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We sought to determine whether global and regional left ventricular (LV) strain parameters were altered in repaired coarctation of the aorta (COA) with normal LV ejection fraction (EF) when compared with healthy adult controls, and whether such alterations were related to LV hypertrophy (LVH). We identified 81 patients after COA repair (31 female, age 25 ± 8.5 years) with inclusion criteria at follow-up CMR of: age ≥13 years, time post-repair ≥10 years, no aortic valve disease, LV-EF >50%). LV deformation indices derived using CMR-feature tracking and volumetric EF were compared between COA patients and normal controls (n = 20, 10 female, age 37 ± 7 years), and between COA with versus without LVH. In repaired COA versus controls, LV-EF (%) was 62 ± 7.2 versus 58 ± 3.0 (p = 0.01), and LV mass (g/m(2)) 66 ± 16.8 versus 57.7 ± 6.0 (p = 0.0001). LV global longitudinal strain (GLS) was decreased to -17.0 ± 4.7% in COA (-20 ± 5% in controls, p = 0.02), and global radial strain (GRS) reduced to 40 ± 15% (50 ± 12.4% in controls, p = 0.003). The global circumferential strain (GCS) was preserved in COA at -23 ± 4.7% (-24.6 ± 2.4% in controls, p = 0.14). Regionally, LS decrease was marked in the basal segments (septal, p = 0.005, lateral, p = 0.013). In COA with LVH (n = 45, mass 76.3 ± 12.8 g/m(2)) versus without LVH (n = 36, mass 52.2 ± 10 g/m(2)), GLS was more markedly decreased (-15.7 ± 4.8 vs. -18.5 ± 4.2%, p = 0.016, but GRS and GCS were similar (p = 0.49 and 0.27). In post-repair COA with normal LV-EF, GLS and GRS are reduced whilst GCS is preserved. GLS reduction is more pronounced in the presence of LVH. GLS may qualify as indicator of early LV dysfunction.

Objective: Pulmonary venous pathway obstruction (PVPO) is a serious complication of the atrial switch procedure for transposition of the great arteries (TGA). Redistribution of pulmonary arterial blood flow may make conventional echocardiographic measures of unilateral PVPO difficult to interpret. Previous studies have demonstrated altered arterial flow patterns using phase-contrast magnetic resonance imaging (PC-MRI). The purpose of this study was to investigate arterial flow patterns in the setting of unilateral PVPO following the Mustard operation., Methods: We retrospectively reviewed the arterial flow patterns of 12 patients undergoing magnetic resonance imaging between 2006 and 2011 who had had the Mustard operation., Results: Three patients had left PVPO and all showed >65% flow distributed to the right pulmonary artery (RPA). One had severe obstruction and was the only one to show significant continuous diastolic forward flow in the RPA or diastolic flow reversal in the left pulmonary artery., Conclusion: RPA/left pulmonary artery flow ratio appears to be a sensitive marker for PVPO. In the absence of pulmonary regurgitation, reversed diastolic flow in the ipsilateral and continuous in the contralateral pulmonary artery appears specific for severe obstruction. Branch pulmonary artery phase-contrast magnetic resonance imaging (PC-MRI) should be performed routinely for patients who have had an atrial switch for transposition of the great arteries., (© 2012 Wiley Periodicals, Inc.)

