Role of MRI in TOF follow-up

TOF symposium

October 25, 2013

Dr Edythe Tham

Outline

Quantification of RV size & function

Quantification of pulmonary regurgitation

Pulmonary stenosisBranch pulmonary arteriesConduits and artificial valves

Goals of cardiac MRIGoals of cardiac MRIQuantification of RV & LV

volumes and function (RVEF)Quantification of pulmonary

regurgitant fraction (RF)Anatomy of the RVOT & branch

pulmonary arteries (and aorta)Assessment of myocardial

fibrosis

RV volumes

Pulmonary regurgitation

Transannular patch

RVOT

Flow Quantification: Phase contrast imaging

Pulmonary Regurgitation

Region of interest

Regurgitant fraction

Criteria for pulmonary valve replacement

RVEDV >170 ml/m2

RVESV > 85 ml/m2

RVEF < 45%Regurgitant Fraction >30%

Therrien et al, AJC 2005

Relationship between RV volume and pulmonary regurgitation

Samyn et al, JMRI 2007

Relationship between RV ESV & RVEF

Geva et al, JACC 2004

RVEDVi 111 ml/m2RVESVi 56 ml/m2RVEF 50%

LVEF 60%

17 year female, S/P TAP

RegurgitantFraction 43%

RVEDVi 178 ml/m2RVESVi 150 ml/m2RVEF 16%

LVEF 28%

11 year female with TOF/PAS/P RV-PA conduit

Normal septal curvature

TOF

Regurgitant fraction57%

Peak velocity 2 m/s= Peak gradient 16 mmHg

Pulmonary stenosis

10 year femaleS/P TAP

Mixed disease –

Mild PS: 20 mmHgModeral PR: 34%

Magnetic Resonance

AngiographyBranch pulmonary arteries

21 year male S/P TOF repair

RPA 56%: LPA 44%

Mild proximal LPA stenosis, PG 25 mmHg

18 year old S/P TOF repair – bilateral branch PA stenosis

RPA 75%: LPA 25%

Peak gradients:RPA: 38 mmHgLPA: 29 mmHg

12 year female with branch PA stenosis

From MRIRPA 82%: LPA 18%

Right pulmonary artery Left pulmonary artery

RVOT aneurysm

RVOT aneurysm

Conduits & artificial valves

Artifact from prosthetic valve

12 year female

•Prosthetic pulmonary valve•Melody valve

38 year maleS/P 29 mm Hancock valve RVEDVi 170 ml/m2RVESVi 98 ml/m2RVEF 42% RF 20%Peak velocity 3 m/s = PG 36 mmHg

Melody valve

Circulation, 2006;113:405-413

RVEF 33%

Indications for cardiac MRIBaseline post-TOF repair at 7-10

years (no sedation required)Follow up every 1-3 years

depending on clinical statusYearly MRI if: symptomatic or

evidence of RV dysfunction

Cardiac MRI: DisadvantagesNot portableContraindications:

pacemaker/AICDAffected by metallic artifacts eg

prosthetic valves, stents

Advantages of MRI

No radiationDoes not require sedation in older

childrenIndependent of acoustic windowsCapability for 3D reconstructionQuantifies ventricular functionFlow quantification