Cardiac tomography-echocardiography imaging fusion: a new approach to congenital heart disease.

INTRODUCTION AND OBJECTIVES: Diagnosis, management, and surgical decision-making in children and adults with congenital heart disease are largely based on echocardiography findings. A recent development in cardiac imaging is fusion of different imaging modalities. Our objective was to evaluate the feasibility of computed tomography (CT) and 3-dimensional (3D) transthoracic echocardiography (TTE) fusion in children and adults with congenital heart disease. METHODS: We prospectively included 14 patients, 13 of whom had congenital heart disease, and who underwent both CT and 3D TTE as part of their usual follow-up. We described the steps required to complete the fusion process (alignment, landmarks, and superimposition), navigation, and image evaluation. RESULTS: Median age was 9.5 [2.7-15.7] years, 57% were male, and median body surface area was 0.9 m2 [0.6-1.7]. Congenital heart disease was classified as simple (n=4, 29%), moderate (n=4, 29%), or complex (n=6, 42%). 3D TTE-CT fusion was successful in all patients. Median total time to complete the fusion process was 735 [628-1163] seconds, with no significant difference according to the degree of complexity of the defects. Landmarks were significantly modified in complex congenital heart disease. CONCLUSIONS: We established the feasibility and accuracy of 3D TTE-CT fusion in a population of children and adults with a variety of congenital heart diseases. The simultaneous visualization of many intracardiac structures may help to understand the anatomical features of congenital heart disease without limitations regarding age, weight, or complexity of the congenital defects.

Radiation dose for thoracic and coronary step-and-shoot CT using a 128-slice dual-source machine in infants and small children with congenital heart disease.

BACKGROUND: For coronary artery visualization, retrospective ECG-gated acquisition by dual-source computed tomography (DSCT) was superior to spiral non-ECG-gated acquisition in a paediatric population of congenital heart disease (CHD) patients. However, retrospective cardiac CT is associated with substantial radiation doses to the patient. Recently, DSCT with end-systolic reconstruction was found to be robust for imaging the coronary arteries in patients with high heart rates. OBJECTIVE: To evaluate step-and-shoot DSCT with end-systolic reconstruction for evaluating the heart, coronary arteries and other thoracic structures in young children with CHD. MATERIALS AND METHODS: All neonates and children younger than 6 years of age who were referred to our institution for CHD evaluation between September and October 2009 were included in the study. ECG-gated DSCT was performed in sequential prospective mode centred on the systolic phase identified by ECG analysis. To assess the radiation dose, we recorded the dose-length product (DLP) in mGy·cm and the effective dose in mSv estimated from the DLP. Overall image quality was evaluated using a 5-grade scoring system and was assessed by looking at cardiac and vascular structures. The image quality for the proximal and middle segments of the right and left coronary arteries was also evaluated using a 5-grade scale. RESULTS: Images of diagnostic quality (grade ≥ 3) were obtained in all 30 children with a mean image quality grade of 4.7 ± 0.6 (range, 3-5). Mean DLP was 5.7 ± 4.8 mGy*cm (range, 1-22 mGy cm) and mean effective radiation dose was 0.26 ± 0.16 mSv (range, 0.05-0.8 mSv). CONCLUSION: Prospective ECG-gated thoracic DSCT at end-systole usually provides adequate thoracic and coronary artery image quality in neonates, infants and young children with CHD, independent of heart rate. This new method is associated with lower radiation doses compared to previous literature (mean effective dose, 0.26 mSv).

Robustness of end-systolic reconstructions in coronary dual-source CT angiography for high heart rate patients.

