CT and MR imaging in congenital cardiac malformations: Where do we come from and where are we going?

Assessment of deep learning image reconstruction (DLIR) on image quality in pediatric cardiac CT datasets type of manuscript: Original research

BAKGROUND

To evaluate the quantitative and qualitative image quality using deep learning image reconstruction (DLIR) of pediatric cardiac computed tomography (CT) compared with conventional image reconstruction methods.

METHODS

Between January 2020 and December 2022, 109 pediatric cardiac CT scans were included in this study. The CT scans were reconstructed using an adaptive statistical iterative reconstruction-V (ASiR-V) with a blending factor of 80% and three levels of DLIR with TrueFidelity (low-, medium-, and high-strength settings). Quantitative image quality was measured using signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The edge rise distance (ERD) and angle between 25% and 75% of the line density profile were drawn to evaluate sharpness. Qualitative image quality was assessed using visual grading analysis scores.

RESULTS

A gradual improvement in the SNR and CNR was noted among the strength levels of the DLIR in sequence from low to high. Compared to ASiR-V, high-level DLIR showed significantly improved SNR and CNR (P<0.05). ERD decreased with increasing angle as the level of DLIR increased.

CONCLUSION

High-level DLIR showed improved SNR and CNR compared to ASiR-V, with better sharpness on pediatric cardiac CT scans.

Photon-counting versus Dual-Source CT of Congenital Heart Defects in Neonates and Infants: Initial Experience

Background Photon-counting CT (PCCT) has been shown to improve cardiovascular CT imaging in adults. Data in neonates, infants, and young children under the age of 3 years are missing. Purpose To compare image quality and radiation dose of ultrahigh-pitch PCCT with that of ultrahigh-pitch dual-source CT (DSCT) in children suspected of having congenital heart defects. Materials and Methods This is a prospective analysis of existing clinical CT studies in children suspected of having congenital heart defects who underwent contrast-enhanced PCCT or DSCT in the heart and thoracic aorta between January 2019 and October 2022. CT dose index and dose-length product were used to calculate effective radiation dose. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated by standardized region-of-interest analysis. SNR and CNR dose ratios were calculated. Visual image quality was assessed by four independent readers on a five-point scale: 5, excellent or absent; 4, good or minimal; 3, moderate; 2, limited or substantial; and 1, poor or massive. Results Contrast-enhanced PCCT (n = 30) or DSCT (n = 84) was performed in 113 children (55 female and 58 male participants; median age, 66 days [IQR, 15-270]; median height, 56 cm [IQR, 52-67]; and median weight, 4.5 kg [IQR, 3.4-7.1]). A diagnostic image quality score of at least 3 was obtained in 29 of 30 (97%) with PCCT versus 65 of 84 (77%) with DSCT. Mean overall image quality ratings were higher for PCCT versus DSCT (4.17 vs 3.16, respectively; P < .001). SNR and CNR were higher for PCCT versus DSCT with SNR (46.3 ± 16.3 vs 29.9 ± 15.3, respectively; P = .007) and CNR (62.0 ± 50.3 vs 37.2 ± 20.8, respectively; P = .001). Mean effective radiation doses were similar for PCCT and DSCT (0.50 mSv vs 0.52 mSv; P = .47). Conclusion At a similar radiation dose, PCCT offers a higher SNR and CNR and thus better cardiovascular imaging quality than DSCT in children suspected of having cardiac heart defects. © RSNA, 2023.

Screening and diagnostic imaging at centres performing congenital heart surgery in middle-income countries

BACKGROUND

Surgical care for CHD is increasingly available in low- and middle-income countries, and efforts to optimise outcomes are growing. This study characterises cardiac imaging and prenatal diagnosis infrastructure in this setting.

METHODS

An infrastructure survey was administered to sites participating in the International Quality Improvement Collaborative for CHD. Questions regarding transthoracic, transesophageal and epicardial echocardiography, cardiac CT, cardiac magnetic resonance, prenatal screening and fetal echocardiography were included. Associations with in-hospital and 30-day mortality were assessed.

