Segmentation Methods for Micro CT Images: A Comparative Study Using Human Bone Samples

Rovaris, Karla; Queiroz, Polyane Mazucatto; Vasconcelos, Karla de Faria; Corpas, Livia; Silveira, Bernardo Mattos da; Freitas, Deborah Queiroz

doi:10.1590/0103-6440201801385

Cited by 10 publications

(13 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The additional surface distance analysis between the pre-and post-simmering micro-CT showed an average surface difference of − 0.043 +/− 0.124 mm (mean +/− SD) indicating a minor shrinkage of the bones after simmering (Table 3, Figure 11). However the measured shrinkage was less than the 0.5 mm boiling shrinkage reported in literature 19 and less then the 0.05 mm micro-CT resolution. Therefore, we expect that the simmering had minimal to no influence on the differences between the sCT and CT saw guides placement error, especially since the same bones were used for both modalities.…”

Section: Appendixcontrasting

confidence: 61%

“…A 3D-bone model comparison was performed on semiautomatic bone segmentations of the sCT-, CT-and micro-CT scans generated in Mimics (v21, Materialize NV, Leuven, Belgium). sCT-and CT-segmentations were created based on the thresholding method from Van den Broeck et al [17] and the micro-CT with Otsu's [18] automatic thresholding based on Rovaris et al [19] (Fig. 3).…”

Section: D Bone Model Generation and Comparisonmentioning

confidence: 99%

See 1 more Smart Citation

3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow

et al. 2021

View full text Add to dashboard Cite

Background Three-dimensional (3D)-printed saw guides are frequently used to optimize osteotomy results and are usually designed based on computed tomography (CT), despite the radiation burden, as radiation-less alternatives like magnetic resonance imaging (MRI) have inferior bone visualization capabilities. This study investigated the usability of MR-based synthetic-CT (sCT), a novel radiation-less bone visualization technique for 3D planning and design of patient-specific saw guides. Methods Eight human cadaveric lower arms (mean age: 78y) received MRI and CT scans as well as high-resolution micro-CT. From the MRI scans, sCT were generated using a conditional generative adversarial network. Digital 3D bone surface models based on the sCT and general CT were compared to the surface model from the micro-CT that was used as ground truth for image resolution. From both the sCT and CT digital bone models saw guides were designed and 3D-printed in nylon for one proximal and one distal bone position for each radius and ulna. Six blinded observers placed these saw guides as accurately as possible on dissected bones. The position of each guide was assessed by optical 3D-scanning of each bone with positioned saw guide and compared to the preplanning. Eight placement errors were evaluated: three translational errors (along each axis), three rotational errors (around each axis), a total translation (∆T) and a total rotation error (∆R). Results Surface models derived from micro-CT were on average smaller than sCT and CT-based models with average differences of 0.27 ± 0.30 mm for sCT and 0.24 ± 0.12 mm for CT. No statistically significant positioning differences on the bones were found between sCT- and CT-based saw guides for any axis specific translational or rotational errors nor between the ∆T (p = .284) and ∆R (p = .216). On Bland-Altman plots, the ∆T and ∆R limits of agreement (LoA) were within the inter-observer variability LoA. Conclusions This research showed a similar error for sCT and CT digital surface models when comparing to ground truth micro-CT models. Additionally, the saw guide study showed equivalent CT- and sCT-based saw guide placement errors. Therefore, MRI-based synthetic CT is a promising radiation-less alternative to CT for the creation of patient-specific osteotomy surgical saw guides.

show abstract

Section: Appendixcontrasting

confidence: 61%

Section: D Bone Model Generation and Comparisonmentioning

confidence: 99%

3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow

et al. 2021

View full text Add to dashboard Cite

show abstract

“…36 The differences observed in the current study highlight the influence of the post-processing algorithms on the analysis of dental materials by micro-CT. 37 Thresholding can be performed by simple global methods or by adaptive methods using CTAn software. 9 Our study used the adaptive method because it applies local threshold values instead of a single global method. As a result, segmentation could be improved by determining the optimal threshold value of each voxel within its neighborhood.…”

