Search Results (387)

Background/Objectives: Accurate visualization of peroneal perforator vessels prior to autologous transplantation of osteomyocutaneous fibular flap is essential for surgical success. Our aim was to improve and simplify pre-surgical diagnostics of peroneal perforators using a dedicated dual-energy Computed Tomography Angiography (CTA) protocol and semiautomatic Vessel Unfolding Reconstruction algorithm (VUR). Methods: CTA of both lower legs was performed in 22 patients using dual-energy acquisitions from a third-generation dual-source CT scanner and a high iodine flux (7 mL/s, 350 mg/mL). Low-energy virtual monoenergetic reconstructions (40 keV) were automatically reconstructed from the scanner and used for centerline labeling of the peroneal arteries and their perforators on a post-processing console using a dedicated vascular workflow. Separate segmentation and curved multiplanar reconstructions (MPRs) of each identified peroneal perforator vessel were regarded as the gold standard. Traditional visualization techniques of the entire volume like thin-slice maximum intensity projections (MIPs) or the volume rendering technique (VRT) were compared to a new VUR algorithm that aimed to adjust the visualization plane to the course of the vessels. The identified numbers and lengths of the perforator arteries were compared between curved MPRs, thin-slice MIPs in oblique coronal orientation, posterior-view VRT and coronal VUR of each lower leg. Results: The VUR algorithm was feasible in all patients and the same quantity of peroneal perforator vessels could be detected in comparison to the gold standard. The mean number of perforator vessels per lower leg was 2.6. Mean perforator length in VUR was slightly shorter by 1.6% and did not significantly differ from curved MPRs (p = 0.54), whereas length values from oblique coronal MIP and VRT reconstructions were significantly shorter (both p < 0.001). Conclusions: The combination of virtual monoenergetic reconstructions and the VUR algorithm enables comprehensive and precise depiction of small peroneal perforator vessels prior to autologous fibular flap transplantation, representing a diagnostic tool comparable to traditional visualization methods. Full article

Objectives: This study investigates the repeatability and reproducibility of radiomic features extracted from different energy levels of virtual monoenergetic reconstruction (VMER) and polyenergetic reconstruction (PER) obtained with photon-counting computed tomography (PCCT). Methods: Sixteen organic phantoms were scanned twice in a test–retest format using a 120 kV tube potential and tube currents of 10, 50, and 100 mAs. After rotating the phantoms 90° around their z-axis, additional test–retest scans were performed. A PER and 16 VMERs were generated. Segmentation and extraction of 105 original radiomic features followed. The repeatability and reproducibility of these features were assessed using the concordance correlation coefficient (CCC) for agreement and the intraclass correlation coefficient (ICC) for reliability, excluding 14 shape-based features from the analysis. Results: On average, 85 out of 91 radiomic features from VMER showed high repeatability. Approximately 30% of features demonstrated high intra-scan and inter-scan reproducibility when comparing PER and VMER. For different energy levels of VMER, around 78% showed high intra-scan reproducibility, and 74% showed high inter-scan reproducibility. Comparing the average values of test and retest scans in both the initial and rotated states revealed that 65% of features showed high agreement and 73% high reliability for PER, while for VMER, these values were 51% and 55%, respectively. Conclusions: Radiomic features from VMERs showed high test–retest repeatability, whereas reproducibility across reconstruction types and widely separated energy levels was more limited. These findings suggest that energy levels should be carefully standardized when radiomic features are extracted from PCCT-derived VMER images. Full article

