Mouse models are expected to play an important role in future investigations of human cardiac diseases. In the present report, MRI methods for determining global and regional cardiac function in the mouse are demonstrated. ECG-gated cine images were acquired in five C57BL/6 mice at physiological temperatures (37°C) and heart rates of 500 ؎ 50 beats per minute. Left ventricular mass, ejection fraction, and cardiac output were estimated from the resulting images. Regional myocardial function was also determined in three animals by application of 2D SPAtial Modulation of Magnetization (SPAMM) in combination with the cine protocol. The quality of the tagged images was sufficient to allow mapping of myocardial strains and displacements. The results of the regional strain analysis were consistent with similar studies in larger animals. Recent advances in molecular genetics and the description of the mouse genome have made the mouse a key model for understanding and characterizing human diseases. Of the many disorders for which murine models are suitable, heart failure is known to contribute to more fatalities in developed countries than any other disease (1). These facts have been the driving force in the development of numerous genetically engineered murine models for studying a broad spectrum of heart disease. Targeted ablation (knockout) or overexpression (knockin) of genes responsible for various aspects of cardiac development, differentiation, and function have yielded mouse models of cardiac hypertrophy (2), dilated cardiomyopathy (3), and hypertrophic cardiomyopathy (4). More sophisticated models that allow controlled activation of a specific gene have been demonstrated and continue to be developed (5). The study of these models would benefit significantly from a nondestructive and noninvasive method for the detailed assessment of heart function.Two-dimensional and M-mode echocardiography are frequently used tools for evaluating global and regional cardiac function in mouse models (6). The method is inexpensive, portable, and well-suited for repeated studies. However, quantitative echocardiography makes use of geometric assumptions and is subject to variability, especially for deformed ventricles.MRI methods for determining cardiac function utilize tomographic acquisition techniques and as such are free from these complications. MRI has been shown to yield accurate and reliable quantification of murine global myocardium function, left ventricular (LV) mass, and right ventricular size (7-9). A particularly useful and unique capability of MR is the ability to noninvasively generate fiducial markers. Spatial modulation of magnetization (SPAMM) uses gradient and RF pulses to generate a grid of dark bands within an image (10,11). These bands track the deformation of the myocardium during the heart cycle and can be used to extract regional measures of the strain within the tissues. Myocardial strain parameters measured by this method have been validated by comparison to sonomicrometry (12) and databases of normal val...

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Sialoadenitis of HCV-related liver disease is common but differs from SS with regard to predisposing genetic factors, expression of autoimmune markers, and histopathologic severity.

Background Pulmonary artery acceleration time measured by echocardiography inversely correlates with pulmonary artery pressures in adults and children older than 1 year of age. There is a paucity of data investigating this relationship in young children, particularly among preterm infants. Objective To characterize the relationship between pulmonary artery acceleration time (PAAT) and pulmonary artery pressures in infants. Design/Methods Patients ≤ 1 year of age at Children's Hospital of Philadelphia between 2011 and 2017 were reviewed. Infants with congenital heart disease were excluded, except those with a patent ductus arteriosus (PDA), atrial septal defect (ASD), or ventricular septal defect (VSD). Linear regression analysis was used to assess the correlation between PAAT measured by echocardiography and systolic pulmonary artery pressure, mean pulmonary artery pressure, and indexed pulmonary vascular resistance from cardiac catheterization. Results Fifty‐seven infants were included, of which 61% were preterm and 49% had a diagnosis of bronchopulmonary dysplasia. The median postmenstrual age and weight at catheterization were 51.1 weeks (IQR 35.8–67.9 weeks) and 4400 g (IQR 3100–6500 g), respectively. Forty‐four infants (77%) had a patent ductus arteriosus (PDA). There was a weak inverse correlation between PAAT with mPAP (r = −0.35, P = 0.01), sPAP (r = −0.29, P = 0.03), and PVRi (r = −0.29, P = 0.03). Conclusion There is a weak inverse relationship between PAAT and pulmonary artery pressures. This relationship is less robust in our population of infants with a high incidence of PDAs compared to previous studies in older children. Thus, PAAT may be less clinically meaningful for diagnosing pulmonary arterial hypertension in infants, particularly those with PDAs.