This study aims to evaluate the feasibility of turbulent kinetic energy (TKE) assessments using compressed sensing (CS)-accelerated three-dimensional time-resolved phase-contrast magnetic resonance imaging (4D flow MRI) in patients with aortic stenosis (AS). Conventional and CS 4D flow MRI (R = 2 with GRAPPA and R = 7.7 with CS, respectively) were sequentially acquired for voxel-wise comparison in healthy participants and patients. Total TKE was measured in both the ascending aorta (AAo) and the whole aortic region. The difference between GRAPPA and CS was expressed as the ratio of (CS 4D flow - Conventional 4D flow) to (Conventional 4D flow). A two-tailed paired t-test was used to assess statistical significance. In healthy participants, the maximum total TKE (TKEmax) measured by CS 4D flow MRI was substantially higher than that obtained with conventional 4D flow MRI, showing a 95.4% increase in the AAo region (0.74 ± 0.43 mJ by GRAPPA vs. 1.17 ± 0.72 mJ by CS; P = 0.053) and a 207.7% increase in the whole aortic region (1.13 ± 0.73 mJ by GRAPPA vs. 2.13 ± 0.95 mJ by CS; P = 0.006). In patients with AS, CS 4D flow MRI showed good agreement with conventional imaging, with only a 5.0% difference in TKEmax at the AAo (14.0 ± 4.6 mJ by GRAPPA vs. 14.8 ± 5.5 mJ by CS; P = 0.129) and a 7.4% difference in the whole region (16.3 ± 5.5 mJ by GRAPPA vs. 17.6 ± 6.5 mJ by CS; P = 0.050). CS 4D flow MRI demonstrated agreement, showing insignificant differences in total TKE measurements specifically within the AAo for AS patients. In healthy participants, CS-based TKE assessment showed larger relative differences compared with conventional 4D flow MRI, likely reflecting a low-TKE effect.

PURPOSE:Identifying factors associated with left ventricular (LV) remodeling is important for risk stratification of patients with moderate aortic stenosis (AS). The aim of this preliminary study was to explore aortic hemodynamics in these patients and assess their relationships with LV remodeling using four-dimensional (4D) flow magnetic resonance imaging (MRI). METHOD:Data from 17 patients with moderate AS involving the tricuspid aortic valves and normal LV ejection fraction (EF > 55%) were analyzed. All patients underwent 4D flow MRI of the ascending aorta and cardiac magnetic resonance (CMR) on the same day within 1 month of being diagnosed with moderate AS by transthoracic Doppler echocardiography. 4D flow MRI aortic parameters, including turbulent kinetic energy (TKE), both total and peak; peak wall shear stress (WSS); and the vortex and helix flow severity, were assessed. CMR measures comprised LV structure and function, late gadolinium enhancement (LGE), myocardial native T1 mapping, and extracellular volume fraction. RESULTS:The minimum and maximum values of total TKE, peak TKE, and peak WSS were 39.4/160.3 mJ, 876.6/2059.6 J/m3, and 2.0/4.9 Pa, respectively. More than 50% of the patients had vortex and helix flow of Grade 2. Peak TKE significantly correlated with LV end-diastolic volume index (r = 0.675, p = 0.003), LV end-systolic volume index (r = 0.666, p = 0.003), and LV mass index (r = 0.653, p = 0.004). LGE was not observed, and peak TKE also showed an inverse correlation with native T1 value (r = -0.571, p = 0.017). CONCLUSIONS:Among patients with moderate AS, 4D flow MRI revealed heterogeneous aortic hemodynamic profiles and peak TKE was a significant hemodynamic parameter related to early LV remodeling. However, these findings need to be confirmed in further studies with larger sample sizes and a long-term serial follow-up data.

