Trends in cardiac CT utilization for patients with pediatric and congenital heart disease: A multicenter survey study

BACKGROUND

The use of cardiac CT (CCT) has increased dramatically in recent years among patients with pediatric and congenital heart disease (CHD), but little is known about trends and practice pattern variation in CCT utilization for this population among centers.

METHODS

A 21-item survey was created to assess CCT utilization in the pediatric/CHD population in calendar years 2011 and 2021. The survey was sent to all non-invasive cardiac imaging directors of pediatric cardiology centers in North America in September 2022.

RESULTS

Forty-one centers completed the survey. In 2021, 98% of centers performed CCT in pediatric and CHD patients (vs. 73% in 2011), and 61% of centers performed >100 CCTs annually (vs. 5% in 2011). While 62% of centers in 2021 utilized dual-source technology for high-pitch helical acquisition, 15% of centers reported primarily performing CCT on a 64-slice scanner. Anesthesia utilization, use of medications for heart rate control, and type of subspecialty training for physicians interpreting CCT varied widely among centers. 50% of centers reported barriers to CCT performance, with the most commonly cited concerns being radiation exposure, the need for anesthesia, and limited CT scan staffing or machine access. 37% (11/30) of centers with a pediatric cardiology fellowship program offer no clinical or didactic CCT training for categorical fellows.

CONCLUSION

While CCT usage in the CHD/pediatric population has risen significantly in the past decade, there is broad center variability in CCT acquisition techniques, staffing, workflow, and utilization. Potential areas for improvement include expanding CT scanner access and staffing, formal CCT education for pediatric cardiology fellows, and increasing utilization of existing technological advances.

Proposed competencies for the performance of cardiovascular computed tomography in pediatric and adult congenital heart disease

Cardiovascular computed tomography (CCT) is rated appropriate by published guidelines for the initial evaluation and follow up of congenital heart disease (CHD) and is an essential modality in cardiac imaging programs for patients of all ages. However, no recommended core competencies exist to guide CCT in CHD imaging training pathways, curricula development, or establishment of a more formal educational platform. To fill this gap, a group of experienced congenital cardiac imagers, intentionally inclusive of adult and pediatric cardiologists and radiologists, was formed to propose core competencies fundamental to the expert-level performance of CCT in pediatric acquired and congenital heart disease and adult CHD. The 2020 SCCT Guideline for Training Cardiology and Radiology Trainees as Independent Practitioners (Level II) and Advanced Practitioners (Level III) in Cardiovascular Computed Tomography (1) for adult imaging were used as a framework to define pediatric and CHD-specific competencies. Established competencies will be immediately relevant for advanced cardiac imaging fellowships in both cardiology and radiology training pathways. Proposed future steps include radiology and cardiology society collaboration to establish provider certification levels, training case-volume recommendations, and continuing medical education (CME) requirements for expert-level performance of CCT in pediatric and adult CHD.

The journal of cardiovascular computed tomography: A year in review: 2022

This review aims to summarize key articles published in the Journal of Cardiovascular Computed Tomography (JCCT) in 2022, focusing on those that had the most scientific and educational impact. The JCCT continues to expand; the number of submissions, published manuscripts, cited articles, article downloads, social media presence, and impact factor continues to grow. The articles selected by the Editorial Board of the JCCT in this review highlight the role of cardiovascular computed tomography (CCT) to detect subclinical atherosclerosis, assess the functional relevance of stenoses, and plan invasive coronary and valve procedures. A section is dedicated to CCT in infants and other patients with congenital heart disease, in women, and to the importance of training in CT. In addition, we highlight key consensus documents and guidelines published in JCCT last year. The Journal values the tremendous work by authors, reviewers, and editors to accomplish these contributions.

The Journal of cardiovascular computed tomography: A year in review 2021

This review aims to summarize original articles published in the Journal of Cardiovascular Computed Tomography (JCCT) for the year 2021, focusing on those that had the most scientific and educational impact. The JCCT continues to expand; the number of submissions, published manuscripts, cited articles, article downloads, social media presence, and impact factor continues to increase. The articles selected by the Editorial Board of the JCCT in this review focus on coronary artery disease, coronary physiology, structural heart disease, and technical advances in cardiovascular CT. In addition, we highlight key consensus documents and guidelines published in the Journal in 2021. The Journal recognizes the tremendous work done by each author and reviewer this year - thank you.

