Improving MR Image Quality in Patients with Metallic Implants.

The number of implanted devices such as orthopedic hardware and cardiac implantable devices continues to increase with an increase in the age of the patient population, as well as an increase in the number of indications for specific devices. Many patients with these devices have or will develop clinical conditions that are best depicted at MRI. However, implanted devices containing paramagnetic or ferromagnetic substances can cause significant artifact, which could limit the diagnostic capability of this modality. Performing imaging with MRI when an implant is present may be challenging, and there are numerous techniques the radiologist and technologist can use to help minimize artifacts related to implants. First, knowledge of the presence of an implant before patient arrival is critical to ensure safety of the patient when the device is subjected to a strong magnetic field. Once safety is ensured, the examination should be performed with the MRI system that is expected to provide the best image quality. The selection of the MRI system includes multiple considerations such as the effects of field strength and availability of specific sequences, which can reduce metal artifact. Appropriate patient positioning, attention to MRI parameters (including bandwidth, voxel size, and echo), and appropriate selection of sequences (those with less metal artifact and advanced metal reduction sequences) are critical to improve image quality. Patients with implants can be successfully imaged with MRI with appropriate planning and understanding of how to minimize artifacts. This improves image quality and the diagnostic confidence of the radiologist. ©RSNA, 2021.

Improving adherence to echocardiogram reporting guidelines in patients with repaired tetralogy of fallot: A quality improvement initiative.

BACKGROUND: In patients with repaired tetralogy of Fallot (TOF), key echocardiogram report elements have been identified, but poor adherence has been demonstrated, particularly for quantitative assessment. We report a quality improvement effort to improve adherence at our institution, with a focus on increasing quantitative assessment of right ventricular (RV) function. METHODS: Baseline compliance was established by a 3-month retrospective review of outpatient echocardiogram reports. Intervention 1 included presenting baseline data and reviewing the guidelines with echocardiogram laboratory staff (physicians and sonographers). Intervention 2, chosen to focus on quantitative assessment of RV function, involved recommending measurement of tricuspid annular plane systolic excursion (TAPSE) for all echocardiograms. Reporting rates were prospectively analyzed for 1 month after each intervention. To evaluate sonographer versus physician compliance, both study images (acquisition of TAPSE images) and reports were reviewed. RESULTS: At baseline, adherence was poor (median 65% of elements reported), with lower rates for measurements versus descriptive elements (median 40% vs 78%, p<.0001). Following intervention 1, total reported elements improved (median 71% vs 65%, p=0.02) due to increase in measurements (median 50% vs 40%, p=0.02). Reports of quantitative RV function did not significantly change after either intervention, but sonographer compliance improved after intervention 1 (33% vs 14%, p=0.03), with further improvement after intervention 2 (53% vs 14%, p=0.001). CONCLUSION: While education on lesion-specific guidelines may modestly improve adherence, standardization has a greater effect. However, interventions may have differential impact on sonographers versus attendings, and iterative interventions may be required to change practice patterns.

Differences in Pulmonary and Systemic Flow Measurements by Cardiac Magnetic Resonance vs Cardiac Catheterization and Relation to Collateral Flow in Single Ventricle Patients.

