RPS 904 - Imaging of pulmonary embolism and pulmonary hypertension

Author Block: H-J. Meyer¹, S. Zimmermann¹, J. Borggrefe², A. Surov²; ¹Leipzig/DE, ²Minden/DE
Purpose: Accurate prediction of short-term mortality in acute pulmonary embolism (APE) is very important. The aim of the present study was to analyze the prognostic role of radiomics values of epicardial adipose tissue (EAT) in APE.
Methods or Background: Overall, 508 patients were included into the study, 209 female (42.1%), mean age, 64.7 ± 14.8 years. 4.6%and 12.4% died (7- and 30-day mortality, respectively). For external validation, a cohort of 186 patients was further analysed. 20.2% and 27.7% died (7- and 30-day mortality, respectively). CTPA was performed at admission for every patient before any previous treatment on multi-slice CT scanners. A trained radiologist, blinded to patient outcomes, semiautomatically segmented the EAT on a dedicated workstation using ImageJ software. Extraction of radiomic features was applied using the pyradiomics library. Patients were randomly assigned to a training and a validation cohort with a ratio of 7:3. We characterized two models (30-day and 7-day mortality).
Results or Findings: We fitted the characterized models to a validation cohort (n = 169) in order to test accuracy of our models. We observed an AUC of 0.776 (CI 0.671-0.881) and an AUC of 0.724 (CI 0.628-0.820) for the prediction of 30-day mortality and 7-day mortality, respectively. The overall percentage of correct prediction in this regard was 88% and 79% in the validation cohorts. Lastly, the AUC in an independent external validation cohort was 0.721 (CI 0.633-0.808) and 0.750 (CI 0.657-0.842), respectively.
Conclusion: Radiomics parameters of EAT are strongly associated with mortality in patients with APE.
Limitations: It is a retrospective study, which should be evaluated in a prospective multi center analysis.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Nr. 145/21, Ethics Committee, Otto-von-Guericke University of Magdeburg, Magdeburg, Germany)

Author Block: H. Shang, Y. Gao, D. D. Tian, K. Li, X. Zhang, P. Cao; Xi'an/CN
Purpose: To assess the viability of using a low dose of iodine contrast medium (CM) and slow injection rate in single-energy 40keV CT imaging for pulmonary artery angiography (CTA).
Methods or Background: Seventy patients, clinically suspected of pulmonary embolism and treated between January and September 2024, were randomly assigned to either an experimental group (35 patients) or a control group (35 patients). The experimental group underwent imaging at 100kV with 6ml CM at an injection rate of 2.5ml/s, triggered at a threshold of 60HU. The control group was imaged at 120kV with 35-40ml CM at an injection rate of 3.5ml/s, triggered at 80HU. All scans targeted the pulmonary artery trunk and utilized the non-ionic, water-soluble iodine contrast agent iomeprol (400mg/ml). Both groups were scanned under free breathing conditions. Image quality was subjectively rated on a 5-point scale, and objectively assessed based on pulmonary vascular enhancement, CT values, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and radiation dose metrics including dose-length product (DLP) and volumetric CT dose index (CTDIvol).
Results or Findings: The CT values of the main pulmonary artery showed no significant difference between groups (P>0.05). However, the experimental group demonstrated significantly higher CT values in the right upper, middle, interlobar, and lower lobe arteries, as well as the left upper and lower lobe arteries (P < 0.05). Although the experimental group exhibited higher noise, SNR, and CNR, these differences were not statistically significant (P>0.05). The experimental group also had significantly lower CTDIvol and DLP values compared to the control group (P<0.05). Subjective image quality evaluations revealed no significant difference between the two groups (P>0.05).
Conclusion: CTA of the pulmonary artery at 40keV with 6ml CM and an injection rate of 2.5ml/s can provide diagnostic image quality.
Limitations: Not applicable
Funding for this study: Not applicable
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Not applicable

