Indications for cardiovascular magnetic resonance in children with congenital and acquired heart disease: an expert consensus paper of the Imaging Working Group of the AEPC and the Cardiovascular Magnetic Resonance Section of the EACVI

This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-making.

An unusual location of deep venous thrombosis associated with ischemic stroke and persistent foramen ovale

Up to 40% of ischemic strokes have no known cause (cryptogenic). The prevalence of persistent foramen ovale (PFO) amongst patients with cryptogenic stroke (CS) is twice as high as that of the normal population, therefore suggesting a causal relationship between the two entities. However, PFO by itself is not sufficient to cause stroke, as an embolic source is needed. This source is often unknown, making the causal relationship between CS and PFO hard to demonstrate. The most frequent, although still seldom, identifiable cause of embolism in an otherwise cryptogenic stroke associated with PFO is a deep venous thrombosis (DVT) of the lower extremities. Here, we present a unique case of brachiocephalic venous DVT associated with PFO and ischemic stroke in a young patient. As the search for DVT in patients with PFO and stroke is often limited to the lower extremities, this case may suggest that an unspecified number of DVTs are overlooked. Our report lends support to paradoxical embolism as a mechanism of stroke in patients with PFO and does, at least in selected cases, suggest a more detailed search for DVT beyond the lower extremities.

Transarterial and transvenous approach for transcatheter closure of a large coronary artery fistula with the Amplatzer vascular plug

Interventional occlusion of coronary artery fistulas has become a well-accepted alternative to surgical therapy. However, occlusion of high-flow lesions in children, necessitating implantation of large occluding devices, may be limited by the requirement of large delivery catheters. This report describes the interventional occlusion of a large coronary artery fistula in an 8-year-old girl. Complete occlusion was achieved by subsequent transvenous and transarterial implantation of two Amplatzer vascular plugs (AVP). The AVP is an interesting alternative for interventional occlusion of large coronary artery fistulas in children that can be deployed safely by rather small guiding catheters.

[Systematic evaluation of the proximal cardiac veins for echocardiographic diagnosis of total anomalous pulmonary venous connection]

PURPOSE

Total anomalous pulmonary venous connection (TAPVC) is a rare congenital cardiovascular malformation that is characterized by an absent connection of the pulmonary veins to the left atrium. Echocardiographic differentiation of TAPVC and persistent pulmonary hypertension of the newborn (PPHN) can be a great diagnostic challenge. The aim of our study was the assessment of a systematic echocardiographic approach to evaluate the feasibility and reliability of noninvasive diagnosis of TAPVC.

METHODS

Between January 1995 and January 2005, 15 consecutive patients with isolated TAPVC were diagnosed in our institution. 5 patients had supracardiac type, 5 cardiac type, 3 infracardiac and 2 had mixed type of TAPVC. Since 2001 preoperative diagnosis was performed exclusively by echocardiography (8/15 patients).

RESULTS

TAPVC could be diagnosed correctly in all cases using a systematic echocardiographic approach with careful investigation of the proximal cardiac veins. Infracardiac type ofTAPVC was diagnosed using systematic evaluation of the liver with visualization of a pathological vessel with venous flow directed away from the heart. In all cases the echocardiographic findings were confirmed during surgery.

CONCLUSION

Echocardiography with Doppler and color Doppler sonography is an effective method for noninvasive diagnosis of TAPVC. The presented systematic echocardiographic approach permits reliable noninvasive differentiation of TAPVC and PPHN.

[Dimenhydrinate overdosage in a 3(1/2) year-old-girl with dilative cardiomyopathy]

Dimenhydrinate overdosage in a 3(1/2) year-old-girl with dilative cardiomyopathy. Dimenhydrinate (Vomex(R)) is frequently used in the treatment of sickness and vomiting. The symptoms of overdosage present like an anticholinergic syndrome. We report on the clinical findings of an intoxication with dimenhydrinate in a 3(1/2) year-old-girl with functional dilative cardiomyopathy following a congenital left ventricular diverticle. Especially in small children, with the application of 40 mg suppositories once or twice per day the maximum dose of 3.75 mg/kgBW/d is achieved.

[Echocardiographic diagnosis of the aorto-pulmonary window]

PURPOSE/MATERIALS AND METHODS: The aorto-pulmonary window is a rare congenital cardiac malformation consisting of a connection between the ascending aorta and the main pulmonary artery. Based on 5 consecutive patients who were treated in our tertiary referral centre between 7/2000 and 11/2005, we report the echocardiographic features as well the limitations of this diagnostic method in the assessment of this rare malformation.

