3-dimensional Reconstruction Research Articles

Posterior Reduction and Intra-Articular Cage Fusion With a C2 Nerve Root Preservation Technique for Treating Posterior Atlantoaxial Dislocation Secondary to Os Odontoideum.

Posterior C1-C2 interlaminae compression fusion with iliac bone graft may lead to donor site complications and recurrent C1 posterior dislocation for posterior atlantoaxial dislocation (AAD) secondary to os odontoideum. C1-C2 intra-articular fusion often needs C2 nerve ganglion transection to facilitate exposing and manipulating the facet joint, leading to bleeding from the venous plexus and suboccipital numbness or pain. Therefore, this study was conducted to evaluate the outcomes of posterior C1-C2 intra-articular fusion with a C2 nerve root preservation technique in the treatment of posterior AAD secondary to os odontoideum. Data of the 11 patients who underwent C1-C2 posterior intra-articular fusion because of posterior AAD secondary to os odontoideum were retrospectively reviewed. Posterior reduction was performed using C1 transarch lateral mass screws and C2 pedicle screws. Intra-articular fusion was performed using a polyetheretherketone cage filled with autologous bone from the caudal edge of the C1 posterior arch and cranial edge of the C2 laminar. Outcomes were evaluated by using the Japanese Orthopaedics Association score, Neck Disability Index, and visual analog scale for neck pain. Bone fusion was evaluated by using computed tomography and 3-dimensional reconstruction. The average follow-up duration was 43.9 ± 9.5 months. All patients achieved good reduction and bone fusion, without transection of the C2 nerve roots. The mean bone fusion time was 4.3 ± 1.1 months. There was no complication related to the surgical approach and instrumentation. Function of the spinal cord manifested by the Japanese Orthopaedics Association score significantly improved ( P < .05). The Neck Disability Index score and visual analog scale for neck pain markedly decreased (all P < .05). Posterior reduction and intra-articular cage fusion with a C2 nerve root preservation technique was a promising treatment of posterior AAD secondary to os odontoideum.

Accuracy of Femoral Tunnel Localization With Mixed Reality Technology-Assisted Single-Bundle ACL Reconstruction.

It is clinically challenging to accurately drill femoral and tibial tunnels to reconstruct the anterior cruciate ligament (ACL). Mixed reality (MR) technology, a further development of virtual reality technology, presents virtual scene information in real time and establishes an interactive feedback information loop among the real world, the virtual world, and the user. The purpose of this study was to investigate the structural and early clinical outcomes of ACL reconstruction assisted by MR technology. It was hypothesized that MR technology would improve the accuracy of tunnel localization. Cohort study; Level of evidence, 3. Included were 44 patients at a single institution who underwent arthroscopic single-bundle ACL reconstruction between June 2020 and March 2022. Reconstruction with the aid of MR technology was performed in 21 patients (MR group), and conventional arthroscopic reconstruction was performed in 23 patients. Postoperatively, the parameters related to the bone tunnel positioning were compared by computed tomography imaging with 3-dimensional (3D) reconstruction, and 12-month postoperative clinical outcomes were assessed with the Lysholm and International Knee Documentation Committee scores. There was no statistically significant difference in projection angles in the coronal, axial, or sagittal plane between the preoperative virtually created tunnel guide pin and the actual tunnel (P > .05 for all). In the MR group, the center of the femoral tunnel exit was closer to the apex of the lateral femoral condyle along the proximal-distal axis (14.07 ± 4.12 vs 17.49 ± 6.24 mm for the conventional group; P < .05) and the graft bending angle was lower (117.71° ± 8.08° vs 127.81° ± 11.91° for the conventional group; P < .05). The scatterplot of the femoral tunnel location distribution showed that the entrance and exit points in the MR group were more concentrated and closer to the ideal location of the preoperative design than in the conventional group. Patients in both groups had significant preoperative-to-postoperative improvement based on outcome scores (P < .001 for all), with no significant difference between groups. ACL reconstruction with the aid of MR technology allowed for more accurate positioning and orientation of the femoral tunnel during surgery when compared with conventional reconstruction.

