Effective radiation dose in computed tomographic angiography of the chest and diagnostic cardiac catheterization in pediatric patients

Pre-operative Imaging of Critical Coarctation of the Aorta: Impact on Surgical Approach and Outcomes

Computed tomographic angiography (CTA) has been increasingly used for the evaluation of infants with aortic arch hypoplasia and coarctation of the aorta. The goals of this study were to compare echocardiographic and CTA findings in critical coarctation of the aorta, to evaluate each modality's influence on surgical approach for repair and determine if pre-operative measurements or surgical approach are associated with residual lesions/re-interventions. This was a single-center retrospective cohort study that included 85 neonates and infants who underwent repair of coarctation/arch hypoplasia by three months of age. Two groups were compared: patients with pre-operative echocardiograms only and patients with both echocardiogram and CTA evaluations. 44 (52%) patients received an echocardiogram and CTA, and 41 (48%) patients received an echocardiogram only. Patients in the CTA + echo group had smaller mitral valve and ascending aorta measurements (p = 0.01). When comparing CTA to echocardiogram measurements, the aortic valve annulus, ascending aorta, proximal and distal transverse arch, and isthmus were smaller on echo (p < 0.01). A smaller aortic valve annulus and aortic root as well as thoracotomy approach were associated with residual gradients/re-intervention (p < 0.01). Our study found that patients who underwent CTA preoperatively had smaller left-sided structures. Aortic measurements were smaller on echocardiogram when compared to CTA. Smaller left-sided structures proximal to the aortic arch and thoracotomy predicted the development of residual lesions/re-intervention. CTA is useful in the surgical planning for neonates with arch hypoplasia/coarctation and may help risk stratify for residual lesions/re-intervention.

Cumulative Radiation Dose from Medical Imaging in Children with Congenital Heart Disease: A Systematic Review

Children with congenital heart disease are exposed to repeated medical imaging throughout their lifetime. Although the imaging contributes to their care and treatment, exposure to ionising radiation is known to increase one's lifetime attributable risk of malignancy. A systematic search of multiple databases was performed. Inclusion and exclusion criteria were applied to all relevant papers and seven were deemed acceptable for quality assessment and risk of bias assessment. The cumulative effective dose (CED) varied widely across the patient cohorts, ranging from 0.96 mSv to 53.5 mSv. However, it was evident across many of the included studies that a significant number of patients were exposed to a CED >20 mSv, the current annual occupational exposure limit. Many factors affected the dose which patients received, including age and clinical demographics. The imaging modality which contributed the most radiation dose to patients was cardiology interventional procedures. Paediatric patients with congenital heart disease are at an increased risk of receiving an elevated cumulative radiation dose across their lifetime. Further research should focus on identifying risk factors for receiving higher radiation doses, keeping track of doses, and dose optimisation where possible.

The Utility of CT Angiography in Neonates with Pulmonary Atresia with Intact Ventricular Septum and Concern for Right Ventricular Dependent Coronary Circulation: Case Series

Up to one third of patients with pulmonary atresia with intact ventricular septum (PA-IVS) will have inadequate anterograde coronary blood flow and rely on fistulous connections from the right ventricle (RV) for myocardial perfusion, known as RV-dependent coronary circulation (RVDCC). Historically, identification of the extent of ventriculocoronary connections and coronary stenosis has required invasive imaging with cardiac catheterization and angiography. Cardiac computed tomography (CCT) potentially provides a less invasive imaging option for therapeutic planning in this group of patients. We describe six neonates with PA-IVS who underwent both CCT and cardiac catheterization at our institution prior to any surgical or transcatheter intervention between 2009 and 2019. Imaging was concerning for RVDCC in all six patients. The average tricuspid Z-score was - 4.19 (2.1 to - 5.34). Two patients underwent cardiac transplantation and two patients underwent ductal stenting. The overall mortality rate was 50%. CCT findings closely mirrored the findings of invasive cardiac catheterization and identified important morphological variations. The average radiation exposure (DLP) per CCT was (10.5 mGy cm, range 6-20). Technological improvements in CCT have enabled adequate visualization of coronary anomalies in children with comparable accuracy to cardiac catheterization, but considerably less radiation exposure. However, diagnosis of RVDCC requires direct right ventricular angiography. Therefore, the potential benefit of obtaining a CCT prior to catheterization for infants with PA-IVS is the ability to risk stratify, assist with procedural planning, and improve family counseling.

Prematurity and Congenital Heart Disease: A Contemporary Review

Congenital heart disease (CHD) is the most commonly reported birth defect in newborns. Neonates with CHD are more likely to be born prematurely, and a higher proportion of preterm neonates have CHD than their term counterparts. The implications of preterm birth on the cardiac and noncardiac organ systems are vast and require special management considerations. The feasibility of surgical interventions in preterm neonates is frequently limited by patient size and delicacy of immature cardiac tissues. Thus, special care must be taken when considering the appropriate timing and type of cardiac intervention. Despite improvements in neonatal cardiac surgical outcomes, preterm and early term gestational ages and low birthweight remain important risk factors for in-hospital mortality. Understanding the risks of early delivery of neonates with prenatally diagnosed CHD may help guide perioperative management in neonates who are born preterm. In this review, we will describe the risks and benefits of early delivery, postnatal cardiac and noncardiac evaluation and management, surgical considerations, overall outcomes, and future directions regarding optimization of perinatal evaluation and management of fetuses and preterm and early term neonates with CHD.

Variation in Advanced Diagnostic Imaging Practice Patterns and Associated Risks Prior to Superior Cavopulmonary Connection: A Multicenter Analysis

Single ventricle patients typically undergo some form of advanced diagnostic imaging prior to superior cavopulmonary connection (SCPC). We sought to evaluate variability of diagnostic practice and associated comprehensive risk. A retrospective evaluation across 4 institutions was performed (1/1/2010-9/30/2016) comparing the primary modalities of cardiac catheterization (CC), cardiac magnetic resonance (CMR), and cardiac computed tomography (CT). Associated risks included anesthesia/sedation, vascular access, total room time, contrast agent usage, radiation exposure, and adverse events (AEs). Of 617 patients undergoing SCPC, 409 (66%) underwent at least one advanced diagnostic imaging study in the 60 days prior to surgery. Seventy-eight of these patients (13%) were analyzed separately because of a concomitant cardiac intervention during CC. Of 331 (54%) with advanced imaging and without catheterization intervention, diagnostic CC was most common (59%), followed by CT (27%) and CMR (14%). Primary modality varied significantly by institution (p < 0.001). Median time between imaging and SCPC was 13 days (IQR 3-33). Anesthesia/sedation varied significantly (p < 0.001). Pre-procedural vascular access did not vary significantly across modalities (p = 0.111); procedural access varied between CMR/CT and CC, in which central access was used in all procedures. Effective radiation dose was significantly higher for CC than CT (p < 0.001). AE rate varied significantly, with 12% CC, 6% CMR, and 1% CT (p = 0.004). There is significant practice variability in the use of advanced diagnostic imaging prior to SCPC, with important differences in associated procedural risk. Future studies to identify differences in diagnostic accuracy and long-term outcomes are warranted to optimize diagnostic protocols.

