Search Results (76)

Accurate spleen segmentation in abdominal CT scans remains a critical challenge in medical image analysis due to variable morphology, low tissue contrast, and proximity to similar anatomical structures. This paper presents an enhanced U-Net architecture that addresses these challenges through multi-slice contextual integration and interpretable deep learning. Our approach incorporates three-channel inputs from adjacent CT slices, implements a hybrid loss function combining Dice and binary cross-entropy terms, and integrates Grad-CAM visualization for enhanced model interpretability. Comprehensive evaluation on the Medical Decathlon dataset demonstrates superior performance, with a Dice similarity coefficient of 0.923 ± 0.04, outperforming standard 2D approaches by 3.2%. The model exhibits robust performance across varying slice thicknesses, contrast phases, and pathological conditions. Grad-CAM analysis reveals focused attention on spleen–tissue interfaces and internal vascular structures, providing clinical insight into model decision-making. The system demonstrates practical applicability for automated splenic volumetry, trauma assessment, and surgical planning, with processing times suitable for clinical workflow integration. Full article

Diabetic retinopathy (DR) is a major source of retinal disease and vision loss worldwide. Current treatments fail to address the loss of neurons and are associated with significant side effects. Here, we investigated whether retinal progenitor cells (RPCs) could improve anatomic and functional outcomes in a rat model of DR. Male Long Evans (LE) rats were given streptozotocin (STZ), and the induction of diabetes was confirmed prior to the intravitreal injection of RPCs, either allogeneic (no immunosuppression) or human (with cyclosporin A), at 1 week post-induction. Animals were tested at 6 weeks post-induction via electroretinogram (ERG), optomotor response (OR), and contrast sensitivity (CS). Retinas were harvested post-mortem, 8 weeks post-STZ induction, and analyzed using immunohistochemistry (IHC). In rat RPC-treated eyes, ERG (b-wave, oscillatory potentials), OR, and CS all showed a positive effect for cell treatment versus controls. IHC showed a markedly diminished extravasation of albumin, a decreased VEGF expression, and an improved morphology in cellular and synaptic layers. Human RPC-treated eyes replicated a subset of these results. Together, this provides evidence of both anatomic and functional treatment effects in a rat model of DR, encompassing retinal neuroprotection as well as improved vascular integrity, thereby supporting the further investigation of intravitreal RPCs for the treatment of this condition. Full article

Background: Three-dimensional (3D) printing technology has rapidly emerged as a transformative tool in medicine, enabling the conversion of two-dimensional scans into highly accurate 3D models. This technology, especially when combined with artificial intelligence (AI) and advanced materials, offers numerous applications in surgical planning, simulation-based training, and patient-specific care. Methods: This review examines current literature and case studies on the use of 3D printing technology in various fields of medicine, especially in surgical specialties. Key applications include surgical planning, mock surgeries, biopsy guide creation, and customized implant fabrication across various surgical fields. Results: 3D printing is transforming surgery by enabling precise visualization of tumors and critical structures, significantly enhancing preoperative planning for conditions such as bone, soft tissue (e.g., neuroblastomas), renal, and maxillofacial tumors. In reconstruction surgeries, patient-specific 3D-printed implants ensure better anatomical compatibility, particularly in maxillofacial, neurosurgical, and vascular applications. Puncture guides improve procedural accuracy in interventions like percutaneous nephrolithotripsy. Detailed anatomical models aid in simulation-based training, increasing preparedness for complex procedures. Additionally, patient-specific implants and AI-integrated decision support systems are paving the way for more personalized and efficient surgical care. Conclusions: 3D printing technology, especially when combined with AI, is reshaping modern surgery by improving both accuracy, safety, and personalized healthcare. Its applications extend across multiple specialties, offering new possibilities in surgical planning, training, and patient-specific treatments. As AI and bioprinting continue to evolve, the potential for real-time applications, such as live-printed tissue implants and enhanced decision support, could drive the next phase of innovation in various fields. Full article

