CT-guided percutaneous transthoracic needle biopsy for anterior mediastinal lymphoma: the role of PET/CT.

BACKGROUND: Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is not recommended as the diagnostic modality of choice for anterior mediastinal lymphoma, despite its advantages of minimal invasiveness and easy accessibility. PURPOSE: To identify the modifiable risk factors for non-diagnostic results from CT-guided PTNB for anterior mediastinal lymphoma. MATERIAL AND METHODS: This retrospective study identified CT-guided PTNB for anterior mediastinal lesions diagnosed as lymphoma between May 2007 and December 2021. The diagnostic sensitivity and complications were investigated. The appropriateness of PTNB targeting was evaluated using positron emission tomography (PET)/CT and images from intra-procedural CT-guided PTNB. Targeting was considered inappropriate when the supposed trajectory of the cutting needle was within a region of abnormally low metabolism. The risk factors for non-diagnostic results were determined using logistic regression analysis. RESULTS: A total of 67 PTNBs in 60 patients were included. The diagnostic sensitivity for lymphoma was 76.1% (51/67), with an immediate complication rate of 4.5% (3/67). According to the PET/CT images, PTNB targeting was inappropriate in 10/14 (71.4%) of the non-diagnostic PTNBs but appropriate in all diagnostic PTNBs (P <0.001). Inappropriate targeting was the only significant risk factor for non-diagnostic results (odds ratio = 203.69; 95% confidence interval = 8.17-999.99; P = 0.001). The number of specimen acquisitions was not associated with non-diagnostic results (P = 0.40). CONCLUSIONS: Only inappropriate targeting of the non-viable portion according to PET/CT was an independent risk factor for non-diagnostic results. Acquiring PET/CT scans before biopsy and targeting the viable portion on PET/CT may help improve the diagnostic sensitivity of PTNB.

Evaluation of retrieval accuracy and visual similarity in content-based image retrieval of chest CT for obstructive lung disease.

The aim of our study was to assess the performance of content-based image retrieval (CBIR) for similar chest computed tomography (CT) in obstructive lung disease. This retrospective study included patients with obstructive lung disease who underwent volumetric chest CT scans. The CBIR database included 600 chest CT scans from 541 patients. To assess the system performance, follow-up chest CT scans of 50 patients were evaluated as query cases, which showed the stability of the CT findings between baseline and follow-up chest CT, as confirmed by thoracic radiologists. The CBIR system retrieved the top five similar CT scans for each query case from the database by quantifying and comparing emphysema extent and size, airway wall thickness, and peripheral pulmonary vasculatures in descending order from the database. The rates of retrieval of the same pairs of query CT scans in the top 1-5 retrievals were assessed. Two expert chest radiologists evaluated the visual similarities between the query and retrieved CT scans using a five-point scale grading system. The rates of retrieving the same pairs of query CTs were 60.0% (30/50) and 68.0% (34/50) for top-three and top-five retrievals. Radiologists rated 64.8% (95% confidence interval 58.8-70.4) of the retrieved CT scans with a visual similarity score of four or five and at least one case scored five points in 74% (74/100) of all query cases. The proposed CBIR system for obstructive lung disease integrating quantitative CT measures demonstrated potential for retrieving chest CT scans with similar imaging phenotypes. Further refinement and validation in this field would be valuable.

Deep Learning for Automated Triaging of Stable Chest Radiographs in a Follow-up Setting.