Both cardiac magnetic resonance (CMR) and cardiac catheterization (cath) may assess patients with single ventricle physiology prior to stage II or Fontan palliation. However, development of significant aortopulmonary collaterals may invalidate assumptions of the Fick method. We compared CMR and cath flow measurements and evaluated the relation to collateral flow. This single-center study included all pre-stage II and pre-Fontan patients between 2010 and 2017 with CMR and cath within 1 month. Pulmonary (Qp) and systemic flow (Qs) by cath were calculated by Fick method. CMR Qp was calculated by total pulmonary venous flow, and Qs by total vena caval flow. Collateral flow by CMR was the difference of pulmonary vein and pulmonary artery flow. In 26 studies (16 pre-stage II and 10 pre-Fontan) in 21 patients, collateral flow was higher in pre-Fontan patients (1.8 ± 0.6 vs 0.9 ± 0.8 L/min/m2, p = 0.01). Overall, CMR and cath had good agreement for Qs and Qp:Qs, with moderate correlation (r = 0.44, p = 0.02 for Qs, r = 0.48, p = 0.02 for Qp:Qs). In pre-Fontan but not in pre-stage II patients, CMR had higher Qp (mean difference - 1.71 L/min/m2) and Qp:Qs (mean difference - 0.36). The underestimation of cath Qp correlated with amount of collateral flow (r = - 0.47, p = 0.02). Neither cath nor CMR flow measurements correlated with outcomes in this small cohort. In conclusion, collaterals lead to systematically higher Qp and Qp:Qs measurements by CMR vs cath in single ventricle patients. Measurements may not be used interchangeably, with potential clinical significance in estimating pulmonary vascular resistance. Further study is necessary to evaluate possible relation to clinical outcomes.

Neo-aortic Root Dilatation, Aortic Stiffness, and Ventricular interactions in Long-Term Follow-Up After the Ross Procedure in Childhood.

Patients after the Ross procedure are at risk for right (RV) and left ventricular (LV) dysfunction due to neo-aortic and pulmonary dysfunction. While neo-aortic root dilatation has been related to LV dysfunction, the potential contributions of aortic stiffness and ventricular interactions have not been evaluated. Patients status post Ross procedure up to age 18 years with cardiac magnetic resonance (CMR) exam from 2007 to 2018 were retrospectively reviewed. Aortic pulse wave velocity (PWV) was calculated from phase contrast and angiogram images. RV and LV peak global longitudinal (GLS) and circumferential strain (GCS) were measured using tissue tracking software. Multivariable regression was performed for variables associated with parameters of LV function. In 58 patients (median age 20.5 years at CMR exam), male gender, longer time since Ross procedure, aortic root dilatation, and lower RV ejection fraction (EF) were associated with decreased LV EF. There was no association with LV late gadolinium enhancement or neo-aortic or conduit regurgitation. LV GCS and GLS also correlated with RV GCS, RV GLS and PWV. In multivariable analysis, the relation of RV and LV systolic function, but not aortic measurements, remained significant. In conclusion, in long-term follow-up after pediatric Ross procedure, RV function rather than aortic root size or aortic stiffness most closely relates to LV function. Ventricular interactions may impact decision-making on timing of conduit intervention, which could differ from established criteria in populations with only aortic or pulmonary valve disease. Further study is warranted to evaluate possible association with clinical outcome.

Phase-Contrast Magnetic Resonance Quantification of Aortic Regurgitation in Patients With Turbulent Aortic Flow.

OBJECTIVE: This study aimed to assess variability in measurements and accurately quantify aortic regurgitation in patients with coexisting turbulent aortic flow using phase-contrast magnetic resonance. METHODS: All patients (n = 21) underwent phase-contrast magnetic resonance at 2 or more sites: ascending aorta, sinuses of Valsalva, and left ventricular outflow tract. The net flow/minute (NF), forward flow/minute (FF), regurgitant flow/minute (RF), and regurgitant fraction (RF%) were compared with the sum of superior vena cava and descending aortic flow/minute, left ventricular cardiac output, difference between the 2, and percentage difference, respectively. RESULTS: The NF, FF, and RF were significantly different between each site. The combination of FF in the left ventricular outflow tract and NF from the superior vena cava + descending aorta provided the best reliability of RF and regurgitant fraction (intraclass correlation coefficients, 0.881 [95% confidence interval, 0.882-0.878] and 0.838 [95% confidence interval, 0.837-0.838]). CONCLUSION: Combining flow measurements from more than 1 site provides the most accurate quantification of aortic regurgitation in patients with turbulent aortic flow.