Background: Cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) is a recently described method of post processing routine cine acquisitions which aims to provide quantitative measurements of circumferentially and radially directed ventricular wall strain. Inter-study reproducibility is important for serial assessments however has not been defined for CMR-FT., Methods: 16 healthy volunteers were imaged 3 times within a single day. The first examination was performed at 0900 after fasting and was immediately followed by the second. The third, non-fasting scan, was performed at 1400.CMR-FT measures of segmental and global strain parameters were calculated. Left ventricular (LV) circumferential and radial strain were determined in the short axis orientation (Ecc(SAX) and Err(SAX) respectively). LV and right ventricular longitudinal strain and LV radial strain were determined from the 4-chamber orientation (Ell(LV), Ell(RV), and Err(LAX) respectively). LV volumes and function were also analysed.Inter-study reproducibility and study sample sizes required to demonstrate 5% changes in absolute strain were determined by comparison of the first and second exams. The third exam was used to determine whether diurnal variation affected reproducibility., Results: CMR-FT strain analysis inter-study reproducibility was variable. Global strain assessment was more reproducible than segmental analysis. Overall Ecc(SAX) was the most reproducible measure of strain: coefficient of variation (CV) 38% and 20.3% and intraclass correlation coefficient (ICC) 0.68 (0.55-0.78) and 0.7 (0.32-0.89) for segmental and global analysis respectively. The least reproducible segmental measure was Ell(RV): CV 60% and ICC 0.56 (0.41-0.69) whilst the least reproducible global measure was Err(LAX): CV 33.3% and ICC 0.44 (0-0.77). Variable reproducibility was also reflected in the calculated sample sizes, which ranged from 11 (global Ecc(SAX)) to 156 subjects (segmental Ell(RV)). The reproducibility of LV volumes and function was excellent. There was no diurnal variation in global strain or LV volumetric measurements., Conclusions: Inter-study reproducibility of CMR-FT varied between different parameters, as summarized above and was better for global rather than segmental analysis. It was not measurably affected by diurnal variation. CMR-FT may have potential for quantitative wall motion analysis with applications in patient management and clinical trials. However, inter-study reproducibility was relatively poor for segmental and long axis analyses of strain, which have yet to be validated, and may benefit from further development.

Background: Systemic-to-pulmonary collateral flow (SPCF) may constitute a risk factor for increased morbidity and mortality in patients with single-ventricle physiology (SV). However, clinical research is limited by the complexity of multi-vessel two-dimensional (2D) cardiovascular magnetic resonance (CMR) flow measurements. We sought to validate four-dimensional (4D) velocity acquisition sequence for concise quantification of SPCF and flow distribution in patients with SV., Methods: 29 patients with SV physiology prospectively underwent CMR (1.5 T) (n = 14 bidirectional cavopulmonary connection [BCPC], age 2.9 ± 1.3 years; and n = 15 Fontan, 14.4 ± 5.9 years) and 20 healthy volunteers (age, 28.7 ± 13.1 years) served as controls. A single whole-heart 4D velocity acquisition and five 2D flow acquisitions were performed in the aorta, superior/inferior caval veins, right/left pulmonary arteries to serve as gold-standard. The five 2D velocity acquisition measurements were compared with 4D velocity acquisition for validation of individual vessel flow quantification and time efficiency. The SPCF was calculated by evaluating the disparity between systemic (aortic minus caval vein flows) and pulmonary flows (arterial and venour return). The pulmonary right to left and the systemic lower to upper body flow distribution were also calculated., Results: The comparison between 4D velocity and 2D flow acquisitions showed good Bland-Altman agreement for all individual vessels (mean bias, 0.05 ± 0.24 l/min/m2), calculated SPCF (-0.02 ± 0.18 l/min/m2) and significantly shorter 4D velocity acquisition-time (12:34 min/17:28 min,p < 0.01). 4D velocity acquisition in patients versus controls revealed (1) good agreement between systemic versus pulmonary estimator for SPFC; (2) significant SPCF in patients (BCPC 0.79 ± 0.45 l/min/m2; Fontan 0.62 ± 0.82 l/min/m2) and not in controls (0.01 + 0.16 l/min/m2), (3) inverse relation of right/left pulmonary artery perfusion and right/left SPCF (Pearson = -0.47,p = 0.01) and (4) upper to lower body flow distribution trend related to the weight (r = 0.742, p < 0.001) similar to the controls., Conclusions: 4D velocity acquisition is reliable, operator-independent and more time-efficient than 2D flow acquisition to quantify SPCF. There is considerable SPCF in BCPC and Fontan patients. SPCF was more pronounced towards the respective lung with less pulmonary arterial flow suggesting more collateral flow where less anterograde branch pulmonary artery perfusion.

