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Biomedical Optics Express

● Optica Publishing Group

Preprints posted in the last 7 days, ranked by how well they match Biomedical Optics Express's content profile, based on 95 papers previously published here. The average preprint has a 0.07% match score for this journal, so anything above that is already an above-average fit.

1
Cardiac MRI at 3.0T in the presence of implantable cardioverter defibrillators (ICDs)

Reiter, T.; Weber, O. M.; Weiss, i.; Kraus, N.; Kress, S.; Bauer, W. R.

2026-10-21 cardiovascular medicine 10.64898/2026.10.16.26364740 medRxiv
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Patients with implantable cardioverter-defibrillators (ICDs) often are excluded from receiving CMR scans at 3.0T due to ICD-induced image artifacts. This work aims to transfer sequence protocols established for CMR imaging in the presence of ICDs at 1.5T to a first human application at 3.0T. All measurements were performed on a clinical 3T MRI scanner. Phantom measurements were used to establish and optimize wideband PSIR LGE imaging at 3.0T. Volunteer measurements with externally placed ICDs were used for optimization of CINE imaging and wideband PSIR imaging. Thirdly, patients with implanted ICD were examined with the optimized protocols. Human measurements showed that SA stacks obtained with spoiled GRE after contrast agent showed a markedly lower artifact burden than the conventional approach. For scar imaging, a wideband PSIR with a bandwidth of 3kHz and a frequency offset of +750Hz allowed a sufficient suppression of relevant artifacts in the majority of scans. No strong correlation between the image quality and the distance between the cardiac silhouette and the device was detected. The presented work shows the feasibility of clinical cardiac MRI at 3.0T including GRE-CINE and wideband PSIR-LGE for patients with ICDs.

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Scaled m-BonacciNet: A Recurrence-Guided Lightweight CNN for Efficient Medical Image Classification

Habib, G.; Thakur, S.; Shaban, M.; Ahmad, R.; Malik, I. A.

2026-10-19 radiology and imaging 10.64898/2026.10.18.26362018 medRxiv
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The -Bonacci weighted sequence space {ell}(,) is introduced for [&ge;] 2, 1 [&le;] < {infty}, and > 0). It is proved to be a Banach space which is isometrically isomorphic to {ell}, with an unconditional Schauder basis. The space is also reflexive and uniformly convex. Its strict inclusion chain, continuous dual, and asymptotic truncation estimate of order - / are also established. Based on this framework, Scaled &#119898-BonacciNet is proposed as a lightweight CNN that rescales Fibonacci-Net channels using the dominant &#119898-Bonacci root and employs depth wise separable convolutions. Tribonacci-Net achieved 96.09% accuracy and a 0.9581 macro F1-score on the 15-class Brain MRI dataset using 0.85 million parameters and 0.366 GFLOPs. Pentanacci-Net attained 95.87% accuracy on the 44-class dataset while reducing parameters and FLOPs by 47.10% and 44.48%, respectively. On the CKD ultrasound dataset, Hexanacci-Net achieved 83.75% accuracy and a 0.7941 macro F1-score, with corresponding reductions of 50.37% and 45.10%. These findings support dominant-root scaling as a structured approach to lightweight CNN design.

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LUCID: Lipid-featured Urine Cytology with Intelligent Detection for Non-Invasive Early Diagnosis of Bladder Cancer

Hao, Z.; Liu, J.; Fang, T.; Zheng, Y.; Hu, H.; Hu, S.; Zhang, X.; Zhou, L.; Chen, X.; Yao, L.; Yue, S.

2026-10-16 urology 10.64898/2026.10.14.26365504 medRxiv
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Leveraging its non-invasive and convenient nature, urinary cytology offers a way for the early diagnosis and surveillance of bladder cancer (BCa). However, its sensitivity remains substantially inferior to the histopathological gold standard, rendering it inadequate to support precise clinical diagnosis. Here, we developed Lipid-featured Urine Cytology with Intelligent Detection (LUCID), an automated platform integrating single-cell stimulated Raman scattering (SRS) imaging and explainable AI model for accurate BCa detection. Following a newly developed standardized urine-preprocessing protocol, 19,678 urinary exfoliated cells from 26 BCa patients and 54 non-BCa participants were imaged using two-color SRS microscopy to simultaneously visualize lipid and protein distributions. For cell-level analysis, a customized deep-supervised Cellpose segmentation algorithm and a YOLO-based detection model were developed to enable precise single-cell segmentation and intracellular lipid droplet (LD) identification, respectively. Totally 20 quantitative morphological and compositional features per cell were extracted and 10 related principal components were obtained via principal component analysis. These features were subsequently integrated into a multiple-instance learning (MIL)-XGBoosting model, which achieved robust diagnostic performance, with 92.31% sensitivity, 87.04% specificity, and an AUC of 0.940. We found that morphological and compositional features provided complementary diagnostic information, while LD-associated features provided primary discriminative information, supporting intracellular LD phenotypes as potential urinary cellular markers of BCa. More importantly, LUCID demonstrated exceptional accuracy in detecting early-stage and small tumors, and showed higher concordance than FISH in a preliminary paired subset (5/6 vs. 2/6). Together, LUCID establishes a chemical imaging-AI paradigm that transforms molecular urine cytology.

