Reconstruction Time Research Articles

Computationally efficient collimator-detector response compensation in high energy SPECT using 1D convolutions and rotations.

Modeling of the collimator-detector response (CDR) in SPECT reconstruction enables improved resolution and accuracy, and is thus important for quantitative imaging applications such as dosimetry. The implementation of CDR modeling, however, can become a computational bottleneck when there are substantial components of septal penetration and scatter in the acquired data, since a direct convolution-based approach requires large 2D kernels. This work proposes a 1D convolution and rotation-based CDR model that reduces reconstruction times but maintains consistency with models that employ 2D convolutions. To enable open-source development and use of these models in image reconstruction, we release a SPECTPSFToolbox repository for the PyTomography project on GitHub. A 1D/rotation-based CDR model was formulated and subsequently fit to Monte Carlo point source data representative of Lu-177, I-131, and Ac-225 imaging. Computation times of (i) the proposed 1D/rotation-based model and (ii) a traditional model that uses 2D convolutions were compared for typical SPECT matrix sizes. Both CDR models were then used in the reconstruction of Monte Carlo, physical phantom, and patient data; the models were compared by quantifying total counts in hot regions of interest (ROIs) and activity contrast between hot ROIs and background regions. For typical matrix sizes in SPECT reconstruction, application of the 1D/rotation-based model provides a two-fold computational speed-up over the 2D model when running on GPU. Only small differences between the 1D/rotation-based and 2D models (order of 1%) were obtained for count and contrast quantification in select ROIs. A technique for CDR modeling in SPECT was proposed that (i) significantly speeds up reconstruction times, and (ii) yields nearly identical reconstructions to traditional 2D convolution based CDR techniques. The released toolbox will permit open-source development of similar models for different isotopes and collimators.

Nested compressive sensing for ECG signals using novel hybrid two-level approach of DWT and DCT sensing and sparsification

This paper demonstrates the merits of nested Compressive Sensing (CS) approach for Electrocardiogram (ECG) signals using discrete wavelet transform (DWT) and discrete cosine transform (DCT) as sensing matrix and sparsifying matrix. The implementation of CS framework is done using Gradient Projection for Sparse Reconstruction (GPSR). It is tested on 9 ECG signals of different arrhythmia categories obtained from MITBIH and BIDMC dataset. It is analysed for 3 different combinations, case (1) DCT sensing and DWT sparsification, case (2) DWT sensing and DCT sparsification and case (3) DWT sensing and DWT sparsification. A novel hybrid nested CS approach is proposed as case (4) which is a combination of case (2) in higher level and case (1) in lower level. This nested method yields the best PRD of 1.39 for CR = 0.2 and performs better than all proposed cases. This proposed approach involves a fair method of discarding the measurements in all frequency band and performs better than the state of the art work when the sampling rate is reduced by 4 times for ECG signal 100.dat from MIT-BIH (Massachusetts Institute of Technology-Beth Israel Hospital) database for CR = 0.2. It is shown that the reconstruction time of the proposed nested CS approach is lesser than non-nested CS approach.

Advances and Challenges of Single‐Pixel Imaging Based on Deep Learning

AbstractSingle‐pixel imaging technology can capture images at wavelengths outside the reach of conventional focal plane array detectors. However, the limited image quality and lengthy computational times for iterative reconstruction still hinder its practical application. Recently, single‐pixel imaging based on deep learning has attracted a lot of attention due to its exceptional reconstruction quality and fast reconstruction speed. In this review, an overview of the current status, and the latest advancements of deep learning technologies in the field of single‐pixel imaging are provided. Initially, the fundamental principles of single‐pixel imaging and deep learning, followed by a discussion of their integration and associated benefits are presented. Subsequently, a comprehensive review is conducted on the advancements of deep learning in various domains of single‐pixel imaging, covering super‐resolution single‐pixel imaging, single‐pixel imaging through scattering media, photon‐level single‐pixel imaging, optical encryption based on single‐pixel imaging, color single‐pixel imaging, and image‐free sensing. Finally, open challenges and potential solutions are discussed.

