Joint Reconstruction Research Articles

A Multi-Hierarchical Complementary Feature Interaction Network for Accelerated Multi-Modal MR Imaging

Magnetic resonance (MR) imaging is widely used in the clinical field due to its non-invasiveness, but the long scanning time is still a bottleneck for its popularization. Using the complementary information between multi-modal imaging to accelerate imaging provides a novel and effective MR fast imaging solution. However, previous technologies mostly use simple fusion methods and fail to fully utilize their potential sharable knowledge. In this study, we introduced a novel multi-hierarchical complementary feature interaction network (MHCFIN) to realize joint reconstruction of multi-modal MR images with undersampled data and thus accelerate multi-modal imaging. Firstly, multiple attention mechanisms are integrated with a dual-branch encoder–decoder network to represent shared features and complementary features of different modalities. In the decoding stage, the multi-modal feature interaction module (MMFIM) acts as a bridge between the two branches, realizing complementary knowledge transfer between different modalities through cross-level fusion. The single-modal feature fusion module (SMFFM) carries out multi-scale feature representation and optimization of the single modality, preserving better anatomical details. Extensive experiments are conducted under different sampling patterns and acceleration factors. The results show that this proposed method achieves obvious improvement compared with existing state-of-the-art reconstruction methods in both visual quality and quantity.

Biological knee joint reconstruction using patella following giant cell tumor excision: a case report

A 20-year-old female patient presented to us with a large expansile swelling over right knee diagnosed clinically and confirmed histopathological and radiologically to be Giant Cell Tumor of upper end of Tibia involving both condyles with a breach in the posterior cortex. In this case report we tried to retain the joint function by biological reconstruction using the Patella after the wide excision of the tumor mass. A radical excision of the upper end of the Tibia was done. The Patella was used as an articular surface supported by ipsilateral Fibula and cortico-cancellous bone chips from the ipsilateral iliac crest as struts and complemented with synthetic bone graft pieces. Thus, the joint was reconstructed biologically. The case was followed for 1 year. The tumor was excised in toto, the knee joint was restored by the Patella and the bone graft struts. The results were discussed in detail.

Comparison of Decontamination-Preservation Protocols for Delayed Surgical Re-implantation of Osteoarticular Fracture Fragments

Background: To avoid discarding contaminated, devascularized osteoarticular fragments required for joint reconstruction, fragments need to be decontaminated while preserving chondrocyte viability. We hypothesized that disinfection with povidone-iodine or chlorhexidine followed by preservation using the Missouri Osteochondral Preservation System (MOPS) would allow for effective decontamination while retaining essential chondrocyte viability in osteoarticular fracture fragments for up to 14 days of shelf-stable point-of-care storage. Methods: With IACUC approval, purpose-bred hounds (n=16) were humanely euthanized for unrelated purposes and subjected to captive bolt trauma to create open distal humeral fractures. For each elbow (n=32), humerus, radius and ulna tissues were recovered such that 96 contaminated, devascularized osteoarticular fragments were randomly allocated to one treatment: Betadine (n=42): saline irrigation (1L), immersion in 10% povidone-iodine (20 min), saline irrigation; Chlorhexidine (n=42): saline irrigation, immersion in 0.002% chlorhexidine gluconate (20 min), saline irrigation; Injured Control (n=12): no decontamination treatment. After 7 or 14 days in MOPS, tissues were assessed by quantitative microbial culture and Viable Chondrocyte Density (VCD) measures. Results: Captive bolt trauma consistently resulted in type 3 open articular fractures. Injured Control osteoarticular fragments produced high polymicrobial counts at days 7 and 14. Chlorhexidine treatment was effective for decontaminating fragments such that no CFUs for clinically relevant bacteria were produced, while Betadine treatment was not fully effective at decontamination. Chlorhexidine decontamination followed by MOPS preservation maintained VCD in osteoarticular tissues over the desired 70% mean for 14 days, whereas the Injured Control group was associated with significant loss of VCD (Day-7=59%, Day-14=13%), which was further exacerbated by Betadine treatment (Day-7=29%, Day-14=6%). Conclusion: Contaminated, devascularized osteoarticular fracture fragments can be effectively decontaminated while maintaining essential chondrocyte viability for 14 days after type 3 open articular fractures using a decontamination-preservation protocol that combines saline irrigation with 0.002% chlorhexidine immersion followed by shelf-stable point-of-care storage in MOPS.