OS08.6.A Glioblastoma treatment response machine learning monitoring biomarkers: a systematic review and meta-analysis

BACKGROUND

The aim of the systematic review was to assess recently published studies on diagnostic test accuracy of glioblastoma treatment response monitoring biomarkers in adults, developed through machine learning (ML).

MATERIAL AND METHODS

PRISMA methodology was followed. Articles published 09/2018-01/2021 (since previous reviews) were searched for using MEDLINE, EMBASE, and the Cochrane Register by two reviewers independently. Included study participants were adult patients with high grade glioma who had undergone standard treatment (maximal resection, radiotherapy with concomitant and adjuvant temozolomide) and subsequently underwent follow-up imaging to determine treatment response status (specifically, distinguishing progression/recurrence from progression/recurrence mimics - the target condition). Risk of bias and applicability was assessed with QUADAS 2. A third reviewer arbitrated any discrepancy. Contingency tables were created for hold-out test sets and recall, specificity, precision, F1-score, balanced accuracy calculated. A meta-analysis was performed using a bivariate model for recall, false positive rate and area-under the receiver operator characteristic curve (AUC).

RESULTS

Eighteen studies were included with 1335 patients in training sets and 384 in test sets. To determine whether there was progression or a mimic, the reference standard combination of follow-up imaging and histopathology at re-operation was applied in 67% (13/18) of studies. The small numbers of patient included in studies, the high risk of bias and concerns of applicability in the study designs (particularly in relation to the reference standard and patient selection due to confounding), and the low level of evidence, suggest that limited conclusions can be drawn from the data. Ten studies (10/18, 56%) had internal or external hold-out test set data that could be included in a meta-analysis of monitoring biomarker studies. The pooled sensitivity was 0.77 (0.65–0.86). The pooled false positive rate (1-specificity) was 0.35 (0.25–0.47). The summary point estimate for the AUC was 0.77.

CONCLUSION

There is likely good diagnostic performance of machine learning models that use MRI features to distinguish between progression and mimics. The diagnostic performance of ML using implicit features did not appear to be superior to ML using explicit features. There are a range of ML-based solutions poised to become treatment response monitoring biomarkers for glioblastoma. To achieve this, the development and validation of ML models require large, well-annotated datasets where the potential for confounding in the study design has been carefully considered. Therefore, multidisciplinary efforts and multicentre collaborations are necessary.

Contemporary Outcomes in Tetralogy of Fallot With Absent Pulmonary Valve After Fetal Diagnosis

Background

Tetralogy of Fallot with absent pulmonary valve is associated with high mortality, but it remains difficult to predict outcomes prenatally. We aimed to identify risk factors for mortality in a large multicenter cohort.

Methods and Results

Fetal echocardiograms and clinical data from 19 centers over a 10‐year period were collected. Primary outcome measures included fetal demise and overall mortality. Of 100 fetuses, pregnancy termination/postnatal nonintervention was elected in 22. Of 78 with intention to treat, 7 (9%) died in utero and 21 (27%) died postnatally. With median follow‐up of 32.9 months, no deaths occurred after 13 months. Of 80 fetuses with genetic testing, 46% had chromosomal abnormalities, with 22q11.2 deletion in 35%. On last fetal echocardiogram, at a median of 34.6 weeks, left ventricular dysfunction independently predicted fetal demise (odds ratio [OR], 7.4; 95% CI 1.3, 43.0; P=0.026). Right ventricular dysfunction independently predicted overall mortality in multivariate analysis (OR, 7.9; 95% CI 2.1–30.0; P=0.002). Earlier gestational age at delivery, mediastinal shift, left ventricular/right ventricular dilation, left ventricular dysfunction, tricuspid regurgitation, and Doppler abnormalities were associated with fetal and postnatal mortality, although few tended to progress throughout gestation on serial evaluation. Pulmonary artery diameters did not correlate with outcomes.