Background: The sphenoid sinus occupies a strategically central position at the base of the skull, in close proximity to critical neurovascular structures including the pituitary gland, optic nerves, internal carotid arteries, and the cavernous sinus. Its complex anatomical configuration and pronounced individual variability render it a structure of paramount clinical importance in transsphenoidal approaches to the sellar and parasellar regions. Methods: A narrative review of the literature was conducted in accordance with the SANRA (Scale for the Assessment of Narrative Review Articles) guidelines for narrative reviews. A comprehensive search was performed across four electronic databases—PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar—covering publications from January 2000 through March 2026, with the final search update completed in March 2026. An initial pool of 826 articles was identified. Following title and abstract screening, 421 articles were retained for full-text assessment; of these, 307 contributed to the conceptual synthesis, and 100 are directly cited in the manuscript. The literature selection process followed a structured flow diagram consistent with PRISMA reporting principles for identification and screening stages. Results: We synthesise current evidence on the embryological development, macroscopic and microscopic anatomy, morphological classifications, and epidemiological distribution of anatomical variations in the sphenoid sinus, with emphasis on radiological assessment and surgical relevance. The spectrum of pneumatization patterns—from the conchal type through presellar and sellar variants to the postsellar, clival, and lateral types—is reviewed alongside population-level prevalence data. Common and rare variations are examined, including intrasinus septation, Onodi cells, and bony dehiscences overlying the internal carotid artery and optic nerve. The comparative diagnostic capabilities of computed tomography and magnetic resonance imaging are evaluated, alongside emerging modalities such as three-dimensional reconstruction, virtual reality, and augmented reality. Conclusions: Detailed morphological knowledge of the sphenoid sinus plays an important role in surgical strategy, instrument selection, and risk mitigation in skull base surgery. Individualised preoperative imaging—integrating CT, MRI, and, where available, immersive digital technologies—is essential for safe transsphenoidal planning and cannot be replaced by standard anatomical templates. Full article

Background/Objectives: Virtual Bronchoscopic Navigation is used to guide bronchoscopes toward peripheral pulmonary lesions, but broad clinical and research adoption remains limited by the cost of proprietary software and by segmentation failures in small distal airways that can interrupt path planning. This study presents Virtual Bronchoscopic Pathfinder, an open-source, web-based system designed to provide automated airway segmentation, robust path generation, and browser-based three-dimensional visualization. Methods: The system integrates five components: a connectivity-aware deep learning model for pulmonary airway segmentation using Connectivity-Aware Surrogate and Local-Sensitive Distance modules; TotalSegmentator for automated tumor localization; a topology-preserving three-dimensional thinning algorithm implemented in C++ for centerline extraction; a bidirectional Dijkstra algorithm operating on a three-tier anatomical cost field with centerline, airway lumen, and parenchymal costs; and a zero-footprint visualization interface built on vtk.js with synchronized axial viewing and interactive volume rendering. VBP was validated on 306 thin-section CT series from 154 subjects in the public Lung-PET-CT-Dx dataset. Results: Among the 306 CT series, 33 series (10.8%) were excluded because of scanner-specific segmentation artifacts. In the remaining 273 anatomically valid series, the system successfully generated complete end-to-end navigation paths for all cases. The overall pipeline success rate was therefore 273 of 306 series (89.2%). The web-based interface was also confirmed to operate without client-side installation across desktop, laptop, and mobile device configurations. Conclusions: Virtual Bronchoscopic Pathfinder demonstrates that a reliable and accessible virtual bronchoscopic navigation workflow can be constructed entirely from open-source components. By combining connectivity-aware segmentation, cost-field path planning, and browser-based visualization, the system provides a practical foundation for imaging informatics research and future development of intra-procedural bronchoscopic guidance. Full article

