Maximilian Eder

New aspects of breast volume measurement using 3-dimensional surface imaging.

Precise and objective calculation of breast volume is helpful to evaluate the aesthetic result of breast surgery, but traditional methods are unsatisfactory. Three-dimensional (3D) scanning of the body surface allows reproducible and objective assessment of the complex breast region but requires further investigation before clinical application. The main goal of this study was to investigate the precision and accuracy of breast volume measurement using 3D body scanning. Five independent observers standardized the 3D scanning method using 2 dummy models (n = 200) and examined its applicability with 6 test subjects and 10 clinical patients (n = 2220). Breast volume measurements obtained with the 3D-scanner technology were compared with reference measurements obtained from test subjects through nuclear magnetic resonance imaging. The mean deviation of the breast volume measurements of 1 test subject by all observers, expressed as percentage of volume, was 2.86 ± 0.98, significantly higher than the deviation for the dummy models, 1.65 ± 0.42 (P < 0.001). With respect to all clinical patients, the mean measurement precision obtained preoperatively was less precise than that obtained postoperatively (3.31 ± 1.02 versus 1.66 ± 0.49, respectively). Interobserver differences in measurement precision were not statistically significant. The mean breast volumes obtained by nuclear magnetic resonance imaging (441.42 ± 137.05 mL) and 3D scanning (452.51 ± 141.88 mL) significantly correlated (r = 0.995, P < 0.001). Breast volume measurement with 3D surface imaging represents a sufficiently precise and accurate method to guarantee objective and exact recording.

Optimization of 3-dimensional imaging of the breast region with 3-dimensional laser scanners

The anatomic conditions of the female breast require imaging the breast region 3-dimensionally in a normal standing position for quality assurance and for surgery planning or surgery simulation. The goal of this work was to optimize the imaging technology for the mammary region with a 3-dimensional (3D) laser scanner, to evaluate the precision and accuracy of the method, and to allow optimum data reproducibility. Avoiding the influence of biotic factors, such as mobility, we tested the most favorable imaging technology on dummy models for scanner-related factors such as the scanner position in comparison with the torso and the number of scanners and single shots. The influence of different factors of the breast region, such as different breast shapes or premarking of anatomic landmarks, was also first investigated on dummies. The findings from the dummy models were then compared with investigations on test persons, and the accuracy of measurements on the virtual models was compared with a coincidence analysis of the manually measured values. The best precision and accuracy of breast region measurements were achieved when landmarks were marked before taking the shots and when shots at 30 degrees left and 30 degrees right, relative to the sagittal line, were taken with 2 connected scanners mounted with a +10-degree upward angle. However, the precision of the measurements on test persons was significantly lower than those measured on dummies. Our findings show that the correct settings for 3D imaging of the breast region with a laser scanner can achieve an acceptable degree of accuracy and reproducibility.

Three-dimensional evaluation of breast contour and volume changes following subpectoral augmentation mammaplasty over 6 months☆

BACKGROUND Changes in breast-morphology occur after all types of breast surgery, but a systematic and objective surgical result assessment is currently lacking. Three-dimensional (3-D) surface imaging offers the ability to quantitatively evaluate breast contour, shape, surface and volume changes after surgery. This study evaluates 3-D breast contour and volume changes after breast augmentation over time. METHODS 3-D surface imaging of 14 subpectoral breast-augmentation patients (n = 28 breasts) were accomplished over six time periods (preoperative (OP), post-OP 1: 2-3 days; post-OP 2: 1 week; post-OP 3: 1 month; post-OP 4: 3 months; and post-OP 5: 6 months after surgery) and linear-distance measurement, breast volume and surface changes were analysed. 3-D breast-contour- and volume variations are expressed in percentage changes over time. RESULTS All breast measurements changed significantly between pre-OP and post-OP 1 (Friedmann test, p = 0.001-0.025). First significant postoperative changes over time compared with post-OP 1 for breast volume, surface, sternal notch to nipple and nipple to inframammary-fold-distance measurements are quantifiable after 1 month (post hoc Wilcoxon test, p = 0.001 for all) with further relevant breast volume (post hoc Wilcoxon test, p = 0.041) and surface changes (post hoc Wilcoxon test, p = 0.037) between months 1 and 3 after surgery. The inframammary fold dropped by 1.4 cm after 6 months and final breast volume ± 0.5% is reached between months 1 and 3 after surgery. Valuable reductions in breast contour and volume by nearly 85% are also reached after 1 month (Wilcoxon test, p = 0.001) and changed to 98% after 3 months and 100% after 6 months. CONCLUSIONS Breast morphological changes following subpectoral breast augmentation are completed after 3 months. 3-D surface imaging may play a part in comparing different breast-augmentation techniques.

