Comparison of three methods for the estimation of total intracranial volume: stereologic, planimetric, and anthropometric approaches.

There is a well-known close relationship between the total intracranial volume (TIV) and the brain size. Several studies in different countries have estimated the cranial capacity, which indirectly reflects the brain volume. However, we have not seen a study evaluating the results of the methodologies for the assessment of TIV. This study was carried out on 30 normal subjects whose ages ranged between 19 and 77 years old (males, 18; females, 12). Three different methods were used to assess the TIV. The mean (+/-SD) estimated TIV using linear dimensions method in males and females were 1416.8 +/- 64 cm and 1291.9 +/- 152 cm, respectively. The mean estimated TIV using point counting method in males and females was 1474 +/- 93 cm and 1252 +/- 72 cm, respectively. By using the planimetric method of the mean and SD of TIV, male and females were 1492.1 +/- 74 cm and 1319.6 +/- 100 cm, respectively. There were no statistical difference between TIV measurements obtained using the optimized stereologic technique and planimetry (P > 0.05). TIV between males and females was statistically significant (P < 0.001). This study showed that there are minor differences among the given 3 distinct methods. With the disadvantage of requiring more time to apply, the planimetry and point counting methods provide more assumption-free results than the anthropometric approach. However, the anthropometric method can be applied to assess TIV without needing sophisticated tools.