Differences in Right Ventricular Physiologic Response to Chronic Volume Load in Patients with Repaired Pulmonary Atresia Intact Ventricular Septum/Critical Pulmonary Stenosis Versus Tetralogy of Fallot.

BACKGROUND: Patients with pulmonary atresia with intact ventricular septum and critical pulmonary stenosis (PAIVS/CPS) have wide variation in right ventricle (RV) size, systolic function, and diastolic function at birth. Establishment of antegrade pulmonary blood flow creates the potential for RV dilation from chronic pulmonary insufficiency. Future surgical decisions are based on RV size and function, largely supported by longitudinal studies of patients with Tetralogy of Fallot (TOF). Given potential differences in RV physiology and lack of similar data in PAIVS/CPS, the objective of this study was to determine differences in RV size, systolic function, and diastolic function between patients with PAIVS/CPS versus TOF. METHODS: We retrospectively collected cardiovascular magnetic resonance (CMR) data in 27 patients with PAIVS/CPS (ages 13.3 ± 8.8 years) and 78 with TOF (11.4 ± 5.4 years). RV volumes, ejection fraction (EF), regurgitant fraction, end-diastolic forward flow across the pulmonary valve, and right atrial cross-sectional area were calculated. RESULTS: There was no difference between the groups in RV end-diastolic volume (RVEDVi), RVEF, or pulmonary regurgitation. RVEF tended to decrease in TOF when RVEDVi exceeded 164 ml/m2. In PAIVS/CPS, RVEDVi less frequently reached 164 ml/m2 and was not associated with RVEF. There was worse RV diastolic dysfunction in PAIVS/CPS, with 1.5 times larger right atrial area and two times higher pulmonary end-diastolic forward flow (p < 0.0001). CONCLUSIONS: Patients with PAIVS/CPS have similar RV size, systolic function, and pulmonary regurgitation as TOF. However, impaired RV diastolic function may limit extremes of RV dilatation and impact long-term management of PAIVS/CPS.

Differential Myocardial Mechanics in Volume and Pressure Loaded Right Ventricles Demonstrated by Cardiac Magnetic Resonance.

In patients with D-looped transposition of the great arteries (D-TGA) status post atrial switch operation, the systemic right ventricle (RV) shifts to predominantly circumferential (CS) rather than longitudinal strain (LS), which may represent adaptation or dysfunction. We aimed to evaluate myocardial mechanics in pressure loaded, volume-loaded, and normal RVs by cardiac magnetic resonance (CMR). Patients with D-TGA post atrial switch operation with CMR from 2008 to 2015 were matched 1:1 for age and RV ejection fraction (EF) with repaired tetralogy of Fallot (TOF) patients (volume-loaded RVs), and 1:1 for age with control patients. RV free wall LS and CS were measured using feature tracking software (TomTec, Unterscleissheim, Germany). A total of 32 D-TGA (median age 32 years, 56% male), 32 TOF, and 32 control patients were included. D-TGA patients had less dilatation than TOF patients (125 ± 35 ml/m2 vs. 149 ± 44 ml/m2, p = 0.02) and lower RVEF than controls (42.9 ± 7.7% vs. 56.3 ± 5.6%, p < 0.0001). RV LS was similar in D-TGA and TOF ( - 13.2 ± 4.5% vs. - 14.5 ± 5.9%, p = 0.32), both decreased compared to controls. However, CS in D-TGA was higher than controls ( - 14.1 ± 4.1% vs. - 11.4 ± 4.4%, p = 0.01), with a higher CS:LS ratio (1.2 ± 0.7 vs. 0.6 ± 0.3, p < 0.0001), while CS in TOF and controls did not differ. RVEF in D-TGA correlated closely with CS (r = - 0.85, p < 0.0001) but not LS (r = 0.10, p = 0.58). I n conclusion, CMR can differentiate strain patterns in pressure- and volume-loaded RVs, with decreased LS in both conditions, while systemic RVs compensate with supra-normal CS. CS may be a more clinically relevant measure of RV function in this population.

