(HP08) Comparison of 2-dimensional Imaging to 3-dimensional Modeling of Intrahepatic Portosystemic Shunts Using Computed Tomography Angiography

Abstract:

Background: Computed tomography angiography (CTA) is used to help diagnose intrahepatic portosystemic shunts (IHPSS). Caudal vena cava (CVC) measurements are typically obtained from 2-dimensional (2D) imaging to aid in stent selection for transcatheter intervention.
Hypothesis/

Objectives: 3-dimensional (3D) vascular models can be generated for IHPSS, and CVC measurements will not differ significantly between 2D images and 3D models.
Animals: CTA datasets of IHPSS from client-owned dogs at University of Georgia between 2016-2022.

Methods: Materialise Mimics 25.0 and 3-matic 17.0 were used for 3D modeling. CVC diameters were measured in 2D coronal and axial planes 20mm cranial and caudal from the shunt ostium, and were compared to CVC diameters from 3D models. Length was measured in the 2D coronal plane between midpoints of each diameter, and compared to 3D length. Data are presented as mean(standard deviation). Intra-class correlation coefficients (ICC) were performed.

Results: 3D models were generated for 32 IHPSS (15 right-, 12 left-, and 5 central-divisional). 2D coronal and axial diameter measurements were 16.7mm(5.6) and 15.5mm(4.2) cranial, 14.9mm(4.2) and 14.3mm(3.7) caudal. 3D diameter measurements were 15.3mm(4.4) cranial and 14.0mm(3.6) caudal. 2D length was 61.5mm(7.1) compared to 3D 59.9mm(7.2). ICCs comparing 2D and 3D diameters were all > 0.80, indicating very good agreement, with good agreement between 2D and 3D length.

Conclusions and clinical importance: 3D IHPSS models can be generated using modeling software, and measurements from 3D models are consistent with 2D planar imaging. 3D IHPSS models are accurate representations of patient-specific disease. Future directions include utilizing models for pre-procedural planning.