TITLE:
Computer Science Tools for Manual Editing of Computed Tomographic Images: Impact on the Quality of 3D Printed Models
AUTHORS:
Jean H. D. Fasel, Jörg Beinemann, Karl Schaller, Heinz-Otto Peitgen
KEYWORDS:
Preoperative Replicas, 3D Printing, Skull, Models, Accuracy
JOURNAL NAME:
Surgical Science,
Vol.5 No.10,
October
22,
2014
ABSTRACT: Background:
Three-dimensional printing (3DP) technologies are a trendsetting topic, also in
the field of surgery. Preoperative planning for maxillofacial and neurological
surgery, for instance, increasingly involves skull models obtained by 3DP.
However, the cranial replicas currently used in this context have been shown to
not reproduce the exact anatomy of the individual patient undergoing surgery. Objective:
The present study aimed at investigating the extent to which manual editing,
using current computer software tools, can improve skull models derived from
medical images. Methods: Skull computed tomography (CT) was obtained on three
cadavers andsent to three
institutions that provide preoperative 3DP services. Each institute
independentlyperformed 3D
reconstructions, including routine manual editing, and subsequently produced
the replicas. The models were then qualitatively compared with the respective
original skull. Forquantitative
comparison surface scans of particular regions of interest were made and the
deviations assessed using 3-matic software (Materialise, Leuven, Belgium).
Results: Routine manual editing of CT images resulted in replicas that were
clear improvements over automatically generated reconstructions. This was
particularly the case for teeth artefacts and thin-walled entities (e.g.
paranasal sinuses). Conversely, however, many anatomical structures remained
incorrectly rendered (e.g. orbitae, pterygoid processes, and sella turcica).
Extraosseous calcifications had regularly not been removed. After extensive
manual editing, however, replicas were able to provide largely submillimeter
accuracy (mean deviation 0.2496 mm; standard deviation ±0.2276 mm).
Conclusions: This study confirms that manual editing with current computer
science tools does improve the quality of CT-based 3D printed skull models.
But, it also demonstrates that a number of structures remain largely incorrectly
rendered when edited in the presently used surgical framework. Conversely, it
shows that highly accurate replicas are feasible, provided that extensive
manual editing is performed.