Cardiac imaging: MR or CT? Which to use when

Cardiovascular Magnetic Resonance from Fetal to Adult Life-Indications and Challenges: A State-of-the-Art Review

Cardiovascular magnetic resonance (CMR) imaging offers a comprehensive, non-invasive, and radiation-free imaging modality, which provides a highly accurate and reproducible assessment of cardiac morphology and functions across a wide spectrum of cardiac conditions spanning from fetal to adult life. It minimises risks to the patient, particularly the risks associated with exposure to ionising radiation and the risk of complications from more invasive haemodynamic assessments. CMR utilises high spatial resolution and provides a detailed assessment of intracardiac and extracardiac anatomy, ventricular and valvular function, and flow haemodynamic and tissue characterisation, which aid in the diagnosis, and, hence, with the management of patients with cardiac disease. This article aims to discuss the role of CMR and the indications for its use throughout the different stages of life, from fetal to adult life.

Neonatal cardiorespiratory imaging-a multimodality state-of-the-art review

Advanced cardiorespiratory imaging of the chest with ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI) plays an important role in diagnosing respiratory and cardiac conditions in neonates when radiography and echocardiography alone are not sufficient. This pictorial essay highlights the particularities, clinical indications and technical aspects of applying chest US, cardiac CT and cardiorespiratory MRI techniques specifically to neonates, summarising the first session of the European Society of Paediatric Radiology's cardiothoracic task force.

Diagnostic performance of 320 cardiac MDCT angiography in assessment of PDA either isolated or associated with duct dependent congenital heart disease

Background

Patent ductus arteriosus (PDA) is one of most common congenital heart defects, it's a unique vascular structure that provides direct communication between pulmonary and systemic circulation. MDCT angiography is a good imaging modality for evaluation of the PDAs and detection of their exact morphological type; course and diameters, which is important before percutaneous closure or stenting procedure of the PDA, also for selection of closure hardware. The aim of this study was to assess the role of MDCT angiography in qualitative and quantitative evaluation of PDA and associated cardiac and\or extracardiac anomalies.

Results

Echocardiography detected PDA in 28\30 cases while cardiac MDCT detected PDA in all studied 30 cases confirmed by cardiac catheterization and/or operation. MDCT angiography had sensitivity 100% and specificity 100% for PDA detection. PDA originated from aortic isthmus in 15 cases, inferior surface of aortic arch in 11 cases and innominate artery in 4 cases. The most common morphological type of PDA was type A (cone\46.67%) followed by type C (tubular\23.3%), type D (complex\10%), type E (elongated\13.33%) and type B (window\6.67%). The spearman correlation coefficient test demonstrated poor correlation between size of aortic end and MPA (P = 0.75), and between size of pulmonary end and diameter of MPA (P = 0.99) and also demonstrated fair correlation between length of PDA and MPA (P = 0.018). PDA was isolated in 4\30 cases and associated with cardiac and\or extra cardiac anomalies in 26\30 cases included; ASD (n = 18), VSD (n = 16), pulmonary atresia (n = 7), transposition of great arteries (n = 5), teratology of Fallot (n = 4), aortic coarctation (n = 4), persistent truncus arteriosus (n = 3), tricuspid atresia (n = 3), anomalous of pulmonary venous return (n = 3), hypoplastic segment of aorta (n = 2), Ebstein's anomaly (n = 1), bicuspid aortic arch (n = 1) and left hypoplastic heart syndrome (n = 1).

Conclusion

Cardiac MDCT angiography was superior to Echocardiography in detection, quantitative and qualitative evaluation of PDA either isolated or associated with congenital cardiac and\or extracardiac anomalies and was superior to Echocardiography in detection of associated extracardiac anomalies rather than associated intra cardiac anomalies.

Cardiac computed tomography angiography in the pre-operative assessment of congenital heart disease in Thailand

Introduction

Cardiac computed tomography angiography (CCTA) plays a vital role in clinical practice in evaluating patients with congenital heart disease (CHD) when the information from echocardiography is equivocal.

Aim

To test the hypothesis that CCTA has significantly value for pre-operative evaluation of congenital heart disease and practicality in the diagnosis and management of congenital heart disease patients at our tertiary care academic hospital.