Comparison of 2 Different Types of Arterial and Biliary Anastomoses While Preserving the Gastroduodenal Artery: A Retrospective Study

ObjectiveHere we investigated 2 different arterial reconstruction procedures with preservation of the gastroduodenal artery (GDA) in orthotopic liver transplantation (OLT). MethodsA retrospective cohort study was conducted. The clinicopathological data of 40 pairs of donors and recipients who underwent OLT from May 2018 to August 2023 were analyzed. The GDA of all recipients was preserved during the hepatic arteries reconstruction, which were divided into 2 groups according to different anastomosis locations, namely the end-to-side group (E-S group, n = 17, Branch-patch between the common hepatic and the gastroduodenal artery) and end-to-end group (E-E group, n = 23, between common hepatic and proper hepatic). ResultsDemographics did not differ between both groups (P > .05). The warm ischemia time (WIT) was numerically longer in the E-S group (403.3 ± 103.3 vs 195.2 ± 35.8 s; P < .001), but the cold ischemia time (CIT) was numerically shorter in the E-S group (279.2 ± 74.7 vs 325.2 ± 15.1 min; P = .023). The time of artery reconstruction and duration of surgery was numerically shorter in the E-S group (21.0 ± 3.6 vs 51.0 ± 9.1 min, P < .001; 326.0 ± 103.4 vs 422.7 ± 24.6 min, P = .001). The E-S group had a lower resistance index (RI) (0.5 ± 0.3 vs 0.6 ± 0.1; P = .049). ConclusionBoth groups showed no differences in artery and biliary complications. GDA preservation meets the anatomical and physiological requirements. E-S is superior to E-E by the time of hepatic artery reconstruction and RI.

Management of Venoarterial Extracorporeal Membrane Oxygenation Cannulation-Associated Groin Wound Complications With Muscle Flaps at a High-Acuity Cardiac Referral Center.

The insertion of large bore cannulas into the femoral vessels for venous-arterial extracorporeal membrane oxygenation (VA-ECMO) administration has been associated with significant acute and chronic wound complications in patients with significant medical and surgical comorbidities, including vessel exposure and lymphocele development. In this series, we report our experience using muscle flap reconstruction in the management of post-ECMO groin wounds, with particular emphasis on groin lymphocele. VA-ECMO patients at a high-acuity cardiac referral center who developed groin cannulation site complications requiring muscle flap closure were included for retrospective review. Preoperative, perioperative, and postoperative factors were analyzed. Fifteen patients were included. The most common comorbidities were hypertension (66.7%), diabetes (46.7%), and renal failure (60.0%). Eight (53.3%) patients were immunosuppressed. The most frequent indications for surgery were groin lymphocele (n = 8, 53.3%) and exposed femoral vessels (n = 7, 46.7%). Median time from ECMO decannulation to reconstruction was 49.0 days. Most reconstructions were performed using a rectus femoris flap (n = 13, 86.7%). Two (13.3%) shallow wounds were covered with a sartorius muscle flap. Intraoperative cultures were positive in 9 (60.0%) patients. Seven (46.7%) patients experienced complications, including hematoma (n = 5), dehiscence (n = 1), recipient site infection (n = 1), and donor site infection (n = 1). In both groups, there were no cases involving lymphocele recurrence following reconstruction. There were no flap-specific complications and no cases of amputation. Four patients died within 1 year from septic shock (n = 3) and heart failure (n = 1). We report successful reconstruction in the majority of patients. In particular, muscle flap reconstruction is a useful technique for addressing ECMO-associated lymphocele development and recurrence. Future studies are needed to determine ideal timing of reconstruction and if early plastic surgeon involvement can reduce morbidity and mortality of these difficult to treat infections.

Bi-directional Projection Framework for Fast Single Image Super Resolution

Background:: Collaborative Representation (CR) has been widely used in Single Image Super Resolution (SISR) with the assumption that Low-resolution (LR) and high-resolution (HR) features can be linearly represented by neighborhoods and share consistent CR coefficients. Numerous patents and journal papers have been published. However, this CR consistency does not hold in the reconstruction phase, which leads to degraded performance. Methods:: To fulfill this gap, we propose a novel bi-directional projection model (BDPM) to establish a bi-directional mapping between LR and HR features without any consistency constraint. The multiple projection matrices are offline computed to reduce reconstruction time greatly. We further develop several strategies to extract features and group neighborhoods such that local structures can be preserved better. Results:: Compared to the learning-based methods, BDPM is about 2 to 10 times faster and compared to the reconstruction-based methods, it is about 500 to 2,000 times faster. Conclusion:: The empirical studies verify the effectiveness of BDPM and extensive experimental results demonstrate that BDPM achieves better SISR performance than many state-of-the-arts.