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Left Ventricular Diastolic Intraventricular Pressure Differences and Propagation Velocity with 4D-Flow MRI in Patients with Hypertrophic Cardiomyopathy

Stipechi, L. V.; Craiem, D.; Gencer, U.; Casciaro, M. E.; Hulot, J.-S.; Hagege, A.; Soulat, G.; Mousseaux, E.

2026-10-21 cardiovascular medicine 10.64898/2026.10.15.26365692 medRxiv
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Background: Transthoracic echocardiography (TTE) remains the gold standard for assessing left ventricular (LV) diastolic dysfunction (DD), but noninvasive alternatives are needed to overcome geometric and acoustic limitations. 4D-Flow MRI enables comprehensive assessment of intraventricular pressure differences (IVPDs) and flow propagation velocity (VP). We aimed to evaluate 4D-Flow-derived IVPDs and VP in patients with hypertrophic cardiomyopathy (HCM). Methods: Thirty-eight HCM patients and 38 age- and sex-matched healthy controls underwent TTE and 4D-Flow MRI. Spatiotemporal maps of velocity and IVPDs, decomposed into inertial and convective components, were derived along the main inflow streamline from the mitral valve to the apex. Peak early filling rate (PEFR) was used to normalize IVPDs and VP. Results: While absolute peak flow rates were comparable, HCM patients exhibited significantly faster VP (100.4 vs. 60.2 cm/s, p < 0.01) and higher positive early E IVPD (1.40 vs. 0.92 mmHg, p < 0.01) compared to controls. Normalizing IVPDs by PEFR amplified group differences, revealing a markedly increased flow-normalized E-IVPD (5.13 vs. 2.94 x 103 mmHg.ml1.s, p < 0.001) and deeper reverse ER IVPD (-6.06 vs. -4.61 x 103 mmHg.ml1.s, p < 0.01) in HCM. These differences were primarily driven by the inertial components. Multivariable analysis demonstrated that ER IVPD is independently determined by PEFR and the TTE E/E' ratio (r = 0.65, p < 0.001). Conclusions: 4D-Flow MRI-derived, flow-normalized IVPDs and propagation velocity provide robust, noninvasive markers of altered LV chamber stiffness and impaired diastolic filling in HCM, offering deeper 3D hemodynamic insights into diastolic dysfunction.

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Evaluating the Interplay and Impact of Quality and Technical Variations on Performance of AI Models in Multi-Institutional Prostate MRI Datasets

Azamat, S.; Singh, A.; Midya, A.; Zhang, Z.; Gilkey, M.; Hajibonabi, F.; Sompalle, P.; Rastinehad, A.; Verma, S.; Kikano, E. G.; Sanda, M.; Hajiha, M. N.; Shiradkar, R.; Viswanath, S. E.; Madabhushi, A.

2026-10-19 radiology and imaging 10.64898/2026.01.19.26344376 medRxiv
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Purpose: To evaluate whether visually assessed high-quality prostate MRI, as defined by the Prostate Imaging Quality (PI-QUAL) scoring system, is sufficient to ensure consistent AI model performance, or whether hidden acquisition-related technical effects introduce variability that cannot be detected through visual inspection. Methods: This retrospective study included 568 bpMRI scans from seven institutions, classified using PI-QUAL v2 into high-quality (scores 2-3) and low-quality (score 1) groups. Quantitative image quality features were extracted using MRQy from T2w and ADC sequences. Three experiments were conducted on high-quality scans: (1) unsupervised clustering to identify hidden technical batch effects; (2) V-Net models (M) for prostate capsule segmentation on T2w using single-cluster and balanced multi-cluster training strategies; and (3) VoxelMorph-based deformable registration (M2) to align ADC maps to T2w images. Performance metrics included DSC, precision, recall, volume ratio, HD95, ASSD, and TRE. Kruskal-Wallis tests assessed cross-cluster variability, Two One-Sided Tests (TOST) evaluated performance equivalence, and bootstrap resampling quantified training efficiency. Results: Clustering identified four clusters among 277 high-quality bpMRI scans. Single-cluster models showed variable performance (DSC=0.41-0.85) with significant batch effects (p<0.001), even with 140 training samples. The balanced multi-cluster model (n=60) eliminated batch effects (p=0.075), achieved equivalent performance (p<0.001), and demonstrated 2.23-fold greater training efficiency despite using 2.3-fold fewer samples. Registration performance also varied significantly across clusters (TRE=0.86-5.47 mm, p<0.001). Conclusion: Acquisition-related batch effects significantly impact AI generalizability in prostate MRI, even among high-quality scans. Quantitative clustering enables detection of technical variations and supports diversity-aware training strategies that achieve equivalent performance with 2.3-fold fewer samples while eliminating batch effects.

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Fully Automated Multi-Chamber Strain Profiling in Consecutive Patients Undergoing Transthoracic Echocardiography: Feasibility, Functional Clustering, and Prognostic Implications

Noh, S. A.; Park, J.; Yoon, Y. E.; Jeon, J.; Jang, Y.; Lee, S.-A.; Bak, M.; Choi, H.-M.; Hwang, I.-C.; Cho, G.-Y.