Background/Objectives: White–Sutton syndrome (WHSUS; OMIM 616364) is a rare neurodevelopmental disorder caused by pathogenic variants in the POGZ gene and characterized by developmental delay, intellectual disability, speech impairment, autism spectrum features, and dysmorphic traits. Although most reported cases are sporadic, inherited forms are exceptionally rare. We describe a familial case of WHSUS involving an affected mother and two children carrying a heterozygous POGZ nonsense variant, highlighting marked intra-familial phenotypic variability and expanding the clinical spectrum of the disorder. Methods: Clinical evaluation included multidisciplinary assessments. Genetic testing was performed using clinical exome sequencing (CES) with a virtual neurodevelopmental disorder (NDD) gene panel, followed by Sanger confirmation and segregation analysis in family members. The POGZ transcript reference NM_015100.3 was used for variant nomenclature and verified with the Mutalyzer tool. CNV detection from NGS data was performed using the Alissa CNV caller (Agilent) and visualized via IGV; the Xp11.22 microduplication was confirmed by chromosomal microarray (aCGH) and parental segregation analyses. Results: CES identified the heterozygous pathogenic POGZ variant c.1522C>T (p.Arg508*) in the female proband (III₆), an infant presenting with global developmental delay, hypotonia, speech impairment, gait abnormalities, and characteristic dysmorphic features. Segregation analysis demonstrated maternal inheritance and confirmed the presence of the variant in her affected brother (III₄), who also carries a de novo 1.79 kb microduplication at Xp11.22, while the maternal grandparents tested negative, indicating a de novo origin in the mother. The mother exhibited an attenuated phenotype, including mild neuropsychiatric and gastrointestinal manifestations. The variant is predicted to undergo nonsense-mediated decay (NMD), consistent with a moderate clinical presentation; however, experimental validation was not performed. Conclusions: This report documents a rare familial occurrence of WHSUS with highly variable expressivity. Our findings broaden the phenotypic and molecular characterization of POGZ-related disorders and emphasize the importance of comprehensive segregation studies and early genomic diagnosis. While experimental data link POGZ deficiency to DNA repair defects, no longitudinal clinical studies have demonstrated increased cancer risk in WHSUS; therefore, formal malignancy screening guidelines cannot be established at present, and this issue deserves future study in larger cohorts or registries. Full article

Coronary artery disease (CAD) remains a leading cause of global morbidity and mortality. Accurate diagnosis of ischemia-causing coronary stenoses is essential for guiding revascularization and improving outcomes. Although invasive fractional flow reserve (FFR) remains the gold standard for functional lesion assessment, its use is limited by procedural invasiveness, cost, and complexity. CT-derived FFR (FFRct), based on computational fluid dynamics (CFD), was the first major advance in noninvasive physiological assessment, but its adoption has been hindered by intensive off-site computation and dependence on high-quality imaging. This review summarizes the evolution from invasive FFR to AI-driven functional assessment of coronary lesions. We examine the principles and validation of CFD-based FFRct and then focus on the shift toward artificial intelligence, including both machine learning (ML) and deep learning (DL) approaches. These methods range from models using engineered geometric and plaque features trained on large synthetic datasets to end-to-end systems that learn directly from imaging data. We discuss key validation studies evaluating diagnostic accuracy, prognostic value, and clinical utility, with attention to performance in challenging settings such as intermediate stenoses, heavy calcification, and patients with comorbidities. We also highlight major barriers to widespread adoption, including dependence on input data quality, limited explainability, regulatory hurdles, and integration into clinical workflows. Finally, we outline future directions, including AI-enabled virtual PCI planning, multimodal risk stratification, and broader access to functional cardiac assessment. AI has the potential to transform noninvasive coronary imaging by enabling a single CCTA scan to provide rapid, integrated evaluation of anatomy, plaque characteristics, and physiological significance, supporting more personalized care and better clinical outcomes. Full article

As thoracic surgeons more frequently address smaller lung lesions and perform lung-sparing resections, their objective is to resect an adequate specimen and margin without removing excess healthy lung tissue. Although perioperative lung nodule localization has been in practice for decades, the existing and emerging techniques used for the identification of targeted and occult lesions are more widely utilized today than they were in the past. In this review, we detail the logic behind this increase in use, classify the techniques into preoperative and intraoperative categories, and define the specific modalities available. Where applicable, we review the published data comparing techniques, detailing efficacy and safety. In the preoperative space, we describe standard computed tomography (CT)-guided localization, virtual-assisted lung mapping, electromagnetic navigation bronchoscopy, robotic-assisted bronchoscopy, and novel fiducial markers. In the intraoperative space, we describe classical localization techniques, novel applications of intraoperative cone-beam CT, and fluorescence-guided surgery and intraoperative molecular imaging (IMI). Lastly, we review emerging approaches for intraoperative molecular imaging including a report on agents in early-stage clinical trials and a brief survey of promising preclinical models. With each approach mentioned, we analyze the potential benefits and hazards, and appraise the evidence for (or against) the use of any specific modality. Full article