RESULTS

Thirty-seven sites in 17 countries responded. Programme size and geography varied considerably: < 250 cases (n = 13), 250-500 cases (n = 9), > 500 cases (n = 15); Americas (n = 13), Asia (n = 18), and Eastern Europe (n = 6). All had access to transthoracic echo. Most reported transesophageal and epicardial echocardiography availability (86 and 89%, respectively). Most (81%) had cardiac CT, but only 54% had cardiac magnetic resonance. A third reported impediments to imaging, including lack of portable machines, age/size-appropriate equipment and advanced cardiac imaging access and training. Only 19% of centres reported universal prenatal CHD screening in their catchment area, and only 46% always performed fetal echocardiography if screening raised concern for CHD. No statistically significant associations were identified between imaging modality availability and surgical outcomes.

CONCLUSIONS

Although access to echocardiography is available in most middle-income countries; advanced imaging modalities (cardiac CT and magnetic resonance) are not always accessible. Prenatal screening for CHD is low, and availability of fetal echocardiography is limited. Imaging infrastructure in low- and middle-income countries and associations with outcomes merits additional study.

Utility of cardiac CT in infants with congenital heart disease: Diagnostic performance and impact on management

BACKGROUND

Advances in cardiac CT (CCT) scanner technology allow imaging without anesthesia, and with low radiation dose, making it an attractive technique in infants with congenital heart disease. However, the utility of CCT using a dual-source scanner with respect to diagnostic performance and impact on management has not been systematically studied in this population.

METHODS

Retrospective review of infants who underwent CCT to determine the utility of CCT with respect to the following: answering the primary diagnostic question, providing new diagnostic information, prompting a change in management, and concordance with catheterization or surgical inspection.

RESULTS

A total of 156 infants underwent 172 scans at a median age of 64 days, (IQR 4-188) from Jan 2016-Dec 2019. The most frequent diagnostic question was related to the pulmonary arteries (43%), followed by the aortic arch (30%), pulmonary veins (26%), coronary arteries (17%), patent ductus arteriosus (10%) and others (9%). A high-pitch spiral scan was frequently used (90%). The median effective radiation dose was low (0.66 ​mSv) and general anesthesia was used infrequently (23%). CCT answered the primary diagnostic question in 168/172 (98%) and added to the diagnostic information already available by echocardiography in 161/172 (96%) scans. CCT led to a change in management following 78/172 (53%) scans and had an impact on management following 167/172 (97%) scans. On follow-up, after 107/172 (62%) scans, subjects underwent cardiac surgery, and after 55/172 (32%) scans, they had cardiac catheterization. CCT findings were concordant with catheterization and/or surgical inspection in 156/159 (98%) scans.

CONCLUSIONS

In infants with complex congenital heart disease, CCT was accurate, answered the diagnostic questions in nearly all cases, and frequently added diagnostic information that impacted management. Radiation exposure was low, and anesthesia was needed infrequently.

Surgical management of lesions encountered in the setting of the retroaortic left brachiocephalic vein

BACKGROUND AND AIM

Although the retroaortic left brachiocephalic vein in isolation is of no clinical importance, its recognition in the setting of associated lesions is important. We sought to address issues concerning the influence of isomerism, the establishment of diagnosis, and its importance in various surgical and interventional procedures.

METHODS

A total of 80 published clinical and necropsy studies in the setting of a retroaortic left brachiocephalic vein described 250 patients. Clinical presentation, radiographic, ultrasonographic findings, contrast echocardiography, computed-tomographic angiocardiography, magnetic resonance imaging, and angiocardiography provided the diagnostic information prior to considering the surgical approach to the associated cardiac anomalies.

RESULTS

Among 250 reported cases, three-quarters had associated congenitally malformed hearts. Of these 189 patients, all but seven had usual atrial arrangement. Right isomerism was reported in five patients and two patients having left isomerism. Almost two-thirds had tetralogy of Fallot or its variants, over four-fifths had malformations involving the outflow tract, two-thirds had a right aortic arch with two patients having a cervical aortic arch, and onepatient had double aortic arch. Various innovative individualized surgical procedures were employed with an overall perioperative mortality of 3.4%.

CONCLUSIONS

Although the retroaortic left brachiocephalic vein is asymptomatic, its recognition during clinical investigation should raise the possibility of an association with other malformations, especially right aortic arch, ventricular septal defect, and anomalies of the outflow tracts. We submit that an increased appreciation of this venous anomaly may facilitate surgical planning, endovascular procedures, placement of central venous lines, and transvenous pacemakers.

