Contrast-enhanced magnetic resonance angiography of the great arteries in patients with congenital heart disease: an accurate tool for planning catheter-guided interventions

Background: Catheter-guided interventions are increasingly used for relief of lesions in patients with congenital heart disease. Exact anatomical imaging with measurement of the vascular structures is crucial in the planning of such interventions. This can be provided non-invasively and without radiation by contrast-enhanced MR angiography (CE-MRA). Aim: To evaluate the accuracy of the measurements of the vessels obtained by CE-MRA in comparison to those obtained by conventional X-ray angiography (XRA). Methods: Measurements of the diameters of aorta and pulmonary arteries were performed retrospectively and blinded on the CE-MRA and XRA images, in comparable locations. The limits of agreement between the two methods were calculated. Results: Twenty-one CE-MRA and XRA were performed in 20 children with congenital heart disease, median age 4years (1day-13years), weight 18kg (3.2-74kg). The time interval between CE-MRA and XRA was 2.6 ± 2.3months. A total of 98 measurements, 38 of the aorta and 60 of the pulmonary arteries were performed on the images obtained by each technique. The correlation between CE-MRA and XRA measurements was excellent, r=0.97, p < 0.0001. The mean difference between the two techniques was 0.018 ± 1.1mm; the limits of agreement −2.14 and + 2.18mm. Similar agreement was found for measures of the aorta (r=0.97, mean difference 0.20 ± 1.08mm) and of the pulmonary arteries (r=0.97, mean difference 0.048 ± 0.89mm). Conclusions: CE-MRA provides accurate quantitative anatomical information, which highly agrees with XRA data, and can therefore be used for planning catheter-guided procedure

Pericarditis constrictiva in a 10-year-old boy after influenza A virus infection

Pericarditis constrictiva is caused by fibrotic degeneration of the pericardium and leads to impaired diastolic ventricular filling. The diagnosis of constrictive pericarditis in children remains challenging and often requires a multimodal approach. We present a case of a pericarditis constrictiva in a 10-year old boy after influenza A virus infection. Clinicians should be aware of this complication, especially in patients with symptoms of exertional dyspnea and congestive heart failure

Signal Thresholding Segmentation of Ventricular Volumes in Young Patients with Various Diseases—Can We Trust the Numbers?

In many cardiac diseases, right and left ventricular volumes in systole and diastole are diagnostically and prognostically relevant. Measurements are made by segmentation of the myocardial borders on cardiac magnetic resonance (CMR) images. Automatic detection of myocardial contours is possible by signal thresholding techniques, but must be validated before use in clinical settings. Biventricular volumes were measured in end-diastole (EDVi) and in end-systole (ESVi) both manually and with the MassK application, with signal thresholds at 30%, 50%, and 70%. Stroke volumes (SV) and cardiac indices (CI) were calculated from volumetric measurements and from flow measured in the ascending aorta and the main pulmonary artery, and both methods were compared. Reproducibility of volumetric measurements was tested in 20 patients. Measurements were acquired in 94 patients aged 15 ± 9 years referred for various conditions. EDVi and ESVi of both ventricles were largest with manual segmentation and inversely proportional to the MassK threshold. Manual and k30 SV and CI corresponded best to flow measurements. Interobserver variability was low for all volumes manually and with MassK. In conclusion, manual and 30% threshold-based biventricular volume segmentation agree best with two-dimensional, phantom-corrected phase contrast flow measurements in a young cardiac referral population and are well reproducible

Quantitative evaluation of aortic valve regurgitation in 4D flow cardiac magnetic resonance: at which level should we measure?

PURPOSE To find the best level to measure aortic flow for quantification of aortic regurgitation (AR) in 4D flow CMR. METHODS In 27 congenital heart disease patients with AR (67% male, 31 ± 16 years) two blinded observers measured antegrade, retrograde, net aortic flow volumes and regurgitant fractions at 6 levels in 4D flow: (1) below the aortic valve (AV), (2) at the AV, (3) at the aortic sinus, (4) at the sinotubular junction, (5) at the level of the pulmonary arteries (PA) and (6) below the brachiocephalic trunk. 2D phase contrast (2DPC) sequences were acquired at the level of PA. All patients received prior transthoracic echocardiography (TTE) with AR severity grading according to a recommended multiparametric approach. RESULTS After assigning 2DPC measurements into AR grading, agreement between TTE AR grading and 2DPC was good (κ = 0.88). In 4D flow, antegrade flow was similar between the six levels (p = 0.87). Net flow was higher at level 1-2 than at levels 3-6 (p < 0.05). Retrograde flow and regurgitant fraction at level 1-2 were lower compared to levels 3-6 (p < 0.05). Reproducibility (inter-reader agreement: ICC 0.993, 95% CI 0.986-0.99; intra-reader agreement: ICC 0.982, 95%CI 0.943-0.994) as well as measurement agreement between 4D flow and 2DPC (ICC 0.994; 95%CI 0.989 - 0.998) was best at the level of PA. CONCLUSION For estimating severity of AR in 4D flow, best reproducibility along with best agreement with 2DPC measurements can be expected at the level of PA. Measurements at AV or below AV might underestimate AR