Anatomy and function of the lymphatic vessels in the parietal pleura and their plasticity under inflammation in mice.

Inflammatory pleuritis often causes pleural effusions, which are drained through lymphatic vessels (lymphatics) in the parietal pleura. The distribution of button- and zipper-like endothelial junctions can identify the subtypes of lymphatics, the initial, pre-collecting, and collecting lymphatics. Vascular endothelial growth factor receptor (VEGFR)-3 and its ligands VEGF-C/D are crucial lymphangiogenic factors. Currently, in the pleura covering the chest walls, the anatomy of the lymphatics and connecting networks of blood vessels are incompletely understood. Moreover, their pathological and functional plasticity under inflammation and the effects of VEGFR inhibition are unclear. This study aimed to learn the above-unanswered questions and immunostained mouse chest walls as whole-mount specimens. Confocal microscopic images and their 3-dimensional reconstruction analyzed the vasculatures. Repeated intra-pleural cavity lipopolysaccharide challenge induced pleuritis, which was also treated with VEGFR inhibition. Levels of vascular-related factors were evaluated by quantitative real-time polymerase chain reaction. We observed the initial lymphatics in the intercostals, collecting lymphatics under the ribs, and pre-collecting lymphatics connecting both. Arteries branched into capillaries and gathered into veins from the cranial to the caudal side. Lymphatics and blood vessels were in different layers with an adjacent distribution of the lymphatic layer to the pleural cavity. Inflammatory pleuritis elevated expression levels of VEGF-C/D and angiopoietin-2, induced lymphangiogenesis and blood vessel remodeling, and disorganized the lymphatic structures and subtypes. The disorganized lymphatics showed large sheet-like structures with many branches and holes inside. Such lymphatics were abundant in zipper-like endothelial junctions with some button-like junctions. The blood vessels were tortuous and had various diameters and complex networks. Stratified layers of lymphatics and blood vessels were disorganized, with impaired drainage function. VEGFR inhibition partially maintained their structures and drainage function. These findings demonstrate anatomy and pathological changes of the vasculatures in the parietal pleura and their potential as a novel therapeutic target.

Role of MDCT neck in evaluation of neck masses: Our experience

A mass in the neck in adults is a common entity that we customarily encounter in our clinical practice. Diagnosis of these neck masses can be challenging owing to the intricate anatomy and physiology, with a myriad of presenting complaints. Neck masses can be due to multiple causes classified as congenital (eg cystic hygroma), lymphadenopathy, inflammatory or neoplastic (malignant or benign). Various imaging modalities have been applied for the evaluation such as plain x-rays, contrast studies such as lymphogram, xerography and oesophagogram etc. However, these are neither sensitive nor specific in diagnosing the aetiology of neck masses. CT being non-invasive and non-operator dependent depicts excellent quantification of tissue attenuation coefficients and is exceedingly useful in defining both the osseous and soft-tissue extent of the lesion. With the upcoming of newer generation Multidetector CT Scanners (MDCT) have made tremendous improvements in scanning time, tissue resolution and quality of three dimensional (3D) reconstructions. The aim of this study is to evaluate the role of MDCT in neck masses.

Three dimensional reconstruction and measurement of underwater spent fuel assemblies

It is an important work to measure the dimensions of underwater spent fuel assemblies in the nuclear power industry during the overhaul, to judging whether the spent fuel assemblies can continue to be used. In this paper, a three dimensional reconstruction method for underwater spent fuel assemblies of nuclear reactor based on linear structured light is proposed, and the topography and size measurement was carried out based on the reconstructed 3D model. Multiple linear structured light sensors are used to obtain contour size data, and the shape data of the whole spent fuel assembly can be collected by one-dimensional scanning motion. In this paper, we also presented a corrected model to correct the measurement error introduced by lead-glass and water is corrected. Then, we set up an underwater measurement system for spent fuel assembly based on this method. Finally, an underwater measurement experiment is carried out to verify the 3D reconstruction ability and measurement ability of the system, and the measurement error is less than ±0.05 mm.

