Imaging Mismatch Research Articles

Computed tomography and structured light imaging guided orthopedic navigation puncture system: effective reduction of intraoperative image drift and mismatch.

Image-guided surgical navigation systems are widely regarded as the benchmark for computer-assisted surgical robotic platforms, yet a persistent challenge remains in addressing intraoperative image drift and mismatch. It can significantly impact the accuracy and precision of surgical procedures. Therefore, further research and development are necessary to mitigate this issue and enhance the overall performance of these advanced surgical platforms. The primary objective is to improve the precision of image guided puncture navigation systems by developing a computed tomography (CT) and structured light imaging (SLI) based navigation system. Furthermore, we also aim to quantifying and visualize intraoperative image drift and mismatch in real time and provide feedback to surgeons, ensuring that surgical procedures are executed with accuracy and reliability. A CT-SLI guided orthopedic navigation puncture system was developed. Polymer bandages are employed to pressurize, plasticize, immobilize and toughen the surface of a specimen for surgical operations. Preoperative CT images of the specimen are acquired, a 3D navigation map is reconstructed and a puncture path planned accordingly. During surgery, an SLI module captures and reconstructs the 3D surfaces of both the specimen and a guiding tube for the puncture needle. The SLI reconstructed 3D surface of the specimen is matched to the CT navigation map via two-step point cloud registrations, while the SLI reconstructed 3D surface of the guiding tube is fitted by a cylindrical model, which is in turn aligned with the planned puncture path. The proposed system has been tested and evaluated using 20 formalin-soaked lower limb cadaver specimens preserved at a local hospital. The proposed method achieved image registration RMS errors of 0.576 ± 0.146 mm and 0.407 ± 0.234 mm between preoperative CT and intraoperative SLI surface models and between preoperative and postoperative CT surface models. In addition, preoperative and postoperative specimen surface and skeletal drifts were 0.033 ± 0.272 mm and 0.235 ± 0.197 mm respectively. The results indicate that the proposed method is effective in reducing intraoperative image drift and mismatch. The system also visualizes intraoperative image drift and mismatch, and provides real time visual feedback to surgeons.

Thrombolysis in wake-up stroke based on MRI mismatch

ObjectivesWake-up stroke (WUPS) patients can be selected to intravenous thrombolysis (IVT) treatment based on the Magnetic Resonance Imaging (MRI) mismatch concept. However, recent studies suggest the introduction of modified MRI mismatch criteria, allowing IVT in WUPS patients with a partial mismatch. Material and methodsWUPS patients treated with IVT in the NOR-TEST trial and consecutively thereafter at Stavanger University Hospital were included in this study. Patient selection for treatment was performed based on the clinical presentation and the MRI DWI/FLAIR mismatch criteria. MRI examinations were reassessed according to the modified DWI-FLAIR mismatch criteria, allowing partial mismatch. Improvement in NIHSS and mRS at 3 months were used to analyze clinical outcome, and the rate of intracranial hemorrhage (ICH) to analyze safety. Results78 WUPS patients were treated with IVT. Only 68 of these patients were independent pre-stroke and included in the clinical analysis. When reassessing the MRI examinations, 41 (60 %) were rated as DWI/ FLAIR mismatch, 14 (21 %) as partial mismatch and 13 (19 %) as match. The results show that the patient groups had a mRS score 0–1 at 3 months measured as primary outcome to respectively 27 (65.9 %), 11 (78.6 %) and 8 (61.5 %); (P = 0.629). The mismatch group showed the best clinical improvement (3-points NIHSS reduction, p = 0.005). No ICH was seen in any of the groups. ConclusionOur study extended the mismatch concept in clinical praxis to treat WUPS patients with partial mismatch, showing the best clinical outcome in the mismatch group.

A novel deformation measurement method for rotating blade based on PSO-ILS image correlation matching and mismatch correction

Abstract Aiming at the problem of small measurement range and difficult measurement of traditional contact sensor method in the rotating state of aero-engine blades, this paper proposes a novel deformation measurement method for rotating blade based on image correlation matching and mismatch correction. Firstly, a Particle Swarm Optimization-Iterative Local Search image intelligent matching algorithm is proposed, which effectively balances global search and local optimization, and the image matching displacement accuracy reaches 10−3 pixel. Secondly, a mismatch point detection method based on multi-scale local Root Mean Square is proposed, and the high-precision detection of mismatch points is realized by considering the influence of local structure. Finally, through the hierarchical refinement of the sub-pixel level mismatch point correction method, the mismatch point is corrected in the two iterative stages of global search and local optimization. The corrected mismatch point response value K is reduced by 99% compared with that before correction, which further improves the accuracy of deformation field calculation. In the experiment, the deformation of the rotating blade of 4500 RPM is measured, which proves that the image intelligent matching algorithm and the deformation field calculation method proposed in this paper can provide new methods and technical support for the accurate measurement of the blade surface deformation.