Objective breast symmetry evaluation using 3-D surface imaging☆

This study develops an objective breast symmetry evaluation using 3-D surface imaging (Konica-Minolta V910(®) scanner) by superimposing the mirrored left breast over the right and objectively determining the mean 3-D contour difference between the 2 breast surfaces. 3 observers analyzed the evaluation protocol precision using 2 dummy models (n = 60), 10 test subjects (n = 300), clinically tested it on 30 patients (n = 900) and compared it to established 2-D measurements on 23 breast reconstructive patients using the BCCT.core software (n = 690). Mean 3-D evaluation precision, expressed as the coefficient of variation (VC), was 3.54 ± 0.18 for all human subjects without significant intra- and inter-observer differences (p > 0.05). The 3-D breast symmetry evaluation is observer independent, significantly more precise (p < 0.001) than the BCCT.core software (VC = 6.92 ± 0.88) and may play a part in an objective surgical outcome analysis after incorporation into clinical practice.

Multiaxial mechanical properties and constitutive modeling of human adipose tissue: a basis for preoperative simulations in plastic and reconstructive surgery.

A preoperative simulation of soft tissue deformations during plastic and reconstructive surgery is desirable to support the surgeons planning and to improve surgical outcomes. The current development of constitutive adipose tissue models, for the implementation in multilayer computational frameworks for the simulation of human soft tissue deformations, has proved difficult because knowledge of the required mechanical parameters of fat tissue is limited. Therefore, for the first time, human abdominal adipose tissues were mechanically investigated by biaxial tensile and triaxial shear tests. The results of this study suggest that human abdominal adipose tissues under quasi-static and dynamic multiaxial loadings can be characterized as a nonlinear, anisotropic and viscoelastic soft biological material. The nonlinear and anisotropic features are consequences of the materials collagenous microstructure. The aligned collagenous septa observed in histological investigations causes the anisotropy of the tissue. A hyperelastic model used in this study was appropriate to represent the quasi-static multiaxial mechanical behavior of fat tissue. The constitutive parameters are intended to serve as a basis for soft tissue simulations using the finite element method, which is an apparent method for obtaining promising results in the field of plastic and reconstructive surgery.

Brustvolumenbestimmung anhand der 3-D-Oberflächengeometrie: Verifizierung der Methode mit Hilfe der Kernspintomographie / Breast volume assessment based on 3D surface geometry: verification of the method using MR imaging

