MRCP: technique and interpretation

“10 rules in MRCP” Lieven Van Hoe MD PhD OLV Hospital Group Aalst - Belgium

[email protected] 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 SI

TE 60

SI

TE 300-400

cyst ++ / +++ as bright as CSF hemangioma solid + / ++ ± / + not as bright as CSF ± isointense

solid

60 msec

hemangioma

360 msec

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 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 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 level

Extensive 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, 2003 10hr:12min:15sec May 13, 2003 10hr: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 2cm 5cm 3cm

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

axial T2 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 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 (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 artifact

air 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