Endovascular thrombectomy in wake-up stroke guided by arterial spin-labeling and fluid-attenuated inversion recovery versus diffusion-weighted imaging mismatch on MRI.

This purpose of this study is to investigate the effectiveness and safety of utilizing the arterial spin-labeling (ASL) combined with diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) combined with DWI double mismatch in the endovascular treatment of patients diagnosed with wake-up stroke (WUS). In this single-center trial, patients diagnosed with WUS underwent thrombectomy if acute ischemic lesions were observed on DWI indicating large precerebral circulation occlusion. Patients with no significant parenchymal hypersignal on FLAIR and ASL imaging showing a hypoperfusion tissue to infarct core volume ratio of at least 1.2 were included. The participants were divided into groups receiving endovascular thrombectomy plus medical therapy or medical therapy alone, based on their subjective preference. Functional outcomes were assessed using the ordinal score on the modified Rankin scale (mRs) at 90 days, along with the rate of functional independence. In this study, a total of 77 patients were included, comprising 38 patients in the endovascular therapy group and 39 patients in the medical therapy group. The endovascular therapy group exhibited more favorable changes in the distribution of functional prognosis measured by mRs at 90 days, compared to the medical therapy group (adjusted common odds ratio, 3.25; 95% CI, 1.03 to 10.26; P < 0.01). Additionally, the endovascular therapy group had a higher proportion of patients achieving functional independence (odds ratio, 4.0; 95% CI, 1.36 to 11.81; P < 0.01). Importantly, there were no significant differences observed in the incidence of intracranial hemorrhage or mortality rates between the two groups. Guided by the ASL-DWI and FLAIR-DWI double mismatch, endovascular thrombectomy combined with standard medical treatment appears to yield superior functional outcomes in patients with WUS and large vessel occlusion compared to standard medical treatment alone.

Enhancing Image Alignment in Time-Lapse-Ground-Penetrating Radar through Dynamic Time Warping

Ground-penetrating radar (GPR) is a rapid and non-destructive geophysical technique widely employed to detect and quantify subsurface structures and characteristics. Its capability for time lapse (TL) detection provides essential insights into subsurface hydrological dynamics, including lateral flow and soil water distribution. However, during TL-GPR surveys, field conditions often create discrepancies in surface geometry, which introduces mismatches across sequential TL-GPR images. These discrepancies may generate spurious signal variations that impede the accurate interpretation of TL-GPR data when assessing subsurface hydrological processes. In responding to this issue, this study introduces a TL-GPR image alignment method by employing the dynamic time warping (DTW) algorithm. The purpose of the proposed method, namely TLIAM–DTW, is to correct for geometric mismatch in TL-GPR images collected from the identical survey line in the field. We validated the efficacy of the TLIAM–DTW method using both synthetic data from gprMax V3.0 simulations and actual field data collected from a hilly, forested area post-infiltration experiment. Analyses of the aligned TL-GPR images revealed that the TLIAM–DTW method effectively eliminates the influence of geometric mismatch while preserving the integrity of signal variations due to actual subsurface hydrological processes. Quantitative assessments of the proposed methods, measured by mean absolute error (MAE) and root mean square error (RMSE), showed significant improvements. After performing the TLIAM–DTW method, the MAE and RMSE between processed TL-GPR images and background images were reduced by 96% and 78%, respectively, in simple simulation scenarios; in more complex simulations, MAE declined by 27–31% and RMSE by 17–43%. Field data yielded reductions in MAE and RMSE of &gt;82% and 69%, respectively. With these substantial improvements, the processed TL-GPR images successfully depict the spatial and temporal transitions associated with subsurface lateral flows, thereby enhancing the accuracy of monitoring subsurface hydrological processes under field conditions.

Imaging Mismatch of Nail in the Eyeball: What’s next?

