MR of Pancreaticobiliary Diseases in Children

Transcription

1 SPR Body Imaging Course Sept 2015 MR of Pancreaticobiliary Diseases in Children Sudha A. Anupindi MD The Children s Hospital of Philadelphia (CHOP) University of Pennsylvania Perelman School of Medicine

2 Disclosures None Dr. Nancy Chauvin Dr. David Biko Dr. Asef Khwaja ACKNOWLEDGEMENTS

3 Objectives Techniques for Magnetic Resonance Cholangiopancreatography (MRCP) Use of different contrast agents to enhance imaging Technique for MRI of the pancreas ->masses Bile duct pathology Choledochal cyst Alagille syndrome Congenital Hepatic Fibrosis(CHF) Primary sclerosing cholangitis (PSC) Pancreas pathology Pancreatitis congenital anomalies masses

4 MRCP After US, useful adjunct tool to evaluate the bile ducts and pancreatic duct Good diagnostic accuracy in adults and children Advantages: Non-invasive and lacks ionizing radiation Advantage over ERCP and percutaneous cholangiography Disadvantages Cannot provide therapy

5 MRCP Technique* Heavily T2W sequences; TE > 500msec (MR hydrography) 2D and 3D imaging SSFSE (HASTE) 2D T2 Cor oblique 2D Thick slab T2 ( can be done radially) 3D thin slice FRFSE seq- enable reformations in any plane and direction *Egbert et al MRI Clinics NA 2013

6 MRCP Technique 2D Disadvantages Poor spatial resolution Low SNR Inability to reconstruct into multiple planes **No difference in visibility of major bile ducts between 3D FSE and 2D SSFSE radial slab Radial imaging showed superior visualization of the PD *3D Advantages Higher SNR and CNR Improved spatial resolution Thin section isotropic images Create multi-planar reformations *Egbert ND et al MRI Clinics of North America 2013 MRI of the Pediatric Pancreaticobiliary system **Chavhan GB et al Ped Rad 2013

7 Optimizing MRCP Use of parallel imaging decrease scan time Improve duct visibility (Lee JH et al JMRI 2014) Breath hold/ respiratory triggering/navigation 3T versus 1.5T High quality diagnostic studies (Chavhan et al Radiographics 2009, Merkle Em et al Eur J Rad 2006) Higher SNR More artifacts (Almehdar A & Chavhan GB et al B J Radiology 2013)

8 MRCP/MRI pancreas protocol Institutional protocol 3D T2 SPACE Coronal T2 TSE Coronal thick slab T2 High resolution BLADE FSE Axial T2 HASTE FS Coronal (oblique) (long TE) +/- 25 T2 HASTE FS AXIAL (long TE) T1 in and out of phase DWI + IV Contrast protocol Axial T1 VIBE fs Axial Dynamic post-contrast T1 VIBE fs (3 phases) Optional: Coronal delayed post T1

9 MRCP Technique Contrast options Oral IV gadolinium Hepatocyte-specific agent Gadoxetate disodium (Eovist/Primovist) Secretin IV Secretin

10 MRCP Technique Oral contrast T2 bright fluid in bowel can limit duct evaluation Acai/ blueberry/pineapple juice nulls T2 bowel signal* Manganese results in T2 shortening on heavily T2W sequences Given min prior Contraindications: Allergy, Diabetes I, sedation/anesthesia *Bittman ME, MJ Callahan; Ped Rad 2014

11 MRCP Technique IV contrast (conventional gadolinium agents) Role of IV contrast* (routine MRCP is non-contrast) Evaluation of masses Vascular anatomy, preoperative cases Post-operative ( Whipple or pancreatic resections) Dynamic T1 W fat sat are helpful (3-4 runs)** Delayed and PV phase best detecting peripancreatic and periportal LAN & peritoneal mets *Ly JN et al Rad Clinics of NA 2002 **O Neill E et al Rad Clinics of NA 2014

12 MR pancreas- Technique Role of DWI Helpful in evaluation of masses * Solid tumors restrict Simple pancreatic cysts will not restrict Detect pancreatic masses earlier Detect liver and lymph node mets Distinguishing between benign and malignant masses controversial** Both types of tumors restrict *O Neill E et al MRI Clinics NA 2014 **Wang Y et al. Radiographics 2011

