Pediatric Cardiac Imaging Research Articles

Diagnostic Reference Levels in Pediatric Cardiac CT Imaging: A Literature Review

Diagnostic Reference Levels in Pediatric Cardiac CT Imaging: A Literature Review

Diagnostic Performance of Artificial Intelligence-Based Computer-Aided Detection and Diagnosis in Pediatric Radiology: A Systematic Review.

Artificial intelligence (AI)-based computer-aided detection and diagnosis (CAD) is an important research area in radiology. However, only two narrative reviews about general uses of AI in pediatric radiology and AI-based CAD in pediatric chest imaging have been published yet. The purpose of this systematic review is to investigate the AI-based CAD applications in pediatric radiology, their diagnostic performances and methods for their performance evaluation. A literature search with the use of electronic databases was conducted on 11 January 2023. Twenty-three articles that met the selection criteria were included. This review shows that the AI-based CAD could be applied in pediatric brain, respiratory, musculoskeletal, urologic and cardiac imaging, and especially for pneumonia detection. Most of the studies (93.3%, 14/15; 77.8%, 14/18; 73.3%, 11/15; 80.0%, 8/10; 66.6%, 2/3; 84.2%, 16/19; 80.0%, 8/10) reported model performances of at least 0.83 (area under receiver operating characteristic curve), 0.84 (sensitivity), 0.80 (specificity), 0.89 (positive predictive value), 0.63 (negative predictive value), 0.87 (accuracy), and 0.82 (F1 score), respectively. However, a range of methodological weaknesses (especially a lack of model external validation) are found in the included studies. In the future, more AI-based CAD studies in pediatric radiology with robust methodology should be conducted for convincing clinical centers to adopt CAD and realizing its benefits in a wider context.

1.5 vs 3 Tesla Magnetic Resonance Imaging: A Review of Favorite Clinical Applications for Both Field Strengths-Part 2.

The second part of this review deals with experiences in neuroradiological and pediatric examinations using modern magnetic resonance imaging systems with 1.5 T and 3 T, with special attention paid to experiences in pediatric cardiac imaging. In addition, whole-body examinations, which are widely used for diagnostic purposes in systemic diseases, are compared with respect to the image quality obtained in different body parts at both field strengths. A systematic overview of the technical differences at 1.5 T and 3 T has been presented in part 1 of this review, as well as several organ-based magnetic resonance imaging applications including musculoskeletal imaging, abdominal imaging, and prostate diagnostics.

Retrospective Study of Image Quality in Pediatric Cardiac Cine MRI

In pediatric cardiac cine magnetic resonance imaging (MRI), it must overcome several challenges including the patient's size and higher heart rate. The aim of this study was to retrospectively evaluate imaging optimization. Cardiac cine MRI data from 24 patients was analyzed (age range: 3 months-10 years, average age: 5 years, male/female: 11/13, R-R interval: 450±4 to 819±7 ms). About 11 cases out of 24 have good image quality. For small variations in the R-R interval and higher temporal resolution improved image quality with significant difference (P<0.05, Mann-Whitney U-test). In this study, values of temporal resolution <30 ms yielded good image quality for heart rates over 100 bpm. On the other hands, the factors dependent on the patient like heart rate and ejection fraction have no significant difference. The segmentation of data acquisition is more significant than recording small fields of view or thin slices for infantile and pediatric cardiac cine MRI. Similar to adult cases, variations in heart rate affect the image quality; however, we demonstrated that using segmentation of data acquisition results in improved image quality.

Recent Advances and Trends in Pediatric Cardiac Imaging.

