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Congress: ECR25
Poster Number: C-21834
Type: Poster: EPOS Radiologist (scientific)
Authorblock: A. Horr, P. Langguth, L-P. Schmill, O. Jansen, S. Aludin; Kiel/DE
Disclosures:
Agreen Horr: Nothing to disclose
Patrick Langguth: Speaker: Philips
Lars-Patrick Schmill: Nothing to disclose
Olav Jansen: Nothing to disclose
Schekeb Aludin: Speaker: Philips
Keywords: Lung, Pulmonary vessels, CT, Contrast agent-intravenous, Diagnostic procedure, Localisation, Embolism / Thrombosis, Ischaemia / Infarction
Methods and materials

In this retrospective single-center study, 31 patients who underwent contrast-enhanced SDCT for clinically suspected PE between April 2021 and April 2024 were analyzed. All patients had a confirmed PE on CT imaging and showed evidence of PI. A control group (K-group) of 31 patients without PE or PI was included for comparison. The study was approved by the Ethics Committee of the Christian-Albrechts-University of Kiel (D 567/18, Amendment dated October 7, 2024). All CT examinations were performed using a 128-slice spectral detector CT (CT 7500, Philips Healthcare). Each patient received 50 mL of iodinated contrast agent (Imeron® 300 mg/mL), followed by 40 mL of saline solution, administered via a venous access at a flow rate of 4 mL/s. Image acquisition was performed with bolus tracking at a threshold of 180 HU in the pulmonary trunk. Spectral image data were reconstructed with a slice thickness of 2 mm.

Pulmonary perfusion was analyzed using iodine density maps generated from the SDCT datasets. Peripheral iodine concentration was measured in all lung segments by placing regions of interest (ROIs). For each segment, four subpleural ROIs (50 mm² ± 5 mm²) were positioned within a maximum distance of 2 cm from the pleura, deliberately avoiding measurements near the ribs to minimize artifacts (see Figure 1).

In segments exhibiting a PI, the iodine concentration was specifically measured in the peripheral zone of the infarct, with a minimum distance of 1 cm from the core of the infarct area being maintained to reduce the influence of any inflammatory hyperperfusion. The iodine concentration was then correlated with the occlusion site (central vs. lobar vs. segmental vs. subsegmental) as well as with the presence of PI. To account for physiological perfusion differences, reference values for the individual pulmonary segments were first obtained from the K-group, and the values in the PI-group were then normalized to these reference values to form a ratio, thereby improving the accuracy of detecting pathological perfusion changes.
GALLERY