Computed tomography imaging in children with congenital heart disease: Indications and radiation dose optimization

Topography of the Heart: Mapping the Fetal Heart Through SlowflowHD

SlowflowHD is a Doppler Ultrasound modality that is typically geared toward visualization of small-size vessels and low velocity blood flow. In this commentary, we emphasize the importance of implementing the use of SlowflowHD as an adjunct to traditional Doppler modalities in the echocardiography screening in both the first and second trimester. This modality carries many characteristics that allow it to overcome the limitations of our current ultrasound modalities and facilitate mapping of the entirety of the fetal heart. The clinical implications are significant in regard to earlier acquisition of diagnostic information to guide decision-making and patient counseling.

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.

Diagnostic Validity and Reliability of Low-Dose Prospective ECG-Triggering Cardiac CT in Preoperative Assessment of Complex Congenital Heart Diseases (CHDs)

For the precise preoperative evaluation of complex congenital heart diseases (CHDs) with reduced radiation dose exposure, we assessed the diagnostic validity and reliability of low-dose prospective ECG-gated cardiac CT (CCT). Forty-two individuals with complex CHDs who underwent preoperative CCT as part of a prospective study were included. Each CCT image was examined independently by two radiologists. The primary reference for assessing the diagnostic validity of the CCT was the post-operative data. Infants and neonates were the most common age group suffering from complex CHDs. The mean volume of the CT dose index was 1.44 ± 0.47 mGy, the mean value of the dose-length product was 14.13 ± 5.4 mGy*cm, and the mean value of the effective radiation dose was 0.58 ± 0.13 mSv. The sensitivity, specificity, PPV, NPV, and accuracy of the low-dose prospective ECG-gated CCT for identifying complex CHDs were 95.6%, 98%, 97%, 97%, and 97% for reader 1 and 92.6%, 97%, 95.5%, 95.1%, and 95.2% for reader 2, respectively. The overall inter-reader agreement for interpreting the cardiac CCTs was good (κ = 0.74). According to the results of our investigation, low-dose prospective ECG-gated CCT is a useful and trustworthy method for assessing coronary arteries and making a precise preoperative diagnosis of complex CHDs.

320 cardiac MDCT angiography in preoperative assessment of TOF and its variants: Does it worth it?

Background

Tetralogy of Fallot is the most common cyanotic congenital heart disease encountering a large spectrum of anatomical presentations with differing surgical approaches, and long-term outcomes ranging from ventricular septal defect with limited aortic overriding and mild pulmonary obstruction to a critical form of VSD and pulmonary atresia. TOF variants include PA/VSD, TOF/CAVC, TOF/DORV and TOF with absent pulmonary valve. Also, it may be accompanied with many associated intracardiac and extracardiac anomalies that may be of value when imaging and planning the surgical procedure.

Results

Our study included 22 cases of classic TOF, 18 with PA/VSD (12 were of type A, 5 were of type B and 1 was of type C), 3 with TOF/CAVC and 7 TOF/DORV. Sub-valvular RVOTO was detected in 94% of patients. A statistically significant difference was depicted between Echocardiography and MDCT in detecting supravalvular RVOTO, however no statistically significant difference was found in sub-valvular and valvular RVOTO detection. MDCT could efficiently characterize pulmonary arterial tree with statistically significant difference between both Echocardiography and MDCT in assessment of main, right and left pulmonary arteries with P value = 0.036,0.014 and 0.023 respectively. With calculation of Mc-Goon ratio in all patients, it was favorable (> 1.2) in 33 patients (66%). MDCT entailed 19 patients with PDA versus 15 depicted by Echocardiography and 25 MAPCAs per 11patients compared 8 MAPCAs per 7 patients detected by Echocardiography. Right sided aortic arch was found in 10 patients and 24 patients showed abnormal branching pattern. Coronary artery abnormalities were identified in eight patients. MDCT showed 100% sensitivity and 100% specificity in depicting aortic, coronary and other associated extracardiac vascular anomalies.

Conclusion

MDCT offers comprehensive anatomical assessment of TOF, and its variants providing superiority over echocardiography and comparable results to cardiac catherization with 100% sensitivity and specificity in evaluation of associated extracardiac vascular anomalies as well as pulmonary arteries characterization. It is worth using MDCT routinely in combination with echocardiography for the preoperative assessment of TOF and its variants representing a less invasive option than conventional catherization with lower radiation exposure.

