Kan Hor

Cardiovascular Anomalies in Turner Syndrome: Spectrum, Prevalence, and Cardiac MRI Findings in a Pediatric and Young Adult Population

OBJECTIVEnTurner syndrome affects one in 2,500 girls and women and is associated with cardiovascular anomalies. Visualizing the descending thoracic aorta in adults with Turner syndrome with echocardiography is difficult. Therefore, cardiac MRI is the preferred imaging modality for surveillance. Our goals were to use cardiac MRI describe the spectrum and frequency of cardiovascular abnormalities and to evaluate aortic dilatation and associated abnormalities in pediatric patients with Turner syndrome.nnnMATERIALS AND METHODSnThe cases of 51 patients with Turner syndrome (median age, 18.4 years; range, 6-36 years) were evaluated with cardiac MRI. The characteristics assessed included aortic structure, elongation of the transverse aortic arch, aortic diameter at multiple locations, and coarctation of the aorta (CoA). Additional evaluations were made for presence of bicuspid aortic valve (BAV), and partial anomalous pulmonary venous return (PAPVR). Associations between the cardiac MRI data and the following factors were assessed: age, karyotype, body surface area, blood pressure, and ventricular sizes and function.nnnRESULTSnSixteen patients (31.4%) had elongation of the transverse aortic arch, eight (15.7%) had CoA, 20 (39.2%) had BAV, and eight (15.7%) had PAPVR. Aortic dilatation was most common at the aortic sinus (30%). Elongation of the transverse aortic arch was associated with CoA (p < 0.01) and BAV (p < 0.05). Patients with elongation of the transverse aortic arch had dilated aortic sinus (p < 0.05). Patients with PAPVR had increased right heart mass (p < 0.05), increased ratio of main pulmonary artery to aortic valve blood flow (p = 0.0014), and increased right ventricular volume (p < 0.05).nnnCONCLUSIONnCardiovascular anomalies in pediatric patients with Turner syndrome include aortic abnormalities and PAPVR. The significant association between elongation of the transverse aortic arch and CoA, BAV, and aortic sinus dilatation may contribute to increased risk of aortic dissection. The presence of PAPVR can be hemodynamically significant. These findings indicate that periodic cardiac MRI screening of persons with Turner syndrome is beneficial.

Early cardiac dysfunction in pediatric patients on maintenance dialysis and post kidney transplant

BackgroundChildren 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.MethodsTen 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.ResultsAll patients had normal EF; nine (45%) had low Ecc. Ecc was lower in dialysis versus transplant (pu2009<u20090.0001) patients and inversely correlated with LV mass index, ru2009=u2009−0.47, pu2009=u20090.04. Patients had higher T2 (pu2009=u20090.056) and FWHM (pu2009=u20090.01) than controls. T2 levels were positively correlated with LVM index (ru2009=u20090.46, pu2009=u20090.04). PCr/ATP was lower in patients than in controls (pu2009=u20090.02).ConclusionYoung 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.

Liquefaction necrosis of mitral annular calcification (LNMAC): review of pathology, prevalence, imaging and management: proposed diagnostic imaging criteria with detailed multi-modality and MRI image characterization

Liquefactive necrosis within a large spheroid zone of mitral annular calcification (LNMAC) is an atypical but increasingly recognized variant of mitral annular calcification (MAC). Proposed MRI, echo, and CT imaging criteria for diagnosis of this unusual disease entity are discussed along with a review of the prognosis, histopathology, and management implications. A comprehensive ECHO, CT, and MRI imaging approach to diagnostic differentiation from other cardiac masses, allowing characterization of the differing components of this unusual lesion is emphasized. Differentiation from surrounding myocardium, and demonstration of peripheral ring type hyperenhancement, or hyperintense signal in the wall of this lesion, seen with specific inversion recovery MRI sequences is presented as a major diagnostic criterion. The relationship of these MRI image findings to underlying pathology is also discussed. An illustrative case vignette is provided for clinical reference.

Energy Transfer Ratio as a Metric of Right Ventricular Efficiency in Repaired Congenital Heart Disease

OBJECTIVEnWith the success of early repair, continued functional assessment of repaired congenital heart disease is critical for improved long-term outcome. Pulmonary regurgitation, which is one of the main postoperative sequelae of congenital heart disease involved with the right ventricle (RV) such as tetralogy of Fallot and transposition of the great arteries, results in progressive RV dilatation coupled with pulmonary artery (PA) obstruction causing elevated RV pressures. The appropriate timing of intervention to correct these postoperative lesions remains largely subjective. In the present study, we evaluated an energy-based end point, namely energy transfer ratio (eMPA ), to assess the degree of RV and PA inefficiency in a group of congenital heart disease patients with abnormal RV-PA physiology.nnnMETHODSnEight patients with abnormal RV-PA physiology and six controls with normal RV-PA physiology were investigated using a previously validated technique that couples cardiac magnetic resonance imaging and invasive pressure measurements.nnnRESULTSnThe mean eMPA of the patient group (0.56 ± 0.33) was significantly lower (P <.04) than that of the control group (1.56 ± 0.85), despite the fact that the patient group had a significantly higher RV stroke work indexed to body surface area (RV SWI ) than the control group (0.205 ± 0.095 J/m(2) vs. 0.090 ± 0.038 J/m(2) ; P <.02).nnnCONCLUSIONnWe determined that the patients had inefficient RV-PA physiology due to a combination of RV dilatation with pulmonary regurgitation and RV outflow obstruction leading to an elevated end-systolic pressure. Using coupled magnetic resonance imaging and invasive pressure measurements, eMPA is determined to be a sensitive energy-based end point for measuring RV-PA efficiency. It may serve as a diagnostic end point to optimize timing of intervention.