Material and methods

We studied a total of 78 congenital heart disease patients (median age: 4.5 years) who had undergone CCTA during the period January 2017 to October 2018 at our tertiary care academic hospital.

Results

The results were classified as diagnostic categories, and the impact of the procedure on strategizing management was analysed. In each group, the CCTA offered an advantage and provided specific clues for surgical or interventional management. In total, the sensitivity (97.5%), specificity (100%), positive predictive value (100%), negative predictive value (99.38%), and accuracy (99.5%) of CCTA, for which the significant findings were confirmed by surgical or cardiac catheterization, were excellent, with average exposure per CCTA study calculated at 1.41 (0.36–3.28) mSv.

Conclusions

CCTA is an excellent non-invasive modality for the evaluation of congenital heart disease patients, with an important diagnostic and decision-aiding role.

MDCT angiographic findings of various congenital pulmonary artery anomalies in pediatric patients

Background

Congenital pulmonary artery anomalies are variable and need proper diagnosis and treatment. CT angiography with multiplanar reconstruction has the main role in the assessment of these anomalies and this non-invasive method should be the method of choice for preoperative planning and postoperative follow up.

The aim of the study is to assess the value of MDCT in the detection of pulmonary arteries anomalies in the pediatric population with complex congenital heart disease in conjunction with echocardiography as an alternative to conventional angiography and to determine the superiority of MDCT in the assessment of other abnormalities such as airway anomalies.

Results

In our retrospective study, 52 patients (28 male and 24 females, aged 1 day to 4 years: mean age 2 years) were examined with contrast-enhanced CT. CT examinations were done using a 128-section CT scanner (Siemens Somatom Definition AS) using non-ionic iodinated contrast media. 2D and 3D reconstructions were performed. The correlation was made with echocardiograms. All imaging studies were reviewed. The echo was done to all patients. Surgery and/or catheter angiography performed to all patients, their findings were reviewed and compared to CTA findings. Other abnormalities such as congenital airway anomalies are detected using axial MDCT images and reconstructed imaging techniques.

MDCT was accurate in revealing pulmonary artery anomalies. The commonest pulmonary artery anomaly was atresia, stenosis then hypoplasia. These anomalies may be isolated or associated with other congenital heart diseases. In the current study, MDCT could diagnose all cases of pulmonary arterial anomalies with 96% sensitivity, 100% specificity, 98% accuracy, 100% positive, and 94% negative predictive values. CT scans provide accurate information to assess complex spatial relationships of vascular airway compression frequently associated with CHD in the pediatric population.

Conclusion

MDCT scanner can be an alternative to diagnostic conventional angiography for the non-invasive assessment of the pulmonary artery. Higher quality multiplanar and 3D reconstruction achieved by the MDCT scanners offer a rapid, reliable and non-invasive technique that can be used for the evaluation and preoperative assessment of thoracic vascular and extra-vascular anatomy in infants and children with suspected congenital heart disease. CT technologies are constantly developing collaboration between radiologists, pediatric cardiologists, and anesthesiologists, which is essential for improving CT performance.

High-quality low-dose cardiovascular computed tomography (CCT) in pediatric patients using a 64-slice scanner

Background Cardiovascular computed tomography (CCT) technology is rapidly advancing allowing to perform good quality examinations with a radiation dose as low as 1.2 mSv. However, latest generation scanners are not available in all centers. Purpose To estimate radiation dose and image quality in pediatric CCT using a standard 64-slice scanner. Material and Methods A total of 100 patients aged 6.9 ± 5.4 years (mean ± standard deviation) who underwent a 64-slice CCT scan using 80, 100, or 120 kVp, were retrospectively evaluated. Radiation effective dose was calculated on the basis of the dose length product. Two independent readers assessed the image quality through signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and a qualitative score (3 = very good, 2 = good, 1 = poor). Non-parametric tests were used. Results Fifty-five exams were not electrocardiographically (ECG) triggered, 20 had a prospective ECG triggering, and 25 had retrospective ECG triggering. The median effective dose was 1.3 mSv (interquartile range [IQR] = 0.8-2.7 mSv). Median SNR was 30.6 (IQR = 23.4-33.6) at 120 kVp, 29.4 (IQR = 23.7-34.8) at 100 kVp, and 24.7 (IQR = 19.4-34.3) at 80 kVp. Median CNR was 21.0 (IQR = 14.8-24.4), 19.1 (IQR = 15.6-23.9), and 25.3 (IQR = 19.4-33.4), respectively. Image quality was very good, good, and poor in 56, 39, and 5 patients, respectively. No significant differences were found among voltage groups for SNR ( P = 0.486), CNR ( P = 0.336), and subjective image quality ( P = 0.296). The inter-observer reproducibility was almost perfect (κ = 0.880). Conclusion High-quality pediatric CCT can be performed using a 64-slice scanner, with a radiation effective dose close to 2 mSv in about 50% of the cases.

