Cardiac Cardiac Computed Tomography Research Articles

Automatic 3D left atrial strain extraction framework on cardiac computed tomography

Background and objectiveStrain analysis provides insights into myocardial function and cardiac condition evaluation. However, the anatomical characteristics of left atrium (LA) inherently limit LA strain analysis when using echocardiography. Cardiac computed tomography (CT) with its superior spatial resolution, has become critical for in-depth evaluation of LA function. Recent studies have explored the feasibility of CT-derived strain; however, they relied on manually selected regions of interest (ROIs) and mainly focused on left ventricle (LV). This study aimed to propose a first-of-its-kind fully automatic deep learning (DL)-based framework for three-dimensional (3D) LA strain extraction on cardiac CT. MethodsA total of 111 patients undergoing ECG-gated contrast-enhanced CT for evaluating subclinical atrial fibrillation (AF) were enrolled in this study. We developed a 3D strain extraction framework on cardiac CT images, containing a 2.5D GN-U-Net network for LA segmentation, axis-oriented 3D view extraction, and LA strain measure. The segmentation accuracy was evaluated using Dice similarity coefficient (DSC). The model-extracted LA volumes and emptying fraction (EF) were compared with ground-truth measurements using intraclass correlation coefficient (ICC), correlation coefficient (r), and Bland-Altman plot (B-A). The automatically extracted LA strains were evaluated against the LA strains measured from 2D echocardiograms. We utilized this framework to gauge the effect of AF burden on LA strain, employing the atrial high rate episode (AHRE) burden as the measurement parameter. ResultsThe GN-U-Net LA segmentation network achieved a DSC score of 0.9603 on the test set. The framework-extracted LA estimates demonstrated excellent ICCs of 0.949 (95 % CI: 0.93–0.97) for minimal LA volume, 0.904 (95 % CI: 0.86–0.93) for maximal LA volume, and 0.902 (95 % CI: 0.86–0.93) for EF, compared with expert measurements. The framework-extracted LA strains demonstrated moderate agreement with the LA strains based on 2D echocardiography (ICCs >0.703). Patients with AHRE > 6 min had significantly lower global strain and LAEF, as extracted by the framework than those with AHRE ≤ 6 min. ConclusionThe promising results highlighted the feasibility and clinical usefulness of automatically extracting 3D LA strain from CT images using a DL-based framework. This tool could provide a 3D-based alternative to echocardiography for assessing LA function.

Diagnostic performance of unenhanced electrocardiogram-gated cardiac CT for detecting myocardial edema.

To assess the diagnostic performance of unenhanced electrocardiogram (ECG)-gated cardiac computed tomography (CT) for detecting myocardial edema, using MRI T2 mapping as the reference standard. This retrospective study protocol was approved by our institutional review board, which waived the requirement for written informed consent. Between December 2017 to February 2019, consecutive patients who had undergone T2 mapping for myocardial tissue characterization were identified. We excluded patients who did not undergo unenhanced ECG-gated cardiac CT within 3 months from MRI T2 mapping or who had poor CT image quality. All patients underwent unenhanced ECG-gated cardiac CT with an axial scan using a third-generation, 320 × 0.5 mm detector-row CT unit. Two radiologists together drew regions of interest (ROIs) in the interventricular septum on the unenhanced ECG-gated cardiac CT images. Using T2 mapping as the reference standard, the diagnostic performance of unenhanced cardiac CT for detecting myocardial edema was evaluated by using the area under the receiver operating characteristic curve with sensitivity and specificity. Youden index was used to find an optimal sensitivity-specificity cutoff point. A cardiovascular radiologist independently performed the measurements, and interobserver reliability was assessed using intraclass correlation coefficients for CT value measurements. A P value of <.05 was considered statistically significant. We included 257 patients who had undergone MRI T2 mapping. Of the 257 patients, 35 patients underwent unenhanced ECG-gated cardiac CT. One patient was excluded from the study because of poor CT image quality. Finally, 34 patients (23 men; age 64.7 ± 14.6 years) comprised our study group. Using T2 mapping, we identified myocardial edema in 19 patients. Mean CT and T2 values for 34 patients were 46.3 ± 2.7 Hounsfield unit and 49.0 ± 4.9 ms, respectively. Mean CT values moderately correlated with mean T2 values (Rho = -0.41; P < .05). Mean CT values provided a sensitivity of 63.2% and a specificity of 93.3% for detecting myocardial edema, with a cutoff value of ≤45.0 Hounsfield unit (area under the receiver operating characteristic curve = 0.77; P < .01). Inter-observer reproducibility in measuring mean CT values was excellent (intraclass correlation coefficient = 0.93; [95% confidence interval: 0.86, 0.96]). Myocardial edema could be detected by CT value of myocardium in unenhanced ECG-gated cardiac CT.