2026-10-21 cardiovascular medicine 10.64898/2026.10.20.26365880 medRxiv
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Aims: Myocardial strain enables sensitive assessment of cardiac function, but its clinical application has largely focused on individual chambers or selected patient populations. We evaluated the feasibility and clinical relevance of fully automated multi-chamber strain assessment in consecutive patients undergoing routine transthoracic echocardiography (TTE). Methods and results: This retrospective study included 8,350 consecutive adults undergoing TTE. A hospital-wide artificial intelligence (AI)-based system automatically measured left ventricular (LV) global longitudinal strain (LVGLS), left atrial (LA) reservoir strain (LASr), and right ventricular (RV) free-wall strain (RVFWS). AI-derived LVGLS was available from at least one apical view in 97.1% of patients and from all three views in 94.8%; LASr and RVFWS were available in 94.1% and 94.5%, respectively, resulting in complete multi-chamber strain assessment in 90.3%. Strain measures showed modest correlations with conventional chamber-specific echocardiographic parameters and differential associations with clinical outcomes. Gaussian mixture modeling identified three distinct clusters characterized by preserved multi-chamber function, RV-dominant dysfunction, and pan-chamber dysfunction. Compared with the preserved cluster, pan-chamber dysfunction was associated with the highest risk of all-cause death or heart failure hospitalization (adjusted hazard ratio, 3.44; 95% CI, 2.43-4.88; P<0.001). Prognostic associations remained evident in patients with LV ejection fraction (LVEF) [&ge;]50%, and cluster assignment provided incremental prognostic information beyond clinical factors, LVEF, and RV fractional area change. Conclusions: Fully automated multi-chamber strain assessment was feasible in a large consecutive TTE cohort. Integrating strain across cardiac chambers may provide complementary functional characterization and identify clinically relevant clusters with prognostic information beyond conventional assessment.

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Heart rate variability and electrocardiographic parameters among workers exposed to chronic intermittent hypobaric hypoxia in the Peruvian Andes: A cross-sectional study Cardiac autonomic function in Andean workers

Montes-Madariaga, E. S.; Ortiz-Saavedra, J. B.; Mamani Castillo, J. S.; Valencia-Pacheco, A. I.; Ballon Echegaray, J. A.; Paz Torres, I. L.; Leon Vasquez, R. A. J.

2026-10-16 cardiovascular medicine 10.64898/2026.10.15.26365599 medRxiv
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Chronic intermittent hypobaric hypoxia is an occupational exposure experienced by workers who alternate between high-altitude worksites and lower-altitude resting locations. Its effects on cardiac autonomic modulation and electrocardiographic parameters remain insufficiently characterized in Andean workers. This study aimed to compare heart rate variability and electrocardiographic parameters between workers exposed to chronic intermittent hypobaric hypoxia and controls working permanently at lower altitude in Arequipa, Peru. An observational cross-sectional study was conducted in 96 male workers aged 20-60 years. The exposed group included 53 workers performing rotational shifts at altitudes [&ge;]3,000 m above sea level with rest periods at <2,500 m, while the control group included 43 workers working permanently at <2,500 m. Heart rate variability was assessed during the morning rest period in Arequipa, at approximately 2,300 25 m above sea level, using a Polar(R) H10 heart rate sensor after 15 minutes of rest. Participants also underwent standard 12-lead electrocardiography. Vital signs were clinically similar between groups. No statistically significant differences were observed in PR interval, corrected QT interval, time-domain heart rate variability parameters, or frequency-domain heart rate variability parameters. In this sample of apparently healthy male workers evaluated during their rest period at moderate altitude, exposure to chronic intermittent hypobaric hypoxia was not associated with significant differences in resting heart rate variability or standard electrocardiographic parameters.

8
Interictal functional ultrasound imaging in human epilepsy resection and responsive neurostimulation surgery

Agyeman, K. A.; Lee, D.; Lee, B. P.; McGinn, R. J.; Abedi, A.; Russin, J.; Wu, K.; Choi, w.; Liu, C.; Christopoulos, V. N.

2026-10-20 neurology 10.64898/2026.10.15.26365563 medRxiv
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Over 30% of patients with epilepsy are refractory to medication and may require surgical or neuromodulation-based intervention. Accurate localization of seizure-onset zones (SOZ) and assessment of treatment-associated brain responses remain major clinical challenges. Current workflows may involve invasive intracranial monitoring, prolonged hospitalization, adjustment of anti-seizure medications, and seizure capture to localize the SOZ, while opportunities for complementary intraoperative functional assessment remain limited. We used intraoperative functional ultrasound imaging (fUSI) to characterize interictal (i.e., non-seizure) cortical activity in nine patients with drug-resistant focal epilepsy and to assess treatment-associated brain responses following SOZ resection and responsive neurostimulation (RNS). fUSI signals were acquired directly from the exposed cortex during standard-of-care surgery. We developed six ultrafast power Doppler-based interictal activity markers (IaMs) to distinguish SOZ from peri-resection zone (PRZ) cortex and to quantify treatment-associated changes. The IaMs revealed distinct interictal hemodynamic dynamics between SOZ and PRZ cortex. Following SOZ resection, all six markers changed significantly within the surrounding PRZ. RNS also induced robust, stimulation paradigm-dependent modulation of cortical hemodynamic dynamics. Notably, RNS and surgical resection produced concordant directional changes across five of the six IaMs, despite representing fundamentally different therapeutic interventions. Together, these findings demonstrate the feasibility of intraoperative fUSI for characterizing and distinguishing interictal dynamics within SOZ and PRZ cortex and assessing treatment-associated cortical responses during human epilepsy surgery. Furthermore, fUSI could provide a complementary high-resolution functional imaging approach alongside established clinical methods for SOZ localization and intraoperative functional assessment.