Introduction : A retained foreign body (FB) can lead to severe complications, the most devastating of which is eye loss. We present a discrepancy of imaging that resulted in a dilemma in the approach management of a mixed global-adnexal FB case.&#x0D; Case Illustration : A 31-year-old man came to the emergency room with blurry vision for 1.5 hours after a nail hit his right eye (RE). The visual acuity of RE is light perception. Ophthalmological examination revealed a central Y-shaped full-thickness corneal laceration with iris and vitreous prolapse. The lens appeared cloudy, and the posterior segment was difficult to assess. Imaging showed a foreign metal object asa nail in the oculi to intraconal without penetration to the orbital wall. He was planned to undergo FB extraction with corneal laceration repair and aspiration of lens mass irrigation. However, the nail was hard to find intraoperatively because the vitreous and choroid kept coming out. Hence evisceration with DFG was performed. The nail was found more posteriorly and attached to the bone.&#x0D; Discussion : While primary repair is the standard practice for open globe injury, managing retained intraocular metallic foreign bodies is controversial. Imaging such as CT scans can help determine the location of FB and approach management. In this case, imaging showed the FB was in the iris plane and not penetrating the orbital wall, so primary repair and FB extraction were planned.&#x0D; Conclusion : The imaging may not always be accurate in determining the exact location of FB, and the surgical approach may need to be adjusted accordingly.

Abstract TP140: Effect of MR-Guided Perfusion Imaging Mismatch Profiles Within 6 Hours on Endovascular Thrombectomy Outcomes

Background: The treatment of acute ischemic stroke (AIS) aims to achieve early vascular recanalization and reperfusion of the penumbra. However, the effect of early penumbral imaging within 6 hours on clinical outcomes remains unclear. Objective: The objective of this study was to determine the effect of magnetic resonance-guided (MR-guided) perfusion imaging within 6 hours after symptom onset on endovascular thrombectomy outcomes in AIS patients. Methods: We prospectively collected the clinical information of consecutive AIS patients undergoing endovascular thrombectomy based on MR-guided perfusion imaging within 6 hours after symptom onset from AISRNA and EVTRNA studies. The primary outcome was defined as the poor outcome (mRS &gt; 2 within 90 days). The perfusion-weighted imaging/diffusion-weighted imaging (PWI/DWI) mismatch was assessed by an automated software. Results: We enrolled 84 patients (25 in the mismatch ≤ 1.8 group and 59 in the mismatch &gt; 1.8 group). Significant difference was found between the mismatch&gt;1.8 group and the mismatch≤1.8 group for the incidence of disabling stroke (mRS &gt; 2) within 90 days (40.7% vs. 68.0%, OR: 3.099, 95% CI: 1.154-8.323, P =0.025). Intracranial hemorrhage occurred in 8 patients (13.6%) in the mismatch &gt; 1.8 group and 10 patients in the mismatch ≤ 1.8 group (40.0%) (P = 0.010). The risk of severe cerebral edema was 2/59 (3.4%) vs. 7/25 (28.0%) (P = 0.004). These findings remained stable after adjustment. Conclusion: MR-guided perfusion imaging mismatch profiles within 6 hours after symptom onset may be feasible to improve clinical outcomes and reduce clinically ineffective reperfusion after endovascular thrombectomy.

Abstract TP207: Endovascular Treatment in the Late Time Window: Strict Perfusion Imaging Screening Criteria in Case Selection

Background and purpose: Clinical-imaging mismatch or perfusion imaging mismatch criteria per DAWN (Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) or DEFUSE-3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke), respectively were recommended for case selection for endovascular treatment (EVT) of acute ischemic stroke (AIS) in the late time window outside 6 hours of stroke onset. We aimed to compare the clinical functional outcomes in EVT patients with and without strict perfusion imaging screening criteria in the late time window. Methods: AIS patients with anterior circulation large vessel occlusion (LVO) presenting within 6 to 24h hours after symptom onset were selected from a retrospectively collected thrombectomy cohort database (RESTORE). According to the imaging criteria of DAWN and DEFUSE-3, we compared proportions of patients with a favorable functional outcome (defined as a modified Rankin Scale [mRS] score of 0-2) at 90 days between the DAWN or DEFUSE-3 patients (D/D) and the non-DAWN or DEFUSE-3 (non-D/D) patients. Results: Among 265 adult patients with anterior circulation LVO who received EVT within 6 to 24 hours after symptom onset, 142 patients met either DAWN or DEFUSE-3 imaging criteria. D/D group independently predicted favorable functional outcome at 90 days (50.7% vs. 35.0%, aOR 0.514; 95% CI 0.273-0.966, p=0.039) adjusted for age, sex, previous stroke, hypertension, atrial fibrillation, coronary heart disease, pre-EVT collateral score, successful recanalization, onset to CT time. Conclusions: In AIS patients with anterior circulation LVO in the late time window, our real world data support the guideline that DAWN or DEFUSE-3 imaging criteria are strongly recommended for EVT case selection.