Diagnostic accuracy of lower-dose cardiac CT in evaluating young infants with non-coronary complex congenital heart disease on a 64-slice multidetector CT scanner

Background

Redoable precise and non-invasive diagnostic imaging modality with the least radiation dose is essential for infants with congenital heart disease (CHD) .

Purpose

To investigate the accuracy and estimate the radiation dose of our cardiac computed tomography (CCT) protocol.

Material and Methods

A total of 82 infants with CHD underwent non-ECG-gated CCT without contrast timing scanning techniques and were retrospectively studied. The image quality and radiation dose were estimated. The radiation dose was compared statistically to virtual retrospective ECG-gated and prospective ECG-triggering scanning modes. The diagnostic accuracy was assessed assuming the surgical results as the diagnostic gold standard.

Results

Most exams showed a high quality with low radiation doses compared to previous studies. The mean effective dose (ED) was 0.39 ± 1.2, significantly lower than that of the virtual retrospective ECG-gated and prospective ECG-triggering scanning and lower than in previous studies. Our CCT protocol has achieved a diagnostic accuracy of 99.52% with a sensitivity of 94.83% and specificity of 99.91%.

Conclusion

Non-ECG-gated CCT without contrast timing techniques can detect the non-coronary cardiovascular defects of CHD in infants with an ultralow radiation dose and a high diagnostic accuracy.

Optimizing neonatal cardiac imaging (magnetic resonance/computed tomography)

Magnetic resonance imaging (MRI) and CT perform an important role in the evaluation of neonates with congenital heart disease (CHD) when echocardiography is not sufficient for surgical planning or postoperative follow-up. Cardiac MRI and cardiac CT have complementary applications in the evaluation of cardiovascular disease in neonates. This review focuses on the indications and technical aspects of these modalities and special considerations for imaging neonates with CHD.

Indications and outcomes of cardiac catheterization following congenital heart surgery in children

OBJECTIVES

Our goal was to evaluate the indications for postoperative cardiac catheterizations after paediatric cardiac surgeries and their impact on outcomes.

METHODS

Non-planned cardiac catheterizations performed after congenital heart surgeries and before discharge between January 2013 and July 2019 were reviewed. Hybrid procedures were excluded. Heart defects, illness course, surgeries and catheter procedures were classified. Indications and findings were comprehensively regrouped. Outcomes were analysed.

RESULTS

Cardiac catheterizations were performed on 192 patients (median age 2.3 months, weight 4.2 kg) on median postoperative day 7 (interquartile range, 2-17 days). Patients had defects of great complexity (79.9%), high disease severity index (46.4%), high Aristotle level of surgical complexity (75%) and a high Catheterization RISk Score for Pediatrics category of catheterizations (61%). Catheterizations confirmed 66% of suspected diagnoses. Confirmed diagnoses were more likely to be haemodynamic anomalies than anatomical lesions (81.3% > 53.7%, P < 0.001). Confirmed anatomical lesions were more likely to be residual than new lesions created by surgery (88.5% > 40.4%, P < 0.001). New diagnoses were identified in 36.5% of patients. Catheterization findings led to catheter-based or surgical interventions in 120 (62.5%) patients. Transcatheter interventions were successful (97.7%), immediate (89.5%) and performed across fresh suture lines (27.8%). Repeat catheterizations (76% interventional) were necessary in 25 (13%) patients. A high index of disease severity [odds ratio (OR): 16.26, 95% confidence interval (CI): 3.72-71.17], extracorporeal membrane oxygenation support (OR: 10.35, 95% CI: 2.78-38.56), delayed sternal closure (OR: 4.66, 95% CI: 1.25-17.32) and surgically acquired lesions (OR: 3.70, 95% CI: 1.22-11.16) were significant risk factors of 12-month mortality.

CONCLUSIONS

Postoperative cardiac catheterizations answer both anatomical and haemodynamic questions in high-risk patients with complicated courses and guide subsequent treatment with satisfactory outcomes.

