MRI protocol for post-repaired TOF

Transcription

1 2012 NASCI MRI protocol for post-repaired TOF Taylor Chung, M.D. Associate Director, Body and Cardiovascular Imaging Department of Diagnostic Imaging Children s Hospital & Research Center Oakland Oakland, California, U.S.A.

2 Disclosures Off label usage of Gadolinium contrast agent No relevant financial disclosures pertaining to the subject of this presentation

3 Outline Goals of MR examination for repaired TOF A clinical MR scanning protocol Clinical examples

4 Goals of MR exam Dictated by post-operative outcomes of patients with TOF repaired

5 Goals of MR exam Dictated by post-operative outcomes of patients with TOF repaired Pulmonary regurgitation and progressive RV dilation Biventricular function Pulmonary artery stenoses / differential flow Residual shunts

6 Goals of MR exam Dictated by available treatment options Surgical pulmonary valve replacement Re-operation through prior sternotomy What is under sternum? Prior anatomic information on coronary arteries? Percutaneous pulmonary valve replacement Size and shape of RVOT / MPA Location of proximal coronary arteries

7 Necessary Data Biventricular volumes / function Anatomy of RVOT / MPA and peripheral PA s Degree of pulmonary regurgitation Optional: Differential flow to right and left lungs Tricuspid inflow pattern Coronary artery anatomy Areas of myocardial fibrosis

8 A Clinical Protocol SSFP localizers Cine SSFP (vertical long axis, 4-chamber, short axis, RVOT) Cine fast gradient echo for PA bifurcation Cine phase contrast (Asc Ao, MPA) (optional: RPA, LPA, AV valve, IVC /Des Ao) CE-MRA 3D-SSFP coronary MRA (optional) Viability (optional)

9 Breath-hold vs non breath-hold Need accurate ventricular volumes Patient has to be mature enough to hold breath reproducibly Breath hold duration needs to be relatively short given multiple breath hold Important - pre-exam instructions by MR technologists For borderline patients, low threshold to switch to non-breath-hold technique Non breath-hold exam can be a shorter exam

10 Short axis vs axial for RV volumes Short axis Can be difficult to segment at basal locations Visualization of segmental wall motion Easier to detect inconsistent breath-holding Axial* Easy to segment at base of RV Not standard compare to many clinical data methodology Not optimal for LV function assessment Partial volume of diaphragm when heart is not transverse Inconsistent breath-holding more difficult to detect * Fratz S et al. Am J Card 2009

11 Adjustments Short axis Parallel to tricuspid valve plane to minimize error in contouring at basal location Can yield sub-optimal basal slices for LV when RV is large Axial Change to an oblique axial / oblique 4-chamber plane Modify 4-chamber orientation to be along diaphragmatic surface as seen on 2-chamber long axis and short axis Minimize error from partial volume of diaphragm

12 Sedated 5-year-old boy freely breathing h/o TOF / PA S/P complete repair with RV-PA conduit Echo shows dilated RV MRI to evaluate RV size / function, pulm regurgitation Axial Sagittal Coronal Single phase SSPF triggered at late diastole

13 Sedated 5-year-old boy freely breathing with h/o TOF / PA VLA 4CH SA Interactive mode with SSFP to rapidly achieve approximate scan planes for future use in exam

14 Sedated 5-year-old boy freely breathing with h/o TOF / PA Free-breathing Cine SSFP 3 NSA SENSE = 2

15 Sedated 5-year-old boy freely breathing with h/o TOF / PA Oblique axial / pseudo-4ch stack for RV volume assessment

16 Sedated 5-year-old boy freely breathing with h/o TOF / PA RVEDV = 153 ml/m2; RVESV = 90 ml/m2; RVEF = 42%;

17 Sedated 5-year-old boy freely breathing with h/o TOF / PA Short axis parallel to tricuspid valve plane

18 Sedated 5-year-old boy freely breathing with h/o TOF / PA RVEDV=153 ml/m2; RVESV=84 ml/m2; RVEF=45%; CO=3.9 l/min

19 Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for opening up PA bifurcation Cine fast gradient echo for higher spatial resolution Note saturation band over anterior chest wall to eliminate ghosting artifacts from respiratory motion Line up the proximal RPA and LPA from the coronal and sagittal localizers to open up the PA bifurcation

20 Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for RVOT view RVOT view help to localize scan plane for phase contrast of MPA Adjust scan plane along MPA Line up RVOT from coronal localizers

21 Sedated 5-year-old boy freely breathing with h/o TOF / PA

22 RVOT Cine SSFP Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for flow quantification of MPA Cine phase contrast Shortest TE, TR = 10 ms, FA = x 1.5 x 6 mm; 2 NSA, SENSE = 2 HR = 71 bpm; 24 phases; 1:10 min Cine FTE Flow Quantification result: MPA: 28 ml/beat; 2 l/min

23 RVOT Cine FTE Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for flow quantification of MPA Cine phase contrast Shortest TE, TR = 10 ms, FA = x 1.5 x 6 mm; 2 NSA, SENSE = 2 HR = 71 bpm; 24 phases; 1:10 min SSFP coronal localizer Flow Quantification result: MPA: 42 ml/beat; 3 l/min

24 Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for flow quantification of Asc Aorta Flow Quantification result: Asc Ao: 38 ml/beat; 2.9 l/min

25 Optional sequences

26 Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for flow quantification of RPA

27 Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for flow quantification of LPA

28 Sedated 5-year-old boy freely breathing with h/o TOF / PA Plan scan for flow quantification of AV valves

29 Sedated 5-year-old boy freely breathing with h/o TOF / PA Single dose Gad CE-MRA with SENSE, Keyhole

30 Coronary MRA Cooperative 17-year-old with TOF repaired Whole Heart MRA on 3T 1.5 x 1.5 x 3 mm acquired matrix 1.5 x 1.5 x 1.5 reconstructed 40 slices, 1:22 min; TFE factor 24 Resp navigator efficiency ~ 40% TR/TE/FA=4.1/1.3/20 o 1 NSA; SENSE = 2 Hi-res coronary MRA on 3T 0.8 x 0.8 x 2 mm acquired matrix 0.6 x 0.6 x 1 reconstructed 30 slices, 5:32min; TFE factor 14 Resp navigator efficiency ~ 40% TR/TE/FA=7.3/2.2/20 o 4 NSA; SENSE = 3

31 Viability Sedated freely breathing 6-year-old patient with TOF repaired 3D-PSIR with respiratory navigator Triggered to end-systole

32 Acknowledgements Eric Padua, Gregory Kurio Children s Hospital & Research Center Oakland Oakland, California, U.S.A. David Hitt Philips Healthcare Cleveland, Ohio, U.S.A. Rajesh Krishnamurthy, Lorna Browne, Wesley Vick, III, Michael D Taylor, Timothy Slesnick Texas Children s Hospital, Houston, Texas, U.S.A. Raja Muthupillai St. Luke s Episcopal Hospital, Texas Heart Institute Houston, Texas, U.S.A.

33 Thank You