13 MRCP Technique-Contrast Role of hepatocyte-specific agent Eovist/Primovist *Delayed T1W images helpful to see excretion into bile ducts (normally excreted min) Evaluation of bile leaks Biliary obstruction Collections in porta hepatis (communicate with bile ducts i.e. biloma) These agents can negatively affect 3D MRCP seq

14 s-mrcp Role of Secretin- Controversial Beneficial - visualize pancreatic duct (PD) Trout AT et al. found effects of secretin on PD dilatation suspect (small change in duct diameter and lack of improvement in visibility of PD)* Gwal et al. report normative PD sizes in children < 11yrs (all MRCP s w/out secretin) * Select Cases Chronic pancreatitis, trauma, congenital abn Assess exocrine response of pancreas Quantitatively or qualitatively (fluid filling in duodenum and small bowel after secretin) Suboptimal, mild, moderate *Trout AT et al Ped Rad 2012 * Gwal K et al Ped Rad 2015

15 MRCP Technique-Contrast Technique s-mrcp 0.2 mg/kg IV slow infusion up to 16 mg Thick slab SS T2 FSE Q30 secs over 5 mins 10 yr-old with cystic fibrosis

16 Pancreatic Pathology Pancreatitis Congenital anomalies Masses

17 Acute pancreatitis (AP) Abdominal pain Terminology Serum amylase and lipase > 3 times normal Imaging findings of AP complete structural + functional restitution Acute Recurrent Pancreatitis (ARP) More than 2 episodes of AP with intervening return to baseline (asymptomatic and normal labs) Chronic pancreatitis (CP) Chronic atypical abd pain Structural changes in the pancreas and pancreatic duct on imaging Plus exocrine and/or endocrine insufficiency

18 Etiology for Pancreatitis in Children Acute pancreatitis Biliary disorders Systemic conditions Medications Trauma Idiopathic Acute Recurrent Idiopathic Structural anomalies Genetic, hereditary Chronic Cystic fibrosis Fibrosing pancreatitis Hereditary chronic pancreatitis Inborn errors of metabolism *Benifla M (2003) J Clin Gastroenterol *Bai HX (2011) JPGN *Joergensen M(2010) Dig Dis Sci *Minen F (2012) Scand J Gastroenterol

19 Identify an etiology Pancreatitis Role of MRCP Stone disease Structural congenital duct variants Complications, progression of disease Guide IR or surgical treatment

20 Pancreas Divisum (PDV) Most common congenital anomaly failure of fusion of the ventral and dorsal anlage 12-26% of patients with recurrent pancreatitis have PDV Main dorsal duct is in continuity with the duct of Santorini and drains minor papilla Ventral duct (not communicating with dorsal duct) joins CBD drains major papilla

21 Accuracy of MRCP in Pancreas Divisum detection is 100% ( c/w ERCP)* Variations in anatomy Clinical relevance remains controversial** Most pts are asymptomatic *Bret P et al Radiology 1996 **Yu J et al AJR 2006

22 Pancreas Divisum Adolescent with normal anatomy of CBD and PD 15 year old with ARP and Pancreas divisum PD CBD

23 Anomalous Pancreaticobiliary Junction (APBJ) Premature union of the bile & pancreatic duct (PD) outside of the duodenal wall (long common channel) Why does it cause pancreatitis? Reflux of secretions into the PD when bile duct pressure > PD pressure High association with choledochal cysts(chc)* Kim M et al 2002 (n=20); 60% of pts with ChC had APBJ seen at MRCP, on ERCP(80%) *Kim M et al AJR 2002

24 APBJ 3 types Early detection helpful for surgical planning not easily seen on MRCP Suspect in Type 1 ChC Treatment: bile duct resection and biliaryenteric anastomosis Kim M et al 2002 AJR

25 1 year old girl with biliary dilatation on US and elevated pancreatic enzymes (Type 1 ChC, long channel & stone)

26 Complications of Pancreatitis Hemorrhage Necrosis Role of MR/MRCP Vascular: splenic vein thrombosis, pseudoaneurysms Pseudocyst formation

27 Hemorrhagic pancreatitis 12 yr old with B-cell ALL T2 with fat sat T2 with fat sat T1 fat sat vibe pre

28 7 yr old Necrotizing pancreatitis T2 fat sat T1 post contrast

29 Pancreatic pseudocyst 12 yr old boy

30 Chronic Pancreatitis Role of MR/MRCP Imaging features Tissue loss, atrophy PD dilatation and dilation and visualization of side branches Irregular pancreas contour calcifications

