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To evaluate commercial deep learning-based software for fully automated coronary artery calcium (CAC) scoring on non-electrocardiogram (ECG)-gated low-dose CT (LDCT) with different slice thicknesses compared with manual ECG-gated calcium-scoring CT (CSCT).This retrospective study included 567 patients who underwent both LDCT and CSCT. All LDCT images were reconstructed with a 2.5-mm slice thickness (LDCTCSCTFully automated CAC-scoring software with both CSCT and LDCT yielded excellent reliability and agreement with CSCT• Total Agatston scores and all vessels of CSCT

To demonstrate the relationship between spectral computed tomography (CT) measured iodine concentration and strength of aortic valvular calcification (AVC) in patients with aortic valve stenosis (AVS).A retrospective study was performed on patients who underwent transcatheter aortic valve replacement (TAVR) for symptomatic AVS and underwent both pre and postprocedural electrocardiogram gated CT scans using a spectral CT system. Preprocedural CT was used to evaluate the volume and iodine concentration (IC) in the AVC. Postprocedural CT data were used to calculate the volume reduction percentage (VRP) of AVC. Multiple linear regression analysis was used to identify the independent variables related to the VRP in AVCs.A total of 94 AVCs were selected from 22 patients. The mean volume and IC of the AVCs before TAVR were 0.37 mL ± 0.15 mL and 7 mg/mL ± 10.5 mg/mL, respectively. After TAVR, a median VRP of all 94 AVCs was 18.5%. Multiple linear regression analysis showed that the IC was independently associated with the VRP (coefficient = 1.64, p0.001). When an optimal IC cutoff point was set at 4 mg/mL in the assessment of a fragile AVC which showed the VRP was18.5%, the sensitivity was 63%; specificity, 91%; positive predictive value, 88%; and negative predictive value, 71%.When using spectral CT to prepare the TAVR, measuring the IC of the AVC may be useful to assess the probability of AVC deformity after TAVR.• A dual-layer detector-based spectral CT enables quantifying iodine of contrast media in the aortic valve calcification (AVC) on contrast-enhanced CT images. • The AVC including iodine of contrast media on contrast-enhanced CT image may have loose compositions, associated with the deformity of AVC after TAVR. • Measuring the iodine concentration in AVC may have the potential to assess the probability of AVC deformity, which may be associated with the outcome and complications after TAVR.2.

We aimed to evaluate the performance of convolutional neural networks (CNNs) in the classification of coronavirus disease 2019 (COVID‐19) disease using normal, pneumonia, and COVID‐19 chest radiographs (CXRs). First, we collected 9194 CXRs from open datasets and 58 from the Korea University Anam Hospital (KUAH). The number of normal, pneumonia, and COVID‐19 CXRs were 4580, 3884, and 730, respectively. The CXRs obtained from the open dataset were randomly assigned to the training, tuning, and test sets in a 70:10:20 ratio. For external validation, the KUAH (20 normal, 20 pneumonia, and 18 COVID‐19) dataset, verified by radiologists using computed tomography, was used. Subsequently, transfer learning was conducted using DenseNet169, InceptionResNetV2, and Xception to identify COVID‐19 using open datasets (internal) and the KUAH dataset (external) with histogram matching. Gradient‐weighted class activation mapping was used for the visualization of abnormal patterns in CXRs. The average AUC and accuracy of the multiscale and mixed‐COVID‐19Net using three CNNs over five folds were (0.99 ± 0.01 and 92.94% ± 0.45%), (0.99 ± 0.01 and 93.12% ± 0.23%), and (0.99 ± 0.01 and 93.57% ± 0.29%), respectively, using the open datasets (internal). Furthermore, these values were (0.75 and 74.14%), (0.72 and 68.97%), and (0.77 and 68.97%), respectively, for the best model among the fivefold cross‐validation with the KUAH dataset (external) using domain adaptation. The various state‐of‐the‐art models trained on open datasets show satisfactory performance for clinical interpretation. Furthermore, the domain adaptation for external datasets was found to be important for detecting COVID‐19 as well as other diseases.

To compare the coronary vasodilation effects of spray with those induced by tablet administration in coronary CT angiography (CCTA). A total of 2024 patients who underwent CCTA were identified for this retrospective study, including 828 patients with spray (spray group) and 1169 with tablets (tablet group). Of these, 93 patients underwent CCTA at least twice using both spray and tablets. The number of measurable segments and diameters of all 18 segments was measured. The number of measurable segments was compared between groups. No statistically significant differences were evident between these two groups in terms of clinical characteristics. All coronary segments except the ramus intermedius (RI) and left posterior descending artery (L-PDA) were significantly larger in the spray group than in the tablet group (all p

