  Patient-specific cranial implants are important and necessary in the surgery
of cranial defect restoration. However, traditional methods of manual design of
cranial implants are complicated and time-consuming. Our purpose is to develop
a novel software named EasyCrania to design the cranial implants conveniently
and efficiently. The process can be divided into five steps, which are
mirroring model, clipping surface, surface fitting, the generation of the
initial implant and the generation of the final implant. The main concept of
our method is to use the geometry information of the mirrored model as the base
to generate the final implant. The comparative studies demonstrated that the
EasyCrania can improve the efficiency of cranial implant design significantly.
And, the intra- and inter-rater reliability of the software were stable, which
were 87.07+/-1.6% and 87.73+/-1.4% respectively.
