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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.