Disentangling the Faraday rotation sky

Context. Magnetic fields permeate the diffuse interstellar medium (ISM) of the Milky Way, and are essential to explain the dynamical evolution and current shape of the Galaxy. Magnetic fields reveal themselves via their influence on the surrounding matter, and as such are notoriously hard to measure independently of other tracers. Aims. In this work, we attempt to disentangle an all-sky map of the line-of-sight (LoS)-parallel component of the Galactic magnetic field from the Faraday effect, utilizing several tracers of the Galactic electron density, ne. Additionally, we aim to produce a Galactic electron dispersion measure map and quantify several tracers of the structure of the ionized medium of the Milky Way. Methods. The method developed to reach these aims is based on information field theory, a Bayesian inference framework for fields, which performs well when handling noisy and incomplete data and constraining high-dimensional-parameter spaces. We rely on compiled catalogs of extragalactic Faraday rotation measures and Galactic pulsar dispersion measures, a well as data on bremsstrahlung and the hydrogen α spectral line to trace the ionized medium of the Milky Way. Results. We present the first full sky map of the LoS-averaged Galactic magnetic field. Within this map, we find LoS-parallel and LoS-averaged magnetic field strengths of up to 4 µG, with an all-sky root mean square of 1.1 µG, which is consistent with previous local measurements and global magnetic field models. Additionally, we produce a detailed electron dispersion measure map that agrees with existing parametric models at high latitudes but suffers from systematic effects in the disk. Further analysis of our results with regard to the 3D structure of ne reveals that it follows a Kolmogorov-type turbulence for most of the sky. From the reconstructed dispersion measure and emission measure maps, we construct several tracers of variability in ne along the LoS. Conclusions. This work demonstrates the power of consistent joint statistical analysis including multiple datasets and physical quantities and defines a road map toward a full three-dimensional joint reconstruction of the Galactic magnetic field and the ionized ISM.

A preclinical model for osteoarticular fracture fragment preservation for delayed re-implantation

BackgroundOpen articular fractures often include contaminated, devascularized osteoarticular fragments that are critical for joint reconstruction. Definitive treatment is often delayed such that decontamination and preservation of critical fragments for joint reconstruction is highly desirable. To validate decontamination and preservation protocols for safe and effective preservation of osteoarticular fragments for re-implantation, a preclinical animal model for inducing type 3 open articular fractures with contaminated, devascularized osteoarticular fragments was developed and validated. Materials and methodsWith IACUC approval, purpose-bred hounds (n = 5) were humanely euthanized. Immediately following euthanasia, a penetrating captive bolt pistol with 1.25 grain cartridge centered on the cranial aspect of each distal humerus was discharged to create open fractures in 3 dogs (6 elbows). In 2 dogs, matched osteoarticular tissues from non-injured elbows (controls) were retrieved for comparison. Distal humerus, proximal radius, and proximal ulna osteoarticular fragments (n = 27) were immediately placed in Missouri Osteochondral Preservation System (MOPS) solution and stored at room temperature. Radiographic, chondrocyte viability, and quantitative microbial culture assessments were performed immediately (time-0) and at 7 and 14 days of storage. ResultsThis preclinical canine model reliably produced type 3 open distal humeral fractures characterized by devascularized and contaminated osteoarticular fracture fragments. All fragments produced extensive microbial growth through 14 days of storage. Without decontamination, viable chondrocyte density in the fragments decreased significantly within 7 days, likely attributable to the profound contamination. ConclusionThese data highlight the importance of developing a reliable method for point-of-care decontamination and preservation of osteoarticular fracture fragments for safe and effective reimplantation of articular fracture fragments for joint reconstruction.

Short-to-Mid-Term Outcomes of Ipsilateral Femoral Head Autograft Combined with Uncemented Total Hip Replacement for Partial Periacetabular Defects Following Tumor Resection.