Dual-energy CT of acute bowel ischemia-influence on diagnostic accuracy and reader confidence.

This study evaluates the advantages in diagnostic accuracy, confidence, and reading time of additional dual-energy CT-derived reconstructions for assessing acute bowel ischemia. This retrospective study includes 25 patients with surgically proven acute bowel ischemia and 25 gender- and age-matched controls who underwent biphasic abdominal dual-energy CT. Two fellowship-trained abdominal radiologists and two residents evaluated all cases with and without additional dual-energy CT-derived iodine maps and virtual non-contrast images. Diagnostic confidence was rated on a 10-point Likert scale. Reading time was recorded. The inter-reader agreement was assessed using Fleiss' kappa. Sensitivity and specificity were compared using McNemar's test, reader confidence, and reading times with the Wilcoxon signed-rank test. For conventional images alone, the inter-reader agreement was moderate (κ = 0.58), with a sensitivity of 77% (95% CI: 67.5-84.8%) and specificity of 90% (95% CI: 82.4-95.1%). Adding dual-energy CT images, inter-reader agreement increased to substantial (κ = 0.69), sensitivity increased significantly to 89% (95% CI: 81.2-94.4%, p = 0.02), while specificity increased non-significantly to 93% (95% CI: 86.1-97.1%, p = 0.51). Diagnostic confidence increased significantly from 8 (IQR: 6-8) to 9 (IQR: 8-9) (p < 0.01). Equivalent diagnostic accuracy and confidence increases were observed for fellowship-trained and resident radiologists. A non-significant increase in mean reading time per case from 196 s to 201 s was observed (p = 0.30). Additional dual-energy CT reconstructions increase diagnostic accuracy and confidence without increasing reading time when evaluating suspected acute bowel ischemia. Both experienced and resident readers benefit from dual-energy CT images. Question There are too few clinical studies assessing the diagnostic accuracy of dual-energy CT (DECT) to recommend its use for evaluating suspected acute bowel ischemia. Findings Adding DECT-derived iodine maps and virtual-non-contrast images increase reader sensitivity and confidence while maintaining high specificity when evaluating for acute mesenteric ischemia. Clinical relevance Dual-energy CT should be used to investigate suspected acute bowel ischemia. Both diagnostic accuracy and confidence can be increased independent of reader experience without significantly increasing reading time.

Precision Denoising in Medical Imaging via Generative Adversarial Network-Aided Low-Noise Discriminator Technique

Medical imaging is significant for accurate diagnosis, and here, noise often degrades image quality, thus making it challenging to identify important information. Denoising is a component of traditional image pre-processing that helps prevent incorrect disease diagnosis. Mitigating the noise becomes difficult if there are differences in the low-level segment features. Therefore, a Generative Adversarial Network (GAN)-aided Low-Noise Discriminator (LND) is introduced to improve the denoising effectiveness in medical images with a balanced image resolution with noise mitigation. The LND function is a key that distinguishes between high- and low-noise areas based on segmented features, which are also achieved by tuning the peak signal-to-noise ratio (PSNR). Considering the training sequences, the LND-identified intervals lessen the sequences to improve the changes in pixel reconstruction. The generator function in this method is responsible for increasing the PSNR improvements over the different pixels cumulatively. The proposed method successfully improves the pixel reconstruction by 11.05% and PSNR by 9.75%, with 9.75% less reconstruction time and 13.11% less extraction error for the higher pixel distribution ratios than other contemporary methods.

Age and Surgical Volume Impact Likelihood and Technique of Lateral Extraarticular Augmentation During Primary Anterior Cruciate Ligament Reconstruction.