Catheter, MRI and CT Imaging in Newborns with Pulmonary Atresia with Ventricular Septal Defect and Aortopulmonary Collaterals: Quantifying the Risks of Radiation Dose and Anaesthetic Time

A comprehensive understanding of the native pulmonary blood supply is crucial in newborns with pulmonary atresia with ventricular septal defect and aortopulmonary collaterals (PA/VSD/MAPCA). We sought to describe the accuracy in terms of identifying native pulmonary arteries, radiation dose and anaesthetic time associated with multi-modality imaging in these patients, prior to their first therapeutic intervention. Furthermore, we wanted to evaluate the cumulative radiations dose and anaesthetic time over the study period. Patients with PA/VSD/MAPCA diagnosed at < 100 days between 2004 and 2014 were identified. Cumulative radiation dose and anaesthetic times were calculated, with imaging results compared with intraoperative findings. We then calculated the cumulative risks to date for all surviving children. Of 19 eligible patients, 2 had echocardiography only prior to first intervention. The remaining 17 patients underwent 13 MRIs, 4 CT scans and 13 cardiac catheterization procedures. The mean radiation dose was 169 mGy cm² (47-461 mGy cm²), and mean anaesthetic time was 111 min (33-185 min). 3 children had MRI only with no radiation exposure, and one child had CT only with no anaesthetic. Early cross-sectional imaging allowed for delayed catheterisation, but without significantly reducing radiation burden or anaesthetic time. The maximum cumulative radiation dose was 8022 mGy cm² in a 6-year-old patient and 1263 min of anaesthetic at 5 years. There is the potential to generate very high radiation doses and anaesthetic times from diagnostic imaging alone in these patients. As survival continues to improve in many congenital heart defects, the important risks of serial diagnostic imaging must be considered when planning long-term management.

Radiation dose management for pediatric cardiac computed tomography: a report from the Image Gently 'Have-A-Heart' campaign

Children with congenital or acquired heart disease can be exposed to relatively high lifetime cumulative doses of ionizing radiation from necessary medical imaging procedures including radiography, fluoroscopic procedures including diagnostic and interventional cardiac catheterizations, electrophysiology examinations, cardiac computed tomography (CT) studies, and nuclear cardiology examinations. Despite the clinical necessity of these imaging studies, the related ionizing radiation exposure could pose an increased lifetime attributable cancer risk. The Image Gently "Have-A-Heart" campaign is promoting the appropriate use of medical imaging studies in children with congenital or acquired heart disease while minimizing radiation exposure. The focus of this manuscript is to provide a comprehensive review of radiation dose management and CT performance in children with congenital or acquired heart disease.

Radiation dose reduction in pediatric great vessel stent computed tomography using iterative reconstruction: A phantom study

BACKGROUND

To study dose reduction using iterative reconstruction (IR) for pediatric great vessel stent computed tomography (CT).

METHODS

Five different great vessel stents were separately placed in a gel-containing plastic holder within an anthropomorphic chest phantom. The stent lumen was filled with diluted contrast gel. CT acquisitions were performed at routine dose, 52% and 81% reduced dose and reconstructed with filtered back projection (FBP) and IR. Objective image quality in terms of noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) as well as subjective image quality were evaluated.

RESULTS

Noise, SNR and CNR were improved with IR at routine and 52% reduced dose, compared to FBP at routine dose. The lowest dose level resulted in decreased objective image quality with both FBP and IR. Subjective image quality was excellent at all dose levels.