This study describes the design and validation of an experimental setup for testing photoplethysmographic (PPG) devices intended for the non-invasive monitoring of vascular accesses in hemodialysis patients. Continuous assessment of arteriovenous fistulas is essential to detect pathological conditions such as stenosis, which can compromise patient safety and dialysis efficacy. While PPG-based sensors are capable of detecting such anomalies, their clinical applicability must be supported by controlled in vitro validation. The developed system replicates the anatomical, mechanical, optical, and hemodynamic features of vascular accesses. A 3D fistula model was designed and fabricated via 3D printing and silicone casting. The hydraulic circuit used red India ink and a PWM-controlled pump to simulate physiological blood flow, including stenotic conditions. Quantitative validation confirmed anatomical accuracy within 0.1 mm tolerance. The phantom exhibited an average Shore A hardness of 20.3 ± 1.1, a Young’s modulus of 10.4 ± 0.9 MPa, and a compression modulus of 105 MPa—values consistent with soft tissue behavior. Burst pressure exceeded 2000 mmHg, meeting ISO 7198:2016 standards. Flow rates (400–700 mL/min) showed <1% error. Compliance was 2.4 ± 0.2, and simulated blood viscosity was 3.9 ± 0.3 mPa·s. Systolic and diastolic pressures fell within physiological ranges. Photoplethysmographic signals acquired using a MAX30102 sensor (Analog devices Inc., Wilmington, MA, USA) reproduced key components of in vivo waveforms, confirming the system’s suitability for device testing. Full article

Three-dimensional (3D) modeling and printing technologies are increasingly used in pediatric surgery, offering improved anatomical visualization, surgical planning, and personalized approaches to complex conditions. Compared to standard imaging, patient-specific 3D models—virtual or printed—provide a more intuitive spatial understanding of congenital anomalies, tumors, and vascular anomalies. This review compiles evidence from pediatric surgical fields including oncology, abdominal, and thoracic surgery, highlighting the clinical relevance of 3D applications. The technological workflow—from image segmentation to computer-aided design (CAD) modeling and multimaterial printing—is described, emphasizing accuracy, reproducibility, and integration into hospital systems. Several clinical cases are presented: neuroblastoma, cloacal malformation, conjoined twins, and two cases of congenital diaphragmatic hernia (one with congenital pulmonary airway malformation, CPAM). In each, 3D modeling enhanced anatomical clarity, increased surgeon confidence, and supported safer intraoperative decision-making. Models also improved communication with families and enabled effective multidisciplinary planning. Despite these advantages, challenges remain, such as production time, cost variability, and lack of standardization. Future directions include artificial intelligence-based automation, expanded use of virtual and mixed reality, and prospective validation studies in pediatric cohorts. Overall, 3D modeling represents a significant advance in pediatric precision surgery, with growing evidence supporting its safety, clinical utility, and educational value. Full article

Background/Objectives: Gastric cancer remains a leading cause of cancer-related mortality, with over 50% of cases diagnosed at a locally advanced or metastatic stage. High-quality surgical resection within the embryological mesogastric layer is critical for achieving optimal oncological outcomes but is often complicated by anatomical distortion in advanced tumors. This study aimed to develop and validate a system of topographic and anatomical navigation landmarks for embryologically guided laparoscopic gastrectomy, leveraging 3D modeling to enhance precision and safety. Methods: A single-center study was conducted, analyzing 78 patients undergoing emergency laparoscopic gastrectomy for locally advanced gastric cancer. Preoperative 3D models were generated from CT data annotations to map the stomach, tumor, vascular structures, and mesogastric adipose tissue. Thirty biomodels were used to refine dissection techniques. Surgical procedures adhered to embryological principles, with lymphadenectomy guided by predefined landmarks. Histopathological validation assessed resection margins and tumor infiltration in resected specimens. Statistical analysis compared outcomes between patients with and without 3D planning. Results: The 3D models demonstrated 100% concordance with intraoperative vascular anatomy. Radiologically dense adipose tissue, resected as potentially tumor-infiltrated, showed histopathological invasion in 74% of cases. R0 resection was achieved in 74.4% of patients. Operative time decreased from 300 to 250 min after technical optimization, with a 7.7% conversion rate (primarily due to vascular injury or tumor fixation). Postoperative mortality was 5.1%, attributed to comorbidities. Patients with 3D planning had significantly higher lymph node yields (p < 0.00001) and R0 rates (p = 0.045). Conclusions: The integration of embryologically based topographic landmarks and 3D navigation improves the safety and standardization of laparoscopic gastrectomy for locally advanced gastric cancer. This approach enhances oncological radicality, reduces operative time, and mitigates risks in anatomically distorted fields. Further validation in larger cohorts is warranted. Full article

