Estimation of the volume of the cervical vertebral bodies (C3-C7) using stereological methods

Estimation of the volume of the cervical vertebral bodies (C3-C7)using stereological methodsSerdar ÇOLAKOĞLUABSTRACTInfectious diseases related to the vertebra, traumatic or non-traumatic fractures anddeformities caused to loss of the mass of the vertebral body change the height and width ofvertebral body. In such cases knowing the volume of the vertebral body has a criticalimportance for treatment and surgical interventions.This study aimed to estimate the volume of cervical vertebral body on CT imagesusing the Cavalieri principle and also assessing whether a calibration is required to obtain areliable estimation. For this aim, we used two cadaveric specimens including C3-C7vertebras. Specimens were scanned using a CT (computer tomography) machine from end toend and the obtained images of sections at a thickness of 3 and 5 mm in three anatomicalplanes were printed on standard films. The volumes of the vertebral bodies were estimated onthese films using Cavalieri principle. After this estimation the vertebral bodies were dissectedfrom each other and surrounding tissue. The actual volumes of the isolated vertebras weremeasured using fluid displacement technique and the obtained values were used as ?the goldstandard? of this study. The estimated and measured volumes of the vertebral bodies using theCavalieri principle and the fluid displacement technique were ranging between 3.35-6.67 cm3and 3.15-5.50 cm3, respectively. Although there was observed a high correlation (r=0.937)between the estimated and measured values, but it was found a significant difference incomparison of these volume values (p<0.05). This deviation from the actual values may beattributed to technique used in CT images. We assessed coefficients for each section planesand thickness to overcome the systematical error. The corrected volume values of theCavalieri principle did not show significant difference from the actual volumes of thevertebral bodies (p>0.05).In conclusion, these results showed that the cervical vertebral body volumes can beestimated using CT images and the systematic error of the volume estimation can be correctedusing the proposed coefficients for each section plane and thickness.Key words: Cervical vertebra, vertebral body, volume, Cavalieri principle, computedtomography