The aim of this study was to evaluate the current utilization trends of practicing surgeons performing and lateral extraarticular augmentation (LEA) at the time of primary anterior cruciate ligament reconstruction (ACLR). The survey was distributed via email in August 2023 to members of the Arthroscopy Association of North America (AANA) who identified as knee surgeons and was available online on the AANA website from January to September 2023. The eighteen-question survey was designed regarding surgeons' surgical utilization patterns of LEA during ACLR. Survey questions were created based on prior published research and recommendations regarding indications for LEA, as well as surgeon factors that have been shown to influence operative decision making. Data were analyzed by surgeon geographics, procedure preferences, patient-based decision factors, surgeon-based decision factors, and surgeon age. The survey was completed by 165 sports medicine surgeons who identified as arthroscopic knee surgeons. Majority practice types included private practice (42.1%), academic centers (26.8%), and hospital systems (20.7%). Surgeon age was 50.36 years (range 33-77). 6.8% perform < 20 ACLR per year, 30.2% perform 20-40, 26.5% perform 40-60, 10.5% perform 60-80, and 25.9% perform >80 per year. 79.4% of surgeons conduct LEA. The modified Lemaire being the most common technique (43.5%), followed by other lateral extraarticular tenodesis (LET) techniques (42.0%), and anterolateral ligament reconstruction (ALL) (27.5%), some surgeons (14.5%) use more than one technique. High volume (>60 ACLR/year) surgeons were more likely to perform LEA (23.1% vs 10.0%, p=0.061), and more likely to perform ALL (32.2% vs 16.5%, p=0.034). Younger surgeons (Age <50) were more likely to use the modified Lemaire (44.4% vs 24.3%, p=0.014). Decision-making to perform LEA weighted highly on patient hyperlaxity, pivot shift severity, knee hyperextension, sport-type, and age, respectively. The most reported surgeon-related factor influencing LEA utilization was training bias (38.9%). A large majority of orthopedic surgeons with diverse geographics, demographics, practice setting, and ACLR volume perform LEA. Younger surgeons performed more frequent LEA, and surgeons admit to training bias in decision making. Patient factors highly impacting utilization of LEA were hyperlaxity, pivot shift severity, knee hyperextension, sport, and age. LEA procedures for ACL reconstruction have become increasingly utilized in populations at high risk for re-rupture. However, there is not currently a clear standard of care with regards to LEA procedure type or indications for augmentation.

Photon-Counting Detector CT: Advances and Clinical Applications in Cardiovascular Imaging.

Since the approval of the first dual-source photon-counting detector CT (PCD-CT) in the fall of 2021, significant insights have been gained in its application for cardiovascular imaging. This review aims to provide a comprehensive overview of the current state of knowledge and the growing body of research literature, illustrating innovative applications and perspectives through case examples.We conducted a structured literature review, identifying relevant studies via Google Scholar and PubMed, using the keywords "photon-counting detector", "cardiovascular CT", "cardiac CT", and "ultra-high-resolution CT". We analyzed studies published since January 2015. Additionally, we integrated our own clinical experiences and case examples.In addition to the well-known benefit of increased temporal resolution offered by dual-source scanners, dual-source PCD-CT provides three key advantages: 1) Optimized geometric dose efficiency with an improved contrast-to-noise ratio, 2) intrinsic spectral sensitivity, and 3) the ability for ultrahigh-resolution CT. This technology enables improved image quality or radiation dose reduction in established cardiovascular protocols. Its use in non-invasive cardiac diagnostics for obese patients, those with a high plaque burden, or after stent implantation appears technically feasible, potentially expanding the scope of CT. The spectral sensitivity also allows tailored image acquisition, reducing metallic artifacts and contrast agent doses in patients with renal impairment. Early studies and clinical experience support these potential applications of PCD-CT in cardiovascular diagnostics, suggesting workflow optimization and improved patient management.However, challenges remain, including high costs, large data volumes, somewhat longer reconstruction times, and technical difficulties in combining spectral sensitivity with ultra-high resolution. Prospective randomized studies with clinical endpoints are lacking to confirm the clear advantage over conventional scanners. Future research should focus on endpoint-based studies and robust cost-benefit analyses to evaluate the potential of this technology and facilitate its evidence-based integration in clinical practice. · Photon-counting detector CT represents a technological advancement in computed tomography.. · Spectral sensitivity enhances iodine signal and minimizes artifacts.. · Ultra-high-resolution CT allows precise imaging, even in stents and advanced sclerosis.. · This technology must be validated through endpoint-based, randomized studies.. · Hagar MT, Schlett CL, Oechsner T et al. Photon-Counting Detector CT: Advances and Clinical Applications in Cardiovascular Imaging. Fortschr Röntgenstr 2024; DOI 10.1055/a-2452-0288.

