Clinical accuracy and reproducibility of Portrait 3D Surgical Simulation Platform in breast augmentation

Challenges in developing a quantitative method of measuring breast development using 3D imaging: An example of a novel method for use in induced breast development with exogenous oestrogen

OBJECTIVE

Optimal breast development is an essential part of exogenous oestrogen treatment in females undergoing pubertal induction. We set out to develop a novel technique using three-dimensional (3D) imaging to determine change in breast volume that is applicable when no pre-existing breast contours are present.

DESIGN

A prospective observational study.

PATIENTS

The imaging methodology was developed using a single male subject to assess reproducibility and validity. The technique was then applied to 29 participants undergoing pubertal induction with exogenous oestradiol who were recruited from Paediatric Gynaecology and Reproductive Endocrinology clinics at University College London Hospital.

MEASUREMENTS

Breast images were taken using a 3D photographic system. Two images, taken at different times, were manually superimposed to produce a differential breast volume. The initial step of method development set out to show that volume change was not secondary to positioning artefact or image manipulation. This was established by using images of a male participant taken on different occasions. The technique was then used to assess reproducibility in participants undergoing pubertal induction treatment.

RESULTS

Good intraobserver reproducibility (intraclass correlation (ICC) 0.77) was demonstrated with static image manipulation. Validity of the imaging technique was established as there was no significant difference between the known reference volume produced by computer generated warping and that calculated by manual image manipulation. There was excellent intraobserver reproducibility for breast volume calculation in participants undergoing induced breast development (ICC 0.99).

CONCLUSIONS

3D imaging is a promising novel tool to provide quantitative breast volume assessment in individuals undergoing breast induction with exogenous oestradiol treatment.

Nonsubjective Assessment of Shape, Volume and Symmetry during Breast Augmentation with Handheld 3D Device

Three-dimensional Surface Imaging (3DSI) has become a valuable tool for planning and documenting surgical procedures. Although surface scanners have allowed for a better understanding of breast shape, size, and asymmetry during patient consultation, its use has not been included in intraoperative assessment so far. Validation of the reliability of the intraoperative use of a portable handheld 3DSI equipment as a tool to evaluate morphological changes during breast augmentation surgery. The patients who underwent bilateral subpectoral breast augmentation through an inframammary incision were included in this study. Intraoperative 3DSI was performed with the Artec Eva device, allowing for visualization of the surgical area before incision, after use of breast sizers and implant, and after wound closure. Intraoperatively manual measurements of breast distances and volume changes due to known sizer and implant volumes were in comparison with digital measurements calculated from 3DSI of the surgical area. Bilateral breasts of 40 patients were 3D photographed before incision and after suture successfully. A further 108 implant sizer uses were digitally documented. There was no significant difference between manual tape measurement and digital breast distance measurement. Pre- to postoperative 3D volume change showed no significant difference to the known sizer and implant volume.

Use of Three-Dimensional Imaging to Assess the Effectiveness of Volume as a Critical Variable in Breast Implant Selection

BACKGROUND

In breast augmentation, breast base diameter has been recognized as an important variable in implant selection. However, breast implant volume also has a tremendous impact on the final result. Previous methods of preoperative volume determination have been limited to external devices in a bra. Computer-based three-dimensional simulation technology now allows the physician to effectively communicate with the patient preoperatively regarding volume.

METHODS

A cohort of 40 consecutive patients underwent routine breast augmentation with either anatomically shaped or round implants. Five methods of preoperative volume determination including the Crisalix three-dimensional computer imaging system (Crisalix Virtual Aesthetics, Lausanne, Switzerland), along with an associated virtual reality tool, were used to assess the preoperative desires of the patients. A postoperative questionnaire was used to assess patient satisfaction with each volume determination method.

RESULTS

Of the 40 patients, 100 percent were satisfied with their result; however, given the opportunity, 12 percent would have chosen a larger implant. The virtual reality tool and external sizers were shown to be the most effective in choosing an implant. The virtual reality tool was judged to be very helpful (62 percent), very accurate (78 percent), and important (88 percent) in helping patients choose their desired implant size.

