RATIONALE:Validated thresholds for clinically meaningful change in quantitative CT (QCT) for fibrosis extent across algorithms remain unclear in idiopathic pulmonary fibrosis (IPF). OBJECTIVES:To evaluate minimal clinically important difference (MCID) for 1-year change in QCT metrics in IPF using different algorithms than previously reported, and to identify prognostically meaningful thresholds for effective risk stratification. METHODS:This multicenter retrospective study included IPF patients with baseline and 1-year follow-up CT. MCIDs for change in fibrosis score (ΔFS) derived from fully-automated CT quantification were estimated using an anchor-based approach with 1-year changes in forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLco), and a prognostic threshold was estimated using maximally selected log-rank statistics. Prognostic significance of ΔFS was evaluated in discovery and validation cohorts. RESULTS:The discovery cohort included 524 patients (mean age, 66.8 years; 79% men), and the external validation cohort included 224 patients (mean age, 69.6 years; 83% men). Anchor-based MCIDs were 2.72% for FVC and 4.52% for DLco, with a prognostic threshold of 4.05%. In the discovery cohort, 1-year ΔFS were independently associated with transplant-free survival (TFS), with greater risk when ΔFS exceeded MCID or prognostic thresholds (all, P < .001). In the validation cohort, ΔFS remained associated with TFS (adjusted HR, 1.11; 95%CI, 1.04-1.18), and all prespecified ΔFS thresholds were prognostic for overall TFS, with the prognostic threshold of ΔFS ≥ 4.05% showing the most consistent associations with both overall (adjusted HR, 2.78; 95%CI, 1.36-5.68) and 3-year TFS (adjusted HR, 2.88; 95%CI, 1.11-7.48). CONCLUSION:One-year change in FS and its thresholds were significantly associated with TFS, supporting annual CT follow-up with predefined QCT thresholds for monitoring and risk stratification in IPF.

To investigate whether a content-based image retrieval (CBIR) of similar chest CT images can help usual interstitial pneumonia (UIP) CT pattern classifications among readers with varying levels of experience. This retrospective study included patients who underwent high-resolution chest CT between 2013 and 2015 for the initial workup for fibrosing interstitial lung disease. UIP classifications were assigned to CT images by three thoracic radiologists, which served as the ground truth. One hundred patients were selected as queries. The CBIR retrieved the top three similar CT images with UIP classifications using a deep learning algorithm. The diagnostic accuracies and inter-reader agreement of nine readers before and after CBIR were evaluated. Of 587 patients (mean age, 63 years; 356 men), 100 query cases (26 UIP patterns, 26 probable UIP patterns, 5 indeterminate for UIP, and 43 alternative diagnoses) were selected. After CBIR, the mean accuracy (61.3

OBJECTIVE:This study aimed to evaluate changes in left ventricular and left atrial mechanics in relation to the severity of aortic stenosis (AS) by comparing computed tomography (CT)-derived strain values in patients with mild-to-severe AS. MATERIALS AND METHODS:This single-center retrospective study included 120 patients (median age, 76 years; 45.0% male), comprising 30, 30, and 60 patients with mild, moderate, and severe AS, respectively, all of whom underwent multiphase cardiac CT between 2015 and 2021. Patients were selected from 177 individuals who met the initial eligibility criteria, with matching for age, sex, and hypertension in a 1:1:2 ratio across the mild, moderate, and severe AS groups. Electrocardiography-gated cardiac CT images were analyzed to obtain various quantitative left ventricle (LV) and left atrium (LA) strain parameters. Statistical differences in cardiac CT-derived LV and LA strain parameters among mild, moderate, and severe AS were evaluated using the Kruskal-Wallis test, followed by post-hoc tests. RESULTS:The median LV global longitudinal strain differed significantly across AS severity (GLS: -19.4%, -18.2%, and -16.2% for mild, moderate, and severe AS, respectively; P < 0.001), with the absolute value decreasing as AS severity increased. Additionally, the median values of LV global circumferential strain (GCS: -29.8%, -30.8%, and -27.4%, respectively; P = 0.045), LV global radial strain (GRS: 50.1%, 50.3%, and 39.3%, respectively; P = 0.004), and LA conduit strain (11.5%, 11.2%, and 9.0%, respectively; P = 0.031) differed significantly according to AS severity, with lower absolute values observed in patients with severe AS. CONCLUSION:In patients with AS, CT-derived LV and LA strains revealed changes in myocardial deformation according to AS severity. Specifically, there was a gradual decrease in the absolute value of LV GLS with increasing AS severity and initial preservation until moderate AS, followed by an eventual decrease in the absolute values of LV GCS, LV GRS, and LA conduit strain in severe AS.