Blip-up blip-down circular EPI (BUDA-cEPI) for distortion-free dMRI with rapid unrolled deep learning reconstruction

Purpose: BUDA-cEPI has been shown to achieve high-quality, high-resolution diffusion magnetic resonance imaging (dMRI) with fast acquisition time, particularly when used in conjunction with S-LORAKS reconstruction. However, this comes at a cost of more complex reconstruction that is computationally prohibitive. In this work we develop rapid reconstruction pipeline for BUDA-cEPI to pave the way for its deployment in routine clinical and neuroscientific applications. The proposed reconstruction includes the development of ML-based unrolled reconstruction as well as rapid ML-based B0 and eddy current estimations that are needed. The architecture of the unroll network was designed so that it can mimic S-LORAKS regularization well, with the addition of virtual coil channels.Methods: BUDA-cEPI RUN-UP – a model-based framework that incorporates off-resonance and eddy current effects was unrolled through an artificial neural network with only six gradient updates. The unrolled network alternates between data consistency (i.e., forward BUDA-cEPI and its adjoint) and regularization steps where U-Net plays a role as the regularizer. To handle the partial Fourier effect, the virtual coil concept was also introduced into the reconstruction to effectively take advantage of the smooth phase prior and trained to predict the ground-truth images obtained by BUDA-cEPI with S-LORAKS.Results: The introduction of the Virtual Coil concept into the unrolled network was shown to be key to achieving high-quality reconstruction for BUDA-cEPI. With the inclusion of an additional non-diffusion image (b-value = 0 s/mm2), a slight improvement was observed, with the normalized root mean square error further reduced by approximately 5 %. The reconstruction times for S-LORAKS and the proposed unrolled networks were approximately 225 and 3 s per slice, respectively.Conclusion: BUDA-cEPI RUN-UP was shown to reduce the reconstruction time by ∼88× when compared to the state-of-the-art technique, while preserving imaging details as demonstrated through DTI application.

Research on deep unfolding network reconstruction method based on scalable sampling of transient signals

In order to solve the problems of long reconstruction time and low reconstruction accuracy of compressed sensing reconstruction algorithm in the measurement of transient signals, a deep unfolding network reconstruction method based on scalable sampling is proposed to achieve fast and high-quality reconstruction of transient signal under low number of measurements. Firstly, the measurement process of compressed sensing is embedded into the neural network to realize automatic design and optimization of the observation matrix, which can reduce the number of measurements. Secondly, scalable sampling is introduced into the measurement process of compressed sensing, which can realize the training of data with different sampling ratios in the same model. Finally, a deep unfolding network model is designed to reconstruct the transient signal, which not only realizes the interpretability of the reconstructed network, but also achieves fast and high-quality reconstruction of the transient signal under the low number of measurements. Experimental results show that compared with the traditional compressed sensing reconstruction algorithms, the proposed method can obtain high-quality reconstruction accuracy with lower measurement times, and the reconstruction time is greatly reduced. The algorithm in this paper also obtains good reconstruction results under different sampling ratios, which shows that the method in this paper has good adaptability and effectiveness.

Ramp lesions of the medial meniscus are associated with greater preoperative anterior knee laxity in anterior cruciate ligament injury.

To assess the incidence of ramp lesions in anterior cruciate ligament (ACL) injuries and to compare preoperative knee laxity between the patients with and without ramp lesions by using an electromagnetic measurement system (EMS). Two hundred six patients who underwent primary ACL reconstruction with preoperative EMS measurements were retrospectively enrolled in the present study. The diagnoses of the ramp lesions were made by arthroscopic inspections. The patients with ramp lesions and no other meniscal lesions were allocated to 'ramp group', and the patients without any meniscal lesions were allocated to 'control group'. Before ACL reconstruction under general anaesthesia, the side-to-side difference (SSD) in anterior tibial translation (ATT) during Lachman test (mm) and tibial acceleration (m/s2) of posterior tibial reduction during the pivot-shift test was measured using the EMS. The SSD in tibial internal/external rotation angle (°) at 30, 60 and 90 were further measured using the EMS. The SSD in ATT using KT-2000 was also measured. Knee laxity measurements were compared between two groups using unpaired Student's t test. Ramp lesions were observed in 30 patients (14.7%). Subsequently, 17 patients were allocated to 'ramp group' and 77 patients to 'control group', and there were no statistical differences with regard to background demographics. ATT-SSD during Lachman test was significantly greater in 'ramp group' (9.1 [95% confidence interval, CI: 5.7-12.5] mm vs. 6.2 [95% CI: 5.1-7.3] mm, p = 0.037). However, SSD in ATT with KT-2000, tibial acceleration during pivot-shift test, and SSD in tibial rotational angles were not significantly different between the two groups. Presence of ramp lesion was associated with increased anterior knee laxity during Lachman test, suggesting ramp lesions may need to be addressed at the time of ACL reconstruction. IV.

