Validation of a passive stereophotogrammetry system for imaging of the breast: a geometric analysis

Morphological Aesthetics Assessment of the Predicted 3D Simulation Results and the Actual Results of Breast Augmentation

BACKGROUND

Although three-dimensional (3D) simulations are becoming more common in preoperative breast augmentation planning, this does not necessarily imply that the simulated results are highly accurate.

OBJECTIVES

We aimed to evaluate the accuracy of the 3D simulation technique by comparing the differences in breast morphology between the 3D prediction model and the actual results.

METHODS

The simulation and actual postoperative results of 103 patients who underwent breast augmentation were analyzed retrospectively. Therefore, a 3D model was created, and the parameters of line spacing, nipple position, breast projection, surface area, and volume were evaluated. Furthermore, consider the difference in chest circumferences and breast volume.

RESULTS

In comparison with the simulation results, the actual results had a mean increase in the nipple to the inframammary fold (N-IMF) of 0.3 cm (P < 0.05) and a mean increase in basal breast width (BW) of 0.3 cm (P < 0.001), a difference that was not statistically significant in patients with larger breast volumes. There was a significant difference in the mean upper and lower breast volume distribution between simulated and actual breasts (upper pole 52.9% vs. 49.2%, P < 0.05, and lower pole 47.1% vs. 50.8%, P < 0.001). However, it was not statistically significant in patients with larger chest circumferences.

CONCLUSIONS

Our study shows that 3D simulation has uncertainties related to the patient's chest circumference and breast volume. Therefore, these two critical factors must be considered when using simulation assessment in preoperative planning.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Advances and potential of optical surface imaging in radiotherapy

This article reviews the recent advancements and future potential of optical surface imaging (OSI) in clinical applications as a four-dimensional (4D) imaging modality for surface-guided radiotherapy (SGRT), including OSI systems, clinical SGRT applications, and OSI-based clinical research. The OSI is a non-ionizing radiation imaging modality, offering real-time 3D surface imaging with a large field of view (FOV), suitable for in-room interactive patient setup, and real-time motion monitoring at any couch rotation during radiotherapy. So far, most clinical SGRT applications have focused on treating superficial breast cancer or deep-seated brain cancer in rigid anatomy, because the skin surface can serve as tumor surrogates in these two clinical scenarios, and the procedures for breast treatments in free-breathing (FB) or at deep-inspiration breath-hold (DIBH), and for cranial stereotactic radiosurgery (SRS) and radiotherapy (SRT) are well developed. When using the skin surface as a body-position surrogate, SGRT promises to replace the traditional tattoo/laser-based setup. However, this requires new SGRT procedures for all anatomical sites and new workflows from treatment simulation to delivery. SGRT studies in other anatomical sites have shown slightly higher accuracy and better performance than a tattoo/laser-based setup. In addition, radiographical image-guided radiotherapy (IGRT) is still necessary, especially for stereotactic body radiotherapy (SBRT). To go beyond the external body surface and infer an internal tumor motion, recent studies have shown the clinical potential of OSI-based spirometry to measure dynamic tidal volume as a tumor motion surrogate, and Cherenkov surface imaging to guide and assess treatment delivery. As OSI provides complete datasets of body position, deformation, and motion, it offers an opportunity to replace fiducial-based optical tracking systems. After all, SGRT has great potential for further clinical applications. In this review, OSI technology, applications, and potential are discussed since its first introduction to radiotherapy in 2005, including technical characterization, different commercial systems, and major clinical applications, including conventional SGRT on top of tattoo/laser-based alignment and new SGRT techniques attempting to replace tattoo/laser-based setup. The clinical research for OSI-based tumor tracking is reviewed, including OSI-based spirometry and OSI-guided tumor tracking models. Ongoing clinical research has created more SGRT opportunities for clinical applications beyond the current scope.