Background Most artificial intelligence algorithms that interpret chest radiographs are restricted to an image from a single time point. However, in clinical practice, multiple radiographs are used for longitudinal follow-up, especially in intensive care units (ICUs). Purpose To develop and validate a deep learning algorithm using thoracic cage registration and subtraction to triage pairs of chest radiographs showing no change by using longitudinal follow-up data. Materials and Methods A deep learning algorithm was retrospectively developed using baseline and follow-up chest radiographs in adults from January 2011 to December 2018 at a tertiary referral hospital. Two thoracic radiologists reviewed randomly selected pairs of "change" and "no change" images to establish the ground truth, including normal or abnormal status. Algorithm performance was evaluated using area under the receiver operating characteristic curve (AUC) analysis in a validation set and temporally separated internal test sets (January 2019 to August 2021) from the emergency department (ED) and ICU. Threshold calibration for the test sets was conducted, and performance with 40% and 60% triage thresholds was assessed. Results This study included 3 304 996 chest radiographs in 329 036 patients (mean age, 59 years ± 14 [SD]; 170 433 male patients). The training set included 550 779 pairs of radiographs. The validation set included 1620 pairs (810 no change, 810 change). The test sets included 533 pairs (ED; 265 no change, 268 change) and 600 pairs (ICU; 310 no change, 290 change). The algorithm had AUCs of 0.77 (validation), 0.80 (ED), and 0.80 (ICU). With a 40% triage threshold, specificity was 88.4% (237 of 268 pairs) and 90.0% (261 of 290 pairs) in the ED and ICU, respectively. With a 60% triage threshold, specificity was 79.9% (214 of 268 pairs) and 79.3% (230 of 290 pairs) in the ED and ICU, respectively. For urgent findings (consolidation, pleural effusion, pneumothorax), specificity was 78.6%-100% (ED) and 85.5%-93.9% (ICU) with a 40% triage threshold. Conclusion The deep learning algorithm could triage pairs of chest radiographs showing no change while detecting urgent interval changes during longitudinal follow-up. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Czum in this issue.

MuSiC-ViT: A multi-task Siamese convolutional vision transformer for differentiating change from no-change in follow-up chest radiographs.

A major responsibility of radiologists in routine clinical practice is to read follow-up chest radiographs (CXRs) to identify changes in a patient's condition. Diagnosing meaningful changes in follow-up CXRs is challenging because radiologists must differentiate disease changes from natural or benign variations. Here, we suggest using a multi-task Siamese convolutional vision transformer (MuSiC-ViT) with an anatomy-matching module (AMM) to mimic the radiologist's cognitive process for differentiating baseline change from no-change. MuSiC-ViT uses the convolutional neural networks (CNNs) meet vision transformers model that combines CNN and transformer architecture. It has three major components: a Siamese network architecture, an AMM, and multi-task learning. Because the input is a pair of CXRs, a Siamese network was adopted for the encoder. The AMM is an attention module that focuses on related regions in the CXR pairs. To mimic a radiologist's cognitive process, MuSiC-ViT was trained using multi-task learning, normal/abnormal and change/no-change classification, and anatomy-matching. Among 406 K CXRs studied, 88 K change and 115 K no-change pairs were acquired for the training dataset. The internal validation dataset consisted of 1,620 pairs. To demonstrate the robustness of MuSiC-ViT, we verified the results with two other validation datasets. MuSiC-ViT respectively achieved accuracies and area under the receiver operating characteristic curves of 0.728 and 0.797 on the internal validation dataset, 0.614 and 0.784 on the first external validation dataset, and 0.745 and 0.858 on a second temporally separated validation dataset. All code is available at https://github.com/chokyungjin/MuSiC-ViT.

Efficacy and safety of transcatheter arterial embolization for hemodynamically unstable bleeding after percutaneous transthoracic needle biopsy.

PURPOSE: To evaluate the safety and efficacy of transcatheter arterial embolization (TAE) in controlling hemodynamically unstable bleeding following a percutaneous transthoracic needle biopsy (PTNB). METHODS: A total of seven patients (four men and three women; mean age, 62 ± 12 years) who received TAE for post-PTNB bleeding between May 2007 and March 2022 were included. The observed types of bleeding were hemothorax (n = 3), hemoptysis (n = 2), and a combination of both (n = 2). In patients with active bleeding, the technical success of TAE was defined as superselective embolization of the target artery with no active bleeding visible on post-TAE angiography. Clinical success was defined as sustained cessation of bleeding without hemodynamic instability, requirement of repeat TAE, or the need for post-TAE hemostatic surgery during the initial admission. The metrics analyzed included technical and clinical success rates, complications, and 30-day mortality. RESULTS: All seven patients achieved technical success, with a clinical success rate of 86% (6/7). Six patients were discharged alive, while one patient died of respiratory failure accompanied by hemothorax 19 days post-biopsy. The angiographic findings associated with bleeding were contrast media extravasation or pseudoaneurysm (n = 3) and vascular hypertrophy with tortuosity (n = 2). The implicated bleeding arteries included the intercostal artery (n = 2), bronchial artery (n = 2), and internal thoracic artery (n = 1). In two cases, no clear bleeding foci were identified; nonetheless, prophylactic embolization was performed on the right intercostal artery (n = 1) and right intercostobronchial trunk (n = 1). The embolic agents utilized included microcoils (n = 1), gelatin sponge particles (n = 2), polyvinyl alcohol (PVA) with gelatin sponge particles (n = 1), PVA with microcoils (n = 1), microcoils with gelatin sponge particles (n = 1), and microcoils with n-butyl-2-cyanoacrylate and gelatin sponge particles (n = 1). The 30-day mortality rate was 14% (1/7). No ischemic complications related to TAE were observed. CONCLUSION: The study suggests that TAE is safe and effective for controlling hemodynamically unstable bleeding following a PTNB.

