Transcript Liver MRI PowerPoint Presentation

Dr. Fung
OHSU Body Radiology
Patient Preparation
• Education
• Approximate duration of the exam
• Breath-holding
Stress importance
• Expiration
• If cannot sustain BH, slowly inhale over time
• Practice with patient
•
• Describe sensations of Gd infusion
• 2L NC O2
• No O2 if patient has
COPD/emphysema: ASK!
•Patient Position
• Supine
• Feet first
• Cushion under knees to relieve back
pressure
• Arms at sides
• Coil Position
• 3 fingers below xyphoid
process
• Ensure parallel positioning
• Other
• Ear plugs
• Emergency button
• Anxiolytic
• Music
3-Plane Localizer
• Ensure coil is placed properly
for optimized liver imaging.
• Run calibration (reference)
sequence for ASSET/SENSE.
•2 with BH Exp, 2 Free Breath
• If patient moves or coil
position is changed, rerun
calibration scan.
• Clinical
• Quick eval of spine
Ax/Cor Single Shot TSE
• Coronal SSFSE/SSTSE T2
• FOV <48 cm
• SLT/gap: 8 mm/0
• ASSET/SENSE: none
• BH (Arms Up if Possible)
• Axial SSFSE/SSTSE T2
• FOV <34 cm
• SLT/gap: 8 mm/0
• ASSET/SENSE: none
• BH
• Liver through kidneys
• Two acquisitions if necessary
Overlap acquisitions
• NO INTERLEAVE
•
•Clinical
• Overview of anatomy
• Fluid-filled structures
• Liver size
Coronal 3D FIESTA/B-TFE
• Parameters
• FOV: 38 cm
• SLT/gap: 3-4 mm/reconstructed
to 1-2 mm
• ASSET/SENSE: min
• BH
• Liver through pancreas
• Arms Up if possible- Fold over
• Clinical
• Poor man’s MRCP
• Decreases dephasing in patients
with significant ascites
Axial 2D FIESTA/B-FFE
• Parameters
• FOV: <34 cm
• SLT/gap: 5 mm
• ASSET/SENSE: min
• BH: (resp-trig uncooperative
patient)
• Liver through bottom of kidneys
• Clinical
• Vascular patency: important if
unable to adequately BH during
post-Gd sequences
Axial Dual Echo SPGR (In/Out Phase)
•
Parameters
•
•
•
•
•
FOV: <34 cm
SLT/gap: 7 mm/1
ASSET/SENSE: none
BH
Two acquisitions if necessary
•
•
Overlap acquisitions
NO INTERLEAVE
•
Repeat as necessary to optimize image
quality
• Run 3D Dixon on MR1 for In/Out Phase
imaging
•
Clinical
•
•
•
Detect lipid and iron
Evaluate kidneys
T1 appearance of lesions
Axial Resp-Trig FSE T2 Fat Sat
• Parameters
• FOV: <34 cm
• SLT/gap: 7 mm/1
• ASSET/SENSE: None
• Respiratory Triggered
• Liver through bottom of
kidneys
• Position gating trigger on
dome of diaphragm half in
lung field/half in liver
• Clinical
• Increased lesion conspicuity
• T2 characteristics
• Lymphadenopathy
•
Axial 3D LAVA/THRIVE/DIXON
Parameters
•
•
•
•
•
•
FOV <34 cm
SLT/gap: 4-5 mm/reconstructed to 2 mm
ASSET/SENSE: 1.5, max
BH
Liver through bottom of kidneys
Breath-holding
•
•
•
Expiration
Practice breathing with patient
Watch respiratory graph so breathing cycle
not interrupted
• Stress importance of these images
• If can’t hold breath long enough, slowly and
steadily inhale (as had practiced before the
exam)
•
Precontrast
•
Ensure :
•
•
•
•
Adequate coverage
Adequate fat suppression
Patient understands BH
No artifacts through liver
Axial 3D Dynamic Timing
•
Post-Contrast
•
Arterial: 25s after start of injection – MOST INPORTANT SCAN
•
•
•
•
prior to scanning this sequence, please remind patient of the importance of this
sequence
Arterial Phase is for Hepatic Artery uptake, NOT early arterial (30sec k0 time)
This time depends on k0 time, injection rate, cardiac output, hemodynamics
We may be switching back to bolus tracking because of these variables.
• Portal: 60s after start of injection
• Late Portal: 100s after start of injection
• Equilibrium: 180s after start of injection
• 10-min Delay (FSPGR)
• Please send images to PACS in proper fashion (Philips)!
•
Clinical
•
Lesion detection and characterization
Axial 3D DIXON (Water Images)
• Parameters
• FOV <34 cm
• SLT/gap: 4-5 mm/reconstructed to 2 mm
• BH
• Liver through bottom of kidneys
• Breath-holding
• Faster scan and better fat sat than THRIVE
• ONLY available on MR1 Philips
• 3D Dixon will also replace In/Out Phase on MR-1
• Ensure :
•
•
•
•
Adequate coverage
Adequate fat suppression
Patient understands BH
No artifacts through liver
10min Delay Axial FSPGR Fat Sat
• Parameters
• FOV <34 cm
• SLT/gap: 7 mm/1
• ASSET/SENSE: None
• BH
• Liver through Aortic Bifurcation
• Two acquisitions if necessary
•
•
•
Overlap acquisitions
NO INTERLEAVE
Repeat as necessary to optimize
image quality
• Clinical
• Evaluate for delayed contrast
enhancement
Additional Optional Sequences
• DWI
• Parameters: as specified on the Philips Scanner
• Through the liver
• Please be sure to perform ADC map
• Clinical: Lesion detection, esp. for metastatic lesions to
liver
• EOVIST Protocol
• Axial Post-contrast LAVA/THRIVE at 5 min’s and 20 min’s
• Axial and coronal Pre- and Post-contrast “STEALTH” as
required by the radiologist oncologists
• Clinical: Lesion detection
MRCP
 To be performed after contrast sequences
 Default is MRCP + liver mass protocol
 Rad will specify if study to be done without contrast
 MRCP 3D Axial
 FOV: <34 cm
 SLT/gap: 1.4 mm/0
 ASSET/SENSE: minimum
 Respiratory Triggered
 Through bottom 2/3 of liver, including pancreas
 Parameters:





MRCP Thin Slice
FOV: 32 cm
SLT/gap: 4-5 mm/0
Slices: 15, each
ASSET/SENSE: None
BH
Coronal
RAO
LAO
•
Off Axial image, select image showing CBD through pancreatic head
• Coronal
•
•
•
Image posterior to CBD as it passes through the pancreatic head to anterior to the porta
hepatis
Whole gallbladder should be included although can be sacrificed to image whole CBD
RAO Coronal Oblique
•

•
•
Rotate 20-30⁰ counterclockwise
Include CBD
Gallbladder not necessarily included
LAO Coronal Oblique
•
•
•
Rotate 20-30⁰ clockwise from straight coronal
Center on CBD
Entire gallbladder included
MRCP Thick Slab, Radial
 Parameters:





FOV: 32 cm
SLT/gap: 40 mm/0
Slices: 12
ASSET/SENSE: None
BH
RADIAL
• Off Axial image, select image showing Pancreatic Duct
(Pancreatic Head)
• Multiple slabs off different angles (15-30⁰ intervals)
• Adequate pause to eliminate crosstalk