RPS 1604 - Lung cancer screening and nodule assessment

Author Block: G. Dixon¹, V. Dattani¹, M. Jordan², J. Rodrigues¹; ¹Bath/UK, ²Coventry/UK
Purpose: Pulmonary nodules are frequently identified on non-screening CT chest scans. The management of pulmonary nodules in the UK is governed by the British Thoracic Society (BTS) Guidance 2015. Artificial intelligence can provide automated nodule identification and volumetry. The clinical and cost effectiveness of incorporating automated nodule detection into patient pathways are currently unclear.
Methods or Background: All CT scans including the thorax over one week in a single UK centre during March 2022 were identified and their original reports reviewed. CT scans were categorised as to whether the original report gave a BTS recommendation or not. Currently, patients without a BTS recommendation are assumed to undergo a full lung MDT discussion to determine the recommendation. A virtual nodule clinic was modelled whereby all patients with >1 nodule of >80mm3 identified using Veye Lung Nodules who did not receive a BTS recommendation in the original CT report were referred to a virtual nodule clinic. The cost of this approach was compared to current practice.
Results or Findings: 80/357 scans had > 1 pulmonary nodule >80mm3 identified using Veye Lung Nodules. 51/80 patients did not receive a BTS Guideline based recommendation in the original radiologist report. A potential cost saving of £9.48 per case to review these cases in a virtual lung nodule clinic was calculated. This represents a cost saving of £483.48 during the study period (one week) and a potential annual cost saving of between £25,141 and £36,854.
Conclusion: The study identified a potential cost saving of automated triage of lung nodules into a virtual lung nodule clinic.
Limitations: Further work is ongoing to model longitudinal costs of this cohort of patients.
Funding for this study: No specific funding was used for this study
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: N/A

Author Block: M. F. G. Konrad¹, E. Nischwitz¹, V. Palm¹, O. Von Stackelberg¹, A. Baca-Stera², K. Błasińska², M. Adamek³, J. Chorostowska-Wynimko², H-U. Kauczor¹; ¹Heidelberg/DE, ²Warsaw/PL, ³Gdansk/PL
Purpose: Exploration of the current status of institutional and technical factors of CT acquisition protocols applied in Europe that may affect the radiation exposure of screening participants in lung cancer screening procedures.
Methods or Background: To achieve an overview of the applied CT acquisition protocols in lung cancer screening across Europe, data were acquired from leading investigators responsible for the definition of CT acquisition protocols in the screening centres of the SOLACE consortium. Data regarding institutional and technical factors of CT acquisition protocols were collected through a baseline survey. All data embody the current status between June and October 2024.
Results or Findings: Survey responses of 16 screening centres from 10 European countries (Croatia, Czechia, Estonia, France, Greece, Hungary, Ireland, Italy, Poland and Spain) were received. In relation to institutional factors, the CT acquisition protocols are established and modified by personnel of multiple professional roles (radiologists, radiographers, medical physicists, manufacturer personnel). In eight of 16 (50 %) institutions the protocol is established by a multiprofessional team. CT protocols are mostly modifiable (88 %). Regarding technical factors, the number of detector rows in the z-direction ranges from 16 to 128. In 13 of 16 centres (81 %) automatic exposure control is applied. The applied reconstructed slice thickness and increment lies in the range of 0.625 - 1.25 mm.
Conclusion: Lung cancer screening in Europe within the SOLACE consortium is widely implemented reaching the technical limits of currently operated devices. The definition of CT acquisition protocols as a team effort and the possible modification of protocols are subjects of imaginable improvements.
Limitations: The brief survey data stems only from institutions with research focus.
Funding for this study: This project is co-funded under the EU4Health Programme 2021–2027 under grant agreement no. 101101187
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not a patient study