Primary cardiac tumors associated with genetic syndromes: a comprehensive review.

Various cardiac tumors occur in the setting of a genetic syndrome such as myxomas in Carney complex and rhabdomyomas in tuberous sclerosis. Tumor biology can be different in syndromic forms, and on imaging children sometimes demonstrate additional manifestations of the underlying syndrome. We discuss the imaging appearance of cardiac tumors occurring in the framework of a genetic syndrome, the findings that suggest an underlying syndrome, and the impact on management.

Predictors of missed appointments in patients referred for congenital or pediatric cardiac magnetic resonance.

BACKGROUND: Congenital cardiac magnetic resonance is a limited resource because of scanner and physician availability. Missed appointments decrease scheduling efficiency, have financial implications and represent missed care opportunities. OBJECTIVE: To characterize the rate of missed appointments and identify modifiable predictors. MATERIALS AND METHODS: This single-center retrospective study included all patients with outpatient congenital or pediatric cardiac MR appointments from Jan. 1, 2014, through Dec. 31, 2015. We identified missed appointments (no-shows or same-day cancellations) from the electronic medical record. We obtained demographic and clinical factors from the medical record and assessed socioeconomic factors by U.S. Census block data by patient ZIP code. Statistically significant variables (P<0.05) were included into a multivariable analysis. RESULTS: Of 795 outpatients (median age 18.5 years, interquartile range 13.4-27.1 years) referred for congenital cardiac MR, a total of 91 patients (11.4%) missed appointments; 28 (3.5%) missed multiple appointments. Reason for missed appointment could be identified in only 38 patients (42%), but of these, 28 (74%) were preventable or could have been identified prior to the appointment. In multivariable analysis, independent predictors of missed appointments were referral by a non-cardiologist (adjusted odds ratio [AOR] 5.8, P=0.0002), referral for research (AOR 3.6, P=0.01), having public insurance (AOR 2.1, P=0.004), and having scheduled cardiac MR from November to April (AOR 1.8, P=0.01). CONCLUSION: Demographic factors can identify patients at higher risk for missing appointments. These data may inform initiatives to limit missed appointments, such as targeted education of referring providers and patients. Further data are needed to evaluate the efficacy of potential interventions.

CT for Assessment of Thrombosis and Pulmonary Embolism in Multiple Stages of Single-Ventricle Palliation: Challenges and Suggested Protocols.

The total cavopulmonary connection (TCPC), or Fontan procedure, diverts systemic venous blood directly into the pulmonary arteries and is the palliative surgery of choice for patients with a wide variety of congenital heart diseases with single-ventricle physiologic characteristics. Pulmonary embolism and thrombosis are known complications and are among the major causes of morbidity and mortality in patients after TCPC. Magnetic resonance (MR) imaging is usually performed for postoperative evaluation of patients after single-ventricle repair; however, screening for thrombosis or embolism with MR imaging is not always feasible because of the emergent nature of the clinical presentation or because of artifacts from metallic devices or coils. Computed tomographic (CT) angiography is an effective method for diagnosing pulmonary embolism in children. However, because of altered hemodynamics after single-ventricle palliation, there are unique challenges in achieving optimal opacification of the pulmonary arteries and Fontan circuit that can result in nondiagnostic CT angiographic studies or erroneous image interpretation. Radiologists should be familiar with the multiple stages of single-ventricle palliation, understand the technique for performing pulmonary CT angiography at each stage, and recognize common pitfalls in obtaining and interpreting pulmonary CT angiographic images in patients who have undergone single-ventricle repair. Online supplemental material is available for this article. (©)RSNA, 2016.

Non-cardiovascular findings in clinical cardiovascular magnetic resonance imaging in children.