To propose fully automatic segmentation of left atrium using active learning with limited dataset in late gadolinium enhancement in cardiac magnetic resonance imaging (LGE-CMRI).An active learning framework was developed to segment the left atrium in cardiac LGE-CMRI. Patients (n = 98) with atrial fibrillation from the Korea University Anam Hospital were enrolled. First, 20 cases were delineated for ground truths by two experts and used for training a draft model. Second, the 20 cases from the first step and 50 new cases, corrected in a human-in-the-loop manner after predicting using the draft model, were used to train the next model; all 98 cases (70 cases from the second step and 28 new cases) were trained. An additional 20 LGE-CMRI were evaluated in each step.The Dice coefficients for the three steps were 0.85 ± 0.06, 0.89 ± 0.02, and 0.90 ± 0.02, respectively. The biases (95% confidence interval) in the Bland-Altman plots of each step were 6.36% (-14.90-27.61), 6.21% (-9.62-22.03), and 2.68% (-8.57-13.93). Deep active learning-based annotation times were 218 ± 31 seconds, 36.70 ± 18 seconds, and 36.56 ± 15 seconds, respectively.Deep active learning reduced annotation time and enabled efficient training on limited LGE-CMRI.

Background Electrophysiology studies have demonstrated that left atrial late gadolinium enhancement (LGE) is associated with the chronicity of atrial fibrillation (AF). To date, cardiac MRI has been used to assess the extent of atrial LGE but not the distribution pattern of LGE in the left atrium. Purpose To determine whether the MRI pattern of left atrial fibrosis is associated with the chronicity of AF. Materials and Methods This retrospective study included patients with AF who underwent LGE MRI between June 2017 and May 2018. The presence of left atrial LGE was assessed at nine left atrial segments; the extent was determined by the number of segments involved. According to the chronicity of AF, patients were separated into paroxysmal AF (PAF) and persistent AF (PeAF) groups. The location and extent of left atrial LGE were compared between PAF and PeAF by using the χ2 test and logistic regression analysis. Results Of the 195 patients (mean age, 55 years ± 10 [standard deviation], 161 men), 74 (38%) had PAF and 121 (62%) had PeAF. Of all patients, 114 (58.4%) had at least one left atrial LGE segment. The mean number of LGE segments was higher (1.4 ± 1.1 vs 0.6 ± 0.7, P = .002) in the PeAF group than in the PAF group. The incidence of LGE at the left inferior pulmonary vein (LIPV) antrum was higher in the PeAF group than in the PAF group (39.2% [29 of 74] vs 7.4% [nine of 121]; P < .001). In multivariable analysis, LGE at the LIPV antrum was independently associated with PeAF (odds ratio = 4.2; 95% confidence interval: 1.7, 10.5; P < .001). Conclusion The presence of fibrosis assessed with late gadolinium enhancement MRI of the left inferior pulmonary vein antrum was associated with persistent atrial fibrillation. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Almeida in this issue.

OBJECTIVE To investigate the accuracy of model-based iterative reconstruction (MIR) for volume measurement of part-solid nodules (PSNs) and solid nodules (SNs) in comparison with filtered back projection (FBP) or hybrid iterative reconstruction (HIR) at various radiation dose settings. MATERIALS AND METHODS CT scanning was performed for eight different diameters of PSNs and SNs placed in the phantom at five radiation dose levels (120 kVp/100 mAs, 120 kVp/50 mAs, 120 kVp/20 mAs, 120 kVp/10 mAs, and 80 kVp/10 mAs). Each CT scan was reconstructed using FBP, HIR, or MIR with three different image definitions (body routine level 1 [IMR-R1], body soft tissue level 1 [IMR-ST1], and sharp plus level 1 [IMR-SP1]; Philips Healthcare). The SN and PSN volumes including each solid/ground-glass opacity portion were measured semi-automatically, after which absolute percentage measurement errors (APEs) of the measured volumes were calculated. Image noise was calculated to assess the image quality. RESULTS Across all nodules and dose settings, the APEs were significantly lower in MIR than in FBP and HIR (all p < 0.01). The APEs of the smallest inner solid portion of the PSNs (3 mm) and SNs (3 mm) were the lowest when MIR (IMR-R1 and IMR-ST1) was used for reconstruction for all radiation dose settings. (IMR-R1 and IMR-ST1 at 120 kVp/100 mAs, 1.06 ± 1.36 and 8.75 ± 3.96, p < 0.001; at 120 kVp/50 mAs, 1.95 ± 1.56 and 5.61 ± 0.85, p = 0.002; at 120 kVp/20 mAs, 2.88 ± 3.68 and 5.75 ± 1.95, p = 0.001; at 120 kVp/10 mAs, 5.57 ± 6.26 and 6.32 ± 2.91, p = 0.091; at 80 kVp/10 mAs, 5.84 ± 1.96 and 6.90 ± 3.31, p = 0.632). Image noise was significantly lower in MIR than in FBP and HIR for all radiation dose settings (120 kVp/100 mAs, 3.22 ± 0.66; 120 kVp/50 mAs, 4.19 ± 1.37; 120 kVp/20 mAs, 5.49 ± 1.16; 120 kVp/10 mAs, 6.88 ± 1.91; 80 kVp/10 mAs, 12.49 ± 6.14; all p < 0.001). CONCLUSION MIR was the most accurate algorithm for volume measurements of both PSNs and SNs in comparison with FBP and HIR at low-dose as well as standard-dose settings. Specifically, MIR was effective in the volume measurement of the smallest PSNs and SNs.

