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We aimed to determine quantitative sacroiliac (SI) joint magnetic resonance imaging (MRI) cutoffs for active and structural lesions that will be incorporated as imaging domains in classification criteria of axial disease in juvenile spondyloarthritis (SpA). MRI scans from an international cross‐section of juvenile SpA patients were reviewed by 6 musculoskeletal imaging experts blinded to clinical details. Raters globally assessed the presence/absence of lesions typical of axial SpA and performed SI joint quadrant‐ or joint‐based scoring. Sensitivity and specificity of lesion cutoffs were calculated using a rater majority (≥4 of 6 raters) on a global assessment of the presence/absence of active or structural lesions typical of axial SpA with high confidence as the reference standard. Cutoffs were validated in an independent cohort. Imaging from 243 subjects, 61% male, median age 14.9 years, had sequences available for detailed MRI scoring. Optimal cutoffs for defining lesions typical of axial disease in juvenile SpA were: 1) inflammatory lesion: bone marrow edema in ≥3 SI joint quadrants across all SI joint MRI slices (sensitivity 98.6%, specificity 96.5%); 2) structural lesions: erosion in ≥3 quadrants or sclerosis or fat lesion in ≥2 SI joint quadrants or backfill or ankylosis in ≥2 joint halves across all SI joint MRI slices (sensitivity 98.6%, specificity 95.5%). Sensitivity and specificity of the optimal cutoffs in the validation cohort were excellent. We propose data‐driven cutoffs for active inflammatory and structural lesions on MRI typical of axial disease in juvenile SpA that have high specificity and sensitivity using central imaging global assessment as the reference standard and excellent reliability.

A diagnostic strategy for assessment of childhood interstitial lung disease is necessary for understanding and categorizing these conditions and facilitating improved patient care.

Central conducting lymphatic anomaly (CCLA) is a heterogenous disorder caused by disruption of central lymphatic flow that may result in dilation or leakage of central lymphatic channels. There is also a paucity of known genetic diagnoses associated with CCLA. We hypothesized that specific genetic syndromes would have distinct lymphatic patterns and this would allow us to more precisely define CCLA. As a first step toward “precision lymphology”, we defined the genetic conditions associated with CCLA by performing a retrospective cohort study. Individuals receiving care through the Jill and Mark Fishman Center for Lymphatic Disorders at the Children’s Hospital of Philadelphia between 2016 and 2019 were included if they had a lymphangiogram and clinical genetic testing performed and consented to a clinical registry. In our cohort of 115 participants, 26% received a molecular diagnosis from standard genetic evaluation. The most common genetic etiologies were germline and mosaic RASopathies, chromosomal abnormalities including Trisomy 21 and 22q11.2 deletion syndrome, and PIEZO1-related lymphatic dysplasia. Next, we analyzed the dynamic contrast magnetic resonance lymphangiograms and found that individuals with germline and mosaic RASopathies, mosaic KRASopathies, PIEZO1-related lymphatic dysplasia, and Trisomy 21 had distinct central lymphatic flow phenotypes. Our research expands the genetic conditions associated with CCLA and genotype-lymphatic phenotype correlations. Future descriptions of CCLA should include both genotype (if known) and phenotype to provide more information about disease (gene-CCLA). This should be considered for updated classifications of CCLA by the International Society of Vascular Anomalies.

Imaging plays a central role in improving our understanding of the lymphatic system and in the diagnosis and treatment of lymphatic abnormalities, and radiologists should understand normal and variant lymphatic anatomy, disorders of the lymphatic system, and evolving diagnostic techniques and treatment options.

