Transcript 10 rules in MRCP
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