Targeted Knockdown of Hepatic SOAT2 With Antisense Oligonucleotides Stabilizes Atherosclerotic Plaque in ApoB100-only LDLr-/- Mice.

Objective: To test the hypothesis that the attenuation of cholesterol oleate packaging into apoB-containing lipoproteins will arrest progression of pre-existing atherosclerotic lesions.

Approach And Results: Atherosclerosis was induced in apoB-100 only, LDLr(-/-) mice by feeding a diet enriched in cis-monounsaturated fatty acids for 24 weeks. A subset of mice was then euthanized to quantify the extent of atherosclerosis.

Functionalization of gadolinium metallofullerenes for detecting atherosclerotic plaque lesions by cardiovascular magnetic resonance.

Background: The hallmark of atherosclerosis is the accumulation of plaque in vessel walls. This process is initiated when monocytic cells differentiate into macrophage foam cells under conditions with high levels of atherogenic lipoproteins. Vulnerable plaque can dislodge, enter the blood stream, and result in acute myocardial infarction and stroke.

Non-contrasted computed tomography for the accurate measurement of liver steatosis in obese patients.

Background: Hepatic macrosteatosis (HMS) is prevalent among high BMI patients, but a lack of validation of non-invasive measures of liver fat hampers non-alcoholic liver disease (NAFLD) investigation in general. Recent work suggests BMI adjusted, non-contrasted computed tomography (nc-CT) attenuation data (Hounsfield units) reflects liver fat accumulation in a normal weight population. However, this and other CT-based HMS studies have only approximated macrosteatosis (%) histologically, but have not validated findings with chemical liver triglyceride (TG) concentrations (mg/gram protein).

Early stages of in situ bladder regeneration in a rodent model.

Surgical removal of approximately 70% of the bladder (subtotal cystectomy [STC]) was used as a model system to gain insight into the normal regenerative process in adult mammals in vivo. Female F344 rats underwent STC, and at 2, 4, and 8 weeks post-STC, bladder regeneration was monitored via microcomputed tomography scans, urodynamic (bladder function studies) pharmacologic studies, and immunohistochemistry. Computed tomography imaging revealed a time-dependent increase in bladder size at 2, 4, and 8 weeks post-STC, which positively correlated with restoration of bladder function.

Proton magnetic resonance spectroscopy detection of neurotransmitters in dorsomedial medulla correlate with spontaneous baroreceptor reflex function.

Control of heart rate variability via modulation of sympathovagal balance is a key function of nucleus tractus solitarii and the dorsal motor nucleus of the vagus localized in the dorsomedial medulla oblongata. Normal blood pressure regulation involves precise balance of glutamate (Glu)-glutamine-gamma-aminobutyric acid transmitter systems, and angiotensin II modulates these transmitters to produce tonic suppression of reflex function. It is not known, however, whether other brain transmitters/metabolites are indicators of baroreflex function.

Adverse effect of increased left ventricular wall thickness on five year outcomes of patients with negative dobutamine stress.

Background: To determine if patients without dobutamine induced left ventricular wall motion abnormalities (WMA) but an increased LV end-diastolic wall thickness (EDWT) exhibit a favorable cardiac prognosis.

Results: Between 1999 and 2001, 175 patients underwent a dobutamine stress cardiovascular magnetic resonance (DCMR) procedure utilizing gradient-echo cines. Participants had a LV ejection fraction >55% without evidence of an inducible WMA during peak dobutamine/atropine stress.

Location of arterial stiffening differs in those with impaired fasting glucose versus diabetes: implications for left ventricular hypertrophy from the Multi-Ethnic Study of Atherosclerosis.

Objective: To determine whether middle-aged and older individuals with impaired fasting glucose (IFG), but no clinical evidence of cardiovascular disease, exhibit abnormal changes in proximal thoracic aortic stiffness or left ventricular (LV) mass when compared with healthy counterparts.

Research Design And Methods: From the Multi-Ethnic Study of Atherosclerosis, 2,240 subjects with normal fasting glucose (NFG), 845 with IFG, and 414 with diabetes, all aged 45 to 85 years and without preexisting coronary artery disease, underwent MRI determinations of total arterial and proximal thoracic aortic stiffness and LV mass. The presence or absence of other factors known to influence arterial stiffness was assessed.

Prediction of cardiac events in patients with reduced left ventricular ejection fraction with dobutamine cardiovascular magnetic resonance assessment of wall motion score index.

Objectives: The purpose of this study was to assess the utility of dobutamine cardiovascular magnetic resonance (DCMR) results for predicting cardiac events in individuals with reduced left ventricular ejection fraction (LVEF).

Background: It is unknown whether DCMR results identify a poor cardiac prognosis when the resting LVEF is moderately to severely reduced.

Methods: Two hundred consecutive patients ages 30 to 88 (average 64) years with an LVEF View Article and Find Full Text PDF

Pulmonary extramedullary hematopoiesis.

Extramedullary hematopoiesis (EMH) is the formation and development of blood cells outside of the bone marrow. Of particular interest to chest physicians and radiologists is the occurrence of EMH in the lungs and pleura. There have been several reports of patients presenting with pulmonary EMH published in the literature and the majority are due to a secondary process, such as myeloproliferative disorders, hemolytic anemias, hereditary spherocytosis, and Gaucher disease.

Left ventricular spherical remodeling and apical myocardial relaxation: cardiovascular MR imaging measurement of myocardial segments.

Purpose: To prospectively evaluate left ventricular (LV) shape and regional relaxation to determine if rapid, early relaxation of the LV is lost with spherical remodeling of the LV.

Materials And Methods: This HIPAA-compliant study was approved by the institutional review board. All participants gave written informed consent.