The Asian Society of Cardiovascular Imaging-Practical Tutorial (ASCI-PT) is an instructional initiative of the ASCI School designed to enhance educational standards. In 2021, the ASCI-PT was convened with the goal of formulating a consensus statement on the assessment of coronary stenosis and coronary plaque using coronary CT angiography (CCTA). Nineteen experts from four countries conducted thorough reviews of current guidelines and deliberated on eight key issues to refine the process and improve the clarity of reporting CCTA findings. The experts engaged in both online and on-site sessions to establish a unified agreement. This document presents a summary of the ASCI-PT 2021 deliberations and offers a comprehensive consensus statement on the evaluation of coronary stenosis and coronary plaque in CCTA.

Abstract Objective We aimed to develop and validate the automatic quantification of coronavirus disease 2019 (COVID-19) pneumonia on computed tomography (CT) images. Methods This retrospective study included 176 chest CT scans of 131 COVID-19 patients from 14 Korean and Chinese institutions from January 23 to March 15, 2020. Two experienced radiologists semiautomatically drew pneumonia masks on CT images to develop the 2D U-Net for segmenting pneumonia. External validation was performed using Japanese (n = 101), Italian (n = 99), Radiopaedia (n = 9), and Chinese data sets (n = 10). The primary measures for the system's performance were correlation coefficients for extent (%) and weight (g) of pneumonia in comparison with visual CT scores or human-derived segmentation. Multivariable logistic regression analyses were performed to evaluate the association of the extent and weight with symptoms in the Japanese data set and composite outcome (respiratory failure and death) in the Spanish data set (n = 115). Results In the internal test data set, the intraclass correlation coefficients between U-Net outputs and references for the extent and weight were 0.990 and 0.993. In the Japanese data set, the Pearson correlation coefficients between U-Net outputs and visual CT scores were 0.908 and 0.899. In the other external data sets, intraclass correlation coefficients were between 0.949–0.965 (extent) and between 0.978–0.993 (weight). Extent and weight in the top quartile were independently associated with symptoms (odds ratio, 5.523 and 10.561; P = 0.041 and 0.016) and the composite outcome (odds ratio, 9.365 and 7.085; P = 0.021 and P = 0.035). Conclusions Automatically quantified CT extent and weight of COVID-19 pneumonia were well correlated with human-derived references and independently associated with symptoms and prognosis in multinational external data sets.

Objective This study aimed to evaluate the effect of implementing the consensus statement from the Asian Society of Cardiovascular Imaging-Practical Tutorial 2020 (ASCI-PT 2020) on the reliability of cardiac MR with late gadolinium enhancement (CMR-LGE) myocardial viability scoring between observers in the context of ischemic cardiomyopathy. Materials and Methods A total of 17 cardiovascular imaging experts from five different countries evaluated CMR obtained in 26 patients (male:female, 23:3; median age [interquartile range], 55.5 years [50–61.8]) with ischemic cardiomyopathy. For LGE scoring, based on the 17 segments, the extent of LGE in each segment was graded using a five-point scoring system ranging from 0 to 4 before and after exposure according to the consensus statement. All scoring was performed via web-based review. Scores for slices, vascular territories, and total scores were obtained as the sum of the relevant segmental scores. Interobserver reliability for segment scores was assessed using Fleiss’ kappa, while the intraclass correlation coefficient (ICC) was used for slice score, vascular territory score, and total score. Inter-observer agreement was assessed using the limits of agreement from the mean (LoA). Results Interobserver reliability (Fleiss’ kappa) in each segment ranged 0.242–0.662 before the consensus and increased to 0.301–0.774 after the consensus. The interobserver reliability (ICC) for each slice, each vascular territory, and total score increased after the consensus (slice, 0.728–0.805 and 0.849–0.884; vascular territory, 0.756–0.902 and 0.852–0.941; total score, 0.847 and 0.913, before and after implementing the consensus statement, respectively. Interobserver agreement in scoring also improved with the implementation of the consensus for all slices, vascular territories, and total score. The LoA for the total score narrowed from ± 10.36 points to ± 7.12 points. Conclusion The interobserver reliability and agreement for CMR-LGE scoring for ischemic cardiomyopathy improved when following guidance from the ASCI-PT 2020 consensus statement.

