5.2Benign Nontraumatic Abnormalities

!

!

a

c

Fig. 125. a–c Three projective images out of a series of 20 showing a small hypointense “lesion” in the distal common bile duct (arrows). The unchanged shape of the abnormality during dynamic scanning virtually rules out a pseudocalculus phenomenon. In this case, the lesion represented a small stone. d, e Two consecutively obtained projective images in a different patient.d Image obtained during contraction of the sphincter showing no abnormalities (arrow). Note absence of fluid in the adjacent duodenum. e Relatively large stone impacted in the distalmost portion of the extrahepatic bile duct (arrow). This stone is invisible in a because it is not surrounded by fluid.Note that

the pseudocalculus sign appears during contraction, and not during relaxation (see # 122)

b

d

e

#126 Choledochocele

Related topics: #30 (Caroli’s disease), #68 (choledochal cysts)

KEY FACTS: DISEASE

●Cystic dilation of the distal/intramural portion of the common bile duct with herniation of the common bile duct into the duodenum (similar to ureterocele)

●Represents type III bile duct cyst (see #30)

●Often manifests in adulthood

●Etiology:

–Congenital: diverticulum of the distal common bile duct; stenosis of the ductal orifice

–Acquired: stone passage Æ inflammation Æ stenosis of the orifice

●Symptoms: nausea, vomiting, episodic abdominal pain

●Stones/sludge often present

KEY FACTS: MRI (FIG. 126)

●Typical appearance:

–Rather than being narrowed, the intramural portion of the common bile duct is broadened and clubbed

–The papilla bulges into the duodenum

References

De Backer AI, Van den Abbeele K, De Schepper AM et al. (2000) Choledochocele: diagnosis by magnetic resonance imaging. Abdom Imaging 25 : 508–510

Venu RP, Geenen JE, Hogan WJ (1984) Role of ERCP in the diagnosis and treatment of choledochocele. Gastroenterology 87 : 1144–1149

#127 Sphincter Dysfunction,

General

KEY FACTS: DISEASE

●Clinical entity resulting from the impedance of biliary and/or pancreatic flow

●Most common in middle-aged women

●Underlying disorder:

–Structural narrowing (fibrosis): papillary stenosis

–Motor abnormality: dyskinesia

●Predisposing factors: prior cholecystectomy; stone passage

●Symptoms: biliary colic

●Objective diagnostic criteria (Hogan et al. 1987):

–Elevation of transaminases and alkaline phosphatase (twice the normal value), documented on two different occasions

–Dilation of extrahepatic bile duct (>12 mm)

–Delayed emptying on ERCP (> 45 min)

●Classification:

–Type I: all three criteria fulfilled

–Type II: one or two criteria fulfilled

–Type III: no criteria fulfilled

●Gold standard for diagnosis: manometry. If dyskinesia is present, abnormalities include (Toonly et al. 1997):

–Most common: elevation of basal pressure (> 40 mmHg)

–Increased frequency of phasic wave contractions (more than eight per min)

● Other diagnostic techniques that have been proposed:

– 99mTc-hepato-iminodiacetic acid (HIDA) scan (delayed transit from the common bile duct to the bowel)

–Secretin test with measurement of pancreatic duct diameter (see also # 19)

–Fatty meal test with measurement of bile duct diameter (see also # 19)

●Treatment:

–Type I: sphincterotomy

–Type II: sphincterotomy if manometry is positive

–Type III: medication

●Complications:

–Chronic obstructive pancreatitis (see

# 168)

–Secondary sclerosing cholangitis (see #45; Tarnasky et al. 1997)

References

Hogan WJ, Geenen JE, Dodds WJ (1987) Dysmotility disturbances of the biliary tract: classification, diagnosis, and treatment. Semin Liver Dis 7 : 302–311

Tarnasky PR, Hoffman B, Aabakken L et al. (1997) Sphincter of Oddi dysfunction is associated with chronic pancreatitis. Am J Gastroenterol 92 : 1125–1129

Toonly J, Roberts-Thomson IC, Dent J, Lee J (1985) Manometric studies in patients with suspected sphincter of Oddi dysfunction. Gastroenterology 88 : 1243–1250

#128 Sphincter Dysfunction,

Features on Dynamic MRCP

Related topic: # 120 (vaterian sphincter complex: normal contractile activity)

KEY FACTS

!● The following morphologic patterns may be seen on dynamic MRCP:

–“Type A”: nonvisualization of sphincter segment (Fig. 128a, c–e)

–“Type B”: absence of variability in shape on serial breathhold images (Fig. 128b, f–j)

●These morphologic abnormalities of the vaterian sphincter complex may be associated with dilation of the common bile duct and pancreatic duct (not always present)

●Note: Detection of these abnormalities requires use of a dedicated MR technique and specific attention to the morphology of the vaterian sphincter complex on consecutive images

References

Van Hoe L, Vanbeckevoort D, Gryspeerdt S et al. (1997) MR cholangiography of periampullary lesions: potential pitfalls in diagnosis. Radiology 205 (P) : 709

#129 Sphincter Dysfunction, False-Negative Diagnosis on Dynamic MRCP

KEY FACTS: MRI

●While dynamic MRCP provides information on the presence of contractile activity, it does not actually show the passage of bile into the duodenum

●In some patients with papillary dyskinesia, ERCP shows delayed emptying of the common bile duct despite the presence of contractile activity; this feature is not shown on MRCP (Fig. 129)

●Note: In order to overcome this limitation, the use of provocative tests has been proposed (Mariani et al. 2003).

