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Extent ix, p. Isbn Dimensions unknown Extent ix, p. File format unknown Form of item electronic Isbn Isbn Type electronic bk. Level of compression unknown Other physical details ill. Quality assurance targets not applicable Reformatting quality unknown Reproduction note Electronic reproduction. Sound unknown sound Specific material designation remote. Library Locations Map Details. Allalra Library Borrow it. Reproducibility is best obtained by including the papillary muscles and trabeculae in the LV volume Figure 2.
Allow for LV shortening by careful cross-referencing of planes to delineate the position of the mitral annulus at end-systole and end-diastole. Accurate right ventricular RV assessment demands 3-dimensional techniques because of the non-geometric shape of the ventricle.
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The RV position has also traditionally made reliable echocardiographic measurements difficult. RV dysfunction,as assessed by CMR, predicts a poor prognosis late after myocardial infarction MI , 9 and is of particular importance in pulmonary hypertension and adult congenital heart disease. In many centers, it is customary to use the LV short axis view to assess RV volume.
However, the basal dimension of the RV is considerably larger than the base of the LV, and when errors occur in the base of the RV they may significantly affect accuracy, usually by underestimating RV volumes. When the same series of LV short axis views is used for RV measurements as for LV measurements, the basal end-diastolic and end-systolic slice positions may be difficult to determine. This is compounded because, in most cases, both RV and atrial walls are thin, rendering it difficult to identify the exact plane of the tricuspid valve. RV quantification can be improved by using axial views or, preferably, dedicated RV sequences where the tricuspid valve is imaged in the margin of the slice.
This phenomenon results from inherent relative differences in the volume of distribution of gadolinium Gd between normal and abnormal myocardium. Changes to the interstitium, such as infiltration or fibrosis, increase the volume of distribution, allowing a larger amount of Gd to penetrate into the tissue. Imaging performed late 10 to 20 min after Gd administration allows washout from the myocardial circulation. T2-weighted T2W short-tau inversion recovery STIR imaging is a CMR sequence sensitive to increased myocardial water content, allowing the delineation of high-signal areas of myocardial edema.
Early studies show that increased signal in the myocardium following intravenous Gd accurately depicted irreversible ischemic myocardial injury independent of age. CMR with LGE combined with CT coronary angiography may improve the non-invasive detection of ischemia as a cause for heart failure with high sensitivity and specificity. The presence of mid-wall fibrosis as demonstrated by LGE Figure 5 has also been shown to correlate with a higher rate of all-cause mortality and hospitalization in patients with non-ischemic dilated cardiomyopathy DCM.
Infiltrative cardiomyopathies, which may present either with systolic or diastolic heart failure, arrhythmias or sudden cardiac death, can be difficult to diagnose with traditional imaging techniques. CMR provides accurate assessment of ventricular morphology and LGE, allowing imaging of abnormal areas of myocardium, with particular patterns of LGE correlating with the underlying infiltrative diagnosis.
Knowledge of such etiologies in patients presenting with HF may influence treatment decisions, such as a need for implantable defibrillator insertion, and provide an opportunity for disease-specific therapy. CMR has advantages over echocardiography in the detection of intraventricular thrombi. T1W images acquired immediately after administration of Gd can distinguish thrombus from surrounding myocardium or tumor. When imaging immediately after Gd contrast administration, myocardium or tumor demonstrate increased signal due to vascularity and perfusion, whereas thrombus, being avascular, remains dark.
Left atrial appendage thrombus can also be seen on CMR, but the diagnostic accuracy of CMR in this area is yet to be determined. The anatomic mechanisms and quantification severity can be assessed by CMR. Echocardiographic measurements of regurgitation may be inaccurate, particularly in dilated ventricles. The regurgitant volume can readily be calculated.
Similar CMR techniques can be used for quantification of tricuspid, aortic and pulmonary regurgitation. In particular, phase-contrast flow quantification across the semilunar valves offer an accurate measurement of forward and backward flow, 57 and may offer superior reproducibility to echocardiography. Echocardiography is the best-established non-invasive technique for the evaluation of diastolic dysfunction.
Measurements of mitral A-wave and E-wave velocity and deceleration times, and systolic and diastolic wave velocities in the pulmonary flow traces,have been shown to be reliable and easy to obtain. CMR provides the best imaging technique available for assessment of RV free wall contraction abnormalities and is particularly valuable in assessing patients with suspected arrhythmogenic RV dysplasia ARVD.
