Regional right ventricular wall motion in tetralogy of fallot: a three dimensional analysis

We observed an abnormal contraction pattern in the right ventricle (RV) in postoperative tetralogy of Fallot (TOF) patients when measuring the regional contribution to global stroke volume (rSV) of 20 RV slices from apex to base. We compared the rSV method's performance with the centersurface method which offers greater flexibility in defining regions of interest. We reconstructed the RV in 3D from manually traced borders in 20 repaired TOF patients and nine normal subjects from cardiac magnetic resonance images. Wall motion was measured as the local orthogonal distance between the RV endocardium at end diastole and end systole. The RV was divided into septum, conus, and 10 free wall regions. For comparison with the rSV method the free wall regions were grouped into apical, mid, and basal levels. The RV was also divided into two other 3-part models for comparison. Both rSV and centersurface methods showed that TOF patients have diminished function at the base and increased function at the apex compared to normal. The other 3-part models were less informative because large region size obscured local function abnormalities. Septal and free wall motion differed between the groups. Two analysis methods agreed that patients with TOF have a pattern of relatively increased wall motion at the apex and diminished function at the base compared to normal. The centersurface analysis showed that characterization of the RV's complex pattern of regional function requires more than three RV subdivisions.