Multi-objective optimization based robotic path planning for interpolation reconstruction model of CT data

Robotic path planning plays a pivotal role in computer-aided liver tumor thermal ablation surgery. However, traditional methods face challenges in terms of low reconstruction efficiency and planning safety. To address these issues, we propose a method for robotic path planning of liver tumor thermal ablation surgery. Firstly, an interlayer interpolation algorithm based on optical flow estimation is utilized to compensate for large interlayer spacing in computed tomography (CT) images by inserting predicted images between sequence images. Secondly, the voxel traversal strategy and patch intersection calculation strategy in the standard marching cube (MC) algorithm is optimized to improve the efficiency of abdominal tissues reconstruction. Finally, comprehensive clinical constraints are summarized to ensure the surgery safety and the strength pareto evolutionary algorithm II (SPEA-II) is leveraged to optimize surgery path, which can obtain even distribution of solutions in high-dimension optimization problems. Extensive experiments conducted on the 3Dircadb and SLIVER07 datasets revealed that our proposed method reduces reconstruction time by 21.5% compared to the standard MC algorithm, while achieving an average overlap rate of 88.25% and an average Hausdorff distance of 15.25 mm between Pareto front points and surgeon's recommended puncture points.

“Comparison of DIEP and PAP free flaps for breast reconstruction in the context of breast cancer: A retrospective study of 677 patients over 10 years”

BackgroundPAP (Profunda Artery Perforator) flap following cancer surgery has emerged as a relevant alternative for breast reconstruction but remains mainly used in cases where the DIEP (Deep Inferior Epigastric Perforator) flap cannot be performed. The aim of this work is to compare PAP and DIEP flaps’ surgical and aesthetics outcomes in breast reconstruction. MethodsWomen who underwent breast reconstruction by DIEP or PAP flap at the Plastic Surgery Department of Georges Pompidou European University Hospital, Paris, France, between January 2012 and December 2020 were included. Patient’s demographic characteristics were recorded as well as type, laterality and timing of reconstruction. Operative times, length of hospital stay, general and surgical complications were compared. The number of late surgical reoperations, their timing relative to the initial reconstructive procedure, and their purpose were also compared. ResultsA total of 677 patients were included, 559 of whom received a DIEP flap and 118 a PAP flap. PAP flap patients were significantly younger, thinner, and had a smaller initial bra cup size than those who received a DIEP (p<0.001) Operative time was similar for both groups (p=0.074). There was no difference in the number of early postoperative reoperations (p>0.554) or of late revisions (p>0.403) between DIEP or PAP. ConclusionProvided that the technical and human resources are available, PAP flap is a valid technique, with no increased risk of surgical complications and reoperations, nor lengthening of operative time. The PAP flap should be considered a primary therapeutic option and not only an alternative to the DIEP flap.

Surgical Predictors of Clinical Outcome 6 Years After Revision ACL Reconstruction