Long-Term Clinical Implications of High-Risk Cardiac Computed Tomography Findings in Patients With Acute Ischemic Stroke.

Cardiac computed tomography (CT) acquired during the initial acute stroke imaging protocol (acute cardiac CT) is increasingly used to screen for cardioembolism, but information on the long-term clinical implications of its findings is lacking. We performed a prospective, single-center cohort study in which consecutive patients with ischemic stroke underwent ECG-gated acute cardiac CT and were followed up for 2 years. The primary outcome was functional outcome assessed using the modified Rankin Scale. Secondary outcomes were death and occurrence of major adverse cardiovascular events (composite of recurrent ischemic stroke, myocardial infarction, and cardiovascular death). We compared patients with and without a high-risk structural source of embolism on acute cardiac CT. Of 452 included patients, 55 (12.2%) had a high-risk source of embolism, predominantly cardiac thrombi (38 patients) and signs of endocarditis (8 patients). Follow-up at 2 years was complete for 430 (95.1%) patients. Patients with a high-risk source of embolism had a worse functional outcome (median modified Rankin Scale, 6 [IQR, 2-6] versus 2 [IQR, 1-5]; adjusted common odds ratio, 2.92 [95% CI, 1.62-5.25]), increased mortality rate (52.7% versus 23.7%; adjusted hazard ratio [HR], 3.28 [95% CI, 1.94-5.52]), and major adverse cardiovascular events (38.9% versus 17.5%; adjusted HR, 3.20 [95% CI, 1.80-5.69]). A high-risk source of embolism was not associated with recurrent ischemic stroke (11.1% versus 9.6%; adjusted HR, 1.30 [95% CI, 0.49-3.44]). Structural high-risk sources of embolism on acute cardiac CT in patients with ischemic stroke were associated with poor long-term functional outcome and occurrence of major adverse cardiovascular events but not with recurrent stroke.

Hybrid U-Net and Swin-transformer network for limited-angle cardiac computed tomography

Objective. Cardiac computed tomography (CT) is widely used for diagnosis of cardiovascular disease, the leading cause of morbidity and mortality in the world. Diagnostic performance depends strongly on the temporal resolution of the CT images. To image the beating heart, one can reduce the scanning time by acquiring limited-angle projections. However, this leads to increased image noise and limited-angle-related artifacts. The goal of this paper is to reconstruct high quality cardiac CT images from limited-angle projections. Approach. The ability to reconstruct high quality images from limited-angle projections is highly desirable and remains a major challenge. With the development of deep learning networks, such as U-Net and transformer networks, progresses have been reached on image reconstruction and processing. Here we propose a hybrid model based on the U-Net and Swin-transformer (U-Swin) networks. The U-Net has the potential to restore structural information due to missing projection data and related artifacts, then the Swin-transformer can gather a detailed global feature distribution. Main results. Using synthetic XCAT and clinical cardiac COCA datasets, we demonstrate that our proposed method outperforms the state-of-the-art deep learning-based methods. Significance. It has a great potential to freeze the beating heart with a higher temporal resolution.