Conclusions

Perinatal mortality in tetralogy of Fallot with absent pulmonary valve remains high, with overall survival of 64% in fetuses with intention to treat. Right ventricular dysfunction independently predicts overall mortality. Left ventricular dysfunction predicts fetal mortality and may influence prenatal management and delivery planning. Mediastinal shift may reflect secondary effects of airway obstruction and abnormal lung development and is associated with increased mortality.

Impact of Socioeconomic Status, Race and Ethnicity, and Geography on Prenatal Detection of Hypoplastic Left Heart Syndrome and Transposition of the Great Arteries

BACKGROUND

Prenatal detection (PND) has benefits for infants with hypoplastic left heart syndrome (HLHS) and transposition of the great arteries (TGA), but associations between sociodemographic and geographic factors with PND have not been sufficiently explored. This study evaluated whether socioeconomic quartile (SEQ), public insurance, race and ethnicity, rural residence, and distance of residence (distance and driving time from a cardiac surgical center) are associated with the PND or timing of PND, with a secondary aim to analyze differences between the United States and Canada.

METHODS

In this retrospective cohort study, fetuses and infants <2 months of age with HLHS or TGA admitted between 2012 and 2016 to participating Fetal Heart Society Research Collaborative institutions in the United States and Canada were included. SEQ, rural residence, and distance of residence were derived using maternal census tract from the maternal address at first visit. Subjects were assigned a SEQ z score using the neighborhood summary score or Canadian Chan index and separated into quartiles. Insurance type and self-reported race and ethnicity were obtained from medical charts. We evaluated associations among SEQ, insurance type, race and ethnicity, rural residence, and distance of residence with PND of HLHS and TGA (aggregate and individually) using bivariate analysis with adjusted associations for confounding variables and cluster analysis for centers.

RESULTS

Data on 1862 subjects (HLHS: n=1171, 92% PND; TGA: n=691, 58% PND) were submitted by 21 centers (19 in the United States). In the United States, lower SEQ was associated with lower PND in HLHS and TGA, with the strongest association in the lower SEQ of pregnancies with fetal TGA (quartile 1, 0.78 [95% CI, 0.64-0.85], quartile 2, 0.77 [95% CI, 0.64-0.93], quartile 3, 0.83 [95% CI, 0.69-1.00], quartile 4, reference). Hispanic ethnicity (relative risk, 0.85 [95% CI, 0.72-0.99]) and rural residence (relative risk, 0.78 [95% CI, 0.64-0.95]) were also associated with lower PND in TGA. Lower SEQ was associated with later PND overall; in the United States, rural residence and public insurance were also associated with later PND.

CONCLUSIONS

We demonstrate that lower SEQ, Hispanic ethnicity, and rural residence are associated with decreased PND for TGA, with lower SEQ also being associated with decreased PND for HLHS. Future work to increase PND should be considered in these specific populations.

Evaluation of self-calibrated non-linear phase-contrast correction in pediatric and congenital cardiovascular magnetic resonance imaging

BACKGROUND

The need for background error correction in phase-contrast flow analysis has historically posed a challenge in cardiac magnetic resonance (MR) imaging. While previous studies have shown that phantom correction improves flow measurements, it impedes scanner workflow.

OBJECTIVE

To evaluate the efficacy of self-calibrated non-linear phase-contrast correction on flows in pediatric and congenital cardiac MR compared to phantom correction as the standard.

MATERIALS AND METHODS

We retrospectively identified children who had great-vessel phase-contrast and static phantom sequences acquired between January 2015 and June 2015. We applied a novel correction method to each phase-contrast sequence post hoc. Uncorrected, non-linear, and phantom-corrected flows were compared using intraclass correlation. We used paired t-tests to compare how closely non-linear and uncorrected flows approximated phantom-corrected flows. In children without intra- or extracardiac shunts or significant semilunar valvular regurgitation, we used paired t-tests to compare how closely the uncorrected pulmonary-to-systemic flow ratio (Qp:Qs) and non-linear Qp:Qs approximated phantom-corrected Qp:Qs.