Research on 3D reconstruction method of cattle face based on image

As the basis of intelligent breeding management and animal husbandry insurance, the identification of individual cattle is important in animal husbandry management. Given the difficulty of data acquisition caused by the non-rigid and lacking cooperation of cattle, this study proposes a method for cattle face image acquisition and processing that can efficiently adapt to the harsh environment of cattle barns. When processing the non-rigid cow face, the method of approximating the cow face to a rigid body is used to establish the cow face image data set., and the cattle face image data set is established. The Three Dimensional(3D) reconstruction method of cattle face uses a 3D image reconstruction method based on multiple perspectives. First, the scale-invariant feature transform algorithm is used to extract the image feature points. The fast library for approximate nearest neighbors algorithm is used to match feature points. The matching results are selected via random sampling consensus. Second, the structure of the motion method is used for the sparse reconstruction of point clouds, and the dense point cloud is then generated using the three-dimensional multi-view stereo vision algorithm. Finally, the Poisson surface reconstruction method is used for surface reconstruction. The results indicate that this method can effectively realize the three-dimensional reconstruction of cattle faces; the reconstructed images have obvious color, clear texture, and complete shape features.

More precise measurement of irregular splenic volume in cirrhotic patients with portal hypertension

Splenomegaly often occurs in cirrhotic patients with portal hypertension (PHT), and therefore, the efficacy and accuracy of conventional methods for measuring splenic volume are a matter of question in these patients. Here, we developed a novel approach to assess true splenic volume more precisely. High-quality thin-slice computed tomography data of 112 cirrhotic patients with PHT were obtained and reviewed. Both the conventional measurement and a novel formula obtained from 3-dimensional reconstruction software were used to estimate splenic volume, and the accuracy was compared and verified. In PHT patients, the splenic volume calculated using the conventional method was significantly less than that calculated using the 3-dimensional software. We found that the splenic volume was significantly positively correlated with splenic indices of length (L), thickness (T), and width (W) and also the diameter of the splenic vein. Using these indices, we propose 2 novel formulas using the software to estimate the splenic volume more accurately: SV = 69.686 × L + 53.077 × W + 103.525 × T + 314.510 × diameter of splenic vein −2266.209 (p < 0.01, R2 = 0.805). And a more practical simplified formula: SV' = 0.504 × L × W × Τ + 319.762 × diameter of splenic vein −81.66 (p < 0.01, R2 = 0.784). Although the conventional formula has been widely used for years, it is not suitable for an enlarged spleen. We developed 2 novel formulas for estimating splenic volume from clinical data that were more appropriate for cirrhotic patients with PHT.

Cryogenic electron ptychographic single particle analysis with wide bandwidth information transfer

Advances in cryogenic transmission electron microscopy have revolutionised the determination of many macromolecular structures at atomic or near-atomic resolution. This method is based on conventional defocused phase contrast imaging. However, it has limitations of weaker contrast for small biological molecules embedded in vitreous ice, in comparison with cryo-ptychography, which shows increased contrast. Here we report a single-particle analysis based on the use of ptychographic reconstruction data, demonstrating that three dimensional reconstructions with a wide information transfer bandwidth can be recovered by Fourier domain synthesis. Our work suggests future applications in otherwise challenging single particle analyses, including small macromolecules and heterogeneous or flexible particles. In addition structure determination in situ within cells without the requirement for protein purification and expression may be possible.