CONCLUSION

Prioritizing volume as an implant selection variable in breast augmentation results in a very high rate of patient satisfaction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Three-dimensional simulation of aesthetic outcome from breast-conserving surgery compared with viewing photographs or standard care: randomized clinical trial

INTRODUCTION

Over half of women with surgically managed breast cancer in the UK undergo breast-conserving treatment (BCT). While photographs are shown prior to reconstructive surgery or complex oncoplastic procedures, standard practice prior to breast conservation is to simply describe the likely aesthetic changes. Patients have expressed the desire for more personalized information about likely appearance after surgery. The hypothesis was that viewing a three-dimensional (3D) simulation improves patients' confidence in knowing their likely aesthetic outcome after surgery.

METHODS

A randomized, controlled trial of 117 women planning unilateral BCT was undertaken. The randomization was three-way: standard of care (verbal description alone, control group), viewing two-dimensional (2D) photographs, or viewing a 3D simulation before surgery. The primary endpoint was the comparison between groups' median answer on a visual analogue scale (VAS) for the question administered before surgery: 'How confident are you that you know how your breasts are likely to look after treatment?'

RESULTS

The median VAS in the control group was 5.2 (i.q.r. 2.6-7.8); 8.0 (i.q.r. 5.7-8.7) for 2D photography, and 8.9 (i.q.r. 8.2-9.5) for 3D simulation. There was a significant difference between groups (P < 0.010) with post-hoc pairwise comparisons demonstrating a statistically significant difference between 3D simulation and both standard care and viewing 2D photographs (P < 0.010 and P = 0.012, respectively).

CONCLUSION

This RCT has demonstrated that women who viewed an individualized 3D simulation of likely aesthetic outcome for BCT were more confident going into surgery than those who received standard care or who were shown 2D photographs of other women. The impact on longer-term satisfaction with outcome remains to be determined.Registration number: NCT03250260 (http://www.clinicaltrials.gov).

Measuring Differential Volume Using the Subtraction Tool for Three-Dimensional Breast Volumetry: A Proof of Concept Study

Background. Three-dimensional (3D) photography provides a promising means of breast volumetry. Sources of error using a single-captured surface to calculate breast volume include inaccurate designation of breast boundaries and prediction of the invisible chest wall generated by computer software. An alternative approach is to measure differential volume using subtraction of 2 captured surfaces. Objectives. To explore 3D breast volumetry using the subtraction of superimposed images to calculate differential volume. To assess optimal patient positioning for accurate volumetric assessment. Methods. Known volumes of breast enhancers simulated volumetric changes to the breast (n = 12). 3D photographs were taken (3dMDtorso) with the subject positioned upright at 90° and posteriorly inclined at 30°. Patient position, breathing, distance and camera calibration were standardised. Volumetric analysis was performed using 3dMDvultus software. Results. A statistically significant difference was found between actual volume and measured volumes with subjects positioned at 90° (P < .05). No statistical difference was found at 30° (P = .078), but subsequent Bland–Altman analysis showed evidence of proportional bias (P < .05). There was good correlation between measured and actual volumes in both positions (r = .77 and r = .85, respectively). Univariate analyses showed breast enhancer volumes of 195 mL and 295 mL to incur bias. The coefficient of variation was 5.76% for single observer analysis. Conclusion. Positioning the subject at a 30° posterior incline provides more accurate results from better exposure of the inferior breast. The subtraction tool is a novel method of measuring differential volume. Future studies should explore methodology for application into the clinical setting.

Satisfaction with cosmetic outcomes of breast reconstruction: Investigations into the correlation between the patients' Breast-Q outcome and the judgment of panels

Objectives

We aimed to determine the relation between breast reconstruction method, patient satisfaction, and surgeon reported cosmetic outcome among women who underwent breast reconstruction after mastectomy.

Study Design

A cross-sectional study of patients treated between 2006 and 2010.

Main Outcome

Women's satisfaction with cosmetic outcomes after breast reconstruction.