Cardiac imaging is central to today's pediatric cardiology practice not only to diagnose structural congenital defects and delineate cardiac and extracardiac anatomy but also for determining the hemodynamic impact of the structural defects and acquired pediatric diseases. Not so long ago, clinicians had to heavily rely on angiography as the main cardiac imaging modality to visualize the heart. Particularly, the development of echocardiography in the 1970s and 1980s together with the development of magnetic resonance imaging (MRI) and computed tomography (CT) resulted in a non-invasive diagnostic revolution with diagnostic catheterization becoming obsolete apart for very specific indications. The continuous improvements in non-invasive imaging modalities allow an unprecedented level of understanding of cardiac morphology and function. Over the last few years, the specific roles of the three imaging modalities and their complementary roles in diagnosis and treatment have become well established resulting in a multimodality approach to specific congenital lesions. Recently, multimodality guidelines were published for postoperative tetralogy of Fallot and patients with transposition of the great arteries (Cohen et al. J Am Soc Echocardiogr. 2016;29(7):571-621, Valente et al. J Am Soc Echocardiogr. 2014;27(2):111-41). In this paper, we aim to highlight some of the most significant advances and highlight some emerging trends in pediatric cardiac imaging.

A clinical combined gadobutrol bolus and slow infusion protocol enabling angiography, inversion recovery whole heart, and late gadolinium enhancement imaging in a single study.

BackgroundThe use of gadolinium contrast agents in cardiovascular magnetic resonance is well-established and serves to improve both vascular imaging as well as enable late gadolinium enhancement (LGE) imaging for tissue characterization. Currently, gadofosveset trisodium, an intravascular contrast agent, combined with a three-dimensional inversion recovery balanced steady state free precession (3D IR bSSFP) sequence, is commonly used in pediatric cardiac imaging and yields excellent vascular imaging, but cannot be used for late gadolinium enhancement. Gadofosveset use remains limited in clinical practice, and manufacture was recently halted, thus an alternative is needed to allow 3D IR bSSFP and LGE in the same study.MethodsHere we propose a protocol to give a bolus of 0.1 mL/kg = 0.1 mmol/kg gadobutrol (GADAVIST/GADOVIST) for time-resolved magnetic resonance angiography (MRA). Subsequently, 0.1 mmol/kg is diluted up to 5 or 7.5 mL with saline and then loaded into intravenous tubing connected to the patient. A 0.5 mL short bolus is infused, then a slow infusion is given at 0.02 or 0.03 mL/s. Image navigated (iNAV) 3D IR bSSFP imaging is initiated 45–60 s after the initiation of the infusion, with a total image acquisition time of ~5 min. If necessary, LGE imaging using phase sensitive inversion recovery reconstruction (PSIR) is performed at 10 min after the infusion is initiated.ResultsWe have successfully performed the above protocol with good image quality on 10 patients with both time-resolved MRA and 3D IR bSSFP iNAV imaging. Our initial attempts to use pencil beam respiratory navigation failed due to signal labeling in the liver by the navigator. We have also performed 2D PSIR LGE successfully, with both LGE positive and LGE negative results.ConclusionA bolus of gadobutrol, followed later by a slow infusion, allows time-resolved MRA, 3D IR bSSFP using the iNAV navigation technique, and LGE imaging, all in a single study with a single contrast agent.

Improving Patient Throughput in a Busy Pediatric Mri Imaging Program Through a Nursing Coordinator

Background Pediatric cardiac MRIs form a small but critical part of MRI imaging at a busy pediatric cardiac imaging center. We had a higher than acceptable rate of no-show and wait times for scheduled cardiac MRIs, which was a source of patient and provider dissatisfaction in our institution. Previously, the process of scheduling a cardiac MRI was facilitated by a nonmedical provider. Dedicated nurse coordinator was added to the Pediatric Cardiac MRI scheduling team to provide a centralized and focused source for referral intakes and coordination of care.

Ferumoxytol as an off-label contrast agent in body 3T MR angiography: a pilot study in children.