Pulmonary vein anatomy evaluated prior to atrial fibrillation ablation through multicentre electronic medical records: clinical decision support from a real-world multicentre observational study

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein (PV) isolation is a cornerstone ablation strategy in the management of patients with atrial fibrillation (AF). PV frequently display anatomical variants, which may compromise the results of cryoballoon ablation (CBA). Purpose We aimed to determine PV variation patterns in real-world patients undergoing CBA for AF and their impact on procedural success using a multicentre electronic medical records (Casiopea) sharing cardiac computed tomography (CT) scan studies performed in the referring centres and evaluated prior to the procedure in the EP reference hospital. Methods We included consecutive patients with paroxysmal or persistent AF who referred for CBA to a EP reference hospital in Spain from 2017 to 2021. All patients underwent systematic standardized CBA. Prior to the procedure, PV variation and left atrium (LA) size were evaluated in all patients by CT- scan. Blinded data were analysed by a imaging Core Lab. PV and LA anatomy were evaluated in 3-dimensional reconstructions using EnSite NavX electroanatomic mapping system. Ablation procedure was performed using either 23 or 28 mm cryoballoon according to the operator's criteria and potential predictors for AF recurrence were recorded. Results 104 patients were included (mean age 58±8 year-old, 85% male). 76 patients (73%) had recurrent paroxysmal AF, failure of antiarrhythmic drugs was present in 96% and prior radiofrequency ablation in 4%. Conventional PV anatomy consisting in 4 veins was present in 83 patients (80%), left or right common vein in 13 (13%) and accessory veins in 8 (7%). Figure. 61 patients (59%) showed left atria enlargement (&amp;gt; 40 mm or area &amp;gt; 20 cm2). CBA was performed using a 28 mm cryoballoon in 98 patients (94%). Temperature achieved during ablation was below -40°C in all the veins in 80% of the procedures. Procedural-related complications occurred in 6 patients (5%), transient phrenic nerve palsy in 2 patients and vascular damage in 4. All patients were under antiarrhythmic drugs and continued for at least 6 months after the procedure. After 19±9 months of follow-up, freedom from AF recurrence after the blanking period was 73%. Univariate analyses identified the following baseline characteristics predicted AF recurrence: prior ablation (OR = 3.6 p=0.03; 95% CI 1.1-12.3), complete PV isolation with temperature below -40°C (OR = 0.16 p = 0.001; 95% CI 0.05-0.48) and AF recurrence during the blanking period (OR = 6.3, p &amp;lt;0.001; 95% CI 2.9-13.8). PV anatomy was not a limitation nor a predictor for AF recurrences in the long-term follow-up (OR = 0.56 p = 0.17; 95% CI 0.24-1.28). Conclusion This evaluation of multicentre electronic medical records sharing CT scan studies prior CBA showed that the procedure was safe and effective with regard to the PV anatomy. The presence of anatomical variants of PV should not discourage about efficacy and it is not a limitation for CBA.

Impact of left atrial CT-angiography prior cryoballoon pulmonary vein isolation on procedural characteristics and outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Background Cryoballoon (CB) ablation for pulmonary vein isolation (PVI) is a frequently performed procedure for rhythm control therapy in atrial fibrillation (AF). However, there is limited data on the impact of preprocedural computed tomography (CT) imaging on procedural characteristics and outcomes. Purpose We aimed to determine whether the use of left atrial CT-angiography to guide CB ablation makes a difference on procedural outcomes by revealing left atrial (LA) anatomy and pulmonary vein (PV) characteristics. Methods A total of 146 AF patiens (paroxismal: 58%, age: 62 ±11 years) undergoing CB ablation were randomized for conventional PVI (control group, n=74) and PVI following preoperative CT-angiography (CTA group, n=72). In the CTA group, LA and PV anatomical features were available during the procedure using 3-dimensional reconstruction images derived from an electroanatomical mapping system. A strategy of 240-second freeze time was used for each pulmonary vein with an option for extra freeze circles until PVI was achieved. Results Procedural time (51±13 min vs. 58±21 min, p&amp;lt;0.05), LA dwell time (41±11 min vs. 47±20 min, p&amp;lt;0.05) and fluoroscopy time (9±4 min vs. 11±5 min, p&amp;lt;0.05) were significantly shorter in the control group. Fluoroscopy dose (1892.4±1319.7 cGycm2 vs. 2216.6±2371.8 cGycm2, p=0.307) and 12-month success rates (control group: 61%; CTA group: 62%, p=0.835) were comparable. No major complications were observed. Conclusions The additional information on anatomy provided by left atrial CT angiography does not manifest in improved procedural characteristics or clinical outcome. Our findings do not support the routine use of preprocedural CTA for guidance of cryoballoon ablation.

