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

Thoracic aortic atherosclerosis has been shown to be an important cause of severe morbidity and mortality. At the present time, the case of performance, detailed information obtainable, and availability make TEE the procedure of choice for the imaging of thoracic aortic atherosclerosis; however, further technical advances in MR and CT, particularly in MR plaque characterization and the use of plaque specific contrast agents, may allow for a less invasive and more complete evaluation of thoracic aortic atherosclerosis in the near future. Gadolinium-enhanced 3DMRA is the procedure of choice for the noninvasive detection of plaque in the proximal aortic arch vessels. Furthermore, both CT and MRI are better suited to evaluate penetrating atherosclerotic ulcers and their complications such as intramural hematoma, pseudoaneurysm formation, and aortic rupture.
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PMID:Diagnostic imaging of aortic atherosclerosis and its complications. 1248 31

In the future, the use of imaging methods to quantify the progression and regression of atherosclerosis could play a strong role in the management of patients. High-resolution, noninvasive MRI may provide exhaustive 3-D anatomic information about the lumen and the vessel wall. Furthermore, MRI has the ability to characterize plaque composition and microanatomy and therefore to identify lesions vulnerable to rupture or erosion. The high resolution of MRI and the development of sophisticated contrast agents offer the promise of molecular in vivo molecular imaging of the plaque. This may aid early intervention (e.g., lipid lowering drug regiments) in both primary and secondary treatment of vascular disease in all arterial beds.
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PMID:Noncoronary and coronary atherothrombotic plaque imaging and monitoring of therapy by MRI. 1248 33

The biophysical properties of the aortic wall seems to play a significant role in the pathogenesis of cardiovascular disease such as atherosclerosis, hypertension, aneurysm formation, Marfan's syndrome, and in normal aging. The presence and the proportion of smooth muscle, collagen, and elastin proteins contribute to the compliance of the vessel wall with the latter being the most extensible component. However, elastin fibers fracture at low stresses contributing to a decrease of the aortic compliance and consequently to an elevation of the pulse pressure, which is a risk factor of cardiovascular disease. Early detection of a decrease in the aortic compliance could help to identify early cardiovascular disease in asymptomatic patients and monitor the results of the therapeutic interventions. Therefore, estimation of the aortic compliance can be used for both screening as well as long-term follow-up. Magnetic resonance imaging which is a noninvasive, accurate, and reproducible method can estimate the compliance of the aortic wall either by measuring the relative change in cross sectional area of a chosen segment using ECG-triggered spin echo or gradient echo sequences or by measuring the pulse wave velocity through the aorta using the phase contrast-magnetic resonance imaging (PC-MRI) technique. Both techniques have been validated and many sudies suggest MRI as a valuable tool for evaluating aortic wall function. However, large prospective studies are mandatory for the method to be established as a screening tool.
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PMID:The clinical significance of aortic compliance and its assessment with magnetic resonance imaging. 1254 35

