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

The mechanisms of atherogenesis are better understood and the detection of atherosclerosis has improved with the different diagnostic methods currently available. However, it is almost impossible at present to differentiate high risk, unstable or vulnerable plaques from quiescent or stable plaques of atherosclerosis. This is a crucial problem given the banality of atherosclerosis on the one hand, and, on the other hand, the serious consequences (acute coronary syndromes, cerebrovascular accidents) of thrombotic occlusion at the site of an atherosclerotic plaque. It has now been established that the composition of the plaque is more important than the degree of stenosis, a fundamental concept in the risk of plaque rupture, precipitating the cascade of reactions leading to uncontrolled thrombosis. Consequently, new imaging techniques should address the problem of analysing the composition of atheromatous plaques. Endovascular ultrasonography, fast CT, angioscopy, nuclear imaging techniques and MRI are so many promising tools. However, non-invasive techniques should be distinguished from invasive ones. In all probability, it will be the former which will turn out to be the most useful diagnostic aid in pauci or asymptomatic patients. This article reviews the different imaging techniques under evaluation for the identification of risk of plaque rupture.
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PMID:[Identification of unstable coronary atherosclerotic plaques]. 1148 Jan 56

Measuring carotid artery plaque burden from MRI is a reliable method for monitoring regression and progression of atherosclerosis. However, to measure all available images would be very time consuming, and in practice the image quality (IQ) of these images may be inconsistent, which can directly impact the quality of measurement. It is hypothesized that if IQ is comparable among different contrast weighted images, then carotid artery area measurements obtained from different contrast images of the same location will produce identical results. To test this, T1, proton density and T2 weighted images were acquired from ten patients (51 +/- 7 years old). Carotid lumen and vessel wall area was measured using a custom designed software program. The results showed strong agreement evidenced with only small differences on both lumen (mean: 40.5 mm(2)) and wall (mean: 52.6 mm(2)) area measurement among different weighted images. The maximum absolute mean differences are less than 2.7 mm(2) and 4.4 mm(2), and 90(th) percentile of the absolute differences are 5.6 mm(2) and 8.2 mm(2) respectively. In conclusion, different contrast weighted images with high and comparable IQ will yield similar results in lumen and vessel wall area measurement. At each matched location, it is recommended that the image with the highest IQ be used for area measurement.
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PMID:Comparison of carotid vessel wall area measurements using three different contrast-weighted black blood MR imaging techniques. 1155 19

Inflammation contributes to atherosclerosis, but assessment in humans is largely restricted to measurement of markers in blood. We determined whether MRI properties of large arteries were associated with markers of inflammation in serum. Double inversion recovery, fast spin-echo images of the common carotid arteries and infrarenal aorta were obtained at 1.5 T both before and after gadolinium-DTPA (0.1 mmol/kg) in 52 subjects > or =40 years of age, 17 of whom had no risk factors for atherosclerosis and thus served as controls. Twenty-two study participants had increases in wall thickness (14), T2-weighted signal intensity (11), and/or contrast enhancement values (7) that were >2 standard deviations (SDs) from control group mean values. Ten subjects in this group had evidence of focal plaques in the carotids (5) and/or aorta (6). Compared with the remaining 30 subjects, these 22 had significantly higher levels of interleukin-6 (3.53 +/- 2.46 vs. 1.97 +/- 1.37 pg/mL, P = 0.004), C-reactive protein (0.56 +/- 0.98 vs. 0.30 +/- 0.52 mg/dL, P = 0.019), vascular cell adhesion molecule-1 (572 +/- 153 vs. 471 +/- 130 ng/mL, P = 0.012), and intercellular adhesion molecule-1 (244 +/- 80 vs. 202 +/- 45 ng/mL, P = 0.015), and nonsignificant differences in levels of E-selectin (46.1 +/- 18.9 vs. 42.3 +/- 11.3 ng/mL, P = 0.369). Thus, MRI characteristics of the aorta and carotid arteries were associated with elevated serum markers of inflammation, frequently in the absence of definite atheroma. MRI of large arteries may provide a new approach to investigate the contribution of inflammation to atherogenesis.
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PMID:Arterial wall MRI characteristics are associated with elevated serum markers of inflammation in humans. 1174 26