Atrial fibrillation (AF) is the most common arrhythmia associated with the risk of morbidity and mortality in clinical patients. AF is considered as an arrhythmia type that develops and progresses through close connection with cardiac structural arrhythmogenic substrates. Since the introduction of catheter ablation-mediated electrical isolation of arrhythmogenic substrates, cardiac imaging indicates improved treatment outcome and prognosis with appropriate candidate selection, ablation catheter guidance, and post-ablation follow-up. Currently, cardiac computed tomography (CCT) and cardiovascular magnetic resonance (CMR) imaging are essential in the case management of AF at both pre-and post-procedural stages of catheter ablation. In this review, we discuss the roles and technical considerations of CCT and CMR imaging in the management of patients with AF undergoing catheter ablation.

To explore the importance of quantitative characteristics of dual-energy CT (DECT) between pulmonary metastasis and benign lung nodules in thyroid cancer. In this retrospective study, we identified 63 patients from our institution’s database with pathologically proven thyroid cancer who underwent DECT to assess pulmonary metastasis. Among these patients, 22 had 55 pulmonary metastases, and 41 had 97 benign nodules. If nodules showed increased iodine uptake on I-131 single-photon emission computed tomography-computed tomography or increased size in follow-up CT, they were considered metastatic. We compared the clinical findings and DECT parameters of both groups and performed a receiver operating characteristic analysis to evaluate the optimal cutoff values of the DECT parameters. Patients with metastases were significantly older than patients with benign nodules (p = 0.048). The DECT parameters of the metastatic nodules were significantly higher than those of the benign nodules (iodine concentration [IC], 5.61 ± 2.02 mg/mL vs. 1.61 ± 0.98 mg/mL; normalized IC [NIC], 0.60 ± 0.20 vs. 0.16 ± 0.11; NIC using pulmonary artery [NICPA], 0.60 ± 0.44 vs. 0.15 ± 0.11; slope of the spectral attenuation curves [λHU], 5.18 ± 2.54 vs. 2.12 ± 1.39; and Z-effective value [Zeff], 10.0 ± 0.94 vs. 8.79 ± 0.75; all p < 0.001). In the subgroup analysis according to nodule size, all DECT parameters of the metastatic nodules in all subgroups were significantly higher than those of the benign nodules (all p < 0.05). The cutoff values for IC, NIC, λHU, NICPA, and Zeff for diagnosing metastases were 3.10, 0.29, 3.57, 0.28, and 9.34, respectively (all p < 0.001). DECT parameters can help to differentiate metastatic and benign lung nodules in thyroid cancer. • DECT parameters can help to differentiate metastatic and benign lung nodules in patients with thyroid cancer. • DECT parameters showed a significant difference between benign lung nodules and lung metastases, even for nodules with diameters ≥ 3 mm and

INTRODUCTION Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients. Velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the association between radiofrequency catheter ablation (RFCA) and LAA hemodynamics measured by MRI. METHODS AND RESULTS Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.93 ± 32.92 and 72.00 ± 34.82 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 14.63 ± 40.67 vs. 30.03 ± 35.37; p

PURPOSE: To evaluate the feasibility of coronary iodine concentration (CIC) by using spectral CT in the assessment of the outcome of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). MATERIALS AND METHODS: In total, 50 consecutive patients underwent preprocedural coronary CT angiography with spectral CT prior to their staged PCI for CTO between June 2017 and July 2018. Iodine density maps, referred to as iodine-no-water maps throughout, with spectral CT provided the CIC at proximal CTO (CTO-CIC). Depending on the outcome of PCI, all CTO lesions were divided into two groups: failed PCI and successful PCI. The receiver operating characteristic curve was used to determine the cutoff values of CTO-CIC in the assessment of the outcome of PCI for CTO. RESULTS: Of the 50 CTO lesions in 50 patients, 34 (68%) and 16 (32%) were assigned to the successful PCI and failed PCI groups, respectively. The mean CTO-CIC was significantly less in the failed PCI group than in the successful PCI group (1.3 mg/mL ± 0.9 [standard deviation] vs 5.2 mg/mL ± 2.5; P < .001). A low CTO-CIC (≤ 2.5 mg/mL) predicted failed PCI with 87% sensitivity, 79% specificity, 79% positive predictive value, and 90% negative predictive value. At multivariable analysis, the low CTO-CIC was significantly associated with the failed PCI (odds ratio, 27.0; 95% confidence interval: 4.9, 147.6; P < .0001). CONCLUSION: The CTO-CIC determined by using spectral CT may be useful in the assessment of the outcome of staged PCI for CTO. See also the commentary by Rubinshtein and Blankstein in this issue. © RSNA, 2020