CONCLUSION

IR resulted in improved objective image quality at routine dose and 52% reduced dose, while objective image quality deteriorated at 81% reduced dose. Subjective image quality was not affected by dose reduction.

Imaging of pediatric great vessel stents: Computed tomography or magnetic resonance imaging?

Background

Complications might occur after great vessel stent implantation in children. Therefore follow-up using imaging is warranted.

Purpose

To determine the optimal imaging modality for the assessment of stents used to treat great vessel obstructions in children.

Material and methods

Five different large vessel stents were evaluated in an in-vitro setting. All stents were expanded to the maximal vendor recommended diameter (20mm; n = 4 or 10mm; n = 1), placed in an anthropomorphic chest phantom and imaged with a 256-slice CT-scanner. MRI images were acquired at 1.5T using a multi-slice T₂-weighted turbo spin echo, an RF-spoiled three-dimensional T₁-weighted Fast Field Echo and a balanced turbo field echo 3D sequence. Two blinded observers assessed stent lumen visibility (measured diameter/true diameter *100%) in the center and at the outlets of the stent. Reproducibility of diameter measurements was evaluated using the intraclass correlation coefficient for reliability and 95% limits of agreement for agreement analysis.

Results

Median stent lumen visibility was 88 (IQR 86–90)% with CT for all stents at both the center and outlets. With MRI, the T₂-weighted turbo spin echo sequence was preferred which resulted in 82 (78–84%) stent lumen visibility. Interobserver reliability and agreement was good for both CT (ICC 0.997, mean difference -0.51 [-1.07–0.05] mm) and MRI measurements (ICC 0.951, mean difference -0.05 [-2.52 –-2.41] mm).

Conclusion

Good in-stent lumen visibility was achievable in this in-vitro study with both CT and MRI in different great vessel stents. Overall reliability was good with clinical acceptable limits of agreement for both CT and MRI. However, common conditions such as in-stent stenosis and associated aneurysms were not tested in this in-vitro study, limiting the value of the in-vitro study.

Cardiovascular magnetic resonance: Diagnostic utility and specific considerations in the pediatric population

Cardiovascular magnetic resonance is a non-invasive imaging modality which is emerging as important tool for the investigation and management of pediatric cardiovascular disease. In this review we describe the key technical and practical differences between scanning children and adults, and highlight some important considerations that must be taken into account for this patient population. Using case examples commonly seen in clinical practice, we discuss the important clinical applications of cardiovascular magnetic resonance, and briefly highlight key future developments in this field.

Induced apnea enhances image quality and visualization of cardiopulmonary anatomic during contrastenhanced cardiac computerized tomographic angiography in children

Objective:

The purpose of our study was to determine the effect of induced apnea on quality of cardiopulmonary structures during computerized tomographic (CT) angiography images in children with congenital heart diseases.

Methods:

Pediatric patients with congenital heart defects undergoing cardiac CT angiography at our facility in the past 3 years participated in this study. The earlier patients underwent cardiac CT angiography without induced apnea and while, later, apnea was induced in patients, which was followed by electrocardiogram gated cardiac CT angiography. General anesthesia was induced using sleep dose of intravenous propofol. After the initial check CT, on request by the radiologist, apnea was induced by the anesthesiologist by administering 1 mg/kg of intravenous suxamethonium. Soon after apnea ensued, the contrast was injected, and CT angiogram carried out. CT images in the “apnea group” were compared with those in “nonapnea group.” After the completion of the procedure, the patients were mask ventilated with 100% oxygen till the spontaneous ventilation was restored.

Results:

We studied 46 patients, of whom 36 with apnea and yet another 10 without. The quality of the image, visualization of structures such as cardiac wall, outflow tracts, lung field, aortopulmonary shunts, and coronary arteries were analyzed and subjected to statistical analysis (Mann–Whitney U, Fischer's exact test and Pearson's Chi-square test). In the induced apnea group, overall image quality was considered excellent in 89% (n = 33) of the studies, while in the “no apnea group,” only 30% of studies were excellent. Absent or minimal motion artifacts were seen in a majority of the studies in apnea group (94%). In the nonapnea group, the respiratory and body motion artifacts were severe in 50%, moderate in 30%, and minimal in 20%, but they were significantly lesser in the apnea group. All the studied parameters were statistically significant in the apnea group in contrast to nonapnea group (P < 0.000).