9
Discrepancies in Interpretation of Japanese Radiology Report Expressions Between Radiologists and Referring Physicians

Yamaguchi, T.; Matsuo, H.; Nishio, M.; Inukai, J. I.; Matsunaga, T.; Kojita, Y.; Sofue, K.; Murakami, T.

2026-10-21 radiology and imaging 10.64898/2026.10.19.26364709 medRxiv
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Objectives To evaluate discrepancies between radiologists and referring physicians in the interpretation of diagnostic probabilities conveyed by common Japanese expressions used in radiology reports. Materials and Methods Fifteen expressions commonly used to convey diagnostic probabilities in radiology reports were selected by five attending radiologists. An anonymous online survey was distributed to 26 radiologists and 33 referring physicians at a single institution. Participants assigned a diagnostic probability (from 0% to 100% in 10% increments) to each expression. Differences in median probabilities between radiologists and referring physicians were analyzed using the Mann-Whitney U test. Variability in interpretation was assessed using interquartile range (IQR), with IQR [&ge;] 30% defined as substantial variability. Results All radiologists (26/26) and 97% of referring physicians (32/33) completed the survey. Seven of the 15 expressions showed statistically significant differences in interpretation between radiologists and referring physicians: "c/w" (80% vs. 60%; p = 0.031), the Japanese equivalents of "present" (100% vs. 100%; p = 0.024), "suspect of" (80% vs. 70%; p = 0.007), "possibly" (50% vs. 70%; p < 0.001), "unlikely" (10% vs. 10%; p = 0.022), "cannot be ruled out" (25% vs. 40%; p < 0.001), and "not inconsistent with" (80% vs. 90%; p = 0.008). Substantial variability in interpretation (IQR [&ge;] 30%) was observed for four expressions: "cannot be ruled out" (IQR, 10%-40%), "s/o" (IQR, 60%-90%), "c/w" (IQR, 50%-90%), and "not inconsistent with" (IQR, 70%-100%). Conclusion This study revealed that nearly half of the Japanese expressions commonly used to convey diagnostic probabilities were interpreted differently by radiologists and referring physicians. These discrepancies highlight the need for a standardized lexicon to improve clarity and consistency in radiology reporting.

10
AI-Assisted Interpretation of Neurologic Autoantibody Cell-Based Assays

Qi, Z.; Cao, Z.; Tan, H.; Tang, B.; Shi, S. X.; Jia, R.; Yao, Y.; Chen, J.; Zhang, Z.; Wan, J.; Zheng, P.

2026-10-19 neurology 10.64898/2026.10.16.26365578 medRxiv
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Neurologic autoantibody cell-based assay images are difficult to interpret when fluorescence is weak, focal or dominated by background signal. We developed a visual artificial intelligence overlay that transfers detected cell boundaries from the structural channel to the antibody-staining image and evaluated standalone model concordance and its association with reader classifications. The analysis used 2 763 records for model development and 499 held-out records spanning 14 antibody targets. Four readers assessed the held-out records first without assistance and then with the boundary overlay and model category available. The selected model agreed with the reader-derived three-class reference in 85.2% of records, but recall was lowest for weak-positive or equivocal records. Reader agreement increased in the assisted session, and almost all revised ratings moved towards the model category. The combined display may support consistent visual review while also creating a risk of model-directed anchoring; its role as a second-read aid requires independent validation.

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Deep Learning-Based Anatomical Level Classification of Craniofacial CT Slices: Comparison of CNN Architectures and Ensemble Methods

Nishimoto, S.; Nakajima, K.; Yoshiike, H.; Ishise, H.; Saito, T.; Kawai, K.

2026-10-19 radiology and imaging 10.64898/2026.10.16.26365710 medRxiv
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Computed tomography (CT) interpretation requires recognition of the anatomical level of each slice. Classification may facilitate preprocessing and AI-assisted fracture diagnosis. We developed deep learning models to classify craniofacial CT slices into six anatomical categories. A total of 11,769 images were collected from a multicenter database involving 10 Japanese university hospitals and the public Head-Neck-Radiomics-HN1 dataset. Patients were divided into training (70%) and evaluation (30%) sets. Five CNN architectures were trained from scratch, and hard- and soft-voting ensembles were evaluated. Individual-model accuracy ranged from 94.72% to 96.09%; the hard-voting ensemble achieved 96.46% accuracy (Cohen's k = 0.954). Although performance differed among individual models (Cochran's Q = 99.29, p < 0.001), the ensemble did not significantly outperform EfficientNetV2B1 (McNemar's p = 0.163). Errors occurred mainly between adjacent anatomical regions. Deep learning can classify craniofacial CT slices accurately and may support automated dataset organization and AI-assisted fracture diagnosis. External validation is needed.