Comparison between MRI FLAIR vascular hyperintensity-DWI mismatch and perfusion based triage for thrombectomy in the late time window.

The clinical impact of patient selection using FLAIR vascular hyperintensity (FVH)-diffusion-weighted imaging (DWI) mismatch for endovascular thrombectomy (EVT) in patients who have been symptomatic for over 6 h remains unclear. Herein, a retrospective study was conducted to compare the inter-rater reliability and clinical outcomes of patients selected for thrombectomy based on FVH-DWI mismatch with perfusion. Patients with anterior-circulation large-vessel occlusion selected simultaneously with MRI and perfusion imaging in the late time window from a single-center retrospective study were categorized into EVT-applicable (FVH-DWI mismatch on MRI or perfusion imaging meeting the DEFUSE3 standards) and EVT-inapplicable groups based on MRI and perfusion imaging. The primary outcome was the 90-day functional independence rate. Safety outcomes encompassed symptomatic intracranial hemorrhage and mortality in 90 days. We assessed the consistency of the two profiles and compared the differences in functional independence rates of EVT patients among the EVT-applicable groups determined by MRI and perfusion. A total of 130 patients were enrolled, of which 114 were classified into the EVT-applicable group after triaging using MRI images. In this group, 96 patients underwent EVT, with 53 of them (55.2%) achieving functional independence. A total of 110 patients were divided into EVT-applicable group based on perfusion, among which 92 underwent EVT, with 49 of them (53.2%) achieving functional independence. The consistency of identifying EVT indication was moderate between two groups (κ = 0.42, 95% CI, 0.17-0.67). The functional independence rate was comparable between patients in the two EVT-applicable groups based on the two methods (55.2% vs. 53.2%, p = 0.789). MRI triaging based on FVH-DWI mismatch showed moderate inter-rater reliability compared with perfusion-based triage and comparable efficacy in predicting clinical outcomes after EVT.

Improvement of Perceived Depth Degradation by Motion Parallax in Binocular Stereopsis With Left-Right Retinal Image Mismatch

Improvement of Perceived Depth Degradation by Motion Parallax in Binocular Stereopsis With Left-Right Retinal Image Mismatch

Do we love celebrity endorsers? The joint impacts of consumers' need for status, celebrity’s star power and image congruence on celebrity endorsement effectiveness

PurposeThe current study aims to examine the joint impact of consumers' need for status (NFS), celebrity's star power and consumer-celebrity image match on consumers' attitudes toward the celebrity endorsement.Design/methodology/approachA factorial design was employed to test the research model. Consumer-celebrity image match was manipulated, and consumers' NFS and celebrity's star power was captured using existing measurement scales. A total of 365 responses were collected via Qualtrics. Hayes's (2013) PROCESS procedure was used to analyze the data and test hypotheses.FindingsResults indicate that consumers with high (vs low) NFS have more favorable attitudes toward the endorsed brand. More importantly, consumers high in NFS, in an endorsement where celebrity-consumer image matches, have more favorable attitudes toward the brand endorsed by a celebrity with more (vs less) star power. In contrast, in an endorsement where celebrity-consumer image mismatches, they react the same regardless of the endorser's star power.Practical implicationsThis study offers suggestions to hospitality marketing professionals in strategically using celebrity endorsers in their marketing campaigns and strategies that allows firms to further formulate positive and enduring brand images while encouraging favorable consumer behaviors.Originality/valueWhile most hospitality studies have focused on the traits of celebrity endorsers, little attention has been paid to the impact of consumers' characteristics on celebrity endorsement. This study advances the growing literature on hospitality celebrity endorsement by providing empirical evidence to delineate the relationship among celebrities, endorsed brands and consumers.

Predicting DWI-FLAIR mismatch on NCCT: the role of artificial intelligence in hyperacute decision making.