Protein-losing enteropathy (PLE) is a disorder of intestinal lymphatic flow resulting in leakage of protein-rich lymph into the gut lumen. Our primary aim was to report the imaging findings of dynamic contrast magnetic resonance lymphangiography (DCMRL) in patients with PLE. Our secondary objective was to use these imaging findings to characterize lymphatic phenotypes. Single-center retrospective cohort study of patients with PLE unrelated to single-ventricle circulation who underwent DCMRL. We report imaging findings of intranodal (IN), intrahepatic (IH), and intramesenteric (IM) access points for DCMRL. Nineteen patients 0.3–58 years of age (median 1.2 years) underwent 29 DCMRL studies. Primary intestinal lymphangiectasia (PIL) was the most common referring diagnosis (42%). Other etiologies included constrictive pericarditis, thoracic insufficiency syndrome, and genetic disorders. IN-DCMRL demonstrated a normal central lymphatic system in all patients with an intact thoracic duct and localized duodenal leak in one patient (1/19, 5%). IH-DCMRL detected a duodenal leak in 12 of 17 (71%), and IM-DCMRL detected duodenal leak in 5 of 6 (83%). Independent of etiology, lymphatic leak was only visualized in the duodenum. In patients with PLE, imaging via DCMRL reveals that leak is localized to the duodenum regardless of etiology. Comprehensive imaging evaluation with three access points can provide detailed information about the site of duodenal leak.

Most pediatric masses in the chest are located in the mediastinum. These masses are often initially detected incidentally on chest radiographs in asymptomatic children, although some patients may present with respiratory symptoms. At chest radiography, the mediastinum has been anatomically divided into anterior, middle, and posterior compartments. However, with the International Thymic Malignancy Interest Group classification scheme, which is based on cross-sectional imaging findings, the mediastinum is divided into prevascular, visceral, and paravertebral compartments. In the prevascular compartment, tumors of thymic origin, lymphomas, germ cell tumors, and vascular tumors are encountered. In the visceral compartment, lymphadenopathy and masses related to the foregut are seen. In the paravertebral compartment, neurogenic tumors are most common. Using the anatomic location in combination with knowledge of the imaging and pathologic features of pediatric mediastinal masses aids in accurate diagnosis of these masses to guide treatment and management decisions.An invited commentary by Lee and Winantis available online.©RSNA, 2021

Cardiac neoplasms are a diagnostic challenge on many levels. They are rare, their clinical presentation may mimic other much more common cardiac diseases, and they are at an uncommon intersection of oncologic and cardiac imaging. The pathology of primary cardiac neoplasms explains their varied imaging features, for example, calcification in primary cardiac osteosarcomas and T2 hyperintensity in myxomas. Integrating the imaging and pathologic features of cardiac tumors furthers our understanding of the spectrum of appearances of these neoplasms and improves the clinical imager’s ability to confidently make a diagnosis.

Abstract: Neonatal chylothorax (NCTx) and central lymphatic flow disorder (CLFD) are historically challenging neonatal disorders with high morbidity and mortality. Methods: We conducted a retrospective study of 35 neonates with pulmonary lymphatic abnormalities at our institution who underwent lymphatic evaluation between December 2015 and September 2018. Patients with only pulmonary lymphatic perfusion syndrome were classified as NCTx and those with multiple flow abnormalities were classified as CLFD. Demographics, clinical characteristics, and outcomes were compared using t-tests/Wilcoxon rank sum tests and Fisher’s exact tests. Results: All 35 patients had intranodal MR lymphangiography and 14 (40%) also had conventional fluoroscopic lymphangiography. Fifteen (42.8%) patients were diagnosed with NCTx and 20 (57.1%) were diagnosed with CLFD. Thirty-four (97.1%) patients had pleural effusions. None of the NCTx group had ascites, anasarca, or dermal backflow compared to 17 (85%) (p< 0.001), 8 (42.1%) (p: 0.004), and 20 (100%) (p< 0.001) of the CLFD group, respectively. In the NCTx group, 11 (73.3%) had ethiodized oil embolization and 4 (26.7%) received conservative therapy. Ten (50%) of the CLFD patients had an intervention; of those, two (10%) had ethiodized oil-only embolization. Eight had non-ethiodized oil embolizations (two (25%) had embolization with glue, three (37.5%) underwent surgical lymphovenous anastomosis, two (25%) underwent thoracic duct (TD) externalization, and one (12.5%) had a non-TD lymphatic channel drain placed). Complete resolution of pleural effusions was achieved in all 15 NCTx patients, whereas 9 (45%) of 20 CLFD patients had resolution of chylothorax (p: 0.001). Conclusions: Establishing a diagnosis of NCTx or CLFD is paramount in selecting treatment options and providing prognostic information. Development of lymphatic interventions represents a paradigm shift in our understanding of neonatal lymphatic flow disorders and may be associated with improved survival.

