Medical Engineering & Physics最新文献

{"title":"Device-Specific Conformal Reliability under Scanner-Level Acquisition Shift in Breast Ultrasound CAD.","authors":"Ismail Hakki Kinalioglu","doi":"10.1088/1873-4030/aeb029","DOIUrl":"https://doi.org/10.1088/1873-4030/aeb029","url":null,"abstract":"<p><p>Conformal prediction provides finite-sample coverage control under exchangeability, but empirical reliability may change across scanner-defined deployment domains. We audit three conformal procedures and one non-conformal abstention baseline on leave-one-device-out (LODO) partitions of BUS-BRA using EfficientNet-B0, ResNet-50 and ConvNeXt-Tiny. All conformal thresholds are computed by direct finite-sample order-statistic indexing. The primary prediction and score unit is the image; source splits are patient-disjoint, target calibration/test partitions are patient-disjoint within each recalibration draw, and patient-cluster bootstrap plus patient-aggregated analyses assess within-patient dependence. At nominal α=0.05, EfficientNet-B0 Mondrian CP gives malignant set-miss rates of 0.004 for GE Logiq 7, 0.002 for GE Logiq 5 and 0.244 for Toshiba; the Toshiba patient-cluster 95% interval is 0.140-0.359. Patient aggregation preserves the contrast (0.194 for Toshiba versus 0.000 for both GE devices). In paired target recalibration, k=10 lowers Toshiba mean miss rate from 0.246 to 0.057 while increasing abstention to 0.603, whereas the same intervention raises the GE means to 0.060 and 0.067. Across the 500 Toshiba k=10 seed-draw combinations, the post-recalibration median miss rate is 0.021 (IQR 0.000-0.063), and 96.4% of draws improve relative to their paired pre-recalibration value. A finite-resolution analysis shows that α=0.02 is rank-unavailable for all tested few-shot conditions; under direct finite-sample order-statistic indexing, α=0.02 and α=0.05 coincide at k=5 and k=10 because both select the observed class maxima, but they separate in the larger k=20 condition. These results document scanner-level differences in empirical conformal reliability and motivate evaluating target recalibration when an independent target-domain reliability audit provides evidence of undercoverage, rather than establishing a prospective trigger rule.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149117467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of quantifying intra-fractional patient positional error for head and neck IMRT using radiomic features of EPID-measured fluence maps: a phantom study.","authors":"Takayuki Nishikata, Satoru Utsunomiya, Madoka Sakai, Tomotaka Kinoshita, Natsuki Ishizaka, Hisashi Nakano, Satoshi Tanabe, Ryuta Sasamoto, Yohan Kondo, Eisuke Wakatsuki, Hiroyuki Ishikawa, Takeshi Ito","doi":"10.1088/1873-4030/aea996","DOIUrl":"10.1088/1873-4030/aea996","url":null,"abstract":"<p><p>This study aimed to evaluate the feasibility of estimating patient positional errors during head-and-neck fixed-field intensity-modulated radiation therapy (IMRT) using a machine-learning (ML) regression models based on radiomics features of patient-transmitted fluence maps acquired by an electronic portal imaging device (EPID), as a proof-of-concept toward quantitative intrafractional monitoring. A virtual target, spinal cord, and parotid glands were contoured on an Radiosurgery Verification Phantom simulating nine fixed-field IMRT plans. Treatment plans were created with and without a 0.5 cm or 1.0 cm bolus placed on the phantom surface. For each field, phantom positional errors were simulated in the anterior-posterior (AP), left-right (LR), and superior-inferior (SI) directions at 1 mm intervals from -5 mm to 5 mm. Fluence maps were acquired using an EPID, and difference maps were generated between error and error-free cases. A total of 837 radiomics features were extracted. The dataset included 180 cases (with no bolus or 1.0 cm bolus) for training and 90 cases (with 0.5 cm bolus) for testing. Three ML regression models-random forest, AdaBoost and extra trees-were used. Positional error detection accuracy was evaluated using root mean square error (RMSE), mean absolute error (MAE) and Spearman's rank correlation coefficient. In the test data, RMSE values ranged from 0.550-0.779 mm (AP), 0.440-0.493 mm (LR), and 0.616-0.689 mm (SI). Corresponding MAE values ranged from 0.394-0.584 mm, 0.351-0.392 mm, and 0.492-0.573 mm, respectively. Spearman correlation coefficients ranged from 0.890-0.946 (AP), 0.949-0.953 (LR), and 0.860-0.898 (SI). This phantom-based study suggests that radiomics-based ML regression can quantitatively estimate translational positional-error magnitude from EPID-measured fluence differences under controlled conditions. These findings represent a proof-of-concept for the feasibility of intrafractional geometric monitoring rather than clinical validation. Further investigation using clinically realistic patient data, anatomical changes, and day-to-day machine variations is required before routine clinical implementation.