Measures

Cosmetic outcomes were evaluated by (1) women using the Breast-Q to rate satisfaction with breasts outcomes, and (2) an independent panel using the Strasser score. The relationships between the Breast-Q rating, Strasser scores, and breast reconstruction methods, including laterality and timing, were evaluated by Mann–Whitney U tests, Spearman's rank correlations, and Wilcoxon signed-rank tests.

Results

Ninety-four women were included. Patients were more satisfied with their breasts if they had undergone autologous, unilateral, or secondary breast reconstruction compared with those who underwent alloplastic, bilateral, or primary breast reconstruction (p-values 0.008, 0.011, and 0.001, respectively). The Strasser system did not reveal significant cosmetic differences, with all breast reconstructions graded as mediocre or poor.

Conclusions

Patient satisfaction with breast outcomes, as measured by the Breast-Q, was described as mediocre or poorly reflected by the Strasser score. If doctors are to support patients to make informed decisions on the optimal method of breast reconstruction, we need a more sensitive, comprehensive tool reflecting patients’ cosmetic outcomes.

New software and breast boundary landmarks to calculate breast volumes from 3D surface images

Background

A method to accurately calculate breast volumes helps achieving a better breast surgery outcome. 3D surface imaging potentially allows these calculations in a harmless, quick, and practicable way. The calculated volume from a 3D surface image is dependent on the determined breast boundary and the method of chest wall simulation by software. Currently, there is no consensus on a robust set of breast boundary landmarks and validation studies on breast volume calculation software are scarce. The purposes of this study were to determine the robustness of newly introduced breast boundary landmarks and introduce and validate a new method to simulate a chest wall.

Methods

Sixteen subjects who underwent a unilateral simple mastectomy were included. In addition to the natural skin fold of the breast, the sternomanubrial joint, the transition of the pectoral muscle curve into the breast curvature, and the midaxillary line were used as landmarks to indicate the breast boundary. The intra- and interrater variability of these landmarks was tested. Furthermore, new chest wall simulation software was validated on the breastless chest side of the subjects.

Results

The intra- and interrater variability of the three breast boundary markers was small (mean 3.5–6.7 mm), and no significant difference was found between the intra- and interrater variability (p = 0.08, p = 0.06, and p = 0.10). The mean volume error of the most accurately simulated chest wall was 4.6 ± 37 ml.

Conclusion

The newly introduced landmarks showed to be robust and our new chest wall simulation algorithm showed accurate results.

Level of Evidence: Level IV, diagnostic study.

Validation of the Vectra XT three-dimensional imaging system for measuring breast volume and symmetry following oncological reconstruction

PURPOSE

Three-dimensional surface imaging (3D-SI) of the breasts enables the measurement of breast volume and shape symmetry. If these measurements were sufficiently accurate and repeatable, they could be used in planning oncological breast surgery and as an objective measure of aesthetic outcome. The aim of this study was to validate the measurements of breast volume and symmetry provided by the Vectra XT imaging system.

METHODS

To validate measurements, breast phantom models of true volume between 100 and 1000 cm3 were constructed and varying amounts removed to mimic breast tissue 'resections'. The volumes of the phantoms were measured using 3D-SI by two observers and compared to a gold standard. For intra-observer repeatability and inter-observer reproducibility in vivo, 16 patients who had undergone oncological breast surgery had breast volume and symmetry measured three times by two observers.

RESULTS

A mean relative difference of 2.17 and 2.28% for observer 1 and 2 respectively was seen in the phantom measurements compared to the gold standard (n = 45, Bland Altman agreement). Intra-observer variation over ten repeated measurements demonstrated mean coefficients of variation (CV) of 0.58 and 0.49%, respectively. The inter-observer variation demonstrated a mean relative difference of 0.11% between the two observers. In patients, intra-observer variation over three repeated volume measurements for each observer was 3.9 and 3.8% (mean CV); the mean relative difference between observers was 5.78%. For three repeated shape symmetry measurements using RMS projection difference between the two breasts, the intra-observer variations were 8 and 14% (mean CV), the mean relative difference between observers was 0.43 mm for average symmetry values that ranged from about 3.5 to 15.5 mm.

