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.

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.

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.

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.

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.

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.

Assessment of regional emphysema, air-trapping and Xenon-ventilation using dual-energy computed tomography in chronic obstructive pulmonary disease patients.

OBJECTIVES: To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO) expiration CTs. METHODS: 52 prospectively enrolled COPD patients underwent xenon ventilation dual-energy CT during WI and WO periods and pulmonary function tests (PFTs). The parenchymal attenuation parameters (emphysema index (EI), gas-trapping index (GTI) and air-trapping index (ATI)) and xenon ventilation parameters (xenon in WI (Xe-WI), xenon in WO (Xe-WO) and xenon dynamic (Xe-Dyna)) of whole lung and three divided areas (emphysema, hyperinflation and normal) were calculated on virtual non-contrast images and ventilation images. Pearson correlation, linear regression analysis and one-way ANOVA were performed. RESULTS: EI, GTI and ATI showed a significant correlation with Xe-WI, Xe-WO and Xe-Dyna (EI R = -.744, -.562, -.737; GTI R = -.621, -.442, -.629; ATI R = -.600, -.421, -.610, respectively, p < 0.01). All CT parameters showed significant correlation with PFTs except forced vital capacity (FVC). There was a significant difference in GTI, ATI and Xe-Dyna in each lung area (p < 0.01). CONCLUSIONS: The parenchymal attenuation change between inspiration/expiration CTs and xenon dynamic change between xenon WI- and WO-CTs correlate significantly. There are alterations in the dynamics of xenon ventilation between areas of emphysema. KEY POINTS: • The xenon ventilation change correlates with the parenchymal attenuation change. • The xenon ventilation change shows the difference between three lung areas. • The combination of attenuation and xenon can predict more accurate PFTs.

Optimal threshold of subtraction method for quantification of air-trapping on coregistered CT in COPD patients.

OBJECTIVES: To investigate the optimal threshold of subtraction method for quantification of air trapping on co-registered CT in COPD patients in correlation with pulmonary function parameters. METHODS: From June 2005 to October 2010, 174 patients were included in our study. Inspiration and expiration CT were performed followed by non-rigid registration using in-house software. The subtraction value per voxel between inspiration and registered expiration CT was obtained, and volume fraction of air trapping (air trapping index, ATI), using variable thresholds was calculated. ATI, expiration/inspiration ratio of mean lung density (E/I MLD) and the percentage of lung voxels below -856 HU on expiration CT (Exp-856) were correlated with FEF25-75% and RV/TLC. RESULTS: The highest correlation coefficient with FEF25-75% was -0.656, using the threshold of 80 HU. As for RV/TLC, the highest correlation coefficient was 0.664, using the threshold of 30 HU. When plotting the relationship between subtraction thresholds and FEF25-75% and RV/TLC, the threshold of 60 HU was most suitable (r = -0.649 and 0.651). Those correlation coefficients were comparable to the results with E/I MLD (r = -0.670 and 0.657) and Exp-856 (r = -0.604 and 0.565). CONCLUSIONS: The optimal threshold for quantification of air trapping was 60 HU and showed comparable correlations with pulmonary function parameters. KEY POINTS: • The optimal CT threshold of subtraction method for air trapping was 60 HU. • ATI with 60 HU threshold was comparable to E/I MLD and Exp -856 . • Emphysema may substantially contribute to air trapping with statistical significance (P < 0.001).

Texture-Based Automated Quantitative Assessment of Regional Patterns on Initial CT in Patients With Idiopathic Pulmonary Fibrosis: Relationship to Decline in Forced Vital Capacity.