Ferumoxytol is an ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle agent used to treat iron deficiency anemia in adults with chronic kidney disease. We aim to determine the feasibility of using ferumoxytol for clinical pediatric cardiac and vascular imaging. We retrospectively identified 23 consecutive children who underwent MRI with ferumoxytol (11 males; mean age: 7.4years, range: 3days-18years), yielding 12 abdominal MR angiography and 15 cardiac MRI studies. Medical records were reviewed for the clinical indication, ferumoxytol dose, injection rate, sedation and any complication. A two-reader consensus scored the images on a five-point scale for overall image quality and delineation of various anatomical structures. Signal-to-background ratios for abdominal aorta and inferior vena cava for abdominal cases and blood pool-myocardium contrast ratios for cardiac cases were calculated. The confidence intervals for obtaining a score of three or above for each image parameter were calculated by using adjusted Wald method. For abdominal MR angiography, average scores for overall image quality, as well as delineation of the hepatic artery, superior mesenteric artery, renal artery and veins were 4.5, 4.3, 4.3, 3.7 and 4.7, respectively. For cardiac exams, the average scores for overall image quality, systemic arteries, pulmonary arteries, pulmonary veins, valves and ventricles were 4.4, 4.6, 4.1, 4.8, 4.1 and 4.7, respectively. For all parameters, the lower bound for the proportion of cases to have a score of 3 or above was 65%. Signal-to-background ratios for aorta and abdominal veins averaged 86 +/- 74 and 86 +/- 77 for full-dose images, and 23 and 18 for half-dose images, respectively. Mean blood pool to myocardium contrast ratio was 3:3. Ferumoxytol can provide excellent image quality for pediatric body MR angiography/MR venography at a dose of 1.5 or 3mg Fe/kg. Further investigation should be directed toward understanding the lowest dose that can be administered.

Dynamic Contrast-enhanced MR Lymphangiography: Feasibility Study in Swine

To demonstrate the feasibility of dynamic four-dimensional ( 4D four-dimensional ) intranodal contrast material-enhanced magnetic resonance (MR) lymphangiography with inguinal lymph node injection of gadopentetate dimeglumine. All procedures were performed in accordance with the guidelines on the use of animals in research and were approved by the animal care and use committee. Five swine underwent nonenhanced MR lymphangiography with a heavily T2-weighted MR sequence, bilateral inguinal lymph node injection of 2 mL of undiluted gadopentetate at a rate of 1 mL/min, and 60 minutes of MR imaging with T1-weighted high-spatial- and high-temporal-resolution MR angiography. Images were reviewed by a radiologist with expertise in lymphatic imaging and a pediatric cardiac MR imaging specialist for visualization of the thoracic duct ( TD thoracic duct ). Categorical variables were compared by using the exact conditional McNemar test. A difference with a P value less than .05 was considered significant. The TD thoracic duct was visualized in three of the five animals (60%) on T2-weighted images. In contrast, the TD thoracic duct was visualized in all five of the animals (100%) after contrast agent injection (P = .25). The median time for flow of the contrast agent through the lymphatic system to the TD thoracic duct outlet was 244 seconds (range, 201-387 seconds). Enhancement was seen in the TD thoracic duct up to 1 hour after injection. All animals survived without any complications. Dynamic 4D four-dimensional contrast-enhanced MR lymphangiography with intranodal injection of gadopentetate dimeglumine is feasible, produces good images of the central lymphatic system, and demonstrates the time course of flow of contrast agent up the central lymphatic ducts. On the basis of the results of this initial animal experiment, it appears that dynamic 4D four-dimensional contrast-enhanced MR lymphangiography is potentially feasible and safe with commercially available contrast agents.

Process improvement decreases no show rates for pediatric cardiac MR imaging with anesthesia

Background Coordination of pediatric imaging and anesthesia is a complex logistical challenge involving anesthesiologists, nurses, anesthetists, nurse practitioners, PACU nurses, radiologists, technologists and notwithstanding schedulers and receptionists. Parents often can be stressed, due to the child’s NPO status and/or physical condition. Driving to an unfamiliar hospital and transportation difficulties can lead to an appointment no-show. We identified a high noshow rate in the formation of a pediatric cardiac imaging program and instituted process improvement changes to improve attendance in an academic center with a predominately rural population.

Liver and heart MR relaxometry in iron loading: Reproducibility of three methods

To compare the derived T2* values and reproducibility of three methods used to assess iron-loading in heart and liver. In 23 pediatric patients, liver and cardiac gradient-echo imaging datasets (within-exam repeated sequence pairs) were evaluated. Data analyses compared derived relaxation values (average of pairs) and coefficient of variation (reproducibility of pairs). T2* values showed differences across methods, with pixel-wise mean > average fit > pixel-wise median. Coefficient of variation was found to be lower (better) with pixel-wise median and average fit methods compared to the pixel-wise mean technique. Maximum coefficient of variation values were lowest for the pixel-wise median approach in both the heart and liver. Differences in derived T2* values between methods must be considered when comparing values to established magnetic resonance imaging (MRI)-biopsy formulas. The pixel-wise median and average fit methods demonstrate substantial benefits in reproducibility compared to the pixel-wise mean method. Since minimal variation in measurement is critical for patient care, median processing of relaxometry data may be preferable in both tissue types.