Air embolism in CT-guided transthoracic needle biopsy: emphasis on pulmonary vein injury.

OBJECTIVE: To assess whether pulmonary vein injury is detectable on CT and associated with air embolism after percutaneous transthoracic needle biopsy (PTNB) in a tertiary referral hospital. METHODS: Between January 2012 and November 2021, 11,691 consecutive CT-guided PTNBs in 10,685 patients were retrospectively evaluated. Air embolism was identified by reviewing radiologic reports. Pulmonary vein injury was defined as the presence of the pulmonary vein in the needle pathway or shooting range of the cutting needle with the presence of parenchymal hemorrhage. The association between pulmonary vein injury and air embolism was assessed using logistic regression analysis in matched patients with and without air embolism with a ratio of 1:4. RESULTS: A total of 27 cases of air embolism (median age, 67 years; range, 48-80 years; 24 men) were found with an incidence of 0.23% (27/11,691). Pulmonary vein injury during the procedures was identifiable on CT in 24 of 27 patients (88.9%), whereas it was 1.9% (2/108) for matched patients without air embolism The veins beyond the target lesion (70.8% [17/24]) were injured more frequently than the veins in the needle pathway before the target lesion (29.2% [7/24]). In univariable and multivariable analyses, pulmonary vein injury was associated with air embolism (odds ratio, 485.19; 95% confidence interval, 68.67-3428.19, p <.001). CONCLUSION: Pulmonary vein injury was detected on CT and was associated with air embolism. Avoiding pulmonary vein injury with careful planning of the needle pathway on CT may reduce air embolism risk. KEY POINTS: • Pulmonary vein injury during CT-guided biopsy was identifiable on CT in most of the patients (88.9% [24/27]). • The veins beyond the target lesion (70.8% [17/24]) were injured more frequently than the veins in the needle pathway before the target lesion (29.2% [7/24]). • Avoiding the distinguishable pulmonary vein along the pathway or shooting range of the needle on CT may reduce the air embolism risk.

Preoperative electromagnetic navigation bronchoscopy-guided one-stage multiple-dye localization for resection of subsolid nodules: A single-center pilot study.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB)-guided transbronchial dye marking and video-assisted thoracoscopic surgery (VATS) is an emerging technique that enables successful resection of multiple small subsolid pulmonary nodules. The aim of this study was to evaluate the accuracy and safety of preoperative ENB-guided transbronchial multiple dye localization for VATS resection of subsolid pulmonary nodules. METHODS: As a single-center pilot study, we recruited patients with at least two small or subsolid pulmonary nodules. Multiple-dye localization was performed by intraoperative ENB-guided transbronchial injection of an indigo carmine dye. The patients underwent VATS for sublobar resection immediately after localization. The accuracy of ENB-guided dye marking was checked. RESULTS: ENB-guided one-stage multiple dye localization was conducted for 18 pulmonary nodules in seven patients between September 2018 and December 2019. The mean diameter of the pulmonary nodules was 9.3 mm (range, 4-18) and the mean distance from the pleura to pulmonary nodule was 6 mm (range, 1-17 mm). ENB-guided transbronchial multiple dye localization was successfully performed in 94.4% (17/18), and the accuracy of ENB-guided dye marking was 88.2% (15/17). When two nodules were not seen in intraoperative fields, anatomical sublobar resection was performed. There was no conversion to thoracotomy and operative mortalities. Among the seven patients, only one patient showed mild intrabronchial bleeding but stopped spontaneously. The changes in lung function after multiple wedge resections (-1.6% to 24.8%) were tolerable level. CONCLUSIONS: ENB-guided one-stage transbronchial dye localization showed accurate and safe intraoperative identification of multiple subsolid pulmonary nodules. A large scale prospective clinical study is warranted.

Diagnostic Performance of Electromagnetic Navigation Bronchoscopy-Guided Biopsy for Lung Nodules in the Era of Molecular Testing.