Myocardial Deformation in Fontan Patients Assessed by Cardiac Magnetic Resonance Feature Tracking: Correlation with Function, Clinical Course, and Biomarkers

Cardiac MR (CMR) is a standard modality for assessing ventricular function of single ventricles. CMR feature-tracking (CMR-FT) is a novel application enabling strain measurement on cine MR images and is used in patients with congenital heart diseases. We sought to assess the feasibility of CMR-FT in Fontan patients and analyze the correlation between CMR-FT strain values and conventional CMR volumetric parameters, clinical findings, and biomarkers. Global circumferential (GCS) and longitudinal (GLS) strain were retrospectively measured by CMR-FT on Steady-State Free Precession cine images. Data regarding post-operative course at Fontan operation, and medication, exercise capacity, invasive hemodynamics, and blood biomarkers at a time interval ± 6 months from CMR were collected. Forty-seven patients underwent CMR 11 ± 6 years after the Fontan operation; age at CMR was 15 ± 7 years. End-diastolic volume (EDV) of the SV was 93 ± 37 ml/m2, end-systolic volume (ESV) was 46 ± 23 ml/m2, and ejection fraction (EF) was 51 ± 11%. Twenty (42%) patients had a single right ventricle (SRV). In single left ventricle (SLV), GCS was higher (p < 0.001), but GLS was lower (p = 0.04) than in SRV. GCS correlated positively with EDV (p = 0.005), ESV (p < 0.001), and EF (p ≤ 0.0001). GLS correlated positively with EF (p = 0.002), but not with ventricular volumes. Impaired GCS correlated with decreased ventricular function (p = 0.03) and atrioventricular valve regurgitation (p = 0.04) at echocardiography, direct atriopulmonary connection (p = 0.02), post-operative complications (p = 0.05), and presence of a rudimentary ventricle (p = 0.01). A reduced GCS was associated with increased NT-pro-BNP (p = 0.05). Myocardial deformation can be measured by CMR-FT in Fontan patients. SLVs have higher GCS, but lower GLS than SRVs. GCS correlates with ventricular volumes and EF, whereas GLS correlates with EF only. Myocardial deformation shows a relationship with several clinical parameters and NT-pro-BNP. Keywords: Biomarkers; CMR; CMR-FT; Fontan; Strai

Possible effects of left pulmonary artery stenting in single ventricle patients on bronchial area, lung volume and lung function

BACKGROUND Left pulmonary artery (LPA) stenting is often required in single ventricle (SV) patients. Due to their close anatomical relationship an LPA stent could potentially compress the left main bronchus (LMB). We assessed the impact of LPA stenting on bronchial size, pulmonary volumes, and lung function in a cohort of SV patients. METHODS Forty-nine patients underwent cardiovascular magnetic resonance (CMR) and 36 spirometry 11 (8-15) years after Fontan. All patients were free of respiratory symptoms. LPA stents were inserted in 17 (35%) patients at 8.8 (3.4-12.6) years. Area/shape of the main bronchi (n = 46) and lung volumes (n = 47) were calculated from CMR-ZTE images for each lung and transformed in right-to-left (r/l) ratio and indexed for BSA. The effect of early stent insertion (prior to stage III) was analyzed. RESULTS Patients with LPA stent had larger r/l ratio for main bronchus area (p < 0.001) and r/l ratio difference for lung volumes was slightly larger in patients with early stenting. A trend toward a deformation of LMB shape in patients with LPA stent and toward a higher prevalence of abnormal spirometry in patients with early stent implantation was observed. CONCLUSIONS In this cohort of patients, early insertion of LPA stents seems to relate with smaller LMB sizes and a trend toward smaller left lung volume and higher prevalence of impaired lung function. Whether these findings are caused by the stent or, at least to a certain degree, present prior to the implantation needs to be verified

Nicht invasive Bildgebung in der Kinderkardiologie

Nach einer sorgfältigen Anamnese und klinischen Untersuchung spielt die transthorakale Echokardiografie die grösste Rolle für die Diagnose angeborener Herzfehler. Invasive Abklärungen sind nur sehr selten indiziert

Congenital cardiac defects and MR-guided planning of surgery

In neonates and infants with congenital heart disease (CHD), cardiovascular magnetic resonance (CMR) is an established imaging modality in all patients in whom echocardiography does not provide sufficient information and definitive diagnosis. CMR is noninvasive, and does not involve vascular catheterization or ionizing radiation. Therefore the use of CMR obviates the potential risks of cardiac catheterization in critically ill infants. This article discusses the use of CMR in newborns with CHD before cardiac surgery, focusing on conotruncal anomalies, pulmonary venous anomalies, complex CHD in visceroatrial heterotaxy, borderline hypoplastic left heart syndrome, and the use of contrast medium in newborns