Patients with single ventricle physiology and greater extension and distribution of lymphatic channels in the chest and neck on T2-weighted MRI had worse outcomes after planned Fontan surgery.

Recent advances in understanding lymphatic disorders have significantly improved noninvasive imaging of the lymphatic circulation, especially in pediatric patients. The ability to obtain high-quality MR imaging using 3-dimensional reconstruction has transformed the display of the lymph vessels and substantially enhanced the ability to diagnose various pediatric lymphatic disorders. Real-time dynamic imaging adds functional information to the assessment. MR imaging is increasingly used, not only to assess but also as a follow-up after lymphatic disorder treatment. This article discusses up-to-date imaging techniques and clinical applications of dynamic magnetic resonance lymphangiography for assessing central conducting lymphatic anomalies.

Although primary lung tumors in children are rare, key radiologic and pathologic features of these tumors play a complementary role and allow discrimination of these tumors to guide clinical management.

Objective.There is a critical need for measures to evaluate structural progression in the pediatric sacroiliac joint (SIJ). We aimed to evaluate the construct validity and reliability of the Spondyloarthritis Research Consortium of Canada SIJ Structural Score (SSS) in children with suspected or confirmed juvenile spondyloarthritis.Methods.The SSS assesses structural lesions of the SIJ on magnetic resonance imaging (MRI) through the cartilaginous part of the joint. We conducted 3 sequential reading exercises with 6 readers (1 adult and 3 pediatric radiologists, 1 adult and 1 pediatric rheumatologist). Each exercise was preceded by a calibration module. Interobserver reliability was assessed using intraclass correlation coefficients (ICC). Prespecified acceptable reliability thresholds were ICC > 0.5 for erosion, backfill, and sclerosis, and ICC > 0.7 for ankylosis and fat metaplasia.Results.The SSS had face validity and was feasible to score in pediatric cases for all 3 reading exercises. Of the cases used in the 3 exercises, 58% were male and the median age was 14 years (range 6.8–18.7 yrs). After calibration, median ICC across all readers for each SSS component were the following: erosion 0.67 (interquartile range 0.54–0.80), backfill 0.33 (0.19–0.52), fat metaplasia 0.74 (0.62–0.85), sclerosis 0.63 (0.48–0.77), and ankylosis 0.44 (0.28–0.62). Prespecified reliability thresholds were achieved in the third exercise for erosion, sclerosis, and fat metaplasia but not for backfill or ankylosis.Conclusion.The SSS was feasible to score and had acceptable reliability for pediatric SIJ MRI evaluation. The ICC improved with additional calibration and reading exercises, even for readers with limited experience.

Primary cardiac and pericardial tumors are diagnostic challenges that may mimic more common cardiovascular diseases, but advanced imaging techniques and knowledge of their pathologic basis can help differentiate benign from malignant tumors.

The authors review the composition, physiologic properties, and safety profile of US contrast agents; describe their technique for performing contrast-enhanced US; and highlight the advantages of using this modality to assess common focal liver lesions in children.