Author Block: L. D'Hondt¹, C. Haentjens¹, A. Snoeckx², K. Bacher¹; ¹Ghent/BE, ²Antwerp/BE
Purpose: In lung cancer screening (LCS), non-ideal positioning, changes in scan direction or scanogram angles are likely to occur due to the high turnover of participants and large volume of scans performed. Additionally, since we are dealing with healthy individuals, careful management of radiation dose is crucial. This study aims to systematically simulate how participant positioning and scanning parameters affect organ-specific radiation doses.
Methods or Background: Using the Alderson Rando phantom, we performed CT scans under varying conditions on two scanners (GE Revolution, Siemens SOMATOM Definition Flash) to establish automatic tube current modulation (ATCM) variations. ImpactMC Monte Carlo software simulated low-dose scans for 32 patient-specific voxel models, calculating percentage dose differences to lungs, heart, thyroid, liver, and female breasts. Deviations included lateral/vertical mispositioning (2cm increments), scan direction changes (craniocaudally, caudocranially), and varying scanogram angles (anteroposterior, posteroanterior, lateral, combined).
Results or Findings: Vertical deviations caused linear increase in organ doses when positioned closer to the tube during scanogram, with the GE scanner showing a 12-24% increase per 2cm deviations. For the Siemens scanner this linear increase was less pronounced (3-9% increase per 2cm deviation). Lateral mispositioning increased organ doses by <10% for both scanners.
Caudocranial scanning only increased thyroid doses by 15.8% for GE, while Siemens in fact showed a 19.7% decrease in thyroid dose and significant increases in lung (18.7%), heart (28.7%), liver (32.6%), and breast (27.9%) doses. For both scanners, the highest doses occurred with a posteroanterior scanogram. Siemens showed 72% dose reduction with dual scanogram, while GE showed minimally 34% reduction with an anteroposterior scanogram.
Conclusion: Non-ideal positioning and varying CT parameters can significantly affect organ doses, potentially underestimating the anticipated organ-specific doses and related radiation-induced cancer risk in LCS.
Limitations: Limitations are use of a phantom.
Funding for this study: Funding was provided by the FWO “Kom op tegen Kanker”-project for lung cancer screening research in Belgium. (Project number: G0B1922N).
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not applicable

Author Block: J. Bidzinska, J. Rymarowicz, K. Kobyłecka, K. Dziadziuszko, E. Szurowska, W. Rzyman; Gdansk/PL
Purpose: The aim of he study was to evaluate the results of the Pilot National Lung Cancer Screening program in the northern macroregion of Poland.
Methods or Background: After primary prevention, lung cancer screening is the strategy to reduce lung cancer-related mortality.
A total of 3068 asymptomatic volunteers between 50 and 74 years of age with a smoking history of at least 20 pack years underwent screening with the use of low-dose computed tomography of the chest.
The radiological nodule management protocol was designed for a 2-year follow-up. It was created specifically for the national program and implemented nationwide.
In the northern macroregion, LDCT was performed in 4 radiological centers. All radiologists were trained. The program included an anti-smoking intervention.
Results or Findings: At the time of submitting this abstract, 59 (1.92%) participants of the Program were diagnosed with lung cancer. In this group, 43 participants had resectable lung cancer, which is 73% of cases, including 22 women and 21 men. Few participants undergo diagnostic workups.
In addition, we assessed (or the analysis is ongoing) the lung cancer screening adherence rate, number and type of lung nodules, presence and severity of emphysema, CAC, incidental findings, and effectiveness of smoking cessation intervention.
Conclusion: Lung cancer screening with low-dose computed tomography of the chest is an effective tool for reducing lung cancer-related mortality.
LDCT is an effective tool for the identification of comorbidities.
It should be implemented as a National Lung Cancer Screening Strategy.
Limitations: Quality control in one of the sites revealed that the radiologist should be re-trained periodically.
Funding for this study: The program was financed by the Ministry of Health. The lung cancer prevention program was implemented in accordance with the competition regulations No. POWR.05.01.00-IP.00-010/19 Operational Program Knowledge Education and Development 2014-2020 Priority axis V Support for the health area Measure 5.1 Prevention programs.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Institutional Review Board of the Medical University of Gdańsk (NKBBN/72/2020).
During realisation of the program we asked all aprticipants for the consent to use of data in the future analyses and studies. Only 8 participanst did not consent.