We report a 37-year-old male patient with multiple brain infarcts due to arterial lesions localized in the posterior circulation, who developed a paramedian pontine infarct on the left side. He had been treated as schizophrenia for 20 years. A cranial CT performed one year before showed old small infarcts in the territories of the bilateral thalamo-perforating and left thalamo-geniculate arteries and the right posterior inferior cerebellar artery. The vertebral and basilar arteries were small in diameter on MRI and MR angiography(MRA). Cerebral angiography revealed a narrow smooth basilar artery. In addition, the P2 segments of the bilateral posterior cerebral arteries were markedly narrow with irregular walls. Carotid arteriograms were normal and no atherosclerosis was found. The nature of these arterial lesions remains unknown in this case. Even if MRA shows vertebrobasilar artery hypoplasia, a known congenital risk factor of a posterior circulation infarct, we must rule out a possibility that some arterial pathology is going on.
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PMID:[Juvenile-onset multiple brain infarcts localized in the posterior circulation: a case report]. 1186 48

Cerebrovascular accidents (CVA), or stroke, afflict 731,000 Americans each year, with 165,000 of these individuals dying. Stroke is a major cause of death and disability throughout the world, including southern Africa. Atherosclerosis-related formation of thrombi and emboli at the bifurcation of the common carotid artery and proximal internal carotid artery represents a common cause of stroke. The detection of carotid atherosclerosis by dentists using panoramic radiographs recently has been presented to the public through television news stories and the press, but many dentists still do not know how to interpret panoramic radiographs for detection of this condition. This communication illustrates examples in which carotid atherosclerosis was detected using panoramic radiography. Differential diagnoses are presented. Since not every carotid plaque calcifies, panoramic radiography should never be used alone to exclude the possibility of carotid atherosclerosis. It should also be remembered that the mere presence of calcified carotid plaque is not necessarily a reflection on the degree of carotid stenosis. Definitive diagnosis and treatment requires referral of patients deemed to be at risk to an appropriate physician. A variety of advanced diagnostic methods, including gadolinium-enhanced MRI, Duplex Doppler sonography and angiography are used to confirm carotid stenosis.
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PMID:The role of the dentist in detection of carotid atherosclerosis. 1188 36

Cardiovascular disease is the primary cause of morbidity and mortality in the western world. Complex hemodynamics play a critical role in the development of atherosclerosis and the processes of aging, as well as many other disease processes. Biofluid mechanics play a major role in the cardiovascular system and it is important to understand the forces and movement of blood cells and whole blood as well as the interaction between blood cells and the vessel wall. Fundamental fluid mechanical, which are important for the understanding of the blood flow in the cardiovascular circulatory system of the human body aspects are presented. Measurement techniques for model studies such as LDA, ultrasound, and MRI studies will be discussed. Viscosity and flow behavior changes specifically the creation of vortices and flow disturbances can be used to show how medication can influence flow behavior. Experiments have shown that hemodynamics may have a strong influence on the creation of aneurysms and varicose veins. Other factors such as vessel wall structure are also important. In preliminary studies, it has been demonstrated that geometry and elasticity of vessel walls help determine flow behavior. High velocity fluctuations indicate flow disturbances that should be avoided. Health care practitioners must understand fluid dynamic factors such as flow rate ratio, pressure and velocity gradients, and flow behavior, velocity distribution, shear stress on the wall and on blood cells. These mechanical factors are largely responsible for the deposit of blood cells and lipids, a leading cause of atherosclerosis. The interaction between blood cells and of the cells with the vessel, leads to the formation of plaques and agglomerations. These deposits are found predominantly at arterial bends and bifurcations where blood flow is disturbed, where a secondary flow is created, and where flow separation regions are found. Experiments on hemodynamic effects in elastic silicon rubber models of the cardiovascular system with flow wire, stents, or patches for vessel surgery will be discussed. These studies can be important in improving diagnostics and therapeutic applications.
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PMID:An introduction to biofluid mechanics--basic models and applications. 1193 11

Since the risks for thrombosis are more dependent on plaque composition than on the degree of luminal narrowing, the radiological assessment of atherosclerosis should extend beyond mere depiction of the arterial lumen. High-resolution MRI of the vessel wall can provide important information about the individual makeup of atherosclerotic plaques, potentially enabling early detection and characterization of lesions before narrowing of the vessel lumen occurs. The MR-based assessment of the vessel wall with sufficient spatial resolution and image contrast, however, remains challenging. Requirements include high signal-to-noise ratio, high contrast-to-noise ratio, good signal penetration depth and homogeneous signal throughout the vessel under investigation, as well as imaging protocols encompassing various contrast weightings. Numerous dedicated radiofrequency (RF) coils have been developed to achieve these goals employing either external surface phased-array coils, or alternatively, utilizing intravascular coils to image the vessel wall from inside the vessel and thus being invasive. For the non-invasive approach of imaging with surface coils, the carotid and the right coronary arteries have been favoured since they are of critical importance and since they are relatively superficial structures, accessible from the outside. To detect the early development of plaque and visualize it globally rather than locally, intravascular contrast agents on the basis of ultrasmall particles of iron oxide can be used as a marker of macrophage activity within the plaque. In the long run, it appears likely that the combination of luminal MR angiography with the administration of susceptibility-based contrast agents and subsequent high-resolution MR of detected atherosclerotic lesions with dedicated RF coils could evolve as the diagnostic concept of choice for the assessment of atherosclerotic disease.
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PMID:MR imaging of the vessel wall. 1196 Feb 44