Chest CTA in children younger than two years - a retrospective comparison of three contrast injection protocols

To obtain the highest diagnostic information with least side effects when performing thoracic CT angiography (CTA) is challenging in young children. The current study aims to compare three contrast agent (CA) injection protocols regarding image quality and CA characteristic: a standard CTA, a fixed-bolus delay protocol, and the “microbolus technique (MBT)” developed in our institution. Seventy chest CTA scans of patients (<2 years) were divided into three groups. MBT was applied in group I, the standard protocol in group II and a fixed bolus delay in group III. Objective image quality was assessed by measuring peak enhancement, image noise, signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Two observers scored subjective image quality and artifacts. Significantly lower amounts of CA (mean ± SD) were used in the MBT group compared to Group II (9.0 ± 3.7 ml vs. 12.9 ± 4.5 ml). A lower, but still diagnostic (>400 HU) enhancement was registered in all major thoracic vessels in group I without significant differences regarding SNR and CNR in most regions (p < 0.05). The best scores for image quality and artifacts were reached in group I. All three chest CTA contrast injection protocols offered diagnostic vessel enhancement in young patients. MBT was associated with reduced image artifacts and less injected CA.

Diagnostic Accuracy of Noncontrast Self-navigated Free-breathing MR Angiography versus CT Angiography: A Prospective Study in Pediatric Patients with Suspected Anomalous Coronary Arteries

RATIONALE AND OBJECTIVES

To evaluate the diagnostic accuracy of a prototype noncontrast, free-breathing, self-navigated 3D (SN3D) MR angiography (MRA) technique for the assessment of coronary artery anatomy in children with known or suspected coronary anomalies, using CT angiography (CTA) as the reference standard.

MATERIALS AND METHODS

Twenty-one children (15 male, 12.3 ± 2.6 years) were prospectively enrolled between July 2014 and August 2016 in this IRB-approved, HIPAA-compliant study. Patients underwent same-day unenhanced SN3D-MRA and contrast-enhanced CTA. Two observers rated the visualization of coronary artery segments and diagnostic confidence on a 3-point scale and assessed coronary arteries for anomalous origin, as well as interarterial and intramural course. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of SN3D-MRA for the detection of coronary artery abnormalities were calculated. Interobserver agreement was assessed using Intraclass Correlation Coefficients (ICC).

RESULTS

Fourteen children showed coronary artery abnormalities on CTA. The visualization of coronary segments was rated significantly higher for CTA compared to MRA (p <0.015), except for the left main coronary artery (p = 0.301), with good to excellent interobserver agreement (ICC = 0.62-0.94). Diagnostic confidence was higher for CTA (p = 0.046). Sensitivity, specificity, PPV, and NPV of MRA were 92%, 92%, 96%, and 87% for the detection of coronary artery anomalies, 85%, 85%, 74%, and 92% for high origin, 71%, 92%, 82%, and 87% for interarterial, and 41%, 96%, 87%, and 80% for intramural course.

CONCLUSIONS

Noncontrast SN3D-MRA is highly accurate for the detection of coronary artery anomalies in pediatric patients while diagnostic confidence and coronary artery visualization remain superior with CTA.

Advanced Cardiac Imaging for Complex Adult Congenital Heart Diseases

The population of patients with adult congenital heart disease has grown and is currently estimated to include approximately 1 million people in the United States. Cardiologists and imagers frequently encounter complex patients who have undergone multiple prior operations and interventions. A myriad of imaging tests are currently available, including echocardiography, cardiovascular magnetic resonance imaging, and computed tomography, all of which collectively provide invaluable information on cardiac anatomy and hemodynamics. Advanced imaging plays a role in diagnosis and preprocedural planning and also determines the need and frequency of follow-up. This article provides a contemporary review of the current role of cardiac imaging in patients with complex congenital heart disease.

Tetralogy of Fallot With Right Aortic Arch and Retro-Aortic Innominate Vein

Right aortic arch (RAA) and retro-aortic innominate vein are rare vascular anomalies. Diagnosis of these anatomical variations can be achieved using fetal echocardiography, post-natal echocardiography, and computed tomography scan. RAA can form a vascular ring when associated with other vascular anomalies which may compress the trachea and/or esophagus. On the other hand, the existence of retro-aortic innominate vein can influence the clinical decision-making and surgical strategy. We report a rare occurrence of both RAA and retro-aortic innominate vein in a 3 months old girl with a prenatal diagnosis of tetralogy of Fallot and include details of her presentation and successful management.