Virtual Surgical Planning for 3 Dimensional Mandibular Reconstruction With Free Fibular Osseous Flaps

Fibular vascularized osteocutaneous free flap is the gold standard for mandibular reconstruction. The traditional method is very difficult and challenging work. This technique has so far been performed solely depending on the experience of the surgeons. Recently, several software programs that can make accurate preoperative surgical plans in a three dimensional (3D)-virtual system have been developed and used to solve this problem. The aim of this study is to describe our experience and to share several tips and pitfalls of mandibular reconstruction with virtual surgical planning (VSP).

Comparative anatomy and functional implications of variation in the buccal mass in coleoid cephalopods.

In contrast to the well-studied articulated vertebrate jaws, the structure and function of cephalopod jaws remains poorly known. Cephalopod jaws are unique as the two jaw elements do not contact one another, are embedded in a muscular mass and connected through a muscle joint. Previous studies have described the anatomy of the buccal mass muscles in cephalopods and have proposed variation in muscle volume depending on beak shape. However, the general structure of the muscles has been suggested to be similar in octopuses, squids, and cuttlefish. Here we provide a quantitative analysis of the variation in the buccal mass of coleoids using traditional dissections, histological sections and contrast-enhanced computed tomography scans. Our results show that the buccal mass is composed of four main homologous muscles present in both decapodiforms and octopodiforms as suggested previously. However, we also report the presence of a muscle uniquely present in octopodiforms (the postero-lateral mandibular muscle). Our three dimensional reconstructions and quantitative analyses of the buccal mass muscles pave the way for future functional analyses allowing to better model jaw closing in coleoids. Finally, our results suggest differences in beak and muscle function that need to be validated using future in vivo functional analyses.

Three Dimensional Shape Reconstruction via Polarization Imaging and Deep Learning

Deep-learning-based polarization 3D imaging techniques, which train networks in a data-driven manner, are capable of estimating a target’s surface normal distribution under passive lighting conditions. However, existing methods have limitations in restoring target texture details and accurately estimating surface normals. Information loss can occur in the fine-textured areas of the target during the reconstruction process, which can result in inaccurate normal estimation and reduce the overall reconstruction accuracy. The proposed method enables extraction of more comprehensive information, mitigates the loss of texture information during object reconstruction, enhances the accuracy of surface normal estimation, and facilitates more comprehensive and precise reconstruction of objects. The proposed networks optimize the polarization representation input by utilizing the Stokes-vector-based parameter, in addition to separated specular and diffuse reflection components. This approach reduces the impact of background noise, extracts more relevant polarization features of the target, and provides more accurate cues for restoration of surface normals. Experiments are performed using both the DeepSfP dataset and newly collected data. The results show that the proposed model can provide more accurate surface normal estimates. Compared to the UNet architecture-based method, the mean angular error is reduced by 19%, calculation time is reduced by 62%, and the model size is reduced by 11%.

'SRISTI' (software reconstruction and implant synthesis from tomographic images); three dimensional reconstruction software for dentistry.

'SRISTI' (software reconstruction and implant synthesis from tomographic images); three dimensional reconstruction software for dentistry.