OBJECTIVE: The aim of our study was to retrospectively determine predictive factors for a decline in forced vital capacity (FVC) on initial CT using texture-based automated quantification in patients with idiopathic pulmonary fibrosis (IPF). MATERIALS AND METHODS: For our study, 193 patients with IPF and 1-year follow-up pulmonary function tests were enrolled in our study. A texture-based automated system used in-house software to quantify six regional CT patterns: normal, ground-glass opacity (GGO), reticular opacity (RO), honeycombing, emphysema, and consolidation. A decline of FVC was defined as a decrease in the initial FVC of more than 10%. RESULTS: A decline of FVC occurred in 32 patients: The mean volume of the decline in FVC was 0.43 ± 0.18 (SD) L. The mean extents of GGO, RO, honeycombing, emphysema, and consolidation in all 193 patients were as follows: 12.3% ± 11.9%, 16.8% ± 9.8%, 7.1% ± 6.7%, 3.9% ± 5.5%, and 2.8% ± 0.8%, respectively. A multivariate analysis revealed that RO was the sole independent predictor for a decline in FVC (p = 0.012; adjusted odds ratio, 1.047). ROC analysis showed that the AUC of RO was 0.641 and that the optimal RO cutoff value was 22.05% (sensitivity, 50.0%; specificity, 81.4%; negative predictive value, 89.1%). CONCLUSION: RO of less than 22.05% in extent can accurately predict stable IPF at 1-year follow-up in terms of FVC.

Detailed analysis of the density change on chest CT of COPD using non-rigid registration of inspiration/expiration CT scans.

OBJECTIVES: One objective was to evaluate the air trapping index (ATI), measured by inspiration/expiration CT, in COPD patients and nonsmokers. Another objective was to assess the association between the pulmonary function test (PFT) and CT parameters such as ATI or other indices, separately in the whole lung, in emphysema, and in hyperinflated and normal lung areas. METHODS: One hundred and thirty-eight COPD patients and 29 nonsmokers were included in our study. The ATI, the emphysema index (EI), the gas trapping index (Exp -856) and expiration/inspiration ratio of mean lung density (E/Iratio of MLD) were measured on CT. The values of the whole lung, of emphysema, and of hyperinflated and normal lung areas were compared and then correlated with various PFT parameters. RESULTS: Compared with nonsmokers, COPD patients showed a higher ATI in the whole lung and in each lung lesion (all P < 0.05). The ATI showed a higher correlation than EI with FEF25-75%, RV and RV/TLC, and was comparable to Exp -856 and the E/I ratio of MLD. The ATI of emphysema and hyperinflated areas on CT showed better correlation than the normal lung area with PFT parameters. CONCLUSIONS: Detailed analysis of density change at inspiration and expiration CT of COPD can provide new insights into pulmonary functional impairment in each lung area. KEY POINTS: • COPD patients show significant air trapping in the lung. • The air trapping index is a comparable parameter to other CT indices. • Air trapping of emphysema and hyperinflated lung areas relates to functional loss. • The emphysema area changes more, with less air trapping than other areas.

Evolving Early Lung Cancers Detected During Follow-Up of Idiopathic Interstitial Pneumonia: Serial CT Features.

OBJECTIVE: The purpose of this study was to evaluate the CT characteristics of newly developed lung cancer on CT studies obtained during follow-up of idiopathic interstitial pneumonia (IIP) before the appearance of identifiable tumors to the time of detectable lung cancer and thereafter. MATERIALS AND METHODS: The study sample included 66 cancers diagnosed in 63 patients with IIP and lung cancer (59 men, four women; median age, 64 years; range, 40-85 years) between October 1998 and July 2012. Two radiologists independently reviewed 193 CT scans, determined the earliest presence of cancer and IIP, and evaluated tumor size, lobar and axial location, shape, and tumor density. Delay in clinical diagnosis and doubling time were measured with first and second follow-up CT examinations. RESULTS: Interobserver agreement was good (κ > 0.77). The median tumor size was 17 mm (range, 5-30 mm) for the 46 T1a and 20 T1b cancers. Most of the tumors (42 [63.6%]) were located in the lower lobes. Thirty-five tumors (53.0%) were at the interface between fibrotic cyst and normal lung, and 21 (31.8%) were in the midst of fibrotic lung cysts. Most of the tumors had a round or oval shape (52 [78.8%]) and were solid (62 [93.9%]). The median delay in diagnosis was 46 days (range, 8-760 days). The first median doubling time was 77 days (range, 15-525 days), and the second was 53 days (27-248). CONCLUSION: New lung cancers during CT follow-up of IIP usually appear as small solid nodules with a round or oval shape. Most cancers are located at the interface between fibrotic cyst and normal lung or in the midst of fibrotic cysts of the lower lobes of subpleural lung.

