[The methodology and accuracy of MRI-based orbital volume calculations].

Objective: The aim of the present work was to establish a method for orbital volume calculation based on MR scanning data for the sake of better radiation hygiene.

Materials And Methods: The orbital volumes of 35 ophthalmologically healthy children were calculated on the basis of MRI scans. After data transfer to a separate workstation, volumetric analysis was carried out by two independent radiologists using semi-automated software. The accuracy of the calculated values was compared with orbital volumes measured by anatomic preparations and given in studies by various authors.

Results: Volume calculation was possible in all patients using MRI data. There is an acceptable agreement with the presented anatomic facts and the measured values of Bentheley. In the Wilcoxon test there was not a big difference between the courses of the values (p = 0.507).

Conclusion: Even though we can obtain a better image of the bizarre structure of the bony orbits with CT, MR-based volumetry of the orbit is a reliable method and is not burdened by radiation exposure. It can thus be an important condition for the planning and the controlling of modern therapeutic concepts in treating anophthalmos and microphthalmos.