MRCP technique and interpretation 10 rules in MRCP

MRCP: technique and interpretation “ 10 rules in MRCP” Lieven Van Hoe MD Ph. D OLV Hospital Group Aalst - Belgium lievenvanhoe@hotmail. com www. lievenvanhoe. com

Procedure Axial and coronal double echo HASTE (5 mm) NON-FATSAT TE 60 TE 360

10% of your patients has focal liver lesions Double echo HASTE: lesion characterizarion SI SI TE 60 TE 300 -400 cyst ++ / +++ as bright as CSF hemangioma + / ++ not as bright as CSF solid ± / + ± isointense

solid 360 msec hemangioma

Axial and coronal double echo HASTE (5 mm) • Thin-section MRCP • Scout for breath-hold single-slice MRCP

Procedure Single-slice MRCP – – – RARE sequence slice thickness 3 cm, TE 1100 3 sec / image breath hold = overview images

Procedure Axial non-FATSAT turbo. FLASH T 1 = magic tool for detection of pancreatic cancer and focal liver lesions Liver white Pancreas white Tumor dark

Procedure Multiphase contrast-enhanced VIBE • Problem-solving tool • Pancreatic lesions • Only if required T P

Rule N° 1 Never use MRCP without crosssectional imaging

Man, 43 -year, elevated liver enzymes, previously papillotomy for biliary stone disease. Stone?

Aerobilia Always correlate with axial T 2 weighted images !! Air-fluid level Extensive air may make MRCP nondiagnostic

Liver function abnormalities

Missed pancreatic carcinoma Never perform MRCP without cross-sectional imaging never, never TFLASH: 700 msec/slice – HASTE: 400 msec / slice

Rule N° 2 Use dynamic (repetitive) MRCP

May 13, 2003 10 hr: 12 min: 15 sec May 13, 2003 10 hr: 12 min: 23 sec

Temporal variability in shape of the sphincter of Oddi It works ! Only possible with breath-hold singleslice MRCP

Rule N° 3 Use the correct slice thickness Not 10 cm !

10 cm 2 cm 5 cm 3 cm

Rule N° 5 Be aware of biliary flow phenomena on axial images

axial T 2 Flow void in common bile duct Compare with single-slice MRCP Believe single-slice MRCP if results are different

Rule N° 6 Be aware of the pseudo-calculus sign

Pseudocalculus sign 30 sec later

Rule N° 7 Small stones not surrounded by fluid are invisible

Does the patient has stones in distal CBD ? ? Not included in slice Normal size

Impacted stone May be difficult diagnosis ! No surrounding fluid Repetitive imaging useful

Rule N° 8 Anticipate differences between MRCP and ERCP images

MRCP: - imaging in the physiologic state (no ductal distention) - limitations in spatial resolution • Low-grade stenoses can be missed • The length of stenoses can be overestimated (physiologic collapse) • Small polypoid ductal lesions can be missed

MRCP – ERCP The same things look different !! (distention)

Aberrant right posterior duct

Rule N° 9 For lesion characterization, use all information available (T 1, T 2, MRCP, multiphase contrast-enhanced images)

Cirrhosis. Incidental finding.

The double duct sign can be caused by chronic pancreatitis with pseudomass. Refer to axial T 1 and T 2 -weighted images for differentiation with carcinoma.

Rule N° 10 Be aware of susceptibility artifact

Watanabe et al. Radio. Graphics 1999 19: 415 -429

Susceptibility artifact air metal

Thank you !!

The double duct sign can be caused by chronic pancreatitis with pseudomass. Refer to axial T 1 and T 2 -weighted images for differentiation with carcinoma.

Rule N° 4 Be careful with MIP images

The patient recently underwent laparoscopic gallbladder surgery and now suffers from jaundice. Injury to CBD?

MIP Projects 3 D reality on 2 D image Pathology may be masked