Overview of imaging in adult- and childhood-onset Takayasu arteritis

Takayasu Arteritis is an idiopathic large vessel vasculitis, that affects young adults and children and can lead to ischemia and end-organ damage. Vascular imaging is crucial for diagnosis, assessment of disease extent and management of the disease. In this article, we critically review evidence for the clinical use of the different imaging modalities conventional angiography, magnetic resonance imaging, computed tomography, Doppler ultrasound and ¹⁸fluorodeoxyglucose positron emission tomography. We thereby focus on their clinical applicability, challenges and specific use in children.

A Comparison of the Pulmonary Valve, Main Pulmonary Artery, and Branch Pulmonary Artery Measurements by Echocardiography and Computed Tomography Scan

Introduction: Congenital heart diseases (CHD) are one of the most commonly occurring congenital anomalies. Echocardiography is usually the initial investigation for suspected CHD. However, it is operator-dependent and limited by available chest windows. Multidetector computed tomography (MDCT) scan provides superior temporal and spatial resolution producing excellent cross-sectional anatomical images. MDCT is specifically helpful for pulmonary artery anomalies if not clearly visible on an echocardiogram.

Objective and methods: The study aims to compare measurements of branch pulmonary arteries, pulmonary valve, and main pulmonary artery obtained from trans-thoracic echocardiography measurements and MDCT. Forty-nine patients younger than 17 years of age underwent MDCT, and an echocardiogram was included in the study. The measurements of the pulmonary valve, main pulmonary artery, and branch pulmonary arteries were measured on MDCT and echocardiogram.

Results: Bland-Altman analysis revealed the mean difference (95% confidence limits) in measurements of diameter between echocardiogram and MDCT for the right pulmonary artery, left pulmonary artery, pulmonary valve, and main pulmonary artery, which were -0.5 (-3.1, 2.2) mm, -0.6 (-3.3, 2.1) mm, 0.7 (-2.5, 3.9) mm, and 1.2 (-6.9, 4.5) mm, respectively.

Conclusion: The analysis revealed acceptable agreement in measurements of the pulmonary valve, main pulmonary artery, and branch pulmonary arteries obtained from MDCT and echocardiogram. The difference was marginally more for the main pulmonary artery compared to the pulmonary valve and branch pulmonary arteries.

Non-invasive Imaging in the Evaluation of Cardiac Shunts for Interventional Closure

Multimodality imaging provides important information to guide patient selection and pre-procedural decision making for shunt lesions in CHD. While echocardiography, CT, and CMR are well-established, 3D printing and now virtual reality imaging are beginning to show promise.

Feasibility of using a non-sedation protocol for evaluation of neonatal congenital heart disease by using a 16-cm wide-detector computed tomography with a low radiation dose: preliminary experience from a single pediatric medical center

The aim of this study is to explore the feasibility of using a non-sedation protocol for the evaluation of neonatal congenital heart disease by using 16-cm wide-detector CT with a low radiation dose. Thirty-four neonates (group 1) were enrolled to undergo cardiac CT without sedation between August 2018 and March 2019. The control group (group 2) comprising 20 inpatient neonates was sedated. Cardiac CT was performed using 16-cm area detector 320-row CT with free breathing and prospective ECG-triggering scan mode. The examination completion time, radiation dose, and image quality were compared between the groups. The results of cardiac CT for patients in group 1 who underwent surgery were compared with surgical findings. Intergroup differences in body weight, age, examination completion time, radiation dose, and image quality evaluation were not significant. There was no significant difference in oxygen saturation before and after the examination in group 1. In all, 98 separate cardiovascular abnormalities in 27 group 1 patients were confirmed using surgical reports. The overall sensitivity, specificity, positive predictive value, and negative predictive value of cardiac CT were 94.90%, 100.0%, 100.0%, and 98.53%. The non-sedation protocol can be applied in neonates with congenital heart disease by using 16-cm wide-detector CT with a low radiation dose. Based on the image quality obtained, non-sedative examination did not extend the examination completion time and helped avoid the possible side effects of sedative drugs.