To evaluate the prevalence of sacroiliitis at diagnosis of juvenile spondyloarthritis (SpA) and the accuracy of physical examination and back pain to detect sacroiliitis, using imaging as the reference standard. We performed a prospective cross‐sectional study of 40 children with newly diagnosed juvenile SpA and 14 healthy controls. Subjects were assessed using physical examination, anteroposterior pelvic radiograph, and pelvic magnetic resonance imaging (MRI). Differences in clinical features between those children with and without sacroiliitis were assessed by Fisher's exact test for categorical variables and Wilcoxon's rank sum test for continuous variables. Accuracy of physical examination and back pain for detection of sacroiliitis was determined using MRI as the reference standard. Predicted probability of sacroiliitis was determined using exact multivariate logistic regression. Eight children (20%) with juvenile SpA had active sacroiliitis. Of those subjects with active changes on MRI, 7 of 8 (88%) also had evidence of erosions or sclerosis. Five children (13%) with juvenile SpA and 1 control (7%) had nonperiarticular bone marrow edema. Of the subjects with active sacroiliitis, only 3 (38%) reported a history of back pain or tenderness on palpation of the sacroiliac joints. The positive and negative predictive values of clinical examination features and back pain for detection of sacroiliitis were low. The estimated probability of having sacroiliitis was 0.84 (95% confidence interval 0.40–1.00) in HLA–B27–positive patients with an elevated C‐reactive protein (CRP) level. Active sacroiliitis by MRI is common at diagnosis in juvenile SpA and is frequently asymptomatic. Children who are HLA–B27–positive and have elevated CRP levels have the highest probability of sacroiliitis.

Cardiovascular disease in children comprises a diverse collection of diseases involving multiple organ systems. Abnormality in children is predominately congenital but also may be acquired. Although noninvasive vascular imaging modalities such as magnetic resonance angiography and ultrasound lack ionizing radiation, with improving technology and an increased focus on radiation dose reduction, computed tomographic angiography (CTA) continues to have a role in evaluating cardiovascular disease in pediatric patients. This review focuses on specific considerations of CTA that the radiologist or ordering provider should consider when imaging the pediatric cardiovascular system.

Introduction:Cardiac magnetic resonance (CMR) provides rich data on myocardial function, including indices such as strain, as well as tissue characterization. There is no published data on these values within 2 weeks of the diagnosis of myocarditis. We sought to describe these findings in children with acute myocarditis who underwent CMR early after presentation and determine relationships between these values.Methods:We retrospectively reviewed the clinical and imaging data of patients <21 years clinically diagnosed with acute myocarditis and underwent CMR within 14 days of presentation. Those who suffered cardiac arrest or with autoimmune disease, known cardiomyopathy or congenital heart disease were excluded. Strain was measured using CMR feature tracking. Spearman’s correlation was utilized. Significance was P <0.05.Results:85 patients underwent CMR at a median of 2 days following presentation (IQR 2 - 4) with median age 16.3 years (IQR 14.3, 17.5). Tissue characteristics, ventricular function and strain are listed in Table 1. 77 studies (90.6%) met Lake Louise criteria for myocarditis and 66 (77.7%) showed late gadolinium enhancement. Global circumferential (GCS) and longitudinal strain correlated with T2 values, biventricular ejection fractions, and peak brain natriuretic peptide (BNP); GCS also correlated with T1 values (Table 1, Figure 1).Conclusions:We present the first data on early strain and tissue characterization for myocarditis. Both global longitudinal and circumferential strain correlated with tissue characteristics and serum measures of acute injury. Strain imaging may be a sensitive marker of myocardial injury in patients with myocarditis.

The differential diagnoses of pediatric abdominal and pelvic tumors arising in solid organs are generally well known, but the pathologic features of tumors originating outside these organs—from the peritoneum, omentum, and mesentery—are much less familiar. The pathologic spectrum of solid masses arising in the peritoneal cavity is addressed with emphasis on radiologic-pathologic correlation.

Bowel wall thickening on computed tomography (CT) scans in children may raise concern for inflammatory bowel disease (IBD). The significance of this radiological finding is unclear. Our purpose was to evaluate the clinical outcomes with regard to IBD in children with no known underlying disease, presenting with abdominal pain and thickened bowel wall on CT scan.