OBJECTIVES: Reconstruction of cardiac computed tomography (CT) images is challenging when the heart rate is higher than 65 beats per minute (bpm). The optimal reconstruction time is often found to be at the end-systolic phase, but image quality remains uncertain. Using dual-source (DS) CT and 83-ms temporal resolution, we evaluated the robustness of the temporal window with low motion during the end systole. METHODS: We studied 41 DSCT in consecutive patients with a heart rate >65 bpm. Eleven systolic reconstructions were performed every 20 ms between 200 ms and 400 ms of the R-R interval. The end-systolic temporal window (ESTW) was defined as the interval between the first and last selected phases judged adequate for diagnosis. RESULTS: Heart rates varied from 67 to 150 bpm. ESTW was always to be found greater than 100 ms. The mean ESTW was 178 ms (SD: 57 ms), and varied independently of heart rate. All data sets achieved diagnostic quality during the end-systolic phase at a time point between 35 and 50% of the R-R interval. CONCLUSION: Our data suggest that CT with a temporal window below 100 ms may provide acceptable systolic reconstructions at any heart rate, in a large proportion of patients.

Multidetector CT for congenital heart patients: what a paediatric radiologist should know.

Multidetector CT (MDCT) is increasingly used for imaging congenital heart disease (CHD) patients in addition to echocardiography, due to its ability to provide high quality three-dimensional images, giving a comprehensive evaluation of complex heart malformations. Using 4-slice or 16-slice CT, diagnostic information in CHD patients is limited to extra-cardiac anatomy, mainly the pulmonary arteries, aorta and venous connections. Due to high heart rates in babies however, coronary evaluation and intra-cardiac analysis were not reliable with the first generations of MDCT. Larger detector size with 64-slice CT and faster acquisition time, up to 75 ms for one slice, has progressively improved coronary and intra-cardiac visualization. Because radiation dose is the main concern, especially in children, every attempt to minimize dose whilst preserving image quality is important: the ALARA concept should always be applied in this population. The 80 kVp setting is now well accepted as a standard for more and more radiological teams involved in CT of children. Different acquisition strategies are now possible for childhood coronary imaging, using retrospective or even prospective gating. Using the latest technology, sub-mSv acquisitions are now attainable for scanning a whole thorax, providing a complete analysis of any 3-D cardiac malformation, including coronary artery course visualisation. This review will describe how technological developments have improved image quality with continuous reduction of radiation dose.

Evaluation of image quality and radiation dose of thoracic and coronary dual-source CT in 110 infants with congenital heart disease.

BACKGROUND: There are only a few reports on the diagnostic accuracy, and the technical and clinical feasibility, of multidetector CT (MDCT) in infants with congenital heart disease (CHD). OBJECTIVE: To evaluate the image quality and radiation dose of DSCT in babies with CHD. MATERIALS AND METHODS: From November 2006 to November 2007, 110 consecutive infants with CHD referred for pre- or postoperative CT evaluation were included. All these infants had a spiral angiothoracic DSCT scan after injection of 300 mg/ml iopromide at 0.5-1 ml/s with a power injector using a low-dose protocol (80 kVp and 10 mAs/kg). Of these infants, 34 also underwent an ECG-gated coronary CT scan for evaluation of the course of the coronary arteries. RESULTS: No serious adverse events were recorded. The mean dose-length product was 8+/-6 mGy x cm (effective dose 0.5+/-0.2 mSv) and 21+/-9 mGy x cm (effective dose 1.3+/-0.6 mSv) during the non-ECG-gated spiral acquisition and ECG-gated acquisition, respectively. Diagnostic quality images were achieved with the spiral acquisition in 89% of cases. Compared to the spiral mode, ECG-gated acquisition significantly improved the visualization of the coronary arteries, with a diagnostic rate of 91% and 84% for the left and right coronary arteries, respectively. CONCLUSION: DSCT together with iopromide at 300 mg/ml is a valuable tool for the routine clinical evaluation of infants with CHD. ECG-gated acquisition provides reliable visualization of the course of the coronary arteries.

Non-invasive diagnosis of ischaemic heart failure using 64-slice computed tomography.