The presence of diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) mismatch was used to determine eligibility for intravenous thrombolysis in clinical trials. However, due to the restricted availability of MRI and the ambiguity of image assessment, it is not widely implemented in clinical practice. A total of 222 acute ischemic stroke patients underwent non-contrast computed tomography (NCCT), DWI, and FLAIR within 1 h of one another. Human experts manually segmented ischemic lesions on DWI and FLAIR images and independently graded the presence of DWI-FLAIR mismatch. Deep learning (DL) models based on the nnU-net architecture were developed to predict ischemic lesions visible on DWI and FLAIR images using NCCT images. Inexperienced neurologists evaluated the DWI-FLAIR mismatch on NCCT images without and with the model's results. The mean age of included subjects was 71.8 ± 12.8 years, 123 (55%) were male, and the baseline NIHSS score was a median of 11 [IQR, 6-18]. All images were taken in the following order: NCCT - DWI - FLAIR, starting after a median of 139 [81-326] min after the time of the last known well. Intravenous thrombolysis was administered in 120 patients (54%) after NCCT. The DL model's prediction on NCCT images revealed a Dice coefficient and volume correlation of 39.1% and 0.76 for DWI lesions and 18.9% and 0.61 for FLAIR lesions. In the subgroup with 15 mL or greater lesion volume, the evaluation of DWI-FLAIR mismatch from NCCT by inexperienced neurologists improved in accuracy (from 0.537 to 0.610) and AUC-ROC (from 0.493 to 0.613). The DWI-FLAIR mismatch may be reckoned using NCCT images through advanced artificial intelligence techniques.

Radiometric Normalization Using a Pseudo−Invariant Polygon Features−Based Algorithm with Contemporaneous Sentinel−2A and Landsat−8 OLI Imagery

As sensor parameters and atmospheric conditions create uncertainties for at−sensor radiation detection, radiometric consistency among satellite images is difficult to achieve. Relative radiometric normalization is a method that can improve multi−image consistency with accurate pseudo−invariant features (PIFs), especially over large areas or long time series satellite images. Although there are algorithms that manually or automatically select PIFs, the spatial mismatch of satellite images can affect PIF extraction, particularly with artificial pixels. To alleviate this problem, we proposed to use Landsat−8 OLI as the reference image and Sentinel−2A as the subject image, to apply pseudo−invariant features−based algorithms with polygon features through the single−band and multiple−band regression. Compared to pseudo−invariant point features, hyperspectral library, and histogram matching approaches, the results demonstrate the superiority of the proposed algorithms with correlation coefficients of 0.9948 and 0.9945, and an RMSE of 0.0097 and 0.0095 with multiple− and single−band regression, respectively. We also found more accurate linear fitting and better shape matching through band scattering and reflectance frequency analysis. The proposed algorithms are a significant improvement in radiometric normalization, within artificial pixels, achieving spectral signature consistency.

Mechanical thrombectomy decision making and prognostication: Stroke treatment Assessments prior to Thrombectomy In Neurointervention (SATIN) study

BackgroundMechanical thrombectomy (MT) is the standard-of-care treatment for stroke patients with emergent large vessel occlusions. Despite this, little is known about physician decision making regarding MT and prognostic accuracy.MethodsA prospective...

3D–2D image registration in the presence of soft-tissue deformation in image-guided transbronchial interventions

Purpose. Target localization in pulmonary interventions (e.g. transbronchial biopsy of a lung nodule) is challenged by deformable motion and may benefit from fluoroscopic overlay of the target to provide accurate guidance. We present and evaluate a 3D–2D image registration method for fluoroscopic overlay in the presence of tissue deformation using a multi-resolution/multi-scale (MRMS) framework with an objective function that drives registration primarily by soft-tissue image gradients. Methods. The MRMS method registers 3D cone-beam CT to 2D fluoroscopy without gating of respiratory phase by coarse-to-fine resampling and global-to-local rescaling about target regions-of-interest. A variation of the gradient orientation () similarity metric (denoted ) was developed to downweight bone gradients and drive registration via soft-tissue gradients. Performance was evaluated in terms of projection distance error at isocenter (PDEiso). Phantom studies determined nominal algorithm parameters and capture range. Preclinical studies used a freshly deceased, ventilated porcine specimen to evaluate performance in the presence of real tissue deformation and a broad range of 3D–2D image mismatch. Results. Nominal algorithm parameters were identified that provided robust performance over a broad range of motion (0–20 mm), including an adaptive parameter selection technique to accommodate unknown mismatch in respiratory phase. The metric yielded median PDEiso = 1.2 mm, compared to 6.2 mm for conventional Preclinical studies with real lung deformation demonstrated median PDEiso = 1.3 mm with MRMS + registration, compared to 2.2 mm with a conventional transform. Runtime was 26 s and can be reduced to 2.5 s given a prior registration within ∼5 mm as initialization. Conclusions. MRMS registration via soft-tissue gradients achieved accurate fluoroscopic overlay in the presence of deformable lung motion. By driving registration via soft-tissue image gradients, the method avoided false local minima presented by bones and was robust to a wide range of motion magnitude.

