Assessment of Pulmonary Vascular Stent Morphology Using Intra-procedural Cone-Beam CT in Fibrosing Mediastinitis: Imaging Agreement and Clinical Implications.

Rationale

AND

Objectives

Percutaneous Pulmonary Vascular Stent Angioplasty (PPVSA) is a key treatment for pulmonary vascular stenosis in Fibrosing Mediastinitis (FM). This study evaluated the added value of intraoperative cone-beam computed tomography (CBCT) beyond conventional angiography for post-stenting assessment during PPVSA.

Materials And Methods

This retrospective single-center study included 54 consecutive FM patients who underwent PPVSA between August 2021 and May 2024, comprising 114 stents (99 arterial and 15 venous). All patients underwent intraoperative CBCT, angiography, and follow-up computed tomography pulmonary angiography (CTPA) for assessment of stent geometry. Agreement between imaging modalities was evaluated using correlation, Bland-Altman, and reproducibility analyses. Associations between CBCT-derived parameters, hemodynamic outcomes, and stent patency were further explored.

Results

Among 54 patients (57.26 ± 11.47 years; 17 females [31.48%]), CBCT demonstrated excellent correlation with first follow-up CTPA. For maximum stent diameter, the correlation between CBCT and CTPA was r = 0.99, compared with r = 0.94 for angiography. For minimum stent diameter, the corresponding correlations were r = 0.99 and r = 0.85, respectively (all p < 0.001). Bland-Altman analysis showed smaller measurement bias and narrower limits of agreement for CBCT than for angiography. During a median imaging follow-up of 614.50 days, in-stent restenosis occurred in 15.79% of stents, whereas complete stent occlusion occurred in 1.75% of stents. Stents with a minimum-to-maximum diameter ratio <80% showed higher restenosis rates than those with a ratio ≥80% (24.00% vs. 9.38%, p = 0.017). In addition, among pulmonary arterial stents, a CBCT-derived stent relief index was positively correlated with trans-lesional systolic pressure gradient reduction (r = 0.249, p = 0.033).

Conclusion

Intraoperative CBCT provides reliable assessment of stent geometry during PPVSA. In addition to demonstrating strong agreement with first follow-up CTPA, CBCT-derived morphologic parameters may be associated with procedural hemodynamic improvement and may provide supplemental information regarding subsequent stent patency and long-term outcomes.