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149002715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear Rate and Temperature Dependent Characterization of Blood-Mimicking Fluids for Blood Warming Device Application.","authors":"Andrea Riddle, Emine Foust","doi":"10.1088/1873-4030/aeae3d","DOIUrl":"https://doi.org/10.1088/1873-4030/aeae3d","url":null,"abstract":"<p><p>During emergency transfusion, stored whole blood at 1-6°C must be rapidly warmed to 36-38°C using blood warming devices. However, device validation commonly relies on Newtonian crystalloid intravenous fluids with a viscosity of 1 mPa·s, whereas whole blood exhibits temperature-dependent, shear-thinning rheology with viscosities of 3.5-4.5 mPa·s at 37°C. This discrepancy introduces systematic errors in performance evaluation. To address this gap, this research study characterized three blood-mimicking fluids (BMFs), including glycerol-water solutions of 22-50% w/w, egg whites, and TrueClot across temperatures of 5-40°C and shear rates of 5-100 s⁻¹. Among the tested fluids, TrueClot most closely resembled blood in overall rheological properties. However, TrueClot demonstrated abnormal phase separation at temperatures below 10°C, with a 28% drop in viscosity from 55 ± 4 to 39.6 ± 0.5 mPa·s over just 2°C, limiting its use at refrigerated storage temperatures. At shear rates ≥ 100 s⁻¹, 50% glycerol-water solutions produced viscosity values closest to reported whole blood values. Based on the rheological profiles obtained, it is inferred that at shear rates < 100 s⁻¹, diluted TrueClot at temperatures higher than 10°C or modified egg whites with xanthan gum at 5-40°C may provide suitable shear-thinning properties, though experimental validation of these modified solutions is required. Two mathematical models, including the Casson model with Apostolidis and Beris parametrization and a combined shear-temperature power law model, were developed to predict viscosity values that correlate well with the experimental results.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149117426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability-aware transfer learning with BEATs for variable-length respiratory sound classification: a patient-disjoint evaluation in two public databases.","authors":"Jie Niu, Peng Li","doi":"10.1088/1873-4030/aea851","DOIUrl":"10.1088/1873-4030/aea851","url":null,"abstract":"<p><p>Random or central placement of respiratory sounds within padded windows can cause length-based masks to exclude recorded audio. We developed an exact support-propagation interface for the pretrained bidirectional encoder representation from audio transformers (BEATs), mapping sample support through filterbank frames and patch tokens to attention and pooling masks. We evaluated this interface alongside adaptation strategies, computational costs, probability calibration and class-conditional coverage. The study included 15 987 events from the International Conference on Biomedical and Health Informatics (ICBHI) 2017 and SPRSound databases, using patient-disjoint training, model-selection, calibration and primary test partitions at a fixed decision threshold of 0.5. The three-seed full-fine-tuning ensemble achieved average scores (AS; mean sensitivity and specificity) of 0.6619 on ICBHI (patient-cluster bootstrap 95% confidence interval, 0.6002-0.7152) and 0.9112 on SPRSound (0.8799-0.9362). Exact mapping corrected observed support exclusion and maintained finite outputs throughout placement tests; the length-based interface produced non-finite outputs in these tests and one of three matched training runs. Classification ablations showed no consistent advantage for exact mapping across the two completed seed pairs and no incremental gain from Jensen-Shannon consistency. Under matched update counts and learning-rate schedules, full fine-tuning exceeded rank-8 low-rank adaptation (LoRA) by 3.94 percentage points in AS averaged equally across databases (paired patient-cluster bootstrap 95% confidence interval, 2.54-5.40). LoRA reduced trainable parameters and recorded training time but did not reduce inference latency in the unmerged implementation. Temperature scaling improved the primary ensemble's held-out negative log-likelihood and Brier scores without uniformly improving calibration error. Entropy-based abstention achieved low accepted-set error but failed the prespecified validation requirement for adventitious-event coverage and was not applied. The integrated evaluation quantifies performance-resource trade-offs and shows that improved probability scores do not ensure adequate class-specific coverage for selective prediction. Clinical utility requires prospective validation.