title: Evolution of incidental branch-duct intraductal papillary mucinous neoplasms of the pancreas: A study with magnetic resonance imaging cholangiopancreatography.
abstract: OBJECTIVE
  To investigate the type and timing of evolution of incidentally found branch-duct intraductal papillary mucinous neoplasms (bd-IPMN) of the pancreas addressed to magnetic resonance imaging cholangiopancreatography (MRCP) follow-up.
  
  
  METHODS
  We retrospectively evaluated 72 patients who underwent, over the period 2006-2016, a total of 318 MRCPs (mean 4.4) to follow-up incidental, presumed bd-IPMN without signs of malignancy, found or confirmed at a baseline MRCP examination. Median follow-up time was 48.5 mo (range 13-95 mo). MRCPs were acquired on 1.5T and/or 3.0T systems using 2D and/or 3D technique. Image analysis assessed the rates of occurrence over the follow-up of the following outcomes: (1) imaging evolution, defined as any change in cysts number and/or size and/or appearance; and (2) alert findings, defined as worrisome features and/or high risk stigmata (e.g., thick septa, parietal thickening, mural nodules and involvement of the main pancreatic duct). Time to outcomes was described with the Kaplan-Meir approach. Cox regression model was used to investigate clinical or initial MRCP findings predicting cysts changes.
  
  
  RESULTS
  We found a total of 343 cysts (per-patient mean 5.1) with average size of 8.5 mm (range 5-25 mm). Imaging evolution was observed in 32/72 patients (44.4%; 95%CI: 32-9-56.6), involving 47/343 cysts (13.7%). There was a main trend towards small (< 10 mm) increase and/or decrease of cysts size at a median time of 22.5 mo. Alert findings developed in 6/72 patients (8.3%; 95%CI: 3.4-17.9) over a wide interval of time (13-63 mo). No malignancy was found on endoscopic ultrasound with fine-needle aspiration (5/6 cases) or surgery (1/6 cases). No clinical or initial MRCP features were significantly associated with changes in bd-IPMN appearance (P> 0.01).
  
  
  CONCLUSIONS
  Changes in MRCP appearance of incidental bd-IPNM were frequent over the follow-up (44.4%), with relatively rare (8.3%) occurrence of non-malignant alert findings that prompted further diagnostic steps. Changes occurred at a wide interval of time and were unpredictable, suggesting that imaging follow-up should be not discontinued, though MRCPs might be considerably delayed without a significant risk of missing malignancy.
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Rossano
authors.initials: R
authors.lastname: Girometti
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pravisani
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Sergio Giuseppe
authors.initials: SG
authors.lastname: Intini
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Isola
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cereser
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Risaliti
authors.affiliation: Rossano Girometti, Lorenzo Cereser, Chiara Zuiani, Institute of Diagnostic Radiology, Department of Medical and Biological Sciences, University of Udine, University Hospital "S. Maria della Misericordia", p.le S. Maria della Misericordia, 15-33100 Udine, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Zuiani
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D049448:Cholangiopancreatography, Magnetic Resonance; D018450:Disease Progression; D005260:Female; D006801:Humans; D033162:Incidental Findings; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018297:Neoplasms, Cystic, Mucinous, and Serous / Q000000981:diagnostic imaging* / Q000473:pathology; D010183:Pancreatic Ducts / Q000000981:diagnostic imaging* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013997:Time Factors
keywords: Branch-duct intraductal papillary mucinous neoplasm; Cysts; Follow-up; Magnetic resonance cholangiopancreatography; Pancreas