1. ‘How I do’: CMR of repaired tetralogy of Fallot
Sonya V. Babu-Narayan MB BS BSc MRCP
Department of CMR
Royal Brompton Hospital
For scmr.org 07/2006
This presentation posted for members of scmr as an educational guide – it represents the views and practices of the author, and not necessarily those of SCMR.
‘How I do’ : CMR of repaired tetralogy of Fallot

2. CMR in repaired tetralogy of Fallot
Include:
Measurements of biventricular volumes, EF, mass
RVOT cines, 2 views
Aortic root +/- AR quantification
Quantify pulmonary regurgitant fraction
Assessment of LPA and RPA
Ensure reproducible technique:
Serial CMR aids PVR timing
Lgf folder/rs
Brickner, M. E. et al. N Engl J Med 2000;342:
‘How I do’ : CMR of repaired tetralogy of Fallot

3. “Basic Recipe” (~ 30 mins)
3 axis multislice stack: Transverse, sagittal, coronal
Use Half Fourier single shot TSE or single shot SSFP
Initial pilots then:
cines
2Ch, 4Ch and SA stack
RVOT – 2 views
LVOT – 2 views
Velocity mapping
Pulmonary regurgitant fraction (PRF)
All patients
Consider
AoV view cine for measurement aortic root
Branch PAs if not clearly unobstructed on transverse stack
Further long axis RV views: RV “in and out”/ oblique/2ch (see below)
Further velocity mapping
2 views for peak PA velocity
Ao to add to PA for PRF above for Qp:Qs shunt calculation
Branch PA velocity mapping
3d angiography
MAPCA’s / planning intervention (eg transcatheter PV implantation)
‘How I do’ : CMR of repaired tetralogy of Fallot

4. ‘How I do’ : CMR of repaired tetralogy of Fallot
Initial Acquisition
Multislice stack in transverse, sagittal and coronal
We do: transverse half Fourier TSE, and SSFP for coronal + sagittal
transverse half Fourier TSE; easier to measure dimensions of structures such as aortic root and SSFP multislice gives advantage of jet recognition early on
Advantages of comprehensive multislice imaging include:
subsequent piloting of cines
ability to answer specific additional questions retrospectively
such as presence of LSVC?
right aortic arch?
location of coronary sinus?
‘How I do’ : CMR of repaired tetralogy of Fallot

5. How to obtain a good RVOT view
‘How I do’ : CMR of repaired tetralogy of Fallot

6. How to obtain a good RVOT view cross cut
RVOT “cross-cut”
You may now wish to append your first RVOT view and realign the plane locating
on this second cross cut RVOT to improve alignment further
These two views provide a minimum data set for alignment of velocity acquisitions
‘How I do’ : CMR of repaired tetralogy of Fallot

7. Advantages in RVOT obstruction
Characterisation level of obstruction and flow;
sub-infundibular stenosis
assessment of branch PAs
Unrestricted views of RV anatomy
multiplanar
Assessment of associated abnormalities
Anterior conduits well visualised
Infundibular pulmonary stenosis
‘How I do’ : CMR of repaired tetralogy of Fallot

8. ‘How I do’ : CMR of repaired tetralogy of Fallot
Pulmonary regurgitant fraction
In practice, use other views to check alignment – at least one other RVOT plane (RVOT cross-cut above) and potentially the transaxial haste, a bifurcation PA view, in-plane velocity mapping or oblique RV view
‘How I do’ : CMR of repaired tetralogy of Fallot

9. ‘How I do’ : CMR of repaired tetralogy of Fallot
Ventricular volumes
Other download say this
Eg How I do LV volumes
‘How I do’ : CMR of repaired tetralogy of Fallot

10. How to obtain a good RPA cine
‘How I do’ : CMR of repaired tetralogy of Fallot

11. How to obtain a good LPA cine
Adjustment on coronal multislice useful
‘How I do’ : CMR of repaired tetralogy of Fallot

12. How to obtain a bifurcation PA cine
PA Bifurcation cine
If the LPA is markedly higher in take off than the RPA it may be impossible to align a bifurcation cine view
‘How I do’ : CMR of repaired tetralogy of Fallot