Three-dimensional bioprinting holds great promise for tissue engineering, but struggles with fabricating complex curved geometries such as vascular networks. Though precise, traditional Cartesian bioprinters are constrained by linear layer-by-layer deposition along fixed axes, resulting in limitations such as the stair-step effect. Multi-axis robotic bioprinting addresses these challenges by allowing dynamic nozzle orientation and motion along curvilinear paths, enabling conformal printing on anatomically relevant surfaces. Although robotic arms offer lower mechanical precision than CNC stages, accuracy can be enhanced through methods such as vision-based toolpath correction. This study presents a modular multi-axis robotic embedded bioprinting platform that integrates a six-degrees-of-freedom robotic arm, a pneumatic extrusion system, and a viscoplastic support bath. A streamlined workflow combines CAD modeling, CAM slicing, robotic simulation, and automated execution for efficient fabrication. Two case studies validate the system’s ability to print freeform surfaces and vascular-inspired tubular constructs with high fidelity. The results highlight the platform’s versatility and potential for complex tissue fabrication and future in situ bioprinting applications. Full article

Background/Objectives: Alterations in liver vascularization play a remarkable role in liver disease development, including hepatocellular carcinoma (HCC), but remain understudied. This study evaluated the hepatic microvascular imaging method and provided high-resolution quantitative anatomical data on the characteristics and architecture of liver vasculature in wild-type (WT) mice and HCC mouse models. Methods: C57BL/6 mice were injected with Akt/Ras or Sleeping Beauty transposon to induce HCC. Liver tissues from normal and Akt/Ras mice underwent hematoxylin and eosin, Masson’s trichrome, Ki67, and lymphatic endothelial receptor-1 staining. Using cutting-edge high-definition fluorescence micro-optical sectioning tomography, high-precision microvascular visualization of the liver was performed in WT and Akt/Ras HCC mice. Results: The sectioned volumes of normal and HCC liver tissues were 204.8 mm³ and 212.8 mm³, respectively. The microvascular systems associated with the tissues of the Akt/Ras HCC mouse were twisted, disordered, and compressed by tumor nodules. In the four tumor nodules, the path of the hepatic artery was more around the tumor edge, whereas the portal vein occupied the central position and constituted the main blood vessel entering the tumors. The porosity of HCC and paracancerous cirrhotic tissues was significantly less than that of normal tissues. The radii of the central vessels in the hepatic sinusoid of paratumoral cirrhotic tissues were significantly higher than those of normal tissues; however, the hepatic sinusoid density of paratumoral cirrhotic tissues was lower. Conclusions: This research provides a deeper understanding of the normal liver microvasculature and alterations in cases of cirrhosis and HCC, which complements scientific insights into liver morphology and physiology. This straightforward research approach involving the novel 3D liver microvasculature can be used in multiscale physiological and pathophysiological studies regarding liver diseases. Full article

The pancreas exhibits a uniquely intricate vascular architecture characterized by frequent and clinically significant morphological variations. These variations—impacting both arterial supply and venous drainage—are critical determinants in surgical planning, radiologic interpretation, and interventional outcomes. This comprehensive review examines the full spectrum of pancreatic vascular anatomy, with particular emphasis on embryological development, imaging manifestations, and surgical relevance. Key arterial structures, including the superior and inferior pancreaticoduodenal arteries (SPDAs and IPDAs) and the dorsal pancreatic artery (DPA)—are explored in detail alongside accessory branches. On the venous side, focus is placed on the gastrocolic trunk (GCT) of Henle, the uncinate and centro-inferior pancreatic veins, and the dorsal pancreatic vein (DPV). The review highlights that arterial aberrations, such as a DPA originating from the superior mesenteric artery (SMA), or duplicated patterns of the IPDA, as well as venous anomalies such as variant drainage of the GCT or the centro-inferior pancreatic vein, have substantial implications during pancreaticoduodenectomy, distal pancreatectomy, and transplantation procedures. With advances in multidetector computed tomography (MDCT), magnetic resonance angiography (MRA), and three-dimensional (3D) modeling, high-risk vascular variants can now be accurately mapped preoperatively, facilitating safer and more effective minimally invasive and robotic-assisted surgeries. In conclusion, the recognition and understanding of pancreatic vascular variations are imperative for optimal surgical and interventional management. This review underscores the importance of multidisciplinary collaboration among surgeons, radiologists, and anatomists, which will allow them to integrate detailed anatomical knowledge into clinical workflows, ultimately improving patient outcomes in pancreatic procedures. Full article