Epicardial adipose tissue volume assessed by cardiac CT as a predictor of atrial fibrillation recurrence following catheter ablation

IntroductionIn patients with atrial fibrillation (AF), up to one third have recurrence after a first catheter ablation (CA). Epicardial adipose tissue (EAT) has been considered to be closely related to AF, with a potential role in its recurrence. We aimed to evaluate the association between the volume of EAT measured by cardiac computed tomography (CT) and AF recurrence after CA. MethodsConsecutive AF patients underwent a standardized cardiac CT protocol for quantification of EAT, thoracic adipose volume (TAV) and left atrium (LA) volume before CA. An appropriate cut-off of EAT was determined and risk recurrence was estimated. Results305 patients (63.6 % male, mean age 57.5 years, 28.2 % persistent AF) were followed for 24 months; 23 % had AF recurrence at 2-year mark, which was associated with higher EAT (p = 0.037) and LAV (p < 0.001). Persistent AF was associated with higher EAT volumes (p = 0.010), TAV (p = 0.003) and LA volumes (p < 0.001). EAT was predictive of AF recurrence (p = 0.044). After determining a cut-off of 92 cm3, survival analysis revealed that EAT volumes > 92 cm3 showed higher recurrence rates at earlier time points after the index ablation procedure (p = 0.006), with a HR of 1.95 (p = 0.008) of AF recurrence at 2-year. After multivariate adjustment, EAT > 92 cm3 remained predictive of AF recurrence (p = 0.028). ConclusionThe volume of EAT measured by cardiac CT can predict recurrence of AF after ablation, with a volume above 92 cm3 yielding almost twice the risk of arrhythmia recurrence in the first two years following CA. Higher EAT and TAV are also associated with persistent AF.

Choosing the Adaptive Cardiac Phase for Assessing Cardiac Dimensions Using Cardiac Computed Tomography for Heart Disease.

This study aimed to provide characteristics of normal heart and choose the correct cardiac cycle to measure maximum cardiac parameters for cardiovascular disease. The parameters of left atrium (LA), LV, right atrium (RA), and right ventricle (RV), as well as the wall thickness of LV, were measured in different cardiac phases using cardiac computed tomography (CT). Then, their differences in different phases and the correlation between these parameters and traditional risk factors were analyzed. In addition, receiver operator characteristic curve (ROC) analyses was performed to estimate LA enlargement. The dimensions of LA and RA as well as the wall thickness of LV reached the maximum at the phase of 35% - 45%, while the dimensions of LV and RV reached the maximum at 95% - 5%. However, the changes of LA-B (antero-posterior diameter), LV-D1 (basal dimension), RA-B (minor dimension), and RV-D2 (mid cavity dimension) were relatively more stable than other diameters during the cardiac cycle. The maximum LA-B diameter, LV-D1 diameter, RA-B diameter, and RV-D2 diameter as well as the maximum interventricular septum thickness were acquired. Heart rate (HR) and smoking were potential indicators of LV-D2 (mid cavity dimension), while HR and LV myocardial mass were potential indicators of LV-D3 (apical-basal dimension). In phase 45%, the cut-off value of LA-B was 37.12 mm, with high sensitivity for predicting LA enlargement. Choosing the adaptive cardiac phase for evaluating cardiac chamber dimensions and wall thickness obtained by cardiac CT could provide a more accurate clinical measurement of the heart.</P>.

Changes in pulmonary vein size and narrowing depend on the cardiac cycle before and after pulmonary vein isolation.

Accurate measurement of the pulmonary vein dimension (PVD) is important for determining stenosis and efficacy following pulmonary vein isolation (PVI). Little is known about the quantitative evaluation of the impact of the cardiac cycle on pulmonary vein (PV) morphology before and after PVI. This study aims to investigate variations in the ostial size of the PV during the cardiac cycle before and after PVI and the effect of the cardiac cycle on PV stenosis and reduction rate using cardiac computed tomography (CT). Sixty-eight patients with atrial fibrillation who underwent cardiac CT before and after PVI at our institution between 23 January 2021 and 5 February 2022 were retrospectively analyzed. The maximum and minimum PVD were measured at each segment before and after the PV. Each PV was evaluated according to the PVD reduction rate (ΔPVD), calculated as follows: (1 - post-PVD/pre-PVD) × 100 (%). The average dimension of all PVs at the end-diastolic frame was significantly reduced compared to that at the end-systolic frame before PVI. The average dimensions of the right superior and right inferior PV at the end-diastolic frame were significantly reduced compared with those at the end-systolic frame following PVI. The average reduction rate of dimension-classified stenosis of PVs, except for the left inferior PV at the end-diastolic frame, was significantly reduced compared with that at the end-systolic frame. The cardiac cycle affects PVD assessment, including PV stenosis, after PVI. PVD measurement is recommended to be unified to the end-systolic frame of the cardiac cycle to avoid underestimating PV stenosis before and after PVI, ensuring appropriate management and follow-up.

