Hepatic and Pancreaticobiliary Mri and MR Cholangiopancreatography With and Without Secretin Stimulation in Normal Cats

Abstract

Magnetic resonance (MR) cholangiopancreatography is useful in humans to diagnose biliary and pancreatic diseases. Some of these protocols incorporate the use of secretin, which stimulates the exocrine pancreas to release bicarbonate with secondary dilation of the pancreatic duct. We compared the utility and quality of multiple hepatic-pancreaticobiliary MR imaging sequences before and after secretin stimulation of the pancreatic duct in five healthy cats. Multiple MR sequences were evaluated, including fast Spoiled Gradient Recalled in- and out-of-phase, Single Shot Fast Spin Echo (SSFSE), T2 Fast Spin Echo, MR cholangiopancreatography (pre- and postsecretin administration), and Fast Acquisition with Multiphase Efgre (FAME) (postsecretin and before and after gadolinium administration). The MR cholangiopancreatography protocol with secretin stimulation was feasible and yielded high-contrast maps of the biliary ductal anatomy but the pancreactic duct was seen inconsistently. The FAME series most consistently provided visualization of biliary and postsecretin pancreatic ductal anatomy, combined with very good depiction of the liver and pancreas. The remaining sequences each had satisfactory utility and diagnostic quality, with the exception of the SSFSE sequences. Secretin improved the conspicuity of the pancreatic duct.

Magnetic resonance (MR) imaging and MR cholangiopancreatography findings in cats with cholangitis and pancreatitis

“…25,26,37,38 All cats in this study had more pronounced dilation of the pancreatic duct post-secretin stimulation compared with previously studied normal cats. 25,26 It has been suggested that mild dilation post-secretin could indicate retention of ductal elasticity. 37 In contrast, the two cats with pancreatic cysts and the most severe pancreatic duct dilation did not respond to secretin stimulation, suggesting minimal duct elasticity.…”

“…Two of five normal cats had gall bladder debris which had similar imaging characteristics. 26 Nine of 10 cats had a mildly thickened and moderately enhancing gall bladder wall [mean 2.2 mm ± 0.3 mm (median 1.9 mm)] (Figure 5b). In normal cats, the gall bladder wall was mildly contrast enhancing and was difficult to measure with electronic calipers owing to its small size, which required magnifying the image until pixelated [1.7 mm-0.5 mm (median 1.2 mm)].…”

“…In normal cats, the gall bladder wall was mildly contrast enhancing and was difficult to measure with electronic calipers owing to its small size, which required magnifying the image until pixelated [1.7 mm-0.5 mm (median 1.2 mm)]. 26 The common bile duct was normal in 8/10 cats and too small for measurement with electronic calipers. In two cats the common bile duct was dilated and tortuous measuring 4.4 mm and 5.6 mm.…”

“…Both imaging procedures included the use of secretin (ChiRhoStim; ChiRhoClin, established feline dose of 2 U/kg IV) to evaluate its effects on pancreatic duct dilation. 25,26 The first three enrolled cats of the project received the secretin during the initial ultrasound study and also a second secretin injection during MRI/MRCP the next day.…”

“…26 Feline MRI/MRCP provided high quality images of the liver, biliary ductal system, pancreas, and pancreatic duct. Visualization of the small normal feline pancreatic duct was feasible, although its conspicuity was further improved with secretin stimulation.…”