An in-vitro study to assess the feasibility, validity and precision of capturing oncology facial defects with multimodal image fusion

Abstract

This method for merging two independent scans to produce a fused model shows strong potential as an accurate and repeatable method of capturing facial defects. Further research is required to explore its clinical use.

Accuracy of capturing oncology facial defects with multimodal image fusion versus laser scanning

“…The method of multimodal image fusion has previously been shown to have potential as a true and precise method of capturing facial defects based on in-vitro data. 11 This approach combines the initial short capture time of stereophotogrammetry with the ability of the structured light scanner to capture the internal surfaces of the defect. Whilst multimodal image fusion had a greater mean global absolute deviation than the laser scanner, this appeared to be within clinically acceptable limits.…”

“…For analysis, deviation was assessed across the entire surface of the CBCT mask and therefore there is a risk that the results could have underestimated errors at clinically important areas such as the prosthesis margins. 11 However, it was also important to not only capture the defect but also take sufficient accurate data on the surrounding facial features so that the contours of a prosthesis could be made in harmony with the surrounding tissues. The color error maps did indicate that this was not the case as the greatest error was usually located away from clinically important areas.…”

“…3D models were produced for each cast using multimodal image fusion and the method has been documented in a previous article. 11 Prior to scanning the casts, the stereophotogrammetry and optical structured light scanner were calibrated utilizing calibration targets. The external facial features were then captured using stereophotogrammetry (DI3D; Dimensional Imaging Ltd DI4D) ( Fig.…”

“…In order to overcome this the use of optical scanning to supplement the missing data from the deeper defect area based on a multimodal imaging technique has been suggested. 11 Laser surface scanning is an alternative technique to stereophotogrammetry and has been successfully introduced into the workflow for producing facial prostheses. 6,12 As with stereophotogrammetry, laser scanning of deeper regions and undercuts is limited by the separation of the laser line generator and the receptor camera.…”

An <i>in vitro</i> study of digital impressions and three-dimensional printed models of orbital defects using mobile devices and monoscopic photogrammetry

“…The built-in iterative closest point algorithm then automatically aligned each PhM to the corresponding reference ScM. The Hausdorff distance between the two point clouds was used to visualize the facial superposition error between the PhMs and the ScM [13].…”