Abstract P431: Heparin-Warfarin Administered for Pulmonary Vein Thrombi Partially Dissolves Thrombi and Ameliorates Mild to Moderate Type 2 Diabetes Mellitus

Background: Pulmonary infection generates arterial thrombi, an important component of which are neutrophil extracellular traps, to defend the host. Pulmonary vein thrombi (PVTs) are underrated compared to arterial thrombi. In 2014, we reported that at least 61% (35 of 57) of elderly patients with chest pain had PVTs, as estimated using cardiac computed tomography (CT), and in 2022, we reported that 98.6% (215 of 218) of senior patients with age-related diseases such as hypertension, dyslipidemia, and type 2 diabetes mellitus (T2DM) had PVTs, as evaluated using cardiac CT and transesophageal echocardiography. T2DM is a common disease that can cause atherosclerosis, leading to ischemic stroke and acute myocardial infarction. It is important to better understand the mechanisms of T2DM and how to treat T2DM patients. The relationships between PVTs and T2DM are still unclear. Additionally, the relationships between heparin-warfarin therapy and T2DM are unknown. Methods: We identified PVTs in 15 T2DM patients (73.5 ± 9.9 y.o., range 50 y.o. to 88 y.o.; 10 males and 5 females) using both cardiac CT and transesophageal echocardiography. Among the 15 patients, two did not take DM medications; one took one DM medication; one took two DM medications; five took three DM medications; four took 4 DM medications; one took 5 DM medications; and one was treated with insulin. Results: The PVTs were partially dissolved by standard doses of heparin and warfarin given at the same time for one month. During the treatment, blood glucose levels were examined 30 minutes before breakfast, lunch, dinner and sleep. Between one and two weeks, the blood glucose levels of 10 patients decreased, especially before lunch, and some patients showed symptoms of hypoglycemia; therefore, the number of administered DM medications was decreased to zero for 6 patients and to one for 4 patients. After one month, the patients’ HbA1c levels had decreased slightly. We treated 10 patients with warfarin for the next several months, none of whom needed to resume DM medications, although their blood glucose tended to increase slightly. Three patients with comparatively severe T2DM showed no change in blood glucose following therapy. Conclusions: Heparin-warfarin therapy partially dissolved PVTs and decreased DM medications in patients with mild to moderate T2DM.

CAR and CSTR Cardiac Computed Tomography (CT) Practice Guidelines: Part 1 Coronary CT Angiography (CCTA).

Imaging the heart is one of the most technically challenging applications of Computed Tomography (CT) due to the presence of cardiac motion limiting optimal visualization of small structures such as the coronary arteries. Electrocardiographic gating during CT data acquisition facilitates motion free imaging of the coronary arteries. Since publishing the first version of the Canadian Association of Radiologists (CAR) cardiac CT guidelines, many technological advances in CT hardware and software have emerged necessitating an update. The goal of these cardiac CT practice guidelines is to present an overview of the current evidence supporting the use of cardiac CT in various clinical scenarios and to outline standards of practice for patient safety and quality of care when establishing a cardiac CT program in Canada.

CAR and CSTR Cardiac Computed Tomography (CT) Practice Guidelines: Part 2-Non-Coronary Imaging.