This document is the third part of the guidelines for the protocol, the interpretation and post-processing of cardiac magnetic resonance (CMR) studies. These consensus recommendations have been developed by the Consensus Committee of the Korean Society of Cardiovascular Imaging to standardize the requirements for image interpretation and post-processing of CMR. This third part of the recommendations describes tissue characterization modules, including perfusion, late gadolinium enhancement, and T1- and T2 mapping. Additionally, this document provides guidance for visual and quantitative assessment consisting of "What-to-See," "How-To," and common pitfalls for the analysis of each module. The Consensus Committee hopes that this document will contribute to the standardization of image interpretation and post-processing of CMR studies.

Background: We aimed to develop and distribute free artificial intelligence (AI) software for the automatic quantification of coronavirus disease 2019 (COVID-19) pneumonia on computed tomography (CT) images.Methods: We included 150 chest CT scans (17 CT scanners; five vendors) of 105 COVID-19 patients from 13 Korean and Chinese institutions. Two experienced radiologists semi-automatically drew lung opacities in every CT image, preparing 28,580 positive and negative CT slices to develop the 2D U-Net for segmenting pneumonia. The 2D U-Net was distributed as downloadable free software for local use on computers without data privacy concerns. External validation was performed using a Japanese single-institutional dataset and a public Italian dataset. Primary measures for the performance of the network were correlation coefficients for extent (%) and weight (g) of pneumonia. We surveyed user experiences.Findings: In the internal validation dataset, the intraclass correlation coefficients between the 2D U-Net and reference values for the extent and weight were 0·987 and 0·992, respectively. In the Japanese dataset, the Pearson correlation coefficients between the visual CT severity score and 2D U-Net outcomes were 0·906 and 0·916, respectively. In the Italian dataset, the intraclass correlation coefficients between the 2D U-Net and reference values for extent and weight were 0·921 and 0·970, respectively. The median satisfaction score was 9/10 and most respondents replied to use the software willingly.Interpretation: AI software for the automatic quantification of COVID-19 pneumonia on CT images was successfully developed and distributed freely worldwide. Funding Statement: There was no funding source for this study.Declaration of Interests: Sang Joon Park is the CEO of Medical IP. Gin Mo Goo has grants from Infinitt Healthcare, grants from Dongkook Lifescience, outside the submitted work. All the other authors have no potential conflicts of interest to disclose.Ethics Approval Statement: The institutional review board of the participating hospitals approved this retrospective study, and the requirement for patient consent was waived.

Objectives We aimed to develop and validate the automatic quantification of COVID-19 pneumonia on CT images. Methods This retrospective study included 176 chest CT scans of 131 COVID-19 patients from 13 Korean and Chinese institutions. Two experienced radiologists semi-automatically drew pneumonia, preparing 49,830 positive and negative CT slices to develop the 2D U-Net for segmenting pneumonia. The 2D U-Net was distributed as downloadable software. External validation for quantifications’ accuracy was performed using Japanese, Italian, Radiopaedia, Chinese datasets. Primary measures for the accuracy of the network were correlation coefficients for extent (%) and weight (g) of pneumonia. Logistic regression analyses were performed to evaluate the clinical implication of the extent and weight regarding the presence of symptoms in the Japanese dataset and the occurrence of composite outcome in the Spanish dataset. Results In the internal validation dataset, the intraclass correlation coefficients between the 2D U-Net and reference values for the extent and weight were 0.990 and 0.993, respectively. In the Japanese dataset, the Pearson correlation coefficients between the U-Net outcomes and visual CT severity scores were 0.908 and 0.899, respectively. In the other external validation datasets, the intraclass correlation coefficients between the U-Net and reference values were between 0.951-0.970 (extent) and between 0.970-0.995 (weight), respectively. In multivariate logistic regression analyses, the extent and weight of pneumonia were independently associated with symptoms (OR, 4.142 and 4.434; p=.013 and .009, respectively), and poor prognosis (OR, 7.446 and 4.677; p=.004 and .029, respectively). Conclusions CT extent and weight of COVID-19 pneumonia were automatically quantifiable and independently associated with symptoms and prognosis.

