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.

sonya_at_imperial.ac.uk
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

Brickner, M. E. et al. N Engl J Med
2000342334-342
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)

4
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?

5
How to obtain a good RVOT view
6
How to obtain a good RVOT view cross cut
RVOT cross-cut
RVOT
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
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
8
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
9
Ventricular volumes
Other download say this Eg How I do LV volumes
10
How to obtain a good RPA cine
RPA
11
How to obtain a good LPA cine
LPA
Adjustment on coronal multislice useful
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
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
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
15
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

16
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
• MAPCAs if pulmonary atresia variant
• Proximity of structures to retro-sternum pre redo
  surgery
• LV as well as RV dysfunction
• FREE PR after repair

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 QpQs ratio
• Stroke volume ratio may be relevant

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
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
2006113405-413
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