MR cholangiography

Lionel Arrivé Hôpital Saint Antoine Paris

Hanoi nov 7th 2015

MRCP

� FSE sequences are very heavily T2-weighted

� High signal intensity from static fluid � Classical MRCP included 2D sequences � Modern MRCP should include 3D

sequences which improve both spatial resolution and contrast/noise ratio

2D versus 3D 2D 3D

S/N ratio improves with number of source images

TA 2D = TR x Nex x Ny TA 3D = TA 2D x Nz

Advantages Limitations

•  Near isotropic voxel •  High resolution (1x1x1mm) •  Multiplanar reconstructions

•  Excellent signal/noise ratio

•  Time of acquisition

•  Regular breathing

•  Source images analysis

•  Multiplanar reconstructions

3D Sequence

2D Sequences

Still useful ?

•  Poor quality of 3D sequences •  When one is in a true rush ! •  For dynamic analysis

Bowel signal suppression

•  Paramagnetic contrast (diluted gadolinium) ou superparamagnetic contrast media

•  Blueberry juice •  Black tea •  Pineapple juice (high concentration of

manganese)

Complementary sequences

•  At least a 3D fat-supressed T1-weighted MR sequence for detection of biliary stones

•  A T2-weighted MR sequence : FSE, SSFSE, or diffusion-weighted at B0

•  Gadolinium injection is only optional

Systematic analysis technique

•  3D MRCP : biliary ducts analysis •  T2-weighted MR sequence : liver

heterogeneity and dysmorphia •  T1-weighted MR sequence : biliary stones •  After gadolinium injection : heterogeneity of

contrast enhancement, biliary ducts enhancement, focal hepatic lesion

Systematic analysis technique

•  Biliary ducts analysis : moderate or severe (75%) stenosis, short (2 mm) or long (10 mm), localized (25%) or diffuse

•  Biliary ducts dilatation and biliary stones •  Liver heterogeneity and dysmorphia •  Liver and biliary duct enhancement

Systematic analysis technique

•  Biliary ducts analysis : moderate or severe (75%) STENOSIS, short (2 mm) or long (10 mm), localized (25%) or diffuse

•  Biliary duct DILATATION and biliary stones •  Liver heterogeneity and dysmorphia •  Liver and biliary duct enhancement

Biliary MR Imaging

Multiples traps ! BUT

90% of pitfalls are related to

- Overuse of the term «biliary ducts irregularities» - Overinterpretation of hepatic artery mark

Biliary MR Imaging

Multiples traps ! BUT

90% of pitfalls are related to

- Overuse of the term «biliary ducts irregularities» - Overinterpretation of hepatic artery mark

MRCP : other traps

•  MR system performances (3D MRCP) •  Patient information : Regular breathing •  Learning curve : inter-observer variability •  Numerous other traps

MRCP : other traps

•  MR system performances (3D MRCP) •  Patient information : Regular breathing •  Learning curve : inter-observer variability •  Numerous other traps: BILIARY CONTENT

Biliary MR Imaging

Multiples traps ! BUT

90% of pitfalls are related to

- Overuse of the term «biliary ducts irregularities» - Overinterpretation of hepatic artery mark

Biliary MR Imaging

Multiples traps ! BUT

90% of pitfalls are related to

- Overuse of the term «biliary ducts irregularities» - Overinterpretation of hepatic artery mark

Systematic analysis technique

•  Biliary ducts analysis : moderate or severe (75%) STENOSIS, short (2 mm) or long (10 mm), localized (25%) or diffuse

•  Biliary duct DILATATION and biliary stones •  Liver heterogeneity and dysmorphia •  Liver and biliary duct enhancement

Conclusion

•  3D MRCP with analysis of source images and multiplanar and volume reconstruction

•  Don’t forget Fat-sat 3D T1-weighted MR sequence •  There is a significant learning curve and analysis should

use a systematic technique •  There is a lot of traps and pitfalls but 90% are related to

misuse of the term « irregularities of biliary ducts » and to misinterpretation of hepatic artery mark