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Clinical referral text overrides MRI evidence in multimodal large language models: glioma versus brain abscess

Beste, N. C.; Bauer, F.; Lopez, N.; Schoemig, T.; Schoenfeld, M.; Zopfs, D.; Goertz, L.; Persigehl, T.; Kabbasch, C.; Schlamann, M.; Maintz, D.; Gertz, R. J.; Weitzer, N.; Kottlors, J.

2026-10-19 radiology and imaging 10.64898/2026.10.17.26365809 medRxiv
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Objectives: To determine how strongly clinical referral text, rather than image content, drives the decisions of multimodal large language models (LLMs) differentiating glioma from brain abscess on MRI. Materials and methods: This retrospective single-center study included 60 contrast-enhanced T1-weighted brain MRI examinations (30 gliomas, 30 abscesses; reference-standard diagnosis). One axial slice per case was paired with five referral texts (explicitly inflammatory to explicitly tumor-suggestive) under three prompt instructions and submitted 20 times each to GPT-4o, Claude Sonnet 5, Gemini 3.5 Flash, and Qwen 3.6 (72,000 answers). The primary outcome was the text-driven span (difference in tumor-call frequency between explicit inflammatory and explicit tumor text). Two blinded radiologists classified the images without text; sensitivity, specificity, and accuracy were compared descriptively. Results: Patients (29 women) had a mean age of 55.8 +/- 16.4 years. With neutral text, models answered tumor in 45-67% of queries (specificity, 0.38-0.78), versus 52% and 60% for radiologists (specificity, 0.77 and 0.63). The text-driven span was 0.79-1.00 (p < 0.001 for all models), whereas confirmed gliomas and abscesses differed by only 0.01-0.10 in three models and 0.25 in Gemini 3.5 Flash. Subtle wording produced at least 83% of the span in three models. An instruction to ignore the text reduced the span to 0.48-0.70 in three models and to 0.04 in Gemini 3.5 Flash, partly through reversion to a tumor default. Model accuracy was 0.52-0.73 versus 0.78 and 0.73 for radiologists. Conclusion: Multimodal LLMs deferred to referral text over imaging evidence in differentiating glioma from brain abscess, and prompt instructions did not reliably correct this.

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Disagreement between AI and Radiologists: Quantifying Direction and Fragility

El Kaddouri, B.; Gevenois, P. A.; Bankier, A. A.

2026-10-21 radiology and imaging 10.64898/2026.10.19.26364791 medRxiv
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Background: Conventional performance metrics do not indicate whether artificial intelligence (AI)-platforms and radiologists are right or wrong on the same examinations, nor whether their non-agreement is more often beneficial or harmful. Objective: To develop, illustrate, and apply directional metrics quantifying non-agreement between radiologists and AI-platforms against a common reference standard, and to adapt a fragility-based framework for quantifying the statistical robustness of these metrics. Methods: We defined Positive Non-Agreement (PNA, AI-platform correct, radiologist incorrect), Negative Non-Agreement (NNA, radiologist correct, AI-platform incorrect), and Net Non-Agreement (NENA, their difference). Metrics were illustrated in three hypothetical scenarios of 1,000 examinations each and applied to three previously published AI-radiologist studies on pulmonary embolism and mammography. Bootstrap confidence intervals were calculated, and a reclassification fragility index (FI) quantified the minimum case reclassification needed to remove statistical support for NENA's direction. Results: In illustration, NENA was positive in two scenarios and negative in one. In the three published studies, NENA ranged from -4.18% to +10.74% and decreased consistently with increasing radiologist experience (junior residents, +6.27%; consultants, +1.45%), a gradient driven primarily by declining PNA with modest increase in NNA. The reclassification FI was defined for all three illustrative scenarios (range, 0.10%-1.70%) and for six of the seven comparisons from these studies (range, 0.34%-4.31%), but not for the weakest comparison, whose confidence interval for NENA included zero. Conclusions: PNA, NNA, and NENA provide a directional, case-level complement to conventional performance metrics for AI-radiologist non-agreement. The accompanying reclassification FI offers a statistically grounded, generalizable method for quantifying their robustness.

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Narrow Is Slow: CT-Derived Anatomic Isthmus 3 Width and Arrhythmogenic Substrate in Repaired Tetralogy of Fallot

Kosmopoulos, M.; Liskov, S.; Amir, R.; Berger, R. D.; Cedars, A.; Chehab, O.; Chrispin, J.; Fisher, S.; Fuller, S.; Fraint, H.; Armstrong, A. K.; Ziakas, I.; Aronis, K. N.