Purpose: To evaluate the MR agreement of cardiac function parameters between volumetric (cine SSFP) and phase contrast flow (PC-flow) assessment in patients with repaired tetralogy of Fallot (r-TOF) and chronic pulmonary regurgitation (PR) at rest and under dobutamine stress (DS-MR)., Materials and Methods: We studied 18 patients with r-TOF and severe chronic PR (34 ± 12.7 years, PR fraction([flow]) 44 ± 15%) by cardiac MR at rest, 10 and 20 μg/kg/min of dobutamine. We compared analogous functional parameters by volumetry and PC-flow: (i) Systemic output [left ventricle stroke volume (LV(SV)) versus aortic forward flow (AO(FF))], (ii) Pulmonary output [right ventricle stroke volume (RV(SV)) versus pulmonary forward flow (PA(FF))], (iii) PR volume [(RV(SV)-LV(SV)) versus pulmonary backward flow (PA(BF))], (iv) PR fraction [(RV(SV)-LV(SV)/RV(SV)) versus (PA(BF)/PA(FF))]., Results: We found excellent Bland-Altman agreement (mean difference ± limits of agreement, mL/beat/m(2)) at rest for both the systemic (-0.8 ± 5.7) and pulmonary strokes volumes (-0.1 ± 7.6), which slightly deteriorates during DS-MR. The PR volume showed acceptable agreement at rest (-3.6 ± 15.1), but also further deteriorated during stress (5.4 ± 24). In contrast, the PR fraction showed poor agreement equally at rest (-5.6 ± 22.8) and DS-MR (3.2 ± 19.2)., Conclusion: In r-TOF with chronic PR, analogous functional parameters should not be used interchangeably between volumetric and PC-flow assessment during DS-MR evaluation., (Copyright © 2011 Wiley-Liss, Inc.)

Purpose: To provide reference data for atrial size and function during childhood and adolescence by cardiac MR (CMR)., Materials and Methods: We prospectively examined 115 healthy children and adolescents (mean age, 12.4 ± 4.1 years; range, 4.4-20.3 years) by CMR using a stack of standard two-dimensional steady-state free-precession slices acquisition covering the whole heart in transverse plane. Maximal and minimal volumes of both atria and their respective calculated cyclic volume change (CVC) and emptying fraction (EMF) were determined and reference centile curves were computed (lambda-mu-sigma [LMS]-method)., Results: Gender differences were noted for atrial volumes and derived parameters. Maximal right atrial (RA) volume for girls was 53.3 ± 11.8 mL/m(2) and 58.1 ± 15.7 for boys (P = 0.064), minimal RA volume for girls/boys was 23.2 ± 6.2/27.0 ± 7.9 mL/m(2) (P = 0.004). Maximal left atrial (LA) volume for girls/boys was 44.2 ± 8.7/46.7 ± 10.1 mL/m(2) (P = 0.143) and minimal LA volume for girls/boys was 19.2 ± 3.9/21.5 ± 5.1 mL/m(2) (P = 0.009). For both atria, CVC was higher for boys, but EMF higher for girls. Percentiles of RA/LA volumes showed steeper increase in boys than in girls, who in fact showed a plateau after age 14., Conclusion: Pediatric sex-specific reference centiles are provided to improve clinical interpretation and facilitate future research involving CMR-derived atrial function., (Copyright © 2011 Wiley-Liss, Inc.)

Objectives: To evaluate the current disagreement between the gold standard X-ray angiography (XRA) and magnetic resonance angiography (MRA) for the measurement of peripheral pulmonary artery stenosis (PPAS)., Background: MRA may help planning of catheter interventions for PPAS. However, there are sources of disagreement between XRA and MRA as measures are performed differently. We hypothesized that agreement may improve if identical angulation views are used., Methods: In this retrospective study, 17 patients were included. Four independent observers analyzed the pictures in three technique modalities: (1) XRA, (2) cross-sectional-MRA: reformatted to obtain the perpendicular cut-off view of the vessel, and (3) angulated-MRA: reformatted using the same angulations used in XRA. We measured: (a) minimal diameter at stenosis, (b) vessel diameter 1 cm proximal, and (c) 1 cm distal to the stenosis., Results: While in elliptical vessels cross-sectional-MRA provided both the larger and smaller diameter, XRA and angulated-MRA typically provided only the larger diameter due to projections. We found poor agreement between the smaller diameter in cross-sectional-MRA and XRA. XRA underestimate the diameter at the three locations (<15-22%). However, there was a good agreement between the larger cross-sectional-MRA diameter and XRA. This further improved if MRA images were reformatted with the identical angulations used in XRA (angulated-MRA)., Conclusions: Conventional cross-sectional-MRA measurements of PPAS only moderately agree with XRA. However, using identical angulations in MRA reduces the bias. Hence, MRA is a valuable tool for planning angulations and measurements of PPAS prior to catheter interventions., (Copyright © 2010 Wiley-Liss, Inc.)