Electromagnetic navigation bronchoscopy (ENB) is an emerging technique used to evaluate peripheral lung lesions. The aim of this study was to determine the diagnostic yield, safety profile, and adequacy of specimens obtained using ENB for molecular testing. This single-center, prospective pilot study recruited patients with peripheral pulmonary nodules that were not suitable for biopsy via percutaneous transthoracic needle biopsy methods. The possibility of molecular testing, including epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and programmed death ligand 1 (PD-L1), was identified with non-small cell lung cancer (NSCLC) tissue obtained using ENB. ENB-guided biopsy was performed on 30 pulmonary nodules in 30 patients. ENB-guided biopsy was successfully performed in 96.6% (29/30) of cases, but one case failed to approach the target lesion. The diagnostic accuracy of ENB-guided biopsy was 68.0% (17/25). Biopsy-related pneumothorax occurred in one patient and there was no major bleeding or deaths related to the procedure. Among 13 patients diagnosed with NSCLC, molecular testing was successfully performed in 92.3% (12/13). ENB-guided biopsy demonstrated acceptable accuracy and excellent sample adequacy, with a high possibility of achieving molecular testing and a good safety profile to evaluate peripheral pulmonary nodules, even when the percutaneous approach was difficult and/or dangerous.

Diagnostic yield and safety of biopsy guided by electromagnetic navigation bronchoscopy for high-risk pulmonary nodules.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB) is a useful method to obtain tissue for peripheral lung nodules. We aimed to understand the diagnostic yield and safety profile in high-risk pulmonary nodules that cannot be accessed by percutaneous transthoracic needle biopsy. METHODS: In this single-center retrospective study, we reviewed patients who underwent ENB for high-risk pulmonary nodules. All procedures were performed under moderate sedation using intravenous midazolam and fentanyl. RESULTS: A total of 100 pulmonary nodules in 90 patients were subjected to ENB between October 2018 and May 2020. The median age of the study population was 66 (59-73). The mean diameter of the lung nodules was 27.9 mm. The diagnostic yield of ENB-guided biopsy was 53.0%. Although the nodule size (odds ratio: 1.055, p = 0.007) and positive bronchus sign (odds ratio: 2.918, p = 0.020) were associated with the diagnostic yield during univariate analysis, nodule size was the only independent variable on the multivariable analysis. Interestingly, the diagnostic yield showed an upward trend after 60 cases, from 45%-65%. Procedure-related complications were reported in 16 cases; among these, pneumothorax occurred in three cases, and four cases experienced moderate bleeding. No instance of major bleeding or death was linked to ENB-guided biopsy. CONCLUSION: ENB-guided biopsy for high-risk pulmonary nodules demonstrated an acceptable diagnostic yield and good safety profile. Moreover, the diagnostic yield was associated with nodule size and procedure experience.

Three-Dimensional Computed Tomographic Analysis of Normal and Aneurysmal Aortic Roots: Is There a Specific Geometric Pattern in the Aortic Root?

Current knowledge of the aortic root geometric anatomy and its surgical implications remain limited. We analyzed multiple predefined parameters of the aortic root to increase our understanding of the geometric changes that occur in normal and aneurysmal transformations. Between November 2003 and September 2015, the aortic roots of 107 healthy subjects (control group) and 105 annuloaortic ectasia (AAE) patients (AAE group) were analyzed using multiplanar reformatted computed tomographic images. The intercommissural distance (ICD), sinus width (SW), and sinus volume (SV) of the left (LCS), right (RCS), and noncoronary sinuses (NCS) of Valsalva were adopted as study parameters. In the control group, all study parameters of the LCS were smaller than those of the RCS and the NCS. In the AAE group, all parameters of the LCS were significantly smaller than those of the RCS or NCS, but the RCS and NCS parameters were similar. Proportionately less LCS enlargement relative to either the RCS or NCS was observed in root aneurysm(AAE group) than in the control group. We observed a distinct aortic root geometric pattern which was characterized by the LCS being smaller than either the RCS or NCS, while the latter were similar. This geometric configuration was significantly accentuated in AAE patients due to the greater disproportionate disparity in the LCS relative to either the RCS or NCS than in the roots of normal control subjects. Clin. Anat. 32:117-123, 2019. © 2019 Wiley Periodicals, Inc.

Assessment Of Changes In Regional Xenon-Ventilation, Perfusion, And Ventilation-Perfusion Mismatch Using Dual-Energy Computed Tomography After Pharmacological Treatment In Patients With Chronic Obstructive Pulmonary Disease: Visual And Quantitative Analysis.