2026-10-19 cardiovascular medicine 10.64898/2026.10.16.26365751 medRxiv
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Background: Anatomic isthmus 3 (AI 3) is defined as the myocardium between the pulmonary valve annulus and the ventricular septal defect patch that persists after tetralogy of Fallot (ToF) repair. Ventricular tachycardia (VT) propagated through slow conducting AI 3 (SCAI 3) represents a significant cause of morbidity in ToF. There is an unmet need for non-invasive identification of SCAI 3 in patients with ToF. Objectives: To assess whether the anatomic features of AI 3 as derived from cardiac computed tomography (CT) can predict slow conduction velocity during EP study. Methods: This retrospective single-center study included patients with ToF who underwent an electrophysiologic study and had AI 3 width measured from the pre-procedure cardiac CT. All patients underwent programmed ventricular stimulation, and electroanatomic. Logistic regression was performed to assess the relationship between AI 3 width and the presence of SCAI 3. Results: Of 27 consecutive patients with ToF, twelve patients were found to have SCAI 3, and ten patients were found to have SCAI 3 mediated VT. The AI 3 was significantly narrower in patients with SCAI 3 compared to those with normal AI 3 conduction (18.4 +/- 6.6 mm vs. 29.2 +/- 9.0 mm; p = 0.001). An AI 3 width above 21.5 mm carried a negative predictive value of 80.0%. Conclusion: In adults with repaired ToF referred for electrophysiology study, a narrower CT-derived AI 3 width was associated with SCAI 3 identification. AI 3 width measured on a CT obtained before PV replacement could help guide invasive risk stratification.

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Morphometric Brain Networks at Ultra-Low Field: A First Assessment of Feasibility and Reliability

Karoui, H.; Bouke, N. J.; Cole, J. H.; Yeow, R. W.; Dick, F.; Razin, R.; Thomas, D. L.; Schroder, K. H.; Cash, D.; Bocchetta, M.; Williams, S. C.; Vasa, F.

2026-10-19 radiology and imaging 10.64898/2026.10.17.26365791 medRxiv
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Background: Ultra-low field (ULF) magnetic resonance imaging (MRI) offers accessible point-of-care neuroimaging, yet its capability to support multivariate network analyses remains understudied. Methods: We systematically evaluated the feasibility and reliability of Morphometric Similarity Networks (MSN) and Morphometric Inverse Divergence (MIND) networks derived from paired high-field (HF, 3T/1.5T) and ULF (64mT) scans in a primary cohort(N=23) and an independent replication cohort (N=19). We tested the impact of super-resolution processing, cortical parcellation granularity (Desikan-Killiany vs. Destrieux), and mesh resolution (fsnative vs. fsaverage5) on edge-level cross-scanner agreement (Lin's concordance correlation coefficient, CCC) and subject-level identifiability. Results: MIND networks demonstrated higher edge-level HF-ULF agreement (mean CCC = 0.95) and ULF reproducibility (mean CCC = 0.98) compared to MSNs (mean CCC = 0.86-0.87 and 0.91-0.94, respectively). In contrast, MSNs yielded higher subject-level differential identifiability across field strengths due to a broader distinction between within- and between-subject similarity. Reconstructing MIND networks on native high-resolution meshes (fsnative) maximised cross-scanner agreement, whereas coarser meshes and finer cortical parcellations enhanced individual network identifiability. Conclusions: Structural similarity networks can be reliably constructed from ULF MRI data. Optimal analytic choices depend on study objectives: MIND on native meshes maximises cross-scanner stability, whereas MSNs excel at preserving individual uniqueness, paving the way for globally scalable connectomic research.

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Neurochemical fingerprinting of the Alzheimers disease continuum using 7 T short-echo-time brain single voxel 1H-MRS.

Dell'Orco, A.; Göschel, L.; Riemann, L. T.; Aydin, S.; Flöel, A.; Tietze, A.; Scheel, M.; Fillmer, A.

2026-10-19 radiology and imaging 10.64898/2026.10.16.26365733 medRxiv
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Introduction: This study aimed to characterize the neurochemical profile of Alzheimer s disease (AD) continuum stages using proton magnetic resonance spectroscopy (1H-MRS) data for brain metabolites and macromolecules. We used Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS-DA) to classify diagnostic groups and assess feature importance. Methods: Our dataset consisted of 7 T short-echo time 1H-MRS spectra of the posterior cingulate cortex/precuneus of individuals diagnosed with AD (n = 27) or Mild Cognitive Impairment (MCI, n = 27) and Healthy Controls (HC, n = 31). Classification used 100-round Monte Carlo cross-validation based on metabolite concentrations and macromolecular peak intensities. Variable importance in projection (VIP) was assessed across classification models to identify the most relevant neurochemical features. The resulting metabolite rankings were compared with previous literature to evaluate their biological plausibility. Results: Classification was strongest for AD versus HC (AUC=0.88) and lower for comparisons involving MCI. Metabolites contributing most strongly to classification included myo-inositol, ascorbate, and choline-containing compounds, consistent with previous studies on AD-related neurochemical alterations. In addition, specific macromolecular components were identified as relevant features, suggesting a potential contribution of MM signals to the characterization of AD-related neurochemistry. Discussion: These findings support the use of short-echo-time 1H-MRS as a complementary tool for characterizing neurochemical changes in the AD continuum, with potential applications in disease characterization and monitoring, warranting validation in larger cohorts.