심막 질환은 응급질환인 관상동맥, 대동맥 질환과 증상이 비슷하여 빠른 감별이 중요하다. 심막은 두겹으로 된 막으로서 다양한 해부학적 변이와 질환이 있다. 크거나 비전형적인 위치를 보이는 심막의 오목(recess)은 이상 소견으로 오인될 수도 있다. 심막에는 감염이나 종양 같은 질환이 생기며 또한 주변에서 생기는 이러한 질환의 전파경로가 될 수 있다. 심막을 평가하는데 있어 심초음파가 일차적인 검사방법이나 해상도가 떨어지고 주변의 폐나 뼈에 의한 음창이 제한될 수 있으며 수술 후 평가가 힘든 경우가 많다. 이때 CT나 MR에 의한 영상평가가 유용한 경우가 많아 검사가 점점 늘어나고 있다. 심막의 형태와 질환에 대한 지식 및 영상소견에 대한 이해는 환자 치료에 중요하다.

Cardiovascular magnetic resonance imaging (CMR) is expected to be increasingly used in Korea due to technological advances and the expanded national insurance coverage of CMR assessments. For improved patient care, proper acquisition of CMR images as well as their accurate interpretation by well-trained personnel are equally important. In response to the increased demand for CMR, the Korean Society of Cardiovascular Imaging (KOSCI) has issued interpretation guidelines in conjunction with the Korean Society of Radiology. KOSCI has also created a formal Committee on CMR guidelines to create updated practices. The members of this committee review previously published interpretation guidelines and discuss the patterns of CMR use in Korea.

Cardiac magnetic resonance (CMR) imaging is widely used in many areas of cardiovascular disease assessment. This is a practical, standard CMR protocol for beginners that is designed to be easy to follow and implement. This protocol guideline is based on previously reported CMR guidelines and includes sequence terminology used by vendors, essential MR physics, imaging planes, field strength considerations, MRI-conditional devices, drugs for stress tests, various CMR modules, and disease/symptom-based protocols based on a survey of cardiologists and various appropriate-use criteria. It will be of considerable help in planning and implementing tests. In addressing CMR usage and creating this protocol guideline, we particularly tried to include useful tips to overcome various practical issues and improve CMR imaging. We hope that this document will continue to standardize and simplify a patient-based approach to clinical CMR and contribute to the promotion of public health.

Purpose We retrospectively estimated the frequency and clinical significance of pulmonary embolism (PE) that would have been missed on chest CT scans if the American College of Radiology (ACR) appropriateness criteria were applied and contrast enhanced CT scans were not performed. Materials and Methods From 2007 to 2014, a total of 696 patients with acute PE were reviewed. The ACR appropriateness criteria relevant to performing a chest CT scan were reorganized into 37 clinical topics (reasons for performing CT). Furthermore, based on the strength of recommendation for CT contrast usage, topics were divided into Group A (appropriate), Group B (not appropriate), Group C (may be appropriate), and Group D (no CT). The patients were assigned into groups and compared for the clinical characteristics and prognostic CT findings. Results Four hundred ninety-one patients were assigned into Group A (70.5%), 104 patients were assigned into Group B (14.9%), 101 patients were assigned into Group C (14.5%), and none of the patients were assigned into Group D. Patients in Group C (69.3 ± 14.6 years) were significantly older (p < 0.001) than those in the other groups. The most common reason for performing CT in Group B was screening of pulmonary metastasis (72%). Conclusion Under circumstances of many pulmonary emboli without clinical suspicion, PE could be overlooked under the application of contrast usage criteria, especially in patients in old age and with underlying malignancy. Such a recommendation can be useful to determine the usage of CT contrast in patients with a complex medical background.