Chronic obstructive pulmonary disease (COPD) is a highly heterogeneous condition characterized by diverse pulmonary and extrapulmonary manifestations. Efforts to quantify its various components using CT imaging have advanced, aiming for more precise, objective, and reproducible assessment and management. Beyond emphysema and small airway disease, the two major components of COPD, CT quantification enables the evaluation of pulmonary vascular alteration, ventilation-perfusion mismatches, fissure completeness, and extrapulmonary features such as altered body composition, osteoporosis, and atherosclerosis. Recent advancements, including the application of deep learning techniques, have facilitated fully automated segmentation and quantification of CT parameters, while innovations such as image standardization hold promise for enhancing clinical applicability. Numerous studies have reported associations between quantitative CT parameters and clinical or physiologic outcomes in patients with COPD. However, barriers remain to the routine implementation of these technologies in clinical practice. This review highlights recent research on COPD quantification, explores advances in technology, and also discusses current challenges and potential solutions for improving quantification methods.

BACKGROUND:Although quantitative CT imaging offers objective evaluation of radiologic progression in non-idiopathic pulmonary fibrosis (IPF) fibrosing interstitial lung disease (ILD), clinically meaningful thresholds for defining progressive pulmonary fibrosis (PPF) remain unclear. RESEARCH QUESTION:What are the minimal clinically important differences (MCIDs) in quantitative CT imaging-based fibrosis score (FS) changes over 1 year and 6 months, and do these thresholds predict outcomes and enhance risk stratification in defining PPF among patients with non-IPF fibrosing ILD? STUDY DESIGN AND METHODS:This retrospective study included patients with non-IPF fibrosing ILD who underwent volumetric CT imaging at baseline and the 1-year follow-up. FS was calculated using a deep learning-based quantitative CT imaging algorithm. The MCID for FS change was determined using anchor-based methods, referencing absolute 1-year FVC change. The association of FS change MCID with transplant-free survival (TFS) and its alignment with PPF criteria were analyzed using Cox regression. Concordance between quantitative CT imaging-based and visual assessments was also assessed. RESULTS:Among 476 patients, the 1-year and 6-month MCIDs were 2.24% and 1.34%, respectively. Exceeding the 1-year MCID was independently associated with poorer TFS (adjusted hazard ratio [HR], 3.01; 95% CI, 2.19-4.14). Quantitative CT imaging-based progression provided additional risk stratification in patients with discordant PPF criteria, including those with disagreement on visual progression (P = .02). Patients with both visual and quantitative CT imaging-based progression showed worse outcomes than those with visual progression alone (P < .001). FS changes of more than the 6-month MCID were also associated with worse outcome (adjusted HR, 2.82; 95% CI, 1.57-5.04). INTERPRETATION:Quantitative CT imaging-based PPF definition using 1-year change in FS was prognostic across patients with non-IPF fibrosing ILDs and enhanced risk stratification in patients with discordant PPF assessments.

Prognosis of non–small cell lung cancer with pathologic separate nodules (SNs) in the same lobe varied according to the presence of ground-glass opacity; prognosis was better only for subsolid SNs compared with other T3 descriptors.

OBJECTIVES:To identify risk factors in patients with surgically-resected pathological stage I non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations dichotomized according to the presence of ground-glass opacity (GGO). METHODS:Patients with pathological stage I NSCLC harbouring EGFR mutations who underwent curative resection between 2010 and 2020 were retrospectively included. Cox regression was used to investigate risk factors for overall survival (OS). RESULTS:Out of 461 patients (mean age, 61.7 ± 9.9 years; 306 women), 165 had solid tumours and 296 had subsolid tumours. In solid tumours, visceral pleural invasion (VPI) and a central location were independent risk factors for shorter OS (hazard ratio [HR], 1.95 [95% CI: 1.09, 3.49]; P = .02 and HR, 2.62 [95% CI: 1.46, 4.73]; P = .001, respectively). In subsolid tumours, older age and VPI were independent risk factors for shorter OS (HR, 1.05 [95% CI: 1.02, 1.09]; P = .002 and HR, 2.74 [95% CI: 1.52, 4.95]; P = .001, respectively). Patients with VPI(+) or central solid lung cancers exhibited the worst prognoses, whereas those with VPI(+) subsolid lung cancers exhibited comparable prognoses to those with VPI(-) or peripheral solid lung cancers. CONCLUSION:In EGFR-mutated pathological stage I NSCLC, VPI was a common risk factor for shorter OS in patients with both subsolid and solid lung cancers. Patients with solid lung cancer with VPI or a central location had the worst prognoses. ADVANCES IN KNOWLEDGE:Adjuvant EGFR-tyrosine kinase inhibitor may be beneficial for those with solid lung cancer with visceral pleural invasion or a central location.