CONCLUSION

This first validation of breast volume and shape symmetry measurements using the Vectra XT 3D-SI system suggests that these measurements have the potential to assist in pre-operative planning and also as a measure of aesthetic outcome.

Three-Dimensional Imaging and Breast Measurements: How Predictable Are We?

BACKGROUND

Outcomes in aesthetic breast surgery are dependent on preoperative breast measurements. The accuracy of 3-dimensional (3D) imaging in measuring critical landmarks in augmentation mammaplasty surgery has not been described.

OBJECTIVES

We aimed to determine the predictability of 3D imaging compared to direct measurements.

METHODS

Two raters measured the breasts of 28 women using four anthropometric (direct) measurements: sternal notch to nipple distance (Sn-N), nipple to midline (N-M), nipple to inframammary-fold distance under maximal stretch (N-IMF), and base width (BW). Measurements (indirect) were also obtained using 3D imaging. Statistical analysis was completed with Bland-Altman plots.

RESULTS

Each rater collected 56 data points for each of the four measurements. This resulted in 224 data points per rater. The Sn-N measurement had a 0.05 cm (SD, 0.65) difference in the mean values obtained between direct and indirect measurements. N-M had a mean difference of 0.20 cm (SD, 0.62). The mean difference for BW was 1.26 cm (SD, 0.69 cm), and N-IMF showed a mean difference of 1.22 cm (SD, 0.74 cm). Three-dimensional imaging overestimated Sn-N, N-M, and BW, while it underestimated N-IMF.

CONCLUSIONS

Three-dimensional imaging has good utility and is most accurate for Sn-N and N-M measurements, which require frontal imaging of a standing patient. BW and N-IMF are less accurate due to obscured landmarks on frontal imaging. The medial and lateral aspects of the breast may be obscured when measuring BW on 3D imaging, which may explain this difference. N-IMF is a dynamic measurement, and as a result, 3D imaging has limited ability to measure this distance accurately.

LEVEL OF EVIDENCE 3

Enhancing breast projection in autologous reconstruction using the St Andrew's coning technique and 3D volumetric analysis

Background

An increasing number of women undergo mastectomy for breast cancer and post-mastectomy autologous breast reconstruction has been shown to significantly improve the psychosexual wellbeing of the patients. A goal of treatment is to achieve symmetry and projection to match the native breast, and/or the contralateral breast in the case of a unilateral reconstruction. Autologous reconstruction, particularly with the deep inferior epigastric artery perforator (DIEP) flap, is particularly advantageous as it can be manipulated to mimic the shape and turgor of the native breast. However, very few techniques of shaping the breast conus when insetting the DIEP flap to enhance aesthetic outcome have been reported to date. With the aide of three-dimension (3D) photography and 3D-printed mirrored image of the contralateral breast as a guide intraoperatively, we describe our St Andrew's coning technique to create a personalized flap projection.

Method

We report a prospective case series of 3 delayed unilateral breast reconstructions where symmetrization procedure to the contralateral breast was not indicated. Using a commercial 3D scanner (VECTRA XR, Canfield Scientific), the breast region was imaged. The mirrored image was 3D-printed in-house using a desktop 3D printer.

Results

In all cases, projection of the breast mound was able to be safely achieved, with a demonstrated central volume (or 'cone') able to be highlighted on imaging and a 3D printed breast. A 3D print of the contralateral breast was able to be used intraoperatively to guide the operative approach.

Conclusions

The St Andrew's coning technique is a useful aesthetic maneuver for achieving breast projection during DIEP flap breast reconstruction, with 3D imaging techniques able to assist in perioperative assessment of breast volume.

Preoperative implant selection for unilateral breast reconstruction using 3D imaging with the Microsoft Kinect sensor

AIMS

This study aimed to investigate whether breast volume measured preoperatively using a Kinect 3D sensor could be used to determine the most appropriate implant size for reconstruction.

METHODS

Ten patients underwent 3D imaging before and after unilateral implant-based reconstruction. Imaging used seven configurations, varying patient pose and Kinect location, which were compared regarding suitability for volume measurement. Four methods of defining the breast boundary for automated volume calculation were compared, and repeatability assessed over five repetitions.

