Correction to: Assessing size of pituitary adenomas: a comparison of qualitative and quantitative methods on MR

We have incorrectly described the ellipsoid equation as being calculated using maximal diameters. It is in fact calculated using half the maximal diameter, i.e. the maximal radii. The diameter is initially recorded on the MRI images (as per Fig. 1), as the lesions do not have a defined midpoint.