BACKGROUND: With increasing use of pediatric cardiovascular MRI, it is important for all imagers to become familiar with the spectrum of non-cardiovascular imaging findings that can be encountered. OBJECTIVE: This study aims to ascertain the prevalence and nature of these findings in pediatric cardiovascular MRIs performed at our institution. MATERIALS AND METHODS: We retrospectively evaluated reports of all cardiovascular MRI studies performed at our institute from January 2008 to October 2012 in patients younger than18 years. Most studies (98%) were jointly interpreted by a pediatric cardiologist and a radiologist. We reviewed the electronic medical records of all cases with non-cardiovascular findings, defined as any imaging finding outside the cardiovascular system. Non-cardiovascular findings were classified into significant and non-significant, based on whether they were known at the time of imaging or they required additional workup or a change in management. RESULTS: In 849 consecutive studies (mean age 9.7 ± 6.3 years), 145 non-cardiovascular findings were found in 140 studies (16.5% of total studies). Overall, 51.0% (74/145) of non-cardiovascular findings were in the abdomen, 30.3% (44/145) were in the chest, and 18.6% (27/145) were in the spine. A total of 19 significant non-cardiovascular findings were observed in 19 studies in individual patients (2.2% of total studies, 47% male, mean age 5.9 ± 6.7 years). Significant non-cardiovascular findings included hepatic adenoma, arterially enhancing focal liver lesions, asplenia, solitary kidney, pelvicaliectasis, renal cystic diseases, gastric distention, adrenal hemorrhage, lung hypoplasia, air space disease, bronchial narrowing, pneumomediastinum and retained surgical sponge. CONCLUSION: Non-cardiovascular findings were seen in 16.5% of cardiovascular MRI studies in children, of which 2.2% were clinically significant findings. Prevalence and nature of these non-cardiovascular findings are different from those reported in adults. Attention to these findings is important during interpretation.

Parental Preferences Regarding Outpatient Management of Children with Congenital Heart Disease.

The objective of this study was to identify patterns of health care usage among children with congenital heart disease (CHD) and determine predictors for contacting cardiologists for routine care. Parents of children with CHD completed surveys, indicating which provider they would contact first for 12 concerns. Predictors for preference for cardiologist evaluation were identified by multivariable logistic regression. Surveys were completed by 307 of 925 (33.2%) parents. Median patient age was 9.4 years [interquartile range (IQR) 5.1-14.4 years] with a median of 1 cardiac surgery (IQR 1-3). Most parents agreed primary care physicians (PCPs) could identify problems related to CHD (70.0%) and when to refer to cardiologists (89.6%). More felt PCPs best understood their values (63.2 vs. 29.6%, P < 0.001) and were more accessible (63.5 vs. 33.6%, P < 0.001) than cardiologists. Parents preferred first evaluation by PCPs for 9 of 12 concerns. Preference for cardiology evaluation was independently associated with the number of cardiac catheterizations [adjusted odds ratio (AOR) for ≥2 catheterizations 2.4, 95% confidence interval (CI) 1.1-4.9], belief the cardiologist better knew the child's medical history (AOR 2.4, 95% CI 1.3-4.6), and provider accessibility (AOR 3.6, 95% CI 1.8-7.4). Parents of CHD patients reported close alignment with PCPs and would contact PCPs first for most routine care. However, some populations continue to contact cardiologists for routine care. Further study is needed to clarify best practices for clinician and parent education.

Predictors of Change in Functional Health Status in Adults with Repaired Tetralogy of Fallot.