Background: Revision anterior cruciate ligament (ACL) reconstruction has been documented to have inferior outcomes compared with primary ACL reconstruction. The reasons why remain unknown. Purpose: To determine whether surgical factors performed at the time of revision ACL reconstruction can influence a patient’s outcome at 6-year follow-up. Study Design: Cohort study; Level of evidence, 2. Methods: Patients who underwent revision ACL reconstruction were identified and prospectively enrolled between 2006 and 2011. Data collected included baseline patient characteristics, surgical technique and pathology, and a series of validated patient-reported outcome instruments: Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) subjective form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Marx activity rating score. Patients were followed up for 6 years and asked to complete the identical set of outcome instruments. Regression analysis was used to control for baseline patient characteristics and surgical variables to assess the surgical risk factors for clinical outcomes 6 years after surgery. Results: A total of 1234 patients were enrolled (716 men, 58%; median age, 26 years), and 6-year follow-up was obtained on 79% of patients (980/1234). Using an interference screw for femoral fixation compared with a cross-pin resulted in significantly better outcomes in 6-year IKDC scores (odds ratio [OR], 2.2; 95% CI, 1.2-3.9; P = .008) and KOOS sports/recreation and quality of life subscale scores (OR range, 2.2-2.7; 95% CI, 1.2-4.8; P < .01). Use of an interference screw compared with a cross-pin resulted in a 2.6 times less likely chance of having a subsequent surgery within 6 years. Use of an interference screw for tibial fixation compared with any combination of tibial fixation techniques resulted in significantly improved scores for IKDC (OR, 1.96; 95% CI, 1.3-2.9; P = .001); KOOS pain, activities of daily living, and sports/recreation subscales (OR range, 1.5-1.6; 95% CI, 1.0-2.4; P < .05); and WOMAC pain and activities of daily living subscales (OR range, 1.5-1.8; 95% CI, 1.0-2.7; P < .05). Use of a transtibial surgical approach compared with an anteromedial portal approach resulted in significantly improved KOOS pain and quality of life subscale scores at 6 years (OR, 1.5; 95% CI, 1.02-2.2; P≤ .04). Conclusion: There are surgical variables at the time of ACL revision that can modify clinical outcomes at 6 years. Opting for a transtibial surgical approach and choosing an interference screw for femoral and tibial fixation improved patients’ odds of having a significantly better 6-year clinical outcome in this cohort.

Early Surgical Intervention Results in Better Patient-Reported Outcomes Than Delayed Treatment in Patients Undergoing Anterior Cruciate Ligament Reconstruction in the Presence of Concomitant Medial Collateral Ligament Injury

PurposeTo investigate the influence of the timing of ACL reconstruction (ACLR) on patient-reported outcomes, comparing those with and without concomitant medial collateral ligament (MCL) injury. MethodsThis study included patients who underwent ACLR between September 2015 and October 2020. Inclusion criteria required patients to have preoperative and postoperative patient-reported outcome measures (PROMs) and a follow-up period of at least 2 years. Patients who sustained a grade 2 or 3 MCL injury with an ACL tear were compared to patients with no MCL injury as a control. All patients underwent ACL reconstruction using either bone-tendon-bone (BTB) autograft or BTB Allograft. Patient-reported outcomes (International Knee Documentation Committee (IKDC), Lysholm, and Knee Osteoarthritis and Score (KOOS)) were recorded, and outcomes were analyzed by sex and time from index injury. A stratified linear mixed-effects regression analysis was conducted. ResultsA total of 253 eligible patients with 2-year outcomes were enrolled. Combined ACL/MCL injury had lower IKDC (β=-6.1 vs β=-8.3, p=0.003), KOOS QOL (β=-9.3 vs β=-11, p=0.004), and KOOS Sport (β=-12 vs β=-13 , p=0.08) if performed after 6 weeks from index injury. Isolated ACL injuries showed lower KOOS ADL (β=-2.4, p=0.045) if surgery performed between 3-6 months. For combined ACL/MCL injury, autograft (compared to allograft) was found to have worse IKDC (β=-11 (-18, -4.2), p=0.002), Lysholm (β=-9.2 (-15, -3.1), p=0.004), KOOS QOL(β=-11 (-20, -1.6), p=0.023), KOOS Pain (β=-5.1 (-10, -0.03), p=0.049), KOOS Symptoms (β=-7.6 (-10, -0.03), p=0.02), and KOOS Sports (β=-21 (-32, -10), p=<0.001). ConclusionPatients undergoing ACL reconstruction with a grade 2 or 3 MCL injury have improved patient-reported outcomes if surgery is performed within 6 weeks from the time of injury. In this cohort, allografts resulted in better outcome scores compared with autografts. Level of EvidenceLevel III Retrospective Cohort Study