Acquired anomalies of the coronary arteries after arterial switch operation. Usefulness of coronary computed tomography angiography and impact on follow-up

INTRODUCTION

Mortality and morbidity in patients with transposition of the great arteries after an arterial switch operation depends mainly on the status of coronary perfusion. Coronary computed tomography angiography (CCTA) provides accurate information on coronary morphology, however its use in these patients is not yet routine procedure.

OBJECTIVE

We sought to assess its accuracy to identify acquired coronary anomalies in this population, compared to conventional angiography in a subset of patients, and assess its impact on postoperative management.

METHODS

Retrospective analysis of clinical data on transposition of the great arteries in patients who underwent CCTA between January 2013 and September 2017.

RESULTS

Between January 2013 and September 2017, 18 patients underwent CCTA. Seven patients (39%) disclosed iatrogenic coronary lesions (stenosis 1; kinking 2, occlusion 1; filiform coronary 3). The exam was performed in 78% of patients due to suggestion of myocardial ischemia (symptoms or altered exams). Only 16% needed to undergo additional exams, and in four patients the CCTA result modified therapeutic management. Conventional coronary angiography was also performed in 10 patients (55%), and in three cases, the results were discordant with underestimation or non-identification of coronary lesions on conventional angiography. The medium radiation dose used was 2.4 mSv and no complications after CT were reported.

CONCLUSION

CCTA accurately identified iatrogenic postoperative coronary lesions and it has proven to be superior to conventional angiography in this population. It should be performed routinely in this group of patients, even in the absence of symptoms.

Multi-institution Assessment of the Accuracy of Cardiac Computed Tomography in Preparation for Superior Cavopulmonary Connection

BACKGROUND

Patients with single ventricle (SV) congenital heart disease (CHD) undergo several interventions in the first years of life. Advanced diagnostics are required for interstage assessment of anatomy, but are associated with significant diagnostic risk. We sought to evaluate image quality, risk, and accuracy of cardiac computed tomography (CCT) for evaluation of anatomy prior to superior cavopulmonary connection (SCPC) compared to surgical findings across 2 institutions.

METHODS

A retrospective evaluation of image quality, risk, and accuracy of pre-SCPC CCT was performed at 2 institutions between January 1, 2010 and September 30, 2016.

RESULTS

CCT was performed in 90 SV CHD patients with a median age of 4.03 months (interquartile range [IQR] 3.36, 5.33) prior to SCPC. Image quality was optimal (84%) or good (16%) in all patients, without significant discrepancy compared to surgical findings. 7 patients (8%) required interventional cardiac catheterization subsequent to CCT and before surgical intervention. 49% of scans were performed without sedation, 43% of scans were performed with mild to moderate sedation, and 8% of scans were performed with general anesthesia. The median total procedural dose-length product (DLP) was 18 (IQR 14, 26) mGy*cm, estimating an age adjusted radiation dose of 1.4 millisievert (mSv). One minor (1%) adverse event was reported within 24 h of the CCT. Surgical complications were unrelated to the presurgical findings.

CONCLUSIONS

CCT for pre-SCPC evaluation is safe, with excellent accuracy for anatomy at the time of surgical intervention across 2 institutions. In select patients, noninvasive evaluation with CCT may be indicated.

Acquired anomalies of the coronary arteries after arterial switch operation. Usefulness of coronary computed tomography angiography and impact on follow-up

INTRODUCTION

Mortality and morbidity in patients with transposition of the great arteries after an arterial switch operation depends mainly on the status of coronary perfusion. Coronary computed tomography angiography (CCTA) provides accurate information on coronary morphology, however its use in these patients is not yet routine procedure.

OBJECTIVE

We sought to assess its accuracy to identify acquired coronary anomalies in this population, compared to conventional angiography in a subset of patients, and assess its impact on postoperative management.

METHODS

Retrospective analysis of clinical data on transposition of the great arteries in patients who underwent CCTA between January 2013 and September 2017.

RESULTS

Between January 2013 and September 2017, 18 patients underwent CCTA. Seven patients (39%) disclosed iatrogenic coronary lesions (stenosis 1; kinking 2, occlusion 1; filiform coronary 3). The exam was performed in 78% of patients due to suggestion of myocardial ischemia (symptoms or altered exams). Only 16% needed to undergo additional exams, and in four patients the CCTA result modified therapeutic management. Conventional coronary angiography was also performed in 10 patients (55%), and in three cases, the results were discordant with underestimation or non-identification of coronary lesions on conventional angiography. The medium radiation dose used was 2.4 mSv and no complications after CT were reported.

CONCLUSION

CCTA accurately identified iatrogenic postoperative coronary lesions and it has proven to be superior to conventional angiography in this population. It should be performed routinely in this group of patients, even in the absence of symptoms.

Sensitivity of High-Pitch Dual-Source Computed Tomography for the Detection of Anomalous Pulmonary Venous Connection in Infants

PURPOSE

 To evaluate the sensitivity, specificity, and interobserver reliability of high-pitch dual-source computed tomography angiography (CTA) in the detection of anomalous pulmonary venous connection (APVC) in infants with congenital heart defects and to assess the associated radiation exposure.

MATERIALS AND METHODS

 78 pulmonary veins in 17 consecutively enrolled patients with congenital heart defects (6 females; 11 males; median age: 6 days; range: 1-299 days) were retrospectively included in this study. All patients underwent high-pitch dual-source CTA of the chest at low tube voltages (70 kV). APVC was evaluated independently by two radiologists. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and interobserver agreement were determined. For standard of reference, one additional observer reviewed CT scans, echocardiography reports, clinical reports as well as surgical reports. In cases of disagreement the additional observer made the final decision based on all available information.

RESULTS

 Detection of APVC with high-pitch dual-source CTA revealed a good sensitivity (91 %) and specificity (99 %), with PPV and NPV of 98 % and 97 %. Interobserver agreement was almost perfect (Kappa = 0.84). The median DLP was 3.8 mGy*cm (IQR 3.3-4.7 mGy*cm) and the median radiation dose was 0.33 mSv (IQR 0.26-0.39 mSv).

CONCLUSION

 High-pitch dual-source CTA in infants with congenital heart defects allows for accurate and reliable assessment of APVC at a low radiation dose.