Author Block: J. Jahn, F. B. Pallasch, M. Jung, M. Reisert, F. Bamberg, J. Weiß; Freiburg/DE
Purpose: Body composition (BC) is linked to outcomes in cardiovascular (CV) disease and cancer. BC is typically estimated from a 3rd lumbar slice, but the role of standardized chest heights and 3D volumes is unclear. Here, we used a fully automated deep learning network 1) to investigate the correlation between 2D single-slice areas and 3D whole-chest volumes and 2) to explore their association with mortality in heavy smokers.
Methods or Background: Using baseline data from the National Lung Screening Trial, BC was estimated on chest CT as skeletal muscle (SM), intramuscular (IMAT), and subcutaneous adipose tissue (SAT). Correlations between 2D thoracic vertebra slices and 3D chest volumes were explored. Associations between BC measures and all-cause mortality were assessed for both approaches, secondarily for CV and lung cancer mortality. Kaplan-Meier curves (categories <15%; 15-85%; >85%) and Cox regression models adjusted for demographics and CV risk factors were used.
Results or Findings: Among 23,361 individuals (mean age 61.4±5, 41.6% female), 1,616 (6.9%) all-cause deaths occurred over a median follow-up of 6.5 years. The highest correlation between 2D and 3D volumes was at T4 vertebra. For 3D volumes, lower SM, lower SAT, and higher IMAT were associated with higher mortality in Kaplan-Meier curves (p<0.01). Associations between these groups remained robust after multivariable adjustment (adjusted hazard ratio (aHR): 1.51, 95% CI 1.33-1.71, p<0.001; aHR: 1.21, 95% CI: 1.04-1.40, p<0.05; aHR: 1.68, 95% CI: 1.36-1.78, p<0.001, respectively). Largely similar patterns were found for 2D measures, CV, and lung cancer mortality.
Conclusion: BC measures independently predict mortality in heavy smokers beyond traditional clinical risk factors. 2D measures at T4 and 3D BC showed similar results, offering interchangeable use for identifying high-risk individuals in lung cancer screening, potentially enhancing personalized prevention.
Limitations: No limitations were identified.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: All National Lung Screening Trial participants provided written informed consent for the original trial and secondary use of the data was approved by the local IRB.

Author Block: J. Wang, L. Song, W. Song; Beijing/CN
Purpose: To investigate the performance of photon-counting detector (PCD) CT compared to conventional energy-integrating detector (EID) CT in identifying subsolid nodule (SSN) characteristics.
Methods or Background: Participants with SSNs who underwent same-day EID CT and PCD CT between October 2023 and April 2024 were prospectively included. The 1.0 mm EID CT images and, subsequently, 1.0, 0.4, and 0.2 mm PCD CT images were reviewed to assess image noise and subjective image quality on a 5-point Likert scale. SSN characteristics, including lobulation, spiculation, pleural retraction, air cavities, intra-nodular vessel sign, internal vascular changes, and heterogeneous solid components, were evaluated.
Results or Findings: Forty-eight participants (mean age: 56 ± 11 years; 16 males) with 89 SSNs were included. PCD CT significantly reduced radiation dose when using matched scans (1.79 ± 0.39 vs. 2.17 ± 0.57 mSv, P < 0.001). Compared to 1.0 mm EID CT, 1.0 mm PCD CT images exhibited significantly lower objective image noise and higher subjective image quality (all P < 0.001). Compared to EID CT, PCD CT demonstrated enhanced visualization of subtle characteristics, except for lobulation, with a 0.4 mm section thickness offering a favourable balance between ultra-high resolution and perceived image quality for radiologists.
Conclusion: PCD CT facilitated radiation dose reduction and outperformed conventional EID CT in terms of image quality and visualization of SSN characteristics.
Limitations: First, the primary focus was on SSNs with various imaging characteristics suggestive of malignancy; consequently, SSNs < 6 mm were not included in the study. Second, quantitative SSN analysis was not performed because the study aimed to explore the qualitative value of PCD CT in assessing SSN characteristics. Third, evaluation of nodules on a mediastinal window was not performed in this study. Fourth, not all SSNs yielded histopathologic results.
Funding for this study: This work has received funding by the National Natural Science Foundation of China (NSFC No. 82171934) and the National High Level Hospital Clinical Research Funding (2022-PUMCH-B-069).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The Institutional Review Board of our hospital approved this prospective study [I-23PJ1459].