The cardiac computed tomography (CT) practice guidelines provide an updated review of the technological improvements since the publication of the first Canadian Association of Radiologists (CAR) cardiac CT practice guidelines in 2009. An overview of the current evidence supporting the use of cardiac CT in the most common clinical scenarios, standards of practice to optimize patient preparation and safety as well as image quality are described. Coronary CT angiography (CCTA) is the focus of Part I. In Part II, an overview of cardiac CT for non-coronary indications that include valvular and pericardial imaging, tumour and mass evaluation, pulmonary vein imaging, and imaging of congenital heart disease for diagnosis and treatment monitoring are discussed. The guidelines are intended to be relevant for community hospitals and large academic centres with established cardiac CT imaging programs.

Automatic thoracic aorta calcium quantification using deep learning in non-contrast ECG-gated CT images

Thoracic aorta calcium (TAC) can be assessed from cardiac computed tomography (CT) studies to improve cardiovascular risk prediction. The aim of this study was to develop a fully automatic system to detect TAC and to evaluate its performance for classifying the patients into four TAC risk categories. The method started by segmenting the thoracic aorta, combining three UNets trained with axial, sagittal and coronal CT images. Afterwards, the surrounding lesion candidates were classified using three combined convolutional neural networks (CNNs) trained with orthogonal patches. Image datasets included 1190 non-enhanced ECG-gated cardiac CT studies from a cohort of cardiovascular patients (age 57 ± 9 years, 80% men, 65% TAC > 0). In the test set (N = 119), the combination of UNets was able to successfully segment the thoracic aorta with a mean volume difference of 0.3 ± 11.7 ml (<6%) and a median Dice coefficient of 0.947. The combined CNNs accurately classified the lesion candidates and 87% of the patients (N = 104) were accurately placed in their corresponding risk categories (Kappa = 0.826, ICC = 0.9915). TAC measurement can be estimated automatically from cardiac CT images using UNets to isolate the thoracic aorta and CNNs to classify calcified lesions.

Long-term outcomes of extracardiac Gore-Tex conduits in Fontan patients

BackgroundExtracardiac conduit Fontan procedure (ECFP) employing a Gore-Tex conduit has been widely used for patients with single ventricle physiology; however, the long-term status of the conduit is unknown. We investigated the changes in a Gore-Tex conduit after ECFP and the factors associated with its narrowing. MethodsWe conducted a retrospective analysis of 86 patients who underwent ECFP between January 1995 and December 2008 and had cardiac computed tomography (CT) during the follow-up period. ResultsThe median patient age at ECFP was 2.8 years (range 1.6–9.7), and a cardiac CT was obtained at 13.1 ± 3.4 years later. The minimum conduit area decreased by approximately two-thirds of the original due to calcification, pseudointimal hyperplasia, thrombus, and luminal irregularity. The normalized minimum conduit area was influenced by the time interval from ECFP and normalized original conduit area at ECFP. An oversized conduit was associated with a narrowing of both its sides and a high frequency of pseudointimal hyperplasia or mural thrombus. The ratio of minimum conduit-to-inferior vena cava areas was lower in patients with chronic liver disease than in those with a normal liver. The maximum percent stenosis of the conduit correlated with oxygen pulse and heart rate during peak exercise. ConclusionsUsing a larger conduit at ECFP resulted in a larger minimum conduit area at follow-up. However, oversizing requires careful monitoring for stenosis near anastomotic sites and the occurrence of pseudointimal hyperplasia or thrombus.

Potential of Transthoracic Echocardiography and Cardiac CT in Pulmonary Arteries Assessment in Children With Pulmonary Atresia With Ventricular Septal Defect