Cardiac CT angiography: normal and pathological anatomical features-a narrative review

The normal and pathological anatomy of the heart and coronary arteries are nowadays widely developed topics and constitute a fundamental part of the cultural background of the radiologist. The introduction of cardiac ECG-gated synchronized CT scanners with an ever-increasing number of detectors and with increasingly high structural characteristics (increase in temporal resolution, increase in contrast resolution with dual-source, dual energy scanners) allows the virtual measurement of anatomical in vivo structures complying with heart rate with submillimetric precision permitting to clearly depict the normal anatomy and follow the pathologic temporal evolution. Accordingly to these considerations, cardiac computed tomography angiography (CCTA) asserts itself as a gold standard method for the anatomical evaluation of the heart and permits to evaluate, verify, measure and characterize structural pathological alterations of both congenital and acquired degenerative diseases. Accordingly, CCTA is increasingly used as a prognostic model capable of modifying the outcome of diseased patients in planning interventions and in the post-surgical/interventional follow-up. The profound knowledge of cardiac anatomy and function through highly detailed CCTA analysis is required to perform an efficient and optimal use in real-world clinical practice.

Cardiac computed tomography angiography in the paediatric population: Expert consensus from the Filiale de cardiologie pédiatrique et congénitale (FCPC) and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV)

This paper aims to provide a paediatric cardiac computed tomography angiography expert panel consensus based on the opinions of experts from the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) and the Filiale de cardiologie pédiatrique congénitale (FCPC). This expert panel consensus includes recommendations for indications, patient preparation, computed tomography angiography radiation dose reduction techniques and postprocessing techniques. We think that to realize its full potential and to avoid pitfalls, cardiac computed tomography angiography in children with congenital heart disease requires training and experience. Moreover, paediatric cardiac computed tomography angiography protocols should be standardized to acquire optimal images in this population with the lowest radiation dose possible, to prevent unnecessary radiation exposure. We also provide a suggested structured report and a list of acquisition protocols and technical parameters in relation to specific vendors.

Pediatric cardiac computed tomography angiography: Expert consensus from the Filiale de Cardiologie Pédiatrique et Congénitale (FCPC) and the Société Française d'Imagerie Cardiaque et Vasculaire diagnostique et interventionnelle (SFICV)

This article was designed to provide a pediatric cardiac computed tomography angiography (CCTA) expert panel consensus based on opinions of experts of the Société Française d'Imagerie Cardiaque et Vasculaire diagnostique et interventionnelle (SFICV) and of the Filiale de Cardiologie Pédiatrique Congénitale (FCPC). This expert panel consensus includes recommendations for indications, patient preparation, CTA radiation dose reduction techniques, and post-processing techniques. The consensus was based on data from available literature (original papers, reviews and guidelines) and on opinions of a group of specialists with extensive experience in the use of CT imaging in congenital heart disease. In order to reach high potential and avoid pitfalls, CCTA in children with congenital heart disease requires training and experience. Moreover, pediatric cardiac CCTA protocols should be standardized to acquire optimal images in this population with the lowest radiation dose possible to prevent unnecessary radiation exposure. We also provided a suggested structured report and a list of acquisition protocols and technical parameters in relation to specific vendors.

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.

Quality Initiative to Reduce Cardiac CT Angiography Radiation Exposure in Patients with Congenital Heart Disease

Background

The use of cardiac computed tomography angiography (CCTA) as a complementary diagnostic modality to echocardiography in patients with congenital heart diseases (CHDs) is expanding in low- and middle-income countries. The adoption of As Low As Reasonably Achievable techniques is not widespread, resulting in significant unintended radiation exposure, especially in children. Simple quality improvement measures geared toward reducing radiation dose can have a impact on patient safety in resource-limited centers in low- and middle-income countries.

Objectives

To determine how a quality improvement initiative can reduce radiation exposure during CCTA in patients with CHD.

Methods

We designed a key driver -based quality initiative to reduce radiation dose during CCTA for CHD using protocol optimization, communication, and training and implementation as the drivers for intervention. Preintervention variables (radiation exposure, scanning protocols, and image quality) were collected from September 2012 to July 2016 and compared with variables in the postimplementation phase (February 2017 to July 2017). We compared quantitative and categorical variables using the chi-square test. Linear regression analysis was used to evaluate the effect of various factors on radiation dose.

