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Aortopathy is characterized by vascular smooth muscle cell (VSMC) abnormalities and elastic fiber fragmentation. Elastin insufficient ( Eln) mice demonstrate latent aortopathy similar to human disease. We hypothesized that aortopathy manifests primarily in the aorto-pulmonary septal (APS) side of the thoracic aorta due to asymmetric cardiac neural crest (CNC) distribution. Anatomic (aortic root vs. ascending aorta) and molecular (APS vs. non-APS) regions of proximal aorta tissue were examined in adult and aged wild type (WT) and mutant ( Eln) mice. CNC, VSMCs, elastic fiber architecture, proteoglycan expression, morphometrics and biomechanical properties were examined using histology, 3D reconstruction, micropipette aspiration and in vivo magnetic resonance imaging (MRI). In the APS side of Eln aorta, Sonic Hedgehog (SHH) is decreased while SM22 is increased. Elastic fiber architecture abnormalities are present in the Eln aortic root and APS ascending aorta, and biglycan is increased in the aortic root while aggrecan is increased in the APS aorta. The Eln ascending aorta is stiffer than the aortic root, the APS side is thicker and stiffer than the non-APS side, and significant differences in the individual aortic root sinuses are observed. Asymmetric structure-function abnormalities implicate regional CNC dysregulation in the development and progression of aortopathy. [ABSTRACT FROM AUTHOR]

Background: Children with advanced chronic kidney disease (CKD) frequently develop left ventricular (LV) hypertrophy. The extent of hypertrophy that results in cardiac dysfunction is unknown. Systolic function, routinely determined by ejection fraction (EF), is usually preserved in these patients. However, a decrease in EF represents an advanced cardiac dysfunction. We used cardiac magnetic resonance (CMR) and phosphorus-31 MR spectroscopy (31P MRS) to assess markers of cardiac dysfunction in young CKD patients. Methods: Ten dialysis and ten post-transplant patients completed the study. The outcomes were peak LV myocardial circumferential strain (Ecc); myocardial T2 relaxation time and full width at half maximum (FWHM) of T2 distribution; and phosphocreatinine/adenosine triphosphate (PCr/ATP) to measure muscle energy metabolism. Healthy controls were used for comparison. Results: All patients had normal EF; nine (45%) had low Ecc. Ecc was lower in dialysis versus transplant ( p < 0.0001) patients and inversely correlated with LV mass index, r = −0.47, p = 0.04. Patients had higher T2 ( p = 0.056) and FWHM ( p = 0.01) than controls. T2 levels were positively correlated with LVM index ( r = 0.46, p = 0.04). PCr/ATP was lower in patients than in controls ( p = 0.02). Conclusion: Young patients with advanced CKD and normal EF have early cardiac changes. Association of these abnormalities with increased left ventricular mass (LVM) index suggests development of maladaptive hypertrophy. [ABSTRACT FROM AUTHOR]

The cardiac disease ubiquitously associated in Duchenne Muscular Dystrophy (DMD) has traditionally been considered a progressive dilated cardiomyopathy (DCM). However, left ventricular (LV) dilatation as measured with cardiac MRI has not been a consistent finding in this population, even as circumferential strain (ε) declines with advancing disease. We hypothesized that a distinct pattern of changes in LV geometry, during the course of ε decline, distinguishes DMD associated heart disease from DCM. Using CMR, LV end-diastolic volume (EDV), mass (LVM), ejection fraction, ε and myocardial delayed enhancement (MDE) were determined in DMD patients and normal control subjects. The LV Remodeling Index (LVRI) was calculated as the ratio of LV Mass to Volume (LVM/EDV). Statistical comparisons between all LV parameters and genotype were also performed. Median LVRI in DMD (n = 127) and control subjects (n = 41) were different (0.75 vs. 0.65, P = 0.0150) but within normal range. Furthermore, the median LVRI in DMD boys with reduced LV systolic function was significantly reduced compared to those with normal LV systolic function (0.64 vs. 0.75, P = 0.0974). However, the presence of MDE was associated with a lower median LVRI (0.57 vs. 0.76, P = 0.0471). Regression analysis showed no significant correlation between ε and LVRI (r = −0.03). The LVRI of DMD patients is unexpectedly normal and not correlated with ε Based on these findings, DMD-associated heart disease exhibits a unique remodeling pattern distinct from DCM. [ABSTRACT FROM AUTHOR]

The ability of the phase-sensitive steady-state free precession (SSFP) technique to distinguish subcutaneous and visceral adipose tissue in the abdomen at 3 T was evaluated. A phased array receiver radiofrequency coil and a commercially available SSFP sequence were used for imaging. The raw image data were postprocessed to generate fat-only and water-only images. A postprocessing algorithm that is computationally efficient and robust is presented. The postprocessing technique separates the fat and water pixels automatically without any user interference. The feasibility of the technique is demonstrated in vivo with breath-hold abdomen images. The short scan time and the ease of use of this technique are well suited to the quantification of body fat distribution in children. [ABSTRACT FROM AUTHOR]

Steady-state free precision techniques are often used in cine cardiac MRI, but are highly susceptible to off-resonance artifacts. In this article, we review the types and prevalence of off-resonance artifacts in the left ventricle on a 3 T MR scanner and describe the implementation of a technique to mitigate these artifacts. A group of 16 healthy children underwent SSFP cine imaging in the short axis. The synthesizer frequency was adjusted after scouting for the optimal frequency in a series of SSFP images with different frequency shifts. A total of 136 short-axis slices were examined for artifacts after the frequency adjustment. A significant number of slices in the apex region contained dark bands, flow artifacts and/or bright out-of-plane coherent artifacts. However, only five slices (3.6%) had artifacts that were detrimental to the accurate detection of myocardial boundaries. This technique offers a fast and easy way to suppress off-resonance artifacts in SSFP imaging at 3 T. [ABSTRACT FROM AUTHOR]