The case of an 8-year-old girl with atrial septal defect and associated anomalous pulmonary venous return is presented to illustrate the advantages of four dimensional flow (4D flow) over the current two dimensional flow (2D flow) in terms of time efficiency, easy planning, accurate and individual quantification of the blood sources contributing to the left-to-right shunting from one single acquisition, internal validation of flow measurement accuracy, possibility of reanalysis without rescanning in case of unexpected findings during the postprocessing, and comprehensive understanding of flow insight by use of particle tracing visualization.

Aims: We aimed to assess interventricular and right-intraventricular dyssynchrony in patients after tetralogy of Fallot (TOF) repair by two-dimensional (2D) speckle tracking and to identify factors associated with dyssynchrony., Methods and Results: Forty-two patients after TOF repair with a mean age of 19.8 years and 42 age-matched healthy controls were studied. Longitudinal myocardial deformation (strain) and time-to-peak intervals were assessed by 2D speckle tracking and tissue Doppler imaging (TDI) in an apical four-chamber view. Dyssynchrony was defined as delay above 3 standard deviations of mean values in the control group. Magnetic resonance imaging (MRI) was performed for evaluation of ventricular function. Using 2D speckle tracking, 22 patients (52%) showed interventricular dyssynchrony and 16 (38%) had right-intraventricular dyssynchrony. The interventricular delay correlated significantly with right ventricular (RV) strain (r = 0.687, P < 0.001), RV systolic pressure (r = 0.535, P = 0.001), QRS duration (r = 0.466, P = 0.002), RV end-diastolic (r = 0.377, P = 0.018), and RV end-systolic volumes (r = 0.452, P = 0.004) as well as RV ejection fraction (r = -0.378, P = 0.018). Similarly, the right-intraventricular delay correlated significantly with RV strain (r = 0.534, P < 0.001), QRS duration (r = 0.428, P = 0.005), RV end-systolic volume (r = 0.34, P = 0.038), and RV systolic pressure (r = 0.413, P = 0.015). In multivariate regression analysis, reduced RV strain and prolonged QRS duration remained the main determinant factors predicting dyssynchrony. Moreover, 2D speckle tracking and TDI showed a significant correlation in the assessment of the interventricular (r = 0.738, P < 0.001) and right-intraventricular delay (r = 0.747, P < 0.001)., Conclusion: Interventricular and right-intraventricular dyssynchrony are detectable in patients after TOF repair by 2D speckle tracking. Reduced RV myocardial deformation and QRS prolongation are the main factors associated with the observed dyssynchrony.

The atria play an important role in cardiac performance. We evaluated their function and the atrioventricular interaction in operated patients with tetralogy of Fallot (TOF). Twenty patients who had undergone surgical repair of TOF and seven controls were investigated. Patients had residual pulmonary but no major tricuspid valve insufficiency. Atrial and ventricular strain rates were obtained by echocardiographic speckle tracking. Cine MRI-derived volumetric analysis provided atrial and ventricular time volume and time volume change curves yielding emptying and filling parameters. In addition, at the atrial level, reservoir, conduit and pump function, and cyclic volume change were calculated. At the atrioventricular valve level, tricuspid and mitral annular plane systolic excursion (TAPSE and MAPSE, respectively) were measured by two-dimensional echocardiography. In the patients compared with controls, right ventricular end-diastolic volumes were increased and biventricular ejection fraction was decreased (all P < 0.05). Biventricular measures of early diastolic ventricular filling were at control levels, but in late diastole, right ventricular filling parameters and strain rates were decreased (P < 0.001). The maximal right atrial size was slightly but not significantly diminished, but cyclic volume change was significantly reduced (P < 0.0001). Pump and reservoir function were decreased (P < 0.05), and conduit function was elevated (P < 0.001). The left atrium showed reduced reservoir function and cyclic volume change (P < 0.05). TAPSE and MAPSE were also decreased (P < 0.05). There were statistically significant interdependencies between RV ejection fraction, TAPSE, and right atrial filling and emptying parameters (all P < 0.05). In TOF patients, moderate systolic and diastolic right ventricular dysfunction is associated with clearly impaired right atrial function. The left atrium is affected to a lesser extent.