Author Block: Y. Kim, T. Ha, S. You, J. Sun; Suwon/KR
Purpose: To evaluate the clinical outcomes of Korean Lung-RADS category 2b nodules in lung cancer screening and to compare the diagnostic performance between Korean Lung-RADS and Lung-RADS.
Methods or Background: This retrospective study included 2,908 participants who underwent low-dose chest CT scans at a single tertiary hospital between September 2019 and January 2024, as part of the Korean national lung cancer screening program. The modified Korean Lung-RADS added category 2b for nodules sized as category 3 or 4 but likely benign, aiming to reduce false positives. All CT scans were interpreted using the Korean Lung-RADS categorization (version 1.0 until 2021, version 1.1 from 2022, and version 2022 from 2024). To assess interobserver agreement, three radiologists independently reassessed each 2b nodule, indicating whether they would classify it as category 2b. Diagnostic performance comparisons were conducted using McNemar and permutation tests, while interobserver agreement was analyzed using multirater Fleiss κ statistics.
Results or Findings: 1,270 participants with confirmed diagnoses were finally included (mean age, 61.5 ± 5.2 years; 1,243 men). Lung cancer was identified in 28 participants (2.2%). Category 2b nodules were found in 24 participants (1.9%), with one diagnosed as lung cancer (4.2%) and the others benign (95.8%). Interobserver agreement was fair with a Fleiss kappa value of 0.36 (95% CI 0.17-0.79). In terms of diagnostic performance, Korean Lung-RADS showed significantly higher specificity (92.5%, 1,149 of 1,242) compared to Lung-RADS (90.7%, 1,126 of 1,242; p < 0.001), while sensitivity was comparable between Korean Lung-RADS (89.36%, 25 of 28) and Lung-RADS (92.8%, 26 of 28; p = 1).
Conclusion: Korean Lung-RADS category 2b helped reduce the false-positive rate in lung cancer screening. However, significant variability was observed among radiologists in classifying category 2b nodules.
Limitations: Retrospective study with small sample size.
Funding for this study: No
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This retrospective study was approved by the institutional review board, which waived the requirement for written informed consent (AJOUIRB-DB-2024-399).

