Publications (20)17.62 Total impact
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Article: Energy Transfer Ratio as a Metric of Right Ventricular Efficiency in Repaired Congenital Heart Disease.
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ABSTRACT: OBJECTIVE: With 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 (e(MPA) ), to assess the degree of RV and PA inefficiency in a group of congenital heart disease patients with abnormal RV-PA physiology. METHODS: Eight 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. RESULTS: The mean e(MPA) 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 SW(I) ) than the control group (0.205 ± 0.095 J/m(2) vs. 0.090 ± 0.038 J/m(2) ; P <.02). CONCLUSION: We 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, e(MPA) 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.Congenital Heart Disease 01/2013; · 0.90 Impact Factor -
Article: Serial assessment of myocardial T2 in Duchenne muscular dystrophy
Journal of Cardiovascular Magnetic Resonance 04/2012; 13:1-1. · 3.72 Impact Factor -
Article: Early cardiac dysfunction in pediatric patients on maintenance dialysis and post kidney transplant.
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ABSTRACT: 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. 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. 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). 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.Pediatric Nephrology 02/2012; 27(7):1157-64. · 2.52 Impact Factor -
Article: 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.
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ABSTRACT: 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.The international journal of cardiovascular imaging 08/2011; 28(5):1161-71. · 2.15 Impact Factor -
Article: Cardiovascular anomalies in Turner syndrome: spectrum, prevalence, and cardiac MRI findings in a pediatric and young adult population.
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ABSTRACT: Turner 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. The 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. Sixteen 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). Cardiovascular 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.American Journal of Roentgenology 02/2011; 196(2):454-60. · 2.78 Impact Factor -
Article: Presence of mechanical dyssynchrony in Duchenne Muscular dystrophy: a cardiac MRI study utilizing cross correlation delay
Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: MRI strain analysis as a novel modality for the assessment of myocardial function following stem cell therapy-results from Amorcyte trial
Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: Right ventricular strain in patients with tetralogy of Fallot
Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: Effects of steroids and angiotensin converting enzyme inhibition on circumferential strain in boys with duchenne muscular dystrophy: a cross-sectional and longitudinal study utilizing cardiac magnetic resonance imaging
Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: Serial assessment of myocardial T2 in Duchenne muscular dystrophy
Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: Presence of mechanical dyssynchrony in duchenne muscular dystrophy
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ABSTRACT: Abstract Background Cardiac dysfunction in boys with Duchenne muscular dystrophy (DMD) is a leading cause of death. Cardiac resynchronization therapy (CRT) has been shown to dramatically decrease mortality in eligible adult population with congestive heart failure. We hypothesized that mechanical dyssynchrony is present in DMD patients and that cardiovascular magnetic resonance (CMR) may predict CRT efficacy. Methods DMD patients (n = 236) were stratified into 4 groups based on age, diagnosis of DMD, left ventricular (LV) ejection fraction (EF), and presence of myocardial fibrosis defined as positive late gadolinum enhancement (LGE) compared to normal controls (n = 77). Dyssynchrony indices were calculated based on timing of CMR derived circumferential strain (ecc). The calculated indices included cross-correlation delay (XCD), uniformity of strain (US), regional vector of variance (RVV), time to maximum strain (TTMS) and standard deviation (SD) of TTMS. Abnormal XCD value was defined as > normal + 2SD. US, RVV, TTMS and SD were calculated for patients with abnormal XCD. Results There was overall low prevalence of circumferential dyssynchrony in the entire DMD population; it increased to 17.1% for patients with abnormal EF and to 31.2% in the most advanced stage (abnormal EF with fibrosis). All but one DMD patient with mechanical dyssynchrony exhibited normal QRS duration suggesting absence of electrical dyssynchrony. The calculated US and RVV values (0.91 ± 0.09, 1.34 ± 0.48) indicate disperse rather than clustered dyssynchrony. Conclusion Mechanical dyssynchrony is frequent in boys with end stage DMD-associated cardiac dysfunction. It is associated with normal QRS complex as well as extensive lateral fibrosis. Based on these findings, it is unlikely that this patient population will benefit from CRT.Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: Prediction and perinatal management of severely restrictive atrial septum in fetuses with critical left heart obstruction: clinical experience using pulmonary venous Doppler analysis.