Purpose: To assess changes in regional ventilation (V), perfusion (Q), and V-Q mismatch in patients with chronic obstructive pulmonary disease (COPD) after pharmacologic treatment using combined xenon-enhanced V and iodine-enhanced Q dual-energy CT (DECT). Patients and methods: Combined V and Q DECT were performed at baseline and after three-month pharmacologic treatment in 52 COPD patients. Anatomically co-registered virtual non-contrast images, V, Q, and V/Qratio maps were obtained. V/Q pattern was visually determined to be matched, mismatched, or reversed-mismatched and compared with the regional parenchymal disease patterns of each segment. DECT parameters for V, Q, and V-Q imbalance were quantified. Results: The parenchymal patterns on CT were not changed at follow-up. The segments with matched V/Q pattern were increased (80.2% to 83.6%) as the segments with reversed-mismatched V/Q pattern were decreased with improving ventilation (17.6% to 13.8%) after treatment. Changes of V/Q patterns were mostly observed in segments with bronchial wall thickening. Compared with patients without bronchial wall thickening, the quantified DECT parameters of V-Q imbalance were significantly improved in patients with bronchial wall thickening (p < 0.05). Changes in forced expiratory volume in one second after treatment were correlated with changes in the quantified DECT parameters (r = 0.327-0.342 or r = -0.406 and -0.303; p < 0.05). Conclusion: DECT analysis showed that the V-Q imbalance was improved after the pharmacological treatment in COPD patients, although the parenchymal disease patterns remained unchanged. This improvement of V-Q imbalance may occur mostly in the areas with bronchial wall thickening.

Clinical Utility of Quantitative CT Analysis for Fissure Completeness in Bronchoscopic Lung Volume Reduction: Comparison between CT and Chartis™.

OBJECTIVE: The absence of collateral ventilation (CV) is crucial for effective bronchoscopic lung volume reduction (BLVR) with an endobronchial valve. Here, we assessed whether CT can predict the Chartis™ results. MATERIALS AND METHODS: This study included 69 patients (mean age: 70.9 ± 6.6 years; 66 [95.7%] males) who had undergone CT to assess BLVR eligibility. The Chartis™ system (Pulmonox Inc.) was used to check CV. Experienced thoracic radiologists independently determined the completeness of fissures on volumetric CT images. RESULTS: The comparison between the visual and quantitative analyses revealed that 5% defect criterion showed good agreement. The Chartis™ assessment was performed for 129 lobes; 11 (19.6%) of 56 lobes with complete fissures on CT showed positive CV, while this rate was significantly higher (40 of 49 lobes, i.e., 81.6%) for lobes with incomplete fissures. The size of the fissure defect did not affect the rate of CV. Of the patients who underwent BLVR, 22 of 24 patients (91.7%) with complete fissures and three of four patients with incomplete fissures (75%) achieved target lobe volume reduction (TLVR). CONCLUSION: The quantitative analysis of fissure shows that incomplete fissures increased the probability of CV on Chartis™, while the defect size did not affect the overall rates. TLVR could be achieved even in some patients with relatively large fissure defect, if they showed negative CV on Chartis™.

Prediction of Pulmonary Function in Patients with Chronic Obstructive Pulmonary Disease: Correlation with Quantitative CT Parameters.

OBJECTIVE: We aimed to evaluate correlations between computed tomography (CT) parameters and pulmonary function test (PFT) parameters according to disease severity in patients with chronic obstructive pulmonary disease (COPD), and to determine whether CT parameters can be used to predict PFT indices. MATERIALS AND METHODS: A total of 370 patients with COPD were grouped based on disease severity according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) I-IV criteria. Emphysema index (EI), air-trapping index, and airway parameters such as the square root of wall area of a hypothetical airway with an internal perimeter of 10 mm (Pi10) were measured using automatic segmentation software. Clinical characteristics including PFT results and quantitative CT parameters according to GOLD criteria were compared using ANOVA. The correlations between CT parameters and PFT indices, including the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and FEV1, were assessed. To evaluate whether CT parameters can be used to predict PFT indices, multiple linear regression analyses were performed for all patients, Group 1 (GOLD I and II), and Group 2 (GOLD III and IV). RESULTS: Pulmonary function deteriorated with increase in disease severity according to the GOLD criteria (p < 0.001). Parenchymal attenuation parameters were significantly worse in patients with higher GOLD stages (p < 0.001), and Pi10 was highest for patients with GOLD III (4.41 ± 0.94 mm). Airway parameters were nonlinearly correlated with PFT results, and Pi10 demonstrated mild correlation with FEV1/FVC in patients with GOLD II and III (r = 0.16, p = 0.06 and r = 0.21, p = 0.04, respectively). Parenchymal attenuation parameters, airway parameters, EI, and Pi10 were identified as predictors of FEV1/FVC for the entire study sample and for Group 1 (R² = 0.38 and 0.22, respectively; p < 0.001). However, only parenchymal attenuation parameter, EI, was identified as a predictor of FEV1/FVC for Group 2 (R² = 0.37, p < 0.001). Similar results were obtained for FEV1. CONCLUSION: Airway and parenchymal attenuation parameters are independent predictors of pulmonary function in patients with mild COPD, whereas parenchymal attenuation parameters are dominant independent predictors of pulmonary function in patients with severe COPD.