Imaging mismatch between Alberta Stroke Program Early CT Score and perfusion imaging may be a good variable for endovascular treatment.

Some patients with acute large vessel occlusion (LVO) presented imaging mismatch, low Alberta Stroke Program Early CT Score (ASPECTS) with small ischemic core, or high ASPECTS with large ischemic core. The study was designed to explore whether patients with imaging mismatch could benefit from endovascular treatment (EVT). We retrospectively reviewed patients with LVO treated with EVT in our center from March 2018 to Jul 2020. Patients were divided into three groups, imaging mismatch, small ischemic core, and large ischemic core groups. Pooled analyses based on stroke onset to treatment time were done. Multivariate regression analysis was performed to explore the factors for good outcomes. Sixty-eight of 419 patients with LVO presented with imaging mismatch, and 35 of those (51%) achieved good outcomes after EVT at 90-day. No significant differences were noted in good outcomes and symptomatic intracranial hemorrhage (sICH) between patients with imaging mismatch and small ischemic core. Compared with large ischemic core, patients with imaging mismatch presented lower risk of sICH (95% confidence interval (CI) 0.04-0.75, p = 0.011) within 6 h and higher proportion of good outcomes (95% CI 0.37-0.82, p = 0.002) at 6 to 24 h. Baseline NIHSS (odds ratio (OR) = 0.91, 95% CI 0.88-0.95)), ASPECTS (OR = 1.14, 95% CI 1.01-1.29), ischemic core (OR = 0.99, 95% CI 0.98-1.00), and sICH (OR = 61.61, 95% CI 8.09-461.32) were associated with good outcomes. Patients with imaging mismatch treated within 24 h could benefit from EVT and without increasing the risk of sICH. • Patients with imaging mismatch between ASPECTS and ischemic core could achieve good outcomes after endovascular treatment. • Compared with large ischemic core, patients with imaging mismatch presented lower risk of symptomatic hemorrhage within 6 h and higher proportion of good outcomes within 6-24 h. • Baseline NIHSS score, ASPECTS, ischemic core, and symptomatic intracranial hemorrhage were associated with good outcomes.

Mechanical Thrombectomy in the Late Presentation of Anterior Circulation Large Vessel Occlusion Stroke: A Guideline From the Society of Vascular and Interventional Neurology Guidelines and Practice Standards Committee.

Recent clinical trials investigating endovascular therapy (EVT) in the extended time window have opened new treatment paradigms for late-presenting patients with large vessel occlusion (LVO) stroke. The aim of this guideline is to provide up to date recommendations for the diagnosis, selection, and medical or endovascular treatment of patients with LVO presenting in the extended time window. The Society of Vascular & Interventional Neurology (SVIN) Guidelines and Practice Clinical Standards (GAPS) committee assembled a writing group and recruited interdisciplinary experts to review and evaluate the current literature. Recommendations were assigned by the writing group using the SVIN-GAPS Class of Recommendation/Level of Evidence algorithm and SVIN GAPS guideline format. The final guideline was approved by all members of the writing group, the GAPS committee, and the SVIN board of directors. Literature review yielded three high quality randomized trials and several observational studies that have been extracted to derive the enclosed summary recommendations. In patients with LVO presenting in the 6-to-24-hour window, and with clinical imaging mismatch as defined by the DAWN and DEFUSE 3 studies, EVT is recommended. Non contrast CT can be used to evaluate infarct size as sole imaging modality for patient selection, particularly when access to CT perfusion or MRI is limited, or if their performance would incur substantial delay to treatment. In addition, several clinical questions were reviewed based on the available evidence and consensus grading. These guidelines provide practical recommendations based on recent evidence on the diagnosis, selection, and treatment of patients with LVO stroke presenting in the extended time window.