Conclusion:

The image quality of cardiac CT angiography greatly improves, and motion artifact significantly decreases with the use of induced apnea in pediatrics patients being evaluated for congenital heart disease. This technique poses no additional morbidity of significance.

Imaging modalities in children with vascular ring and pulmonary artery sling

PURPOSE

Our aim is to compare new non-invasive imaging modalities in the evaluation of vascular ring (VR) and pulmonary artery sling (PAS) and to understand the role of bronchoscopy in comparison with them in assessing tracheobronchial tree.

METHODS

We have retrospectively analyzed the data from 41 patients with a VR or a PAS diagnosed at Bambino Gesù Children's Hospital of Rome, between 2008 and 2012. Age, gender, presenting symptoms, clinical history, comorbidities, imaging modalities used for diagnosis (cardiac magnetic resonance [CMR], computed tomography [CT], tracheobronchoscopy [TB]) and surgical treatment were recorded.

RESULTS

The vascular anatomy was completely defined in all patients, whether evaluated by CMR or CT, with a diagnostic accuracy of 100% based on surgical observation. All CT exams were performed without sedation with a mean dose-length product (DLP32 ) of 29 ± 9 and an effective dose of 1.56 ± 0.6 mSv, range 0.5-2.5 mSv. CMR required general anesthesia in all patients but involved no exposure to ionizing radiation. CT performed better than CMR in assessing tracheal stenosis when compared to TB. It detected complete tracheal cartilage rings in 2/3 patients with PAS, besides tracheomalacia and/or bronchomalacia in 54% of patients.

CONCLUSIONS

Both cross-sectional imaging modalities (CT and CMR) can reliably and accurately diagnose these congenital vascular anomalies. While CT involves exposure to ionizing radiation, it avoids the risks related to anesthesia needed for CMR, and provides a more accurate assessment of tracheobronchial anatomy. TB remains a fundamental tool in tracheomalacia diagnosis in VR symptomatic patients and PAS.

Porcupine Quill Migration in the Thoracic Cavity of a German Shorthaired Pointer

A 7 yr old German shorthaired pointer presented with progressive respiratory distress and lethargy. Two weeks prior to presentation, the dog had porcupine quills removed from the left forepaw, muzzle, and sternal area. At the time of presentation, the dog had bounding pulses and friction rubs in the right dorsal lung field. Harsh lung sounds and decreased lung sounds were ausculted in multiple lung fields. Radiographs revealed a pneumothorax and rounding of the cardiac silhouette suggestive of pericardial effusion. Computed tomographic imaging was performed and revealed multiple porcupine quills in the thoracic cavity. Surgery was performed and quills were found in multiple lung lobes and the heart. Following surgery the dog remained hypotensive. A post-operative echocardiogram revealed multiple curvilinear soft-tissue opacities in the heart. Given the grave prognosis the dog was subsequently euthanized and a postmortem examination was performed. A single porcupine quill was discovered in the left atrium above the mitral valve annulus. The quill extended across the aortic root, impinging on the coronary artery below the level of the aortic valve. To the authors' knowledge, this is the first known report of porcupine quill migration through the heart.

The role of cardiovascular magnetic resonance in pediatric congenital heart disease

Cardiovascular magnetic resonance (CMR) has expanded its role in the diagnosis and management of congenital heart disease (CHD) and acquired heart disease in pediatric patients. Ongoing technological advancements in both data acquisition and data presentation have enabled CMR to be integrated into clinical practice with increasing understanding of the advantages and limitations of the technique by pediatric cardiologists and congenital heart surgeons. Importantly, the combination of exquisite 3D anatomy with physiological data enables CMR to provide a unique perspective for the management of many patients with CHD. Imaging small children with CHD is challenging, and in this article we will review the technical adjustments, imaging protocols and application of CMR in the pediatric population.

