL showing only dizziness and vertigo with a novel mutation of Notch 3 gene]. 1571 97

Abundant data now link composition of the vascular wall, rather than the degree of luminal narrowing, with the risk for acute ischemic syndromes in the coronary, central nervous system, and peripheral arterial beds. Over the past few years, magnetic resonance angiography has evolved as a well-established method to determine the location and severity of advanced, lumen-encroaching atherosclerotic lesions. In addition, more recent studies have shown that high spatial resolution, multisequence MRI is also a promising tool for noninvasive, serial imaging of the aortic and carotid vessel wall, which potentially can be applied in the clinical setting. Because of the limited spatial resolution of current MRI techniques, characterization of coronary vessel wall atherosclerosis, however, is not yet possible and remains the holy grail of plaque imaging. Recent technical developments in MRI technology such as dedicated surface coils, the introduction of 3.0-T high-field systems and parallel imaging, as well as developments in the field of molecular imaging such as contrast agents targeted to specific plaque constituents, are likely to lead to the necessary improvements in signal to noise ratio, imaging speed, and specificity. These improvements will ultimately lead to more widespread application of this technology in clinical practice. In the present review, the current status and future role of MRI for plaque detection and characterization are summarized.
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PMID:Magnetic resonance imaging of atherosclerosis. 1572 15

Management of atherosclerotic carotid arteries requires both plaque characterization and determination of the degree of stenosis, especially when carotid stenting (CAS) is being considered for severe carotid stenosis. Recent studies have demonstrated that high-resolution MRI can identify plaque components, such as the lipid-rich necrotic core, intraplaque hemorrhage, fibrous tissue, and the calcification present in human carotid atherosclerosis. The purpose of this study was to assess the feasibility of black blood MRI (BB-MRI) for accurately identifying the plaque components in vivo. Twenty-six consecutive patients scheduled for carotid endarterectomy (CEA) underwent a BB-MRI examination within 2 weeks before the surgical procedure using a 1.5-T Philips scanner with a protocol that generated 2 contrast weightings (T1 and T2). The MR images were acquired using cardiac gating to minimize motion artifact and fat suppression to reduce MR signals from subcutaneous fatty tissue. The plaque evaluations obtained by BB-MRI were compared with the intra-operative video recordings, the excised specimens, and the histological sections. With BB-MRI, the combination of the signal intensities in the T1- and T2-weighted images for each component (lipid deposits, intra-plaque hemorrhage, fibrous plaque, and calcification) showed findings that corresponded with the excised specimens. Complex morphological features could also be assessed by BB-MRI. BB-MRI is a useful method for noninvasively imaging and characterizing atherosclerotic carotid arteries. This MRI technique can provide valuable information that can be used to decide whether to perform a CEA or a CAS in patients with severe carotid stenosis. Furthermore, BB-MRI appears to be a useful tool for the investigation of the pathogenesis and natural history of carotid atherosclerosis.
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PMID:[Noninvasive carotid plaque characterization by black blood MRI]. 1577 12

The currently best available spatial and temporal resolution for retrospectively ECG gated coronary multi-detector-row CT angiography is 0.4 mm and 165 ms, respectively. These acquisition parameters are already rather close to cardiac catheter. Studies so far compared non-invasive coronary CT and convention angiography for the detection of coronary artery stenoses. The most promising result reported by all authors was the high negative predictive value of the CTA. It now needs to be determined if CTA is a reliable tool to rule out coronary artery stenoses in a patient cohort with low likelihood of CAD, such as those with atypical chest pain or ambiguous stress test. CTA may furthermore establish as a rapid and widely available tool to detect vulnerable plaques or intracoronary thrombus in patients with acute coronary syndrome and unstable angina. In patients with chronic stable angina, tools that determine myocardial ischemia under stress such as SPECT and MRI are probably better suited to determine the relevance of coronary artery stenoses. In this particular cohort, by displaying the extent and morphology of coronary atherosclerosis, CTA may help to direct the therapy to either intervention or surgery.
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PMID:Coronary CT angiography in symptomatic patients. 1580 Oct 55

Oxidized low-density lipoprotein (OxLDL) plays a major role in atherosclerosis. We undertook the present study to clarify the relationship between plasma OxLDL and the ischemic volume. We used ELISA to determine plasma OxLDL levels, and performed diffusion- and perfusion-weighted MRI (DWI, PWI) to measure the ischemic volume in 44 ischemic stroke patients. Based on the location of the ischemic lesion, they were divided into three groups: Group I (GI, n = 21) had cortical lesions, Group II (GII, n = 17) had lesions in the basal ganglia or brain stem, and Group III (GIII, n = 6) had massive lesions that involved one entire hemisphere. In GI, but not GII and GIII, plasma OxLDL was significantly higher than in 19 age-matched controls (p < 0.01) and was significantly correlated with the initial ischemic volume visualized on DWI (p = 0.01), PWI (p < 0.01), and the DWI-PWI mismatch (p < 0.05). A persistent increase in plasma OxLDL was associated with enlargement of the ischemic lesion in the early phase after the insult. These findings suggest that elevated plasma OxLDL levels are associated with moderate ischemic damage in patients with cortical lesions (GI), but not those with massive hemispheric lesions (GIII), which may be irreversible. In addition, elevated plasma OxLDL may represent a predictor of enlargement of the ischemic lesion.
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PMID:Elevation of plasma oxidized LDL in acute stroke patients is associated with ischemic lesions depicted by DWI and predictive of infarct enlargement. 1582 67

This chapter reviews current MRI techniques to differentiate stable versus high risk atherosclerosis and discusses the development of non-invasive MR imaging techniques to characterize atherosclerotic plaques. Tissue specific MR signal features will be described according to histo-pathological evaluation standards and comprehensive imaging protocol for the identification of different lesion types will be introduced.
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PMID:MRI plaque tissue characterization and assessment of plaque stability. 1592 37


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