KEY POINTS

  · High-pitch dual-source CTA enables detection of anomalous pulmonary vein connection with high sensitivity in infants.. · Interrater reliability in the detection of anomalous pulmonary vein connection with high-pitch dual-source CTA is almost perfect.. · Radiation dose of high-pitch dual-source CTA in the cardiac examination of infants is low..

CITATION FORMAT

· Well L, Weinrich JM, Meyer M et al. Sensitivity of High-Pitch Dual-Source Computed Tomography for the Detection of Anomalous Pulmonary Venous Connection in Infants. Fortschr Röntgenstr 2021; 193: 551 - 558.

Cardiac CT in the Preoperative Diagnostics of Neonates with Congenital Heart Disease: Radiation Dose Optimization by Omitting Test Bolus or Bolus Tracking

RATIONALE AND OBJECTIVES

Congenital heart diseases (CHD) belong to the leading causes of infant mortality worldwide. Prognostic improvements result from multimodal therapy strategies leading to an increased demand for noninvasive imaging. The aim of the study was to further optimize cardiac CT radiation dose by omitting the test bolus or bolus tracking scan, which can have a relevant share of radiation exposure, especially in neonates.

MATERIALS AND METHODS

This retrospective study included 25 neonates with CHD who received a CT angiography (CTA) from 2009 to 2018. The examinations were performed as a high-pitch CTA (pitch 3.4, 80 kV) with manual contrast administration (1.5 ml/kg body weight) and fixed scan delay depending on the respective heart defect. Diagnosis, adverse events, radiation dose parameters, objective (contrast-to-noise ratio) and subjective (4-point Likert scale) image quality as well as diagnostic accuracy compared to intraoperative findings was assessed.

RESULTS

All examinations were diagnostically evaluable without adverse events. The median CT dose index volume (CTDI_vol) was 0.50 mGy (range, 0.15-0.94), the median dose-length product was 8 mGy × cm (range, 3-17). The estimation of the effective dose by Monte Carlo simulation revealed lower median dose levels 0.66 mSv (range, 0.25-1.40 mSv) than previously published in comparable groups. All examinations achieved a very good mean image quality score of 1.2 ± 0.4 with only minimal image noise and mean contrast-to-noise ratio of 16.1 ± 7.0. Diagnostic accuracy was 100 % as cardiac anatomy revealed no new diagnoses or significant differences in the subsequent cardiac surgery.

CONCLUSION

Cardiac high-pitch CTA of neonates with CHD can be performed safely and dose-reducing without additional test bolus or bolus tracking scan. With very good image quality, it provides a detailed insight into the cardiac anatomy and thus enables a differentiated, noninvasive therapy planning.

Comparison of computed tomography angiography versus cardiac catheterization for preoperative evaluation of major aortopulmonary collateral arteries in pulmonary atresia with ventricular septal defect

Introduction:

Pulmonary atresia with the ventricular septal defect is a rare congenital heart defect with high anatomic variability. The most important management question relates to the sources of pulmonary blood flow. The ability to differentiate between ductal dependence and major aortopulmonary collateral arteries is critical to achieving good outcomes and avoiding life-threatening hypoxia in the postneonatal period. Having accurate information about pulmonary arteries, major aortopulmonary collateral arteries, and sources of blood supply to each pulmonary segment is crucial for choosing the optimal surgical strategy. The purpose of this study is to compare computed tomography angiography (CTA) with cardiac catheterization for anatomic delineation of surgically relevant anatomy in pulmonary atresia with ventricular septal defect with major aortopulmonary collateral arteries.

Materials and Methods:

Retrospective review of all children with pulmonary atresia with ventricular septal defect with major aortopulmonary collateral arteries cared for at a large tertiary children's hospital who underwent cardiac catheterization with angiography and CTA close to each other without interval therapy. All studies were performed between 2007 and 2011.

Results:

There were 9 patients who met the inclusion criteria. Pulmonary artery anatomy (confluent vs. nonconfluent) was correctly identified in 9 patients by CTA and 8 patients by catheterization. There were no significant differences between CTA and catheterization in the identification of major aortopulmonary collateral arteries (mean = 3.4 collaterals/study via catheterization; mean = 3.1 collaterals/study via CTA; P = 0.67). CTA was superior to catheterization in the delineation of segmental pulmonary blood flow (P = 0.006).

Conclusion:

CTA and catheterization are equivalent in their ability to delineate pulmonary artery anatomy and major aortopulmonary collateral arteries.

Preprocedural three-dimensional planning aids in transcatheter ductal stent placement: A single-center experience

OBJECTIVES

Describe the use of three-dimensional (3D) patent ductus arteriosus (PDA) modeling to better define ductal anatomy to improve preprocedural planning for ductal stent placement.

BACKGROUND

Ductal stenting is an alternative to surgical shunting in patients with ductal dependent pulmonary blood flow. Ductal anatomy is often complex with extreme tortuosity and risk of pulmonary artery isolation, thus increasing procedural risks.

METHODS

CT angiograms were segmented to produce 3D PDA models. Ductal morphology was characterized with attention to access approach, degree of pulmonary artery offset/risk of isolation and ductal tortuosity. 3D models were retrospectively compared with biplane angiography.

RESULTS

3D modeling was performed in 12 patients with adequate image quality for complete analysis in 11; median (interquartile range) age/weight 17 days (8-20 days) and 3.1 kg (2.4-3.9 kg). The PDA was reverse oriented in nine with average length of 17.2 ± 2.5 mm and high tortuosity (mean tortuosity index 52, range 3-108). From 3D modeling, two patients were excluded from ductal stenting-extreme ductal tortuosity and threatened pulmonary artery discontinuity, respectively. Ductal stenting was successful in the remaining nine with no major procedural complications. 3D modeling predicted a successful access approach based on the aortic orientation of the ductus in all patients (five carotid, two axillary, two femoral). When comparing 2D angiography with 3D models, angiography consistently underestimated ductal length (-3.2 mm ± 1.6 mm) and tortuosity (-14.8 ± 7.2).

CONCLUSIONS

3D modeling prior to ductal stent placement for ductal dependent pulmonary blood flow is useful in procedural planning, specifically for eligibility, access approach, and accurate ductal measurements. Further studies are needed to determine if 3D planning improves procedural outcomes.

Can we predict potentially dangerous coronary patterns in patients with transposition of the great arteries after an arterial switch operation?

INTRODUCTION

Coronary artery complications are the main reason for early mortality after an arterial switch operation. Late complications are relatively rare, and there is no consensus regarding the need or indications for routine follow-up coronary artery evaluations or the best first-line assessment modality. The aim of this study was to present the long-term post-operative frequency of coronary abnormalities in asymptomatic patients with transposition of the great arteries discovered by coronary CT angiography and potential "red flags" revealed by other examinations.