RESULTS

The most repeatable breast boundary annotation used an ellipse to track the inframammary fold and a plane describing the chest wall (coefficient of repeatability: 70 ml). The most reproducible imaging position comparing pre- and postoperative volume measurement of the healthy breast was achieved for the sitting patient with elevated arms and Kinect centrally positioned (coefficient of repeatability: 141 ml). Optimal implant volume was calculated by correcting used implant volume by the observed postoperative asymmetry. It was possible to predict implant size using a linear model derived from preoperative volume measurement of the healthy breast (coefficient of determination R² = 0.78, standard error of prediction 120 ml). Mastectomy specimen weight and experienced surgeons' choice showed similar predictive ability (both: R² = 0.74, standard error: 141/142 ml). A leave one-out validation showed that in 61% of cases, 3D imaging could predict implant volume to within 10%; however for 17% of cases it was >30%.

CONCLUSION

This technology has the potential to facilitate reconstruction surgery planning and implant procurement to maximise symmetry after unilateral reconstruction.

The accuracy of breast volume measurement methods: A systematic review

Breast volume is a key metric in breast surgery and there are a number of different methods which measure it. However, a lack of knowledge regarding a method's accuracy and comparability has made it difficult to establish a clinical standard. We have performed a systematic review of the literature to examine the various techniques for measurement of breast volume and to assess their accuracy and usefulness in clinical practice. Each of the fifteen studies we identified had more than ten live participants and assessed volume measurement accuracy using a gold-standard based on the volume, or mass, of a mastectomy specimen. Many of the studies from this review report large (>200 ml) uncertainty in breast volume and many fail to assess measurement accuracy using appropriate statistical tools. Of the methods assessed, MRI scanning consistently demonstrated the highest accuracy with three studies reporting errors lower than 10% for small (250 ml), medium (500 ml) and large (1000 ml) breasts. However, as a high-cost, non-routine assessment other methods may be more appropriate.

Breast volumetric analysis for aesthetic planning in breast reconstruction: a literature review of techniques

BACKGROUND

Accurate volumetric analysis is an essential component of preoperative planning in both reconstructive and aesthetic breast procedures towards achieving symmetrization and patient-satisfactory outcome. Numerous comparative studies and reviews of individual techniques have been reported. However, a unifying review of all techniques comparing their accuracy, reliability, and practicality has been lacking.

METHODS

A review of the published English literature dating from 1950 to 2015 using databases, such as PubMed, Medline, Web of Science, and EMBASE, was undertaken.

RESULTS

Since Bouman's first description of water displacement method, a range of volumetric assessment techniques have been described: thermoplastic casting, direct anthropomorphic measurement, two-dimensional (2D) imaging, and computed tomography (CT)/magnetic resonance imaging (MRI) scans. However, most have been unreliable, difficult to execute and demonstrate limited practicability. Introduction of 3D surface imaging has revolutionized the field due to its ease of use, fast speed, accuracy, and reliability. However, its widespread use has been limited by its high cost and lack of high level of evidence. Recent developments have unveiled the first web-based 3D surface imaging program, 4D imaging, and 3D printing.

CONCLUSIONS

Despite its importance, an accurate, reliable, and simple breast volumetric analysis tool has been elusive until the introduction of 3D surface imaging technology. However, its high cost has limited its wide usage. Novel adjunct technologies, such as web-based 3D surface imaging program, 4D imaging, and 3D printing, appear promising.

Anthropometric Measurements Usage in Medical Sciences

Morphometry is introduced as quantitative approach to seek information concerning variations and changes in the forms of organisms that described the relationship between the human body and disease. Scientists of all civilization, who existed until today, examined the human body using anthropometric methods. For these reasons, anthropometric data are used in many contexts to screen for or monitor disease. Anthropometry, a branch of morphometry, is the study of the size and shape of the components of biological forms and their variations in populations. Morphometrics can also be defined as the quantitative analysis of biological forms. The field has developed rapidly over the last two decades to the extent that we now distinguish between traditional morphometrics and the more recent geometric morphometrics. Advances in imaging technology have resulted in the protection of a greater amount of morphological information and have permitted the analysis of this information. The oldest and most commonly used of these methods is radiography. With developments in this area, CT and MRI have also been started to be used in screening of the internal organs. Morphometric measurements that are used in medicine, are widely used in the diagnosis and the follow-up and the treatment of the disease, today. In addition, in cosmetology use of these new measurements is increasing every day.