AIMS: We evaluated the accuracy of 64-slice computed tomography (CT) to identify ischaemic aetiology of heart failure (IHF). METHODS AND RESULTS: Ninety-three consecutive patients in sinus rhythm with dilated cardiomyopathy but without suspicion of coronary artery disease (CAD) were enrolled when admitted for angiography. Accuracy of CT to detect significant stenosis (>50% lumen narrowing) was compared with quantitative coronary angiography. IHF was defined as a significant stenosis on left main or proximal left anterior descending artery or two or more vessels. Forty-three out of 1395 segments (3%) were heavily calcified and excluded. CT correctly assessed 103 of 142 (73%) significant stenosis and identified 46 of 50 (92%) patients without and 42 of 43 (98%) patients with CAD, 60 of 62 (97%) patients without and 28 of 31 (90%) patients with IHF. Overall, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT for identifying CAD by segment was 96, 73, 99, 92, and 97%, respectively; by patient was 95, 98, 92, 91, and 98%, respectively; and for identifying IHF was 95, 90, 97, 93, and 95%, respectively. CONCLUSION: Non-invasive 64-slice CT assessment of the extent of CAD may offer a valid alternative to angiography for the diagnosis of IHF.

Coronary microcirculation in acute myocardial ischaemia: From non-invasive to invasive absolute flow assessment.

Although substantial progress has been made in recent decades in reducing mortality and performing optimal revascularization in patients with myocardial infarction, ischaemic heart disease, including acute coronary syndrome, remains the leading cause of mortality worldwide. One of the remaining challenges is to better detect, prevent and treat extended myocardial damage despite angiographically optimal revascularization. Several indices are available in clinical practice to evaluate myocardial damage, infarct size and potential myocardial recovery. These indices are divided into two categories: non-invasive, generally performed after revascularization; and invasive, performed during the revascularization procedure. They allow the clinician to detect patients at risk and may help us to tailor the medical therapy and discharge strategy according to myocardial damage. Because of the number of indices, it is difficult to properly evaluate new therapeutics or to adopt one index that will provide sufficient data to better evaluate and understand the part of the coronary vasculature that is not seen - the microcirculation or so-called "black box". The aim of this review is to describe the non-invasive and invasive indices used to describe the microcirculation and their ability to predict clinical impact, and current dedicated therapeutics that may help to reduce microvascular damage and improve clinical outcomes.

Findings on submillimeter MDCT are predictive of operability in chronic thromboembolic pulmonary hypertension.

OBJECTIVE: The purpose of this study was to investigate whether preoperative 16-MDCT at 0.7-mm collimation can be used to predict the presence of an endarterectomy plane by depicting abnormal thickening of the walls of central pulmonary arteries in patients with chronic thromboembolic pulmonary hypertension. MDCT scans of 40 patients were reviewed retrospectively by two radiologists who were blinded to surgical findings. CONCLUSION: The sensitivity, specificity, and accuracy of MDCT in prediction of the presence of an endarterectomy plane were 99%, 80%, and 96%. Bilateral absence of an endarterectomy plane correlated with postoperative mortality according to Fisher's exact test results (p = 0.004). Submillimeter 16-MDCT therefore may be useful in predicting operability in chronic thromboembolic pulmonary hypertension.

Comparison of coronary minimal lumen area quantification by sixty-four-slice computed tomography versus intravascular ultrasound for intermediate stenosis.

The present study assessed 64-slice computed tomographic accuracy to quantify minimal lumen area (MLA) and determine lesion severity in intermediate stenosis by angiography compared with intravascular ultrasound (IVUS). Sixty-four-slice computed tomography (CT) has been shown to be effective in coronary stenotic assessment by visual estimation compared with angiography. However, angiography is not an accurate gold standard for intermediate stenotic quantification compared with IVUS. Forty patients (54 lesions) with 30% to 70% coronary stenosis by angiography in a major coronary branch were included. All patients underwent quantitative angiography, retrospective electrocardiographically gated 64-slice CT (Siemens), and IVUS (40-MHz Atlantis; Boston Scientific). MLA was manually traced by 2 blinded and independent operators on 64-slice computed tomographic cross-sectional reconstruction and compared with IVUS MLA. A lesion was considered significant if the MLA was

MDCT of the coronary arteries: feasibility of low-dose CT with ECG-pulsed tube current modulation to reduce radiation dose.