Background/Objectives: Orbital reconstruction remains one of the most demanding procedures in maxillofacial surgery. It requires not only precise anatomical knowledge but also poses multiple intraoperative challenges. Limited surgical visibility—especially in transconjunctival or transcaruncular approaches—demands exceptional precision from the surgeon. At the same time, the complex anatomical structure of the orbit, its rich vascularization and innervation, and the risk of severe postoperative complications—such as diplopia, sensory deficits, impaired ocular mobility, or in the most serious cases, post-traumatic blindness due to nerve injury or orbital compartment syndrome—necessitate the highest level of surgical accuracy. In this context, patient-specific implants (PSIs), commonly fabricated from zirconium oxide or ultra-high-density polyethylene, have become invaluable. Within CAD-based reconstructive planning, especially for orbital implants, critical factors include the implant’s anatomical fit, passive stabilization on intact bony structures, and non-interference with orbital soft tissues. Above all, precise replication of the orbital dimensions is essential for optimal clinical outcomes. This study compares the morphological accuracy of orbital structures based on anthropometric measurements from 3D models generated from fan-beam computed tomography (FBCT) and cone-beam computed tomography (CBCT). Methods: A cohort group of 500 Caucasian patients aged 8 to 88 years was analyzed. 3D models of the orbits were generated from FBCT and CBCT scans. Anthropometric measurements were taken to evaluate the morphological accuracy of the orbital structures. The assessed parameters included orbital depth, orbital width, the distance from the infraorbital rim to the infraorbital foramen, the distance between the piriform aperture and the infraorbital foramen, and the distance from the zygomatico-orbital foramen to the infraorbital rim. Results: Statistically significant differences were observed between virtual models derived from FBCT and those based on CBCT in several key parameters. Discrepancies were particularly evident in measurements of orbital depth, orbital width, the distance from the infraorbital rim to the infraorbital foramen, the distance between the piriform aperture and the infraorbital foramen, and the distance from the zygomatico-orbital foramen to the infraorbital rim. Conclusions: The statistically significant discrepancies in selected orbital dimensions—particularly in regions of so-called thin bone—demonstrate that FBCT remains the gold standard in the planning and design of CAD/CAM patient-specific orbital implants. Despite its advantages, including greater accessibility and lower radiation dose, CBCT shows limited reliability in the context of orbital and infraorbital reconstruction planning. Full article

Optical clearing agents (OCAs) offer a promising approach to enhance skin transparency by reducing scattering and improving photon transmission, which is critical for non-invasive optical diagnostics such as glucose sensing and vascular imaging. However, the complex multilayered structure of skin and anatomical variability across different regions pose challenges for accurately evaluating OCA performance. In this study, we developed a multilayer Monte Carlo (MC) simulation model integrated with a depth- and time-resolved diffusion model based on Fick’s law to quantitatively assess the combined effects of OCA penetration depth and refractive index change on optical clearing. The model incorporates realistic skin parameters, including variable stratum corneum thicknesses, and was validated through in vivo experiments using glycerol and glucose at different concentrations. Both the simulation and experimental results demonstrate that increased stratum corneum thickness significantly reduces blood absorption of light and lowers the clearing efficiency of OCAs. The primary influence of stratum corneum thickness lies in requiring a greater degree of refractive index matching rather than necessitating a deeper OCA penetration depth to achieve effective optical clearing. These findings underscore the importance of considering regional skin differences when selecting OCAs and designing treatment protocols. This work provides quantitative insights into the interaction between tissue structure and optical response, supporting improved application strategies in clinical diagnostics. Full article

This work explores the morphogenesis of the skeletal mineral component, with a specific emphasis on hydroxyapatite (HAp) crystal assembly. Bone is fundamentally a triphasic biomaterial, consisting of an inorganic mineral phase, an organic matrix, and an aqueous component. The inorganic phase (hydroxyapatite), is characterized by its hexagonal prismatic nanocrystalline structure. We leverage a cellular automata (CA) paradigm to computationally simulate the mineralization process, leading to the formation of the bone’s hydroxyapatite framework. This model exclusively considers the physicochemical aspects of bone formation, intentionally excluding the biological interactions that govern in vivo skeletal development. To optimize computational efficiency, a simplified anatomical segment of a long bone (e.g., the femur) is modeled. This geometric simplification encompasses an outer ellipsoidal cylindrical boundary (periosteal envelope), an inner ellipsoidal surface defining the interface between cortical and cancellous bone, and a central circular cylindrical lumen representing the medullary cavity, which accommodates the bone marrow and primary vasculature. The CA methodology is applied to generate the internal bone microarchitecture, while deliberately omitting the design of smaller, secondary vascular channels. Full article