Author Block: L. Shen, J. Lu, C. Zhou, Z. Bi, X. Ye, M. Zeng, W. Mingliang; Shanghai/CN
Purpose: To assess the effectiveness of artificial intelligence software (AI) in detecting pulmonary embolism (PE) using low-dose CT pulmonary angiography (CTPA) enhanced by deep learning reconstruction (DLR) and contrast-enhancement boost (CE-boost) technique.
Methods or Background: This prospective two-center study included 180 patients who underwent CTPA for suspected PE. Patients were randomly divided into two groups: the routine CTPA group with 50 mL contrast medium (CM) was reconstructed using HIR, and the low-dose CTPA group with 25 mL CM was reconstructed using DLR. The CE-boost was additionally performed to generate DLR-boost images in the low-dose group. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of pulmonary arteries were quantitatively assessed. For qualitative image quality assessment, two experienced radiologists independently rated CT images (5, best; 1, worst). A subset of 46 randomly selected patients in each group (1:1 ratio) were evaluated by the AI software (Discover PE, uAI) for the presence of PE. Reference standard was established by expert consensus. The diagnostic accuracy (sensitivity and specificity) of the AI interpretations were compared between methods by bootstrapping.
Results or Findings: DLR-boost images produced lower noise, higher SNR and CNR, and superior subjective image quality compared to HIR images in the routine group (p < 0.05). For detecting PE, compared to HIR images, DLR-boost images showed comparable sensitivity (97.67% vs. 93.02%, p < 0.001), and equivalent specificity of (both 100.00%, p > 0.05). The effective dose of the double-low group and the routine group was 1.19 ± 0.45 mSv and 2.69 ± 0.49 mSv, respectively.
Conclusion: DLR-boost significantly enhances CTPA image quality at reduced radiation and contrast doses. AI software achieves diagnostic performance comparable to traditional reconstruction methods, supporting its use in clinical practice.
Limitations: N/A
Funding for this study: This study has received funding by Shanghai Anticancer Association EYAS PROJECT (Grant NO. SACA CY22C15).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Ethics Committee of Shanghai Geriatric Medical Center(B2024-009).

Author Block: A. Cisarri, A. Valentini, E. M. Bassi, I. Fiorina, A. D'Onorio De Meo, G. Rodolico, M. Zacchino, K. Ellena, L. Preda; Pavia/IT
Purpose: Chronic thromboembolic pulmonary disease (CTEPD) is a rare condition in which patients may or may not develop pulmonary hypertension. Although both groups are treated in the same way, through pulmonary thromboendarterectomy (PEA), the pathogenic mechanisms by which some patients develop pulmonary hypertension while others do not have yet to be clarified. The study aims to investigate vascular changes using AI-driven quantification of pre- and post-operative CT scans in patients undergoing PEA.
Methods or Background: The study analyzed 35 patients with chronic thromboembolic disease, divided into three groups based on preoperative mean pulmonary arterial pressure (mPAP), from 2017-2022. Pre- and post-operative CT scans of 22 of these patients were analyzed with AI-software to quantify vascular morphology, including vessel number, diameter, and blood volume at various pleural depths. Hemodynamic parameters such as mPAP and pulmonary vascular resistance (PVR) were also assessed.
Results or Findings: No significant differences in vascular quantification parameters were observed between patient groups pre-operatively. Post-treatment analysis showed a reduction in the number of small vessels (p=0.0065) and blood volume of small vessels (BV5) at 24 mm depth (p=0.036), with an increase in mean vessel diameter (p=0.0005). A significant correlation was found between BV5 reduction and PVR improvement (p=0.01).
Conclusion: CT quantification revealed significant post-operative vascular changes in CTEPD patients, especially in the medium-caliber vasculature. The findings suggest that PVR reduction is primarily linked to the reperfusion of larger vessels, with limited improvement in smaller vessel volumes. Future studies should explore these parameters as potential biomarkers for diagnosis and prognosis in CTEPD.
Limitations: The small sample size and limited postoperative follow-up restrict the study’s ability to generalize findings. Further prospective studies with larger cohorts are needed.
Funding for this study: No funding
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Approved