Section: Discussionmentioning

confidence: 99%

“…21 In this method, the examiner segments the images visually, and records the threshold values for each sample. 9 The MeVisLab (MeVis Research, Bremen, Germany) protocol uses a semi-interactive livewire boundary extraction, 10 in which the user moves the mouse from a manually selected point, and a livewire boundary selects and wraps around the object of interest. New points are then selected, until the boundary has been delimited and the area has been segmented.…”

Section: Image Segmentation and Volume Calculationmentioning

confidence: 99%

“…8 Several segmentation methods are available and may have distinct influences on the outcomes. 9 Manual segmentation is a time-consuming task requiring an experienced operator, with low repeatability and reproducibility. 10 Conversely, semi-automatic and automatic methods are faster, and new, less operator-dependent mathematical processing algorithms are being developed to process large volumes of data.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

How image-processing parameters can influence the assessment of dental materials using micro-CT

et al. 2020

View full text Add to dashboard Cite

Purpose: The aim of this study was to evaluate the influence of voxel size and different post-processing algorithms on the analysis of dental materials using micro-computed tomography (micro-CT). Materials and Methods: Root-end cavities were prepared in extracted maxillary premolars, filled with mineral trioxide aggregate (MTA), Biodentine, and Intermediate Restorative Material (IRM), and scanned using micro-CT. The volume and porosity of materials were evaluated and compared using voxel sizes of 5, 10, and 20 μm, as well as different software tools (post-processing algorithms). The CTAn or MeVisLab/Materialise 3-matic software package was used to perform volume and morphological analyses, and the CTAn or MeVisLab/Amira software was used to evaluate porosity. Data were analyzed using 1-way ANOVA and the Tukey test (P<0.05). Results: Using MeVisLab/Materialise 3-matic, a consistent tendency was observed for volume to increase at larger voxel sizes. CTAn showed higher volumes for MTA and IRM at 20 μm. Using CTAn, porosity values decreased as voxel size increased, with statistically significant differences for all materials. MeVisLab/Amira showed a difference for MTA and IRM at 5 μm, and for Biodentine at 20 μm. Significant differences in volume and porosity were observed in all software packages for Biodentine across all voxel sizes. Conclusion: Some differences in volume and porosity were found according to voxel size, image-processing software, and the radiopacity of the material. Consistent protocols are needed for research evaluating dental materials.

show abstract

Evaluation of curved root canals filled with a new bioceramic sealer: A microcomputed tomographic study using images with different voxel sizes and segmentation methods

Pinto

Torres

Lucas-Oliveira

et al. 2021

Microscopy Res & Technique

View full text Add to dashboard Cite

The aim of this study was to investigate the filling ability of a new premixed bioceramic sealer in comparison with an epoxy resin-based sealer in curved root canals using different segmentation methods and voxel sizes in micro-CT images. Twelve curved mesial roots of mandibular molars with two separated canals were selected.All root canals were prepared by using HyFlex EDM files size 25/.08 and filled by the single cone technique and Bio-C Sealer or AH Plus (n = 12). The samples were scanned by micro-CT at 5 μm. The images were analyzed at 5, 10, and 20 μm for the volumetric analysis of voids in filling. Visual image segmentation was performed by two examiners, and the automatic segmentation was accomplished for comparison.Radiopacity of the sealers was evaluated by radiographic analysis. Data were submitted to the two-way ANOVA and non-paired t tests at a significance level of 5%. AH Plus had the highest radiopacity (p < .05). Root canals filled with AH Plus or Bio-C had similar low percentage of voids (p > .05). There was no difference interobserver, which had similar results to those obtained with automatic segmentation for all voxel sizes evaluated (p > .05). Bio-C Sealer had appropriate filling ability. Visual and automatic segmentation can be applied to micro-CT images with voxel sizes from 5 to 20 μm to evaluate the filling of sealers with adequate radiopacity. Automatic segmentation should be used as a faster method.

show abstract

Segmentation Methods for Micro CT Images: A Comparative Study Using Human Bone Samples

Cited by 10 publications

References 7 publications

3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow

3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow

How image-processing parameters can influence the assessment of dental materials using micro-CT

Evaluation of curved root canals filled with a new bioceramic sealer: A microcomputed tomographic study using images with different voxel sizes and segmentation methods

Contact Info

Product

Resources

About