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Structural damage of the cervical spinal cord within and beyond the maximal compression area in mucopolysaccharidosis types I and VI

Nestrasil, I.; Lenglet, C.; Krasovec, I.; Mueller, B. A.; Ahmed, A.; Bondy, M. T.; Labounkova, I.; Chekouo, T.; Svatkova, A.; Whitley, C. B.; Labounek, R.

2026-10-21 radiology and imaging 10.64898/2026.10.21.26365852 medRxiv
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Background: Cervical spinal cord (CSC) compression and myelopathy are frequent, severe complications in mucopolysaccharidosis (MPS) types I and VI. Early detection is critical to prevent irreversible neurological deficits and preserve quality of life. This prospective study aimed to identify quantitative neuroimaging biomarkers of structural CSC damage and myelopathy in MPS I and VI. Methods: Structural and diffusion magnetic resonance imaging (MRI) of the CSC was analyzed in 17 MPS I patients, 3 MPS VI patients (19{+/-}7 years), and 19 case-matched healthy controls (20{+/-}7 years). CSC macrostructure (cross-sectional area, diameters) and microstructure (fractional anisotropy [FA], radial [RD], mean, axial diffusivities) were evaluated within and beyond the maximal compression areas. Results: MPS patients demonstrated reduced CSC cross-sectional area and anterior-posterior diameter at upper cervical levels, alongside widespread microstructural alterations (lower FA, higher RD) throughout the CSC versus controls (pFDR<0.05). Restricted foramen magnum space was associated with microstructural damage at lower cervical levels without overt macrostructural compression. Morphological and microstructural metrics were sensitive to CSC compression and myelopathy severity (pFDR<0.05). Lower CSC integrity correlated with more advanced growth retardation (p<0.001). Among patients receiving hematopoietic stem cell transplantation, earlier treatment correlated with preserved upper CSC morphology (p<0.05). Distinct neuroimaging phenotypes were observed across MPS genotypes (pFDR<0.05). Conclusions: CSC MRI provides candidate neuroimaging biomarkers for early detection and characterization of myelopathy in MPS I and VI. Structural damage extends beyond primary maximal compression areas, highlighting these markers for clinical monitoring and future therapeutic trials.

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Prevalence and Clinical Correlates of Coronary Perivascular Inflammation in an Asymptomatic Adult Primary Prevention Population: An Assessment of the CT-Derived Fat Attenuation Index Score (FAI-Score)

Stan, D.; Fu, J.; Ngov, M.; Doney, M.

2026-10-20 cardiovascular medicine 10.64898/2026.10.19.26364786 medRxiv
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Background: Coronary perivascular fat attenuation index score (FAI-Score) on coronary computed tomography angiography (CCTA) quantifies vascular inflammation and predicts cardiac mortality in symptomatic cohorts. However, its prevalence, anatomical distribution, and clinical correlates in asymptomatic primary prevention populations remain uncharacterized. Methods: In an IRB-approved prospective study across two clinical sites, 84 consecutive asymptomatic adults (mean age 53.7 {+/-} 8.6 years; 63.1% men) with no prior coronary artery disease underwent screening CCTA and comprehensive clinical, metabolic, and biomarker profiling. AI-standardized FAI-Score was quantified across three epicardial vessels (LAD, LCx, RCA). High and very high perivascular inflammation were pre-specified as any vessel [&ge;]75th and [&ge;]90th percentiles, respectively. Luminal stenosis and plaque were graded using CAD-RADS 2.0. Results: Elevated FAI-Score ([&ge;]75th percentile) was present in 42.9% of participants (36/84; 95% CI 32.8% - 53.5%), with 17.9% (15/84; 95% CI 11.1% - 27.4%) exhibiting very high inflammation ([&ge;]90th percentile). Multi-vessel inflammation was identified in 17.9% (15/84), with the RCA most frequently involved ([&ge;]90th percentile in 13.1%). Standard circulating biomarkers, including ApoB, non-HDL-C, HbA1c, and PREVENT-ASCVD 10-year risk showed no association with binary inflammation. Systemic hs-CRP (median 0.8 mg/L) exhibited an inverse correlation with maximum vessel FAI-Score (Spearman {rho}=-0.27, p=0.014). Men demonstrated higher rates of elevated FAI-Score than women (52.8% vs. 25.8%, p=0.016; [&ge;]90th percentile: 26.4% vs. 3.2%, p=0.007). Strikingly, 46.2% (30/65) of participants with normal luminal anatomy (CAD-RADS 0) and 47.2% (25/53) with zero plaque burden harbored elevated FAI-Score; all 15 individuals with very high FAI-Score had CAD-RADS 0 (Fisher's exact p=0.018). Body mass index was the sole secondary correlate surviving false discovery rate correction (AUC = 0.71, p=0.001, all-test FDR q=0.028). Regularized multivariable models showed modest out-of-sample discrimination for FAI-Score elevation (cross-validated AUC = 0.71). Conclusions: Coronary perivascular inflammation is common among asymptomatic adults and frequently uncouples from structural plaque and luminal stenosis. Routine circulating biomarkers and clinical risk calculators fail to identify inflamed vessels, highlighting FAI-Score as an independent dimension of primary cardiovascular risk assessment.