The effect of a multidisciplinary team on the implementation rates of major diagnostic and therapeutic procedures of chronic thromboembolic pulmonary hypertension.

BACKGROUND: Although guidelines have recommended that patients with chronic thromboembolic pulmonary hypertension (CTEPH) should be managed by a multidisciplinary team (MDT), there is a lack of clinical data indicating that the MDT improves CTEPH management. OBJECTIVES: The study aimed to identify the effect of an MDT on CTEPH management. METHODS: We divided the study period into pre-MDT and post-MDT eras and compared the implementation rates of major diagnostic and therapeutic procedures. RESULTS: Of 116 patients with CTEPH, 42 (36.2%) were diagnosed in the post-MDT era. The implementation rates of right heart catheterization (10.8% vs. 97.6%, p < 0.001) and pulmonary endarterectomy (32.4% vs. 59.5%, p < 0.005) were significantly increased in the post-MDT era. Balloon pulmonary angioplasty was not performed in the pre-MDT era but was performed in the post-MDT era. CONCLUSIONS: The MDT appears to be associated with improved CTEPH management.

Cardiac computed tomography for the localization of mitral valve prolapse: scallop-by-scallop comparisons with echocardiography and intraoperative findings.

AIMS: We compared the diagnostic accuracy of cardiac computed tomography (CT) with that of echocardiography for the detection of mitral valve prolapse (MVP) on a scallop-by-scallop basis, using surgical inspection as a reference standard. METHODS AND RESULTS: This retrospective study included 145 patients (mean age 53 years; 94 men) who underwent surgical MVP repair or replacement and preoperative cardiac CT between May 2011 and October 2013. The prolapsed scallop was localized using cardiac CT and echocardiography according to the Carpentier method (anterior leaflet: from lateral to medial A1, A2, A3; posterior leaflet: P1, P2, P3). The per-scallop sensitivity and specificity of each method were compared, using surgical inspection as a reference standard. Interobserver agreement for the CT analysis was tested between three independent readers. Surgically, MVP was confirmed in 26% (226/870) scallops, with 56% (81/145) of the patients showing a single-scallop prolapse. The per-scallop sensitivity of cardiac CT was lower than that of echocardiography (80% vs. 87%, P = 0.004), with similar specificity (both 95%). For single-scallop lesions, cardiac CT showed good sensitivity (94%) and specificity (95%), with no significant difference to echocardiography. For the 64 patients with multiple scallop prolapse, CT underestimated the extent of MVP in 31 (49%) patients and echocardiography in 22 (34%) patients. Interobserver agreement was good, with kappa = 0.72-0.74. CONCLUSION: Cardiac CT provides a feasible method for localizing MVP on a per-scallop basis, but it may underestimate the extent of prolapsed scallop compared with echocardiography, particularly in patients with multiple-scallop lesions.

Human Metapneumovirus Infection: Pneumonia Risk Factors in Patients With Solid Organ Transplantation and Computed Tomography Findings.