Periacetabular tumors, especially in young to middle-aged patients with invasive benign tumors or low-grade malignant tumors involving type II or II + III, present significant challenges due to their rarity and the complexity of the anatomical and biomechanical structures involved. The primary difficulty lies in balancing the need to avoid unfavorable oncological outcomes while maintaining postoperative hip joint function during surgical resection. This study aimed to evaluate the effectiveness and reliability of a surgical method involving partial weight-bearing acetabular preservation combined with the use of an uncontaminated femoral head autograft to reconstruct the segmental bone defect after intra-articular resection of the tumorous joint, providing a solution that ensures both oncological safety and functional preservation of the hip joint in these patients. We conducted a retrospective study with a follow-up period of at least 36 months. From January 2010 to October 2020, we reviewed 20 cases of patients under 60 year of age with periacetabular invasive benign tumors or primary low-grade malignant tumors. All patients underwent reconstruction of the tumorous joint using autologous femoral head grafts. Data collected included patient age, gender, tumor type, preoperative and postoperative visual analog scale (VAS) scores, Musculoskeletal Tumor Society (MSTS) scores, Harris Hip Scores (HHS), patient survival rates, postoperative tumor recurrence, and surgical complications. To analyze the data, we utilized various statistical methods, including descriptive statistics to summarize patient demographics and clinical characteristics, and paired sample t-tests to compare preoperative and postoperative scores. The study included 20 patients, and a total median follow-up was 83 months. Their pathologic diagnoses comprised 13 giant cell tumors (GCTs), 5 chondrosarcomas, one chondroblastoma, and 1 leiomyosarcoma. Postoperatively, the median differences in vertical and horizontal center of rotation (COR) were 3.8 and 4.0 mm. Median limb length discrepancy (LLD) postoperatively was 5.7 mm (range, 2.3-17.8 mm). Two patients (10%) experienced delayed wound healing, resolved with antibiotics and early surgical debridement. One patient experienced dislocation 3 months postoperatively, which was promptly addressed under general anesthesia without further dislocation. Through multiplanar osteotomy with limited margins, femoral head autograft, and uncemented total hip replacement for pelvic segmental bone defects in selected patients in type II or II + III appears to be an encouraging limb-sparing surgery worthy of consideration for carefully selected patients.

Femoral and tibial phenotypes of varus alignment in a Southeast Asian arthritic population: a descriptive study.

Knowledge of femoral and tibial morphology is important for patient-specific surgery in both joint reconstruction and preservation procedures. Studies evaluating morphological variance in femoral and tibial alignments in Asian populations are scarce. This is the first descriptive study evaluating the femoral and tibial phenotypes of varus alignment in a Southeast Asian population. Long-leg coronal standing radiographs of 2021 limbs were obtained, and the hip-knee-ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle and joint line convergence angle were measured. Joint line obliquity was calculated, and the knees were classified according to the Coronal Plane Alignment of Knee (CPAK) classification. Descriptive analyses on alignment parameters and demographic data (age, gender, ethnicity and body mass index [BMI]) were performed and entered into a linear regression model. The highest frequency of limb alignment in the population was found to be CPAK type I (52.71%, n = 1003). Tibial varus was the largest contributor of varus malignment. Of the varus knees (n = 1247), varus deformity was found solely in the tibia (68.60%), solely in the femur (2.07%) and was contributed by both the femur and the tibia (4.97%). In the linear regression model, BMI was found to be a strong determinant for femoral varus (P = 0.004) and joint line incongruence (P < 0.001). The findings of this study will be important to surgeons during planning for joint preservation procedures (such as corrective osteotomies) and joint arthroplasties to restore alignment.