Point/counterpoint: dose-related issues in cardiac CT imaging

This manuscript reviews some of the more controversial dose-related issues in cardiac CT imaging. Discussion covers the relative merits of cardiac CT versus MR, advantages and concerns regarding gated versus nongated cardiac CT and advantages and concerns regarding the use of breast shields in girls undergoing cardiac CT imaging.

CMR in Heart Failure

Heart Failure (HF) is a common syndrome with multiple causes. Cardiovascular magnetic resonance (CMR) is a medical imaging technique with significant advantages, allowing the understanding of aetiology and pathophysiology of HF in the individual patient, permitting specific therapy to be administered and predicting prognosis. This paper discusses the diverse role of CMR in HF.

Cross-modality assessment and planning for pulmonary trunk treatment using CT and MRI imaging

Congenital heart defect is the primary cause of death in newborns, due to typically complex malformation of the cardiac system. The pulmonary valve and trunk are often affected and require complex clinical management and in most cases surgical or interventional treatment. While minimal invasive methods are emerging, non-invasive imaging-based assessment tools become crucial components in the clinical setting. For advanced evaluation and therapy planning purposes, cardiac Computed Tomography (CT) and cardiac Magnetic Resonance Imaging (cMRI) are important non-invasive investigation techniques with complementary properties. Although, characterized by high temporal resolution, cMRI does not cover the full motion of the pulmonary trunk. The sparse cMRI data acquired in this context include only one 3D scan of the heart in the end-diastolic phase and two 2D planes (long and short axes) over the whole cardiac cycle. In this paper we present a cross-modality framework for the evaluation of the pulmonary trunk, which combines the advantages of both, cardiac CT and cMRI. A patient-specific model is estimated from both modalities using hierarchical learning-based techniques. The pulmonary trunk model is exploited within a novel dynamic regression-based reconstruction to infer the incomplete cMRI temporal information. Extensive experiments performed on 72 cardiac CT and 74 cMRI sequences demonstrated the average speed of 110 seconds and accuracy of 1.4mm for the proposed approach. To the best of our knowledge this is the first dynamic model of the pulmonary trunk and right ventricle outflow track estimated from sparse 4D cMRI data.

Utility of computed tomographic angiography in the pre-operative planning for initial and repeat congenital cardiovascular surgery

OBJECTIVE

To investigate the utility of computed tomographic angiography as an adjunctive imaging modality before congenital cardiac surgery.

DESIGN

We evaluated 33 patients who underwent a pre-operative computed tomographic angiogram. They were classified according to the anatomic site of repair. Post-operatively, the surgeon completed a questionnaire assessing the utility of the study.

RESULTS

Computed tomographic angiography was found to be either "essential" or "very useful" for pre-operative planning in 94% of the patients. Specifically, the scan was consistently useful for procedures involving the aorta (14/15, 93%) or the pulmonary veins (4/4, 100%) and obviated pre-operative catheterisations in 14 patients (42%). Furthermore, when compared with other diagnostic groups, computed tomographic angiography determined the need for peripheral cannulation in patients undergoing re-operations (6/7; 86%, p = 0.02).

CONCLUSIONS

Computed tomographic angiography was found to be useful in the pre-operative planning of virtually all patients undergoing repair of congenital cardiac malformations, regardless of diagnosis. Specifically, the studies were essential in select populations, such aortic arch or pulmonary vein repairs, and helped to determine cannulation sites for repeat operations while significantly reducing the need for invasive imaging.

Evaluation of myocardial perfusion and function by gated single-photon emission computed tomography technetium-99m methoxyisobutylisonitrile in children and adolescents with severe congenital heart disease

OBJECTIVES

The value of gated single-photon emission computed tomography technetium-99m methoxyisobutylisonitrile (gated SPECT (99m)Tc-MIBI) in children is not yet established probably because gated SPECT (99m)Tc-MIBI has rarely been used in pediatric clinical and research studies. The purpose of this study was to evaluate perfusion abnormalities and left ventricular (LV) function by gated SPECT (99m)Tc-MIBI in children and adolescents with severe congenital heart disease (CHD).