Comparison of a New Integral-Based Half-Band Method for CT Measurement of Peripheral Airways in COPD With a Conventional Full-Width Half-Maximum Method Using Both Phantom and Clinical CT Images.

OBJECTIVES: To compare a new integral-based half-band method (IBHB) and a conventional full-width half-maximum (FWHM) method in measuring peripheral airway dimensions at airway phantoms and thin-section computed tomography of chronic obstructive pulmonary disease (COPD). METHODS: The IBHB was validated and compared using airway phantoms and 50 patients with COPD. Airway parameters (wall area percentage [WA%], mean lumen radius, and mean wall thickness) were measured at fourth to sixth generations of the right apical bronchus. Matched results from 2 methods were compared and correlated with forced expiratory volume (FEV) in 1 second (FEV1), FEV1 / forced vital capacity (FVC), and global initiative for chronic obstructive lung disease (GOLD) stage. Linear regression analysis was performed using airway dimensions and emphysema index. RESULTS: The IBHB generated more accurate measurements at phantom study. Measured airway parameters by both methods at thin-section computed tomography study were significantly different (all P < 0.05, paired t test). The IBHB method-measured WA% and wall thickness were significantly smaller. Mean WA% with IBHB also showed better correlation than that with FWHM (FEV1, r = -0.52 vs -0.28; FEV1 / FVC, r = -0.41 vs r = -0.20; GOLD, 0.52 vs 0.33, respectively). Linear regression analysis revealed fifth-generation WA% measured by IBHB was an independent variable, and addition to emphysema index increased predictability (FEV1, r = 0.63; FEV1 / FVC, r = 0.61; GOLD, r = 0.70). CONCLUSIONS: The new IBHB measured peripheral airway dimensions differently than FWHM and showed better correlations with functional parameters in COPD.

Demonstration of mitral valve prolapse with CT for planning of mitral valve repair.

Mitral valve prolapse (MVP), the most frequent cause of severe nonischemic mitral regurgitation, often warrants surgical or interventional valve repair. The severity of mitral regurgitation positively correlates with the development of heart failure and death. Even in patients who are asymptomatic, severe mitral regurgitation causes higher rates of death, heart failure, and atrial fibrillation. Repair procedures for mitral regurgitation have progressed to include leaflet repair, chordal transfer, ring or band annuloplasty, and new percutaneous procedures. In planning for mitral valve repair, detection and localization of mitral valve abnormalities are important. The causes of mitral regurgitation include degenerative mitral valve (eg, prolapsed leaflet, myxomatous degeneration, and Barlow disease [excessive degenerated tissues with elongated chordae]). Cardiac computed tomography (CT) is helpful for depicting mitral valve abnormalities. It allows complete visualization of cardiac anatomic features, including the coronary arteries, paravalvular structures, and cardiac wall motion. This review addresses the role of cardiac CT in depicting anatomic features of the mitral valve, provides a practical method for localizing the exact site of MVP, and discusses the CT findings of various causes of mitral regurgitation. The first step in reconstructing CT images for MVP is to select the best cardiac phase for depicting the anatomic features of the mitral valve. Additional views of the mitral valve then show the specific mitral valve abnormality. This article provides technical tips for demonstrating MVP with CT, as well as imaging results for various causes of MVP and intraoperative findings. Online supplemental material is available for this article.

Optimal approach for diagnosing peripheral lung nodules by combining electromagnetic navigation bronchoscopy and radial probe endobronchial ultrasound.