Author Block: M. Balbi¹, S. Capelli², A. Caroli², N. C. Culasso¹, R. Senkeev¹, D. Morbidelli¹, G. Reboli¹, L. Righi³, A. Veltri¹; ¹Turin/IT, ²Ranica/IT, ³Orbassano/IT
Purpose: To evaluate the safety of CT-guided core needle biopsy (CNB) in patients with interstitial lung abnormalities (ILAs).
Methods or Background: Consecutive CT-guided pulmonary biopsies performed at the San Luigi Gonzaga Hospital (Orbassano, Italy) from February 2010 to December 2023 (n=3251) were retrospectively reviewed to identify patients with ILAs who underwent CNB for the assessment of a pulmonary lesion (n=73, case group). A control group of 73 CNB patients with no evidence of ILAs, matched for age, sex, emphysema severity, and lesion depth and dimensions, was selected to compare the complication rates. Logistic regression was performed to identify risk factors for complications within the case group, as well as to compare complication rates between the case and control groups.
Results or Findings: Complications occurred in 21/73 cases (29%) and 24/73 controls (33%), including 2 major complications in cases (3%) and 3 in controls (4%). Considering the overall occurrence of complications, there were no statistically significant differences between cases and controls, as assessed by Fisher’s exact test (p=0.72) and conditional logistic regression adjusted for matched variables (p=0.72). Among patient, procedural, and lesion-related data, three variables were found to be risk factors for complications in the case group based on univariate, multivariate, and stepwise logistic regression with bidirectional elimination, guided by the Akaike information criterion (AIC): longer time of the needle within the lung (odds ratio (OR), 1.17; 95% confidence interval (CI), 0.72–13.02; p = 0.126), needle traversal of ILAs (OR, 7.04; 95% CI, 2.07–26.28; p = 0.002), and multiple pleural passes (OR, 8.06; 95% CI, 1.26–70.46; p = 0.035).
Conclusion: CT-guided CNB in patients with ILAs showed safety comparable to patients without ILAs. However, crossing ILAs during the procedure may increase the complication risk.
Limitations: -Retrospective, single-center study
-Limited number of cases
-Lack of inter-reader agreement
Funding for this study: The study did not receive any funding.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The institutional review board (Comitato Etico Territoriale Interaziendale of the AOU Città della Salute e della Scienza di Torino) approved this retrospective observational case-control study and waived the requirement for written informed consent.

Author Block: K. Ye¹, B. Pan², J. Li³, Z. Pan², H. Yuan¹, N-J. Gong¹; ¹Beijing/CN, ²Shagnhai/CN, ³Fujian/CN
Purpose: To evaluate the image quality and lung nodule detectability of ultralow-dose CT (ULDCT) with adaptive statistical iterative reconstruction-V (ASiR-V) post-processed using a deep learning image reconstruction (DLIR)-based image domain compared to low-dose CT (LDCT) and ULDCT without DLIR.
Methods or Background: A total of 210 patients undergoing lung cancer screening underwent LDCT (mean ± SD, 0.81 ± 0.28 mSv) and ULDCT (0.17 ± 0.03 mSv) scans. ULDCT images were reconstructed with ASiR-V (ULDCT-ASiR-V) and post-processed using DLIR (ULDCT-DLIR). The quality of the three CT images was analyzed. Three radiologists detected and measured pulmonary nodules on all CT images, with LDCT results serving as references. Nodule conspicuity was assessed using a five-point Likert scale, followed by further statistical analyses.
Results or Findings: A total of 463 nodules were detected using LDCT. The image noise of ULDCT-DLIR decreased by 60% compared to that of ULDCT-ASiR-V and was lower than that of LDCT (p <0.001). The subjective image quality scores for ULDCT-DLIR (4.4[4,1, 4.6]) were also higher than those for ULDCT-ASiR-V (3.6[3.1, 3.9]) (p <0.001). The overall nodule detection rates for ULDCT-ASiR-V and ULDCT-DLIR were 82.1% (380/463) and 87.0% (403/463), respectively (p <0.001). The percentage difference between diameters >1 mm was 2.9% (ULDCT-ASiR-V vs. LDCT) and 0.5% (ULDCT-DLIR vs. LDCT) (p =0.009). Scores of nodule imaging sharpness on ULDCT-DLIR (4.0 ± 0.68) were significantly higher than those on ULDCT-ASiR-V (3.2 ± 0.50) (p <0.001).
Conclusion: DLIR-based image domain improves image quality, nodule detection rate, nodule imaging sharpness, and nodule measurement accuracy of ASiR-V on ULDCT.
Limitations: Only ASiR-V algorithm was evaluated, and more different IR algorithms should be included in the future.
Funding for this study: With improved image quality and a higher nodule detection rate, deep learning-based image domain reconstruction is beneficial in facilitating the use of ultralow-dose CT in lung cancer screening.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Peking university third hospital review board