Author Block: W. Xu, L. Xi, A. Liu, M. Liu, S. Zhao; Beijing/CN
Purpose: We aim to study the new morphological markers of Chronic Thromboembolic Pulmonary Disease (CTEPD) and chronic thromboembolic pulmonary hypertension (CTEPH) on computed tomography pulmonary angiography (CTPA).
Methods or Background: We retrospectively enrolled CTEPH, CTEPD patients, and control group from January 2019 to October 2023 in our hospital. The morphological metrics including pulmonary blood volume, tortuosity, and fractal dimension (FD) on CTPA were automatically quantified on an Artificial Intelligence workstation. We compared these metrics among three groups and assessed their correlation with hemodynamics.
Results or Findings: A total of 190 participants (97 men, 56.2±10.9 years old) including 116 CTEPH patients ,54 CTEPD patients and 20 control enrolled in this study. The pulmonary artery tortuosity in the control group, CTEPD group, and CTEPH group showed a gradually increased progressively (1.07 [1.06–1.10] vs. 1.10 [1.07–1.14] vs. 1.14 [1.10–1.18], P<0.01). There was a positive correlation between pulmonary artery tortuosity and mean pulmonary artery pressure (r=0.47, P<0.01), pulmonary vascular resistance (r=0.44, P<0.01). Additionally, the volume of small and medium-sized pulmonary arteries was significantly higher in CTEPD patients compared to those with CTEPH (P<0.01). FD among three groups was comparable(p>0.05).
Conclusion: Pulmonary arterial tortuosity on CTPA is a crucial imaging biomarker for distinguishing between CTEPH and CTEPD. The preservation of normal volumes in the small and medium-sized pulmonary arteries observed in CTEPD patients implies that this feature could be a key determinant in maintaining normal resting pulmonary artery pressure.
Limitations: First, it was a single-center investigation with a small cohort of CTEPD patients and controls, and the non-normal distribution limits the generalizability of our findings. Larger studies with more diverse populations are needed to validate our results. Secondly, there is a need for further refinement in the precision of pulmonary vessel segmentation.
Funding for this study: This work was supported by This study is supported by the National Natural Science Foundation of China (82272081), Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2021-I2M-1-049, 2022-I2M-C&T-B-109). All authors have nothing to disclose.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This single-center study was approved by the hospital’s Ethics Committee (2022-KY-048) and was performed in accordance with the Declaration of Helsinki.

Author Block: E. Pershina, D. Shchekochikhin, A. Oganesyan; Moscow/RU
Purpose: To assess diagnostic value of DECT versus V/Q SPECT for CTEPH detection in PAH patients in Moscow Pulmonary Hypertension Center.
Methods or Background: DECT with the calculation of iodine maps and V/Q SPECT were performed in 29 patients (f/m - 9/13; age 65 ±10) with PAH and risk factors for CTEPH. All patients underwent right heart catheterization for PAH confirmation. CTA analysis included the number and level of vessel occlusions together with the presence and size of lung perfusion defects on iodine maps and CT signs of right heart failure.
Results or Findings: 21 of 29 patients (72,4%) demonstrated CTA features of possible CTEPH such as intraluminal defects, enlarged pulmonary trunk, pulmonary mosaic patten. Iodine maps revealed perfusion defects of 19 patients (86%). Two patients (7%) had intraluminal irregular defects without perfusion defects by DECT. V/Q SPECT determined perfusion defects in 20 patients (69%). There was one case (3, 4%) with mismatch between iodine maps and V/Q SPECT. However, it was explained by the enlarged pressure on the right heart chambers due to the cava-caval (cava superior – cava inferior) venous anastomosis and hepatic veins abnormalities. Sensitivity for perfusion defects by DECT was 95% and specificity 100%. Furthermore, the mean radiation dose was significantly lower for DECT vs. V/Q-SPECT (p = 0.006). Spreading of perfusion defect had strong correlation with severity of right heart failure (r=0.2, p<0.05).
Conclusion: Pulmonary CTA with iodine mapping improves the detection of CTEPH. Iodine maps demonstrate high sensitivity and specificity in comparison with V/Q SPECT. According to our preliminary data DECT could be potentially implemented in future diagnostic PH algorithms at least on par with V/Q-SPECT. Further research is needed.
Limitations: Pregnant
Older 18 years
GFR>30 ml/min
Iodine allergic reaction
Funding for this study: No funding
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: The study was approved by local ethical committee.

