Figure 2From: Effect of malaria on placental volume measured using three-dimensional ultrasound: a pilot studyIntra-observer variability of placental volume measurements. Plot of difference against mean for intra-observer variability of 145 placental volume measurements in 96 women using VOCAL ™ at 15° (A) and 30° (B) rotational angles, with mean difference and 95% limits of agreement indicated.Back to article page