Background/Objectives: Aztreonam/avibactam is a promising treatment option for serious infections caused by metallo-β-lactamase-producing carbapenem-resistant Enterobacterales (MBL-CRE). However, the labeled regimen is operationally demanding because it requires frequent, prolonged infusions, and the recommended loading dose does not match the commercially available vial strength. This population pharmacokinetic (PopPK)-based Monte Carlo simulation study aimed to optimize aztreonam/avibactam dosing across renal function strata while maintaining pharmacokinetic/pharmacodynamic (PK/PD) target attainment. Methods: Published PopPK models for aztreonam and avibactam were reconstructed and applied in Monte Carlo simulations. Virtual adult patients (body weight 70 kg) were stratified into five renal function groups according to creatinine clearance (CrCL): 101–120, 81–100, 51–80, 31–50, and 15–30 mL/min. Simulated scenarios varied infusion duration, dosing interval, maintenance dose, and loading strategy. Prespecified PK/PD targets were 60% fT > MIC (the percentage of dosing interval that free drug concentration remains above the minimum inhibitory concentration) for aztreonam (MIC 8 mg/L) and 50% fT > CT (the percentage of dosing interval that free drug concentration remains above the critical threshold concentration) for avibactam (CT 2.5 mg/L). A joint probability of target attainment (PTA) ≥ 90% was considered acceptable. Results: Regimen performance differed across renal function strata. For patients with CrCL > 80 mL/min, the labeled q6h regimen infused over 3 h remained the most robust option, whereas shortening the infusion to 1 h or 2 h reduced target attainment. In the CrCL 51–80 and 31–50 mL/min subgroups, both q6h/3 h and q6h/2 h regimens generally achieved acceptable PTA. However, in the CrCL 31–50 mL/min subgroup receiving q6h/2 h administration, omitting a loading dose was associated with reduced early avibactam exposure. In the CrCL 15–30 mL/min subgroup, a simplified half-vial regimen (0.75/0.25 g q8h/2 h) provided PTA comparable to that of the complex labeled reduced-dose regimen. Across loading dose scenarios, omission of the loading dose was best supported in the CrCL 51–80 mL/min subgroup, whereas retaining the labeled loading dose remained the more prudent approach in the CrCL 31–50 mL/min subgroup when a 2 h infusion was used. Conclusions: PopPK-guided, renal function-stratified simplification of aztreonam/avibactam dosing may improve clinical practicality without materially compromising PK/PD target attainment in selected patient subgroups. A 2 h infusion appears a reasonable alternative for patients with CrCL 31–80 mL/min, and a 0.75/0.25 g q8h/2 h half-vial regimen may be considered a plausible exploratory option for patients with CrCL 15–30 mL/min. These findings support more feasible administration strategies, but prospective clinical validation remains necessary. Full article

Efficient recovery of critical raw materials such as lithium from metallurgical slags requires optimized liberation of target phases during comminution. To determine effective mechanical process parameters for target phase recovery, an in-depth understanding of the characteristics of slag particles is crucial. For this purpose, modern tomography techniques, such as computed tomography (CT), can provide high-resolution 3D images of micrometer-sized slag particles. However, analysis of such CT images poses challenges, such as insufficient grayscale contrast between mineral phases and partial-volume effects. This paper presents a scalable workflow for accurate phase- and particle-wise 3D characterization of particle systems by correlating 3D CT images with 2D mineral maps. For this purpose, high-resolution scanning electron microscopy (SEM) slices are registered in 3D CT images and used as ground truth to train 3D convolutional neural networks (CNNs) for the segmentation of individual particles and mineral phases. This approach addresses the principal challenges of obtaining CT-based mineralogical characterizations, allowing for the particle-wise 3D characterization of complex slag systems with minimum manual labeling effort. The trained CNNs are then applied to CT images of particle systems with different particle sizes (from 63 μm to 100 μm and from 100 μm to 250 μm) of a lithium-bearing slag with LiAlO₂ as the target phase. Although virtual cross-sections of the predicted 3D segmentations show excellent agreement with mineral liberation obtained from 2D validation SEM-EDS data, the derived 3D mineral liberation statistics differ significantly from 2D estimates. In particular, our results show that the 2D analyses significantly overestimate mineral liberation compared to the 3D characterization. By addressing this stereological bias, the correlative 3D characterization workflow provides essential insights required to tailor pyrometallurgical and mechanical processing parameters to improve the recovery of raw materials. Full article