31 14 year old girl with chronic hereditary pancreatitis Pancreatic duct stricture (arrows)

32 Pancreatic tumors Overall small percent of all pediatric tumors One study over 10 yrs-92 pancreatic disorders, n=10 panc tumors (0.1%) Epithelial Non-epithelial Exocrine and Endocrine

33 Pancreatic tumors Epithelial Ductal Origin Rare Acinar origin Pancreaticoblastoma Acinar cell carcinoma Solid pseudopapillary tumor (SPEN) Endocrine Congenital hyperinsulinemic hypoglycemia Insulinoma Non-Epithelial Lymphoma (Burkitt s) Sarcomas Lymphangioma PNET

34 11 year old with weight loss & fatigue

35 11 year old with weight loss & fatigue T1 Early Post Gad T2 Delayed Post Gad

36 SPEN Female predominance (Asian & Blacks) 10% males Low malignant potential Comprised of solid and cystic (bloody components) Fibrous capsule Dark T1 and T2 capsule 95% surgical cure

37 Islet Cell Tumors Most common functional islet cell tumor of pancreas insulinomas and gastrinomas All others not reported in children Multiple islet cell tumors seen in MEN type 1 Von Hippel-Lindau phacomatoses Gastrinomas seen in Zollinger-Ellison syndrome

38 Imaging Insulinoma Small hypervascular Majority in the body and tail of pancreas US is usually normal CT and MRI hypervascular MRI- Iso-low SI on T1, bright on T2, hypervascular MRI better for liver mets

39 Insulinoma on MRI and PET

40 Biliary Pathology Choledochal Cyst Alagille Syndrome Congenital Hepatic Fibrosis Primary Sclerosing Cholangitis (PSC)

41 Choledochal Cysts Not true cysts, ductal ectasia Jaundice, RUQ pain, palpable mass 80% dx in childhood 20% dx in adulthood MRI provides Extent of cyst into the liver Assoc duct dilatation Compression on adj structures Type 4 Result in pancreatitis APBJ /external compression Todani Classification I: involves CBD, saccular, diffuse or focal (80-90%) II: diverticulum of CBD III: choledochocele IVa & IVb: +intra & extrahepatic dilatation; +extrahepatic saccular

42 9 month old Type 1 Choledochal Cyst

43 Better anatomical detail on MIP from SPACE (left), compared to thick slab (right) GB CC GB CC Coronal MIP from SPACE sequence. Coronal thick slab image. GB: Gallbladder CC: Choledochal cyst

44 Choledochocele Type 3

45 Type 4a Choledochal Cyst causing mass effect on PD pancreatitis CC PD

46 Choledochal Cyst Type V Todani equates this with Caroli disease Purists disagree Caroli disease pure intrahepatic ductal ectasia without any hepatic abn Caroli Syndrome: CHF and Caroli s disease occur together

47 12 year old girl with Caroli s (type V) Dilated CBD Axial HASTE image Arrow: dilated intra-hepatic biliary ducts Axial HASTE image HASTE images reveal dilated intra and extra-hepatic biliary ducts. Liver is normal

48 Alagille Syndrome Role of MRI Portal Hypertension Screen for masses Risk for Hepatocellular ca Recognize large regenerative nodules

49 Congenital Hepatic Fibrosis MR/MRCP ARPKD (nephromegaly with cysts) Portal HTN

50 Congenital Hepatic Fibrosis MR/MRCP Ductal ectasia to varying degrees Choledochal cysts, Caroli syndrome

51 5 year old girl with known congenital hepatic fibrosis- stricture of CBD GB S Coronal HASTE image reveals abrupt tapering of dilated CBD (arrow), consistent with stricture. Also seen is splenomegaly (S)

52 Primary Sclerosing Cholangitis Role of MRI Strictures and dilated ducts beaded appearance Risk for malignancy MRCP 100% specificity, PPD; accuracy 85% * MRCP Classification system based on severity** Pitfall of MRCP Overestimate the degree of stricture Coronal 3D MIP with SPACE at 3T *Ferrara C et al Ped Rad 2002 **Majoie CB et al AJR 1991 Vitellas KM AJR 2002

53 12 yr old UC, PSC with Cholangiocarcinoma

54 Conclusion MRCP is an excellent adjunct to US Optimal imaging can be performed at 3T with 2D & 3D seq with BH or respiratory triggered/navigator gated Several contrast options- enhance Focused role MR in the evaluation of common pancreatic and biliary pathology

55 Thank You!