It should be noted that fatty infiltration, as defined in the current diagnostic criteria, is a histological diagnosis not an imaging diagnosis, and the prevalence of RV fat by CMR in the normal population has not been fully elucidated. In the 4-chamber view, the LV lateral wall and septal contractility can be carefully evaluated frame-by-frame in relation to tricuspid and mitral valve opening as well as atrial contraction. It has been well demonstrated, however, that patients with a large volume of myocardial scar, as determined by CMR, respond poorly to biventricular pacing.
Contstrictive pericarditis is notoriously difficult to diagnose, often with subtle echocardiographic and invasive hemodynamic findings. CMR provides an accurate assessment of pericardial thickness, using double and triple inversion recovery sequences, as well as being able to non-invasively demonstrate ventricular interdependence.
Real-time imaging allows assessment of the ventricular interdependence and abnormal septal motion seen in constrictive physiology. This is done in the LV short axis view with images, including the domes of the diaphragm,in order to observe respiratory motion. The anatomy of the great vessels and branches are exquisitely shown on CMR, particularly with contrast-enhanced 3-dimensional magnetic resonance angiography 3D-MRA.
Lack of ionizing radiation and high reproducibility make 3D-MRA useful for longitudinal follow-up of patients with vascular abnormalities, particularly surgical shunts or dissection. MR pulmonary angiography is also useful in evaluation and surgical planning for chronic thromboembolic disease Figure 8. In spite of its advantages, CMR does have some limitations in patients with dysrythmias that affect ECG-gating, claustrophobia, implantable devices, and severe renal impairment. Parallel imaging has improved acquisition time, and automated software has reduced analysis time, however CMR remains a specialized technique requiring considerable expertise for both acquisition and interpretation.
CMR uniquely provides accurate and reproducible measures of volumes and function of all 4 cardiac chambers and surrounding vasculature. It provides excellent morphological information with unparalleled definition between blood pool and myocardium. Combined with the known patterns of LGE, CMR provides a powerful tool for the diagnosis and quantification of myocardial infarction. It provides prognostic information prior to either revascularization or ventriculoplasty.senkeysandcuc.tk
Atlas of practical applications of cardiovascular magnetic resonance - University Of Pikeville
Non-ischemic patterns of LGE may reveal infiltrative conditions that are often difficult to diagnose with other techniques, and which may significantly alter clinical management. CMR is an ideal technique to evaluate complications such as intracardiac thrombus or valve dysfunction.
It has significant advantages in evaluation of the RV, which is increasingly recognized as an important and prognostic factor in HF and congenital heart disease. Cardiovascular magnetic resonance from basics to clinical applications. Appl Radiol. Clinical Departments Cardiovascular magnetic resonance from basics to clinical applications. The performance of RV wall stress as a predictor of survival was tested using a Cox proportional hazards multiple regression analysis using the first principal component of the 3D wall stress data with all-cause mortality as the outcome variable.
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Survival was defined as the time between date of the CMR imaging and death from any cause. We report data from PH subjects Imaging in healthy volunteers In all subject groups, segmentation was successful and no data were excluded from analysis.
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Variables are shown for the entire UK group and those with metabolomics as well as the healthy controls. Median RV WT was 3. The RV free wall in the inlet region had the greatest absolute 3. Compared with healthy adults the RV outflow showed the greatest regional expansion in shape 1. Overall, median RV wall stress was Three-dimensional models of the right ventricle in PH patients.
Co-registered phenotypic data were used to create a map of RV features across the population. The RV is shown from two viewpoints with the left ventricle represented in grey. These phenotypic data were then used in 3D regression models with haemodynamic variables or metabolomics levels as explanatory variables. Statistical models of the right ventricle in PH patients. The RV is shown from three viewpoints with the left ventricle represented in grey.
A positive regional relationship with mPAP is indicated in red and a negative relationship in blue. Statistical models of the relationship between right ventricular wall stress and two metabolites in PH patients. A positive relationship between metabolite level and regional wall stress and is indicated in red and a negative relationship in blue. We developed a fully automated approach for 3D modelling of the right ventricle in patients with PH enabling a comprehensive quantitative analysis of the complex relationship between elevated afterload, serum biomarkers and structural adaptation.