INTRODUCTION: Electromagnetic navigation bronchoscopy (ENB) and radial probe endobronchial ultrasound (RP-EBUS) are essential bronchoscopic procedures for diagnosing peripheral lung lesions. Despite their individual advantages, the optimal circumstances for their combination remain uncertain. METHODS: This single-center retrospective study enrolled 473 patients with 529 pulmonary nodules who underwent ENB and/or RP-EBUS biopsies between December 2021 and December 2022. Diagnostic yield was calculated using strict, intermediate, and liberal definitions. In the strict definition, only malignant and specific benign lesions were deemed diagnostic at the time of the index procedure. The intermediate and liberal definitions included additional results from the follow-up period. RESULTS: The diagnostic yield of the strict definition was not statistically different among the three groups (ENB/Combination/RP-EBUS 63.8%/64.2%/62.6%, p = 0.944). However, the diagnostic yield was superior in the ENB + RP-EBUS group for nodules with a bronchus type II or III and a solid part <20 mm (odds ratio 1.96, 95% confidence interval 1.09-3.53, p = 0.02). In terms of complications, bleeding was significantly higher in the ENB + RP-EBUS group (ENB/Combination/RP-EBUS 3.7% /6.2/0.6%, p = 0.002), but no major adverse event was observed. CONCLUSION: The combination of ENB and RP-EBUS enhanced the diagnostic yield for nodules with bronchus type II or III and solid part <20 mm, despite a slightly elevated risk of bleeding. Careful patient selection based on nodule characteristics is important to benefit from this combined approach.

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.

Percutaneous CT-guided aspiration and core biopsy of pulmonary nodules smaller than 1 cm: analysis of outcomes of 305 procedures from a tertiary referral center.

OBJECTIVE: We conducted a retrospective analysis to evaluate the diagnostic outcomes of CT-guided aspiration and core biopsy of 305 pulmonary nodules measuring less than 1 cm. MATERIALS AND METHODS: We determined the diagnostic yield of using CT-guided aspiration and core biopsy to analyze 305 lesions in 290 patients. Diagnostic performance was evaluated according to the biopsy method, including aspiration alone, core biopsy alone, and combination use, and the consistency of the nodule, including solid, partly solid ground-glass opacity (GGO), and pure GGO. Final diagnoses were established in 268 of the 305 lesions (87.9%). Nondiagnostic biopsy results were obtained for 27 of the 268 lesions (10.1%). RESULTS: The overall sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of malignancy were 93.1% (148 of 159 lesions), 98.8% (81/82), 99.3% (148/149), and 88.0% (81/92), respectively; diagnostic accuracy was 95.0% (229/241). Using multivariate logistic regression analysis, we found that aspiration alone was a significant independent risk factor associated with diagnostic failure (odds ratio, 3.199; p = 0.001). CONCLUSION: The use of CT-guided aspiration and core biopsy resulted in a high diagnostic yield for pulmonary nodules smaller than 1 cm. The use of the aspiration method alone was an independent risk factor associated with diagnostic failure.

Low-dose chest computed tomography with sinogram-affirmed iterative reconstruction, iterative reconstruction in image space, and filtered back projection: studies on image quality.

OBJECTIVE: This study aimed to determine optimal strength of sinogram-affirmed iterative reconstruction (SAFIRE) and to evaluate image quality (IQ) of low-dose chest computed tomography (LDCT) using SAFIRE compared with iterative reconstruction in image space (IRIS) and filtered back projection (FBP). METHODS: Thirty patients underwent LDCT. Computed tomography (CT) was reconstructed using 5 strengths of SAFIRE (S1-S5), IRIS, and FBP. Objective noise of CT was measured. Two radiologists evaluated CT for subjective IQ, beam-hardening artifacts, and overall IQ. RESULTS: Measured noise was highest in FBP, followed by S1, S2, S3, IRIS, S4, and S5. S2 and S3 demonstrated significantly higher overall IQ scores than the other strengths (P < 0.05). Overall IQ and beam-hardening artifacts of S2 and S3 were significantly better than those in FBP and IRIS (P < 0.001). CONCLUSIONS: S2 or S3 strengths of SAFIRE can be used practically in clinical routines and may have more potential than IRIS and FBP for LDCT with improved IQ.

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.

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.

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.