RESULTS

We included 211 diagnostic-quality phase-contrast sequences (93 aorta, 74 main pulmonary artery [MPA], 21 left pulmonary artery [LPA], 23 right pulmonary artery [RPA]) from 108 children (median age 15 years, interquartile range 11-18 years). Intraclass correlation showed strong agreement between non-linear and phantom-corrected flow measurements but also between uncorrected and phantom-corrected flow measurements. Non-linear flow measurements did not more closely approximate phantom-corrected measurements than did uncorrected measurements for any vessel. In 39 children without significant shunting or regurgitation, mean non-linear Qp:Qs (1.07; 95% confidence interval [CI] = 1.01, 1.13) was no closer than mean uncorrected Qp:Qs (1.06; 95% CI = 1.00, 1.13) to mean phantom-corrected Qp:Qs (1.02; 95% CI = 0.98, 1.06).

CONCLUSION

Despite strong agreement between self-calibrated non-linear and phantom correction, cardiac flows and shunt calculations with non-linear correction were no closer to phantom-corrected measurements than those without background correction. However, phantom-corrected flows also demonstrated minimal differences from uncorrected flows. These findings suggest that in the current era, more accurate phase-contrast flow measurements might limit the need for background correction. Further investigation of the clinical impact and optimal methods of background correction in the pediatric and congenital cardiac population is needed.

Myocardial strain abnormalities in fetuses with pulmonary atresia and intact ventricular septum

OBJECTIVES

Global and regional myocardial deformation have not been well described in fetuses with pulmonary atresia and intact ventricular septum (PA/IVS). Speckle-tracking echocardiography (STE), an angle-independent technique for assessing global and regional strain, may be a more sensitive way of determining ventricular systolic dysfunction compared with traditional 2D echocardiography. The aim of this study was to assess myocardial deformation in fetuses with PA/IVS compared with control fetuses and to determine if, in fetuses with PA/IVS, strain differs between those with and those without right ventricle-dependent coronary circulation (RVDCC).

METHODS

This was a retrospective analysis of fetuses with PA/IVS examined at two medical centers between June 2005 and October 2017. Left ventricular (LV) and right ventricular (RV) regional and global longitudinal strain (GLS) and strain rate were obtained using STE, and comparisons were made between fetuses with PA/IVS and gestational age (GA)-matched controls. Postnatal outcome was assessed, including the presence of RVDCC.

RESULTS

Fifty-seven fetuses with PA/IVS and 57 controls were analyzed at a mean GA of 26.5 ± 5 weeks. LV-GLS was significantly decreased in fetuses with PA/IVS compared with controls (-17.4 ± 1.7% vs -23.7 ± 2.0%, P < 0.001). LV strain rate was also significantly decreased (-1.01 ± 0.21/s vs -1.42 ± 0.20/s, P < 0.001). Fetuses with PA/IVS had decreased strain in all segments. Similarly, RV strain was significantly decreased in fetuses with PA/IVS (-11.6 ± 3.8% vs -24.6 ± 2.5%, P < 0.0001). Thirty-six patients had postnatal cardiac catheterization performed to define coronary anatomy; 10 fetuses had RVDCC. Fetuses with RVDCC had decreased LV strain compared with those without (-15.8 ± 1.2% vs -17.9 ± 1.7%, P = 0.009). RV strain was also decreased in fetuses with RVDCC vs those without (-7.0 ± 2.9% vs -12.1 ± 3.2%, P = 0.0004).

CONCLUSIONS

Fetuses with PA/IVS have decreased global and regional LV and RV strain compared with controls. The finding of decreased LV strain may be due to altered ventricular mechanics in the context of a hypertensive right ventricle and/or abnormal coronary perfusion. Moreover, fetuses that were found to have RVDCC postnatally had decreased LV and RV strain compared with those that did not. These results encourage further investigation to assess whether fetal ventricular strain could be a prenatal predictor of RVDCC. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

3D Printing and Heart Failure: The Present and the Future

Advanced imaging modalities provide essential anatomic and spatial information in patients with complex heart disease. Two-dimensional imaging can be limited in the extent to which true 3-dimensional (3D) relationships are represented. The application of 3D printing technology has increased the creation of physical models that overcomes the limitations of a 2D screen. Many groups have reported the use of 3D printing for preprocedural planning in patients with different causes of heart failure. This paper reviews the innovative applications of this technique to provide patient-specific models to improve patient care.