Predictors of Clinical Outcomes and Quality of Life After Sternoclavicular Joint Reconstruction With Hamstring Tendon Autograft

Background: Anterior instability of the sternoclavicular joint (SCJ) is a rare but potentially devastating pathological condition, particularly when it occurs in young or active patients. SCJ reconstruction using hamstring tendon autograft is a commonly used treatment option, yet to date results are limited to small case series. Studies on baseline, preoperative factors and their association with postoperative outcome are limited. Purpose: To assess the midterm clinical outcomes and survivorship after SCJ reconstruction using hamstring tendon autograft in patients experiencing anterior SCJ instability and to determine whether baseline patient or causative factors are associated with postoperative outcomes or patient satisfaction. Study Design: Case series; Level of evidence, 4. Methods: Patients who underwent SCJ reconstruction with a hamstring tendon autograft for anterior SCJ instability between October 2005 and October 2020 were included in this retrospective single-center study. At a minimum of 2 years postoperatively, clinical outcomes were collected, including the following patient-reported outcomes (PROs): the 12-Item Short Form Survey (SF-12) score; American Shoulder and Elbow Surgeons (ASES) score; Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score; Single Assessment Numeric Evaluation (SANE) score; and visual analog scale (VAS) pain score. Subjective postoperative satisfaction with the procedure was quantified on a scale from 0 (very unsatisfied) to 10 (very satisfied). The predictive role of patient factors, including age, sex, and injury in dominant arm, on postoperative PROs and satisfaction at short-term follow-up was evaluated using multiple linear regression. Results: A total of 49 patients (mean age, 29.6 ± 16.2 years; range 13.8-67.1 years; 27 females) were included in the final analysis. At a mean follow-up of 3.9 ± 2.1 years, all PROs had significantly improved, including the mean SF-12 Physical Component Summary score (40.4 ± 6.8 to 52.6 ± 6.9; P < .001), ASES score (54.9 ± 20.4 to 91.0 ± 11.3; P < .001), QuickDASH score (41.2 ± 18.5 to 10.2 ± 9.1; P < .001); SANE score (50.2 ± 21.1 to 88.3 ± 8.8; P < .001), VAS pain score (4.4 ± 2.6 to 0.8 ± 1.4; P < .001), and VAS pain score at its worst (7.4 ± 2.5 to 3.3 ± 2.6; P < .001). The median postoperative satisfaction score was 9 (range, 1-10). Revision-free survivorship was 95.9%. Male patients had a significantly lower VAS pain score at its worst compared with female patients (2.6 ± 2.6 vs 4.1 ± 2.4; P = .045); higher age was significantly correlated with a worse QuickDASH score (correlation coefficient, 0.314; P = .036). Overhead athletes had a significantly lower propensity to return to sport compared with nonoverhead athletes (P = .043), with only 45% of the overhead athletes returning to a level similar to their preinjury level, whereas 81% of the nonoverhead athletes were able to do so. Conclusion: The significant improvements in clinical and sport-specific outcomes and high patient satisfaction after SCJ reconstruction with a hamstring tendon autograft demonstrate the success of this procedure in treating anterior SCJ instability. Male sex and younger patient age are associated with superior outcomes, while overhead athletes have to be counseled about difficulties of returning to preinjury level of sport postoperatively.

Use of a Novel Reverse Hip Replacement System to Address Dislocation and Instability.

While total hip arthroplasty (THA) is an enormously successful treatment for patients with end-stage degenerative arthritis of the hip, and surgeons have optimized existing hip implants and techniques, dislocation and instability persist as a leading cause of failure. Given the tremendous success of reverse total shoulder arthroplasty in enhancing the stability of shoulder reconstruction by reversing the anatomic seating of the ball and socket components, one manufacturer (Hip Innovation Technology, LLC, Woodstock, Georgia) has developed a novel Reverse Hip Replacement System (Reverse HRS) to address the need for greater stability in reconstruction of the arthritic hip joint. Rather than the traditional anatomic components that replace the head of the femur with a spherical ball and the acetabulum with a socket with polyethylene liner mounted into the pelvis, the Reverse HRS features a cup with polyethylene liner attached to the femoral stem and a spherical metal head attached to a central trunnion inside of the porous-coated acetabular shell fixed into the pelvis. This design provides dramatically enhanced stability and improved range of motion. This article reviews relevant published literature, including results from a Canadian clinical trial and case reports from a multicenter American clinical trial monitored by the U.S. Food and Drug Administration. It also describes the components and surgical technique of reverse THA.

