S0975 EUS Elastography: Initial Experience at the Safety Net Hospital

Abstract

INTRODUCTION: Endoscopic Ultrasound Elastography (EUS-E) is increasingly used to augment EUS imaging and to direct EUS-guided tissue acquisition. The experience with EUS-E using new generation EUS processors is limited. We aimed to evaluate the diagnostic utility of EUS-E in a variety of gastrointestinal lesions in a diverse safety net patient population. METHODS: The EUS database was retrospectively queried for EUS-E procedures performed from 08/15/2019, when EUS-E first became available at our institution, to 06/15/2020. EUS-E was performed with a linear echoendoscope (GF-UCT180, Olympus USA) and Hitachi Aloka ProSound F75 processor (Olympus USA). The queried data included EUS-E strain ratios (SR), final pathologic diagnosis, EUS findings, and patient demographics. Where multiple SR obtained, the mean was reported. Previously reported SR cutoff of 18 was used to define high risk lesions. RESULTS: EUS-E was performed in 19 patients (mean age 55 y; 28–77; 9 men and 10 women); mean lesion size 3.3 cm ± 1.3 cm. Pancreatic masses, lymph node, thyroid mass, hepatic mass, gastric mass were among lesions analyzed. High risk lesions based on EUS-E were confirmed by cytology/tissue pathology to be five pancreatic adenocarcinomas, one pancreatic intraepithelial neoplasia, and one intraductal papillary mucinous neoplasia with mean SR 41.5 ± 22.8 (0.48–81.0). EUS-E with EUS-FNA/B as a diagnostic standard had the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of 87.5%, 71.4%, 77.8%, 83.3%, and 80.0%, respectively (Table 1). One heterogeneous lesion with SR 0.48 was later determined to be pancreatic adenocarcinomaTable 1. Benign pathology was found in a peri-pancreatic mass, SR 3.8, a pancreatic head mass, SR 13.7, a pancreatic body mass, SR 0.75, a gastric subepithelial lesion, SR 0.71, and a hepatic lesion, SR 0.33. Two pancreatic lesions with benign pathology, SR 22.7 and 42.8, are now pending repeat EUS-FNB. Pathology was non-diagnostic on a thyroid mass with SR 9.5 and a pancreatic body mass with SR 1.4. Biopsy was not performed on two lesions, a peri-pancreatic lymph node with SR 25.3 and a peri-pancreatic splenule with SR 45.3. CONCLUSION: Our initial experience suggests that EUS-E could be a useful adjunct to EUS imaging and EUS-guided tissue acquisition. Lesions with benign pathology and high strain ratios should be considered for repeat sampling and closely followed.