PATIENTS AND METHODS

A group of 50 consecutive asymptomatic patients who underwent routine long-term coronary artery evaluation after an arterial switch operation according to our institutional protocol were qualified for this study. This routine in-hospital visit included a detailed medical interview, electrocardiography, echocardiography, Holter electrocardiography examinations, and laboratory and cardiopulmonary exercise tests. Patients who showed significant abnormalities were qualified for perfusion scintigraphy.

RESULTS

Unfavourable coronary abnormalities were detected in 30 patients (60%) and included ostial stenosis, muscular bridge, coronary fistula, interarterial course, proximal kinking, high ellipticity index, proximal acute angulation (<30 degree) of the left coronary artery, and proximal acute angulation of the right coronary artery. These features could not be predicted based on the medical interviews, surgical reports, or non-invasive screening test results.

CONCLUSION

Complex coronary configurations with potentially dangerous coronary features are common in patients with transposition after an arterial switch operation. Such high-risk patients cannot be identified indirectly, and coronary CT angiography provides accurate information that is useful for post-operative management.

Organ and effective doses detriment to paediatric patients undergoing multiple interventional cardiology procedures

The aims of the present study were to present the frequency of multiple interventional cardiac procedures for a certain group of patients obtained at one of the largest paediatric hospitals in Chile. In addition it has been analysed cumulative kerma area product (KAP) and cumulative air kerma (CAK), and calculated organ doses for the patient groups undergoing 2, 3 and ≥ 4 procedures, using Monte Carlo software. Effective doses were also estimated for epidemiological purposes and to permit comparison with other imaging procedures. The sample used corresponds to the last 9 years and refers to a total of 1521 paediatric patients and 1824 interventional cardiac procedures. The results for frequency were: 13.7% of patients underwent 2 procedures, 4.1% underwent 3 procedures and 1.4% underwent 4 or more procedures. The median KAP and CAK values measured for the cumulative procedures in these three groups of patients were 3.7, 5.4 and 10.8 Gy·cm² and 59.9, 83.2 and 147.6 mGy, respectively. In terms of the most irradiated organs during interventional cardiac procedures, the highest median values (for the group of ≥4 procedures) were: active bone marrow 5.0 mGy, lungs 23.5 mGy, oesophagus 15.2 mGy, thyroid 7.8 mGy and breast 11.0 mGy. Median dose value to the heart (for the group of ≥4 procedures) was 12.7 mGy. Median values in terms of calculated effective dose for the three patient groups (with 2, 3 and ≥4 procedures) were 3.4, 5.9 and 8.7 mSv, respectively.

Dramatic Dose Reduction in Three-Dimensional Rotational Angiography After Implementation of a Simple Dose Reduction Protocol

Previously, median effective dose (ED) of 1.6 mSv per three-dimensional rotational angiography (3DRA) has been reported. This study evaluated ED and image quality in 3DRA after implementation of a simple dose reduction protocol in pediatric catheterizations. Simple conversion factors between 3DRA ED and readily available parameters at the cathlab were determined. The dose reduction protocol consisted of frame reduction (60-30 frames/s (f/s)), active collimation of the X-ray beam, usage of a readily available low dosage program, and a pre-3DRA run check. EDs were calculated with Monte Carlo PCXMC 2.0. Three observers blindly assessed 3DRA image quality of the dose reduction and normal-dose cohort. Between October 2014 and October 2015, 84 patients (median age 4.3 years) underwent 100 3DRAs with a median ED of 0.54 mSv (0.12-2.2) using the dose reduction protocol. Median ED in the normal-dose cohort (17 3DRAs) was 1.6 mSv (1.2-4.9). Image quality in the dose reduction cohort remained excellent. Correlations between ED and dose area product (DAP) and ED and skin dose were found with a ρ of 0.82 and 0.83, respectively. ED exposure of the entire catheterization was reduced to 2.64 mSv. Introduction of a simple protocol led to 66% dose reduction in 3DRA and 79% in the entire catheterization. 3DRA image quality in this group remained excellent. In 3DRA ED correlates well with DAP and skin dose, parameters readily available at the cathlab.

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.

Diagnostic accuracy of low-dose dual-source cardiac computed tomography as compared to surgery in univentricular heart patients

BACKGROUND

To evaluate the ability of low radiation dose dual-source computed tomography (DSCT) to depict the features of morphological univentricular heart and to define accuracy by comparing findings with surgery.

METHODS

Low radiation dose dual-source cardiac computed tomography (CCT) of 33 cases of functional univentricular heart preliminary diagnosis by echocardiography compared with the results of surgery were retrospectively analyzed (aged 1 day to 4 years, median 5 months). The appropriate dose reduction strategies and iterative reconstruction were applied.

RESULTS

Thirty three univentricular heart patients were classified into three types according to Anderson's classification method, including 16 cases (48.5%) univentricular of right ventricular type with rudimentary chamber of left ventricle, 11 cases (33.3%) univentricular of left ventricular type with rudimentary chamber of right ventricle and 6 cases (18.2%) univentricular heart of indeterminate type without rudimentary chamber. The extracardiac malformation such as hypoplastic aortic arch, coronary artery fistula, total anomalous pulmonary venous returns or hypoplastic lung were presented frequently. The overall sensitivity and specification of cardiac CT was 100% compared to the results of surgery. The procedural dose-length product was 18 ± 5 mGy-cm, and unadjusted and adjusted radiation doses were 0.25 and 0.64 mSv, respectively.

CONCLUSION

Cardiac CT can diagnose accurately and be performed with a low radiation exposure in patients with the functional univentricular heart disease. The aorta, pulmonary artery and lung can be evaluated completely and simultaneously as well. Cardiac CT is an effective advanced non-invasive imaging modality to comprehensive evaluation the functional univentricular heart patients, particularly if cardiac MRI poses a high risk or is contraindicated.

Cardiovascular CT for evaluation of single-ventricle heart disease: risks and accuracy compared with interventional findings

OBJECTIVE

We sought to evaluate the risk and image quality from cardiovascular CT in patients across all stages of single-ventricle palliation, and to define accuracy by comparing findings with intervention and surgery.

METHODS

Consecutive CT scans performed in patients with single-ventricle heart disease were retrospectively reviewed at a single institution. Diagnosis, sedation needs, estimated radiation dose, and adverse events were recorded. Anatomical findings, image quality (1-4, 1=optimal), and discrepancy compared with interventional findings were determined. Results are described as medians with their 25th and 75th percentiles.