This study aimed to investigate the association between the degree of thoracic duct dilatation and the progression of chronic liver disease.In this cross-sectional and retrospective study, 179 patients (mean age, 60.9 years; 114 men) with chronic liver disease who underwent chest CT were enrolled. Dilatation of the left distal thoracic ducts (DTD) was measured and divided into the following 3 grades according to the maximum transverse diameter: grade 0, invisible thoracic duct; grade 1, visible duct with

OBJECTIVE To assess the effect of left atrial appendage (LAA) isolation on LAA emptying and left atrial (LA) function using cardiac MRI in patients who underwent successful catheter ablation of atrial fibrillation (AF). MATERIALS AND METHODS This retrospective study included 84 patients (mean age, 59 ± 10 years; 67 males) who underwent cardiac MRI after successful catheter ablation of AF. According to the electrical activity of LAA after catheter ablation, patients showed either LAA isolation or LAA normal activity. The LAA emptying phase (LAA-EP, in the systolic phase [SP] or diastolic phase), LAA emptying flux (LAA-EF, mL/s), and LA ejection fraction (LAEF, %) were evaluated by cardiac MRI. RESULTS Of the 84 patients, 61 (73%) and 23 (27%) patients showed LAA normal activity and LAA isolation, respectively. Incidence of LAA emptying in SP was significantly higher in LAA isolation (91% vs. 0%, p < 0.001) than in LAA normal activation. LAA-EF was significantly lower in LAA isolation (40.1 ± 16.2 mL/s vs. 80.2 ± 25.1 mL/s, p < 0.001) than in LAA normal activity. Furthermore, LAEF was significantly lower in LAA isolation (23.7% ± 11.2% vs. 31.1% ± 16.6%, p = 0.04) than in LAA normal activity. Multivariate analysis demonstrated that the LAA-EP was independent from LAEF (p = 0.01). CONCLUSION LAA emptying in SP may be a critical characteristic of LAA isolation, and it may adversely affect the LAEF after catheter ablation of AF.

Aspiration is defined as accidental entrance of foreign matter into the lower respiratory tract, and is a common event and can occur in healthy individuals. The type of aspiration-induced lung diseases depends on the quantity and nature of the aspirated material, the chronicity, and the host responses. Aspiration into the airways and lungs can cause a wide spectrum of lung diseases with various manifestations in adults. Diseases with predominantly airway manifestation include foreign body aspiration and diffuse aspiration bronchiolitis. Diseases with predominantly lung parenchymal manifestation include acute diseases such as aspiration pneumonia, aspiration pneumonitis, and near drowning, and chronic diseases such as chronic exogenous lipoid pneumonia and chronic interstitial lung disease. Definitive diagnosis of aspiration-induced lung diseases is challenging to make. Awareness of radiologic findings associated with these diseases is essential for accurate diagnosis and management of these diverse aspiration-induced lung diseases.

Many age-related morphologic changes are revealed in radiologic images of the chest in the elderly. We categorize the aging chest according to changes in the lung, airways, mediastinum, chest wall, and diaphragm. Changes in the lung include age-related alveolar hyperinflation, ground-glass opacity in basal dependent lungs, mosaic attenuation pattern, reticular densities in basal subpleural lungs, small nodule, air cyst, and apical cap. Changes in the airway include the tracheobronchial wall cartilage calcification, increased anterior-posterior diameter of the trachea, increased bronchoarterial ratio and bronchial wall thickness. Mediastinum changes include cardiac enlargement, coronary and cardiac valve/annulus calcification, aorta dilation and wall calcification, and excessive fat deposition. The chest wall shows decreased muscle mass, osteophytes, rib cartilage calcifications, and increased thoracic anterior-posterior diameter. The diaphragm changes include bulging contour, diaphragm defect, and esophageal hiatal hernia. Radiologists should therefore be aware of the age-related changes in the elderly chest. Differentiation between normal age-related changes and clinically significant disease is essential in the interpretation of chest radiologic images.

The goals of this study were to determine whether bone density measured using CT (CTBD) can show significant differences in bone loss according to smoking status and pack-years, and to examine the correlation between CTBD and bone mineral density when measured by dual-energy X-ray absorptiometry (DEXA-BMD) in males without chronic obstructive pulmonary disease (COPD). In this cross-sectional study, 1,011 males without airflow obstruction ≥50 years old were included. CTBD and DEXA-BMD were compared among groups with different smoking statuses. The correlation between CTBD and DEXA-BMD and the association of CTBD with pack-years were also investigated. CTBD of all vertebral bodies (VBs) and DEXA-BMD of all VBs without L1 showed significant differences among never, former, and current smokers. CTBD was significantly lowest in ≥30-pack-year smokers and was significantly lower in ≥30-pack-year smokers than in

Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dube syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

The complex fractioned atrial electrogram (CFAE) has been considered as the catheter ablation target of left atrium (LA) under persistent atrial fibrillation (PeAF). We evaluated the relation between the LA wall composition by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) and the CFAE in patients with PeAF. Forty-three patients underwent LGE-CMR and CFAE mapping before catheter ablation for PeAF. The LA wall substrates were classified into three: the fibrotic, intermediate, and normal substrates by using two thresholds of 2 standard deviation (2-SD) and 6-SD above the mean signal from the normal myocardium. For each of 12 preselected LA wall regions, the composition ratios (CRs) of fibrotic, indeterminate, and normal substrates were calculated as a percentage to the volume of LA wall region, and compared depending on the CFAE, respectively. The CR of normal substrate was significantly greater at the LA wall region with CFAE (52 ± 38% vs. 20 ± 28%, P0.01) than without CFAE. In contrast, the LA wall region with CFAE showed significantly lower CRs of intermediate substrate (39 ± 34% vs. 57 ± 31%, P0.01) and fibrotic substrate (7 ± 17% vs. 21 ± 24%, P0.01) than did the LA wall region without CFAE, respectively. Thus, the high CR (18%) of normal substrate predicted the CFAE at the corresponding LA wall region with 71% sensitivity and 62% specificity. In conclusion, the evaluation of LA wall normal substrate by LGE-CMR might be useful to predict the CFAE occurrence before catheter ablation of PeAF.

OBJECTIVE To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. MATERIALS AND METHODS A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. RESULTS In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 ± 0.9%, and 1.7 ± 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 ± 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 ± 5.3%), with an IVV of 13.1 ± 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. CONCLUSION The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

Although hydrochloric acid (HCl) inhalation-induced lung injury occurs often, its imaging findings are not well-known. In the present study, we retrospectively reviewed imaging studies and clinical data from seven patients who were treated for HCl inhalation, after estimation of in vitro toxicological effects of several strong acids in human lung cells. Cell death in the lungs which increased with prolonged incubation time and concentration of HCl, was predominantly associated with the apoptosis, compared with the necrosis. HCl inhalation-induced lung injuries showed three patterns of computed tomography (CT) findings: ground glass opacities with interstitial thickening suggesting permeability pulmonary edema, irregular linear abnormalities, and centrilobular nodules. These abnormalities tended to improve within 1 week of exposure, leaving only minimal changes. These patterns of imaging illustrations, according to the time frame, may help physicians and radiologists comprehend the pathophysiology of these injuries, and to predict the prognosis of HCl inhalation-induced lung injury.

Purpose To investigate the relationship between left atrial appendage (LAA) blood flow determined with cardiac magnetic resonance (MR) imaging and left atrial pressure (LAP) estimated from invasive catheter measurements in patients with atrial fibrillation (AF). Materials and Methods This retrospective study was approved by the institutional review board, and patients provided written informed consent. Seventy-seven patients with AF (mean age, 57.8 years ± 9.8; range, 31-76 years) underwent cardiac MR imaging and catheter-based measurement of LAP, sequentially. Velocity-encoded (VENC) cardiac MR imaging was performed perpendicular to the ostium of the LAA. The maximum blood flux (in milliliters per second) from the LAA to the left atrium (LA) as determined with VENC MR imaging was defined as LAA emptying. Patients were classified into two groups: those with elevated LAP (peak LAP ≥19 mm Hg) and those with nonelevated LAP (peak LAP19 mm Hg). Receiver operating characteristic curves were used to determine the cut-off values of LAA emptying in the assessment of the LAP status. Results LAA emptying showed a significantly inverse relationship (P.01) with the peak LAP. Patients with elevated LAP showed significantly less LAA emptying than did patients with nonelevated LAP (mean, 39.3 mL/sec ± 13.7 vs 61.2 mL/sec ± 20.7, respectively; P.01). In the assessment of elevated LAP with use of VENC MR imaging in normal sinus rhythm, the LAA emptying cut-off value of 47 mL/sec had a sensitivity of 75.0%, specificity of 87.5%, positive predictive value of 66.6%, and negative predictive value of 91.3%. At multivariate analysis, the odds ratio of low LAA emptying (47 mL/sec) was independently associated with elevated LAP. Conclusion Evaluation of LAA emptying with use of VENC MR imaging is helpful for assessing the LAP status of patients with AF.