Coagulation disorders are common in cancer patients. In patients with solid tumors, a low-grade activated coagulation can result in systemic and cerebral arterial or venous thrombosis. Cancer treatments may also contribute to this coagulopathy, which usually, but not exclusively, occurs in the setting of advanced malignant disease. There may be TIAs or cerebral infarctions. Because of the widespread distribution of cerebral thromboses, there may be a superimposed encephalopathy; sometimes this is the only sign. Concurrent systemic thrombosis is present in many patients and is a useful clue to the diagnosis. In cerebral venous occlusion, the initial symptom is usually a headache. Except for cerebral intravascular coagulation that is unassociated with NBTE, neuriomaging studies usually demonstrate one or more parenchymal infarctions. MRI or MRV may demonstrate venous thrombosis. The laboratory evidence of coagulopathy is difficult to distinguish from the asymptomatic coagulopathy that often accompanies advanced cancer, and the test results must be interpreted cautiously. NBTE can be diagnosed by transesophageal echocardiography. There is no established treatment for the thrombotic coagulopathy associated with cancer, but anticoagulation should be considered. In leukemia and lymphoma, the coagulopathy is typically acute DIC that can lead to systemic and brain hemorrhages. It is especially common in acute myelogenous leukemias. The clinical signs of cerebral hemorrhage are fulminant and may be fatal. The bleeding usually occurs in the brain or subdural compartment, and rarely in the subarachnoid space. The diagnosis can be suspected by the clinical setting and by systemic thrombosis or hemorrhage. It can be established by examination of the peripheral smear, the platelet count, and tests of coagulation function. Therapy of acute DIC is controversial and should be individualized for the clinical setting. Cerebrovascular disorders can complicate metastatic or primary tumor in the brain, skull, dura, or leptomeninges. The clinical signs of infarction are indistinguishable from other causes of stroke, except that tumor-related venous occlusion will usually first produce signs of increased intracranial pressure. The diagnosis of tumor-related infarction can usually be established by neuroimaging studies that show infarction and may show extracerebral sites of tumor. CSF examination is useful in diagnosing leptomeningeal metastasis. A search for lung or cardiac tumor should be performed when embolic tumor infarction is suspected. Primary or metastatic tumors in the brain or dura may hemorrhage, producing the initial clinical signs of the brain tumor or a change in chronic signs induced by the tumor. There are helpful clues to a neoplastic hemorrhage on brain CT or MRI scans. The brain hemorrhage may require evacuation and the underlying tumor will usually require additional antineoplastic treatment. Hyperleukocytosis (extreme elevation of the cell count) in acute myelogenous leukemia is a less common cause of brain hemorrhage in recent years because of improved methods to lower the cell count. Cerebral arterial or venous thrombosis is sometimes the result of cancer therapy. The attribution of thrombosis to chemotherapy in many published cases is only speculative, because carefully conducted prospective studies that include investigation for other thrombotic causes are not available. The best-known associations with thrombosis are L-asparaginase, which is typically used in the induction therapy of acute lymphocytic leukemia, and combination hormonal therapy and chemotherapy for breast cancer. Radiation to the head and neck, typically administered for head and neck epithelial cancers or lymphoma, may result in delayed carotid atherosclerosis. The distribution of stenosis or occlusion is within the radiation portal and is typically more extensive than is atherosclerosis that develops in the absence of radiation. Small clinical series suggest that surgical treatment is equally effective as in nonirradiated carotid atherosclerosis. In children, the cerebral vessels can be affected by brain radiation resulting in stenosis or occlusion. Brain hemorrhages can result from chemotherapy effects on the hemostatic system or a microangiopathic anemia. Hemorrhages from radiation-induced vascular abnormalities are rare. Opportunistic infections, especially fungal infections, can complicate cancer or its treatment. Septic cerebral emboli may result in focal cerebral signs, seizures, or encephalopathy. Sometimes there is an associated hemorrhagic vasculitis or cerebritis. Rarely, mycotic aneurysms may bleed. A high index of suspicion is needed to diagnose fungal infection because of the difficulty in culturing the organism from the blood or CSF. A clinician can usually establish the cause of stroke in the cancer patient by performing a careful review of the clinical setting--including the type and extent of cancer and the type of antineoplastic therapy--in which the stroke occurred. Systemic thrombosis, embolism, or hemorrhage can be a clue to the cause, and appropriate neuroimaging and coagulation studies to aid in the diagnosis are available. Therapy may ameliorate symptoms or prevent further episodes. The identification of one of these unusual stroke syndromes that leads to the diagnosis of an occult and treatable cancer can be particularly rewarding.
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PMID:Cerebrovascular complications in cancer patients. 1269 Jun 49