RESULTS

From January, 2010 to August, 2015, 132 CT scans were performed in single-ventricle patients of whom 20 were neonates, 52 were post-Norwood, 15 were post-Glenn, and 45 were post-Fontan. No sedation was used in 76 patients, 47 were under minimal or moderate sedation, and nine were under general anaesthesia. The median image quality score was 1.2. The procedural dose-length product was 24 mGy-cm, and unadjusted and adjusted radiation doses were 0.34 (0.2, 1.8) and 0.82 (0.55, 1.88) mSv, respectively. There was one adverse event. No major and two minor discrepancies were noted at the time of 79 surgical and 10 catheter-based interventions.

CONCLUSIONS

Cardiovascular CT can be performed with a low radiation exposure in patients with single-ventricle heart disease. Its accuracy compared with that of interventional findings is excellent. CT is an effective advanced imaging modality when a non-invasive pathway is desired, particularly if cardiac MRI poses a high risk or is contraindicated.

Usefulness of Routine Coronary CT Angiography in Patients with Transposition of the Great Arteries After an Arterial Switch Operation

Coronary complications in patients with transposition of the great arteries (TGA) after an arterial switch operation (ASO) are relatively rare, but of all the possible postoperative adverse events, they are potentially the most dangerous. The fate of the coronary arteries, which are transplanted during the neonatal ASO, remains uncertain. There is also no consensus regarding their postoperative evaluation, especially in asymptomatic patients. The aim of this study was to present the early results of routinely performed coronary computed tomography angiography (CCTA) in asymptomatic adolescents and young adults with TGA after an ASO. An initial series of 50 CCTAs performed in asymptomatic patients with TGA after an ASO were evaluated. In each case, a detailed examination of the coronary anatomy, its relationship to the surrounding structures, its exact position in the neoaortic sinus, and the presence of significant coronary abnormalities was performed. The CT scans revealed significant coronary abnormalities in 12 asymptomatic patients: three had acute proximal angulation and stenosis, four had an intra-arterial course, seven had a muscular bridge, one had a left anterior descending artery with an intramuscular course, and one had coronary fistulas to the pulmonary arteries. Additionally, in 25 patients, proximal acute angulation of at least one coronary artery was detected, and four of them had a high ellipticity index. Most of the potentially severe anatomical features were related to the left coronary artery or the left anterior descending artery. CCTA routinely performed on asymptomatic patients with TGA after an ASO provides accurate and useful information for postoperative management. The frequency of coronary anomalies and potentially dangerous anatomical features in this group of patients is high, and their impact on postoperative follow-up remains unknown.

Reduction in Radiation Dose in a Pediatric Cardiac Catheterization Lab Using the Philips AlluraClarity X-ray System

The objective of this study was to compare radiation doses and imaging quality using Philips AlluraClarity (Philips Healthcare, Best, The Netherlands) X-ray system and an older generation reference system. AlluraClarity is a new generation fluoroscopy system designed to reduce radiation without compromising image quality, but reports of its use in pediatric patients are limited. Dose area products (DAP, mGy cm²) and DAP/kg were compared in patients catheterized using Allura Xper and AlluraClarity systems over a year of use for each. Randomly selected studies from each system were assessed for image quality. The 430 patients imaged with Clarity were larger than the 332 imaged with Xper (median BSA: 0.74 vs. 0.64 m², p = 0.06), and median total fluoroscopic times (TFT) were similar (15.8 vs. 16.1 min, p = 0.37). Median DAPs were 8661 mGy cm² (IQR: 18,300 mGy cm²) and 4523 mGy cm² (IQR: 11,596 mGy cm²) with Xper and Clarity, respectively (p < 0.001). There was a reduction in median DAP in all procedure categories. After adjustment for BSA, TFT, and procedure type, using Clarity was associated with a 57.5% (95% CI 51.5-62.8%, p < 0.001) reduction in DAP for all procedures. Reductions did not significantly differ by weight (<10 kg, 10-40 kg, ≥ 40 kg). There was an adjusted percent reduction in DAP for each procedure category ranging from 39.0% (95% CI 25.6-50.1%, p < 0.001) for cardiac biopsies with or without coronary angiography to 67.6% (95% CI 61.2-72.8%, p < 0.001) for device occlusions. Mean overall imaging quality scores (4.3 ± 0.8 with Clarity vs. 4.4 ± 0.6 with Xper, p = 0.62) and scores based on specific quality parameters were similar in the two groups. Use of AlluraClarity substantially reduced radiation doses compared to the older generation reference system without compromising imaging quality in a pediatric cardiac catheterization lab.

Unknown vascular compression of the airway in patients with congenitalheart disease and persistent lower respiratory symptoms

Background/aim: Airway compression (AC) by vascular structures is an important complication of congenital heart disease (CHD) that often goes unrecognized. It is not easy to identify whether CHD patients require additional invasive examinations or not. Therefore, the present study aims to develop an AC diagnostic algorithm for CHD patients. Materials and methods: CHD patients with persistent respiratory symptoms that were treated between January 2007 and December 2015 were retrospectively reviewed. The following data were recorded for all CHD patients with AC: age, cardiac anomalies, the compressed structure, the airway diameter ratio (ADR), the compressing structure(s), treatment, and follow-up.Results: During the 8-year study period, 62 of 253 CHD patients had persistent respiratory symptoms, of which 11 cases were diagnosed as AC via bronchoscopy and/or thoracic computed tomography angiography. The most frequently affected structures were the left main bronchus and trachea, and the most common compressing structure was the right pulmonary artery. The ADR was near total compression in 3 patients and >0.50 in 3 patients. During follow-up, 5 of the 11 patients with AC underwent surgery, 2 died, and 4 were followed clinically. Patients with ADR of >0.50 did not require surgery and were followed clinically. Conclusion: CHD patients with persistent respiratory symptoms associated with lower respiratory airway obstruction should be evaluated via invasive examination. An AC diagnostic algorithm for pediatric CHD patients was developed.

Low-Dose Computed Tomographic Imaging of Partial Anomalous Pulmonary Venous Connection in Children

Background:

In this study, we aimed to determine lobar distribution, drainage sites, and associated cardiovascular anomalies of partial anomalous pulmonary venous connection in pediatric patients using low-dose multidetector computed tomographic angiography.

Methods:

Sixty-one cases (27 female, mean age: 4.7 years) with partial anomalous pulmonary venous connection diagnosed by multidetector computed tomographic angiography were included in this study. In all patients, multidetector computed tomographic angiography examinations were performed using dual-source 256-slice scanner without sedation.