The aim of the study was to evaluate risk factors of atherosclerosis and extra-cerebral target organ damage in patients with hypertension and vascular based mild memory disorders. A group of the study included 20 persons at age of 54-75 (8 males and 12 females) with mild vascular dementia (20-25 pts in MMSE, 22.8 +/- 1.73) with treated mild hypertension. A diagnosis of vascular dementia was confirmed in MRI by two independent experts. All examined patients presented multiinfarction changes in central nervous system as a cause of dementia. The study protocol contained present history, physical examination, 24-hour ambulatory blood pressure monitoring (ABPM), ECG, biochemical tests: total cholesterol, HDL-Ch, LDL-Ch, triglycerides, glucose, urea, creatinine plasma levels and urine test for microalbuminuria. In part of the study group (55%) echocardiography with posterior wall (PW) thickness and ejection fraction (EF) evaluation was performed. In the analysed group mean 24-hour blood pressure values were not elevated (SBP 130.8 +/- 15.8 mm Hg and DBP 77.6 +/- 9.2 mm Hg at day, respectively 121.6 +/- 17.1 mm Hg and 68.2 +/- 11.6 mm Hg at night). No significant (> 10%) nocturnal SBP decrease was observed, however DBP fall was noticed. Either total cholesterol (n < 5.2 mmol/l) or LDL-Ch (n < 3.5 mmol/l) plasma levels were increased in patients with vascular dementia and ranged respectively 5.8 +/- 0.9 and 3.7 +/- 0.9 mmol/l, HDL-Ch and triglycerides levels remained normal (respectively 1.7 +/- 0.5 and 1.5 +/- 1.1 mmol/l). Mean urea and creatinine levels were maintained in normal range (urea 5.8 +/- 1.7 mmol/l, creatinine 75.5 +/- 15.1 mumol/l). In a part of study group (35%) microalbuminuria was presented (urine albumine > 20 mg/l). In majority of patients with hypertension and vascular dementia a few risk factors co-existed. No systolic blood pressure decrease observed at night in 24-hour blood pressure monitoring, though normal mean values, can play an important role in vascular abnormalities progression.
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PMID:[Vascular dementia and systemic changes]. 1218 86

Contrast arteriography is routinely used in the diagnosis and management of coronary atherosclerosis. However, it is recognized that conventional arteriography can not image plaque directly or provide prognostic information based on plaque characterization. Noninvasive, high-resolution magnetic resonance has the potential to image coronary plaque and to determine its composition and microanatomy. This review summarizes the rationale for coronary plaque imaging, and describes the characteristics of plaque using existing MRI techniques. Current and future applications of MRI, including the development of new contrast agents, targeted molecular imaging and the application of MRI to percutaneous coronary intervention are also discussed.
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PMID:Imaging of atherosclerosis. Coronary wall imaging with MRI. 1239 19

Atherogenesis is an inflammatory process that begins in childhood. Early detection of atherosclerosis might allow for selection of subjects at risk for future cerebrovascular events at a time when dietary and lifestyle modification may have its greatest impact, and medical intervention may be useful for those who are refractory to such treatment or who are at greater risk for an event. Early detection relies on a knowledge of the distribution of atheroma formation, which can be predicted by understanding the hemodynamic patterns of blood flow. Early formation is accompanied by a vascular remodeling that normalizes the area of the vessel lumen, making early detection impossible by angiography. Elevated serologic markers of inflammation may be used as evidence of formation of atherosclerosis, but inflammatory markers lack sensitivity and specificity. Preliminary evidence supports the ability of MRI to detect early atheroma formation, possibly even before substantial wall thickening occurs. Once atheroma has formed with measurable stenosis, the goal of imaging studies is to predict stroke risk and determine the need for surgical intervention. Subjects with symptomatic high-grade carotid stenosis have been shown to benefit from surgery with a reduced stroke risk when compared with medical management alone, although controversy exists regarding the management of moderate symptomatic carotid stenosis or asymptomatic carotid disease. In these individuals, understanding atheroma morphology may prove to be of greater utility for assessing stroke risk and determining the appropriate management. Morphologic characterization may also be helpful in monitoring the effect of medical intervention. MRI has proven capable of characterizing the morphologic composition of carotid atheroma, although the clinical implications continue to be investigated.
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PMID:Clinical carotid atherosclerosis. 1248 29


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