Outcomes of Surgical Repair of Complex D-Transposition of the Great Arteries

BACKGROUND

D-transposition of the great arteries (TGA) or TGA-type double outlet right ventricle (DORV) with ventricular septal defect (VSD) and left ventricular outflow tract obstruction (LVOTO) may be treated with the arterial switch operation (ASO), Rastelli, Réparation à l'Etage Ventriculaire (REV), or Nikaidoh procedures. We evaluated midterm results of these techniques.

METHODS

We retrospectively reviewed 42 cases of anatomic repair from 2005 to 2014 at our institution for TGA (n = 29) or TGA-type DORV (n = 13) with VSD and LVOTO. We analyzed outcomes (mortality, reoperation, residual/recurrent LVOT peak gradient ≥20 mm Hg, right ventricular outflow tract [RVOT] peak gradient ≥40 mm Hg) and performed a risk analysis. Mean follow-up was 5.77 ± 3.08 years.

RESULTS

Seventeen (40.5%) patients had an ASO with (n = 4) or without (n = 13) LVOTO resection. The Rastelli, REV, and Nikaidoh procedures were used in 14 (33%), 5 (12%), and 6 (14%) patients, respectively. There were no mortalities or moderate aortic insufficiency at last follow-up. Three (9%) patients developed LVOT gradient ≥20 mm Hg, while nine (21.4%) patients had RVOT obstruction. Reoperations included RVOT/pulmonary artery reoperation (n = 10; 23.8%) and LVOT reoperation (n = 1; 2.5%). Freedom from reoperation was 84% ± 6% and 75% ± 9% at one and three years, respectively, for the entire cohort with no differences between groups by type of operation (log-rank P = .64). The Nikaidoh procedure compared favorably to all other techniques in terms of reoperation (n = 0/6; 0% vs n = 13/36; 36%; P = .08).

CONCLUSIONS

Midterm outcomes after anatomic repair for TGA or TGA-type DORV with LVOTO and VSD are excellent but vary by surgical technique. The Nikaidoh procedure seems to compare favorably to the other techniques.

Significance of Intraoperative Revision During Arterial Switch Operation in the Current Era

BACKGROUND

Arterial switch operation (ASO) is a relatively safe operation nowadays. We hypothesize that intraoperative revision for coronary malperfusion still plays an important role during ASO in the current era.

METHODS

From January 2005 to May 2016, 244 patients underwent ASO. Medical records were reviewed and the details of intraoperative revision were described. Morbidity and mortality were compared in patients with/without intraoperative revision. Factors related to the need for intraoperative revision were analyzed.

RESULTS

Seventeen (7%) patients needed intraoperative revision. As a technique for intraoperative revision, revision of a coronary button was performed in eight patients and revision of the main pulmonary artery anastomosis to relieve compression on the coronary artery was performed in five patients. Factors related to intraoperative revision were body weight at surgery ( P = .051), eccentric position of the coronary ostium ( P = .01), single coronary artery system ( P = .03), and intramural coronary artery ( P = .003). The commonest coronary artery origin and branching pattern was not protective against the need for intraoperative revision ( P = .43). Discharge mortality was 2% overall: 2 of 17 with intraoperative revision versus 3 of 238 without it ( P = .04). Patients who underwent intraoperative revision had longer postoperative hospitalization ( P = .003).

CONCLUSION

The need for intraoperative revision was related to eccentric coronary ostium, single coronary artery, and intramural coronary artery. Although the need for intraoperative revision correlated with higher mortality and morbidity, prompt intraoperative revision also likely contributed to our good results after ASO.

Patients with anomalous aortic origin of the coronary artery remain at risk after surgical repair

OBJECTIVES

Anomalous aortic origin of a coronary artery (AAOCA) from the opposite sinus of Valsalva is a rare cardiac anomaly associated with sudden cardiac death (SCD). Single-center studies describe surgical repair as safe, although medium- and long-term effects on symptoms and risk of SCD remain unknown. We sought to describe outcomes of surgical repair of AAOCA.

METHODS

We reviewed institutional records for patients who underwent AAOCA repair, from 2001 to 2016, at 2 affiliated institutions. Patients with associated heart disease were excluded.

