Midbrain atrophy in progressive supranuclear palsy: comparison of two dimensional planimetric- with three dimensional volumetric measurements

Two-dimensional (2D) planimetric measurements of the brainstem could be useful to differentiate patients with the clinical diagnosis of progressive supranuclear palsy (PSP) from those with other parkinsonian disorders intra vitam (1). However, planimetric 2D measurements of small structures may be inaccurate owing to partial volume effects, which depend on the rater-dependent selection of the midsagittal image and the manual traces to identify the structure. We aim here to compare the use of 2D with three-dimensional (3D) volumetric measurements. On a semiautomated basis, we measured 33 patients diagnosed with P…