Left ventricular (LV) ejection fraction (EF) and right ventricular (RV) ejection fraction by cardiovascular magnetic resonance (CMR) are associated with functional health status in patients with repaired tetralogy of Fallot (TOF) in cross-sectional studies, but few longitudinal data are available. This study aimed to determine predictors of subsequent decrease in functional health status in midterm follow-up. Patients with repaired TOF who had previously completed CMR and assessment with the Short Form 36 version 2 (SF-36) were recruited for repeat CMR, SF-36, and exercise test, if they had not had interval pulmonary valve replacement (PVR). Patients from the same cohort who had undergone PVR were recruited for repeat SF-36. A total of 19 patients (median 33.5 years old, interquartile range [IQR] 26-42 years, 53 % male) had not undergone PVR and were enrolled at a median of 5.0 years (IQR 4.8-5.3) since prior CMR and SF-36. LVEF and RVEF did not change from baseline, while RV end-diastolic volume increased (138 ± 34 vs. 126 ± 31 ml/m(2), p = 0.02). In the overall cohort, SF-36 scores remained stable. However, higher baseline RV end-systolic volume and pulmonary regurgitant fraction correlated with subsequent decreases in SF-36 scores. In 9 patients post-PVR (median 35.9 years old, IQR 24-43), physical functioning increased compared to those without PVR (change in z-score +0.59 ± 0.59 vs. -0.26 ± 0.72, p = 0.005). In adults with repaired TOF who do not undergo PVR, LVEF, RVEF, and functional health status remain stable in midterm follow-up. However, baseline RV end-systolic volume correlates with subsequent change in functional health status, underscoring its importance in prognostication and timing of intervention in this population.

Factors associated with the internal jugular venous approach for Melody™ Transcatheter Pulmonary Valve implantation.

BACKGROUND: Transcatheter pulmonary valve implantation is usually performed from a femoral venous - transfemoral - approach, but this may not be the optimal vascular access option in some patients. This study aimed to determine which group of patients might benefit from an internal jugular - transjugular - approach for transcatheter pulmonary valve implantation. METHODS: This multicentre retrospective study included all patients who underwent attempted transcatheter pulmonary valve placement in the right ventricular outflow tract between April 2010 and June 2012 at two large congenital heart centres. Patients were divided into two groups based on venous access site - transfemoral or transjugular. Patient characteristics, procedural outcomes, and complications were compared between groups. RESULTS: Of 81 patients meeting the inclusion criteria (median age 16.4 years), the transjugular approach was used in 14 patients (17%). The transjugular group was younger (median age 11.9 versus 17.3 years), had lower body surface area (mean 1.33 versus 1.61 m2), more often had moderate or greater tricuspid regurgitation (29% versus 7%), and had a higher ratio of right ventricle-to-systemic systolic pressure (mean 82.4 versus 64.7). Patients requiring a transjugular approach after an unsuccessful transfemoral approach had longer fluoroscopic times and procedure duration. CONCLUSIONS: The transjugular approach for transcatheter pulmonary valve implantation is used infrequently but is more often used in younger and smaller patients. Technical limitations from a transfemoral approach may be anticipated if there is moderate or greater tricuspid regurgitation or higher right ventricular pressures. In these patients, a transjugular approach should be considered early.

Use of a 1.0 Tesla open scanner for evaluation of pediatric and congenital heart disease: a retrospective cohort study.

BACKGROUND: Open cardiovascular magnetic resonance (CMR) scanners offer the potential for imaging patients with claustrophobia or large body size, but at a lower 1.0 Tesla magnetic field. This study aimed to evaluate the efficacy of open CMR for evaluation of pediatric and congenital heart disease. METHODS: This retrospective, cross-sectional study included all patients ≤18 years old or with congenital heart disease who underwent CMR on an open 1.0 Tesla scanner at two centers from 2012-2014. Indications for CMR and clinical questions were extracted from the medical record. Studies were qualitatively graded for image quality and diagnostic utility. In a subset of 25 patients, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were compared to size- and diagnosis-matched patients with CMR on a 1.5 Tesla scanner. RESULTS: A total of 65 patients (median 17.3 years old, 60% male) were included. Congenital heart disease was present in 32 (50%), with tetralogy of Fallot and bicuspid aortic valve the most common diagnoses. Open CMR was used due to scheduling/equipment issues in 51 (80%), claustrophobia in 7 (11%), and patient size in 3 (5%); 4 patients with claustrophobia had failed CMR on a different scanner, but completed the study on open CMR without sedation. All patients had good or excellent image quality on black blood, phase contrast, magnetic resonance angiography, and late gadolinium enhancement imaging. There was below average image quality in 3/63 (5%) patients with cine images, and 4/15 (27%) patients with coronary artery imaging. SNR and CNR were decreased in cine and magnetic resonance angiography images compared to 1.5 Tesla. The clinical question was answered adequately in all but 2 patients; 1 patient with a Fontan had artifact from an embolization coil limiting RV volume analysis, and in 1 patient the right coronary artery origin was not well seen. CONCLUSIONS: Open 1.0 Tesla scanners can effectively evaluate pediatric and congenital heart disease, including patients with claustrophobia and larger body size. Despite minor artifacts and differences in SNR and CNR, the majority of clinical questions can be answered adequately, with some limitations with coronary artery imaging. Further evaluation is necessary to optimize protocols and image quality.

