Role of MRI in TOF follow-upTOF symposiumOctober 25, 2013Dr Edythe Tham

OutlineQuantification of RV size & functionQuantification of pulmonary regurgitationPulmonary stenosisBranch pulmonary arteriesConduits and artificial valves

Goals 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 regurgitationTransannular patch

RVOT

Flow Quantification: Phase contrast imaging

Pulmonary RegurgitationRegion of interest

Regurgitant fraction

Criteria for pulmonary valve replacementRVEDV >170 ml/m2RVESV > 85 ml/m2RVEF < 45%Regurgitant Fraction >30%Therrien et al, AJC 2005

Relationship between RV volume and pulmonary regurgitationSamyn et al, JMRI 2007

Relationship between RV ESV & RVEFGeva 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 curvatureTOF

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 repairRPA 56%: LPA 44%

Mild proximal LPA stenosis, PG 25 mmHg

18 year old S/P TOF repair bilateral branch PA stenosisRPA 75%: LPA 25%

Peak gradients:RPA: 38 mmHgLPA: 29 mmHg

12 year female with branch PA stenosisFrom MRIRPA 82%: LPA 18%

Right pulmonary arteryLeft pulmonary artery

RVOT aneurysm

RVOT aneurysm

Conduits & artificial valves

Artifact from prosthetic valve12 year female

Prosthetic pulmonary valveMelody 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 MRINo radiationDoes not require sedation in older childrenIndependent of acoustic windowsCapability for 3D reconstructionQuantifies ventricular functionFlow quantification

Objectives:Explain the technique of cardiac MR- including the basic physics of CMRPresent an overview of the clinical applications of Cardiac MR in pediatricsTo look at future technological developments in cardiac MRMultiple contiguous sets of cine MRI sequencesParallel slices, fixed distance apart, each slice thickness is known - hence we get a 3D volume, no geometric assumptions are made, no formulasTrace endocardial borders in end-diastole and end-systoleMultiply area by slice thicknessSum results of each slice ventricular volumes

Multiple contiguous sets of cine MRI sequencesParallel slices, fixed distance apart, each slice thickness is known - hence we get a 3D volume, no geometric assumptions are made, no formulasTrace endocardial borders in end-diastole and end-systoleMultiply area by slice thicknessSum results of each slice ventricular volumes

***Andy Powell 6/01Andys June 01.PPTMPA Flow.CNV*Correlation between pulmonary regurgitation & RV EDVi in 206 patients with repaired TOFJMRI 2007, 26:934-40*Correlation between RV ESVi & RVEF in 100 patients with repaired TOFJMRI 2007, 26:934-40*AD: S/P transannular patch, Mildly dilated RV volume, RVEDI 111 ml/m2 and mildly reduced RV systolic function, RVEF 50%. Moderate pulmonary regurgitation, RF 43%. Differential flow RPA 44%: LPA 56% Preserved LV systolic function.

KJB: TOF/PA/MAPCAs, 22mm contegraDiff flow RPA 82%:LPA 18%*KJB*KJB*SG: 10yo, mixed PS/PI, Tetralogy of Fallot. s/p transannular patch in 1993 1. Severe pulmony regurgitation, regurgitant fraction 63% by MPA flow, 46% by combined branch pulmonary flow 2. Moderately dilated RV, RVEDVi 151 ml/m2 with normal systolic function, RVEF 51% 3. Dilated RVOT with aneurysm, maximum 39 mm 4. Dilated ascending aorta at 2.85 cm 5. Normal LV volume with normal systolic function1st pass MRA for pulmonary circulation2nd pass MRAMW, T21, TOF, S/P repair, severe PR RF 36%, RPA 56%, LPA 44%, mild LPA stenosis, RVEF 32%, LVEF 54%, JS, 18yo S/P TOF repair with severe PR, mod RVE, Nl RV fn, bilateral branch PA stenosisKJB: CT angio, branch PA stenosis: RPA 82%: LPA 18%PR with aneurysmAB, Hancock valve, then Melody valveLeft: KJB artifact from coil embolization of LSCA collateralsRight: AB artifact from prosthetic valveAE: Axial HASTE showing normal branch Pas in TOFTD: 39 yo male, 29 Hancock PVR/conduit, Mixed PS/PR. Moderately dilated RV, RVEDi 170 ml/m2, Reduced RV systolic function, RVEF 42%, Mild pulmonary regurgitation, RF 20%, Mildly reduced LV function, LVEF 45%

*92 adult post-TOF repairs. RV and LV LGE were common in TOF repair and were related to adverse clinical markers dysfn, ex intol, neurohormonal activation, RV LGE sig ass with clinical arrhythmiaKJB, severe RVE, +LGE RVOTAB: PA/TOF/VSD/MAPCAs, S/P unifoc/TAP 1995, BD LPA, 21 mm Hancock valve/LPA aretrioplasty 98, Melody valve 11.RAA+ MIB, small branch PAs, mid-RVFW and RVOT aneurysm, with hyokinesis, RVEF 33%, Nl LV fn