OBJECTIVE: To compare the intraobserver reproducibility of real three-dimensional ultrasonography (3DUS) with virtual ultrasonography using multiplanar and volumetric reformations. MATERIALS AND METHODS: A total of 132 blocks from 44 evaluations of 26 conceptuses were prospectively examined. The gestational age determined by echography ranged from eight weeks and eight weeks and six days in 18 conceptuses and ten weeks and ten weeks and six days in 26 conceptuses. The following structures were analyzed by 3DUS: crown-rump length, gestational sac, amniotic sac, nuchal translucency, omphalomesenteric duct, vitellin vesicle, upper limbs, lower limbs, head-thorax distinction, lateral view of the face, coronal view of the face, ear implantation, lateral view of the spine, coronal view of the spine, and closed abdominal wall. Three blocks were obtained from each conceptus for virtual ultrasonography. Student's t test, McNemar test and kappa statistics were used for the statistical analysis. RESULTS: In group I, real multiplanar 3DUS versus 3D virtual multiplanar ultrasonography, the analysis of continuous variables showed significant differences for all variables. The analysis of categorical variables showed no significant differences in any of the variables. In group II, real volumetric 3DUS versus virtual volumetric ultrasonography, showed significant differences only for ear implantation. The results of the analyses of categorical variables were consistent for most of the variables analyzed in both groups. CONCLUSION: We concluded that there is intraobserver reproducibility of virtual ultrasonography using multiplanar and volumetric reformations.

Keywords: Virtual ultrasonography, Three-dimensional ultrasonography, First trimester