BACKGROUND: Human metapneumovirus (HMPV) is a newly detected pathogen that can cause lower respiratory tract disease. Clinical characteristics, computed tomography (CT) findings, and outcomes of HMPV pneumonia in patients with solid organ transplantation (SOT) have not been well demonstrated. METHODS: Between January 2010 and February 2016, clinical and imaging findings of 59 patients with SOT (types of organ: kidney, 37; liver, 16; heart, 4; and pancreas and kidney, 2) who had HMPV infection detected in nasopharyngeal or bronchoalveolar lavage by reverse transcription polymerase chain reaction were retrospectively evaluated. RESULTS: Most (90%) of the patients were detected between March and June. In the 59 patients with SOT with upper respiratory tract infection (URI), 29 (49%) progressed to lower respiratory tract disease after a median of 7 days (range, 2-31 days). Coinfection was noted in 39% of the patients. In Cox proportional hazards analysis, low lymphocyte count (≤0.7 × 10/µL; hazard ratio, 2.24; 95% confidence interval, 1.04-4.85; P = 0.04) and high C-reactive protein (>10 mg/dL; hazard ratio, 2.93; 95% confidence interval, 1.19-7.21; P = 0.02) at URI diagnosis were associated with HMPV pneumonia. On CT, HMPV pneumonia presented as bilateral ill-defined centrilobular nodules, consolidation and ground-glass opacities, whereas lymphadenopathy or effusion is not common. There were no significantly different imaging CT findings between patients with HMPV infection alone and those with coinfection. CONCLUSIONS: Human metapneumovirus pneumonias were detected in nearly half of patients with SOT showing URI symptoms with positive HMPV, and low lymphocyte count and high C-reactive protein at URI diagnosis were significant factors associated with HMPV pneumonia.

Prediction of survival by texture-based automated quantitative assessment of regional disease patterns on CT in idiopathic pulmonary fibrosis.

OBJECTIVES: To retrospectively investigate whether the baseline extent and 1-year change in regional disease patterns on CT can predict survival of patients with idiopathic pulmonary fibrosis (IPF). METHODS: A total of 144 IPF patients with CT scans at the time of diagnosis and 1 year later were included. The extents of five regional disease patterns were quantified using an in-house texture-based automated system. The fibrosis score was defined as the sum of the extent of honeycombing and reticular opacity. The Cox proportional hazard model was used to determine the independent predictors of survival. RESULTS: A total of 106 patients (73.6%) died during the follow-up period. Univariate analysis revealed that age, baseline forced vital capacity, total lung capacity, diffusing capacity of the lung for carbon monoxide, six-minute walk distance, desaturation, honeycombing, reticular opacity, fibrosis score, and interval changes in honeycombing and fibrosis score were significantly associated with survival. Multivariate analysis revealed that age, desaturation, fibrosis score and interval change in fibrosis score were significant independent predictors of survival (p = 0.003, <0.001, 0.001 and <0.001). The C-index for the developed model was 0.768. CONCLUSION: Texture-based, automated CT quantification of fibrosis can be used as an independent predictor of survival in IPF patients. KEY POINTS: • Automated quantified fibrosis on CT was a significant predictor of survival. • Automated quantified interval change in fibrosis on CT was an independent predictor. • The predictive model showed comparable discriminative power with a C-index of 0.768. • Automated CT quantification can be considered to evaluate prognosis in routine practice.

Size variation and collapse of emphysema holes at inspiration and expiration CT scan: evaluation with modified length scale method and image co-registration.

A novel approach of size-based emphysema clustering has been developed, and the size variation and collapse of holes in emphysema clusters are evaluated at inspiratory and expiratory computed tomography (CT). Thirty patients were visually evaluated for the size-based emphysema clustering technique and a total of 72 patients were evaluated for analyzing collapse of the emphysema hole in this study. A new approach for the size differentiation of emphysema holes was developed using the length scale, Gaussian low-pass filtering, and iteration approach. Then, the volumetric CT results of the emphysema patients were analyzed using the new method, and deformable registration was carried out between inspiratory and expiratory CT. Blind visual evaluations of EI by two readers had significant correlations with the classification using the size-based emphysema clustering method (r-values of reader 1: 0.186, 0.890, 0.915, and 0.941; reader 2: 0.540, 0.667, 0.919, and 0.942). The results of collapse of emphysema holes using deformable registration were compared with the pulmonary function test (PFT) parameters using the Pearson's correlation test. The mean extents of low-attenuation area (LAA), E1 (<1.5 mm), E2 (<7 mm), E3 (<15 mm), and E4 (≥15 mm) were 25.9%, 3.0%, 11.4%, 7.6%, and 3.9%, respectively, at the inspiratory CT, and 15.3%, 1.4%, 6.9%, 4.3%, and 2.6%, respectively at the expiratory CT. The extents of LAA, E2, E3, and E4 were found to be significantly correlated with the PFT parameters (r=-0.53, -0.43, -0.48, and -0.25), with forced expiratory volume in 1 second (FEV1; -0.81, -0.62, -0.75, and -0.40), and with diffusing capacity of the lungs for carbon monoxide (cDLco), respectively. The fraction of emphysema that shifted to the smaller subgroup showed a significant correlation with FEV1, cDLco, forced expiratory flow at 25%-75% of forced vital capacity, and residual volume (RV)/total lung capacity (r=0.56, 0.73, 0.40, and -0.58). A detailed assessment of the size variation and collapse of emphysema holes may be useful for understanding the dynamic collapse of emphysema and its functional relation.