3D surface imaging of the human female torso in upright to supine positions

Three-dimensional (3D) surface imaging of breasts is usually done with the patient in an upright position, which does not permit comparison of changes in breast morphology with changes in position of the torso. In theory, these limitations may be eliminated if the 3D camera system could remain fixed relative to the woman’s torso as she is tilted from 0 to 90 degrees. We mounted a 3dMDtorso imaging system onto a bariatric tilt table to image breasts at different tilt angles. The images were validated using a rigid plastic mannequin and the metrics compared to breast metrics obtained from 5 subjects with diverse morphology. The differences between distances between the same fiducial marks differed between the supine and upright positions by less than one percent for the mannequin, whereas the differences for distances between the same fiducial marks on the breasts of the 5 subjects differed significantly and could be correlated with body mass index and brassiere cup size for each position change. We show that a tilt table - 3D imaging system can be used to determine quantitative changes in the morphology of ptotic breasts when the subject is tilted to various angles.

Achieving Symmetry in Unilateral DIEP Flap Breast Reconstruction: An Analysis of 126 Cases over 3 Years

Many patients who prefer breast reconstruction by a deep inferior epigastric artery perforator (DIEP) flap often lack skin laxity at the lower abdomen. Recreating a symmetrical breast with various degrees of ptosis is one of the most difficult procedures. In this report, varied DIEP flap shapes were precisely designed on the basis of normal breast ptosis. The reconstructive outcomes were quantitatively evaluated for asymmetry of footprint, volume, breast projection, and nipple position by a 3-dimensional scanning system. One hundred twenty-six cases of unilateral DIEP flap breast reconstruction were successfully performed from January 2009 to July 2012. The maximal flap width ranged from 7.5 to 10.5 cm (mean, 9.0 cm), and the flap length ranged from 28 to 38 cm (mean, 32.5 cm). The discrepancy of the footprint and nipple position did not differ significantly between the reconstructed and normal breasts. However, the reconstructed side had significantly higher breast volume and projection. For patients with a relatively tight abdomen, the flap design and shaping approach we propose achieves a maximal symmetrical outcome and should be considered as a good and reliable option.

Three-Dimensional Imaging for Breast Augmentation: Is This Technology Providing Accurate Simulations?

BACKGROUND

For patients considering breast augmentation, 3-dimensional (3D) imaging provides a preoperative simulation of the postoperative result. However, the clinical accuracy of these simulations has not been assessed.

OBJECTIVE

The authors compared preoperative simulations with postoperative results of breast augmentation to permit more informed decisions about breast augmentation.

METHODS

To determine differences between simulations and actual results, volumetric and contour analyses were performed for patients who underwent 3D imaging both preoperatively and 3 months after breast augmentation. All patients received round smooth silicone implants or anatomically shaped cohesive silicone gel implants; the mean volume was 295 cc.

RESULTS

Twenty patients (40 breasts) underwent 3D imaging both pre- and postoperatively. There were no procedural complications or revisions. The mean difference between preoperative simulation and postoperative breast volume was 27.2 cc (range, 1.4-99.5 cc), representing a 9.2% mean difference in volume and an accuracy of 90.8%. The mean absolute difference (root mean square) of all surface points along the breast in aggregate was 4.0 mm (range, 1.8-8.3 mm). No specific location along the surface contour of the breast could be identified as having the greatest differences.

CONCLUSIONS

The preoperative simulation provided by 3D imaging is >90% accurate in predicting postoperative breast volume. The mean absolute differential for surface contour in this study was 4 mm, representing 98.4% accuracy based on average surface area.

LEVEL OF EVIDENCE

3.