Results:

In 61 patients, 73 anomalous pulmonary veins were detected, 56 (77%) of them were right-sided and 17 (23%) were left-sided. Of 56 right-sided anomalous pulmonary veins in 49 patients, 38 (68%) drained into superior vena cava, eight (14%) into atriocaval junction, six (11%) into inferior vena cava, three (5%) into right atrium, and one (2%) into levoatriocardinal vein. Of 17 left-sided anomalous pulmonary veins in 12 patients, 16 (94%) drained into left innominate vein, and one (6%) into coronary sinus. Only seven (12%) patients had isolated partial anomalous pulmonary venous connection, whereas 54 (88%) patients had additional cardiovascular anomalies. The most common (66%) associated anomaly is atrial septal defect. The overall mean effective radiation dose was 1.12 mSv (range: 0.15-7.41 mSv), and it was 0.58 mSv (range: 0.15-0.73) in the patients younger than one-year old.

Conclusions:

The presence and course of the anomalous pulmonary veins and associated cardiovascular anomalies can be reliably detected by dual-source 256-slice multidetector computed tomographic angiography with low radiation doses.

Radiation Safety in Children With Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization From the Image Gently Alliance

There is a need for consensus recommendations for ionizing radiation dose optimization during multimodality medical imaging in children with congenital and acquired heart disease (CAHD). These children often have complex diseases and may be exposed to a relatively high cumulative burden of ionizing radiation from medical imaging procedures, including cardiac computed tomography, nuclear cardiology studies, and fluoroscopically guided diagnostic and interventional catheterization and electrophysiology procedures. Although these imaging procedures are all essential to the care of children with CAHD and have contributed to meaningfully improved outcomes in these patients, exposure to ionizing radiation is associated with potential risks, including an increased lifetime attributable risk of cancer. The goal of these recommendations is to encourage informed imaging to achieve appropriate study quality at the lowest achievable dose. Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making and programmatic approaches to ensure appropriate dose monitoring. Looking ahead, there is a need for standardization of dose metrics across imaging modalities, so as to encourage comparative effectiveness studies across the spectrum of CAHD in children.

The utility of computed tomographic angiography in a neonate on extracorporeal membrane oxygenation with extreme cyanosis after Blalock-Taussig shunt

A modified Blalock-Taussig shunt (mBTS) is often employed to provide pulmonary blood flow in neonates that are born with cyanotic congenital heart defects. However, acute shunt thrombosis can occur in the postoperative period, resulting in profound cyanosis. In this case report, we describe the utility of computed tomographic angiography (CTA) in the management of a neonate with extreme cyanosis after placement of a mBTS while on extracorporeal membrane oxygenation. Using CTA, several small clots were identified in the shunt as well as stenosis of the left pulmonary artery; neither of which were identified with echocardiography. The CTA allowed for quick identification of the disorder and helped direct prompt surgical intervention.

Role of low kilovoltage electrocardiographic-gated multidetector CT in electrophysiological procedures in the paediatric age group

Treatment of arrhythmias by catheter ablation targeting the anatomical foci of arrhythmias by radiofrequency has evolved dramatically in recent years. A road map for the relevant heart structures is an important asset for the success of the procedure and should be obtained before the intervention. This can be achieved by intra-cardiac echocardiography, conventional angiographic methods, multidetector CT, or MRI. The electrophysiological technique comprises a diagnostic procedure and an interventional - therapeutic - procedure. Electrocardiographic-gated multidetector CT is important in the diagnostic session to evaluate the anatomical details in combination with electric activity mapping. This combined protocol provides a unique view of the propagation of electrical activity, either normal or abnormal, over cardiac structures and allows a precise functional and anatomical evaluation to be obtained. In this review, we evaluate the role of electrocardiographic-gated multidetector CT in roadmapping arrhythmias in the paediatric age group, focussing on its strengths; we also evaluated some additional aspects that need further improvement in the future.

Patient radiation doses in paediatric interventional cardiology procedures: a review

A large number of investigations into the radiation doses from x-ray guided interventional cardiology procedures in children have been carried out in recent years. A review was conducted of these studies, gathering data on kerma area product (P KA), fluoroscopic screening time (FT), air kerma, and estimates of effective dose and organ doses. The majority of studies focus on P KA and FT with no estimation of dose to the patient. A greater than ten-fold variation in average P KA was found between different studies, even where data were stratified by patient age or weight. Typical values of P KA were 0.6-10 Gy · cm2 (<1 year/10 kg), 1.5-30 Gy · cm2 (1-5 years), 2-40 Gy · cm2 (5-10 years), 5-100 Gy · cm2 (10-16 years) and 10-200 Gy · cm2 (>16 years). P KA was lowest for heart biopsy (0.3-10 Gy · cm2 for all ages combined) and atrial septostomy (0.4-4.0 Gy · cm2), and highest for pulmonary artery angioplasty (1.5-35 Gy · cm2) and right ventricular outflow tract dilatation (139 Gy · cm2). Most estimates of patient dose were in the form of effective dose (typically 3-15 mSv) which is of limited usefulness in individualised risk assessment. Few studies estimated organ doses. Despite advances in radiation protection, recent publications have reported surprisingly large doses, as represented by P KA and air kerma. There is little indication of a fall in these dose indicators over the last 15 years. Nor is there much suggestion of a fall in doses associated with the use of flat panel detectors, as opposed to image intensifiers. An assessment of the impact of radiation dose in the context of overall patient outcome is required.

Radiation dose reduction in paediatric coronary computed tomography: assessment of effective dose and image quality

OBJECTIVES

To assess the impact of different protocols on radiation dose and image quality for paediatric coronary computed tomography (cCT).

MATERIALS AND METHODS

From January-2012 to June-2014, 140 children who underwent cCT on a 64-slice scanner were included. Two consecutive changes in imaging protocols were performed: 1) the use of adaptive statistical iterative reconstruction (ASIR); 2) the optimization of acquisition parameters. Effective dose (ED) was calculated by conversion of the dose-length product. Image quality was assessed as excellent, good or with significant artefacts.

RESULTS

Patients were divided in three age groups: 0-4, 5-7 and 8-18 years. The use of ASIR combined to the adjustment of scan settings allowed a reduction in the median ED of 58 %, 82 % and 85 % in 0-4, 5-7 and 8-18 years group, respectively (7.3 ± 1.4 vs 3.1 ± 0.7 mSv, 5.5 ± 1.6 vs 1 ± 1.9 mSv and 5.3 ± 5.0 vs 0.8 ± 2.0 mSv, all p < 0,05). Prospective protocol was used in 51 % of children. The reduction in radiation dose was not associated with reduction in diagnostic image quality as assessed by the frequency of coronary segments with excellent or good image quality (88 %).

CONCLUSIONS

cCT can be obtained at very low radiation doses in children using ASIR, and prospective acquisition with optimized imaging parameters.