Further studies are required to determine the role of MRCP in comparison with ERCP/manometry.

References

Mariani A,Curioni S,Zanello A,et al. (2003) Secretin MRCP and endoscopic pancreatic manometry in the evaluation of sphincter of Oddi function: a comparative pilot study in patients with idiopathic recurrent pancreatitis. Gastrointest Endosc 58 : 847–852

Fig. 129 a–d. Projective MR images showing apparently normal contractility of the sphincter: a sphincter relaxation with visualization of the intramural segment; b contraction (arrows). c ERCP image showing apparently normal distal (intramural) portion of bile duct (arrow). d However, 1-h delayed ERCP image shows bile ducts still filled with

contrast medium, thus suggesting sphincter dysfunction (see # 127,diagnostic criteria). Surprisingly, manometry showed normal contractility and normal baseline pressure. The final diagnosis was sphincter dysfunction, however, mainly because the symptoms disappeared after sphincterotomy

#130 Benign Tumors

KEY FACTS: DISEASE

●Histology of ampullary tumors:

–Adenoma most common

–Other types: leiomyoma,neurofibroma, hemangioma, hamartoma

●Incidence: 0.04%–0.62%

●Age peak: 50–70 years

●Associations (adenoma):

–Familial polyposis coli

–Gardner syndrome

●Adenoma is considered a precancerous lesion (Yamaguchi and Enjoji 1991)

KEY FACTS: MRI

●Typical features (Fig. 130a):

–Dilation of pancreatic duct and bile ducts

–Bulging papilla (= generously sized papilla protruding into the lumen) with or without soft tissue mass

●Differential diagnosis (usually impossible by MRI):

–Non-neoplastic causes of bulging papilla: impacted gallstone; choledochocele; papillitis (Fig. 130b)

–Malignant tumors (see # 132, 133)

References

Seifert E, Schulte F, Stolte M (1992) Adenoma and carcinoma of the duodenum and papilla of Vater: a clinicopathologic study. Am J Gastroenterol 87 : 37–42

Yamaguchi K, Enjoji M (1991) Adenoma of the ampulla of Vater: putative precancerous lesion. Gut 32 : 1558–1561

Fig. 130. a Axial T2-weighted image showing enlarged papilla bulging into the duodenal lumen (arrowheads). The final diagnosis was tubulovillous adenoma. b Different patient. Projective image sho-

wing prominent papilla (“bulging papilla”; arrow). In this patient, the final diagnosis was papillary edema, most likely secondary to stone passage

5.3Traumatic, Postoperative, and Iatrogenic Abnormalities

#131 Sequelae/Complications

of ERCP

KEY FACTS: DISEASE

●Complication rate: between 4.6% and 12%, depending on the type of procedure (diagnostic, manometry, sphincterotomy) (Cotton and Chong 1995)

●Complications of diagnostic ERCP:

–Pancreatitis (most common)

–Infection

–Sepsis (0.8%)

–Aspiration pneumonia (0.1%)

●Complications of sphincterotomy (Catalano et al. 1997):

–Overall complication rate: 10%

–Most common: hemorrhage, perforation (0.4%–2.1%), pancreatitis

–Mortality rate: 0.3%

KEY FACTS: MRI

●Pancreatitis (see # 151)

●Perforation:

–Paraduodenal collection containing fluid and/or air

–May spread in retroperitoneum

–A defect may be demonstrated in the wall of the distal common bile duct

●Bleeding:

–Collection with typical signal inten-

sity of blood (see #51)

● Note: After sphincterotomy, the distal- ! most portions of the bile duct and pancreatic duct may have an unusual appearance (Fig. 131):

–Abnormally “broad” aspect

–Absence of normal contractions

–Irregular contours

–Intraluminal air

References

Catalano O, Lapiccirella G, Rotondo A (1997) Papillary injuries and duodenal perforation during endoscopic retrograde sphincterotomy: radiological findings. Clin Rad 52 : 688–691

Cotton P, Chong W (1995) Complications of ERCP and therapy. In: Silvis S, Rohrmann C, Ansel H (eds) Endoscopic retrograde cholangiopancreatography. Igaku-Shoin, New York, pp 446–469