Space-time Fourier ptychography for in vivo quantitative phase imaging

Quantitative phase imaging of living biological specimens is challenging due to their continuous movement and complex behavior. Here, we introduce space-time Fourier ptychography (ST-FP), which combines a fast Fourier ptychography (FP) model based on compressive sensing with space-time motion priors for joint reconstruction of quantitative phase, intensity, and motion fields across consecutive frames. Using the same input data as compressive sensing FP, ST-FP increases the space-bandwidth-time product of the reconstructed complex image sequence while leveraging redundant temporal information to achieve robust reconstruction performance. The efficacy of this approach is demonstrated across various applications, particularly in observing living microorganisms undergoing rapid morphological changes and reconstructing amplitude and phase targets in motion. The improved phase retrieval capability of ST-FP enables digital refocusing, facilitating comprehensive three-dimensional analysis of microorganisms. This advancement paves the way for enhanced visualization of cellular processes, developmental biology studies, and investigations into life mechanics at the microscopic level.

The deltotrapezial fascia stabilizes the AC-Joint and its reconstruction restores the horizontal stability in AC-joint separations—a biomechanical comparison

BackgroundVarious techniques are available for the reconstruction of acromioclavicular joint (ACJ) dislocations, with the main focus being on restoration of the AC capsule or coracoclavicular (CC) ligaments. Recent research has underlined the significance of the deltotrapezial fascia (DTF) and related muscles as dynamic stabilizers of the ACJ. HypothesisReconstruction of the DTF increases the stability of the ACJ in the horizontal plane more than a complete transection of the fascia, while not restoring the stability of the native state. MethodsFive pairs of human cadaveric shoulders including the torsos were included in the study and underwent cyclic anterior-posterior loading using an electromechanical testing machine. The shoulders were put into three groups: group N (n = 10): native ACJ; group T (n = 10): ACJ with transected DTF; group R (n = 10): ACJ with reconstruction of the DTF after transection. The dislocation was recorded with an 3D optical measuring system. ResultsGroup N showed a mean horizontal displacement of 2.94 mm (± 1.26), group T showed a mean anterior displacement of 3.33 mm (± 1.37) and group R showed a mean anterior displacement of 2.95 mm (± 1.08). The mean anterior displacement for group T was significantly higher after every measured number of cycles compared with groups N and R. There was no significant difference in mean anterior displacement between groups N and R. ConclusionThe transection of the DTF results in significantly reduced stability in the horizontal plane of the ACJ. A reconstruction of the DTF restores the stability of the native ACJ in the horizontal plane. Further clinical and biomechanical investigations should focus on reconstruction techniques of the DTF.

Superior Suspensory Complex of the Shoulder Reconstruction for Acute and Chronic ACJ Dislocations: The QUASR 3-Tunnel Technique

BackgroundManagement of acromioclavicular joint (ACJ) injuries have wide variety of classification systems, surgical indications and operative techniques. Our study describes the QUASR (Queensland Unit for Advanced Shoulder Research) 3-Tunnel Technique with LARS (Ligament Augmentation and Reconstruction System; Surgical Implants and Devices, Arc sur Tille, France) artificial ligament to reconstruct the superior shoulder suspensory complex (SSSC) in acute, chronic and revision ACJ dislocations and lateral clavicle fractures. MethodsOur prospective cohort series of patients undergoing the QUASR 3-Tunnel Technique using LARS artificial ligament. This technique reconstructs the SSSC using two 4mm clavicle tunnels, one acromion tunnel, and is arthroscopically assisted to pass the artificial ligament under the coracoid. The ligament is secured with braided composite sutures and no interference screw is used. Pre and postoperative functional outcome scores were compared in patients with minimum 12-months follow-up. ResultsOf 26 patients in this series, 7 (27%) were operated within 4 weeks of injury, two (8%) were revision cases, and six (23%) were lateral clavicle fractures. Mean time to surgery was 14 weeks (2-650). Mean postoperative scores with associated 95% CI were Specific Acromioclavicular Score 87.38 (CI 75.38, 99.37), American Shoulder and Elbow Surgeons score 94.60 (87.85, 101.35), Constant 79.47 (71.87, 87.07), Simple Shoulder Test 85.44 (72.34, 98.54) and Visual Analogue Score 0.50 (-0.15, 1.15). There were two infections and one atraumatic loss of reduction, however there were no tunnel fractures. ConclusionThe QUASR 3-Tunnel Technique with LARS artificial ligament is a safe and efficient technique for both acute and chronic acromioclavicular joint reconstruction, lateral clavicle fractures with coracoclavicular ligament disruption and complex revision cases with favorable outcomes at mid-term follow-up.