Recent developments in 3D bioprinting offer innovative alternative solutions to classical treatments for head and neck defects. Soft tissues in an anatomical area as diverse in composition as the head and neck are complex in terms of structure and function. Understanding how cellular interaction underlies functionality has led to the development of bioinks capable of mimicking the natural morphology and roles of different human parts. Moreover, from the multitude of recently developed materials, there are now many options for building scaffolds that potentiate the activity of these cells. The fidelity and accuracy of the utilized techniques ensure maximum precision in terms of model construction. Emerging technologies will allow for improved control of the scaffold, facilitating optimal results in the treatment of various pathologies, without concerns about the availability of donors, immunological response, or any other side effects that traditional treatments withhold. This paper explores the current landscape of bioprinted scaffolds and their applications in the head and neck region, with a focus on the properties and use of natural and synthetic bioinks in the attempt to replicate the biomechanical features of native tissues. Customization capabilities that support anatomical precision and biofunctionality are also addressed. Moreover, regulatory requirements, as well as current challenges related to biocompatibility, immune response, and vascularization, are critically discussed in order to provide a comprehensive overview of the pathway to clinical application. Full article

Background and Clinical Significance: Robotic surgery reduces the need for extensive surgical approaches and lowers perioperative complications. In particular, it offers enhanced dexterity, three-dimensional visualization, and improved precision in confined anatomical spaces. Pelvic masses pose significant challenges due to their close relationship with critical neurovascular structures, making traditional open or laparoscopic approaches more invasive and potentially riskier. Robot-assisted resection, combined with intraoperative neurophysiological monitoring, may therefore offer a safe and effective solution for the management of complex pelvic lesions. Case Presentation: An 18-year-old woman was incidentally diagnosed with an 11 cm asymptomatic pelvic mass located anterior to the sacrum. Initial differential diagnoses included neurofibroma, teratoma, and myelolipoma. Histopathological examination confirmed a ganglioneuroma. Following multidisciplinary discussion, the patient underwent a robot-assisted en bloc resection using the Da Vinci Xi multiport system. Preoperative planning was aided by 3D modeling and intraoperative navigation. Conclusions: Surgery lasted 322 min. Preoperative and postoperative eGFR values were 145.2 mL/min and 144.0 mL/min, respectively. The lesion measured 11 cm × 9 cm × 8 cm. The main intraoperative complication was a controlled breach of the iliac vein due to its close adherence to the mass. No major postoperative complications occurred (Clavien-Dindo Grade I). The drain was removed on postoperative day 3, and the bladder catheter on day 2. The patient was discharged on postoperative day 5 without further complications. Presacral ganglioneuromas are rare neoplasms in a surgically complex area. A multidisciplinary approach using robotic-assisted laparoscopy with nerve monitoring enables safe, minimally invasive resection. This strategy may help avoid open surgery and reduce the risk of neurological and vascular injury. Full article

Background: Nasal reconstruction requires a balance between aesthetic and functional restoration. Recent advances in three-dimensional (3D) printing have introduced new approaches to this field, enabling precise, patient-specific interventions. This review explores the applications, benefits, and challenges of integrating 3D printing in nasal reconstruction. Methods: A literature search was conducted using PubMed, Scopus, and Web of Science to identify studies on 3D printing in nasal reconstruction. Peer-reviewed articles and clinical trials were analyzed to assess the impact of 3D-printed models, implants, and bioengineered scaffolds. Results: 3D printing facilitates the creation of anatomical models, surgical guides, and implants, enhancing surgical precision and patient outcomes. Techniques such as stereolithography (SLA) and selective laser sintering (SLS) enable high-resolution, biocompatible constructs using materials like polylactic acid, titanium, and hydroxyapatite. Computational fluid dynamics (CFD) tools improve surgical planning by optimizing nasal airflow. Studies show that 3D-printed guides reduce operative time and improve symmetry. Emerging bioprinting techniques integrating autologous cells offer promise for tissue regeneration. Challenges and Future Directions: Challenges include high costs, imaging limitations, regulatory hurdles, and limited vascularization in bioprinted constructs. Future research should focus on integrating bioactive materials, artificial intelligence-assisted design, and regulatory standardization. Conclusions: 3D printing offers specific advantages in nasal reconstruction, improving precision and outcomes in selected cases. Addressing current limitations through technological and regulatory advancements will further its clinical integration, potentially enhancing reconstructive surgery techniques. Full article