KEY POINTS

• Using ASIR allows 25 % to 41 % reduction in the ED. • Prospective protocol is used up to 51 % of children after premedication. • Low dose is possible using ASIR and optimized prospective paediatric cCT.

The lateral plane delivers higher dose than the frontal plane in biplane cardiac catheterization systems

The objective of the study is to compare radiation dose between the frontal and lateral planes in a biplane cardiac catheterization laboratory. Tube angulation progressively increases patient and operator radiation dose in single-plane cardiac catheterization laboratories. This retrospective study captured biplane radiation dose in a pediatric cardiac catheterization laboratory between April 2010 and January 2014. Raw and time-indexed fluoroscopic, cineangiographic and total (fluoroscopic + cineangiographic) air kerma (AK, mGy) and kerma area product (PKA, µGym(2)/Kg) for each plane were compared. Data for 716 patients were analyzed: 408 (56.98 %) were male, the median age was 4.86 years, and the median weight was 17.35 kg. Although median beam-on time (minutes) was 4.2 times greater in the frontal plane, there was no difference in raw median total PKA between the two planes. However, when indexed to beam-on time, the lateral plane had a higher median-indexed fluoroscopic (0.75 vs. 1.70), cineangiographic (16.03 vs. 24.92), and total (1.43 vs. 5.15) PKA (p < 0.0001). The median time-indexed total PKA in the lateral plane is 3.6 times the frontal plane. This is the first report showing that the lateral plane delivers a higher dose than the frontal plane per unit time. Operators should consciously reduce the lateral plane beam-on time and incorporate this practice in radiation reduction protocols.

Cardiovascular magnetic resonance catheterization derived pulmonary vascular resistance and medium-term outcomes in congenital heart disease

BACKGROUND

Selection of patients with congenital heart disease for surgical septation in biventricular repair or surgical palliation in functionally single ventricles requires low pulmonary vascular resistance (PVR). Where there is uncertainty, PVR can be assessed using hybrid cardiovascular magnetic resonance (CMR) and fluoroscopic (X-Ray) guided cardiac catheterizations (XMR). CMR/XMR catheterization is a validated technique for accurate assessment of pulmonary vascular resistance. However, data concerning its application in clinical practice is lacking.

METHODS

PVR assessments were performed in 167 studies in 149 congenital heart disease patients by CMR/XMR catheterization. Data was collated on patient demographics, procedural data, complications and outcomes. Institutional ethics approval was obtained.

RESULTS

Median age was 3.6 years (6 days-67 years) and weight 13.8 kg (2.3-122 kg). One hundred and eight studies were in biventricular circulations and 59 in functionally single ventricles. Median radiation dose was 0.72 mSv. A baseline Qp:Qs ≤2.75 in biventricular circulations with left-to-right shunts predicted a PVR ≥6 WU x m(2) with 100% sensitivity and 48% specificity. Median follow up until death or last review was 4.2 years (4 days-11 years). Eighty-four patients had a surgical or catheter intervention based on CMR/XMR catheterization findings at a median of 94 days after the study. This included successful biventricular repair at resting PVR values ≤6 WU x m(2) and Fontan completion at  ≤4 WU x m(2).

CONCLUSION

PVR measured by CMR/XMR catheterization allows accurate stratification for intervention in patients with congenital heart disease in both, biventricular and univentricular circulations.

Radiation doses from fluoroscopically guided cardiac catheterization procedures in children and young adults in the United Kingdom: a multicentre study

OBJECTIVE

To gather data on radiation doses from fluoroscopically guided cardiac catheterization procedures in patients aged under 22 years at multiple centres and over a prolonged period in the UK. To evaluate and explain variation in doses. To estimate patient-specific organ doses and allow for possible future epidemiological analysis of associated cancer risks.

METHODS

Patient-specific data including kerma area product and screening times from 10,257 procedures carried out on 7726 patients at 3 UK hospitals from 1994 until 2013 were collected. Organ doses were estimated from these data using a dedicated dosimetry system based on Monte Carlo computer simulations.

RESULTS

Radiation doses from these procedures have fallen significantly over the past two decades. The organs receiving the highest doses per procedure were the lungs (median across whole cohort, 20.5 mSv), heart (19.7 mSv) and breasts (13.1 mSv). Median cumulative doses, taking into account multiple procedures, were 23.2, 22.2 and 16.7 mSv for these organs, respectively. Bone marrow doses were relatively low (median per procedure, 3.2 mSv; cumulative, 3.6 mSv).

CONCLUSION

Most modern cardiac catheterizations in children are moderately low-dose procedures. Technological advances appear to be the single most important factor in the fall in doses. Patients undergoing heart transplants undergo the most procedures. An epidemiological assessment of cancer risks following these procedures may be possible, especially using older data when doses were higher.

ADVANCES IN KNOWLEDGE

This is the first large-scale, patient-specific assessment of organ doses from these procedures in a young population.

Williams-Beuren syndrome: computed tomography imaging review

Williams-Beuren syndrome (WBS) affects young infants and children. The underlying etiopathogenesis of this rare disease is due to the mutation of the elastin gene that is responsible for the elasticity of the arterial wall. As a result of inadequate elastin production, the major systemic arteries become abnormally rigid and can be manifested by an impediment to the blood flow. The most common cardiovascular abnormalities encountered in WBS are supravalvular aortic stenosis, pulmonary arterial stenosis, and mitral valve prolapse. Less frequently observed cardiovascular abnormalities include coarctation of the aorta, ventricular septal defect, patent ductus, subaortic stenosis, and hypertrophic cardiomyopathy. Coronary artery stenosis and severe impediment to the bi-ventricular outflow as a result of supravalvular aortic and pulmonary artery stenosis predispose patients to sudden death. Patients with progressed arterial stenosis and severe stenosis are likely to require intervention to prevent serious complications. Rarely, imaging findings may precede clinical presentation, which allows the radiologist to participate in the patient care. However, to be more prudent, the radiologist must be accustomed to the imaging characteristics of WBS as well as the patient's clinical information, which could raise the suspicion of WBS. We performed a retrospective analysis of all the available images from patients diagnosed with WBS in last 4 years at our institution, and present key imaging findings along with a review of the literature to summarize the clinically relevant features as demonstrated by multidetector computed tomography in WBS. Cross-sectional imaging plays a vital role in the diagnosis of WBS cases with equivocal clinical features. MDCT evaluation of complex cardiovascular abnormalities of WBS including coronary artery disease is feasible with modern MDCT scanners and in the future, this approach could provide accurate information for planning, navigation, and noninvasive assessment of the secondary arterial changes in WBS and thus reducing the dependence upon invasive contrast catherization techniques.

