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Preoperative CT or MRI images were reviewed by two reviewers. Imaging and clinicopathologic features of s-PDA were compared according to the presence of EPE. Cox regression analyses were performed to identify predictors of recurrence.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Results<\/jats:title>\n            <jats:p>142 patients (77 men; 64.7\u2009\u00b1\u20099.3 years) who underwent preoperative CT (<jats:italic>n<\/jats:italic>\u2009=\u2009134) or MRI (<jats:italic>n<\/jats:italic>\u2009=\u2009115) were included. Duct dilatation was a common imaging finding of s-PDA (CT: 75.4%, MRI: 82.6%). Of the 142 patients, 21.8% (31\/142) had no EPE, while 78.2% (111\/142) had EPE. Tumor size on CT (14.3\u2009\u00b1\u20098.7\u00a0mm vs. 18.2\u2009\u00b1\u20096.5\u00a0mm, <jats:italic>p<\/jats:italic>\u2009=.01) and abutment or encasement of superior mesenteric vein (13.8% vs. 40.9%, <jats:italic>p<\/jats:italic>\u2009=.02) on CT were different according to absence or presence of EPE. Recurrence was more common in s-PDA with EPE (32.3% [10\/31] vs. 53.2% [59\/111], <jats:italic>p<\/jats:italic>\u2009=.04). Pathologic tumor size (HR 1.103, 95% CI 1.020\u20131.193, <jats:italic>p<\/jats:italic>\u2009=.01), tumor size on MRI (HR 1.044, 95% CI 1.001\u20131.090, <jats:italic>p<\/jats:italic>\u2009=.048), and extrapancreatic neural invasion on MRI (HR 3.341, 95% CI 1.564\u20137.140, <jats:italic>p<\/jats:italic>\u2009=.002) were significant predictors of recurrence.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>Conclusion<\/jats:title>\n            <jats:p>Even in s-PDA, tumors with EPE are larger and show higher recurrence rates. Imaging features are important for predicting presence of EPE.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1007\/s00261-025-04831-0","type":"journal-article","created":{"date-parts":[[2025,2,13]],"date-time":"2025-02-13T22:40:26Z","timestamp":1739486426000},"page":"4168-4180","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Small pancreatic ductal adenocarcinoma (\u2264\u20092\u00a0cm): different imaging and clinicopathologic features according to extrapancreatic extension"],"prefix":"10.1007","volume":"50","author":[{"given":"Rae Rim","family":"Ryu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jung Hoon","family":"Kim","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junghoan","family":"Park","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sungjun","family":"Hwang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2025,2,14]]},"reference":[{"key":"4831_CR1","doi-asserted-by":"publisher","unstructured":"Siegel RL, Miller KD, Wagle NS, Jemal A. 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