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ABSTRACT: Up to 20% of fetuses with critical left heart obstructive lesions have highly restrictive or intact atrial septae. Although this condition is generally tolerated in utero, severe hypoxemia requiring emergency atrial septostomy often develops in newborns with restrictive atrial septum. We have reported that a pulmonary venous Doppler forward/reverse time-velocity integral ratio less than 5 is highly predictive of the need for emergency atrial septostomy. We reviewed our subsequent experience using fetal pulmonary venous Doppler patterns to identify and manage fetuses with critical left heart obstruction and suspected restrictive atrial septum. A retrospective review of neonates with a prenatal diagnosis of critical left heart obstruction was performed. Fetal restrictive atrial septum was defined as a small/absent interatrial shunt on 2-dimensional imaging and a mean forward/reverse time-velocity integral ratio of 5 or less. Available serial pulmonary venous Doppler data were reviewed. The primary outcome was postnatal confirmation of restrictive atrial septum or severe left atrial hypertension. Eight of 39 infants had a forward/reverse time-velocity integral ratio of 5 or less. A restrictive atrial septum was confirmed postnatally in 6 of 8 infants. Overall, a forward/reverse time-velocity integral ratio of 5 or less had a sensitivity of 100% and specificity of 94% for emergency atrial septostomy. Lowering the cutoff value to 3 or less would have eliminated false-positive diagnoses in the current series. Serial data demonstrated that late second trimester values did not change in later gestation with respect to either threshold in 30 of 32 fetuses. In the fetus with critical left heart obstruction, a threshold forward/reverse time-velocity integral ratio of 3 or less optimizes specificity for predicting emergency atrial septostomy. Most late second trimester values will not change over time with regard to threshold levels.The Journal of thoracic and cardiovascular surgery 12/2010; 141(4):988-94. · 3.41 Impact Factor -
Article: Circumferential strain analysis reveals occult cardiac dysfunction in palliated single ventricle patients
Journal of Cardiovascular Magnetic Resonance. 01/2010; -
Article: Left ventricular T2 distribution in Duchenne Muscular Dystrophy
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ABSTRACT: Abstract Background Although previous studies have helped define the natural history of Duchenne Muscular Dystrophy (DMD)-associated cardiomyopathy, the myocardial pathobiology associated with functional impairment in DMD is not yet known. The objective of this study was to assess the distribution of transverse relaxation time (T2) in the left ventricle (LV) of DMD patients, and to determine the association of myocardial T2 heterogeneity to the severity of cardiac dysfunction. DMD patients (n = 26) and normal control subjects (n = 13) were studied by Cardiovascular Magnetic Resonance (CMR). DMD subject data was stratified based on subject age and LV Ejection Fraction (EF) into the following groups: A (<12 years old, n = 12); B (≥12 years old, EF ≤ 55%, n = 8) and C (≥12 years old, EF = 55%, n = 6). Controls were also stratified by age into Groups N1 (<12 years, n = 6) and N2 (>12 years, n = 5). LV mid-slice circumferential myocardial strain (ε<sub>cc</sub>) was calculated using tagged CMR imaging. T2 maps of the LV were generated for all subjects using a black blood dual spin echo method at two echo times. The Full Width at Half Maximum ( FWHM ) was calculated from a histogram of LV T2 distribution constructed for each subject. Results In DMD subject groups, FWHM of the T2 histogram rose progressively with age and decreasing EF (Group A FWHM = 25.3 ± 3.8 ms; Group B FWHM = 30.9 ± 5.3 ms; Group C FWHM = 33.0 ± 6.4 ms). Further, FWHM was significantly higher in those with reduced circumferential strain (|ε<sub>cc</sub>| ≤ 12%) (Group B, and C) than those with |ε<sub>cc</sub>| > 12% (Group A). Group A FWHM was not different from the two normal groups (N1 FWHM = 25.3 ± 3.5 ms; N2 FWHM = 24.0 ± 7.3 ms). Conclusion Reduced EF and ε<sub>cc </sub>correlates well with increased T2 heterogeneity quantified by FWHM , indicating that subclinical functional impairments could be associated with pre-existing abnormalities in tissue structure in young DMD patients.Journal of Cardiovascular Magnetic Resonance. 01/2010; -
