Table 3. MRI Features of Right Ventricular Adaptation and Failure.

Feature	Significance	Parameter indicating RV dysfunction	Prognostics
RV mass	Increased mass correlates with mPAP. Mass decreases in response to sildenafil therapy30, 130.		Non-significant trend towards increased mortality.
RV end diastolic volume index (RVEDVI)	Dilatation and increased volume signifies a progression of RV pressure overload.	≥ 84mL/m	Associated with increased mortality38.
RV Ejection Fraction (RVEF).	Better mortality prediction than PVR15. Increased in response to sildenafil therapy130.	<35%	Increased mortality is independent of baseline PVR and PVR change with therapy15.
RV longitudinal shortening	TAPSE measurement equivalent15.	<15 mm	Non-survivors had reduced longitudinal shortening (14+7mm vs. 20+5mm)129.
RV transverse shortening	Incorporates free wall and septal movements129.		Non-survivors had reduced shortening in segments 2-7.
RV Fractional area change (RV FAC)	Used as a surrogate for ejection fraction	< 24%	Non-survivors -decreased at baseline (24%±10 vs. 31%±9) -1 year follow-up decreased by 17%±10129.
LV end diastolic volume	Decreased with septal bowing with impaired LV filling	≤ 40 mL/m	Increased mortality238.
Left ventricular septal-to-free-wall curvature ratio	Used to estimate RVSP, objective measurement of septal bowing into the LV131.	Ratio >0.67	87% sensitivity, 100% specificity for elevated RVSP43.
LV Stroke Volume Index (LV SVI)	Normal SV indicates RV adapted to increased afterload - 10mL changes in SV are significant.132	LV SVI ≥25mL/m	Increased mortality238.