Resolution of 2 Dimensional Reconstruction of Functions with Nonsmooth Edges from Discrete Radon Transform Data

Resolution of 2 Dimensional Reconstruction of Functions with Nonsmooth Edges from Discrete Radon Transform Data

Analysis of pulmonary artery variation based on 3D reconstruction of CT angiography.

Objective: The aim of this study is to acquire pulmonary CT (Computed tomography) angiographic data for the purpose of creating a three-dimensional reconstruction. Additionally, we aim to analyze the features and deviations of the branches in both pulmonary lobes. This information is intended to serve as a more comprehensive and detailed reference for medical professionals when conducting preoperative evaluations and devising surgical plans. Method: Between August 2019 and December 2021, 420 patients were selected from the thoracic surgery department at the First Hospital of Jilin University, and underwent pulmonary 64 channel contrast enhanced CT examinations (Philips ICT 256). The images were acquired at a 1.5mm slice thickness, and the DCM files that complied with DICOM (Digital Imaging and Communications in Medicine) standards were analysed for 3D (three dimensional) reconstruction using Mimics 22.0 software. The reconstructed pulmonary artery models were assessed by attending chest surgeons and radiologists with over 10years of clinical experience. The two-dimensional image planes, as well as the coronary and sagittal planes, were utilized to evaluate the arteries. The study analyzed the characteristics and variations of the branches and courses of pulmonary arteries in each lobe of the lungs, with the exception of the subsegmental arterial system. Two chest surgeons and two radiologists with professional titles-all of whom had over a decade of clinical experience-jointly evaluated the 3D models of the pulmonary artery and similarly assessed the characteristics and variations of the branches and courses in each lobe of the lungs. Results: Significant variations were observed in the left superior pulmonary artery across the 420 subjects studied. In the left upper lobe, the blood supply of 4 arteries accounted for 50.5% (n = 212), while the blood supply of 2 arteries in the left lower lobe was the most common, accounting for 79.5% (n = 334). The greatest variation in the right pulmonary artery was observed in the branch supply of the right upper lobe mediastinal artery. In the majority of cases (77.9%), there were two arteries present, which was the most common configuration observed accounting for 64% (n = 269). In the right inferior lobe of the lung, there were typically 2-4 arteries, with 2 arteries being the most common configuration (observed in 79% of cases, n = 332). Conclusion: The three-dimensional reconstruction of pulmonary artery CT angiography enables clear observation of the branches and distribution of the pulmonary artery while also highlighting any variations. This technique holds significant clinical value for preoperative assessments regarding lesions and blood vessels.

Three dimensional seismic data reconstruction based on truncated nuclear norm

The rank reduction method is widely used to reconstruct three dimensional (3D) seismic data. The traditional multichannel singular spectrum analysis (MSSA) utilizes truncated singular value decomposition (TSVD) to approximately solve the rank function of the block Hankel structure matrix constructed by frequency slices of seismic data. However, the TSVD algorithm discards all nonzero singular values except a few largest singular values and ignores the useful seismic information in small nonzero singular values. To further utilize the seismic data information contained in these small singular values, this paper proposes a method to recover 3D seismic data with truncated nuclear norm (TNN). The proposed method imposes different constraints on large singular values and small singular values. Essentially, the TNN is closer to the rank function than the TSVD. Finally, the proposed model is addressed by the alternating direction method of multipliers, and closed-form solutions are used to update the optimization variables. The experimental results demonstrate that the proposed method achieves superior reconstruction results than the traditional MSSA method.

Morphology of the buccal apparatus of Dendronotus frondosus(Gastropoda: Nudibranchia).