Characterization of Cardiac Tumors in Children by Cardiovascular Magnetic Resonance Imaging: A Multicenter Experience

The aim of this study was to report the results of an international multicenter experience of cardiac magnetic resonance imaging (MRI) evaluation of cardiac tumors in children, each with histology correlation or a diagnosis of tuberous sclerosis, and to determine which characteristics are predictive of tumor type. Individual centers have relatively little experience with diagnostic imaging of cardiac tumors in children, because of their low prevalence. The accuracy of cardiac MRI diagnosis on the basis of a pre-defined set of criteria has not been tested. An international group of pediatric cardiac imaging centers was solicited for case contribution. Inclusion criteria comprised: 1) age at diagnosis ≤18 years; 2) cardiac MRI evaluation of cardiac tumor; and 3) histologic diagnosis or diagnosis of tuberous sclerosis. Data from the cardiac MRI images were analyzed for mass characteristics. On the basis of pre-defined cardiac MRI criteria derived from published data, 3 blinded investigators determined tumor type, and their consensus diagnoses were compared with histologic diagnoses. Cases (n = 78) submitted from 15 centers in 4 countries had the following diagnoses: fibroma (n = 30), rhabdomyoma (n = 14), malignant tumor (n = 12), hemangioma (n = 9), thrombus (n = 4), myxoma (n = 3), teratoma (n = 2), and paraganglioma, pericardial cyst, Purkinje cell tumor, and papillary fibroelastoma (n = 1, each). Reviewers who were blinded to the histologic diagnoses correctly diagnosed 97% of the cases but included a differential diagnosis in 42%. Better image quality grade and more complete examination were associated with higher diagnostic accuracy. Cardiac MRI can predict the likely tumor type in the majority of children with a cardiac mass. A comprehensive imaging protocol is essential for accurate diagnosis. However, histologic diagnosis remains the gold standard, and in some cases malignancy cannot be definitively excluded on the basis of cardiac MRI images alone.

Three-dimensional echocardiography in congenital heart disease

Three-dimensional echocardiography (3DE) is a new, rapidly evolving modality for pediatric cardiac imaging. Important technological advances have heralded an era in which practical 3DE scanning is becoming a mainstream modality. This article reviews the applicability of 3DE to congenital heart defects to visualize anatomy in a spectrum of defects ranging from atrioventricular septal defects to mitral valve abnormalities and Ebstein’s anomaly. It illustrates the use of 3DE color flow to obtain echocardiographic angiograms and reviews the state of the science in quantitating right and left ventricular volumetrics. In addition, the review provides examples of novel applications including 3DE transesophageal echocardiography and image-guided interventions.

What is new in pediatric cardiac imaging?

Cardiac imaging has had significant influence on the science and practice of pediatric cardiology. Especially the development and improvements made in noninasive imaging techniques, like echocardiography and cardiac magnetic resonance imaging (MRI), have been extremely important. Technical advancements in the field of medical imaging are quickly being made. This review will focus on some of the important evolutions in pediatric cardiac imaging. Techniques such as intracardiac echocardiography, 3D echocardiography, and tissue Doppler imaging are relatively new echocardiographic techniques, which further optimize the anatomical and functional aspects of congenital heart disease. Also, the current standing of cardiac MRI and cardiac computerized tomography will be discussed. Finally, the recent European efforts to organize training and accreditation in pediatric echocardiography are highlighted.

Pediatric cardiac imaging: the beat goes on!