Objective: To assess and compare the potential of transthoracic echocardiography (TTE) and cardiac computed tomography (CT) in determining severity of pulmonary artery hypoplasia in children with pulmonary atresia with ventricular septal defect (PA-VSD) during preoperative planning.Materials and methods: The study included 38 children (mean age, 1.5 years; 97% of the patients younger than 1 year) with a clinical diagnosis of PA-VSD. All the patients underwent TTE; 36 of them underwent cardiac CT, while 33 children had direct angiocardiography. During all diagnostic methods we performed morphometry of the pulmonary trunk (if any) and proximal and distal parts of right and left pulmonary arteries, calculated z score for every vessel, Nakata index, and McGoon ratio. All the results were compared with fiof direct angiography and/or intraoperative data. The interval between TTE, cardiac CT, and angiocardiography or open surgery was less than 10 days. The criterion for hypoplasia of the pulmonary artery and its branches was z score deviation less than (−2) from reference values. Nakata index less than 200 mm2/m2 and McGoon ratio less than 1.0 were considered contraindications for radical correction.Results: We found no statistically significant difference (P &gt; .05) when comparing the potential of TTE and cardiac CT with direct angiography/intraoperative data in terms of morphometry of the proximal parts of the right and left pulmonary arteries and calculating z scores. All the methods demonstrated high diagnostic efficacy. We found statistically significant differences when comparing the potential of TTE and cardiac CT in pulmonary trunk angiometry: the results of pulmonary trunk measurement using TTE were statistically significantly different from the findings of cardiac CT and angiography/intraoperative data with significant underestimation of vessel diameters (P &lt; .05). The results of measurements of the distal parts of the pulmonary artery using TTE were statistically significantly different from those of cardiac CT and direct angiography/intraoperative data with significant underestimation of vessel diameters (P &lt; .05). There were no statistically significant differences between CT and direct angiography/intraoperative data in assessing the diameters of the distal branches of the pulmonary artery. When assessing McGoon ratio and Nakata index using TTE, we found statistically significant differences (underestimation of values) in comparison with direct angiography (P &lt; .05). Comparison of McGoon ratios measured by TTE and cardiac CT also demonstrated their statistically significant underestimation by TTE (P &lt; .05). The calculated McGoon ratio during cardiac CT did not differ significantly from the direct angiography findings.Conclusions: TTE cannot be considered the final method for preoperative assessment of the pulmonary artery system development in children with PA-VSD due to the limited visualization of the distal parts of the right and left pulmonary arteries and significant underestimation of the pulmonary trunk diameter and indices. Cardiac CT proved its high effectiveness in assessment of hypoplasia severity and can be an alternative to direct angiography.

Prevalence of major embolic findings and incidental findings on early cardiac CT in patients with suspected ischemic stroke

PurposeThe purpose of this study was to assess the type and prevalence of stroke and non-stroke-related findings diagnosed on early cardiac computed tomography (CT) in patients with suspected stroke. The secondary objective was to assess the clinical consequences on the management of patients with non-stroke-related conditions identified by early cardiac CT. Materials and methodsThis single-center, retrospective, observational study included 1111 consecutive patients with suspected ischemic stroke between November 2018 and March 2020 who underwent cardiac CT examination in addition to the usual brain CT protocol (i.e., non-enhanced brain CT, perfusion brain CT when needed, aortic arch and supra-aortic CT angiography, and post contrast brain CT). There were 562 women and 549 men with a median age of 74 years (range: 60–85 years). Of these, 415 (415/1111; 37.4%) patients had ischemic stroke and 692 (692/1111; 62.3%) had no stroke. Cardiac CT examinations were retrospectively reviewed for cardiac CT findings at high embolic risk and clinically significant extracardiac incidental findings. ResultsAmong 1111 included patients, 89 (89/1111; 8.0%) had a stroke-related condition identified on early cardiac CT. This was significantly more frequent in patients with ischemic stroke (66/415; 15.9%) by comparison with those without ischemic stroke (23/696; 3.3%) (P < 0.001), with 41 patients (41/415; 9.9%) diagnosed with left atrial thrombus. Cardiac CT revealed a clinically significant non-stroke-related finding in 173 patients (173/1111; 15.6%), including 17 pulmonary embolisms (1.5%), seven suspicious pulmonary lesions (0.6%), and three breast lesions suspected to be malignant (0.3%). Twenty out of 173 patients (20/173; 11.5%) with incidental findings on early cardiac CT had a change in their management. ConclusionThis study shows that adding early cardiac CT to brain CT during the acute phase of an ischemic stroke leads to a higher rate of etiological diagnoses and highlights the major interest of looking at the bigger picture.