OBJECTIVE To investigate the relationship between a chronic obstructive pulmonary disease (COPD) candidate gene, based on a genomewide association study, and computed tomographic (CT) quantitative analysis; and to find a phenotype in the COPD candidate FAM13A gene. MATERIALS AND METHODS This study was conducted in subclinical male smokers between 2 groups with matched age and smoking status; 162 subjects (mean age, 58 years) with risk (CTGA, n = 85) and reference (TCAG, n = 77) diplotypes replicated through genomewide association study underwent chest CT for quantitative analysis of lungs and airways. We analyzed the measures in both the risk and reference groups using a 2-sample t test. RESULTS Subjects with the risk CTGA diplotype had significantly higher total lung volume and emphysema index than the reference TCAG diplotype (P = 0.04). Mean lung density was significantly lower (P < 0.05) in the risk group. However, in the analysis of airways, wall area, luminal area, wall and lumen area ratio, and mean lung density on expiratory and inspiratory phases, no significant differences between the 2 groups were seen. CONCLUSIONS There is a strong relationship between CT quantitative analysis and the COPD candidate gene. Furthermore, the CTGA diplotype was associated with emphysema among the phenotypes of COPD.

In patients with atrial fibrillation (AF), left atrial (LA) fibrosis is an important component of the arrhythmogenic substrate and is related to LA dysfunciton, which contribute the development of thromboembolism. However, there is little known relations among LA fibrosis, functional change and risk

Purpose To demonstrate the relationship between epicardial fat accumulation and left atrial reverse remodeling by cardiac multi-detector CT (MDCT) after catheter ablation of atrial fibrillation (AF). Materials and Methods Seventy-six patients underwent cardiac MDCT before and after catheter ablation of AF. Left atrial volume (LAV) and epicardial fat volume (EFV) were measured. LAV and EFV before and after catheter ablation of AF were respectively compared and the change percentages (CPs) were evaluated. Results The LAV after catheter ablation of AF was significantly less than the baseline LAV (107.5 ± 50.2 mL vs. 144.9 ± 62.6 mL, p < 0.001). The EFV after catheter ablation of AF was significantly greater than the baseline EFV (105.0 ± 35.6 mL vs. 90.1 ± 31.9 mL, p < 0.001). Mean CPs of LAV and EFV were -23.3% ± 20.8% and 15.9% ± 20.9%, respectively. There was a significantly negative relationship between the CPs of LAV and EFV (R = -0.53, p < 0.001). Conclusion Catheter ablation of AF may result in a reduction in LAV and an increase in EFV. Left atrial reverse remodeling with a reduction in LAV may be associated with epicardial fat accumulation in patients who undergo catheter ablation of AF.

To compare cardiac magnetic resonance (CMR) quantifications of left atrium (LA) function and left atrial appendage (LAA) emptying depending on the presence of LA spontaneous echogenic contrast (LA-SEC) on transesophageal echocardiography (TEE) in patients with atrial fibrillation (AF). A total of 48 patients with AF underwent sequential CMR examination and TEE in preparation for catheter ablation. The CMR protocol included cine and velocity encoding (VENC) sequences for evaluation of both LA function and LAA emptying. The peak blood velocity of LAA just before left ventricle systole was defined as the LAA emptying velocity (LAA-EV). Depending on the presence of LA-SEC on TEE, patients were divided into two groups, the SEC group (n = 15) and the non-SEC group (n = 33). Mean LAA-EV was significantly greater in the non-SEC group than in the SEC group (54.5 ± 24.8 ml/s vs. 26.0 ± 22.6 ml/s, P

To evaluate the incremental value of diffusion-weighted imaging (DWI) in combination with T2-weighted imaging to detect low (Gleason score, ≤ 6) and intermediate or high risk (Gleason score, ≥ 7) prostate cancer.Fifty-one patients who underwent MRI before prostatectomy were evaluated. Two readers independently scored the probability of tumour in eight regions of prostate on T2-weighted images (T2WI) and T2WI combined with apparent diffusion coefficient (ADC) maps. Data were divided into two groups--low risk and intermediate or high risk prostate cancer--and correlated with histopathological results. Diagnostic performance parameters, areas under the receiver-operating characteristic curve (AUCs) and interreader agreement were calculated.For both readers, AUCs of combined T2WI and ADC maps were greater than those of T2WI in intermediate or high risk (reader 1, 0.887 vs. 0.859; reader 2, 0.732 vs 0.662, P0.05) prostate cancers, but not in low risk (reader 1, 0.719 vs 0.725; reader 2, 0.685 vs. 0.680, P0.05) prostate cancers. Weighted κ value of combined T2WI and ADC maps was 0.689.The addition of DWI to T2-weighted imaging improves the accuracy of detecting intermediate or high risk prostate cancers, but not for low risk prostate cancer detection.• Gleason scores influence diagnostic performance of MRI for prostate cancer detection. • Addition of DWI does not improve low risk prostate cancer detection. • Combined T2WI and DWI may help select intermediate or high risk patients.

