Assessment Tools for Breast Surgery Based on 3D
Surface Anatomy Imaging
Beattie S, Siebert JP, Stevenson* JH & Yap* LH
The 3D-MATIC Laboratory – Department of Computing Science, University of Glasgow,
Glasgow, Scotland G12 8NN
* Specialist Services Group, Ninewells Hospital, Dundee, Scotland DD1 9SY
psiebert@dcs.gla.ac.uk
Abstract. The authors present the results of a pilot investigation into the use of
stereo-photogrammetry for capturing the 3D surface anatomy of the living
breast to allow non-contact volumetric assessment for surgery planning
purposes. Breast volume measurement is investigated in terms of chest wallbreast segmentation methods, inter and intra operator variability and pose.
1. Introduction
Techniques for 3D imaging the surface anatomy of the breast have become
sufficiently mature to allow their investigation for assessment of key breast
parameters prior to and following surgery. Clinically relevant parameters, such as
breast surface area, volume and symmetry, can be computed in order to assist the
selection of a particular surgery protocol and aid the assessment of the surgical
outcome. This paper reports a pilot investigation1 to gain an initial understanding of
measurement errors and repeatability associated with this technique.
2. 3D Data Capture and Analysis
Subjects are imaged in 3D using the C3D [1] stereo-photogrammetry system
originally developed by the Turing Institute, Glasgow. Software-based measurement
tools [2] under development at 3D-MATIC, are then used to segment and analyse the
breast region within the captured 3D surface anatomy data. Three different interactive
breast segmentation methods have been evaluated: manual delineation, Coons patch
[3] and cubic spline [4]. Each segmentation method estimates the chest wall
underlying the breast based on the morphology of the chest area surrounding the
breast region. The best approximation method will result in a surface patch which
closely resembles the morphology of the physical chest wall and which can be
reproduced accurately and reliably.
Additional facilities [5], originally developed for 3D facial measurement, have
been adapted to allow longitudinally captured 3D images of breasts to be registered
and their volume differences to be estimated. A similar procedure has been adopted to
estimate the area and volume difference between breasts captured simultaneously
based on the computation of a symmetry plane.
3. Phantom Breast Initial Results
In order to assess the volumetric accuracy of breast scans, three plasticine breast
models of differing size were constructed and 3D imaged against a flat surface using
the simplest approximation method, the centroid method. The volume of each
plasticine model was then measured using water displacement, Table 1.
Table 1. Volumetric comparisons of phantom breasts
Volume (cm3)
Test Model
Application
Water
Difference
Displacement
Model 1
Model 2
Model 3
540.30
589.23
812.11
535
590
800
5.3
0.77
12.11
Average % Error
% Error
0.99
0.13
1.51
0.88
4. Real Breast Initial Results
Five breast reduction volunteers were recruited and imaged using C3D. Their
breast volume was then evaluated in terms of intra-operator variability (Tables 2 & 3),
inter-operator variability (Table 4), method of segmentation (Tables 2-4) and
reliability of measurement with regard to posture (Table 5, Coons method).
Table 2. Volume variability over 5 segmentation trials, same subject & operator
Volume (cm3)
Patch Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Mean
Std Dev
method
Centroid 615.22 595.16 638.45 659.15 624.68 626.53 24.1
539.13 527.01 544.04 526.44 528.82 533.08 8.00
Coons
519.34 524.09 510.52 494.95 538.94 517.56 16.31
Spline
Table 3. Volume variability for three subjects, five trials each, same operator
Subject 1
Subject 2
Subject 3
Volume (cm3)
Subject
Mean
Std Dev Mean
Std Dev Mean
Std Dev
626.532 24.09132 758.19 27.97834 637.738 17.70348
Centroid
533.088 7.996966 630.062 10.15626 525.05 9.004921
Coons
517.568 16.30711 626.296 18.27934 526.382 14.38113
Spline
Table 4. Volume variability for three operators, five trials each, same subject
Operator 1
Operator 2
Operator 3
Volume (cm3)
Patch
Mean
Std Dev Mean
Std Dev Mean
Std Dev
method
624.7
24.1
632.46 19.6
571.79
20.11
Centroid
533.09 8
520.9
10.37
520.292 8.79
Coons
517.56 16.3
501.67 17.1
499.03
16.89
Spline
Table 5. Volume variability with different postures, same subject & operator
Volume(cm3) Coons Segmentation Method
Posture Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Mean
Std Dev.
Arms down 440.1
448.4 433.38 451.61 439.01 459.68 7.39
Arms out
498.9
498.1 492.25 505.21 507.3 496.41 6.01
Arms up
515.91 520.06 516.58 520.3 513.61 517.51 2.85
5. Conclusions
The principal findings are that the reported method is capable of estimating the
volume of phantom targets to better than a few percent error. Based on the volunteer
3D data, both the intra and inter operator volume measurement standard deviations for
the Coons patch segmentation method were approximately twice as low as those of
the other methods investigated. The standard “arms raised” posture appeared to be
significantly more repeatable compared to “arms lowered” and “arms out stretched”
postures (segmented using the Coons method).
6. References
1. Siebert, J.P., Marshall, S.J.: Human Body 3D Imaging by Speckle Texture Projection
Photogrammetry. Sensor Review, Vol. 20 No. 3, 218-226 (2000)
2. Moffat, A.M.: A Prototype Breast Surgery Planning and Assessment Tool. MSc Dissertation
in Information Technology. Department of Computing Science, University of Glasgow,
Glasgow (1999)
3. Fletcher, Y., McAllister, D.F.: A Tension Compatible Patch for Shape-Preserving Surface
Interpolation. IEEE Computer Graphics, Vol. 9 No. 3, 45-55 (1989)
4. Knott, G.D.: Interpolating Cubic Splines. Birkhauser Boston, Cambridge MA (1999)
5. Mao, Z., Siebert, P. and Ayoub, A.: Development of 3D Measuring Techniques for the
Analysis of Facial Soft Tissue Change. MICCAI 2000, 3rd International Conference on
Medical Image Computing Computer Assisted Intervention. Pittsburgh USA 1051-1060
(2000)
1
Funding support from NHS Tayside and EPSRC (Faraday Partnership scheme).