Di Chiro used several equations for measuring the volume of the pituitary gland. The author is from the National Institute of Neurological Diseases and Blindness at NIH.
The pituitary gland is roughly an ellipsoid.
volume in mL based on direct measurements =
= (4 / 3) * PI() * ((width in cm) / 2) * ((length in cm) / 2) * ((height in cm) / 2) *
When estimating the pituitary size from the size of the sella turcica seen on plain X-rays Di Chiro used a correction factor of 0.5112 that takes into account:
(1) X-ray magnification effect
(2) difference between roentgenographic and actual volume
(3) correction for 4 * PI() / 3 * ((0.5)^3) = 0.524
volume in mL based on size of the sella turcica =
= 0.5112 * (length in mm) * (width in mm) * (height in mm) / 1000
• 1000 is for conversion from cubic mm to cubic cc (mL).
• Note that the actual dimensions are used rather than the radii, which represents factor of 8.
• If you take the previous equation, 4 * PI() / 3 / 8 = 0.5236. 0.5112 is 97.6% of this value.
• If the density of the pituitary gland is known then the weight can be estimated.
The different parts of the pituitary gland normally represent the following percentages of pituitary weight:
Percent of Total Weight
from Figure 17, page 36
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Specialty: Endocrinology, Clinical Laboratory, Neurology, Immunology/Rheumatology