Leg flow-mediated arterial dilation in elderly patients with heart failure and normal left ventricular ejection fraction.

Background: flow-mediated arterial dilation (FMAD), an indicator of endothelial function, is reduced in patients with heart failure and reduced left ventricular ejection fraction (HFREF). Many elderly patients with heart failure exhibit a normal left ventricular ejection fraction (HFNEF). It is unknown whether FMAD is severely reduced in the elderly with HFNEF.

Cardiovascular magnetic resonance measurement of coronary arterial blood flow at rest and after submaximal exercise.

Objective: Because most daily activities are conducted at submaximal exercise level, treatments are implemented to improve submaximal coronary artery blood flow (CABF). We sought to validate the reproducibility of cardiovascular magnetic resonance imaging measurements of submaximal CABF.

Methods: We measured CABF in the left anterior descending artery in 11 healthy postmenopausal women at rest and after submaximal bike exercise on 2 occasions 8 to 16 weeks apart.

Effect of the transmural extent of myocardial scar on left ventricular systolic wall thickening during intravenous dobutamine administration.

Using magnetic resonance imaging, the extent of scar tissue due to chronic infarction and quantification of dobutamine systolic wall thickening (SWT) can be measured simultaneously in human subjects. To determine whether the transmural extent of scar tissue determines dobutamine SWT in chronic ischemic heart disease, we assessed the transmural extent of hyperenhancement and dobutamine SWT with magnetic resonance imaging in 16 patients. The transmural extent of hyperenhancement correlated inversely with dobutamine SWT (r = -0.

Cardiovascular magnetic resonance imaging.

Recent advancements in magnetic resonance imaging hardware and software permit the assessment of cardiovascular structure and function at rest and during exercise or pharmacology-induced cardiac stress. With these developments, knowledge of cardiovascular imaging protocols in the magnetic resonance imaging environment is critical for nursing personnel. The purpose of this article is to review information pertinent to working in a magnetic resonance imaging environment and to describe the requirements of nursing personnel performing cardiovascular magnetic resonance imaging examinations.

Relation of cardiac prognosis to segment location with apical left ventricular ischemia.

Previously, we have shown that myocardial ischemia induced during intravenous dobutamine in the distal segments composing the left ventricular apex is associated with a heightened risk of future myocardial infarction or cardiac death. In this study, we find this heightened risk is present independent of the location of the distal segment within the left ventricular apex.

Feasibility to detect severe coronary artery stenoses with upright treadmill exercise magnetic resonance imaging.

We performed treadmill exercise magnetic resonance imaging in 27 patients with exertional chest pain who were referred for contrast coronary angiography to determine the feasibility of this method to identify severe coronary artery stenoses. The sensitivity and specificity for detecting >70% coronary artery luminal diameter narrowings on contrast coronary angiography were 79% and 85%, respectively.

Assessment of cardiac function with MR imaging.

A variety of black or white blood imaging techniques are available for assessing global and regional LV and RV function during cardiovascular MR imaging examinations. In addition to providing information about LV function at rest, these techniques provide diagnostic and prognostic information regarding myocardial ischemia and viability during MR imaging stress tests.

Automated analysis of phase-contrast magnetic resonance images in the assessment of endothelium-dependent flow-mediated dilation.

Measurement of flow-mediated arterial dilation (FMAD) provides information regarding the status of peripheral arterial endothelial function. Although phase-contrast magnetic resonance imaging (PC-MRI) can be used to measure FMAD, the manual analysis of one study (tracing regions of interest and processing data on 100 images) can require six or more hours. To enhance the clinical utility of the PC-MRI assessment of FMAD, we hypothesized that an automated technique (Multi-Stage Intensity Thresholding or MSIT) for determining femoral arterial area and flow before and after cuff inflation over the thigh could be used to evaluate FMAD in a rapid, accurate, and reproducible manner.

Relation of aortic distensibility determined by magnetic resonance imaging in patients > or =60 years of age to systolic heart failure and exercise capacity.

Aortic stiffness increases with advancing age and is associated with the age-related decline in exercise capacity in healthy persons. Previous studies have suggested that aortic compliance is reduced in heart failure (HF). Older persons with systolic HF can have particularly severe exercise intolerance.

Magnetic resonance imaging determination of cardiac prognosis.

Background: Regional assessments of left ventricular (LV) wall motion obtained during MRI cardiac stress tests can be used to identify myocardial injury and ischemia, but the utility of MRI stress test results for the assessment of cardiac prognosis is not known.

Methods And Results: Two hundred seventy-nine patients referred (because of poor LV endocardial visualization with echocardiography) for dobutamine/atropine MRI for the detection of inducible ischemia were followed for an average of 20 months. After MRI stress testing, the occurrence of myocardial infarction, cardiac death, death attributable to any cause, coronary arterial revascularization, and unstable angina or congestive heart failure requiring hospitalization was determined.

Effects of phase encode order and segment interpolation methods on the quality and accuracy of myocardial tags during assessment of left ventricular contraction.

Tissue tagging can be implemented during cardiovascular magnetic resonance imaging exams to assist with the quantification of left ventriculargeometry, volume and ejection fraction, endocardial thickening and relaxation, and myocardial stress-strain relationships. During tagged cine gradient echo image acquisitions of left ventricular wall motion, rows of k-space data can be acquired with various phase-encoding orders, and the reconstruction of supplemental images can be accomplished using a variety of interpolation techniques. In this study, we investigated the utility of various phase order and segment interpolation methods for determining accurate tag displacement trajectories.

Noninvasive Imaging of the Thoracic Aorta.

Thoracic aortic disease is a common problem affecting the geriatric population of the U.S. Thoracic aortic aneurysms and aortic dissection and its variants are the most common diseases of the thoracic aorta, often leading to death if not treated immediately.