OBJECTIVE: The objective of our study was to show the feasibility of coronary CT using low kilovoltage (80 kV) combined with ECG-pulsed tube current modulation in selected patients. CONCLUSION: This study showed the combined effect of lowering the kilovoltage setting (80 kV) and using an automatic modulation technique (ECG-pulsed tube current modulation) for coronary CT. Radiation dose exposure can be reduced by up to 88% for slim patients without impairing image quality.

Preoperative and postoperative evaluation of airways compression in pediatric patients with 3-dimensional multislice computed tomographic scanning: effect on surgical management.

OBJECTIVES: Surgical management of airway compression of vascular origin requires an accurate analysis of anatomy and various mechanisms of compression. This study assessed the usefulness of 3-dimensional computed tomographic scanning in the preoperative and postoperative evaluation of airways compression in a pediatric population. METHODS: Thirty-seven consecutive patients (median age, 4 months) were examined with multislice 3-dimensional computed tomographic scanning: 18 patients before surgical treatment of anomalies of vascular rings, 2 patients because of respiratory symptoms after repair of esophageal atresia, and 17 patients because of persisting respiratory symptoms or prolonged mechanical ventilation after cardiac surgery for congenital heart disease. RESULTS: The procedure was successful, with high-quality diagnostic imaging obtained in all cases without any complications. The anatomy and relationship between the vascular arches and airways was analyzed in all referred patients with vascular arch anomalies confirmed on the basis of the surgical findings, and this helped the surgeon to plan the procedure and choose the best approach. After cardiac surgery, the airway and vascular structures involved and the mechanism of compression were specified in all but one case, and the 3-dimensional computed tomographic scan serves as an important tool for deciding whether to perform reoperation on patients requiring prolonged mechanical ventilation. CONCLUSION: Three-dimensional computed tomographic scanning is a safe, fast, and noninvasive method useful for accurately analyzing the mechanisms of airway compression of vascular origin and thus possible improving the surgical management of pediatric patients.

Characterization of vulnerable nonstenotic plaque with 16-slice computed tomography compared with intravascular ultrasound.

We compared 16-slice computed tomography with intravascular ultrasound in the detection of unstable component characteristics of nonstenotic plaque responsible for acute coronary syndrome. Computed tomography accurately assessed plaque eccentricity, calcification, and remodeling, and intraplaque hypodensity correlated with intravascular ultrasound echolucent area.

Fusión de imágenes de tomografía computarizada cardiaca y ecocardiografía: un nuevo enfoque en las cardiopatías congénitas / Cardiac tomography-echocardiography imaging fusion: a new approach to congenital heart disease

Introducción y objetivos: El diagnóstico y manejo terapéutico de pacientes con cardiopatías congénitas se basa en gran medida en los resultados de la ecocardiografía. Las diferentes técnicas de fusión de imagen han supuesto un reciente avance en la obtención de imágenes cardíacas. Nuestro objetivo ha sido el de evaluar la viabilidad de la fusión de la tomografía computarizada (TC) y la ecocardiografía transtorácica (ETT) 3D en niños y adultos con cardiopatías congénitas. Métodos: Se incluyeron de forma prospectiva 13 pacientes con cardiopatías congénitas y 1 paciente con corazón normal los cuales se sometieron a TC y ETT 3D como parte de su seguimiento habitual. Se describieron los pasos necesarios para completar el proceso de fusión (alineación, puntos de referencia y superposición), la navegación y la evaluación de las imágenes. Resultados: La edad media fue de 9,5 años [2,7-15,7], el 57% eran varones y la superficie corporal media fue de 0,9 m2 [0,6-1,7]. Se clasificaron las cardiopatías como simples (n=4, 29%), moderadas (n=4, 29%) o complejas (n=6, 42%). La fusión 3D ETT-TC fue exitosa en todos los pacientes. La mediana del tiempo total para completar el proceso de fusión fue de 735 segundos [628-1163], sin diferencias significativas según el grado de complejidad de la cardiopatía. Los puntos de referencia se modificaron significativamente en las cardiopatías congénitas complejas. Conclusiones: La técnica de fusión 3D ETT-TC en una población de niños y adultos con diversas cardiopatías congénitas es viable y precisa según demostramos. La visualización simultánea de diferentes estructuras cardíacas podría ayudar a comprender las características anatómicas de las cardiopatías congénitas sin limitaciones en cuanto a la edad, el peso o la complejidad.(AU)

