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 stenosis Branch pulmonary arteries Conduits and artificial valves

Goals of cardiac MRI Quantification 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/m 2 RVESV > 85 ml/m 2 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/m2 RVESVi 56 ml/m2 RVEF 50% LVEF 60% 17 year female, S/P TAP

Regurgitant Fraction 43%

RVEDVi 178 ml/m2 RVESVi 150 ml/m2 RVEF 16% LVEF 28% 11 year female with TOF/PA S/P RV-PA conduit

Normal septal curvature TOF

Regurgitant fraction 57% Peak velocity 2 m/s = Peak gradient 16 mmHg

Pulmonary stenosis

10 year female S/P TAP Mixed disease – Mild PS: 20 mmHg Moderal PR: 34%

Magnetic Resonance Angiography Branch 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 mmHg LPA: 29 mmHg

12 year female with branch PA stenosis From MRI RPA 82%: LPA 18%

Right pulmonary artery Left pulmonary artery

RVOT aneurysm

Conduits & artificial valves

Artifact from prosthetic valve 12 year female Prosthetic pulmonary valve Melody valve

38 year male S/P 29 mm Hancock valve RVEDVi 170 ml/m2 RVESVi 98 ml/m2 RVEF 42% RF 20% Peak velocity 3 m/s = PG 36 mmHg

Melody valve

Circulation, 2006;113:

RVEF 33%

Indications for cardiac MRI Baseline post-TOF repair at 7-10 years (no sedation required) Follow up every 1-3 years depending on clinical status Yearly MRI if: symptomatic or evidence of RV dysfunction

Cardiac MRI: Disadvantages Not portable Contraindications: pacemaker/AICD Affected by metallic artifacts eg prosthetic valves, stents

Advantages of MRI No radiation Does not require sedation in older children Independent of acoustic windows Capability for 3D reconstruction Quantifies ventricular function Flow quantification