In patients with idiopathic pulmonary fibrosis–pathologic usual interstitial pneumonia (UIP), certain autoimmune features were indeterminate for UIP or associated with alternative CT patterns and higher overall survival.

Background Application of multimodal large language models (LLMs) with both textual and visual capabilities has been steadily increasing, but their ability to interpret radiologic images is still doubted. Purpose To evaluate the accuracy of LLMs and compare it with that of human readers with varying levels of experience and to assess the factors affecting LLM accuracy in answering New England Journal of Medicine Image Challenge cases. Materials and Methods Radiologic images of cases from October 13, 2005, to April 18, 2024, were retrospectively reviewed. Using text and image inputs, LLMs (Open AI's GPT-4 Turbo with Vision [GPT-4V] and GPT-4 Omni [GPT-4o], Google's DeepMind Gemini 1.5 Pro, and Anthropic's Claude 3) provided answers. Human readers (seven junior faculty radiologists, two clinicians, one in-training radiologist, and one medical student), blinded to the published answers, also answered. LLM accuracy with and without image inputs and short (cases from 2005 to 2015) versus long text inputs (from 2016 to 2024) was evaluated in subgroup analysis to determine the effect of these factors. Factor analysis was assessed using multivariable logistic regression. Accuracy was compared with generalized estimating equations, with multiple comparisons adjusted by using Bonferroni correction. Results A total of 272 cases were included. GPT-4o achieved the highest overall accuracy among LLMs (59.6%; 162 of 272), outperforming a medical student (47.1%; 128 of 272; P < .001) but not junior faculty (80.9%; 220 of 272; P < .001) or the in-training radiologist (70.2%; 191 of 272; P = .003). GPT-4o exhibited similar accuracy regardless of image inputs (without images vs with images, 54.0% [147 of 272] vs 59.6% [162 of 272], respectively; P = .59). Human reader accuracy was unaffected by text length, whereas LLMs demonstrated higher accuracy with long text inputs (all P < .001). Text input length affected LLM accuracy (odds ratio range, 3.2 [95% CI: 1.9, 5.5] to 6.6 [95% CI: 3.7, 12.0]). Conclusion LLMs demonstrated substantial accuracy with text and image inputs, outperforming a medical student. However, their accuracy decreased with shorter text lengths, regardless of image input. © RSNA, 2024 Supplemental material is available for this article.

BACKGROUND:The diagnosis of distant metastasis on preoperative examinations for non-small cell lung cancer (NSCLC) can be challenging, leading to surgery for some patients with uncertain metastasis. This study evaluated the prognostic impact of delayed diagnosis of metastasis on patients who underwent upfront surgery.METHODS:The study enrolled patients who underwent lobectomy or pneumonectomy for NSCLC between June 2010 and December 2017 and evaluated the presence of distant metastasis before surgery. Overall survival (OS) for patients with stage IV cancer was compared with that for patients without metastasis, and the prognostic factors were analyzed.RESULTS:Of 3046 patients (mean age, 63 years; 1770 men), 100 (3.3 %) had distant metastasis, diagnosed preoperatively in 1.4 % (42/3046) and postoperatively in 1.9 % (58/3046) of the patients. The two most common metastasis sites diagnosed after surgery were contralateral lung (22/58, 37.9 %) and ipsilateral pleura (16/58, 27.6 %). The OS (median, 42.7 months) for the patients with stage IV cancer diagnosed postoperatively was comparable with that for the patients with stage IIIB cancer (P = 0.865), whereas the OS (median OS, 91.7 months) for the patients with stage IV cancer diagnosed preoperatively was better than for the patients with stage IIIB cancer (P = 0.001). Among the patients with distant metastasis, squamous cell type (hazard ratio [HR], 3.15; P = 0.002) and systemic treatment for metastasis (HR, 2.42; P = 0.002) were independent predictors of worse OS.CONCLUSIONS:Among NSCLC patients undergoing upfront surgery, the OS for the patients with stage IV cancer diagnosed postoperatively was comparable with that for the patients with stage IIIB cancer. For patients with stage IV disease, squamous cell type and systemic treatment for metastasis were prognostic factors for poorer OS.