Real-time ultrasound shear wave elastography using a local phase gradient

Background and Objective:Current approaches for ultrasound spectral elastography make use of block processing, resulting in long computational times. This work describes a real-time, robust, and quantitative imaging modality to map the elastic and viscoelastic properties of soft tissues using ultrasound. Methods:This elastographic technique relies on the spectral estimation of the shear-wave phase speed by combining a local phase-gradient method and angular filtering. We first apply directional filtering in the spatio-temporal frequency domain for providing one-way, smooth, and harmonic displacement maps in the frequency range of interest. Thanks to this, we can apply a simple, fast, and local phase gradient approach to obtain the axial and lateral components of the wavevector, which are linked to phase velocity and soft-tissue elasticity and viscoelasticity. The technique is validated numerically and experimentally using a 7.5 MHz ultrasound probe, tested in calibrated soft-tissue phantoms and ex vivo liver tissues. The method is compared with state-of-the-art spectral methods. Results:The technique significantly reduces the computation time, e.g., the reconstruction time for a 155 × 315-pixel phase-velocity map was 0.16 s, while local-phase velocity-imaging techniques was 156.73 s for 2D implementation and 13.56 s for the 1D version, a reduction between two and three orders of magnitude, while showing a similar accuracy and resolution than standard methods. Conclusions:This approach eliminates the need for block processing that may limit the spatial resolution and computational time of the velocity map. In this way, the phase gradient elastography method is revealed as an efficient and robust approach for real-time spectral elastography.

A sensing system and solving method for dynamic detection of relative pose of hydraulic support group

The precise detection of the pose of hydraulic support groups is crucial for the construction of intelligent coal mines. Addressing current challenges in comprehensive position sensing of support groups, such as one-sided descriptions, missing information, and limited detection capabilities, this paper, based on the concept of digital twin, proposes a sensing system and solving method for dynamic detection of the relative pose of hydraulic support group. Initially, a relative pose detection model, based on the six-point localization principle, is proposed by combining existing sensor information. Then, a sensing system is designed, incorporating a photoelectric detection device for monitoring key position parameters and virtual sensors for determining pose information. Consequently, a method for dynamically deriving relative positions, driven by the fusion of real-virtual iterative solving, real-virtual error feedback, and iterative condition optimization, is established. Finally, a relative pose dynamic detection system for a hydraulic support prototype is constructed in a laboratory environment. Experimental results demonstrate that the sensor system and the relative position detection method designed in this paper achieve a relative position accuracy of over 95.32 % for the hydraulic support, with a dynamic reconstruction time of less than 0.2 s. This verifies the rationality of the sensor system and the feasibility and accuracy of the dynamic deduction method. To sum up, this work provides a theoretical foundation and technical support for the autonomous perception of hydraulic support group, autonomous frame adjustment between frames, and overall straightness adjustment. It also lays the groundwork for further research and the advancement of information-physical systems in the fully-mechanized mining face.

Comparing Safety Profiles of Skin-Sparing and Nipple-Sparing Mastectomy With Deep Inferior Epigastric Perforator Flap Breast Reconstruction: A Retrospective Analysis.

Mastectomy is performed prior to or concurrently with deep inferior epigastric perforator (DIEP) flap breast reconstruction. However, the complication rates of nipple-sparing mastectomy (NSM) versus skin-sparing mastectomy (SSM) with DIEP are not well-characterized. This retrospective study included patients who underwent SSM or NSM with DIEP reconstruction between January 2019 and July 2022 at an academic institution. The primary outcome was 30-day postoperative complication rate. Variables were compared using Student's t-tests/Wilcoxon rank-sum and Chi-square/Fisher's exact tests. Of 535 patients, 195 (36%) underwent NSM and 340 (64%) underwent SSM. The 30-day postoperative complication rates did not differ between cohorts (16.4% in NSM vs. 16.8% in SSM, p > 0.9). The NSM cohort had a higher rate of any flap necrosis (9.2% vs. 3.5%, p = 0.01) compared to the SSM cohort, though rates of total DIEP flap loss rate did not differ (4.1% vs. 1.5% respectively). Site-wide total DIEP flap loss was 2.4%. The NSM cohort had smaller preoperative sternal notch-to-nipple distances (25.0 vs. 26.5 cm, p < 0.001) and had lower rates of preoperative radiation therapy (28.2% vs. 42.9%, p < 0.002) compared to the SSM cohort. The cohorts did not differ in demographic or operative variables including reconstruction timing (delayed vs. immediate interval), readmission, and reoperation. Individuals who received an NSM prior to DIEP reconstruction had more flap complications compared to the SSM cohort. Both cohorts had comparable overall 30-day postoperative complication rates and demographic variables, and rate of total DIEP flap loss was 2.4%. Patient preference can further guide surgical decision-making.