METHODS

Seventeen children and adolescents with severe CHD (11 boys and six girls, mean age 11+/-4 years) underwent 2-day rest-stress (11 boys) or 1-day rest (six girls) gated SPECT (99m)Tc-MIBI. Myocardial perfusion was evaluated by a 17-segment model with a 5-point score to derive the summed stress score, the summed rest score (SRS), and the summed difference score based on the 4D-MSPECT software results. The extent of myocardial perfusion abnormalities was also expressed as a percentage of the LV size. The 4D-MSPECT software was used to calculate LV end-diastolic volume, end-systolic volume (ESV), and ejection fraction (EF).

RESULTS

Reversible myocardial perfusion defect was found in 7 of 11 children (64%) who underwent rest-stress gated SPECT (99m)Tc-MIBI. The LV segments involved were anterior, anteroseptal, anterolateral, apical and inferior. These seven children showed significantly larger perfusion abnormalities on stress compared with rest study (18+/-5 vs. 7+/-4%, P<0.01) and higher summed stress score compared to SRS (11+/-4 vs. 4+/-2, P<0.01). Children and adolescents with myocardial ischemia had significantly lower poststress EF than rest EF (53+/-12 vs. 59+/-11%, P<0.05) and significantly higher poststress ESV than rest ESV (81+/-24 vs. 61+/-25 ml, P<0.05). In six children evaluated only at rest, perfusion defects involved anterior, anteroseptal and apical, or inferolateral segments, accounting for 31+/-12% of LV and with SRS of 12+/-5. Their global LV parameters were: end-diastolic volume 118+/-23 ml, ESV 56+/-16 ml, EF 51+/-10%.

CONCLUSION

Poststress and rest-gated SPECT (99m)Tc-MIBI results indicate that children and adolescents with severe CHD show a range of abnormalities in myocardial perfusion and LV function, which is useful for determining functional importance of morphological malformations. Thus, gated SPECT (99m)Tc-MIBI provides complementary information that may guide clinical decision making in children and adolescents with severe CHD.

Computed tomographic angiography of infants with congenital heart disease receiving extracorporeal membrane oxygenation

Patients with respiratory and/or cardiac failure occasionally require the use of extracorporeal membrane oxygenation (ECMO), which presents an obstacle for standard imaging modalities. Computed tomographic angiography (CTA) can be used in patients with congenital heart disease, usually to define extra-cardiac anatomy in the chest. We describe the use of CTA to evaluate two infants with congenital heart disease while on ECMO. The first infant had totally anomalous pulmonary venous connection, and the second had a pulmonary sling that resulted in tracheal stenosis. The studies achieved high diagnostic quality with minimal radiation exposure. Subsequently, both infants had successful surgical repairs.

The practical clinical value of three-dimensional models of complex congenitally malformed hearts

OBJECTIVE

Detailed 3-dimensional anatomic information is essential when planning strategies of surgical treatment for patients with complex congenitally malformed hearts. Current imaging techniques, however, do not always provide all the necessary anatomic information in a user-friendly fashion. We sought to assess the practical clinical value of realistic 3-dimensional models of complex congenitally malformed hearts.

METHODS

In 11 patients, aged from 0.8 to 27 years, all with complex congenitally malformed hearts, an unequivocal decision regarding the optimum surgical strategy had not been reached when using standard diagnostic tools. Therefore, we constructed 3-dimensional virtual computer and printed cast models of the heart on the basis of high-resolution whole-heart or cine magnetic resonance imaging or computed tomography. Anatomic descriptions were compared with intraoperative findings when surgery was performed.

RESULTS

Independently of age-related factors, images acquired in all patients using magnetic resonance imaging and computed tomography proved to be of sufficient quality for producing the models without major differences in the postprocessing and revealing the anatomy in an unequivocal 3-dimensional context. Examination of the models provided invaluable additional information that supported the surgical decision-making. The anatomy as shown in the models was confirmed during surgery. Biventricular corrective surgery was achieved in 5 patients, palliative surgery was achieved in 3 patients, and lack of suitable surgical options was confirmed in the remaining 3 patients.

CONCLUSION

Realistic 3-dimensional modeling of the heart provides a new means for the assessment of complex intracardiac anatomy. We expect this method to change current diagnostic approaches and facilitate preoperative planning.