Thin-slice high-resolution computed tomography (CT) has improved the detection of small pulmonary nodules, increasing the demand for minimally invasive diagnostic and therapeutic resection. While lobectomy with lymph node dissection remains the standard surgical approach for many patients with resectable non-small cell lung cancer, accumulating evidence supports sublobar resection for selected small, peripheral, and ground-glass-dominant lesions when sufficient margins are achievable. In thoracoscopic and robotic surgery, localization of nodules ≤10 mm or lesions located >5 mm from the pleural surface can be challenging, and failure to identify the target may lead to conversion, larger resection than intended, or prolonged operative time. Several localization strategies have been developed, including CT-guided percutaneous wire/coil/dye marking, bronchoscopic dye mapping, and virtual-assisted lung mapping (VAL-MAP), robotic-assisted bronchoscopic dye or fiducial localization, radiofrequency identification microtag systems (Surgical Real-Time FInger Navigation and Detection) that provide real-time depth information, and single-stage intraoperative CT-guided marking and resection in hybrid operating rooms. This review synthesizes representative evidence and published outcome ranges, and compares workflows, marker-to-lesion precision metrics, complication profiles, operational burden, and cost structures. We emphasize the practical contrast between two-stage and single-stage workflows, the access-route differences between transthoracic and transbronchial techniques, and the need to report localization-to-incision “time at risk”. We also present an expert-consensus decision algorithm aimed at facilitating tailored selection of localization strategies for modern minimally invasive thoracic surgery. Full article

Background: Transcatheter mitral valve implantation (TMVI) represents an evolving therapeutic strategy for patients with severe mitral valve disease who are at high or prohibitive risk for conventional surgery. Since the first human implantation in 2012, multiple dedicated and adapted devices have entered clinical investigation, yet only one dedicated system—the Tendyne prosthesis (Abbott Structural)—holds regulatory approval. This systematic review evaluates the current landscape of available and emerging TMVI devices, examines the clinical outcome data, discusses key indications and limitations, analyses the role of computed tomography (CT) in predicting left ventricular outflow tract (LVOT) obstruction caused by the unopposed anterior mitral leaflet, and compares TMVI outcomes with conventional surgical mitral valve replacement (SMVR) in the specific context of severe mitral annular calcification (MAC). Methods: A systematic search of PubMed, EMBASE, Cochrane Central, and Web of Science was performed for studies published from January 2010 to March 2025 reporting outcomes of TMVI in native valve disease, valve-in-valve (ViV), valve-in-ring (ViR), or valve-in-MAC (ViMAC) procedures. Studies reporting CT-based LVOT planning, neo-LVOT quantification, and LVOT obstruction outcomes were specifically sought. Meta-analyses comparing TMVI with redo surgical mitral valve replacement were included. A total of 63 studies (n > 12,000 patients across all subgroups) were included in the qualitative synthesis; 28 studies were included in the quantitative synthesis. Results: Nine dedicated TMVI devices are currently under clinical investigation, with only Tendyne holding CE Mark and FDA approval. In ViV/ViR cohorts, TMVI was associated with significantly lower in-hospital mortality (OR 0.72, 95% CI 0.57–0.92; p = 0.008) and 30-day mortality (OR 0.49; p = 0.04) compared with redo SMVR, with no significant difference at one year (OR 1.03; p = 0.91). In ViMAC cohorts, 30-day mortality ranged from 14 to 24%, which was substantially higher than in the ViV outcomes. CT-based virtual simulation of the neo-LVOT area—the residual outflow tract created by anterior mitral leaflet displacement—is the most validated predictor of LVOT obstruction, with a threshold of ≤1.7 cm² yielding 96% sensitivity and 92% specificity. The LAMPOON technique (laceration of the anterior mitral leaflet to prevent outflow obstruction) has expanded the eligibility for patients who were previously excluded due to LVOT risk. Surgical MVR in severe MAC carries a median 30-day mortality of 6.3% (range 0–27.3%), while ViMAC TMVI with dedicated devices yields 6.8% 30-day mortality, without a definitive randomised comparison. Conclusions: TMVI offers a viable alternative to redo surgery in high-risk patients with failed bioprostheses or rings. In severe MAC, both surgical and transcatheter approaches carry significant risk; patient selection, CT-guided LVOT planning, and use of dedicated devices are critical to optimising outcomes. The ongoing SUMMIT randomised controlled trial will provide the first high-quality comparative data. Future developments in transseptal delivery and LVOT-safe device architectures are expected to broaden the eligible population. Full article