Nudibranchia is the order of Gastropoda, which is known for its high diversity of dietary specializations and a diversified morphology of the buccal armature. The characters of the buccal armature are adaptive to the feeding mechanisms and diet preferences, but they also are phylogenetically informative. The morphological differences in the buccal armature imply different mechanisms of the synthesis and morphology of the formation zones. Here, we report new data on the morphology of the buccal complex in a cladobranch species with broad radula, Dendronotus frondosus, using light microscopy, transmission and scanning elctron microscopy and computer-based three- dimensional reconstruction and compare them with those on other nudibranchs. We report the presence of protective chitinous spindles in the epithelia of the oral tube and esophagus, which suggests the presence of Cnidaria in the diet of the studied mollusc species. Similar to other Cladobranchia, the jaw plate of D. frondosus is synthesized by the layer of gnathoblasts located posteriorly in the epithelial fold. Near the zone of jaw synthesis, the gnathoblasts with concentric granular endoplasmic reticulum structures were found. This may indicate the turnover of gnathoblasts during the life of a specimen. Despite that D. frondosus has a broad radula, the zone of its synthesis does not split into two parts, unlike other molluscs with broad radulae. A single radular tooth is formed by a few cells, such as in other Nudibranchia. The number of odontoblasts per tooth in D. frondosus is not defined by a tooth size. At the same time, the linear dimensions of the cells secreting radular teeth depend on the size of the teeth synthesized by them.

A straightforward and analytical method for precise X-ray CT magnification correction

X-ray Computed Tomography (XCT) has evolved over the last two decades from a medical imaging device to an industrial tool for dimensional metrology and quality control. Employing XCT for these purposes relies on the ability to generate an accurate 3D representation of the scanned object. An essential component of this is inputting the exact geometric magnification into the reconstruction algorithm, where failure to do so results in inaccurate dimensions, distortions, and/or image artifacts. Here, we propose a simple and accurate approach to correct the magnification of a rotation stage based XCT system using a single spherical reference sphere of well-known size. The method uses geometric relationships developed between the source, rotation stage, and detector to relate the sphere's position based on projection edges at three fixed locations on the rotation stage. The typical projection edge is difficult to locate as it is obscured by the air-to-object gray value gradient. Here, the precise edge locations are found through the convergence of several geometrically derived equations describing the sphere's edges from different perspectives. The results indicate that the method repeatedly delivered micron-level determination of geometric magnification, resulting in micron-level precision in dimensional reconstruction. The method is simple and easy to employ, without the need of multiple projections with a complex phantom or the use of a secondary instrument. It is simple and rapid enough to be performed on a scan-by-scan basis for any rotation stage based XCT instrument.

Defining sexual dimorphism in masculinizing chest surgery using 3-dimensional imaging

There is no consensus on the ideal scar location and inframammary fold (IMF) placement in the gender-affirming double-incision mastectomy technique. Recent advances in imaging technology have facilitated noninvasive investigations into anatomic variability, in many cases, obviating the traditional approach of cadaveric dissection to answer anatomic questions. A better understanding of chest wall sexual dimorphism may allow surgeons who perform gender-affirming procedures to achieve more natural-appearing results. A total of 60 chests were analyzed using either cadaveric dissection (n=30) or virtual dissection with 3-dimensional (3-D) reconstructions of computed tomography (CT) images (n=30) using the Vitrea® software. Chest proportions were recorded using each technique, correlating surface anatomy with muscular and bony landmarks. Cadaveric and 3-D radiography chest analysis revealed that natal male chest walls are, on average, wider and longer than natal female chest walls. The pectoralis major muscle dimensions and the location of its insertion were not found to significantly differ between male and female chests. The male nipple-areolar complex (NAC) tended to be narrower in length and width, with a less projecting nipple than the female NAC. Finally, the IMF was found to lie over the interspace between the fifth and sixth rib in both male and female chests. Our findings confirm natal male and female IMF are positioned between the 5th and 6th ribs. This fact affirms the senior author's technique of masculinizing the chest, keeping the masculinized IMF at approximately the same level as the natal female IMF and following the pectoralis major muscle edges to define the resulting scar in a way that differs from previously reported techniques.