The publication of the paper “The accuracy of chest radiographs in the detection of congenital heart disease and in the diagnosis of specific congenital cardiac lesions” [1] provides an opportunity for me to reflect on my career as a pediatric cardiac imager, on past teaching strategies in cardiac imaging, and to comment on the current and future opportunities. I welcome this re-evaluation of cardiac imaging, and the new horizons. Nearly 40 years ago, prior to echocardiography, the gold standard for recognizing children with congenital heart disease consisted of findings on physical examination and a chest radiograph. Traditionally, the radiologist tried to decide based on the chest radiograph whether the infant or child had congenital or acquired heart disease and to suggest a differential diagnosis. Each new generation of residents would learn the list of congenital heart lesions associated with increased, decreased and normal flow, and after asking whether the patient was cyanotic or acyanotic, they would proceed with a list of lesions associated with the flow pattern. Despite the advancement of non-invasive modalities such as echocardiography, CT, and MRI, the approach to teaching and educational programs was based on the assessment of pulmonary flow. Retrospectively, this may have been a flawed approach to cardiac imaging and has resulted in many radiologists not understanding basic physiology and anatomy of the heart.

Cardiac screening examination of the fetus: guidelines for performing the ‘basic’ and ‘extended basic’ cardiac scan

Cardiac screening examination of the fetus: guidelines for performing the ‘basic’ and ‘extended basic’ cardiac scan

Isolated Noncompaction of the Myocardium

To the Editor: Isolated noncompaction of the ventricular myocardium is a rare congenital disorder. We have reported elsewhere that the incidence of this unique cardiomyopathy is 0.05 percent in adults.1 In the report of the 1995 World Health Organization–International Society and Federation of Cardiology task force on the definition and classification of cardiomyopathies, noncompacted myocardium has been categorized as unclassified cardiomyopathy.2 Noncompaction refers to the arrest of compaction of the loosely interwoven meshwork of myocardial fibers during embryogenesis.3 The loose meshwork becomes more compact toward the epicardial surface and condenses to a compact wall, and the intertrabecular recesses communicating with . . .

High-resolution cardiac imaging using an interleaved 3D double slab technique

A three-dimensional (3D) gradient-echo sequence with interleaved double-slab excitation was developed and optimized for the requirements in pediatric cardiac imaging. For this purpose high contrast between blood and myocardium signal should be obtained without the use of contrast agents. An acceptable measuring time for a large region examined with high spatial resolution should be achieved as well, especially with regard to the small structures of the heart and vessels of infants. The presented approach works with gradient moment nulling and a short echo time of 5.5 ms resulting in generally high signal intensity and only minor signal losses due to turbulent flow. The sequence allows simultaneous ECG-gated recording of two separately excited slabs with small thickness (10 mm) and with a distance of several centimeters between them. Thus, common effects of presaturation in 3D imaging can be avoided, although a relatively short measuring time is achievable. In order to get a 3D data set with good signal homogeneity of blood and of the other structures across a large volume of interest several double-slab measurements with suitable positions must be performed. The latter aspect is especially important for postprocessing techniques as multiple planar reconstruction and maximum intensity projection. Examples of applications of the new technique and appropriately postprocessed images are presented allowing demonstration even of subtle cardiac malformations.

Clinical applications of a pressurized xenon wire chamber gamma camera utilizing the short lived agent 178Ta

A pressurized xenon wire chamber camera has been developed for applications in nuclear medicine. The device employs a high speed delay-line readout and digital processing system providing a peak count rate of 850 000 cps, spatial resolution of 2.5 mm and highly uniform imaging characteristics. A short-lived generator produced radionuclide, 178Ta, having an emission energy of 55–65 keV has also been developed. It provides greatly reduced radiation dosimetry compared with any commercial isotope in current use and is imaged very effectively with the wire chamber camera. Performance of this camera and isotope for first-pass radionuclide assessment of cardiac function compares favorably with the accepted standard of this technique, the multicrystal gamma camera and 99mTc. Currently ongoing studies in exercise cardiac assessment, bedside imaging in myocardial infarction patients and pediatric cardiac imaging, point the way to unique applications of this technology in cardiology.

Pediatric cardiac imaging. By William F. Friedman and Charles B. Higgins. Philadelphia, WB Saunders, 1984

Pediatric cardiac imaging. By William F. Friedman and Charles B. Higgins. Philadelphia, WB Saunders, 1984