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148984073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Honest and Reliable Evaluation and Expert Equivalence Testing of Automated Neonatal Seizure Detection.","authors":"Jovana Kljajic, John M O'Toole, Robert Hogan, Tamara Skoric","doi":"10.1088/1873-4030/aea852","DOIUrl":"10.1088/1873-4030/aea852","url":null,"abstract":"<p><p>Reliable evaluation of machine learning models for neonatal EEG seizure detection is a prerequisite for accurate performance assessment and comparison of methods. Model evaluation, however, is complicated by severe class imbalance and uncertain ground truth. To address these limitations, we propose evidence-based reporting recommendations tailored to the specific challenges of neonatal seizure detection. Using real and synthetic seizure annotations, we assessed standard performance metrics, consensus strategies, and human-expert level equivalence tests under varying class imbalance, inter-rater agreement, and number of raters. Matthews and Pearson's correlation coefficients outperformed the area under the receiver operating characteristic curve in reflecting performance under class imbalance. Consensus types are sensitive to the level of agreement and number of raters. Among the evaluated human-expert level equivalence tests, the multi-rater statistical Turing test using Fleiss'demonstrated the most consistent performance and robustness under the tested experimental conditions. Based on our findings, we recommend reporting: (1) at least one balanced metric, (2) sensitivity, specificity, PPV and NPV, (3) seizure burden agreement, (4) multi-rater agreement using the statistical Turing test with Fleiss', and (5) all of the above on a held-out validation set. This proposed framework provides an important prerequisite to clinical validation by enabling a thorough and honest appraisal of machine-learning or AI methods for neonatal seizure detection.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148983993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volume-constrained wall motion alters left atrial appendage hemodynamic descriptors: a CFD sensitivity study.","authors":"João Lameu Silva Junior, Júlio Gallinaro Maranho, Rodrigo de Lima Amaral","doi":"10.1088/1873-4030/aea6df","DOIUrl":"10.1088/1873-4030/aea6df","url":null,"abstract":"<p><p>Rigid-wall left atrium (LA) and left atrial appendage (LAA) computational fluid dynamics models are practical but suppress deformation-driven transport, whereas image-derived wall motion is data- and processing-intensive. We evaluated whether a reduced-order, volume-constrained wall-motion prescription changes computed LA/LAA hemodynamic descriptors relative to a static-wall approximation. A patient-specific LA/LAA geometry was combined with literature-informed phasic volumes and boundary conditions to simulate healthy dynamic, grade-II diastolic dysfunction (DD II) dynamic, and DD II static configurations. The healthy-DD II comparison represents a composite disease-state contrast; the DD II dynamic-static pair isolates wall-motion sensitivity within the same DD II setup. Numerical verification supported the intermediate mesh,s, five simulated cycles, and the laminar model for the monitored WSS waveform. Suppressing DD II wall motion reduced mean LAA time-averaged wall shear stress (TAWSS) from 0.05 to 0.01 Pa and increased the analyzed atrial surface fraction with TAWSSPa from 14.4% to 22.4%. Complete-wall, area-weighted medians changed consistently: TAWSS decreased from 0.570 to 0.349 Pa, whereas oscillatory shear index, relative residence time, and endothelial cell activation potential increased from 0.121 to 0.190, 2.52 to 5.02 Pa, and 0.217 to 0.539 Pa, respectively. Atm s, mean persistent volume stasis was similar in the two DD II cases, but the volume with low velocity during at least 90% of the cycle increased from 28.5% to 33.8%. Thus, suppressing prescribed deformation shifted the computed LA/LAA environment toward lower shear, greater shear-directional oscillation, and more spatially persistent low velocity. Volume-constrained motion is therefore useful as an engineering sensitivity tier when image-derived kinematics are unavailable; it is not a validated surrogate for regional atrial motion or a patient-specific predictor of thrombosis.