A large type I right pulmonary artery to left atrium fistula: underwent successful percutaneous device closure with duct occluder—a rare case report

BackgroundPulmonary artery to left atrium fistula is an unusual structural cause of silent cyanosis. Only less than 100 cases have been reported so far. A high index of clinical suspicion and proper evaluation with bubble contrast echocardiography and cardiac computed tomography (CT) will help to detect this treatable anomaly. The advent of safer percutaneous closure methods has replaced the need for more invasive surgical closure.Case presentationWe report an adolescent boy, who presented with long-standing cyanosis and progressive dyspnea with normal clinical cardiovascular examination. On evaluation, echocardiography and bubble contrast study revealed a large right pulmonary artery (RPA) to left atrium (LA) fistula. Cardiac CT confirmed the same with normal pulmonary venous drainage s/o a large 20 mm Type I RPA LA Fistula. He underwent successful percutaneous closure of the fistula tract with a 22 × 24 mm Cera™ duct occluder via transseptal approach uneventfully.ConclusionOur case enlightens the methodological approach to diagnosing this rare anomaly as well as the feasibility of percutaneous intervention in such cases as it is one of the largest fistula tracts closed percutaneously to date.

Cardiac Computed Tomography Angiography in Infants and Young Children Without Sedation.

Cardiac computed tomography (CT) imaging plays a pivotal role in the diagnosis and management of infants and young children with congenital heart disease (CHD). While the benefits of CT imaging are well-established, the challenge lies in adapting these procedures to the unique requirements of infants and young children. Traditionally, sedation has been a common practice to ensure cooperation and motion control during imaging. However, using sedation introduces its challenges including potential risks, limitations, and cost implications. In this study, authors explore the feasibility, safety, and diagnostic accuracy of unsedated cardiac CT examinations in infants and young children. This study proves cardiac CT can be performed in India without sedation using simple restraining techniques. This approach aligns with the cultural and familial dynamics prevalent in the country and holds the potential to address economic and infrastructure challenges.

Airway Tree Caliber and Susceptibility to Pollution-associated Emphysema: MESA Air and Lung Studies.

Airway tree morphology varies in the general population and may modify the distribution and uptake of inhaled pollutants. We hypothesized that smaller airway caliber would be associated with emphysema progression and would increase susceptibility to air pollutant-associated emphysema progression. The Multi-Ethnic Study of Atherosclerosis (MESA) is a general population cohort of adults 45-84 years old from six U.S. communities. Airway tree caliber was quantified as the mean of airway lumen diameters measured from baseline cardiac computed tomography (CT) (2000-02). Percent emphysema, defined as percentage of lung pixels below -950 Hounsfield units, was assessed up to 5 times per participant via cardiac CT scan (2000-07) and equivalent regions on lung CT scan (2010-18). Long-term outdoor air pollutant concentrations (PM2.5, NOx, O3) were estimated at residential address with validated spatio-temporal models. Linear mixed models estimated the association between airway tree caliber and emphysema progression; modification of pollutant-associated emphysema progression was assessed using multiplicative interaction terms. Among 6,793 participants (mean±SD age: 62±10 years), baseline airway tree caliber was 3.95±1.1 mm and median (interquartile range) of percent emphysema was 2.88 (1.21-5.68). In adjusted analyses, 10-year emphysema progression rate was 0.75 percentage points (95%CI 0.54-0.96%) higher in the smallest compared to largest airway tree caliber quartile. Airway tree caliber also modified air pollutant-associated emphysema progression. Smaller airway tree caliber was associated with accelerated emphysema progression and modified air pollutant-associated emphysema progression. A better understanding of mechanisms of airway-alveolar homeostasis and air pollutant deposition are needed.