To determine the relationship between clinical impairment and MRI findings in patients with adhesive capsulitis. Contrast-enhanced MRI of 97 patients with a clinical diagnosis of adhesive capsulitis (AC) were retrospectively reviewed. Specific MRI criteria, including thickness and gadolinium enhancement of the joint capsule in the axillary recess and subcoracoid fat obliteration in the rotator interval, were correlated with limited range of motion (ROM) and pain. Other variables considered in this study were rotator cuff pathology, arm dominance, diabetes mellitus, age, and gender. Statistical analysis was performed using logistic and linear regression analysis. Thickening of the joint capsule in the axillary recess correlated with limited external rotation (p

Tuberculous destroyed lung (TDL) is diagnosed by a clear past history of tuberculosis with findings of parenchymal destruction verified by chest X-ray. Despite the resultant deterioration of lung function and quality of lives seen in TDL patients, the exact mechanism or characteristics of pulmonary function worsening have not been clearly studied. We investigated the feature of respiratory impairment of TDL patients, and studied whether extent of destroyed lung measured with chest CT has any correlation with routine lung function. To evaluate the degree of destruction, the Goddard classification scoring system was modified into a novel scoring system (destroyed lung score, (DLS)) with a score from 0 to 4. Twenty-five subjects were enrolled. TDL predominantly manifested as an obstructive pattern (64%, 16/25). Median value of DLS of the entire lung was 2.6 (1.7–3.9). Absolute values of FEV1 and FVC were both negatively associated with DLS (r=-0.78,P=0.001, andr=-0.61,P=0.021). Percentage of predicted value of FEV1and FVC were also negatively associated with DLS (r=-0.62,P=0.019, andr=-0.76,P=0.002). Our study shows that lung function of TDL patients were notably correlated with the extent of destroyed lung measured with chest CT scan.

A 56-year-old man with symptomatic atrial fibrillation (AF) was referred to our arrhythmia center for pulmonary vein isolation by catheter ablation. The patient underwent routine transesophageal echocardiography (TEE) and cardiac magnetic resonance (MR) examination before the catheter ablation. The cardiac MR examination consisted of time-resolved (4-dimensional) contrast-enhanced MR angiography (TR-MRA), cine imaging with steady-state free precession, and 3-dimensional (3D) late gadolinium enhancement (3D-LGE) sequences. In assessments of cardiac function and thrombus (Figure 1), the TEE image demonstrated the nodular structure adhering to the interatrial septum of right atrium (RA). The cine image revealed a thin membrane dividing the RA into 2 chambers. The proximal and distal chambers of RA were connected to the inferior vena cava (IVC) and superior vena cava (SVC), respectively. The TR-MRA (Figure 2) showed a strongly enhanced distal chamber of RA with …

Objective To evaluate the accuracy of emphysema volume (EV) and airway measurements (AMs) produced by various iterative reconstruction (IR) algorithms and virtual monoenergetic images (VME) at both low- and standard-dose settings. Materials and Methods Computed tomography (CT) images were obtained on phantom at both low- (30 mAs at 120 kVp) and standard-doses (100 mAs at 120 kVp). Each CT scan was reconstructed using filtered back projection, hybrid IR (iDose4; Philips Healthcare), model-based IR (IMR-R1, IMR-ST1, IMR-SP1; Philips Healthcare), and VME at 70 keV (VME70). The EV of each air column and wall area percentage (WA%) of each airway tube were measured in all algorithms. Absolute percentage measurement errors of EV (APEvol) and AM (APEWA%) were then calculated. Results Emphysema volume was most accurately measured in IMR-R1 (APEvol in low-dose, 0.053 ± 0.002; APEvol in standard-dose, 0.047 ± 0.003; all p < 0.001) and AM was the most accurate in IMR-SP1 on both low- and standard-doses CT (APEWA% in low-dose, 0.067 ± 0.002; APEWA% in standard-dose, 0.06 ± 0.003; all p < 0.001). There were no significant differences in the APEvol of IMR-R1 between low- and standard-doses (all p > 0.05). VME70 showed a significantly higher APEvol than iDose4, IMR-R1, and IMR-ST1 (all p < 0.004). VME70 also showed a significantly higher APEWA% compared with the other algorithms (all p < 0.001). Conclusion IMR was the most accurate technique for measurement of both EV and airway wall thickness. However, VME70 did not show a significantly better accuracy compared with other algorithms.

Purpose To compare the prevalence and clinical significance of incidental extracardiac findings at cardiac CT angiography (CCTA) with precontrast low-dose whole thoracic scan (LDCT) and ECG-gated CCTA. Materials and Methods We reviewed 254 patients who underwent CCTA. All participants first underwent LDCT to determine a range for CCTA and to screen unrecognized extracardiac lesions. CCTA was reconstructed with a small field of view of the heart. Clinically significant extracardiac findings were defined as abnormalities requiring further diagnostic work up, therapeutic intervention, or follow-up. Results On LDCT, 285 extracardiac findings were detected in 62.6% patients; on CCTA, 18 findings in 7% patients. Among these, 66 findings in 20.4% patients were considered clinically significant on LDCT, and 4 findings in 1.6% patients on CCTA. Conclusion Clinically significant extracardiac findings are common in patients undergoing CCTA with a considerable number of extracardiac findings being detected only on LDCT. We advise performing whole thorax LDCT prior to CCTA.