Bowel wall thickening on computed tomography (CT) scans in children may raise concern for inflammatory bowel disease (IBD). The significance of this radiological finding is unclear. Our purpose was to evaluate the clinical outcomes with regard to IBD in children with no known underlying disease, presenting with abdominal pain and thickened bowel wall on CT scan. A retrospective analysis of pediatric patients with abdominal pain and CT findings of thickened bowel wall was performed between 2006 and 2010. Endoscopic findings, clinical variables, and follow-up assessments were evaluated. Fifty-six patients presenting with abdominal pain and thickened bowel wall findings on CT scan were identified. Overall, 30 (54%) had terminal ileum wall thickening, 17 (30%) had isolated colonic wall thickening, and 9 (16%) had other small bowel wall thickening. Of the 56 patients, 21 (38%) underwent endoscopy, of which 14 (67%) had positive findings—11 (79%) had histologic evidence of chronic colitis, and 5 (36%) had duodenitis/ileitis. Ultimately, 11/56 (20%) were diagnosed as having IBD, 8/56 (14%) with functional abdominal pain/constipation, 9/56 (16%) appendicitis, 10/56 (18%) infectious gastroenteritis, and 18/56 (32%) with miscellaneous diagnoses. Median levels of erythrocyte sedimentation rate, C-reactive protein, albumin, and platelet count were significantly abnormal in the IBD group compared to the non-IBD group. Additional follow-up of those who did not undergo endoscopic evaluation revealed no new diagnoses of IBD. The presence of thickened bowel wall on CT scans is a nonspecific finding in children. Laboratory evaluation may help distinguish which patients require additional evaluation and endoscopy.

Introduction:Patients with malaligned common atrioventricular (AV) canal (CAVC) are difficult to manage when one ventricle is borderline hypoplastic. The decision between the single ventricle pathway or attempting a biventricular repair depends upon pre-operative parameters which have previously been studied only by echocardiography. The purpose of this study was to determine the utility of cardiac magnetic resonance (CMR) in predicting success of a biventricular repair in CAVC.Methods:We performed a single center, retrospective cohort study of children with varying degrees of CAVC malalignment who underwent CMR prior to definitive repair (7/1/10 to 2/28/21). The primary outcome was successful biventricular repair. CMR measurements were performed by the investigators. To account for both dominant right ventricles (RV) and left ventricles (LV), ratios of ventricular and AV valve size were normalized as differences from their expected values. Associations were tested using univariable logistic regression. Multivariable regression models using combinations of two variables with p-values less than 0.2 were tested.Results:We included 28 patients (median age at CMR: 5.2 months, 43% male). Clinical and CMR variables are shown in Table 1. The optimal multivariable predictive model included the normalized LV end diastolic volume (EDV) to total ventricular EDV ratio and the LV-RV angle in diastole. Area under the receiver operator characteristic curve was 0.83 (p = 0.041). An LV EDV to total EDV ratio between 0.30 and 0.66 had a sensitivity of 92% and specificity of 63% for predicting successful biventricular repair. Including an LV-RV angle in diastole of less than 72 degrees resulted in a sensitivity of 83% and specificity of 81%.Conclusions:Multiple CMR measures were associated with surgical outcomes. CMR measures such as LV EDV to total ventricular EDV ratio and LV-RV angle in diastole can accurately predict successful biventricular canal repair.

Introduction:Single ventricle patients develop aortopulmonary collaterals (APC) whose flow (APCF) has been shown, in a cross-sectional study, to be inversely proportional to cerebral blood flow (CBF). Serial longitudinal CBF and APCF data in Fontan patients taking into account brain injury (BI) has never been reported. Decreased CBF may adversely impact neurodevelopmental outcome.Methods:A prospective longitudinal cohort of 27 Fontan patients (age 10+1.9 years, 74% male) underwent cardiac and brain MRIs 3-9 months after Fontan and 6.0+1.86 years afterwards to measure CBF, APCF and to assess BI (grouped into focal brain injury (FBI), generalized insult (GI) and hemorrhage). CBF was measured using jugular venous flow and APCF was measured by the difference between aortic flow and caval return. A multivariate linear regression model was used to assess the relationship between change in APCF and change in CBF controlling for time since Fontan, sex, and changes in BI.Results:Demographics, flow and BI data are shown in table 1. A strong inverse relationship was found between CBF and APCF when CBF was indexed to aortic flow and APCF was indexed to BSA (R^2 = 0.72, P<0.01). Overall, CBF decreased by 9+11% and APCF decreased by 0.73+0.67 l/min/m^2 (12% when indexed to aortic flow). CBF and APCF were significantly and inversely related when adjusting for time since Fontan, sex, and change in the visibility of BI on MRI. Each one unit increase in APCF was associated with an 8% decrease in CBF. Change in CBF was smaller for those with longer times since Fontan and was larger for males. Change in CBF was larger for those whose FBI or GI became less visible, but smaller for those whose hemorrhages became less visible. See table 2.Conclusion:CBF and APCF are inversely related across serial imaging, adjusting for time from Fontan, sex and BI. This may adversely impact neurodevelopment. As APCs can be embolized, this may be a modifiable risk factor. A large scale trial is warranted.

