MRI follow-up for pancreatic intraductal papillary mucinous neoplasm : an ultrashort versus long protocol

Purpose To evaluate whether an ultrashort-protocol (USP) MRI including only T2-weighted HASTE axial and 3D MRCP SPACE sequences adequately measures the largest diameter of the largest cyst and the main pancreatic duct (MPD) and identifies worrisome features (WF) and high-risk stigmata (HRS) when compared to longer protocols (LP, long protocol; SP, short protocol; S-LP, short or long protocol). We also calculated reductions in costs associated with USP. Methods This retrospective study included 183 IPMN patients. Two radiologists compared two imaging sets (USP versus S-LP) per patient, comparing the mean values of the largest cyst and MPD and agreement regarding the presence or absence of cystic or MPD mural nodules and solid pancreatic tumors. The interobserver agreement for cystic mural nodules and WF/HRS was evaluated, using the Bland-Altman plot and Cohen's Kappa. Results A total of 112 IPMN patients were evaluated. For detecting cysts or MPD nodules, WF/HRS, and solid pancreatic tumors, USP and S-LP coincided in 94.9%, 99.1%, 92.4%, and 99.1% of cases, respectively. Both USP and S-LP identified all true cystic mural nodules. The mean size of the largest cyst and MPD was 19.48/19.67 mm and 3.24/3.33 mm using USP versus S-LP, while the mean differences for USP versus S-LP were 0.19 mm and 0.08 mm. The USP cost was 39% of LP cost and 77% of SP. Interobserver agreement was moderate to strong. Conclusions For IPMN surveillance, an ultrashort-protocol MRI provides nearly identical information to the more expensive longer protocols. ; Peer reviewed