Three-Dimensional Facial Scanning at the Fingertips of Patients and Surgeons: Accuracy and Precision Testing of iPhone X Three-Dimensional Scanner

BACKGROUND

The iPhone X (Apple, Inc., Cupertino, Calif.) is the first smartphone to be released with a high-fidelity three-dimensional scanner. At present, half of all U.S. smartphone users use an iPhone. Recent data suggest that the majority of these 230 million individuals will upgrade to the iPhone X within 2 years. This represents a profound expansion in access to three-dimensional scanning technology, not only for plastic surgeons but for their patients as well. The purpose of this study was to compare the iPhone X scanner against a popular, portable three-dimensional camera used in plastic surgery (Canfield Vectra H1; Canfield Scientific, Inc., Parsippany, N.J.).

METHODS

Sixteen human subjects underwent three-dimensional facial capture with the iPhone X and Canfield Vectra H1. Results were compared using color map analysis and surface distances between key anatomical landmarks. To assess repeatability and precision of the iPhone X three-dimensional scanner, six facial scans of a single participant were obtained and compared using color map analysis. In addition, three-dimensionally-printed facial masks (n = 3) were captured with each device and compared.

RESULTS

For the experiments, average root mean square was 0.44 mm following color map analysis and 0.46 mm for surface distance between anatomical landmarks. For repeatability and precision testing, average root mean square difference following color map analysis was 0.35 mm. For the three-dimensionally-printed facial mask comparison, average root mean square difference was 0.28 mm.

CONCLUSIONS

The iPhone X offers three-dimensional scanning that is accurate and precise to within 0.5 mm when compared to a commonly used, validated, and expensive three-dimensional camera. This represents a significant reduction in the barrier to access to three-dimensional scanning technology for both patients and surgeons.

New aspects in digital breast assessment: further refinement of a method for automated digital anthropometry

Purpose

In this trial, we used a previously developed prototype software to assess aesthetic results after reconstructive surgery for congenital breast asymmetry using automated anthropometry. To prove the consensus between the manual and automatic digital measurements, we evaluated the software by comparing the manual and automatic measurements of 46 breasts.

Methods

Twenty-three patients who underwent reconstructive surgery for congenital breast asymmetry at our institution were examined and underwent 3D surface imaging. Per patient, 14 manual and 14 computer-based anthropometric measurements were obtained according to a standardized protocol. Manual and automatic measurements, as well as the previously proposed Symmetry Index (SI), were compared.

Results

The Wilcoxon signed-rank test revealed no significant differences in six of the seven measurements between the automatic and manual assessments. The SI showed robust agreement between the automatic and manual methods.

Conclusion

The present trial validates our method for digital anthropometry. Despite the discrepancy in one measurement, all remaining measurements, including the SI, showed high agreement between the manual and automatic methods. The proposed data bring us one step closer to the long-term goal of establishing robust instruments to evaluate the results of breast surgery.

Level of evidence: IV.

Stereophotogrammetric three-dimensional photography is an accurate and precise planimetric method for the clinical visualization and quantification of human papilloma virus-induced skin lesions

Background

The quantification of human papilloma virus (HPV)‐induced skin lesions is essential for the clinical assessment of the course of disease and the response to treatment. However, clinical assessments that measure dimensions of lesions using a caliper do not provide complete insight into three‐dimensional (3D) lesions, and its inter‐rater variability is often poor.

Objective

The aim of this study was to validate a stereophotogrammetric 3D camera system for the quantification of HPV‐induced lesions.

Methods

The camera system was validated for accuracy, precision and interoperator and inter‐rater variability. Subsequently, 3D photographs were quantified and compared to caliper measurements for clinical validation by Bland–Altman modelling, based on data from 80 patients with cutaneous warts (CW), 24 with anogenital warts (AGW) patients and 12 with high‐grade squamous intraepithelial lesions of the vulva (vulvar HSIL) with a total lesion count of 220 CW, 74 AGW and 31 vulvar HSIL.