Article: Increased susceptibility of the left lateral free wall to myocardial delayed enhancement in Duchenne Muscular Dystrophy: progressive systolic dysfunction demonstrable by CMR regional strain analysis
Journal of Cardiovascular Magnetic Resonance. 01/2009; -
Article: Left ventricular T2 distribution in Duchenne Muscular Dystrophy
Journal of Cardiovascular Magnetic Resonance. 01/2009; -
Article: Novel technique of strain assessment utilizing feature tracking in nontagged SSFP images: validation with tagged strain analysis
Journal of Cardiovascular Magnetic Resonance. 01/2009; -
Article: Late gadolinium enhancement: precursor to cardiomyopathy in Duchenne muscular dystrophy?
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ABSTRACT: Progressive cardiomyopathy is a common cause of death in Duchenne muscular dystrophy (DMD), presumably secondary to fibrosis of the myocardium. The posterobasal and left lateral free wall of the left ventricle (LV) are initial sites of myocardial fibrosis pathologically. The purposes of this study were to assess whether cardiac magnetic resonance imaging (CMRI), utilizing late gadolinium enhancement (LGE), could identify fibrosis in selective areas of the myocardium, and to assess the relationship of the presence and extent of fibrosis to LV function. The cardiology databases at Primary Children's Medical Center and Cincinnati Children's Hospital Medical Center were reviewed to identify patients with DMD who had undergone a CMRI within the last 2 years. Age, LV ejection fraction, LV mass, presence and location of LGE were documented. Volumes were measured using MASS (Medis, Inc.) to calculate ejection fraction and mass. LGE images were acquired and when positive, customized computer assisted sizing of the areas of late gadolinium enhancement were performed on all slices. Normal function was defined as LV ejection fraction >54%. A total of 74 patients with DMD had complete data sets (median age 13.7 years, range 7.7-26.4). Twenty-four patients (32%) had LGE involving the posterobasal region of the LV in a sub-epicardial distribution. Those patients with more involvement had spread to the inferior and left lateral free wall with progressive transmural fibrous replacement. There was relative sparing of the interventricular septum and right ventricle. Patients with LGE were significantly older than those without (mean age 16.4 vs 12.9 years, P < 0.001). LGE was positively associated with BSA-adjusted LV mass, LV end-diastolic volume, LV end-systolic volume, and RV end-systolic volume but inversely correlated with ejection fraction of the LV (P < 0.001) and RV (P = 0.004). LGE by CMRI is able to detect fibrosis in selective regions of myocardium in patients with DMD. Unfavorable LV remodeling, with a corresponding decreased ejection fraction, is associated with the presence of LGE. Serial studies are warranted to determine if LGE precedes a decrease in function, and if early medical management is useful in preventing progression once LGE is documented.The international journal of cardiovascular imaging 08/2008; 25(1):57-63. · 2.15 Impact Factor -
Article: 217 Normal human ventricular volume and mass values in children ages 5–10 years using steady state free precession MRI
Journal of Cardiovascular Magnetic Resonance. 01/2008; -
Article: 1071 Interobserver variability differences for cardiac MRI right ventricular (RV) volumetry and mass measures between standard and "modified" right ventricular short axis imaging in patients with chronic pulmonary insufficiency
Journal of Cardiovascular Magnetic Resonance. 01/2008;
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2011
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Fresno Surgical Hospital
Fresno, CA, USA
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2008
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Cincinnati Children's Hospital Medical Center
Cincinnati, OH, USA
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