Results

We documented a reduction in the effective dose in the postintervention versus preintervention phase (mean, 2.0 versus 21 mSv, P < 0.0001, respectively). Linear regression showed that the optimal organizational levels are associated with the same reduction in radiation. This finding shows that the time factor translates a combination of organizational and technical factors that contributed to the reduction in radiations.

Conclusions

Our project showed a reduction in CCTA-associated radiation exposure.

Comparison of echocardiography and 64-slice spiral computed tomography in the diagnosis of congenital heart disease in children

The diagnosis of congenital heart disease in children has been an issue in the medical community. Timely diagnosis and treatment can provide a greater guarantee for children's healthy growth. In recent years, there have been more and more studies on the diagnosis of congenital heart disease in children. This paper compares the advantages and disadvantages of echocardiography and 64-slice spiral computed tomography (CT) in the diagnosis of congenital heart disease in children. In clinical trials, we also tested 64 patients with spiral computed tomography (SCT) and transthoracic echocardiography (TTE) detection of patients and then confirmed the accuracy of the diagnosis by the surgical methods. The two methods of detection, the rate of missed diagnosis, and the rate of misdiagnosis were counted. Through the test results and pathological diagnosis results, the diagnostic accuracy of the two methods were all above 90%, each with its own advantages and disadvantages. The sensitivity of echocardiographic in detecting intracardiac structure abnormalities was relatively high, but when the diagnosis of extracardiac structural abnormalities less than 64-slice spiral CT method, misdiagnosis of TTE was mainly due to extracardiac vascular malformations. Therefore, it is recommended to combine the two methods to improve the diagnosis of congenital heart disease in children.

Update on the Role of Cardiac Magnetic Resonance Imaging in Congenital Heart Disease

OPINION STATEMENT

Cardiac magnetic resonance imaging (CMR) is an important imaging modality in the evaluation of congenital heart diseases (CHD). CMR has several strengths including good spatial and temporal resolutions, wide field-of-view, and multi-planar imaging capabilities. CMR provides significant advantages for imaging in CHD through its ability to measure function, flow and vessel sizes, create three-dimensional reconstructions, and perform tissue characterization, all in a single imaging study. Thus, CMR is the most comprehensive imaging modality available today for the evaluation of CHD. Newer MRI sequences and post-processing tools will allow further development of quantitative methods of analysis, and opens the door for risk stratification in CHD. CMR also can interface with computer modeling, 3D printing, and other methods of understanding the complex anatomic and physiologic relationships in CHD.

Comparison of 128-Slice Low-Dose Prospective ECG-Gated CT Scanning and Trans-Thoracic Echocardiography for the Diagnosis of Complex Congenital Heart Disease

Objective

To compare prospective ECG-gated multi-slice computed tomography (MSCT) and trans-thoracic echocardiography (TTE) in the diagnosis of complex congenital heart disease (CHD).

Methods

This was a prospective study of consecutive patients with complex CHD (age <7 years) treated at a tertiary hospital between May 2013 and May 2015. All patients were imaged with TTE and prospective ECG-gated 128-slice spiral CT in the week before surgery. Effective radiation dose (ED) was calculated from volume CT dose index (CTDIvol) and dose length product (DLP). Image quality (5-point scale) was assessed independently by two radiologists. Using surgical findings as the reference, the diagnostic capabilities of MSCT and TTE were compared.

Results

Thirty-five patients (19 males) aged 1.59±1.58 years (range, 3 days to 74 months) were included. CTDIvol, DLP and ED were 0.90±0.24 mGy, 12.9±4.7 mGy∙cm and 0.64±0.21 mSv (range, 0.358–1.196 mSv), respectively. Image quality score was 4.3±0.5, and all images met the diagnostic requirements. The sensitivity, specificity, positive predictive value, and negative predictive value for diagnosing CHD were 97.2%, 99.8%, 99.0%, and 99.5%, respectively, for MSCT, and 90.6%, 99.8%, 99.0%, and 98.4%, respectively, for TTE. MSCT not only had a higher sensitivity than TTE overall (97.2% vs. 90.6%; P<0.05), but was much more sensitive for the diagnosis of extracardiac vascular abnormalities (92.0% vs. 68.0%; P<0.05).

Conclusion

128-slice low-dose prospective ECG-gated CT scanning has important clinical value in the diagnosis of complex CHD in children, complementing and extending the findings of TTE.