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Concussion, Attention, and Mental Health: A Brain Network Study in Youth (CAMBY) - Study Protocol

Scratch, S.; Gill, P. K.; Hickling, A.; Irvin, A.; Zamyadi, R.; Parimoo, S.; Johnston, P. R.; Davis, A. L.; Ibrahim, G. M.; Dunkley, B. T.; Wheeler, A. L.

2026-10-20 neurology 10.64898/2026.10.14.26365111 medRxiv
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BACKGROUND: One in three adolescents with a concussion history report experiencing long-lasting somatic, sleep, emotional, and/or cognitive disturbances (persisting symptoms after concussion (PSaC)). Cognitive difficulties, such as attentional problems, are common symptoms and can interfere with ongoing development. Clinically, psychiatric symptoms also present in youth with PSaC. A concussion causes diffuse functional and microstructural alterations to neural networks. To develop targeted treatments for PSaC (e.g., neurostimulation), we need to understand how and where structural alterations and neural dysfunction intersect to cause long-lasting symptoms. OBJECTIVES: 1) Identify functional and microstructural properties in intrinsic connectivity networks, as well as neuropsychological outcomes, that differentiate adolescents with concussion with PSaC from those who do not have PSaC. 2) Determine whether neural activity within intrinsic connectivity networks mediates the relationship between network microstructure and specific neuropsychological features in adolescents with concussion. METHODS: CAMBY is a prospective study of adolescents aged 12 to 18 years with a history of concussion. Participants are allocated based on recovery status (PSaC vs. No-PSaC (recovered controls)). Advanced structural (magnetic resonance imaging; MRI) and functional (magnetoencephalography; MEG) neuroimaging and neuropsychological measures will be collected one month or more after concussion. Microstructural and functional features will be computed within intrinsic connectivity networks, then compared between PSaC and recovered control groups and related to symptom domains and neuropsychological profiles. IMPACT: This will be the first study to integrate MRI, MEG, and neuropsychology in adolescents with PSaC to identify disrupted networks underlying PSaC. This observational study is a necessary step towards future clinical trials that accurately target promising therapeutic neurostimulation protocols.

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Deep learning-based electrocardiographic differentiation of Takotsubo syndrome from acute anterior myocardial infarction: explainability, human-AI interaction, and a utilization bias hypothesis

Kagawa, E.; Kato, M.; Hidaka, T.; Kunita, E.; Hironobe, N.; Matsui, S.; Kobayashi, Y.; Uotani, Y.; Teramoto, T.; Yoshii, K.; Okumoto, T.; Tani, M.; Dote, K.

2026-10-19 cardiovascular medicine 10.64898/2026.10.15.26365116 medRxiv
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Background: Artificial intelligence (AI) may improve electrocardiographic differentiation of Takotsubo syndrome from acute anterior ST-segment elevation myocardial infarction (STEMI), but its impact on human diagnostic performance, the added value of visual explanations, and differences by reader background and experience remain uncertain. Methods: Using 12-lead electrocardiogram (ECG) images from two hospitals, we developed and externally validated an ensemble of three deep learning models after self-supervised pretraining and fine-tuning. The diagnostic task used ECGs recorded within 14 days after symptom onset, regardless of reperfusion status. We conducted a four-phase reader study. Phases 1-3 compared unaided interpretation, a reference sheet, and additional AI assistance. In Phase 4, readers evaluated a new ECG set after randomization to reference-sheet support alone, with AI predictions, or with AI predictions plus gradient-weighted class activation mapping (Grad-CAM) heatmaps. Diagnostic correctness was analyzed using generalized linear mixed-effects models. Exploratory analyses examined differences by cardiologist status and experience. Results: Development and external-validation cohorts, including healthy controls, comprised 832 and 95 participants, respectively. For Takotsubo-STEMI discrimination, external-validation accuracy was 0.914, with areas under the receiver operating characteristic and precision-recall curves of 0.970 and 0.984. Seventy healthcare providers completed the reader study. The estimated probability of correct diagnosis increased from 0.632 without assistance to 0.864 with AI assistance (odds ratio [OR], 3.71; P<0.001). In randomized Phase 4, AI assistance improved accuracy vs reference-sheet support alone (OR, 4.28; 95% CI, 3.08-5.95; P<0.001), and Grad-CAM provided additional benefit (OR, 1.53; 95% CI, 1.04-2.25; P=0.033). Exploratory analyses showed greater improvement among less experienced readers; with AI assistance, non-cardiologists outperformed cardiologists. AI-assisted readers remained less accurate overall than the model alone. Conclusions: An ECG image-based ensemble differentiated Takotsubo syndrome from anterior STEMI and improved reader accuracy. Visual explanations provided additional benefit, while experience-related differences highlight the importance of effective human-AI interaction.