13. Assessment of LPA Stenosis
Cine
In-plane flow
Through plane flow
Mild LPA origin stenosis
Use in-plane to help align through-plane for more accurate peak velocity location or better alignment for flow volume measurements
NBH velocity mapping at RPA and LPA can be used to quantify flow to R and L lung respectively, that is, differential lung perfusion (nb. normally greater flow to the R lung than the L lung)
Lack of pulsatility in distal pulmonary vessels may suggest more significant stenosis
Assessment of branch pulmonary artery stenosis is important in repaired Fallot as these may be a therapeutic target particularly if there is significant pulmonary regurgitation
‘How I do’ : CMR of repaired tetralogy of Fallot

14. RVOT Akinesia/Aneurysm
Dyskinetic and or aneurysmal areas of the RVOT are frequently present in adults with repaired tetralogy of Fallot and vary in size
Davlouros et al, JACC 2002
‘How I do’ : CMR of repaired tetralogy of Fallot

15. ‘How I do’ : CMR of repaired tetralogy of Fallot
RV measurement in ACHD
RV trabeculations:
Coarse, thickened
significant in summed volume
Planimetry challenging
Determining valve level may be difficult
TV: may be difficult
PV: potentially absent or remnant
RVOT
can be dilated and dyskinetic
may have no effective pulmonary valve
We count a dilated or aneurysmal RVOT as part of the RV
it lies beneath the PV annulus
So belongs to the right ventricle
Use stroke volume as check
velocity mapping of Ao and Pa
a useful cross-check on manual contour data
Establish your own, reproducible protocol for the RV
‘How I do’ : CMR of repaired tetralogy of Fallot

16. ‘How I do’ : CMR of repaired tetralogy of Fallot
Residual defects, associated abnormalities, post-operative complications, variants
The following may be present:
Residual VSD
Residual PS
Other intra-cardiac associated abnormalities
eg ASD, AVSD, PFO
Left SVC
Right aortic arch
Branch PA deformation or stenosis
Ascending aortopathy / aortic root dilatation
MAPCA’s if pulmonary atresia variant
Proximity of structures to retro-sternum pre redo surgery
LV as well as RV dysfunction
FREE PR after repair
‘How I do’ : CMR of repaired tetralogy of Fallot

17. Identifying residual VSD / patch leak
Patch leak may be seen in:
LVOT view
RV in and out
RV oblique views
SA view as opposite
If uncertain:
cross-cut a SA view where a jet core is suspected
Add NBH velocity:
Aorta and PA
Calculate Qp:Qs ratio
Stroke volume ratio may be relevant
‘How I do’ : CMR of repaired tetralogy of Fallot

18. Additional RV Long Axis Views
These additional RV views can be useful in contributing to qualitative assessment of regional and global RV function. Residual VSD patch leak is sometimes well seen on the “RV in and Out” cine which shows the AoV in SA and the VSD patch as well as PV and TV
‘How I do’ : CMR of repaired tetralogy of Fallot

19. Late Gadolinium In Fallot - Research
LGE CMR can be extended to the sub-pulmonary, hypertrophied RV and appears sensitive & surgical scarring appears ubiquitous in older repaired TOF
LV pathology is less common
Evidence of fibrosis is:
in specific locations
to varying extent
sometimes in areas
remote from surgical sites
Increased LGE relates to
exercise intolerance
neurohormonal activation
ventricular dysfunction
RV LGE Score predicted clinical arrhythmia
Babu-Narayan SV et al. Circulation 2006;113:
‘How I do’ : CMR of repaired tetralogy of Fallot

20. Late Gadolinium In Fallot - Clinical
Prospective data pending -a hot research topic
May be useful with LV dysfunction
Can be challenging
Adult patients have surgical scarring
Flow-limiting CAD uncommon without symptoms
Caution when interpreting small areas of LGE
Call abnormality only if proven in 2 views
phase swap, cross-cutting, or both
‘How I do’ : CMR of repaired tetralogy of Fallot