Evaluation of grafts fixation techniques for temporomandibular joint reconstruction with medial femoral condyle flap: A numerical study

Reconstruction for large-scale temporomandibular joint (TMJ) defects can be challenging. Previously, we utilized the medial femoral condyle (MFC) flap for TMJ reconstruction. However, the optimal fixation method remains uncertain. In this study, finite element analysis was used to study the effects of three different fixation types of bone graft: overlap type, bevel type, and flush type. Models of different fixation types of MFC flap were reconstructed from CT images. A standard internal fixation model for extracapsular condylar fracture was also included as a control. Displacement of bone graft, deformation of plates and screws, and stress distribution of plates, screws, and cortical and cancellous of the bone graft were analyzed by finite element analysis to investigate their biomechanical features. The displacement of the bone graft and deformation of plates and screws in three different fixation types showed no significant difference. The overlap type and flush type of fixation displayed the lowest and highest stress respectively. All three fixation types could satisfy the mechanical requirement and face no risk of breakage and the major displacement of the MFC bone graft. These results provide insights into the optimal fixation approach for MFC bone grafts, offering valuable guidance and reference for clinical application.

Three-dimensional individual joint reconstruction through the Mako robotic arm-assisted surgical technique : Possibilities and limitations of the surgical technique

Although knee arthroplasty represents avery successful treatment for osteoarthritis or joint destruction, arelevant number of patients is still not completely satisfied with the outcome. Higher satisfaction and faster rehabilitation seem to be achievable through patient-individualized alignment of the prosthesis and especially through reproducible robotic-assisted implantation. The topic of robotics in orthopedics and especially in knee endoprosthesis is not new and began in the 1990s with the Robodoc system. The resurgence of robotics with new systems can be referred to as an innovation in the orthopedic operating room. Interest in this has risen significantly, not only among surgeons, but especially among patients, primarily because it seems to offer better joint function and patient satisfaction, as well as faster rehabilitation.

Prospects for joint reconstruction of imaging air Cherenkov telescope array and extensive air shower array

In this paper, we proposed a joint reconstruction of γ-ray events using both extensive air array (EAS) and Imaging air Cherenkov Telescope array (IACT). We considered eight Cherenkov telescopes to be built on the LHAASO (Large High Altitude Air Shower Observatory) site and investigate the improvement in differential sensitivity when combining the information from both IACT and Moun detectors of LHAASO-KM2A. We found that due to the higher cosmic ray background rejection power and higher gamma ray retention ratio provided by muon detectors of LHAASO, such a joint reconstruction can significantly improve the sensitivity of IACTs, especially for extended sources and long exposure time. The sensitivity of the eight-telescopes array can be improved by 25%−60% in different energy ranges using joint reconstructions with muon detectors.

Updates on temporomandibular joint reconstruction following ablative surgery.

Considerations regarding reconstruction of the temporomandibular junction (TMJ) following ablation have been underreported in head and neck surgery literature. Here, we discuss the complexity of reconstructing this unique joint and highlight the benefits and drawbacks of free tissue transfer. Additionally, we address the growing role of customized alloplastic implants and virtual surgical planning technologies in TMJ reconstruction. Technological advances in computerized manufacturing, 3D printing, and virtual reality have led to a recent burgeoning in patient-specific customization that may become the method of choice in these complex reconstruction cases. Since trauma and malignancy rarely compromise the entire TMJ, guidelines currently do not exist regarding how to best reconstruct the region in these unique cases. The methods that work in ankylosis and other intrinsic joint diseases are likely less appropriate in this patient population. Recent literature has reported improved patient outcomes and reduced operative times with virtual surgical planning techniques that may optimize autogenous graft approaches.

