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3D Symmetry Measure Invariant to Subject Pose During Image Acquisition.

Kawale M, Lee J, Leung SY, Fingeret MC, Reece GP, Crosby MA, Beahm EK, Markey MK, Merchant FA - Breast Cancer (Auckl) (2011)

Bottom Line: In order to quantify the effect of pose, we introduce a new measure; the 3D pBRA (Percentage Breast Retraction Assessment) index, and validate its use against the 2D pBRA index.The quantitative assessment of 3D asymmetry was found to be invariant of subject pose.Problems with pose that are inherent in 2D photographs are avoided and fiducial point identification is made easier by being able to panoramically rotate the 3D surface enabling views from any desired angle.

View Article: PubMed Central - PubMed

Affiliation: Department of Computer Science, University of Houston, Houston, Texas, USA.

ABSTRACT
In this study we evaluate the influence of subject pose during image acquisition on quantitative analysis of breast morphology. Three (3D) and two-dimensional (2D) images of the torso of 12 female subjects in two different poses; (1) hands-on-hip (HH) and (2) hands-down (HD) were obtained. In order to quantify the effect of pose, we introduce a new measure; the 3D pBRA (Percentage Breast Retraction Assessment) index, and validate its use against the 2D pBRA index. Our data suggests that the 3D pBRA index is linearly correlated with the 2D counterpart for both of the poses, and is independent of the localization of fiducial points within a tolerance limit of 7 mm. The quantitative assessment of 3D asymmetry was found to be invariant of subject pose. This study further corroborates the advantages of 3D stereophotogrammetry over 2D photography. Problems with pose that are inherent in 2D photographs are avoided and fiducial point identification is made easier by being able to panoramically rotate the 3D surface enabling views from any desired angle.

No MeSH data available.


Graphs showing linear correlation between 2D and 3D pBRA. Despite few outliers in Table 3, the data suggests high association between the 2D and 3D pBRA measures. This validates the newly introduced 3D pBRA index.
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f4-bcbcr-5-2011-131: Graphs showing linear correlation between 2D and 3D pBRA. Despite few outliers in Table 3, the data suggests high association between the 2D and 3D pBRA measures. This validates the newly introduced 3D pBRA index.

Mentions: For each subject we computed two symmetry measures for each pose, first the 3D pBRA index, and second the 2D pBRA index. Table 5 shows the results of Pearson correlation coefficient analysis between 2D pBRA and 3D pBRA for each observer and for each pose. Though we have results for two trials, we performed the 2D measurements only once since the aim of 2D measurements was to provide a reference for validation of 3D pBRA. Thus, the same 2D pBRA index was used for estimating the agreement between trial one as well as trial two measurements of the 3D pBRA index. Although for a few cases (highlighted with ‡ in Table 5), the test failed to show statistical significance (results having P-value > 0.05), for all the observers the correlation plots shown in Figure 4, clearly show linear correlation between 2D and 3D pBRA index. The positive correlation between 2D and 3D pBRA implies that the 3D pBRA index is a valid symmetry measure for stereophotogrammetry.


3D Symmetry Measure Invariant to Subject Pose During Image Acquisition.

Kawale M, Lee J, Leung SY, Fingeret MC, Reece GP, Crosby MA, Beahm EK, Markey MK, Merchant FA - Breast Cancer (Auckl) (2011)

Graphs showing linear correlation between 2D and 3D pBRA. Despite few outliers in Table 3, the data suggests high association between the 2D and 3D pBRA measures. This validates the newly introduced 3D pBRA index.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3140267&req=5

f4-bcbcr-5-2011-131: Graphs showing linear correlation between 2D and 3D pBRA. Despite few outliers in Table 3, the data suggests high association between the 2D and 3D pBRA measures. This validates the newly introduced 3D pBRA index.
Mentions: For each subject we computed two symmetry measures for each pose, first the 3D pBRA index, and second the 2D pBRA index. Table 5 shows the results of Pearson correlation coefficient analysis between 2D pBRA and 3D pBRA for each observer and for each pose. Though we have results for two trials, we performed the 2D measurements only once since the aim of 2D measurements was to provide a reference for validation of 3D pBRA. Thus, the same 2D pBRA index was used for estimating the agreement between trial one as well as trial two measurements of the 3D pBRA index. Although for a few cases (highlighted with ‡ in Table 5), the test failed to show statistical significance (results having P-value > 0.05), for all the observers the correlation plots shown in Figure 4, clearly show linear correlation between 2D and 3D pBRA index. The positive correlation between 2D and 3D pBRA implies that the 3D pBRA index is a valid symmetry measure for stereophotogrammetry.

Bottom Line: In order to quantify the effect of pose, we introduce a new measure; the 3D pBRA (Percentage Breast Retraction Assessment) index, and validate its use against the 2D pBRA index.The quantitative assessment of 3D asymmetry was found to be invariant of subject pose.Problems with pose that are inherent in 2D photographs are avoided and fiducial point identification is made easier by being able to panoramically rotate the 3D surface enabling views from any desired angle.

View Article: PubMed Central - PubMed

Affiliation: Department of Computer Science, University of Houston, Houston, Texas, USA.

ABSTRACT
In this study we evaluate the influence of subject pose during image acquisition on quantitative analysis of breast morphology. Three (3D) and two-dimensional (2D) images of the torso of 12 female subjects in two different poses; (1) hands-on-hip (HH) and (2) hands-down (HD) were obtained. In order to quantify the effect of pose, we introduce a new measure; the 3D pBRA (Percentage Breast Retraction Assessment) index, and validate its use against the 2D pBRA index. Our data suggests that the 3D pBRA index is linearly correlated with the 2D counterpart for both of the poses, and is independent of the localization of fiducial points within a tolerance limit of 7 mm. The quantitative assessment of 3D asymmetry was found to be invariant of subject pose. This study further corroborates the advantages of 3D stereophotogrammetry over 2D photography. Problems with pose that are inherent in 2D photographs are avoided and fiducial point identification is made easier by being able to panoramically rotate the 3D surface enabling views from any desired angle.

No MeSH data available.