RESULTS

In total, 60 patients underwent AAOCA repair. Half of the patients (n = 30) had an anomalous left coronary artery arising from the right sinus of Valsalva and half had an anomalous right. Median age at surgery was 15.4 years (interquartile range, 11.9-17.9 years; range, 4 months to 68 years). The most common presenting symptoms were chest pain (n = 38; 63%) and shortness of breath (n = 17; 28%); aborted SCD was the presenting symptom in 4 patients (7%). Follow-up data were available for 54 patients (90%) over a median of 1.6 years. Of 53 patients with symptoms at presentation, 34 (64%) had complete resolution postoperatively. Postoperative mild or greater aortic insufficiency was present in 8 patients (17%) and moderate supravalvar aortic stenosis in 1 (2%). One patient required aortic valve replacement for aortic insufficiency. Two patients required reoperation for coronary stenosis at 3 months and 6 years postoperatively.

CONCLUSIONS

Surgical repair of AAOCA is generally safe and adverse events are rare. Restenosis, and even sudden cardiac events, can occur and long-term surveillance is critical. Multi-institutional collaboration is vital to identify at-risk subpopulations and refine current recommendations for long-term management.

Radiation dose management for pediatric cardiac computed tomography: a report from the Image Gently 'Have-A-Heart' campaign

Children with congenital or acquired heart disease can be exposed to relatively high lifetime cumulative doses of ionizing radiation from necessary medical imaging procedures including radiography, fluoroscopic procedures including diagnostic and interventional cardiac catheterizations, electrophysiology examinations, cardiac computed tomography (CT) studies, and nuclear cardiology examinations. Despite the clinical necessity of these imaging studies, the related ionizing radiation exposure could pose an increased lifetime attributable cancer risk. The Image Gently "Have-A-Heart" campaign is promoting the appropriate use of medical imaging studies in children with congenital or acquired heart disease while minimizing radiation exposure. The focus of this manuscript is to provide a comprehensive review of radiation dose management and CT performance in children with congenital or acquired heart disease.

Cardiac-Specific Conversion Factors to Estimate Radiation Effective Dose From Dose-Length Product in Computed Tomography

OBJECTIVES

This study sought to determine updated conversion factors (k-factors) that would enable accurate estimation of radiation effective dose (ED) for coronary computed tomography angiography (CTA) and calcium scoring performed on 12 contemporary scanner models and current clinical cardiac protocols and to compare these methods to the standard chest k-factor of 0.014 mSv·mGy-1cm-1.

BACKGROUND

Accurate estimation of ED from cardiac CT scans is essential to meaningfully compare the benefits and risks of different cardiac imaging strategies and optimize test and protocol selection. Presently, ED from cardiac CT is generally estimated by multiplying a scanner-reported parameter, the dose-length product, by a k-factor which was determined for noncardiac chest CT, using single-slice scanners and a superseded definition of ED.

METHODS

Metal-oxide-semiconductor field-effect transistor radiation detectors were positioned in organs of anthropomorphic phantoms, which were scanned using all cardiac protocols, 120 clinical protocols in total, on 12 CT scanners representing the spectrum of scanners from 5 manufacturers (GE, Hitachi, Philips, Siemens, Toshiba). Organ doses were determined for each protocol, and ED was calculated as defined in International Commission on Radiological Protection Publication 103. Effective doses and scanner-reported dose-length products were used to determine k-factors for each scanner model and protocol.

RESULTS

k-Factors averaged 0.026 mSv·mGy-1cm-1 (95% confidence interval: 0.0258 to 0.0266) and ranged between 0.020 and 0.035 mSv·mGy-1cm-1. The standard chest k-factor underestimates ED by an average of 46%, ranging from 30% to 60%, depending on scanner, mode, and tube potential. Factors were higher for prospective axial versus retrospective helical scan modes, calcium scoring versus coronary CTA, and higher (100 to 120 kV) versus lower (80 kV) tube potential and varied among scanner models (range of average k-factors: 0.0229 to 0.0277 mSv·mGy-1cm-1).

CONCLUSIONS

Cardiac k-factors for all scanners and protocols are considerably higher than the k-factor currently used to estimate ED of cardiac CT studies, suggesting that radiation doses from cardiac CT have been significantly and systematically underestimated. Using cardiac-specific factors can more accurately inform the benefit-risk calculus of cardiac-imaging strategies.