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148972204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomechanical evaluation of a poly(vinyl alcohol) hydrogel testicular prosthesis for tissue-mimicking soft-tissue replacement.","authors":"Ruby Dhaliwal, Jaymes Schmidt, Ryan Flannigan, Hadi Mohammadi","doi":"10.1088/1873-4030/ae9bc3","DOIUrl":"10.1088/1873-4030/ae9bc3","url":null,"abstract":"<p><p>Current testicular prostheses are predominantly manufactured from silicone elastomers and often fail to reproduce the biomechanical and viscoelastic characteristics of native testicular tissue. This study aimed to develop and mechanically characterize a poly(vinyl alcohol) (PVA) hydrogel-based testicular prosthesis with tissue-mimicking properties. PVA hydrogels with concentrations of 5%, 10%, and 15% (w/v) were fabricated using a freeze-thaw crosslinking process and evaluated through comprehensive mechanical testing, including uniaxial compression, tensile testing, stress relaxation, creep, dynamic mechanical analysis, and cyclic compression fatigue testing. A prototype hydrogel testicular prosthesis was subsequently fabricated and its mechanical performance compared with native testicular tissue and a commercially available silicone implant. Mechanical behavior was strongly dependent on polymer concentration. Increasing PVA concentration resulted in significant increases in compressive modulus, tensile strength, toughness, storage modulus, and fatigue resistance. The 10% PVA hydrogel demonstrated the closest overall agreement with native tissue, exhibiting a compressive modulus of 78 ± 10 kPa compared with 64 ± 12 kPa for native tissue, while maintaining comparable tensile strength, recovery ratio, and energy dissipation characteristics. Viscoelastic characterization revealed tissue-like stress relaxation and creep responses, whereas cyclic compression testing demonstrated stable mechanical performance over 1000 loading cycles. In contrast, the silicone implant exhibited lower compliance, reduced energy dissipation capacity, and inferior overall biomechanical similarity to native tissue. These findings demonstrate that freeze-thaw PVA hydrogels provide a promising platform for biomimetic testicular prostheses. By tailoring polymer concentration, hydrogel implants can achieve mechanical and viscoelastic properties that more closely replicate native tissue than conventional silicone devices. The proposed hydrogel-based approach may improve implant realism and patient outcomes, providing a foundation for future long-term durability studies and<i>in vivo</i>evaluation.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148800827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Portable RGB-D stabilometry for unsupervised postural assessment in Antarctic field conditions.","authors":"Petr Volf, Marek Sokol, Lýdie Leová, Jan Hejda, Patrik Kutílek","doi":"10.1088/1873-4030/aea621","DOIUrl":"10.1088/1873-4030/aea621","url":null,"abstract":"<p><p>Portable quantification of postural sway remains challenging in remote and resource-limited environments where laboratory force platforms and motion-capture systems are impractical. We evaluated an autonomous RGB-D stabilometry workflow during an Antarctic expedition by comparing camera-derived center-of-mass (CoM) sway with a portable center-of-pressure (CoP) reference and testing leave-one-subject-out calibration. Thirteen participants performed modified Romberg trials while an Intel RealSense D455 camera and a Wii Balance Board (WBB) recorded postural data. Full-body CoM trajectories were reconstructed from three-dimensional landmarks; facial-landmark head tracking was evaluated as a secondary fallback modality. In total, 192 quality-controlled WBB-camera pairs were analyzed. Temporal-alignment diagnostics showed strong anteroposterior signal overlap with the CoP reference (median post-lag Pearson= 0.847-0.929 for full-body tracking;= 0.825-0.905 for head tracking). Raw full-body metrics underestimated root-mean-square anteroposterior sway (bias =5.62 mm) and overestimated mean velocity (bias = 8.67 mm s). Passing-Bablok calibration reduced RMS AP bias relative to the WBB reference to 0.01 mm and narrowed the width of the limits of agreement from 12.15 to 7.15 mm. After empirical mapping, the inter-method reliability of Rambling RMS AP sway relative to the WBB reference was excellent (ICC(2,1) = 0.956), whereas mediolateral outcomes were less reliable and should be interpreted as exploratory in this camera configuration, likely reflecting lower ML amplitude and three-quarter camera geometry. Clock-based fixed windows yielded lower correlations, whereas a single global acquisition-latency correction applied identically to all trials, without per-trial window optimization, recovered correlations close to those of the optimized analysis. All estimates are relative to the portable WBB field reference rather than a laboratory-grade standard, and the calibration is a task- and setup-specific empirical mapping, not a universal biomechanical transformation.