There is still a debate regarding the prognostic implication of lymphovascular invasion (LVI) in stage I lung adenocarcinoma. Ground-glass opacity (GGO) on CT is known to correlate with a less invasive or lepidic component in adenocarcinoma, which may influence the strength of prognostic factors. This study aimed to explore the prognostic value of LVI in stage I lung adenocarcinoma based on the presence of GGO. Stage I lung adenocarcinoma patients receiving lobectomy between 2010 and 2019 were retrospectively categorized as GGO-positive or GGO-negative (solid adenocarcinoma) on CT. Multivariable Cox regression analyses were performed for disease-free survival (DFS) and overall survival (OS) to evaluate the prognostic significance of pathologic LVI based on the presence of GGO. Of 924 patients included (mean age, 62.5 ± 9.2 years; 505 women), 525 (56.8

OBJECTIVE:To validate selection criteria for sublobar resection in patients with lung cancer with respect to recurrence, and to investigate predictors for recurrence in patients for whom the criteria are not suitable. METHODS:Patients who underwent sublobar resection for lung cancer between July 2010 and December 2018 were retrospectively included. The criteria for curative sublobar resection were consolidation-to-tumor ratio ≤0.50 and size ≤3.0 cm in tumors with a ground-glass opacity (GGO) component (GGO group), and size of ≤2.0 cm and volume doubling time ≥400 days in solid tumors (solid group). Cox regression was used to identify predictors for time-to-recurrence (TTR) in tumors outside of these criteria (non-curative group). RESULTS:Out of 530 patients, 353 were classified into the GGO group and 177 into the solid group. In the GGO group, the 2-year recurrence rates in curative and non-curative groups were 2.1 and 7.7%, respectively (p = 0.054). In the solid group, the 2-year recurrence rates in curative and non-curative groups were 0.0 and 28.6%, respectively (p = 0.03). Predictors of 2-year TTR after non-curative sublobar resection were pathological nodal metastasis (hazard ratio [HR], 6.63; p = 0.02) and lymphovascular invasion (LVI; HR, 3.28; p = 0.03) in the GGO group, and LVI (HR, 4.37; p < 0.001) and fibrosis (HR, 3.18; p = 0.006) in the solid group. CONCLUSION:The current patient selection criteria for sublobar resection are satisfactory. LVI was a predictor for recurrence after non-curative resection. ADVANCES IN KNOWLEDGE:This result supports selection criteria of patients for sublobar resection. LVI may help predict recurrence after non-curative sublobar resection.

Rationale: The optimal follow-up computed tomography (CT) interval for detecting the progression of interstitial lung abnormality (ILA) is unknown. Objectives: To identify optimal follow-up strategies and extent thresholds on CT relevant to outcomes. Methods: This retrospective study included self-referred screening participants aged 50 years or older, including nonsmokers, who had imaging findings relevant to ILA on chest CT scans. Consecutive CT scans were evaluated to determine the dates of the initial CT showing ILA and the CT showing progression. Deep learning-based ILA quantification was performed. Cox regression was used to identify risk factors for the time to ILA progression and progression to usual interstitial pneumonia (UIP). Measurements and Main Results: Of the 305 participants with a median follow-up duration of 11.3 years (interquartile range, 8.4-14.3 yr), 239 (78.4%) had ILA on at least one CT scan. In participants with serial follow-up CT studies, ILA progression was observed in 80.5% (161 of 200), and progression to UIP was observed in 17.3% (31 of 179), with median times to progression of 3.2 years (95% confidence interval [CI], 3.0-3.4 yr) and 11.8 years (95% CI, 10.8-13.0 yr), respectively. The extent of fibrosis on CT was an independent risk factor for ILA progression (hazard ratio, 1.12 [95% CI, 1.02-1.23]) and progression to UIP (hazard ratio, 1.39 [95% CI, 1.07-1.80]). Risk groups based on honeycombing and extent of fibrosis (1% in the whole lung or 5% per lung zone) showed significant differences in 10-year overall survival (P = 0.02). Conclusions: For individuals with initially detected ILA, follow-up CT at 3-year intervals may be appropriate to monitor radiologic progression; however, those at high risk of adverse outcomes on the basis of the quantified extent of fibrotic ILA and the presence of honeycombing may benefit from shortening the interval for follow-up scans.