Estimating Effective Dose of Radiation From Pediatric Cardiac CT Angiography Using a 64-MDCT Scanner: New Conversion Factors Relating Dose-Length Product to Effective Dose

OBJECTIVE

The purpose of this study is to determine the conversion factors that enable accurate estimation of the effective dose (ED) used for cardiac 64-MDCT angiography performed for children.

MATERIALS AND METHODS

Anthropomorphic phantoms representative of 1- and 10-year-old children, with 50 metal oxide semiconductor field-effect transistor dosimeters placed in organs, underwent scanning performed using a 64-MDCT scanner with different routine clinical cardiac scan modes and x-ray tube potentials. Organ doses were used to calculate the ED on the basis of weighting factors published in 1991 in International Commission on Radiological Protection (ICRP) publication 60 and in 2007 in ICRP publication 103. The EDs and the scanner-reported dose-length products were used to determine conversion factors for each scan mode. The effect of infant heart rate on the ED and the conversion factors was also assessed.

RESULTS

The mean conversion factors calculated using the current definition of ED that appeared in ICRP publication 103 were as follows: 0.099 mSv · mGy-1 · cm-1, for the 1-year-old phantom, and 0.049 mSv · mGy-1 · cm-1, for the 10-year-old phantom. These conversion factors were a mean of 37% higher than the corresponding conversion factors calculated using the older definition of ED that appeared in ICRP publication 60. Varying the heart rate did not influence the ED or the conversion factors.

CONCLUSION

Conversion factors determined using the definition of ED in ICRP publication 103 and cardiac, rather than chest, scan coverage suggest that the radiation doses that children receive from cardiac CT performed using a contemporary 64-MDCT scanner are higher than the radiation doses previously reported when older chest conversion factors were used. Additional up-to-date pediatric cardiac CT conversion factors are required for use with other contemporary CT scanners and patients of different age ranges.

Myocardial strain can be measured from first trimester fetal echocardiography using velocity vector imaging

OBJECTIVES

Alterations in myocardial strain can identify cardiac dysfunction and can be measured in the mid-gestation fetus. This study evaluates feasibility of strain measurements in early fetuses and establishes normal early fetal strain values.

METHODS

Normal fetal echocardiograms were reviewed for image adequacy for strain measurements in 12- to 14-week gestation fetuses. Two readers performed independent strain measurements. Values were compared with data from 40 normal second trimester fetuses.

RESULTS

Strain evaluation could be attempted in 36 of 53 (68%) of first trimester echocardiograms (mean gestation 13.4 weeks); excessive motion or inadequate imaging planes precluded tracking analysis in the remainder. Strain measurements were feasible in 19 of 53 fetuses (36%, or 53% of those in whom tracking was attempted). Peak systolic global longitudinal left ventricular (RV) and right ventricular (LV) strain were similar (LV = -13.9 ± 5.7%, RV = -14.4 ± 5.5%, p = 0.7). RV strain was higher in first trimester fetuses compared with second trimester normals (p = 0.003). Intraobserver and interobserver agreement were moderate to strong for peak global LV and RV strain but poor for regional basal and mid-septal segments.

CONCLUSIONS

Strain measurements were feasible in one-third of retrospectively assessed early fetal echocardiograms. Global longitudinal strain may be higher in earlier than mid-gestation fetuses. © 2016 John Wiley & Sons, Ltd.

Evaluation of a Second-Generation Microtransesophageal Echocardiography Transducer and Software

Background:

Transesophageal echocardiographic imaging of small infants has been limited because of equipment size. A newer miniaturized transducer has allowed for the imaging of even the smallest patients but has been limited by intermittent poor image quality because of hardware durability. A second generation of the transducer was developed to address this problem. The aim of this study was to evaluate the performance and durability of the second-generation transducer over multiple uses and to compare the image quality from the modified transducer and new software preset to the original transducer.

Methods:

Patients undergoing transesophageal echocardiography (TEE) based on clinical indications with the original or second-generation transducers were included in the study. All studies were reviewed for image quality and unacceptable image degradation, which was defined as imaging quality inadequate for clinical use. Study review was performed by two echocardiographers.