The role of diagnostic imaging in the study of atherosclerosis of carotid and intracranial vessels is analyzed, after the illustration of the main characteristics of the disease. Atherosclerosis should be considered a systemic disease, however it tends to be segmental. The commonest sites are the coronary artery, the superficial femoral artery, the subrenal aorta and the carotid arteries at the level of the bifurcation. Traditionally, the percentage of intraluminal stenosis has represented the standard measurement of the severity of atheromatosis. However, the grade of stenosis is not the only sign predictive of clinical complications. The most vulnerable plaques show predominant core necrosis or hemorrhage, separated from the vascular lumen by a thin unstable fibrous cap. The two major aspects of lesions at high risk of rupture are the presence of a large soft core and the status of the fibrous cap that can be intact, ruptured or infiltrated by inflammatory cells. Imaging procedures should be addressed to the identification of these pathologic conditions predisposing to the embolic-thrombotic complication. However, additional information on blood flow dynamics, vascular collateral compensation and brain perfusion is useful for decision-making about the therapeutic approach. This is the reason why in diagnostic imaging of atheromatosis, digital angiography should be combined with color Doppler-US, CT and MRI.
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PMID:Atherosclerosis of carotid and intracranial arteries. 1269 80

We have evaluated the relationship between carotid atherosclerotic change and periventricular hyper intensity (PVH). PVH was studied in 66 cases with cerebral thrombosis, comparing them with another group of age-matched controls, which consisted of 29 cases with hypertension, diabetes, and hypercholesteremia. MRI (fluid attenuated inversion recovery) and B-mode carotid ultrasonography of each lesion were analyzed. Thrombosis lesions, compatible with neurological manifestation were divided into two types, cerebral cortical type (including centrum semiovale type) and small infarction in the deep subcortical type. PVH was classified into 4 grades, none, rims/caps, patchy and diffuse. Smooth PVH was, adjoining the anterior/posterior angles and the margins of the lateral ventricles, were defined as caps and rims. Irregular PVH areas, confluent with each other, were defined as patchy, while diffuse PVH areas extending below the cortex beyond the level of the corpus callosum were defined as diffuse. Carotid atherosclerosis was evaluated using B-mode carotid ultrasonography. The severity of carotid atherosclerosis was assessed by using two indicators; incidence of carotid atherosclerosis and maximum percentage diameter of the stenosis areas. Patchy and diffuse type PVH was frequent in the thrombosis group. On B-mode carotid ultrasonography, diffuse PVH was prominent in patients with stenotic change and high maximum percentage of stenosis, but none/rims/caps PVH was accompanied by variable B-mode carotid ultrasonographical findings. Six patients had ulcerated plaques and they suffered more frequently with diffuse PVH. Diffuse PVH was more frequent in cases with severe carotid stenosis than in other PVH types. These findings suggested that large vessel atherosclerosis could result in diffuse PVH.
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PMID:[The relationship between extracranial carotid atherosclerosis in an ultrasound study and periventricular hyperintensity in MR images]. 1270 20

Diagnosis depends on the clinical manifestations, blood or cerebrospinal fluid study and MRI findings. Acute and subacute intraparenchymal spinal cord disorders are due to vascular disorders or myelitis. Spinal cord infarction is associated with dissecting aortic aneurysm, surgical clipping of aortic aneurysms, aortic atherosclerosis or hypotension from any cause. Hematomyelia results from trauma, vascular malformations, vasculitis, or a coagulation disorder. Acute infectious myelopathies result from direct invasion of the spinal cord by bacteria, parasite, or virus. The cause of acute or subacute inflammatory disease include multiple sclerosis, Devic disease, acute disseminated encephalomyelitis, SLE, or sarciodosis. Sarcoidosis sometimes requires differential diagnosis with cord tumor. Chronic intraparenchymal spinal cord disorders are due to syringomyelia, familial spastic paraplegia, HTLV-1 associated myelopathy, adrenomyeloneuropathy, and vascular malformations. HTLV-1 associated myelopathy present with progressive spastic paraplegia with bladder disturbance and has antibodies to HTLV-1 in the cerebrospinal fluid and serum. Diagnosis of adrenomyeloneuropathy is made by demonstration of elevated levels of very long chain fatty acids in plasma. Vascular malformations are important lesions because they present a treatable cause of progressive myelopathy.
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PMID:[Medical approach to intraparenchymal spinal cord disorders]. 1278 77

