sign in sign up
<<
Home , Secretin

SECRETIN ENHANCED MRCP Andrew T. Trout, MD

@AndrewTroutMD Relevant Disclosures • Grant support: – National Foundation • In-kind grant support: – ChiRhoClin, Inc. Objectives • Review basics of and its role in diagnosis of pediatric pancreatic disease • Describe techniques for performing and interpreting secretin-enhanced MRCP Pediatric Pancreatic Disease • Endocrine insufficiency • Exocrine insufficiency • Pancreatitis Pediatric Pancreatic Disease • Endocrine insufficiency • Exocrine insufficiency • Pancreatitis Pediatric Pancreatic Disease • Multiple hereditary causes of exocrine insufficiency • Increasing recognition of acute recurrent (ARP) and (CP) as causes of exocrine insufficiency – 1-5 per 100,000 • Increasing recognition of genetic causes of ARP and CP Secretin • Secretin plays a role in assessment of pediatric pancreatic disease – Increase duct visibility – Duct stress test – Assess exocrine fxn – Perfusion effect?

Manfredi R, et al. Radiology. 2002 Sep;224(3):675-82. nature.com Secretin Basics

• In broad terms: Adds value only* for pancreatic imaging • Synthetic human secretin – 0.2 µg / kg, max 16 µg – Test dose (atopy, asthma) – Slow injection over 1 minute (abd pain, ) – Contraindications – acute pancreatitis, allergy • Mechanisms: – secretion – Transient increase in tone at the sphincter of Oddi • Plasma half-life = 3-5 min – Duration of effect >10 min • Cost = up to $2000/vial

Afroze S, et al. Ann Transl Med. 2013 Oct;1(3):29. Secretin Basics

• In broad terms: Adds value only* for pancreatic imaging • Synthetic human secretin – 27 polypeptide – 0.2 µg / kg, max 16 µg – Test dose (atopy, asthma) – Slow injection over 1 minute (abd pain, vomiting) – Contraindications – acute pancreatitis, allergy • Mechanisms: – Bicarbonate secretion – Transient increase in tone at the sphincter of Oddi • Plasma half-life = 3-5 min – Duration of effect >10 min

Matsufuji H, et al. J Pediatr Surg. 2006 Oct;41(10):1652-6. Adjuncts to secretin • Negative enteric contrast – Forms • Superparamagnetic iron oxide (ferumoxsil) without • Juice – pineapple, blueberry, acai – Not all created equal – May help duct visibility / image quality

– ? Confounding for exocrine function with blueberry assessment?

Bittman ME, Callahan MJ. Pediatr Radiol. 2014 Jul;44(7):883-7. Adjuncts to secretin • Negative enteric contrast – Forms • Superparamagnetic iron oxide (ferumoxsil) without • Juice – pineapple, blueberry, acai – Not all created equal – May help duct visibility / image quality

– ? Confounding for exocrine function with blueberry assessment? “In this study, we made the assumption that once the pancreatic fluid reached the its signal was not dramatically suppressed by the negative oral contrast agent.” – Matos. 1997

Bittman ME, Callahan MJ. Pediatr Radiol. 2014 Jul;44(7):883-7. Basic Imaging Sequences • Duct assessment – 3D MRCP • Resp triggered, BH, Navigator – Thick slab MRCP • Angled to duct • Exocrine function – BH fat sat T2 (SSFSE) Pure Pediatric Data • All related to duct assessment • Arcement et al. Ped Rad. 2001 (n = 3) – Subjective improvement in duct visibility • Manfredi et al. Radiology. 2002 (n = 16) – Improved sensitivity for findings of chronic pancreatitis (but more false pos) – Duct dilation ~1 mm • Delaney et al. Ped Rad. 2008 (n = 41) – Subjective improvement in duct visibility – Duct dilation ~0.5 mm • Trout et al. Ped Rad. 2013 (n = 20) – No improvement in duct visibility – Duct dilation ~0.3 mm Arcement CM, et al. Pediatr Radiol. 2001 Feb;31(2):92-7. Manfredi R, et al. Radiology. 2002 Sep;224(3):675-82. Delaney L, et al. Pediatr Radiol. 2008 Jan;38(1):64-75. Trout AT, et al. Pediatr Radiol. 2013 Apr;43(4):479-86. Duct visibility • Secretin likely improves visibility of the duct – May add value in detecting occult anatomic abnormalities – Caveats: • Most published data confounded (non-blinded) • Diseased ducts are generally visible w/o secretin Assessment of Exocrine Function • Qualitative • Quantitative Gr 0 Assessment of Exocrine Fxn • Qualitative Gr 1 – Dynamic thick slab imaging or serial static images Gr 2 –Matos grading • Grade 0 – no secretion • Grade 1 – filling of bulb • Grade 2 – filling to genu inferius Gr 3 • Grade 3 – filling beyond genu inferius

Matos C, et al. Radiology. 1997 May;203(2):435-41. emedicine.commodifiedfrom: Assessment of Exocrine Function • Qualitative – Matos not validated in children

pre 1 min 5 min 10 min 15 min Assessment of Exocrine Function • sMRCP graded per Matos correlates with lab-based diagnosis of exocrine insuff (fecal elastase, fecal fat, breath test) – 69% sens, 90% spec • sMRCP graded per Matos correlates with bicarbonate secretion by endoscopic PFTs Gillams A, et al. Pancreatology. 2005 5:100. Schneider AR, et al. 2006 Oct;40(9):851-5. Cappeliez O, et al. Radiology. 2000 May;215(2):358-64. Assessment of Exocrine Function • Qualitative • Quantitative – Total secreted fluid volume • Dual time-point imaging – Flow rate (mL / min) • Multi-time-point imaging Assessment of Exocrine Function • Image segmentation – Pre- and post-secretin imaging parameters should be identical • Fluid pixels – Threshold – Water standard • Fluid area per slice • Σ(area x slice thickness)

pre-secretin post-secretin Assessment of Exocrine Function • Normative data exist for adults – 111.8 ± 49.8 mL at 11.9 ± 2.8 minutes • No normative data for pediatrics – We are working on this

Mensel B, et al. AJR Am J Roentgenol. 2014 Jan;202(1):102-8. Sneak Peak

140

120 Adult mean 100 n = 29 80 Ages 6 - 16 60 Mean – 1SD

Secreted Volume (mL) Secreted Volume 40

20 Mean – 2SD 0 0 min 1 min 5 min 10 min 15 min

Unpublished data Conclusions • Secretin can add value in the assessment of pancreatic disease by MRI • Current roles include: – Improved duct visualization (likely) – Exocrine function assessment • Qualitative vs. Quantitative THANK YOU

@AndrewTroutMD