Author Block: S. Gowda, R. Kothari, V. Raj; Bengaluru/IN
Purpose: Chronic thromboembolic pulmonary hypertension (CTEPH) is a severe complication of pulmonary embolism characterized by persistent pulmonary arterial hypertension due to unresolved thromboembolic obstructions. This study explores the development and validation of a CT based prognostic predictive model designed to simulate hemodynamic parameters and guide management in CTEPH patients.
Methods or Background: We retrospectively analysed the data of 1100 patients diagnosed with CTEPH. Integrated data consisted of clinical history, echocardiogram reports, right heart catheterisation reports if any, CT pulmonary angiogram studies and proposed management strategies. CT clot burden score, CT parameter score and Perfusion defect score was obtained in all the patients. Patients were contacted to review the clinical outcomes.
Results or Findings: Parameter scoring was seen to be useful in predicting hemodynamic parameters and outcomes. A cut-off of 3 is close to normal hemodynamic status (sPAP, accuracy of 76%), while a cut-off of 5 represents higher than normal values of mPAP. A score of ≥7 indicated increased risk of mortality.
Conclusion: The CT based prognostic predictive model represents a valuable tool in the management of CTEPH by integrating detailed imaging with clinical factors. We suggest this model can be a standard component of CTEPH patient evaluation and management especially when right heart catheterisation is contraindicated or not possible. Future studies should focus on prospective validation and integration into clinical practice to further refine its utility and impact in the management. It can be used to avoid right heart catheterisation and ventilation-perfusion scans in selected patients who meet the cut-off values, thereby reducing additional cost burden to the patients.
Limitations: Single centre study, which may also have an in-built case selection bias.
Small sample size to ascertain likelihood of mortality
Needs prospective validation to integrate into clinical practice
Funding for this study: No funding was provided for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study received institutional review board approval.

Author Block: L. Nardone¹, L. Cereser¹, G. Agati¹, P. Ciolli², T. Nadarević³, C. Cicciò⁴, A. Borghesi², R. Girometti¹, C. Zuiani¹; ¹Udine/IT, ²Brescia/IT, ³Rijeka/HR, ⁴Negrar/IT
Purpose: This study aimed to evaluate the diagnostic accuracy of contrast-enhanced CT imaging in classifying patients with pulmonary hypertension (PH) across international guidelines-derived clinical groups I-V. The analysis focused on quantifying the utility of CT in a blinded setting, comparing the results with those from the PH multidisciplinary team meeting (PH-MDTM).
Methods or Background: We retrospectively included 172 contrast-enhanced CT studies from patients with PH performed in two tertiary referral centers. Three chest-devoted radiologists, blinded to the clinical data, independently reviewed all the CTs, assigning probability percentages for each of the five PH groups. A consensus grouping hypothesis was reached by averaging the probabilities across readers, and this was compared with the PH-MDTM grouping. Accuracy and Cohen’s Kappa (k)-derived inter-reader agreement values with 95% confidence intervals (95% CI) were calculated. The readers’ discriminatory power between individual PH groups was evaluated through areas under the receiver operating characteristic curve (AUC) analyses.
Results or Findings: The expert-blinded consensus diagnosis agreed with the PH-MDTM in 124/172 cases (accuracy, 72%; k, 0.62; 95%CI, 0.50-0.70). When including the second most probable group, the readers correctly grouped 148/172 cases (accuracy, 86%; k, 0.81; 95%CI, 0.74-0.88). Discriminatory power analysis for individual groups demonstrated good readers’ performance, with AUC values ranging from 0.79-0.90 depending on the group.
Conclusion: This study highlights the value of contrast-enhanced CT in classifying PH according to clinical groups, with expert readers achieving substantial-to-almost perfect agreement with the PH-MDTM grouping and good discriminatory power for individual PH groups. The results suggest that CT imaging can serve as a reliable tool in the clinical work-up of PH patients, supporting its integration into multidisciplinary evaluations.
Limitations: Retrospective design, low number of group V PH cases.
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: The ethics committee notification can be found under the number IRB 250/2023.