Imaging in congenital pulmonary vein anomalies: the role of computed tomography

Pulmonary venous anomalies comprise a wide spectrum of anatomical variations and their clinical presentations may vary from the relatively benign single partial anomalous pulmonary venous connection (PAPVC) to the critical obstructed total anomalous pulmonary venous connection (TAPVC). We briefly review the common anomalies encountered, while highlighting the utility that computed tomographic angiography (CTA) provides for this spectrum of extracardiac vascular malformations and connections. CTA has established itself as an invaluable imaging modality in these patients. A detailed knowledge of the CTA imaging findings in pulmonary venous anomalies is crucial to guide clinical decision-making in these patients.

Treatment of femoral artery thrombosis with streptokinase and heparin after cardiac catheterization

Background:

Thrombosis is the most common complication during cardiac catheterization via femoral artery access. Alongside heparinization, fibrinolytic therapy is recommended if there are signs of ischemia in the lower extremity.

Objectives:

Given the paucity of data in the existing literature on streptokinase (SK) therapy in pediatrics, we designed this study to assess the efficacy of SK in pediatric patients with diagnosed femoral artery thrombosis following cardiac catheterization.

Patients and Methods:

The study population initially consisted of 1788 pediatric patients who underwent cardiac catheterization via the femoral artery access. Diminished or absent pulses in the lower extremity were detected in 123 patients, 45 of whom (2.5% of 1788) required treatment and were therefore considered for the next stage of study. Treatment was comprised of post-procedural intravenous heparin, either 50 U/kg/Q4h or 10 - 20 U/kg/h continuously. After heparinization for 24 hours, if the pulse of the affected extremity was not palpable, heparin therapy was continued (heparin-treated group, n = 28), and if the symptoms of femoral artery ischemia were persistent, heparin was discontinued and intravenous SK with a loading dose of 2000 U/kg over 20 - 30 minutes was commenced (SK-treated group, n =17).

Results:

In the presence of pulselessness in the lower extremity, a maintenance dose of SK (1000 U/kg/h, during 1 - 24 hours) was intravenously administered. Regarding the return of the pulses post-therapeutically, normal and weak/absent pulses were detected in seven (25.2%) and 21 (74.8%) of the 28 patients, respectively, in the heparin-treated group (P value < 0.001), whereas normal and weak/absent pulses were detected in 15 (88.2%) and two (11.8%) of the 17 patients, respectively, in the SK-treated group (P value < 0.001).

Conclusions:

Our findings demonstrated a high success rate and a low complication rate for systemic SK therapy in femoral artery thrombosis after catheterization.

Radiation dose reduction in pediatric cardiac computed tomography: experience from a tertiary medical center

Cardiac CT angiography (cCTA) has become an established method for the assessment of congenital heart disease. However, the potential harmful effects of ionizing radiation must be considered, particularly in younger, more radiosensitive patients. In this study, we sought to assess the temporal change in radiation doses from pediatric cCTA during an 8-year period at a tertiary medical center. This retrospective study included all patients ≤18 years old who were referred to electrocardiography (ECG)-gated cCTA for the assessment of congenital heart disease or inflammatory disease (Kawasaki disease) from November 2004 to September 2012. During the study period, 95 patients were scanned using 3 different scanner models-64-slice multidetector CT (64-MDCT) and first- (64-DSCT) and second-generation (128-DSCT) dual-source CT-and 3 scan protocols-retrospective ECG-gated helical scanning (RG), prospective ECG-triggered axial scanning (PT), or prospective ECG-triggered high-pitch helical scanning (HPH). Effective dose (ED) was calculated with the dose length product method with a conversion factor (k) adjusted for age. ED was then compared among scan protocols. Image quality was extracted from clinical cCTA reports when available. Overall, 94 % of scans were diagnostic (80 % for 64-slice MDCT, 93 % for 64-slice DSCT, and 97 % for 128-slice DSCT).With 128-DSCT, median ED (1.0 [range 0.6-2.0] mSv) decreased by 85.8 % and 66.8 % compared with 64-MDCT (6.8 [range 2.9-13.6] mSv) and 64-DSCT (2.9 [range 0.9-4.1] mSv), respectively. With HPH, median ED (0.9 [range 0.6-1.8] mSv) decreased by 59.4 % and 85.4 % compared with PT (2.2 [range 0.9-3.4] mSv) and RG (6.1 [range 2.5-10.6] mSv). cCTA can now be obtained at very low radiation doses in pediatric patients using the latest dual-source CT technology in combination with prospective ECG-triggered HPH acquisition.

Cardiovascular imaging trends in congenital heart disease: a single center experience

BACKGROUND

Cardiac magnetic resonance imaging (MRI) and CT are available in the recent era at many pediatric cardiac centers.

OBJECTIVE

The aim was to provide a contemporary description of diagnostic imaging trends for definition of congenital heart disease (CHD).

METHODS

Echocardiography, cardiac catheterization, cardiac MRI, and cardiac CT use in patients with congenital heart disease at a single institution was retrospectively recorded (2005-2012). Surgical procedures were recorded. Total and modality-specific rates were estimated by Poisson regression and compared. The median age, studies in patients aged >17 years, and referral diagnosis were tabulated for the last year of review.

RESULTS

An average of 11,940 cardiovascular diagnostic tests was performed annually. The number of total studies, echocardiograms, catheterizations, and surgical procedures, did not change significantly across time. Echocardiography comprised 95% to 97% of all studies performed during each year of review. The use of cardiac MRI (2%) and cardiac CT (1%) increased linearly (P < .001), and the use of diagnostic catheterization decreased (0.7%; P = .0005). The median age was 3 years for echocardiography, 15 years for MRI, 11 years for CT, and 3 years for catheterization. The percentage of patients aged >17 years was 9% for echocardiography, 33% for cardiac MRI, 29% for cardiac CT, and 8% for catheterization. Most patients undergoing CT, MRI, and diagnostic catheterization had moderate or complex CHD.

CONCLUSION

Cardiac CT is used increasingly in the recent era for evaluation of CHD. The increased use of both cardiac CT and cardiac MRI are temporally associated with a decrease in diagnostic cardiac catheterization.

Cardiovascular manifestations of Williams syndrome: imaging findings

Williams syndrome is a relatively common (1 in 10,000 live births) genetic disorder caused by a deletion involving chromosome 7 that results in a variety of clinically significant abnormalities, including developmental delay, behavioral changes, hypercalcemia, and a distinct "elfin" facial appearance. Congenital cardiovascular disease that presents in childhood is responsible for most of the morbidity and mortality associated with this disorder. The purpose of this pictorial essay is to review imaging findings of some of the more common cardiovascular manifestations of Williams syndrome and to highlight some of the unique anatomic variations that can be seen in these patients.