Accuracy of Transthoracic Echocardiography in Detecting Persistent Left Superior Vena Cava against the Cardiac Computed Tomography Scan

Abstract Introduction: Detection of the persistent left superior vena cava (LSVC) is essential to diagnosing pediatric congenital heart diseases (CHDs). Transthoracic echocardiography is the most commonly used diagnostic tool for CHDs. This study compares transthoracic echocardiography and cardiac computed tomography (CT) to detect LSVC. Methods: Retrospective review of 49 pediatrics patients with CHDs who underwent echocardiography and cardiac CT. Results: Forty-nine pediatric patients with CHDs who underwent CT scans were included. In acyanotic CHD patients, CT identified four with bilateral superior vena cava (SVC), while echocardiography picked up three and missed one. In the remaining 16 patients with acyanotic CHDs, CT found single right-sided SVC; however, two of these were misidentified as having bilateral SVC during echocardiography. In the cyanotic CHD group, four patients had bilateral SVC. All four were picked up by echocardiography as well. However, echocardiography diagnosed one additional patient as having bilateral SVC, while the patient actually had a single SVC on CT scan. Conclusion: Transthoracic echocardiography can reasonably detect persistent LSVC in pediatric CHD patients.

Cardiac Computed Tomography Assessment of the Variation of Papillary Muscle Morphology before Mitral Valve Surgery

Background. The morphology of the papillary muscles of the left ventricle is highly variable. Few studies have investigated papillary muscle morphology using imaging. Objective. This study aimed to assess papillary muscle morphology with primary mitral regurgitation (MR) using cardiac computed tomography (CT). Methods. We examined 116 patients who underwent robotic mitral valve repair for primary MR using preoperative cardiac CT. Papillary muscle morphology was assessed using CT images and compared with operative findings. Results. CT images of papillary muscles were consistent with the operative findings during robotic mitral valve repair in all cases. Both the anterolateral papillary muscle (APM) and posteromedial papillary muscle (PPM) groups were identified in all cases, and the middle papillary muscle (MPM) group was identified in 24.1% of cases. The PPM group had a higher proportion of complex morphologies with more heads and bases than the APM group (head: p&lt;0.001 and base: p&lt;0.001). The PPM group had smaller papillary muscle sizes than the APM group. The MPM group in most patients had one base and one head (78.6%). Papillary muscle sizes were significantly smaller in the order of the APM, PPM, and MPM groups (p&lt;0.001). Conclusions. Cardiac CT allowed clear visualization and accurate assessment of papillary muscle morphology in the left ventricle. It may be useful to obtain the papillary muscle variations preoperatively using CT imaging in procedures involving the papillary muscles such as mitral valve repair.

Membranous Septum Length Predicts New Conduction Abnormalities in Surgical Aortic Valve Replacement: A Novel Predictor for Permanent Pacemaker Implantation After Surgical Aortic Valve Replacement

IntroductionThe membranous septum (MS) length measured by cardiac computed tomography (CT) is useful for the prediction of permanent pacemaker implantation (PPMI) and new left bundle branch block (LBBB) after transcatheter aortic valve replacement. However, its predictive value for patients undergoing surgical aortic valve replacement (SAVR) is unknown. MethodsA total of 2531 consecutive patients were registered in the institutional Society of Thoracic Surgeons database between July 2017 and June 2020. Patients who underwent non-SAVR procedures, had prior pacemaker/implantable cardioverter defibrillator, prior SAVR, no preprocedural CT assessment, or suboptimal CT imaging were excluded. ResultsA total of 126 SAVR with preprocedural CT assessment were analyzed. Bicuspid aortic valve morphology was confirmed on CT in 59.5% of patients. There were three new PPMIs and five new LBBBs observed after SAVR at the time of discharge. In-hospital mortality was 0.8%. Low left ventricular (LV) ejection fraction (<50%), LV mass index >120 g/m2, large right coronary artery height, and MS length <1.5 mm predicted new PPMI/LBBB. Multivariate analysis showed LV mass index >120 g/m2 (odds ratio: 9.165; 95% confidence interval: 1.644-51.080; P = 0.011) and MS length <1.5 mm (odds ratio: 14.449; 95% confidence interval: 1.632-127.954; P = 0.016) were independent predictors for new PPMI/LBBB. ConclusionsShort MS length on preoperative cardiac CT is a powerful and novel predictor for the risk of new PPMI/LBBB after SAVR. Special care should be taken in patients with short MS length to avoid suture-mediated trauma.