Accuracy and precision of angiographic volumetry methods for left and right ventricle

We imaged and quantified 60 ventricle casts (30 LV, 30 RV) to evaluate the accuracy and reliability of angiographic ventricle volumetry. We analyzed the seven biplane methods most frequently used in clinical routine: Arcilla, Arvidsson, Dodge, Ferlinz, Simpson (LV + RV) and Wynne. The ventricle contours were defined by (1) manual drawing on the computer screen, (2) manual drawing using a graphical tablet and (3) automatic contour detection. A high inter-class variation in volume accuracy between the different methods was observed (S.D. = 12.7 ml). The volume methods for the LV (mean differences MD(LV): [-2.2, +8.5] ml, average MD(LV) = 1.8 ml) are more accurate than for the RV (MD(RV): [-11.4, +33.1] ml, average MD(RV) = 12.1 ml). The intrinsic error is about the same for all approaches and is very high: average S.D. = 20 ml, RMS = 185 ml. Manual contour definition results in a volume over-estimation (average MD(man) = +32.8 ml, r = 0.731) compared with automatic contour detection (average MD(auto) = +6.2 ml, r = 0.810). LV hypertrophy results in a volume under-estimation of the LV (MD(LV) = -7 ml) and an over-estimation of the RV (MD(RV) = +6 ml). RV hypertrophy leads to the opposite effect. It was shown that ventricle volumetry and the calculation of derived parameters (ejection fraction) is extremely case dependent and can only be an estimate of the actual value.