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148945259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fig-based phantom materials for benchtop evaluation of endovascular devices in chronic post-thrombotic venous obstruction.","authors":"Zhaokun Zhang, Minhaj S Khaja, Ben Houle, Andrea T Obi, Albert J Shih","doi":"10.1088/1873-4030/ae9ff9","DOIUrl":"10.1088/1873-4030/ae9ff9","url":null,"abstract":"<p><p>This study investigates a fig-based phantom material for benchtop evaluation of endovascular devices intended for treatment of chronic post-thrombotic venous obstruction, a common sequela of deep vein thrombosis. The proposed phantom is designed to reproduce selected functional mechanical characteristics relevant to device interaction with fibrotic, organized post-thrombotic lesions, is fabricated using controlled aging durations and temperatures to tune its mechanical properties. Phantom formulations were evaluated by combining clinician haptic feedback (device-mediated resistance and force transmission) assessment with uniaxial compression testing. Haptic feedback evaluation was performed by experienced interventional clinicians using a 1-10 similarity scale to assess correspondence with clinical recanalization procedures. Compression testing demonstrated formulation-dependent differences in mechanical behavior, while clinician evaluations indicated comparable levels of perceived procedural realism across the tested formulations. Exploratory correlation analyses revealed positive associations between compressive resistance and clinician similarity scores, although these relationships did not reach statistical significance. The fig-based phantoms exhibited a reproducible nonlinear compression response with strain-dependent stiffening, resembling the mechanical behavior of organized post-thrombotic tissue. Together, these results support the feasibility of using fig-based materials as controlled and reproducible surrogate lesions for functional benchtop testing. Such a platform could complement higher-fidelity biological models by enabling accessible and standardized early-stage evaluation of endovascular devices for chronic venous recanalization.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148851581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility and accuracy of low-angle, non-orthogonal biplane fluoroscopic 2D-3D registration for dynamic analysis of the thumb carpometacarpal joint.","authors":"Ryoya Shiode, Satoshi Miyamura, Tasuku Miyake, Hiroki Kondo, Toru Iwahashi, Hiroyuki Tanaka, Yoshito Otake, Yoshinobu Sato, Tsuyoshi Murase, Seiji Okada, Kunihiro Oka","doi":"10.1088/1873-4030/aea4b6","DOIUrl":"10.1088/1873-4030/aea4b6","url":null,"abstract":"<p><p><i>Background.</i>Accurate three-dimensional dynamic assessment of the thumb carpometacarpal (CMC) joint is important for understanding the pathomechanics of CMC osteoarthritis and evaluating treatment outcomes. Intensity-based biplane 2D-3D registration is a promising approach for dynamic bone motion analysis; however, conventional orthogonal biplane configurations are often difficult to implement for small-joint imaging in clinical settings.<i>Methods.</i>We validated the accuracy of intensity-based biplane 2D-3D registration for thumb CMC joint kinematic analysis using a phantom model under a low-angle, non-orthogonal biplane fluoroscopic configuration (53°). Registration-derived bone poses were compared with radiostereometric analysis-derived ground truth across 252 biplane fluoroscopic image pairs during palmar and radial abduction tasks. Translational and rotational errors were calculated for the thumb proximal phalanx, first metacarpal, trapezium, and second metacarpal.<i>Results.</i>The method achieved submillimeter mean overall component-wise translational errors for all evaluated bones (range: 0.11-0.31 mm). Mean overall component-wise rotational errors were below 3° for all bones (range: 0.44-2.64°). Larger axis-specific rotational root mean square errors were observed for the trapezium and thumb proximal phalanx, reflecting bone- and axis-dependent error patterns.<i>Conclusion.</i>Intensity-based biplane 2D-3D registration can provide sufficient accuracy for dynamic analysis of the thumb CMC joint using a low-angle, non-orthogonal biplane configuration. This approach may serve as a clinically feasible platform for assessing small-joint kinematics in settings where conventional orthogonal biplane systems are difficult to implement, supporting future<i>in vivo</i>studies of dynamic thumb CMC joint motion.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148921720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}