Background: The SPARCC sacroiliac joint inflammation (SIS) and structural (SSS) scores are reliable measures to quantify abnormalities in the pediatric sacroiliac joint. We aimed to evaluate the utility of online calibration modules for the SIS and SSS and the reliability of their component change scores. Methods: Change score reliability of 6 raters was assessed by overall and pairwise intraclass correlation coefficients (ICCs) before and after the use of real-time iterative calibration (RETIC) modules for both the SIS and SSS comprised of 20 adult cases. Acceptable ICC for change scores was > 0.7 for SIS and > 0.5 for all SSS components. Sensitivity to change was assessed by the standardized response mean (SRM). Results: In scoring exercise 1, the SIS had acceptable reliability with a change score ICC of 0.80 and sclerosis was the only SSS lesion that met the acceptability threshold with a change score ICC of 0.52. After RETIC calibration, the SIS overall (ICC = 0.83) and mean pairwise (ICC = 0.83) change scores remained reliable with a large SRM (0.90). All SSS components except sclerosis met the overall and mean pairwise change score ICC acceptability thresholds—backfill: overall = 0.54, mean pairwise = 0.50; fat metaplasia: overall = 0.65, mean pairwise = 0.57; erosion: overall = 0.60, mean pairwise = 0.58; and ankylosis: overall = 0.96, mean pairwise = 0.96. The SSS RETIC module augmented the number of SSS components surpassing the acceptability threshold from 1 to 4. Sensitivity to change, as measured by the SRM, was large for erosion (0.96), moderate for backfill (0.55) and sclerosis (0.70), and small for fat metaplasia (0.36) and ankylosis (0.28). Conclusion: RETIC modules improved the overall reliability of SPARCC SIS and SSS change scores for previously calibrated raters. SIS recalibration was not as helpful to the most experienced raters who achieved high levels of agreement before recalibration. The SPARCC SIS and all SSS components except sclerosis are reliable measures to quantify change over time in children. A pediatric-specific RETIC tool should be developed to enhance the calibration of readers.

Introduction:Pulmonary regurgitation after surgical repair of tetralogy of Fallot (rToF) can result in progressive right ventricular (RV) dilatation and biventricular dysfunction leading to adverse clinical outcomes. Although pulmonary valve replacement (PVR) is considered to be critical for preservation of ventricular function, effects of PVR on ventricular strain are unknown. We aimed to assess the impact of PVR on ventricular mechanics in patients with rToF.Methods:Fifty five rToF patients who underwent cardiac magnetic resonance imaging (CMR) prior to and after PVR were assessed retrospectively. Global radial strain (GRS), global circumferential strain (GCS), and global longitudinal strain (GLS) were calculated by feature tracking analysis using combinations of short axis (sax) and 4-chamber view (4cv) images. Global measures of biventricular performance by CMR were also calculated.Results:Mean age at CMR prior to PVR was 19.2 ? 8.0 years old (yo), at PVR was 22.3 ? 7.5 yo, and at CMR after PVR was 26.4 ? 4.6 years old. Following PVR, RV GRS and GLS decreased (p < 0.001 and < 0.01, respectively), while LV GRS and GCS also significantly decreased (p < 0.01 and 0.02, respectively) (Fig. 1). As expected, following PVR, pulmonary regurgitation fraction (PRF), heart rate (HR), RV end-diastolic volume (EDV), RV end-systolic volume (ESV) and RV mass significantly declined with no significant change in RV ejection fraction (EF). In addition, left ventricular (LV) ESV, EDV, and mass significantly increased with no significant change in LVEF and LV cardiac index (CI) after PVR, demonstrating a beneficial ventricular-ventricular interaction (Table 1).Conclusions:Paradoxical decrease in biventricular strain is seen in rToF patients after PVR. This is most likely due to decreased need for RV contractility after abolition of RV volume overload and a more efficient geometry of LV contraction. Follow up strain studies will be needed for long term effects.