RESULTS

Dilation of the left atrium and ventricle due to the large left-to-right-shunt was the characteristic echocardiographic feature in all patients with aorto-pulmonary window. In all patients we were able to visualise the window by 2D-echocardiography. Pulsed- and continuous-wave Doppler showed diastolic negative flow in the descending aorta and in systemic arteries due to left-to-right shunting in diastole via the aorto-pulmonary window. All 5 patients had significant associated cardiovascular malformations. They were accurately diagnosed by echocardiography. Coronary anomalies could be excluded noninvasively in all patients.

CONCLUSION

Echocardiography is the method of choice for diagnosis of aortopulmonary window. Detection of aortopulmonary window, however, requires a systematic and careful investigation of all cardiovascular anatomic details, since this anomaly is frequently associated with substantial additional cardiac anomalies, which would by themselves be sufficient to explain the haemodynamic abnormalities of the patient. Cardiac catheterisation is required only in cases with inadequate information about coronary artery anatomy or in older patients with pulmonary hypertension, to determine the patient's suitability for surgical correction.

Stereolithographic reproduction of complex cardiac morphology based on high spatial resolution imaging

BACKGROUND

Precise knowledge of cardiac anatomy is mandatory for diagnosis and treatment of congenital heart disease. Modern imaging techniques allow high resolution three-dimensional (3D) imaging of the heart and great vessels. In this study stereolithography was evaluated for 3D reconstructions of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) data.

METHODS

A plastinated heart specimen was scanned with MDCT and after segmentation a stereolithographic (STL) model was produced with laser sinter technique. After scanning the STL model with MDCT these data were compared with those of the original specimen after rigid registration using the iterative closest points algorithm (ICP). The two surfaces of the original specimen and STL model were matched and the symmetric mean distance was calculated. Additionally, the heart and great vessels of patients (age range 41 days-21 years) with congenital heart anomalies were imaged with MDCT (n=2) or free breathing steady, state free-precession MRI (n=3). STL models were produced from these datasets and the cardiac segments were analyzed by two independent observers.

RESULTS

All cardiac structures of the heart specimen were reconstructed as a STL model within sub-millimeter resolution (mean surface distance 0.27+/-0.76 mm). Cardiac segments of the STL patient models were correctly analyzed by two independent observers compared to the original 3D datasets, echocardiography (n=5), x-ray angiography (n=5), and surgery (n=4).

CONCLUSIONS

High resolution MDCT or MRI 3D datasets can be accurately reconstructed using laser sinter technique. Teaching, research and preoperative planning may be facilitated in the future using this technique.

Recanalisation of bilateral superior vena cava after total cavopulmonary connection. Interventional occlusion with the Amplatzer VSD Occluder

Formation of systemic to pulmonary venous or systemic venous left atrial collaterals frequently occurs in patients after Glenn or Fontan-type operations. Embolization with detachable metal coils is the therapy of choice for the closure of small vessels. These devices however are not appropriate for the occlusion of large collaterals, e. g. recanalized bilateral caval veins. We report two patients who presented late after Fontan-type operations with a gradual decrease in oxygen saturation due to recanalisation of bilateral caval veins. Interventional closure of these large veins was carried out successfully with the use of 8 mm Amplatzer muscular VSD Occluders, resulting in an increase of arterial oxygen saturations.

CONCLUSION

The closure of recanalized bilateral superior caval veins after Fontan procedures is possible without technical problems by means of the Amplatzer muscular VSD Occluder. In order to avoid future formation of venous collaterals via the azygos or hemiazgos system, the occluder should be placed in the vena cava below the orifice of the azygos/ hemiazygos vein.

Stellenwert einer parameteroptimierten 3D-FISP-MR-Angiographie bei Kindern mit Aortenisthmusstenose im Vergleich zur Katheterangiographie

PURPOSE

To implement parameter-optimized 3D-FISP MR angiography (MRA) with interleaved double-slab excitation and to compare the result with catheter angiography in children with aortic coarctation.