Cardiovascular magnetic resonance techniques and findings in children with myocarditis: a multicenter retrospective study.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is increasingly used to diagnose myocarditis in adults but its use in children is not well-established. We sought to describe the presentation, CMR protocol and findings, and outcomes in a multicenter cohort of children with myocarditis. METHODS: Thirteen hospitals retrospectively identified patients meeting the following inclusion criteria: 1) diagnosis of myocarditis by the managing physicians, 2) age <21 years, 3) CMR examination within 30 days of presentation, and 4) no congenital heart disease. Clinical data and test results, including CMR findings, were abstracted from the medical record. RESULTS: For the 143 patients meeting inclusion criteria, the median age was 16.0 years (range, 0.1-20.3) and 139 (97 %) were hospitalized at the time of CMR. The median time from presentation to CMR was 2 days (0-28). The median left ventricular ejection fraction at CMR was 56 % (10-74), with 29 (20 %) below 45 %. The median right ventricular ejection fraction was 54 % (15-72), with 11 (8 %) below 40 %. There was significant variability among centers in the types of tissue characterization techniques employed (p < 0.001). Overall, late gadolinium enhancement (LGE) was used in 100 % of studies, followed by T2-weighted imaging (T2W) in 69 %, first-pass contrast perfusion (FPP) in 48 %, and early gadolinium enhancement (EGE) in 28 %. Abnormalities were most common with LGE (81 %), followed by T2W (74 %), EGE (55 %), and FPP (8 %). The CMR study was interpreted as positive for myocarditis in 117 patients (82 %), negative in 18 (13 %), and equivocal in 7 (5 %), yielding a sensitivity of 82 %. At a median follow-up of 7.1 months (0-87), all patients were alive and 5 had undergone cardiac transplantation. CMR parameters at presentation associated with persistent left ventricular dysfunction were larger left ventricular end-diastolic volume and lower left and right ventricular ejection fraction but not abnormal LGE. CONCLUSIONS: Despite significant practice variation in imaging protocol among centers, CMR had a high sensitivity for the diagnosis of myocarditis in pediatric patients. Abnormalities were most often seen with LGE followed by T2W, EGE, and FPP. These findings should be useful in designing future prospective studies.

Levoatriocardinal Vein and Mimics: Spectrum of Imaging Findings.

OBJECTIVE: This article focuses on the embryology, hemodynamics, and CT and MRI features of levoatriocardinal vein. Levoatriocardinal vein, a form of pulmonary systemic connection, is most commonly seen in left heart obstructive lesions, providing an alternative egress for pulmonary venous blood. CONCLUSION: Levoatriocardinal vein can be differentiated from other more common anomalies, such as anomalous pulmonary venous return, persistent left superior vena cava, and dilated left superior intercostal vein, by its distinctive imaging features.

Left atrial deformation predicts pulmonary capillary wedge pressure in pediatric heart transplant recipients.

