Level, timing, edge convention and modality must match before a diameter difference is interpreted as growth; the magnitude is then read against the reported measurement variability.

1. Next
   Were both diameters measured at the same level, referenced to the same landmark (e.g. sinuses of Valsalva; ascending aorta at a stated distance from the STJ)?
   Anatomic level — Annulus, sinuses, STJ or ascending aorta, with the same landmark reference—SameDifferentUnknown / not recorded
   Anatomic level of the prior measurement is not recorded.