Introduction and objectives: Diagnosis, management, and surgical decision-making in children and adults with congenital heart disease are largely based on echocardiography findings. A recent development in cardiac imaging is fusion of different imaging modalities. Our objective was to evaluate the feasibility of computed tomography (CT) and 3-dimensional (3D) transthoracic echocardiography (TTE) fusion in children and adults with congenital heart disease. Methods: We prospectively included 14 patients, 13 of whom had congenital heart disease, and who underwent both CT and 3D TTE as part of their usual follow-up. We described the steps required to complete the fusion process (alignment, landmarks, and superimposition), navigation, and image evaluation. Results: Median age was 9.5 [2.7-15.7] years, 57% were male, and median body surface area was 0.9 m2 [0.6-1.7]. Congenital heart disease was classified as simple (n=4, 29%), moderate (n=4, 29%), or complex (n=6, 42%). 3D TTE-CT fusion was successful in all patients. Median total time to complete the fusion process was 735 [628-1163] seconds, with no significant difference according to the degree of complexity of the defects. Landmarks were significantly modified in complex congenital heart disease. Conclusions: We established the feasibility and accuracy of 3D TTE-CT fusion in a population of children and adults with a variety of congenital heart diseases. The simultaneous visualization of many intracardiac structures may help to understand the anatomical features of congenital heart disease without limitations regarding age, weight, or complexity of the congenital defects.(AU)

Left pulmonary artery sling with right lung aplasia.

We report 2 cases of right pulmonary aplasia with left pulmonary artery sling responsible for severe respiratory symptoms. Repositioning of the left pulmonary artery without tracheal surgery was successful in both patients. The postoperative course was simple, and the outcome was favorable at last follow-up (after 2 years and 3 months, respectively). Computed tomography provided an accurate diagnostic evaluation that helped to choose the best surgical technique.

Heart transplant patient outcomes: 5-year mean follow-up by coronary computed tomography angiography.

BACKGROUNDS: We evaluate the feasibility and safety of coronary computed tomography angiography (CCTA) as the first-line investigation in heart transplant patients and the rate of coronary allograft vasculopathy detected using CCTA. METHODS: From September 2003 to June 2009, we prospectively included 65 heart transplant recipients, retaining 62 who underwent yearly CCTA for coronary allograft vasculopathy detection (261 CCTAs). We used 16-slice, 64-slice, and 2×64-slice CT machines. Patients with coronary artery stenosis by CCTA had a confirmation and a further follow-up exclusively by conventional coronary angiography (CCA). RESULTS: No major coronary events occurred during the study. Of the 62 baseline CCTAs, 37 (60%) were normal, 18 (29%) showed wall thickening, and 7 (11%) known significant stenosis, confirmed by CCA. The mean follow-up duration was 5 years. At the last follow-up, 26 (70%) patients with normal baseline findings remained normal, 9 (24%) had wall thickening, and 2 (6%) significant stenoses. Time to stenosis was consistently greater than 3 years. Of the 18 patients with initially wall thickening, 14 (78%) had wall thickening and 4 (22%) significant stenosis at last follow-up. The mean interval without any coronary lesion was 9.46±3.98 years. The mean interval without de novo significant stenosis was 10.31±4 years. CONCLUSIONS: CCTA seems to be a safe noninvasive tool for monitoring heart transplant patients, and thus obviating the need for CCA. In patients with normal baseline CCTA, a 2-year interval between CCTAs may be safe.