Background Although lung adenocarcinoma with ground-glass opacity (GGO) is known to have distinct characteristics, limited data exist on whether the recurrence pattern and outcomes in patients with resected lung adenocarcinoma differ according to GGO presence at CT. Purpose To examine recurrence patterns and associations with outcomes in patients with resected lung adenocarcinoma according to GGO at CT. Materials and Methods Patients who underwent CT followed by lobectomy or pneumonectomy for lung adenocarcinoma between July 2010 and December 2017 were retrospectively included. Patients were divided into two groups based on the presence of GGO: GGO adenocarcinoma and solid adenocarcinoma. Recurrence patterns at follow-up CT examinations were investigated and compared between the two groups. The effects of patient grouping on time to recurrence, postrecurrence survival (PRS), and overall survival (OS) were evaluated using Cox regression. Results Of 1019 patients (mean age, 62 years ± 9 [SD]; 520 women), 487 had GGO adenocarcinoma and 532 had solid adenocarcinoma. Recurrences occurred more frequently in patients with solid adenocarcinoma (36.1% [192 of 532 patients]) than in those with GGO adenocarcinoma (16.2% [79 of 487 patients]). Distant metastasis was the most common mode of recurrence in the group with solid adenocarcinoma and all clinical stages. In clinical stage I GGO adenocarcinoma, all regional recurrences appeared as ipsilateral lung metastasis (39.2% [20 of 51]) without regional lymph node metastasis. Brain metastasis was more frequent in patients with clinical stage I solid adenocarcinoma (16.5% [16 of 97 patients]). The presence of GGO was associated with time to recurrence and OS (adjusted hazard ratio [HR], 0.6 [P < .001] for both). Recurrence pattern was an independent risk factor for PRS (adjusted HR, 2.1 for distant metastasis [P < .001] and 3.9 for brain metastasis [P < .001], with local-regional recurrence as the reference). Conclusion Recurrence patterns, time to recurrence, and overall survival differed between patients with and without ground-glass opacity at CT, and recurrence patterns were associated with postrecurrence survival. © RSNA, 2023 Supplemental material is available for this article.

Patients who undergo transcatheter aortic valve replacement (TAVR) are at risk for new-onset arrhythmia (NOA) that may require permanent pacemaker (PPM) implantation, resulting in decreased cardiac function. We aimed to investigate the factors that are associated with NOA after TAVR and to compare pre- and post-TAVR cardiac functions between patients with and without NOA using CT-derived strain analyses. We included consecutive patients who underwent pre- and post-TAVR cardiac CT scans six months after TAVR. New-onset left bundle branch block, atrioventricular block, and atrial fibrillation/flutter lasting over 30 days after the procedure and/or the need for PPM diagnosed within 1 year after TAVR were regarded as NOA. Implant depth and left heart function and strains were analyzed using multi-phase CT images and compared between patients with and without NOA. Of 211 patients (41.7

OBJECTIVE:To propose standardized MRI-proton density fat fraction (PDFF) cutoff values for diagnosing hepatic steatosis, evaluated using contemporary PDFF measuring methods in a large population of healthy adults, using histologic fat fraction (HFF) as the reference standard.MATERIALS AND METHODS:A retrospective search of electronic medical records between 2015 and 2018 identified 1063 adult donor candidates for liver transplantation who had undergone liver MRI and liver biopsy within a 7-day interval. Patients with a history of liver disease or significant alcohol consumption were excluded. Chemical shift imaging-based MRI (CS-MRI) PDFF and high-speed T2-corrected multi-echo MR spectroscopy (HISTO-MRS) PDFF data were obtained. By temporal splitting, the total population was divided into development and validation sets. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of the MRI-PDFF method. Two cutoff values with sensitivity > 90% and specificity > 90% were selected to rule-out and rule-in, respectively, hepatic steatosis with reference to HFF ≥ 5% in the development set. The diagnostic performance was assessed using the validation set.RESULTS:Of 921 final participants (624 male; mean age ± standard deviation, 31.5 ± 9.0 years), the development and validation sets comprised 497 and 424 patients, respectively. In the development set, the areas under the ROC curve for diagnosing hepatic steatosis were 0.920 for CS-MRI-PDFF and 0.915 for HISTO-MRS-PDFF. For ruling-out hepatic steatosis, the CS-MRI-PDFF cutoff was 2.3% (sensitivity, 92.4%; specificity, 63.0%) and the HISTO-MRI-PDFF cutoff was 2.6% (sensitivity, 88.8%; specificity, 70.1%). For ruling-in hepatic steatosis, the CS-MRI-PDFF cutoff was 3.5% (sensitivity, 73.5%; specificity, 88.6%) and the HISTO-MRI-PDFF cutoff was 4.0% (sensitivity, 74.7%; specificity, 90.6%).CONCLUSION:In a large population of healthy adults, our study suggests diagnostic thresholds for ruling-out and ruling-in hepatic steatosis defined as HFF ≥ 5% by contemporary PDFF measurement methods.