Results:

Using the original transducer, 37 studies were performed with a mean patient weight of 3.46 ± 0.89 kg (range 2.1-5.7). Using the second-generation transducer, 65 studies were performed with a mean patient weight of 4.87 ± 2.05 kg (range 2.2-13.8). Image quality was clinically inadequate in 8 of the 35 studies with the original transducer and in zero with the second generation ( P < .0001).

Conclusions:

The second-generation transducer allows for effective use of TEE even in the smallest infants and avoids the mechanical failures associated with the first-generation release.

Observational trial of antibiotic-coated central venous catheters in critically ill pediatric patients

BACKGROUND

Catheter-associated bloodstream infections (CABSI) are among the most common and serious adverse events experienced by critically ill children. Randomized trials have demonstrated that the use of central venous catheters (CVC) coated with antiseptic solutions reduces rates of CABSI in adult patients; however, their efficacy in children has not been evaluated.

OBJECTIVE

To compare the incidence of CABSI, rate of complications, and microbiology of infection in critically ill children treated with antibiotic-coated or noncoated CVC (NC-CVC).

METHODS

A prospective observational trial was conducted in the pediatric intensive care unit (PICU) during a 13-month period. A minocycline-rifampin-coated CVC (MR-CVC) or NC-CVC was placed by PICU physicians who nonpreferentially selected CVC type.

RESULTS

We studied the outcomes associated with the first CVC placed in 225 patients, including 69 MR-CVC and 156 NC-CVC. Patients who received MR-CVC, as compared with NC-CVC, were similar in gender, age, and severity of illness at time of PICU admission. The incidence density of CABSI did not vary by catheter type [MR-CVC: 7.53 per 1000 catheter-days (95% confidence interval 2.05-19.17); NC-CVC: 8.64 CABSI per 1000 catheter-days (95% confidence interval 3.74-16.96)]. However, the median time to infection in children with MR-CVC was 3-fold longer than in children with NC-CVC [18 versus 5 days (P = 0.053)]. No difference was seen in the incidence of complications, including thrombosis and catheter site reaction, between MR- and NC-CVC. No significant difference was observed in the types of organisms recovered from patients with MR- and NC-CVC.

CONCLUSIONS

The use of MR-CVC significantly delayed the onset of CABSI in PICU patients. Larger, randomized trials are needed to better define potential differences in the incidence of CABSI, rate of complications, and microbiology of infection among pediatric patients treated with antiseptic-coated CVC and NC-CVC.

Change in infection control practices and awareness of hospital medical staff in the aftermath of SARS

Severe Acute Respiratory Syndrome (SARS) epidemic illustrated the crucial role of infection surveillance and control measures in the combat of any highly transmissible disease. We conducted an interview survey of 121 medical staff 145 doctors, 46 staff nurses and 30 medical assistants) in a state hospital in Malaysia three months after the end of SARS epidemic (from October to December 2003). Staff was grouped according to those directly involved in the care of suspected SARS patients [S+ group n=41] and those who were not [S- group; n=80]. On hand washing following sneezing, coughing and touching patients, the proportions of medical staff that reported an increase after the SARS crisis were 22.3%, 16.5% and 45.5% respectively. On wearing masks, gloves, and aprons when meeting potentially infectious patients, the proportions that reported an increase were 39.7%, 47.1% and 32.2% respectively. Significantly more staff in S+ than S- group reported these increases. Sixty percent of staff was aware of changes in hospital infection control policies after SARS; 93.4% was aware of notifying procedures, and 81.8% was aware of whom to notify in the hospital. Regarding infection isolation ward, Infectious Control Nurse and Infection Control Committee Chairman in the hospital, the proportions of staff that could correctly name them were 39.7%, 38.3% and 15.7% respectively. Significantly more in S+ than S- group could do so. However, more than half the staff claimed ignorance on the knowledge of infection isolation ward (56.2%), Infection Control Nurse (57.9%) and Chairman (65.3%). Our findings demonstrated that SARS crisis had some positive impact on the infection control practices and awareness of medical staff especially on those with direct SARS involvement. Implications for future control of infectious diseases are obvious.