MATERIALS AND METHODS

Eighteen children aged 2 - 15 years (mean 9.1 years) underwent MR imaging on a 1.5T body scanner (Magnetom Vision, Siemens, Germany). All patients had undergone correlative catheter angiography. T1-weighted turbo spin echo (TSE) images (TR 600 ms, TE 17 ms, flip 160 degrees, slice thickness 2 - 4 mm) were obtained in axial and parasagittal orientation, followed by an optimized 3D-FISP MR angiography in a sagittal plane (TR 12.5 ms, TE 5.5 ms, flip 22 degrees, matrix 256 x 256, slice thickness 1.25 mm). All children were sedated but on spontaneous breathing. Image quality was graded by two experienced reviewers using a 4-point scoring system. Source images and reformatted maximum intensity projections (MIP) were analyzed for blood-tissue contrast as well as size and focal stenoses of the aortic arch.

RESULTS

Aortic coarctation was found in 13 of 18 patients, using the 3D-FISP MRA. A high correlation value (r = 0.96) was found compared to catheter angiography. Image quality was high in 94 % with well defined blood-tissue contrast in all cases. The sensitivity to flow and breathing motion was low. Examination time was about 15 minutes depending on volume of interest and heart rate. Diagnostic accuracy has shown improvement using a combined analysis of source and MIP images. The mentioned technique has provided an excellent display of thoracic vasculature.

CONCLUSION

MR imaging represents an excellent tool for non-invasive examination of the cardiovascular system of children. The 3D-MRA allows the recording of a large 3D data set without the use of contrast agent and within an adequate measurement period, particularly in small infants unable to hold their breath. In addition, hemodynamic significance of aortic coarctation, the existence of collateral vessels and other congenital heart diseases can be described reliably by using this technique.

Asymptomatisches Cor triatriatum bei einer 2� Jahre alten Patientin

We report on an asymptomatic 2 1/4 year old girl. Echocardiography revealed cor triatriatum with a membrane separating the left atrium. Transesophageal echocardiography demonstrated 3 large perforations of the intraatrial membrane. Using Doppler sonography, no pressure gradients across these orifices were identified. Obstruction of the intraatrial membrane and pulmonary hypertension were excluded by cardiac catheterization. We therefore decided against surgical resection of the membrane and to follow the patient noninvasively by echocardiography. Follow-up over 18 months revealed no development of an obstruction across the intraatrial membrane. Our case shows that immediate surgical correction is not necessary in all patients with cor triatriatum. Conservative management of these patients requires full evaluation of the hemodynamics and careful follow-up examinations by echocardiography.

Prenatal diagnosis and perinatal management of left coronary artery to right atrium fistula

Serious complications due to coronary artery fistulae have been described. Most authors recommend early intervention at the time of diagnosis. We present a case of a fistula originating from a dilated left coronary artery and draining into the right atrium, which was diagnosed prenatally by color Doppler echocardiography. During pregnancy, the echocardiographic findings remained unchanged, and there were no signs of heart failure. After birth, the fistula was confirmed by angiography. Additionally, a persistent left superior vena cava draining into the coronary sinus and a very small ventricular septal defect were detected. The fistula was closed successfully by transcatheter coil embolization. At 17 months old the child was in good clinical condition. Prenatal diagnosis of coronary artery fistulae may be possible and may improve perinatal management and outcome.

[Echocardiographic findings before and after interventional occlusion of persistently patent ductus arteriosus with the amplatzer duct occluder]

AIM

The Amplatzer duct occluder(R) is a new system for interventional occlusion of persistently patent ductus arteriosus. The purpose of our study was to determine, whether adequate evaluation of this occluder system can be obtained by echocardiography.

METHOD

From 11/1999 until 12/2000, 18 patients were included in the study. All underwent interventional occlusion of a patent ductus arteriosus with the Amplatzer duct occluder(R). Echocardiography was performed on admission, on day one and three and six months following the intervention.

RESULTS

The mean age of our patients was 4.8 years (9 months - 18.7 years, median 3.2 years), the mean weight was 18.4 kg (6.5 - 66 kg, median 14 kg). All echocardiographic findings prior to intervention were confirmed during cardiac catheterization. Following intervention we were able to visualize the occluder system and its relation to surrounding structures in all patients. In none of our patients we found an obstruction of the left pulmonary artery. In 1/18 patients there was a minor protrusion of the distal occluder into the descending aorta. Doppler-sonography however revealed no obstruction. Complete occlusion of the ductus arteriosus was confirmed by color Doppler echocardiography in all patients within 5 days, in 17/18 patients no residual shunt was detectable within 24 hours.

CONCLUSION

According to our experience the results of interventional occlusion of patent ductus arteriosus in children and adolescents can be well determined by echocardiography.