Introduction:Aortopulmonary collateral (APC) formation in single ventricle physiology is well known and associated with high morbidity which may include adverse neurodevelopmental outcome (NDO) because of the established inverse relationship between cerebral blood flow (CBF) and APC flow. How CBF changes in relation to APC flow as Fontan patients age remains unknown.Hypothesis:As Fontan patients age, APC flow decreases resulting in increased CBF.Methods:Patients with single ventricle after Fontan underwent serial cardiac magnetic resonance (CMR) 6-9 months after Fontan surgery and were followed up longitudinally 5-7 years later. CBF and APC flows were calculated using the phase contrast CMR in internal jugular veins, cavae, aorta (Ao), and pulmonary arteries and veins. Bivariate linear regression models for change in CBF indexed to BSA (?CBFBSA) and indexed to Ao flow (?CBFAo) were estimated. Statistical significance was taken at the 0.05 level.Results:Twenty-four (71% male) patients were enrolled. Mean age at Fontan was 3.37 years (SD: 1.31). A statistically significant inverse relationship between the change in CBF (?CBF) and the change in APC flow (?APC) was found (between ?CBFAoand ?APCBSA: estimate= -5.28, standard error [SE] = 2.47, p=0.043; between ?CBFAoand ?APCAo: estimate= -0.27, SE= 0.13, p=0.045). (Figure1 and 2). That is to say that as patients age, if their APC flow decreased, their CBF increased.Conclusions:Decreasing APC flow after Fontan results in increasing CBF, but this process can take years. Interventions to alter APC flow may improve CBF and thus potentially improve NDO; prospective investigation with a larger patient population is warranted.

Background:In the past 2 decades patients living with Fontan physiology have had improved life expectancy but continued high rates of morbidity. Alterations in flow equilibrium within this circulation are known to place patients at risk for Fontan morbidity. However little is known regarding how blood flow through the Fontan circuit changes over time. This study uses serial cardiac magnetic resonance (CMR) data to describe longitudinal trends in palliated single ventricle circulation.Methods:This was a retrospective single center study of all patients who underwent Fontan completion from 2008 to 2017 and underwent serial CMRs at ? 2 of the following time points: prior to Fontan, 3-9 months after Fontan and >1 year after Fontan. Flow was measured in the right (RSVC) and left superior vena cava (LSVC), inferior vena cava (IVC), Native Aorta, Neo-Aorta, right (RPA) and left pulmonary artery (LPA) indexed to BSA. Trends were studied using linear mixed effects models with random intercepts.Results:Sixty-three patients were studied; 18 had serial CMRs at 3 time points and 4 patients had MRIs at 4 time points. There was a linear increase in RPA and LPA flow and a linear decrease in SVC flow with time from Fontan (P=0.016 RPA, 0.009 LPA, 0.0001 SVC). Both neo-aortic and IVC flow decreased sharply in the first 1-2 years post Fontan however IVC flow increased after 2 years. This non-linear trend was statistically significant (P<0.0001 IVC, 0.0004 Neo Aorta).Systemic to pulmonary collateral flow decreased in a non-linear fashion the first year after Fontan (p < 0.0001).Conclusion:Serial data demonstrate specific longitudinal trends in vascular flow after conversion to a total cavopulmonary circulation. Early Fontan physiology is characterized a sharp decrease in IVC and neo-aortic flow, and linear increase in pulmonary artery flow over time. This data provides a framework with which serial CMR data can be used to identify patients who have abnormal adaptation to the Fontan circulation.