Zusammenfassung Die Beurteilung von Volumen- und Formunterschieden der Brust unterliegt der subjektiven Einschätzung des Operateurs. Die 3-D-Körperoberflächenerfassung mittels 3-D-Scanner bietet eine Methode zur objektiven Brustvolumenquantifizierung, die jedoch hinsichtlich ihrer Präzision und Genauigkeit verifiziert werden muß. Die Brustvolumina von 5 Testpersonen wurden mit Hilfe eines 3-D-Oberflächenscanners bestimmt. Zur Verifizierung der 3-D-Scanergebnisse wurden Referenzvolumina mittels Kernspintomographie (MRT) erstellt. Die anatomische Thoraxwandkurvatur wurde mittels MRT-Daten segmentiert und mit der Krümmung der interpolierten hinteren Begrenzungsfläche der mittels 3-D-Scan erhobenen Brustvolumina verglichen. Die Kernspintomographie zeigte mit einer mittleren Messabweichung, gemessen in Volumenprozent, von 1,10±0,34 im Vergleich zum 3-D-Scanner mit 1,63±0,53 die bessere Messpräzision. Die mittleren Brustvolumina von MRT [rechte (linke) Brust: 638 (629)±143 (138) cm3] und 3-D-Scan [rechte (linke) Brust: 493 (497)±112 (116) cm3] korrelierten signifikant [rechte (linke) Brust: r=0,982 (0,977), p=0,003 (0,004)]. Die interpolierte Hinterwand des 3-D-Scanmodells zeigte hohe eine Übereinstimmung mit dem auf MRT-Daten basierenden tatsächlichen Verlauf der Thoraxwandkurvatur [mittlere positive (negative) Abweichung: 0,33 (-0,17)± 0,37 cm]. Die hohe Übereinstimmung und Korrelation der 3-D-Scandaten mit der MRT-basierten Verifizierung bestätigen, dass die 3-D-Scanmethode zur Brustvolumenbestimmung ausreichend präzise und genau ist. Abstract Differences in breast volume and contour are subjectively estimated by surgeons. 3D surface imaging using 3D scanners provides objective breast volume quantification, but precision and accuracy of the method requires verification. Breast volumes of five test individuals were assessed using a 3D surface scanner. Magnetic resonance imaging (MRI) reference volumes were obtained to verify and compare the 3D scan measurements. The anatomical thorax wall curvature was segmented using MRI data and compared to the interpolated curvature of the posterior breast volume delimitation of 3D scan data. MRI showed higher measurement precision, mean deviation (expressed as percentage of volume) of 1.10±0.34% compared to 1.63±0.53% for the 3D scanner. Mean MRI [right (left) breasts: 638 (629)±143 (138) cc] and 3D scan [right (left) breasts: 493 (497)±112 (116) cc] breast volumes significantly correlated [right (left) breasts: r=0.982 (0.977), p=0.003 (0.004)]. The posterior thorax wall of the 3D scan model showed high agreement with the MRI thorax wall curvature [mean positive (negative) deviation: 0.33 (-0.17)±0.37 cm]. High correspondence and correlation of 3D scan data with MRI-based verifications support 3D surface imaging as sufficiently precise and accurate for breast volume measurements.

3-D analysis of breast morphology changes after inverted T-scar and vertical-scar reduction mammaplasty over 12 months ☆

One major objective of all types of breast reduction procedures is to achieve a long-lasting, stable and aesthetically pleasing three-dimensional (3-D) breast shape, but current surgical outcome evaluation is limited. This study compares the extent of soft-tissue oedema and breast tissue migration related to 3-D breast morphology changes after inverted T-scar and vertical-scar breast reduction over 12 months. 3-D breast surface scans of patients undergoing inverted T-scar (n=52 breasts) and vertical-scar (n=44 breasts) reduction mammaplasty were obtained preoperatively and 2-3 days, 1 week, 1 month, 3 months, 6 months, 9 months and 12 months postoperatively. 3-D images were analysed at each time point comparing distances, 3-D breast contour deviations (%), breast surface (cm2) and volume (cc) measurements including volumetric distribution between the upper portion (UP) and the lower portion (LP) of the breast (%). Total postoperative breast volume decreased by 11.7% (T-scar) and by 7.8% (vertical-scar) during the first 3 months (both p<0.001) without relevant changes in the following months, indicating that soft-tissue oedema is resolved after 3 months. The T-scar (vertical-scar) group showed a preoperative UP to LP volumetric distribution of 43:57% (45:55%) versus 86:14% (91:9%) immediately after surgery. Breast tissue significantly redistributes (both p=0.001) from the UP to the LP during the first postoperative year by 16.5% (T-scar) and 21% (vertical-scar), resulting in a final UP to LP ratio of 70:30% for both techniques, without further breast contour deviations (both p>0.05) after 6 months (T-scar) and 9 months (vertical-scar). Breast morphological changes after reduction mammaplasty are completed after a period of 3-6 months in the T-scar group and 6-9 months in the vertical-scar group.