Radiotherapy simulation is essential for accurately targeting tumors while preserving healthy tissue, ensuring treatment precision and safety. This study aimed to develop an integrated radiotherapy simulation system capable of automated segmentation, dose estimation, and collision detection within a virtual planning environment to enhance efficiency and reduce costs in radiotherapy treatment planning. The Point Transformer model was applied to organ point cloud data derived from CT medical imaging for automated segmentation. Farthest point sampling (FPS) was employed to downsample the data before training. To enhance the accuracy and anatomical fidelity of the AI-generated segmentation results, reconstruction and refinement algorithms, including k-d tree, outlier removal, marching cubes, and surface smoothing, were implemented. Beam penetration simulation with the ray casting algorithm was employed for correction-based dose estimation. A collision detection module was incorporated to identify potential machine–machine or machine–patient interactions. The entire workflow was executed within a Unity 3D-based virtual simulation environment. As a result, the Point Transformer model demonstrated high segmentation accuracy, achieving Dice scores of 93.86 $\pm$ 1.50% for single-organ and 91.86 $\pm$ 3.25% for multi-organ cases, surpassing the performance of PointNet++. Applying ray casting for the refined surface meshes generated through post-processing enabled accurate dose estimation with discrepancies of 3.5% (brain), 5.9% (liver), and 13.8% (lung) compared to a Pinnacle TPS. The proposed method provides a low-cost and adaptable solution that enables easy modification and further development, making it particularly suitable for widespread applications in radiotherapy research, education, and clinical workflow optimization. Full article

Background: Differentiating adrenal adenomas from non-adenomatous lesions remains a critical challenge in the management of adrenal incidentalomas. Conventional unenhanced CT relies on attenuation thresholds of 10 HU and 20 HU, which present trade-offs between sensitivity and specificity. Objectives: To evaluate the diagnostic performance of unenhanced Spectral CT using the attenuation difference between 40 keV and 140 keV virtual monoenergetic images for differentiating adrenal adenomas from non-adenomatous lesions. Methods: In this retrospective single-center study, 60 patients with adrenal lesions who underwent unenhanced dual-energy CT were included. Mean attenuation values were measured on conventional images and on virtual monoenergetic images at 40 keV and 140 keV. The spectral attenuation difference (Δ40–140 keV) was calculated. ROC analysis was performed to determine the optimal threshold and diagnostic performance. Additional analyses included DeLong comparison of correlated ROC curves and bootstrap resampling to estimate 95% confidence intervals for the area under the curve. Results: Forty-nine lesions were adenomas and eleven were non-adenomatous. The optimal threshold for Δ40–140 keV was −17 HU. When evaluated as a continuous variable, Δ40–140 keV yielded an area under the curve of 0.940 (95% confidence interval: 0.851–1.000), compared with 0.939 (95% confidence interval: 0.870–0.992) for conventional unenhanced attenuation. DeLong comparison showed no statistically significant difference between the two curves (p = 0.980). Diagnostic performance was as follows: HU ≤ 10 (AUC 0.816, diagnostic accuracy 0.70), HU ≤ 20 (AUC 0.883, diagnostic accuracy 0.87), and Δ40–140 keV ≤ −17 HU (AUC 0.940, diagnostic accuracy 0.90). The spectral attenuation difference demonstrated the highest overall diagnostic accuracy. Conclusions: Unenhanced Spectral CT using Δ40–140 keV improves discrimination between adrenal adenomas and non-adenomatous lesions compared with conventional attenuation thresholds. This technique may reduce indeterminate findings and limit the need for additional imaging. Full article