OBJECTIVE. The prevalence of coronary artery fistula (CAF) based on coronary angiographic findings has been reported. However, the number of incidentally found CAFs is increasing as coronary CT angiography (CTA) has become popular. The purpose of this study was to determine the prevalence and types of CAFs detected with coronary CTA.MATERIALS AND METHODS. Between March 2009 and November 2011, 6341 patients underwent coronary CTA at one institution. The prevalence of CAF was retrospectively evaluated, and the morphologic features were analyzed, including vessel of origin, drainage site, size, and presence of an aneurysmal sac. We also analyzed cardiac and pulmonary findings.RESULTS. Among 6341 patients, 56 (0.9%) patients had CAF. The types of CAF detected, in decreasing frequency, were coronary to pulmonary artery fistula (43 cases [76.8%]), coronary to bronchial artery fistula (five cases [8.9%]), coronary artery to cardiac chamber fistula (five cases [8.9%]), combined coronary to pulmonary and coronary to bronchial artery fistula (two cases [3.6%]), and coronary artery to superior vena cava fistula (one case [1.8%]). Lung parenchymal or vascular anomaly was more frequently noted in coronary to bronchial artery fistulas, combined coronary to pulmonary and coronary to bronchial artery fistulas, and coronary artery to superior vena cava fistulas than in coronary to pulmonary artery and coronary artery to cardiac chamber fistulas.CONCLUSION. The prevalence of CAF at coronary CTA was 0.9%, which is higher than the known prevalence based on conventional angiographic findings (0.05-0.25%). Furthermore, the most common type of CAF in this study was coronary to pulmonary artery, whereas coronary artery to ventricle fistula was previously considered the most common type in studies conducted with conventional angiography. Coronary CTA is a useful, noninvasive imaging modality for the detection of CAF.

This is to report the technique of reversed iliac leg stent-graft in endovascular treatment for isolated internal iliac artery (IIA) aneurysm, which had significant size discrepancy between the common iliac artery (CIA) and external iliac artery (EIA) in 3 patients from different hospitals. Three patients were a 85- and two 82-year-old men. Treated were right IIA aneurysms, sized 6.5×6.2 cm, 5.0×4.0 cm, and 4.1 cm in longest diameter, respectively. The diameters of the right CIA and right EIA measured 21 mm/11 mm, 15 mm/11 mm, and 20 mm/10 mm, respectively. In all cases, reversed iliac leg stent-grafts were prepared on-site; unsheathed and mounted upside-down manually, and deployed in each right CIA. Post-stent-graft angiograms showed complete exclusion of the aneurysms, except for minimal type 1 endoleak in one case. This technique is a useful treatment option in patients with isolated IIA aneurysm.

Tumor seeding, along the needle tract after percutaneous needle biopsy, is a rare condition and most of the reported cases are implantation metastasis, which occurred in the chest wall or the pleura. We present a case of implantation metastasis that occurred in the pulmonary parenchyma, after a computed tomography-guided percutaneous needle biopsy (CT-PNB) of stage I lung cancer.

Coronary artery fistula (CAF) is a congenital anomaly defined as a direct precapillary connection between the coronary artery and other vascular structures. Its incidence is 0.1--0.2% in an adult population undergoing invasive angiography (1, 2). CAF usually terminates in the right ventricle, right atrium, and the pulmonary artery; CAF to the bronchial artery is very rare (3-5). The sinoatrial node (SAN) artery has various courses, and one important variant of this is the S-shaped SAN artery (6). Bronchial-to-SAN artery fistula has been mentioned in some previous reports, but a detailed description of its course on CT images has not been reported (4, 7). Herein we report a rare case of CAF to the bronchial artery from the S-shaped variant of the SAN artery, which was incidentally found on coronary angiography but its detailed course elucidated only after reviewing the coronary CT angiography (CCTA) images.

Spontaneous pneumomediastinum is an uncommon disorder, and usually affects young men and has a benign course.Common triggers are asthma, the smoking of illicit drugs, the Valsalva maneuver, and respiratory infections.Most cases are usually due to alveolar rupture into the pulmonary interstitium caused by excess pressure.The air dissects to the hilum along the peribronchovascular sheaths and spreads into the mediastinum.However, pneumomediastinum following pharyngeal perforation is very rare, and has only been reported in relation to dental procedures, head and neck surgery, or trauma.We report a case of pneumomediastinum that developed in a 43-year-old patient with pharyngeal perforation after shouting.His course was complicated by mediastinitis and parapneumonic effusions.