Purpose: To investigate the impact of interinstitutional variance (=interobserver variance between institutions) for volumetric and flow cardiac MR (CMR) data and if training on image reading could improve bias., Materials and Methods: In a three-center study, a total of 32 adults with repaired Tetralogy of Fallot and 23 controls underwent CMR using standardized protocols for ventricular volumes/mass (by transverse and short-axis cine-MRI) and pulmonary/aortic blood flow by velocity-encoded MRI (VEC-MRI). Data were analyzed blinded and independently in each institution by experienced readers. Interinstitutional variance was determined before/after training on consented guidelines for image analysis., Results: In patients, initial interinstitutional variability of right ventricular parameters was substantial but decreased by training. On transverse planes, variation coefficient for end-diastolic/systolic volumes and ejection fraction decreased from 22%, 19%, and 19% to 7%, 10%, and 8%, respectively (P < 0.025). Left-ventricular variation coefficients improved for end-diastolic and stroke volumes from 8% and 15% to 4% and 6%, respectively (P < 0.007). For short-axis volumetry training resulted in narrowed limits of confidence. Variability did not significantly change in the controls. There was no significant difference between transverse/short-axis MRI. Interinstitutional variance for VEC-MRI in patients/controls was low (<4%)., Conclusion: Interinstitutional variance is an important source of variability in volumetric but not in flow CMR. Such variance can be reduced effectively by consented training.

Four-dimensional (4D) flow imaging has been used to study flow patterns and pathophysiology, usually focused on specific thoracic vessels and cardiac chambers. Whole-heart 4D flow at high measurement accuracy covering the entire thoracic cardiovascular system would be desirable to simplify and improve hemodynamic assessment. This has been a challenge because compensation of respiratory motion is difficult to achieve, but it is paramount to limit artifacts and improve accuracy. In this work we propose a self-gating technique for respiratory motion-compensation integrated into a whole-heart 4D flow acquisition that overcomes these challenges. Flow components are measured in all three directions for each pixel over the complete cardiac cycle, and 1D volume projections are obtained at certain time intervals for respiratory gating in real time during the acquisition. The technique was tested in 15 volunteers, in which stroke volumes (SVs) in the great arteries showed excellent agreement with standard 2D phase-contrast (PC) scans. In contrast, nongated 4D flow with two averages had substantial disagreement with 2D flow. Applied to patients with congenital cardiac left-to-right shunting, the precision of flux data was highly beneficial. The methodology presented here has the potential to allow a complete study of flow pathophysiology of the thoracic cardiovascular system from a single free-breathing scan., ((c) 2009 Wiley-Liss, Inc.)

Purpose: To determine the value of whole-heart three-dimensional magnetic resonance imaging (MRI) for coronary artery imaging in children/adolescents with congenital heart disease (CHD)., Materials and Methods: Forty children/adolescents (median age: 14 years, range 2.6-25.8) with CHD underwent free-breathing navigator-gated isotropic three-dimensional steady-state free-precession (3D-SSFP) MRI for cardiac morphology. Two observers independently evaluated visibility of origin, course, vessel lengths, image quality (IQ), and contrast between coronary lumen and myocardium. A subgroup was compared with cardiac catheter., Results: The total scan time was 6.3 +/- 3.2 minutes (mean +/- SD, at mean heart rate 76 +/- 15/min). The mean vessel length for right coronary artery (RCA) by observer 1 was 97 +/- 43 mm (observer 2: 94 +/- 37 mm), for left main and anterior descending artery (LM/LAD) 91 +/- 40 mm (observer 2: 90 +/- 40 mm), and for left circumflex artery (LCX) 64 +/- 28mm (observer 2: 66 +/- 28 mm). The mean vessel contrast was 0.34 +/- 0.05 (range: 0.23-0.45; maximum = 1, minimum = 0). On a 4-level score (1 = nondiagnostic, 4 = excellent), mean IQ scores ranged between 2.3-2.9 (+/-0.8-1.0). Both observers agreed on the presence/proximal course of RCA in 40/40, LM/LAD in 38/40, and LCX in 36/40 patients. There was complete agreement with invasive coronary angiography available in 12/40 patients (six anomalies)., Conclusion: Isotropic whole-heart 3D-MRI for cardiac morphology allows reliable discrimination between normal and abnormal coronary anatomy in children/adolescents with CHD.