DWI-FLAIR Mismatch in Stroke: “P.S.” (Partial Strategic Concept) for Clinical Practice

Recent studies have shown that diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) MRI (DWI-FLAIR) mismatch is useful for thrombolytic treatment decisions in acute ischemic stroke. However, the role of partial mismatch in strategic locations among patients with evolving stroke has not been described before. Partial imaging mismatch involving strategic locations might indicate reversible ischemia, enabling thrombolysis even in those patients presenting in the extended time windows. In this report, we describe the partial strategic concept of DWI-FLAIR mismatch with case examples.

Plasma mid-regional pro-adrenomedullin: A biomarker of the ischemic penumbra in hyperacute stroke.

Reperfusion therapy has improved the outcomes of ischemic stroke but also emphasized the importance of ischemic penumbra. However, blood biomarkers are currently unavailable for this region. Adrenomedullin (ADM) is a neuroprotective peptide, secreted in a compensatory response to brain ischemia. We thus investigated whether an increase in mid-regional pro-ADM (MR-proADM), a stable peptide fragment of the ADM precursor, could act as a biomarker by predicting the ischemic penumbra in hyperacute ischemic stroke (HAIS). We prospectively enrolled consecutive HAIS patients (n=119; median age, 77 years; male, 59.7%) admitted to our institutes from July 2017 to March 2019 and evaluated plasma MR-proADM levels within 4.5h of onset. MR-proADM levels in HAIS were compared to healthy controls (n=1298; median age, 58 years; male, 33.2%) in the Japan Multi-Institutional Collaborative Cohort Study from 2013 to 2017. Furthermore, we evaluated whether MR-proADM levels were associated with the penumbra estimated by clinical-diffusion mismatch (CDM) (National Institute of Health Stroke Scale [NIHSS] ≥8, diffusion ischemic core volume ≤25 ml), or magnetic resonance angiography-diffusion-weighted imaging mismatch (MDM) (NIHSS ≥5, a proximal vessel occlusion with core volume ≤25 ml, or a proximal vessel stenosis/distal vessel occlusion with core volume ≤15 ml). In a case-control study, multivariate logistic analysis showed a significant association between HAIS and MR-proADM ≥0.54 nmol/L (adjusted odds ratio, 7.92 [95% CI, 4.17-15.02], p < 0.001). Though MR-proADM levels in HAIS did not correlate with the ischemic core volume (rs =0.09, p=0.348), they were higher in HAIS with CDM (n=34; 0.81 vs. 0.61 nmol/L, p < 0.001) or MDM (n=26; 0.83 vs. 0.62 nmol/L, p=0.002). These differences remained significant after adjusting baseline factors (adjusted odds ratio, 4.06 [95% CI, 1.31-12.55], p = 0.015 and 4.65 [1.35-16.11], p = 0.015, respectively). Plasma MR-proADM is elevated in HAIS, especially in those with a substantial penumbra, suggesting potential as a blood biomarker in this region.

Robust graph fusion and recognition framework for fingerprint and finger‐vein

The human finger is the essential carrier of biometric features. The finger itself contains multi-modal traits, including fingerprint and finger-vein, which provides convenience and practicality for finger bi-modal fusion recognition. The scale inconsistency and feature space mismatch of finger bi-modal images are important reasons for the fusion effect. The feature extraction method based on graph structure can well solve the problem of feature space mismatch for the finger bi-modalities, and the end-to-end fusion recognition can be realised based on graph convolutional neural networks (GCNs). However, this fusion recognition strategy based on GCNs still has two urgent problems: first, lack of stable and efficient graph fusion method; second, over-smoothing problem of GCNs will lead to the degradation of recognition performance. A novel fusion method is proposed to integrate the graph features of fingerprint (FP) and finger-vein (FV). Furthermore, we analyse the inner relationship between the information transmission process and the over-smoothing problem in GCNs from an optimisation perspective, and point out that the differentiated information between neighbouring nodes decreases as the number of layers increases, which is the direct reason for the over-smoothing problem. A modified deep graph convolution neural network is proposed, aiming to alleviate the over-smoothing problem. The intuition is that the differentiated features of the nodes should be properly preserved to ensure the uniqueness of the nodes themselves. Thus, a constraint term to the objective function of the GCN is added to emphasise the differentiation features of the nodes themselves. The experimental results show that the proposed fusion method can achieve more satisfied performance in finger bi-modal biometric recognition, and the proposed constrained GCN can well alleviate the problem of over-smoothing.