A Computational Tool for Preoperative Breast Augmentation Planning in Aesthetic Plastic Surgery

Breast augmentation was the most commonly performed cosmetic surgery procedure in 2011 in the United States. Although aesthetically pleasing surgical results can only be achieved if the correct breast implant is selected from a large variety of different prosthesis sizes and shapes available on the market, surgeons still rely on visual assessment and other subjective approaches for operative planning because of lacking objective evaluation tools. In this paper, we present the development of a software prototype for augmentation mammaplasty simulation solely based on 3-D surface scans, from which patient-specific finite-element models are generated in a semiautomatic process. The finite-element model is used to preoperatively simulate the expected breast shapes using physical soft-tissue mechanics. Our approach uses a novel mechanism based on so-called displacement templates, which, for a specific implant shape and position, describe the respective internal body forces. Due to a highly efficient numerical solver we can provide immediate visual feedback of the simulation results, and thus, the software prototype can be integrated smoothly into the medical workflow. The clinical value of the developed 3-D computational tool for aesthetic breast augmentation surgery planning is demonstrated in patient-specific use cases.

Prediction of Breast Resection Weight in Reduction Mammaplasty Based on 3-Dimensional Surface Imaging

Prediction of resection weight (RW) in reduction mammaplasty is helpful in achieving breast symmetry and in fulfilling the stringent reimbursement requirements of health insurance companies. Current breast volume estimations are largely based on surgeon’s experience, which are partially unreliable and often cumbersome to obtain. Therefore, this study aims to develop a formula to predict RW based on 3D surface imaging. A total of 68 breasts were treated with bilateral T-scar, and 40 breasts were treated with bilateral or unilateral vertical-scar reduction mammaplasty. Linear distances and volume measurements were assessed 3-dimensionally preoperatively and 6 months postoperatively. Significant correlations between the RW and the calculated preoperative breast volume (ρ = 0.804) and the sternal notch to nipple distance (ρ = 0.839) were found in both techniques (P < .001). Regression equations with the RW were performed to derive prediction formulas. Surgeons may benefit from the formulas in terms of improvement in preoperative planning, dealing with insurance coverage questions, and optimizing patient consultation.

Evaluation of Precision and Accuracy Assessment of Different 3-D Surface Imaging Systems for Biomedical Purposes

Three-dimensional (3-D) surface imaging has gained clinical acceptance, especially in the field of cranio-maxillo-facial and plastic, reconstructive, and aesthetic surgery. Six scanners based on different scanning principles (Minolta Vivid 910®, Polhemus FastSCAN™, GFM PRIMOS®, GFM TopoCAM®, Steinbichler Comet® Vario Zoom 250, 3dMD DSP 400®) were used to measure five sheep skulls of different sizes. In three areas with varying anatomical complexity (areas, 1 = high; 2 = moderate; 3 = low), 56 distances between 20 landmarks are defined on each skull. Manual measurement (MM), coordinate machine measurements (CMM) and computer tomography (CT) measurements were used to define a reference method for further precision and accuracy evaluation of different 3-D scanning systems. MM showed high correlation to CMM and CT measurements (both r = 0.987; p < 0.001) and served as the reference method. TopoCAM®, Comet® and Vivid 910® showed highest measurement precision over all areas of complexity; Vivid 910®, the Comet® and the DSP 400® demonstrated highest accuracy over all areas with Vivid 910® being most accurate in areas 1 and 3, and the DSP 400® most accurate in area 2. In accordance to the measured distance length, most 3-D devices present higher measurement precision and accuracy for large distances and lower degrees of precision and accuracy for short distances. In general, higher degrees of complexity are associated with lower 3-D assessment accuracy, suggesting that for optimal results, different types of scanners should be applied to specific clinical applications and medical problems according to their special construction designs and characteristics.