Assessment of Myocardial Contractile Function Using Global and Segmental Circumferential Strain following Intracoronary Stem Cell Infusion after Myocardial Infarction: MRI Feature Tracking Feasibility Study.

Background. Magnetic resonance imaging (MRI) strain analysis is a sensitive method to assess myocardial function. Our objective was to define the feasibility of MRI circumferential strain (ε cc) analysis in assessing subtle changes in myocardial function following stem cell therapy. Methods and Results. Patients in the Amorcyte Phase I trial were randomly assigned to treatment with either autologous bone-marrow-derived stem cells infused into the infarct-related artery 5 to 11 days following primary PCI or control. MRI studies were obtained at baseline, 3, and 6 months. ε cc was measured in the short axis views at the base, mid and apical slices of the left ventricle (LV) for each patient (13 treatments and 10 controls). Mid-anterior LV ε cc improved between baseline −18.5 ± 8.6 and 3 months −22.6 ± 7.0, P = 0.03. There were no significant changes in ε cc at 3 months and 6 months compared to baseline for other segments. There was excellent intraobserver and interobserver agreement for basal and mid circumferential strain. Conclusion. MRI segmental strain analysis is feasible in assessment of regional myocardial function following cell therapy with excellent intra- and inter-observer variabilitys. Using this method, a modest interval change in segmental ε cc was detected in treatment group.

MRI strain analysis as a novel modality for the assessment of myocardial function following stem cell therapy-results from Amorcyte trial

Objective To evaluate MRI strain analysis for the assessment of myocardial function following stem cell therapy. Background MRI strain analysis is a novel way to assess myocardial function and may detect subtle improvements in myocardial function earlier than commonly used methods of myocardial function assessment. Stem cell therapy offers a promising approach to the regeneration of damaged vascular and cardiac tissue after myocardial infarction. Myocardial strain imaging has not been evaluated as an end point in stem cell studies. Our objective was to demonstrate the role and feasibility of MRI strain analysis for the early detection of myocardial functional improvement following stem cell therapy. Methods

A LONGITUDINAL EXAMINATION OF CARDIAC DYSFUNCTION IN PATIENTS WITH DUCHENNE AND BECKER MUSCULAR DYSTROPHY VIA CMRI

Duchenne and Becker muscular dystrophy (D/BMD) typically exhibit cardiac dysfunction, but the temporal evolution is not well understood. Evaluation of potential therapies for cardiac dysfunction in D/BMD patients requires accurate, quantitative, longitudinal data; therefore, our study examined the

Congenital Cardiology SolutionsLEFT VENTRICULAR NON-COMPACTION IN DUCHENNE MUSCULAR DYSTROPHY

Left ventricular non-compaction (LVNC) is characterized by regions with prominent, deep trabeculations in the left ventricular (LV) endocardium. Anecdotal data suggest an increased prevalence of LVNC in neuromuscular diseases including Duchenne Muscular Dystrophy (DMD). This study aims to define the

Serial assessment of myocardial T2 in Duchenne muscular dystrophy

Background Duchenne Muscular Dystrophy (DMD), a lethal X-linked skeletal and cardiac myopathy, affects 1/3500 males[1-2]. MRI studies have shown occult ventricular dysfunction and myocardial fibrosis in DMD patients. Previously we used the Full Width of Half Maximum (FWHM) of T2 distribution in LV to quantify the myocardial structural heterogeneity in DMD patients. In DMD subject groups, we showed that FWHM of the T2 histogram rose progressively with age and decreasing EF indicating that functional impairments could be associated with pre-existing abnormalities in tissue structure in young DMD patients. In this study we assessed the T2 distribution in DMD patients at two time points. We hypothesized that serial FWHM changes can be detected in individual DMD patients during a time when left ventricular ejection fraction (EF) changes are insignificant.

217 Normal human ventricular volume and mass values in children ages 5–10 years using steady state free precession MRI

Methods 50 healthy volunteer children (26 female) ages 5–10 years (mean age 7.7 years) underwent research CMR using steady-state free precession sequences in a Siemens 3 T Trio magnet. Children were allowed to watch video via a modified MRI-compatible display system (Avotec, Stuart, FL); no pharmacological sedation was used. Standard contiguous non-overlapping short-axis cine data sets from the ventricular apex to the base of the heart were performed both with breath holding and again during freebreathing. For the free-breathing component, the SSFP sequence was acquired with GRAPPA parallel acquisition (acceleration factor = 2); image blurring due to chest motion was suppressed by long term signal averaging (Nex = 4–5). Manual analysis was performed by 2 expert observers using Medis MASS (Leiden, Netherlands) software and the modified Simpsons rule to calculate LV and RV volumes and mass. Inter-observer variation was also assessed: 3 supplemental expert observers measured the LV and RV parameters on a randomly selected subset of 10 of the subjects (breath-holding sequences only); this data was compared per segment to the data generated on the same subjects by the initial 2 expert observers.