The prevalence of atherosclerosis in the abdominal aorta increases with age and is hypothesized to be related to adverse hemodynamic conditions including flow recirculation and low wall shear stress. Exercise has been shown to modulate these adverse conditions observed in the infrarenal aorta of healthy young subjects at rest. A custom magnetic resonance (MR)-compatible stationary cycle, an open MRI, and custom image processing software were used to quantify hemodynamic conditions in the abdominal aorta at rest and during cycling exercise in healthy subjects aged 50-70 years. The subjects increased their heart rate from 63+/-8 bpm at rest to 95+/-12 bpm during cycling exercise. Supraceliac blood flow increased from 2.3+/-0.4 to 6.0+/-1.4 l/min (P<0.001) and infrarenal flow increased from 0.9+/-0.3 to 4.9+/-1.7 l/min (P<0.001) from rest to exercise. Wall shear stress increased from 2.0+/-0.7 to 7.3+/-2.4 dynes/cm(2) at the supraceliac level (P<0.001) and 1.4+/-0.8 to 16.5+/-5.1 dynes/cm(2) at the infrarenal level (P<0.001) from rest to exercise. Flow and shear oscillations present at rest were eliminated during exercise. At rest, these older subjects experienced lower mean wall shear stress at the supraceliac level of the aorta and greater oscillations in wall shear stress as compared to a group of younger subjects (23.6+/-2.2 years). Compared to the younger subjects, the older subjects also experienced greater increases in mean wall shear stress and greater decreases in wall shear stress oscillations from rest to exercise.
Atherosclerosis 2003 Jun
PMID:Abdominal aortic hemodynamic conditions in healthy subjects aged 50-70 at rest and during lower limb exercise: in vivo quantification using MRI. 1280 16

Genetically engineered mouse models provide enormous potential for investigation of the underlying mechanisms of atherosclerotic disease, but noninvasive imaging methods for analysis of atherosclerosis in mice are currently limited. This study aimed to demonstrate the feasibility of MRI to noninvasively visualize atherosclerotic plaques in the thoracic aorta in mice deficient in apolipoprotein-E, who develop atherosclerotic lesions similar to those observed in humans. To freeze motion, MR data acquisition was both ECG- and respiratory-gated. T(1)-weighted MR images were acquired with TR/TE approximately 1000/10 ms. Spatial image resolution was 49 x 98 x 300 micro m(3). MRI revealed a detailed view of the lumen and the vessel wall of the entire thoracic aorta. Comparison of MRI with corresponding cross-sectional histopathology showed excellent agreement of aortic vessel wall area (r = 0.97). Hence, noninvasive MRI should allow new insights into the mechanisms involved in progression and regression of atherosclerotic disease.
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PMID:High-resolution MRI with cardiac and respiratory gating allows for accurate in vivo atherosclerotic plaque visualization in the murine aortic arch. 1281 80

High-resolution MRI provides unique information about morphology of atherosclerotic carotid plaque. In this study, the accuracy and precision of measurements of carotid plaque burden and lumen narrowing were determined for in vivo black blood MRI assessment with respect to ex vivo MRI in a group of 37 atherosclerosis patients who underwent carotid endarterectomy (CEA). Three different plaque measures were compared between paired in vivo and ex vivo MR images: maximum wall area (MWA), minimum lumen area (mLA), and wall volume (WV). MWA and WV are measures of plaque burden, while mLA is a measure of lumen narrowing. The matched in vivo and ex vivo measurements showed good agreement (the correlation coefficients for in/ex vivo WV, MWA, and mLA were 0.92, 0.91, 0.90, respectively) with predictable bias. This study indicates that in vivo black blood MRI can be used to directly estimate the morphology of the plaque. Comparison of the three plaque measures showed that mLA and MWA or WV provide different information regarding the atherosclerotic lesions (the correlation coefficients between mLA and MWA or WV were less than 0.3). Black blood MRI technique is a potentially powerful clinical tool to characterize the severity of atherosclerotic plaque. It can provide accurate measurements on different aspects of the plaque, from plaque burden to lumen narrowing.
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PMID:Accuracy and uniqueness of three in vivo measurements of atherosclerotic carotid plaque morphology with black blood MRI. 1281 81


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