Background and Objectives: Intramedullary headless screw (IMHS) fixation is a minimally invasive and biomechanically stable option for metacarpal fractures. However, the suitability of commonly used screw diameters may be limited by the morphometric features of the intramedullary canal. This study evaluated the isthmus morphology of the second to fifth metacarpals using computed tomography (CT)-based morphometric analysis and virtual screw simulation. Materials and Methods: A retrospective morphometric study was conducted using 75 hand CT scans, representing 300 metacarpals (second to fifth). Three-dimensional reconstructions were created with Mimics software (Materialise, Leuven, Belgium), and the isthmus level was identified by serial axial CT analysis. Canal diameters were measured at this level, and bone-specific virtual screw models were generated in Rhinoceros 3D and imported into Mimics for virtual implantation and canal conformity assessment. Feasibility rates were calculated for screw diameters between 2.75 mm and 4.00 mm. The effects of age and gender were also analyzed. Results: The fourth metacarpal had the smallest mean isthmus diameter (2.64 ± 0.89 mm), while the fifth had the largest (3.21 ± 0.84 mm). Feasibility decreased as screw diameter increased across all metacarpals. The fourth metacarpal showed the lowest compatibility, with feasibility rates of 10.7% for 3.5 mm screws and 4.0% for 4.0 mm screws. In contrast, the fifth metacarpal had the highest feasibility at smaller diameters, with 74.7% compatibility for 2.75 mm screws and 62.7% for 3.0 mm screws. Positive correlations were found between age and isthmus diameters of the second and third metacarpals, indicating age-related canal widening. Conclusions: The anatomical feasibility of IMHS fixation in the second to fifth metacarpals is influenced by isthmus morphology. The fourth metacarpal appears to be the most restrictive, particularly for screws ≥ 3.5 mm. These findings support individualized CT-based preoperative templating rather than standardized implant selection to improve screw canal compatibility and reduce cortical compromise risk. Full article

Background: Maxillary sinus lift is among the most common preprosthetic procedures in the posterior maxilla due to alveolar ridge resorption and the maxillary sinus pneumatization. It often extends treatment duration, significantly increases costs, and is not without complications. Objective: To explore the prevalence and morphology of the palatal bone reservoir as a viable site for dental implant insertion, offering a conservative alternative to avoid maxillary sinus lift. Methods: DICOM data sets from helical CT of maxillofacial trauma patients aged 50 years and older were used to perform virtual dental implant positioning in the edentulous second premolar, first molar, or second molar areas using ImplaStation software (version 5.3.2; ProDigiDent, Inc., Scottsdale, AZ, USA). A 3D Slicer software (version 5.3.2; ProDigiDent, Inc., Scottsdale, AZ, USA) was used to calculate the volume of the palatal bone reservoir and identify its mean density. The density of the residual alveolar process was also identified and compared with that of the previous one. Results: A total of 1822 maxillofacial trauma cases with helical CT between 2015 and 2025 were retrieved. After exclusion, 305 cases were analyzed. A total of 65 implants were virtually positioned in 50 patients. The mean volume of the palatal bone reservoir was 229 ± 139.2 mm³ with a mean radiodensity of 546.7 ± 159.6 HU. The mean radiodensity of the residual alveolar process was 286.3 ± 118.0 HU. The palatal bone reservoir was significantly denser than the residual alveolar process (95% CI [184.2, 336.6]; p < 0.01). Conclusions: The presence of a palatal bone reservoir is not uncommon and can offer a more conservative alternative for implant placement, potentially increasing primary stability and facilitating immediate loading. Full article