BACKGROUND: Pulmonary capillary wedge pressure (PCWP) is an important indicator in pediatric heart transplant patients, but commonly used noninvasive surrogates, such as ratio of early diastolic mitral inflow velocity to annular velocity (E/E'), have limitations in this population. This study aimed to evaluate the relation of left atrial (LA) peak systolic strain and distensibility with PCWP in pediatric heart transplant recipients. METHODS: Consecutive pediatric heart transplant patients were enrolled at time of cardiac catheterization, with echocardiogram immediately afterward. E/E' ratio at the lateral and medial mitral annulus, peak LA systolic longitudinal strain by speckle tracking, and LA distensibility were measured from echocardiograms and compared to invasively measured PCWP. RESULTS: In 38 patients (11.1 ± 5.8 years old), PCWP correlated with peak LA systolic strain (r = -0.44, P = 0.01) and LA distensibility (r= -0.43, P = 0.02), but not with E/E'. On receiver operating characteristics analysis, LA strain had a higher area under the curve than LA distensibility (0.846 vs. 0.606). LA strain <18.9% had sensitivity 62% and specificity 95%, with likelihood ratio 12.3 for PCWP ≥12. However, LA strain had lower intra-observer and inter-observer reproducibility than distensibility (intra-class correlation coefficients 0.89 and 0.75 vs. 0.93 and 0.90). CONCLUSIONS: Peak LA systolic strain and LA distensibility may be more useful surrogates of left ventricular filling pressure than E/E' in the pediatric heart transplant population, with greater reproducibility of LA distensibility. Longitudinal studies are needed to evaluate which parameters track changes in PCWP and clinical outcome.

MRI of pediatric cardiac masses.

OBJECTIVE: The purpose of this article is to describe the characteristic cardiac MRI features of primary and secondary cardiac tumors, including differentiation from masslike lesions, such as thrombus or focal myocardial hypertrophy. CONCLUSION: The frequency and type of cardiac tumors in children differ from those in adults. Although transthoracic echocardiography is the initial imaging technique of choice for evaluation of cardiac tumors, cardiac MRI is an important complementary modality for characterization of the mass and effect on cardiac function.

Strain measurement by cardiovascular magnetic resonance in pediatric cancer survivors: validation of feature tracking against harmonic phase imaging.

BACKGROUND: Left ventricular strain may be a more sensitive marker of left ventricular dysfunction than ejection fraction in pediatric cancer survivors after anthracycline therapy, but there is limited validation of strain measurement by feature tracking on cardiovascular magnetic resonance (MR) images. OBJECTIVE: To compare left ventricular circumferential and radial strain by feature tracking vs. harmonic phase imaging analysis (HARP) in pediatric cancer survivors. MATERIALS AND METHODS: Twenty-six patients (20.2 ± 5.6 years old) underwent cardiovascular MR at least 5 years after completing anthracycline therapy. Circumferential and radial strain were measured at the base, midventricle and apex from short-axis myocardial tagged images by HARP, and from steady-state free precession images by feature tracking. RESULTS: Left ventricular ejection fraction more closely correlated with global circumferential strain by feature tracking (r = -0.63, P = 0.0005) than by HARP (r = -0.39, P = 0.05). Midventricular circumferential strain did not significantly differ by feature tracking or HARP (-20.8 ± 3.4 vs. -19.5 ± 2.5, P = 0.07), with acceptable limits of agreement. Midventricular circumferential strain by feature tracking strongly correlated with global circumferential strain by feature tracking (r = 0.87, P < 0.0001). Radial strain by feature tracking had poor agreement with HARP, particularly at higher values of radial strain. Intraobserver and interobserver reproducibility was excellent for feature tracking circumferential strain, but reproducibility was poor for feature tracking radial strain. CONCLUSION: Midventricular circumferential strain by feature tracking is a reliable and reproducible measure of myocardial deformation in patients status post anthracycline therapy, while radial strain measurements are unreliable. Further studies are necessary to evaluate potential relation to long-term outcomes.