P1758 - Derivation, Interobserver Agreement and Impact of Pre-Surgical EUS-Confocal Laser Endomicroscopy (CLE) Vascular Characteristics for Risk Stratification of IPMNs

Ahmed RM. Abdelbaki, MBBCh¹, Matthew Leupold, MD¹, Stacey Culp, PhD², Thiruvengadam Muniraj, MD³, Damien Tan, ⁴, Jorge D. Machicado, MD⁵, Anjuli Luthra, MD⁶, Erica Park, MD¹, Wei Chen, ¹, Ashwini Esnakula, MBBS¹, Phil Hart, MD¹, Somashekar G Krishna, MD^1
1The Ohio State University Wexner Medical Center, Columbus, OH; ²Ohio State University, Columbus, OH; ³Yale New Haven Health, New Haven, CT; ⁴Singapore General Hospital, Central Region, Singapore; ⁵University of Michigan Health, Ann Arbor, MI; ⁶Moffitt Cancer Center, Tampa, FL

Introduction: EUS-nCLE enables real-time in vivo visualization of papillae for risk-stratification of IPMNs. Progressive vascular changes in branch duct (BD)-IPMNs have not been previously evalauted. Capillary level characteristics are lost in post-resection surigcal histopathology due to tissue processing. We sought to derive and evaluate pre-surgical in vivo EUS-nCLE papillary and vascular characteristics for the prediction of high-grade dysplasia/invasive carcinoma (HGD-IC; advanced neoplasia) in IPMNs.

Methods: Subjects from two prospective studies evaluating EUS-nCLE for pancreatic cyst diagnosis were included if they had both papillary and vascular features on nCLE imaging and a definitive histopathological diagnosis. Four blinded external observers reviewed nCLE videos to classify dysplasia (HGD-IC vs. low-grade). Subsequently, two internal observers assessed vascular patterns (simple vs. complex branching), density (low vs. high), morphology (tortuous vs.not), and overall classification (simple vs. complex) to detect HGD-IC. The four observers were then trained on these vascular patterns and reassessed the IPMNs using only nCLE vascular imaging.

Results: Among 49 BD-IPMNs (HGD-IC in 17), the mean IPMN size was 3.31±0.83 cm, mean age of subjects was 68.1 ± 9.3 years (51.0% male).

In the observer group (n=4), the sensitivity, specificity, and accuracy for nCLE papillary imaging and detection of HGD-IC were as follows:
• Observer 1: 77%, 69%, 71%
• Observer 2: 53%, 75%, 67%
• Observer 3: 35%, 78%, 63%
• Observer 4: 65%, 59%, 61%

After adding vascular features to the papillary level analysis, the diagnostic yield for detecting HGD-IC improved for each observer. Compared to detection based solely on papillary level characteristics, the improvement in the rate of detection was as follows:
• Observer 1: from 77% to 88% (p = 0.50)
• Observer 2: from 53% to 76% (p = 0.16)
• Observer 3: from 35% to 76% (p = 0.02)
• Observer 4: from 65% to 88% (p = 0.11)

The mean improvement in the detection of HGD-IC was from 56% to 82%.

Discussion: In this first-ever evaluation of pre-surgical vascular characteristics, nCLE imagin demonstrates that the presence of complex vascularity, when combined with papillary features, may enhance the detection of HGD-IC in IPMNs. However, additional exploration, refinement, and training on vasculature is still needed to further improve its performance across observers. Larger validation studies are also warranted to confirm these findings.



Disclosures:


Ahmed RM. Abdelbaki, MBBCh¹, Matthew Leupold, MD¹, Stacey Culp, PhD², Thiruvengadam Muniraj, MD³, Damien Tan, ⁴, Jorge D. Machicado, MD⁵, Anjuli Luthra, MD⁶, Erica Park, MD¹, Wei Chen, ¹, Ashwini Esnakula, MBBS¹, Phil Hart, MD¹, Somashekar G Krishna, MD¹. P1758 - Derivation, Interobserver Agreement and Impact of Pre-Surgical EUS-Confocal Laser Endomicroscopy (CLE) Vascular Characteristics for Risk Stratification of IPMNs, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.