Background: Cardiac magnetic resonance imaging (MRI) is an important diagnostic tool for congenital heart disease (CHD), as reflected by class 1 recommendations for the use of cardiac MRI by various consensus panels. However, little is known about the safety and clinical utility of cardiac MRI for these critically ill infants with CHD, whose further management cannot be directed by echocardiography. This study aimed to assess the safety, the potential hemodynamic side effects, and the clinical benefits of cardiac MRI for infants with complex CHD during their intensive care unit stay., Methods: Infants referred from the pediatric cardiac intensive care unit (PCICU) to the authors' cardiac MRI program in the past 2 years were retrospectively analyzed using the electronic chart system available at their institution. Data collected included age, diagnosis, inotropic support, urine output, diuretic medication, body temperature and lactate levels, length of MRI examination, adverse effects during and after the procedure, clinical implications of MRI, length of stay in the PCICU, and mean blood pressure and heart rate before, during, and after MRI., Results: Among 592 patients in the past 2 years, 20 (3.4%) were referred for MRI testing during their stay in the PCICU. The mean age of the infants was 4.8+/-3.2 months. Four of the patients were neonates, and eight were postoperative patients. Intracardiac malformations were present in 16 of the infants, vascular rings causing tracheal stenosis in 3 patients, and cardiomyopathy in 1 patient. The mean stay in the PCICU was 28+/-43 days. Eight of the infants were ventilated, with a mean fraction of inspired oxygen (FiO2) of 0.30+/-0.15. Four were receiving inotropic support. All the nonventilated children were intubated for the MRI and extubated in the MRI laboratory. The mean duration of the MRI (door-to-door time) was 110+/-27 min. All except one patient were hemodynamically stable, and no increase in catecholamine support was necessary during or after the scans. A 10-month-old girl receiving inotropic support needed a single dose of epinephrine due to a short episode of bradycardia after a breathhold for a contrast agent MRI angiography. Mean body core temperature at arrival to the PCICU was 36.8+/-0.7 degrees C. The mean serum lactate level after the MRI was 1.2+/-0.4 mmol/l. The mean blood pressure and heart rate before, during, and after MRI were unchanged. The mean diuresis on examination day was insignificantly lower (2.4%) than the day before with unchanged medication (5.09+/-1.58 vs 5.53+/-1.77 ml/kg/h). For 14 (70%) of the 20 patients, surgical or catheter interventional procedures were initiated based on novel MRI information., Conclusion: Cardiac MRI can be performed safely with low risk and limited hemodynamic changes for infants during their stay in the PCICU. Cardiac MRI provides key information for invasive management decisions in this subset of patients.

Careful preoperative planning is of outmost importance - in particular when considering complex corrective surgery on congenitally malformed hearts. As an aid to such decision-making we describe a system for virtual reconstruction of patient-specific morphology from 3D-capable imaging modalities such as MRI and CT. We introduce and illustrate the concept of virtual cardiotomy as a new tool to preoperatively evaluate the feasibility of different surgical strategies by investigating the anatomical spatial relations through any number of virtual incisions. We review the technical and clinical implementation of the various components of the system, namely 3D imaging, segmentation and reconstruction, visualization, and simulation of tissue elasticity. Finally we summarize the main findings from a recent evaluation study on 42 infants and children.

Background: Patient-specific preoperative planning in complex congenital heart disease may be greatly facilitated by virtual cardiotomy. Surgeons can perform an unlimited number of surgical incisions on a virtual 3-D reconstruction to evaluate the feasibility of different surgical strategies., Objective: To quantitatively evaluate the quality of the underlying imaging data and the accuracy of the corresponding segmentation, and to qualitatively evaluate the feasibility of virtual cardiotomy., Materials and Methods: A whole-heart MRI sequence was applied in 42 children with congenital heart disease (age 3 +/- 3 years, weight 13 +/- 9 kg, heart rate 96 +/- 21 bpm). Image quality was graded 1-4 (diagnostic image quality > or =2) by two independent blinded observers. In patients with diagnostic image quality the segmentation quality was also graded 1-4 (4 no discrepancies, 1 misleading error)., Results: The average image quality score was 2.7 - sufficient for virtual reconstruction in 35 of 38 patients (92%) older than 1 month. Segmentation time was 59 +/- 10 min (average quality score 3.5). Virtual cardiotomy was performed in 19 patients., Conclusion: Accurate virtual reconstructions of patient-specific cardiac anatomy can be produced in less than 1 h from 3-D MRI. The presented work thus introduces a new, clinically feasible noninvasive technique for improved preoperative planning in complex cases of congenital heart disease.