Results

Technical validation showed excellent accuracy [coefficients of variation (CV) ≤ 0.68%] and reproducibility (CVs ≤ 2%), a good to excellent agreement between operators (CVs ≤ 8.7%) and a good to excellent agreement between different raters for all three lesion types (ICCs ≥ 0.86). When comparing 3D with caliper measurements, excellent biases were found for diameter of AGW (long diameter 5%), good biases were found for diameter of AGW (short diameter 10%) and height of CW (8%), and acceptable biases were found for the diameter of CW (11%) and vulvar HSIL (short diameter 14%, long diameter 16%). An unfavourable difference between these methods (bias 25%) was found for the assessment of height of AGWs.

Conclusion

Stereophotogrammetric 3D imaging is an accurate and reliable method for the clinical visualization and quantification of HPV‐induced skin lesions.

Linked Commentary: M. Skerlev et al. J Eur Acad Dermatol Venereol 2019; 33: 1445–1446. https://doi.org/10.1111/jdv.15791.

Quantifying Dynamic Deformity After Dual Plane Breast Augmentation

BACKGROUND

Dynamic breast deformity (DBD) is characterized by visible distortion and deformity of the breast due to contraction of the pectoralis major muscle after submuscular breast augmentation; fortunately, in most cases, this is not a clinically significant complaint from patients. The purpose of this study is to present a simple method for objectively measuring DBD in patients submitted to dual plane breast augmentation (DPBA).

METHODS

We studied 32 women, between 18 and 50 years old, who underwent primary DPBA with at least 1 year of follow-up. Anthropometric landmarks of the breast were marked, creating linear segments. Standardized photographs were obtained both during no pectoralis contraction (NPC) and during maximum pectoralis muscle contraction (MPC); measurements of the linear segments were taken through ImageJ imaging software, and both groups were compared.

RESULTS

We found statistically significant differences in all analyzed segments when comparing measurements of the breasts during NPC and MPC (p < 0.001).

CONCLUSION

Our study proposes a novel, standardized method for measuring DBD after DPBA. This technique is reproducible, allowing for objective quantification of the deformity in any patient, which can be valuable for both patients and surgeons, as it allows for a more thorough discussion on DBD, both pre- and postoperatively, and may help both patients and surgeons to make more informed decisions regarding potential animation deformities after breast augmentation.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

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.

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.

Comparison of three-dimensional surface-imaging systems

BACKGROUND

In recent decades, three-dimensional (3D) surface-imaging technologies have gained popularity worldwide, but because most published articles that mention them are technical, clinicians often have difficulties gaining a proper understanding of them. This article aims to provide the reader with relevant information on 3D surface-imaging systems. In it, we compare the most recent technologies to reveal their differences.

METHODS

We have accessed five international companies with the latest technologies in 3D surface-imaging systems: 3dMD, Axisthree, Canfield, Crisalix and Dimensional Imaging (Di3D; in alphabetical order). We evaluated their technical equipment, independent validation studies and corporate backgrounds.

RESULTS

The fastest capturing devices are the 3dMD and Di3D systems, capable of capturing images within 1.5 and 1 ms, respectively. All companies provide software for tissue modifications. Additionally, 3dMD, Canfield and Di3D can fuse computed tomography (CT)/cone-beam computed tomography (CBCT) images into their 3D surface-imaging data. 3dMD and Di3D provide 4D capture systems, which allow capturing the movement of a 3D surface over time. Crisalix greatly differs from the other four systems as it is purely web based and realised via cloud computing.

CONCLUSION

3D surface-imaging systems are becoming important in today's plastic surgical set-ups, taking surgeons to a new level of communication with patients, surgical planning and outcome evaluation. Technologies used in 3D surface-imaging systems and their intended field of application vary within the companies evaluated. Potential users should define their requirements and assignment of 3D surface-imaging systems in their clinical as research environment before making the final decision for purchase.