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Cardiac MR SequencesGreg Kicska, MD / PhD
Thoracic Imaging, University of Washington
Cardiac MRI Exam• Axial stack bright-blood static
• Vertical long axis single image bright-blood cine
• Short axis stack black-blood static
• Short axis stack bright-blood cine
• 4-chamber single image bright-blood cine
• Aortic valve single image phase contrast cine
• 4-chamber single image perfusion real-time cine
• Short axis stack late gadolinium enhancement static
Orientation Sequence TimeCoverage
Short axis4-chamber
VLALVOTRHLA
Black bloodBright bloodPhase conPerfusion
LGE
CineStatic
Real Time
StackSingle Img
Sequence Breakdown
Bright-Blood
Balanced contrast = T2/T1Spoiled contrast = 1/T1
Bright-BloodSteady-state sequences
Tissue T2 T1 T2/T1 1/T1
Myo 30 800 40 1.25
Blood 250 1200 200 8.3
Fat 60 250 240 4
Bright-BloodSteady-state sequences
Tissue T2 T1 T2/T1 1/T1
Myo 30 800 40 1.25
Blood 250 1200 200 8.3
Fat 60 250 240 4
Tissue Balanced SpoiledMyo
BloodFat
Bright-BloodPros•Cine (function) •Real time imaging•High S/N (anatomy adjacent to blood pool)•Turbulent artifact (jets)Cons•No direct T1 or T2 characterization for bSSFP•Artifact prone•High SAR
Diastole
Systole
Black-BloodDouble inversion recover spin echo imaging
Black-BloodDouble inversion recover spin echo imaging
T1-W, T2-W or PD
Tissue T2 T1 T2 1/T1
Myo 30 800 12 20
Blood 250 1200 100 30
Fat 60 250 24 100
Black-BloodDouble inversion recover spin echo imaging
Tissue T2 T1 T2 1/T1
Myo 30 800 12 20
Blood 250 1200 100 30
Fat 60 250 24 100
Tissue T2-W T1-WMyo
BloodFat
Black-BloodDouble inversion recover spin echo imaging
Tissue T2-W T1-WMyo
BloodFat
Saturate blood
Black-BloodDouble inversion recover spin echo imaging
Tissue T2-W T1-WMyo
BloodFat
Saturate bloodSaturate fat
Pros• T1-W, T2-W or PD• 1 slice per beat possible• Fat saturation• Artifact resistant
Cons•No cine• Slow flow artifact
Black-Blood
Black-BloodFat saturation - edema / fat differentiation
Fat-Sat
Black-BloodFat saturation - edema fat differentiation
Fat-Sat
Black-BloodFat saturation - mass characterization
Fat-Sat
• Anatomy
• Pericardium
•Mediastinum
•Masses
Late Gd EnhancementT2 Fat-Sat
Black-BloodAnatomy - Pericardium
Late Gadolinium Enhancement
• T1-W image
• Acquired 10-15 min post-Gd
•Myocardium is dark
NORMAL ABNORMAL
Abnormal myocardium bright
• Fibrosis
• Damaged microvasculature
• Expanded interstitial space
Late Gadolinium Enhancement
Late Gadolinium Enhancement
Viable
Non-viable
EdemaBlack Blood T2-W
Damaged MyocardiumLate Gad Enhancement
Late Gadolinium Enhancement
320 ms 550 ms
Phase Contrast
Stoke VolumeForward flowBackward flowRegurgitant fractionPeak Velocity
•Quantitate flow•Regurgitant fraction•Pressure gradient•Quantitate shunt fraction•Visualize low flow jets
Phase Contrast
•Aortic regurgitant fraction?•ASD shunt volume?•PA pressure gradient?•Is low flow shunt present?
Phase Contrast
Cardiac MR Summary
•Orientation and coverage targets anatomy, sequence characterizes tissue, time is for function
• Steady-state shows function and objects in the blood pool
• Black blood characterizes tissue
• LGE is highly sensitive for Gadolinium retained in fibrosis or myocyte damage.
• Phase contrast can quantitate flow.