MRCP: technique and interpretation

“10 rules in MRCP”

Lieven Van Hoe MD PhDOLV Hospital Group Aalst -

Belgiumlievenvanhoe@hotmail.com www.lievenvanhoe.com

Procedure Axial and coronal double echo HASTE

(5mm)NON-FATSAT

TE 60 TE 360

10% of your patients has focal liver lesions

Double echo HASTE: lesion characterizarion

SITE 60

SITE 300-400

cyst ++ / +++ as bright as CSF

hemangioma

+ / ++ not as bright as CSF

solid ± / + ± isointense

60 msec 360 msec

solid

hemangioma

Axial and coronal double echo HASTE (5mm)

• 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 turboFLASH T1= magic tool for detection of pancreatic cancer

and focal liver lesions

Liver whitePancreas 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 cross-sectional imaging

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

Aerobilia

Always correlate with axial T2-weighted images !!

Air-fluid levelExtensive air may make MRCP nondiagnostic

Liver function abnormalities

Missed pancreatic carcinoma

Never perform MRCP without cross-sectional imaging

never, never, never

TFLASH: 700 msec/slice – HASTE: 400 msec / slice

Rule N° 2

Use dynamic (repetitive) MRCP

May 13, 200310hr:12min:15sec

May 13, 200310hr:12min:23sec

Temporal variability in shape of the sphincter of Oddi

It works !

Only possible with breath-hold single-slice MRCP

Rule N° 3

Use the correct slice thickness

Not 10 cm !

10cm 5cm

2cm 3cm

Rule N° 5

Be aware of biliary flow phenomena on axial images

Flow void in

common bile duct

Compare with single-slice MRCP

Believe single-slice MRCP if results are different

axial T2

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

Not included in slice

Not included in slice

Does the patient has stones in distal CBD ??

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 – ERCPThe same things look different !!

(distention)

Aberrant right posterior duct

Rule N° 9

For lesion characterization, use all information available (T1, T2,

MRCP, multiphase contrast-enhanced images)

Cirrhosis. Incidental finding.

The double duct sign can be caused by chronic pancreatitis with pseudomass. Refer to axial T1- and T2-weighted images for differentiation with carcinoma.

Rule N° 10

Be aware of susceptibility artifact

Watanabe et al. RadioGraphics 1999 19: 415-429

Susceptibility artifactair

metal

Thank you !!

The double duct sign can be caused by chronic pancreatitis with pseudomass. Refer to axial T1- and T2-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 3D reality on 2D image

Pathology may be masked