Introduction:Single right ventricular (SRV) morphology has been associated with adverse outcomes in Fontan patients. The impact of ventricular morphology on ventricular strain with the imposition of Fontan physiology is not well known. We sought to evaluate contractile function in single ventricle patients prior to and after Fontan surgery.Methods:SRV (n = 38) and single left ventricular (SLV) morphology (n = 11) underwent cardiac magnetic resonance imaging (CMR) prior to and after Fontan surgery. Global radial strain (GRS) and global circumferential strain (GCS) were calculated by feature tracking using the short axis and 4 chamber view images. Ejection Fraction (EF) and atrioventricular valve regurgitation (AVVR) were also measured.Results:Age at CMR prior to Fontan was 3.1 ? 1.3 years old (yo), at Fontan surgery was 3.4 ? 1.2 yo, and at CMR after Fontan was 5.8 ? 2.7 yo. GRS of SRV were significantly lower than SLV GRS both prior to (24.3 vs. 32.3%, p= 0.046) and after (21.8 vs. 30.6%, p= 0.03) Fontan. Although it didn?t reach statistical significance, mean SRV GCS were lower both prior to and after Fontan than SLV GCS. Both SRV GRS and SRV GCS deteriorated significantly after Fontan in contrast to SLV GRS and SLV GCS which did not (GRS; p< 0.01 and 0.61, GCS; p< 0.01 and 0.71, respectively) (Fig. 1A). There were no significant differences in EF between RV and LV both prior to and after Fontan, and EF didn?t deteriorate significantly after Fontan. While both GRS and GCS were not correlated with AVVR, EF was negatively correlated with AVVR both prior to (r = -0.30, p= 0.03) and after (r = -0.42, p< 0.01) Fontan (Fig. 1B).Conclusions:SRV strain are lower than SLV?s both prior to and after Fontan and deteriorates after Fontan surgery, whereas SLV strain does not. Our study suggests that strain measures can detect ventricular deterioration earlier than EF. In addition, the inverse correlation between AVVR and EF suggests that the single ventricle has lost ability to compensate for AVVR.

Introduction:Survivors of tetralogy of Fallot repair (TOF) can be left residua which may subject them to adverse outcomes. A large single center cohort with uniform surgery and imaging using cardiac magnetic resonance (CMR) measures may be able to predict these complications.Methods:Retrospective, single center study of all TOF survivors who underwent CMR from 2005-November 2017. CMR variables were extracted from reports or images analyzed. Medical and surgical history were obtained. Associations were tested using logistic or linear regression.Results:A total 667 TOF survivors underwent CMR (median 14.5 yo); 56% were male, 68% had routine TOF, 21% had TOF with pulmonary atresia, and 5% had TOF with absent pulmonary valve. Most (70%) had a transannular patch. With a mean followup of 4.8 +3.9 years, numerous CMR measures predicted adverse outcomes (Table). As in a previous multicenter trial, higher RV mass/volume was a significant risk factor for death, however, we also found that lower RV ejection fraction (EF) and left pulmonary artery (LPA) flow, were also significantly associated with death. Not surprisingly, higher RV volumes (in absolute terms and relative to the left ventricle (LV)) were associated with pulmonary valve replacement (PVR), however, lower RV EF was also associated with PVR. LV EF was associated with ventricular tachycardia (VT). For exercise, higher RV mass/volume predicted lower anaerobic threshold (? -140, P=.04) and higher LV volumes (? 1.1, P<.02) and cardiac index (CI) (? 14.2, P=.05) predicted greater maximum work. No risk factors were identified for hospitalization or pacemaker placement.Conclusions:In a large single center study, multiple CMR measures were associated with adverse outcomes in TOF survivors. RV mass/volume, EF and LPA flow were associated with greater odds of death; RV mass/volume also predicted lower anaerobic threshold. LV EF was associated with greater odds of VT. LV volumes and CI predicted greater maximum work.