Diagnostic accuracy of dual-source multislice computed tomographic analysis for the preoperative detection of coronary artery anomalies in 100 patients with tetralogy of Fallot.

OBJECTIVES: A detailed preoperative evaluation of coronary anatomy is mandatory before surgical intervention for tetralogy of Fallot. In pediatric patients, the preoperative evaluation of coronary anatomy has relied classically on conventional angiographic analysis and, more recently, on echocardiographic analysis, which have well-known limitations and complications. Recent technological improvements allow the use of multislice computed tomographic analysis to evaluate coronary artery anatomy in very young children, even those with high heart rates. The purpose of this prospective study was to assess the accuracy of preoperative dual-source computed tomographic analysis in detecting coronary artery abnormalities by using surgical findings as the reference standard. METHODS: We prospectively evaluated 100 patients with tetralogy of Fallot before surgical intervention between November 2006 and September 2009 by using dual-source computed tomographic analysis with either retrospective, electrocardiographically gated, helical computed tomographic analysis or prospective, electrocardiographically triggered, sequential computed tomographic acquisition. The patients had a median age of 6.8 months (range, 1.2 months-6.8 years) and a median weight of 7.9 kg (range, 3-30 kg). RESULTS: Compared with surgical findings, dual-source computed tomographic analysis had 100% sensitivity and 100% specificity for detecting coronary artery abnormalities. Major coronary artery abnormalities were found in 7 (7%) patients. The radiation dose was low. CONCLUSIONS: Dual-source computed tomographic analysis is an accurate and noninvasive tool for delineating coronary artery anatomy before surgical intervention in children with tetralogy of Fallot. Dual-source computed tomographic analysis might deserve to be used routinely instead of angiographic analysis and in combination with echocardiographic analysis for the preoperative assessment of patients with tetralogy of Fallot.

Diagnostic accuracy of multidetector spiral computed tomography for preoperative assessment of sinus venosus atrial septal defects in children.

OBJECTIVES: To prospectively assess the value of multidetector computed tomography (MDCT) for detecting partial anomalous pulmonary venous return (PAPVR) in children with suspected sinus venosus-atrial septal defect (SV-ASD). METHODS: Forty-four children (mean age, 7.3 years; range, nine months-16 years) from whom transthoracic echocardiography (TTE) was inconclusive for the diagnosis underwent MDCT after contrast medium injection. Diagnosis was suspected on TTE by abnormal pulmonary venous return, no visualization of pulmonary venous ostia, or unexpected dilatation of right cavities. The first 11 children also underwent cardiac catheterization. Surgical findings constituted the diagnostic reference standard. RESULTS: Thirty-two (73%) children had SV-ASD with PAPVR. Of the first 11 patients, one had PAPVR by MDCT and 10 by conventional angiography; these 11 patients had PAPVR by surgery. Of the remaining 33 patients, 21 had SV-ASD and 12 had ostium secundum ASD, by both MDCT and surgery. MDCT had 100% sensitivity, 100% specificity, 100% positive predictive value, and 100% negative predictive value for diagnosing PAPVR in patients with suspected SV-ASD. CONCLUSION: Contrast-enhanced MDCT is a highly accurate, minimally-invasive technique for detecting PAPVR associated with SV-ASD. Contrast-enhanced MDCT may be used safely to replace conventional angiography for the definitive diagnosis and preoperative evaluation of children with suspected SV-ASD.

Right aortic arch and isolated left innominate artery from a left sided patent ductus arteriosus: a very rare aortic arch anomaly.

Malformation of the aortic arch system has been described in details by Stewart et al. in 1964. Innominate artery originating via the ductus arteriosus from the pulmonary artery is a very rare type of congenital aortic arch anomaly that has been seldomly reported. We report the case of an aortic arch anomaly revealed by a pulmonary hypertension because of left to right shunt. Surgical procedure was performed through a median sternotomy, without cardiopulmonary bypass. After section. of the ductus arteriosus, the left innominate artery was extensively dissected and mobilized to be implanted on the left side of the ascending aorta under lateral clamping.