The introduction of thin-section computed tomography (CT) has improved the diagnosis of bronchiolitis and contributed to establish bronchiolitis as an important part of pulmonary medicine. The histopathologic groups of bronchiolitis include cellular bronchiolitis, diffuse panbronchiolitis, follicular bronchiolitis, respiratory bronchiolitis, proliferative bronchiolitis, constrictive bronchiolitis, and mineral dust airway disease. Bronchiolitis can be readily identified and may lead to characteristic findings on thin-section CT. Various bronchiolitis manifests as one or a combination of 3 main patterns in thin-section CT: centrilobular nodules and branching densities, ground-glass attenuation and consolidation, and low attenuation and mosaic perfusion pattern.

Extraskeletal Ewing's sarcoma (EES) is a branch of neuroectodermal tumor (PNET), which is very rare soft tissue sarcoma. We report a case of EES/PNET arising is the lung of a 67-yr-old man. Computed tomography, bone scintigraphy, and positron emission tomography confirmed the mass to have a primary pulmonary origin. The mass showed positive reactivity in the Periodic Acid Schiff (PAS) stain and MIC-2 immunoreactivity in immunohistochemical stain. Fluorescence in situ hybridization (FISH) was performed, which revealed an EWSR1 (Ewing sarcoma breakpoint region 1) 22q12 rearrangement. The diagnosis was confirmed both pathologically and genetically. The mass lesion was resected, and the patient is currently undergoing chemotherapy.

To evaluate the left distal thoracic duct (DTD) in the lower neck area by using contrast-enhanced chest computed tomography (CT) in patients with liver cirrhosis (LC).In 156 consecutive subjects who performed the contrast-enhanced chest CT, examinations were retrospectively reviewed. The diameters of the left DTD were measured by using CT. Depending on the diameter of the left DTD, the left DTD configurations were classified into four grades: grade 0 (no identification of DTD), grade I (diameter5mm), grade II (diameters ≥5mm and10mm), and grade III (diameter ≥10mm). Depending on the liver status, all 156 subjects were divided into three groups: (a) noncirrhotic liver group (n=55), (b) compensated LC group (n=88), and (c) decompensated LC group (n=13).Among the 156 left DTD configurations, 81 (52%), 60 (39%), 10 (6%), and only 4 (3%) were assigned to the grade 0, I, II, and III, respectively. The noncirrhotic liver group included 45 (82%) grade 0 and 10 (18%) grade I subjects. The compensated LC group included 37 (42%) grade 0, 50 (57%) grade I, and 1 (1%) grade II subjects. In contrast, the decompensated LC group included 9 (69%) grade II and 4 (31%) grade III subjects.When reviewed the contrast-enhanced chest CT, the left DTD can be identified more frequently in subjects with LC than in those with noncirrhotic liver. Furthermore, the degree of left DTD dilation may be associated with the severity of LC.

To compare the diagnostic performance of digital tomosynthesis (DTS) and chest radiography for detecting airway abnormalities, using computed tomography (CT) as a reference. We evaluated 161 data sets from 149 patients (91 with and 70 without airway abnormalities) who had undergone radiography, DTS, and CT to detect airway problems. Radiographs and DTS were evaluated to localize and score the severity of the airway abnormalities, and to score the image quality using CT as a reference. Receiver operating characteristics (ROC), McNemar’s test, weighted kappa, and the paired t-test were used for statistical analysis. The sensitivity of DTS was higher (reader 1, 93.51 %; reader 2, 94.29 %) than chest radiography (68.83 %; 71.43 %) in detecting airway lesions. The diagnostic accuracy of DTS (90.91 %; 94.70 %) was also significantly better than that of radiography (78.03 %; 82.58 %, all p

We compared digital tomosynthesis (TOMO) and chest CT in terms of assessing the sizes of nodules located in zones where evaluation by simple radiography is limited.A total of 48 images comprising phantom nodules of four sizes in six different locations were used. Nodule size measurement errors for measurements using TOMO and CT images compared with the actual size from each observer were calculated. The inter- and intraobserver repeatability of the measured values and the agreement between the two techniques were assessed using the method described by Bland and Altman.The mean measurement errors for all of the nodules and four observers were -0.84 mm [standard deviation (SD), 0.60 mm] on TOMO and -0.18 mm (SD, 0.71 mm) on CT images. The mean measurement errors for the different observers ranged from -1.11 to -0.55 mm for TOMO and from -0.39 to 0.08 mm for CT. Assessing the agreement between nodule size measurements using TOMO and CT resulted in mean measurement errors of -0.65 mm, with a 95% limit of agreement of -2.53 to 1.22 mm for comparison of TOMO with CT.Our results suggest that nodule sizes obtained using TOMO and chest CT are comparable, even for nodules located in areas where the size measurement is limited on simple radiography.TOMO and CT can be used interchangeably, even for nodules located in a blind area on simple radiography.