Improvement in Ventilation-Perfusion Mismatch after Bronchoscopic Lung Volume Reduction: Quantitative Image Analysis.

Purpose To evaluate whether bronchoscopic lung volume reduction (BLVR) increases ventilation and therefore improves ventilation-perfusion (V/Q) mismatch. Materials and Methods All patients provided written informed consent to be included in this study, which was approved by the Institutional Review Board (2013-0368) of Asan Medical Center. The physiologic changes that occurred after BLVR were measured by using xenon-enhanced ventilation and iodine-enhanced perfusion dual-energy computed tomography (CT). Patients with severe emphysema plus hyperinflation who did not respond to usual treatments were eligible. Pulmonary function tests, the 6-minute walking distance (6MWD) test, quality of life assessment, and dual-energy CT were performed at baseline and 3 months after BLVR. The effect of BLVR was assessed with repeated-measures analysis of variance. Results Twenty-one patients were enrolled in this study (median age, 68 years; mean forced expiratory volume in 1 second [FEV1], 0.75 L ± 0.29). After BLVR, FEV1 (P < .001) and 6MWD (P = .002) improved significantly. Despite the reduction in lung volume (-0.39 L ± 0.44), both ventilation per voxel (P < .001) and total ventilation (P = .01) improved after BLVR. However, neither perfusion per voxel (P = .16) nor total perfusion changed significantly (P = .49). Patients with lung volume reduction of 50% or greater had significantly better improvement in FEV1 (P = .02) and ventilation per voxel (P = .03) than patients with lung volume reduction of less than 50%. V/Q mismatch also improved after BLVR (P = .005), mainly owing to the improvement in ventilation. Conclusion The dual-energy CT analyses showed that BLVR improved ventilation and V/Q mismatch. This increased lung efficiency may be the primary mechanism of improvement after BLVR, despite the reduction in lung volume. © RSNA, 2017 Online supplemental material is available for this article.

Comparison of chest CT findings in nontuberculous mycobacterial diseases vs. Mycobacterium tuberculosis lung disease in HIV-negative patients with cavities.

OBJECTIVES: This article focuses on the differences between CT findings of HIV-negative patients who have cavities with nontuberculous mycobacteria (NTM) disease and those with Mycobacterium tuberculosis infections (TB). METHODS: We retrospectively reviewed 128 NTM disease patients (79 males and 49 females) with cavities in chest CT, matched for age and gender with 128 TB patients in the same period. Sputum cultures of all patients were positive for pathogens. Two independent chest radiologists evaluated the characteristics of the largest cavity and related factors. RESULTS: Interobserver agreement was excellent (κ value, 0.853-0.938). Cavity walls in NTM disease were significantly thinner (6.9±4 mm vs 10.9±6 mm, P<0.001) and more even (the ratio of thickness, 2.6±1 vs 3.7±2, P<0.001) than those in TB. The thickening of adjacent pleura next to the cavity was also significantly thicker in NTM than TB (P<0.001). However, in the multivariate analysis, thickening of adjacent pleura was the only significant factor among the representative cavity findings (Odds ratio [OR], 6.49; P<0.001). In addition, ill-defined tree-in-bud nodules (OR, 8.82; P<0.001), number of non-cavitary nodules (≥10mm) (OR, 0.72; P = 0.003), and bronchiectasis in the RUL (OR, 5.3; P = 0.002) were significantly associated ancillary findings with NTM disease in the multivariate analysis. CONCLUSIONS: The major cavities in NTM disease generally have thinner and more even walls than those in TB. When cavities are associated with adjacent pleural thickening, ill-defined satellite tree-in-bud nodules, or fewer non-cavitary nodules ≥10 mm, these CT findings are highly suggestive of NTM disease rather than TB.