Prospective pilot study of functional assessment of the Sphincter of Oddi via cine-dynamic MRCP with selective inversion recovery pulse

Background Sphincter of Oddi dysfunction (SOD) can cause unexplained biliary pain and idiopathic pancreatitis. Although Rome IV criteria recommend sphincter of Oddi manometry (SOM) for diagnosis, SOM is invasive and carries pancreatitis risk. We hypothesized that cine-dynamic magnetic resonance cholangiopancreatography (MRCP) could non-invasively visualize bile and pancreatic juice flow, enabling functional papillary assessment. Methods In this prospective observational study, 40 participants were enrolled, and 29 were included in the final analysis after excluding 11 participants who did not meet the Rome IV criteria (10 healthy controls, 7 with suspected biliary-type SOD [BSOD], and 12 with suspected pancreatic-type SOD [PSOD]). Cine-dynamic MRCP was performed with 20 sequential frames over 5 min. Two quantitative indices were assessed: flow frequency and secretion grade (distance traveled by bile or pancreatic juice). Results Bile flow frequency and secretion grade were significantly lower in both BSOD and PSOD than in controls: frequency (median [range], 13.5 [6–19] in controls vs. 2.0 [1–17] in BSOD, p = 0.006; vs. 8.0 [3–14] in PSOD, p = 0.008) and secretion grade (1.6 [0.3–2.05] in controls vs. 0.2 [0.1–1.3] in BSOD, p = 0.001; vs. 0.5 [0.15–1.75] in PSOD, p = 0.03). Pancreatic juice flow showed no significant difference between BSOD and controls but was significantly reduced in PSOD: frequency (16 [14–19] in controls vs. 9.5 [4–17] in PSOD, p < 0.001) and secretion grade (2.15 [0.7–3.25] in controls vs. 0.98 [0.25–2.9] in PSOD, p = 0.003). Cine-dynamic MRCP parameters improved after sphincterotomy in six patients. Conclusions Cine-dynamic MRCP enables non-invasive visualization and quantification of bile and pancreatic juice flow, providing functional assessment of the sphincter of Oddi.