Background: Atypical left-to-right shunts at the level of the atrium in children such as sinus venosus atrial septal defects (ASDs) and partial anomalous pulmonary venous return (PAPVR) may be difficult to assess by transthoracic or transoesophageal echocardiography. Free-breathing cardiac MRI may be a powerful alternative., Objective: To assess the value of free-breathing cardiac MRI in the delineation of atypical ASDs in children., Materials and Methods: A total of 82 children (mean age 5.9 years, range 1.1-15.7 years) with suspected ASD and inconclusive transthoracic echocardiography underwent cardiac MRI under free-breathing, mostly sedated conditions. Phase-contrast MRI was used for defect visualization and shunt quantification, and multiphase inflow MR angiography for delineation of pulmonary/systemic venous connections., Results: Of the 82 patients, 34 (41%) were diagnosed with atypical shunt lesions at the level of the atrium and 48 (59%) with simple secundum ASDs. No false-negative or false-positive findings were reported by MRI compared to cardiac catheterization and intraoperative findings. Superior sinus venosus ASD with partial anomalous PAPVR was present in 10 of the 82 children (12.2%), whereas 2 (2.4%) had a large posterior-inferior defect, 5 (6.1%) had isolated PAPVR, and 17 (20.7%) had multiple ASDs and/or associated vascular anomalies. Q(p)/Q(s) by phase-contrast MRI agreed well with oximetry values (mean difference 3%, limits of agreement +/-21-25%; Bland/Altman analysis)., Conclusion: Free-breathing cardiac MRI under sedation allows reliable identification of atypical left-to-right shunt defects at the level of the atrium in children in whom transcatheter ASD closure is unsuitable, including delineation of pulmonary or systemic venous anomalies and shunt quantification.

Currently there are no biodegradable stents available for treatment of vascular obstructions in patients with congenital heart defects. This study was performed to evaluate the safety of a corrodible stent produced from pure iron in a peripheral stent design (6-12mm diameter) in a slotted tube design similar to a commercially available 316-L stent which served as control. Both stents were implanted into the descending aorta of 29 minipigs with an overstretch injury without technical problems. Two animals died after the implantation not related to the iron stent. The remaining 27 minipigs were followed for 1-360 days. Histomorphometry and quantitative angiography showed no difference with regard to the amount of neointimal proliferation between 316-L and iron stents. Histopathological examination of heart, lung, spleen, liver, kidney and para-aortic lymphatic nodes demonstrated no signs of iron overload or iron-related organ toxicity. Adjacent to the iron stent struts, there was no evidence for local toxicity due to corrosion products. We conclude that iron is a suitable metal for the production of a large-size degradable stent with no local or systemic toxicity. A faster degradation rate, however, is desirable and further studies have to focus on the modification of the composition and design of the stent to expedite the degradation process.

Purpose: Current standards in magnetic resonance imaging of congenital heart disease are based mostly on anisotropic protocols to image both morphology and function. Operator-dependent acquisition planning is typically needed to obtain the desired images. We propose to instead use operator-independent, three-dimensional, isotropic imaging protocols to acquire both morphology and function (cine and flow) of the entire heart in a few standardized acquisitions. Subsequently, due to the isotropic property of the data, any desired imaging plane can be "imaged" offline by interactive planar reformatting and used for qualitative and quantitative diagnostic evaluation., Materials and Methods: Morphological data was acquired in patients using 3D steady state free precession (SSFP) protocols, and functional data in volunteers using multislice 2D or 3D cine SSFP as well as 3D, three-component phase-contrast velocity mapping with EPI readouts. Tools to integrate morphological and functional offline image evaluation based on interactive planar reformatting, volume rendering, and corresponding quantification tools were implemented and discussed., Results: We successfully acquired and integrated morphology and flow and demonstrated potential clinical applications., Conclusion: User independent acquisitions of morphological and functional isotropic 3D datasets with real-time, interactive planar reformatting, volume rendering, and integration of morphology and function, have the potential to replace conventional, user dependent, anisotropic 2D imaging in patients with cardiac malformations.