Joint diffusion: mutual consistency-driven diffusion model for PET-MRI co-reconstruction

Objective. Positron Emission Tomography and Magnetic Resonance Imaging (PET-MRI) systems can obtain functional and anatomical scans. But PET suffers from a low signal-to-noise ratio, while MRI are time-consuming. To address time-consuming, an effective strategy involves reducing k-space data collection, albeit at the cost of lowering image quality. This study aims to leverage the inherent complementarity within PET-MRI data to enhance the image quality of PET-MRI. Approach. A novel PET-MRI joint reconstruction model, termed MC-Diffusion, is proposed in the Bayesian framework. The joint reconstruction problem is transformed into a joint regularization problem, where data fidelity terms of PET and MRI are expressed independently. The regular term, the derivative of the logarithm of the joint probability distribution of PET and MRI, employs a joint score-based diffusion model for learning. The diffusion model involves the forward diffusion process and the reverse diffusion process. The forward diffusion process adds noise to transform a complex joint data distribution into a known joint prior distribution for PET and MRI simultaneously, resembling a denoiser. The reverse diffusion process removes noise using a denoiser to revert the joint prior distribution to the original joint data distribution, effectively utilizing joint probability distribution to describe the correlations of PET and MRI for improved quality of joint reconstruction. Main results. Qualitative and quantitative improvements are observed with the MC-Diffusion model. Comparative analysis against LPLS and Joint ISAT-net on the ADNI dataset demonstrates superior performance by exploiting complementary information between PET and MRI. The MC-Diffusion model effectively enhances the quality of PET and MRI images. Significance. This study employs the MC-Diffusion model to enhance the quality of PET-MRI images by integrating the fundamental principles of PET and MRI modalities and leveraging their inherent complementarity. Furthermore, utilizing the diffusion model to learn the joint probability distribution of PET and MRI, thereby elucidating their latent correlation, facilitates a more profound comprehension of the priors obtained through deep learning, contrasting with black-box prior or artificially constructed structural similarities.

Joint k-ω Space Image Reconstruction and Data Fitting for Chemical Exchange Saturation Transfer Magnetic Resonance Imaging.

Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is a novel MRI technology to image certain compounds at extremely low concentrations. Long acquisition time to measure signals at a set of offset frequencies of the Z-spectra and to repeat measurements to reduce noise pose significant challenges to its applications. This study explores correlations of CEST MR images along the spatial and Z-spectral dimensions to improve MR image quality and robustness of magnetization transfer ratio (MTR) asymmetry estimation via a joint k-ω reconstruction model. The model was formulated as an optimization problem with respect to MR images at all frequencies ω, while incorporating regularizations along the spatial and spectral dimensions. The solution was subject to a self-consistency condition that the Z-spectrum of each pixel follows a multi-peak data fitting model corresponding to different CEST pools. The optimization problem was solved using the alternating direction method of multipliers. The proposed joint reconstruction method was evaluated on a simulated CEST MRI phantom and semi-experimentally on choline and iopamidol phantoms with added Gaussian noise of various levels. Results demonstrated that the joint reconstruction method was more tolerable to noise and reduction in number of offset frequencies by improving signal-to-noise ratio (SNR) of the reconstructed images and reducing uncertainty in MTR asymmetry estimation. In the choline and iopamidol phantom cases with 10.5% noise in the measurement data, our method achieved an averaged SNR of 31.0 dB and 32.2 dB compared to the SNR of 24.7 dB and 24.4 dB in the conventional reconstruction approach. It reduced uncertainty of the MTR asymmetry estimation over all regions of interest by 54.4% and 43.7%, from 1.71 and 2.38 to 0.78 and 1.71, respectively.

Performing region-specific tasks does not improve lower extremity patient-reported outcome scores

BackgroundPatient-reported outcome measures quantify outcomes from patients’ perspective with validated instruments. QuickDASH (Quick Disability of Arm, Shoulder and Hand, an upper extremity PROM) scores improve after completing instrument tasks, suggesting patient-reported outcome results can be modified. We hypothesized that performing lower extremity tasks on the knee injury and osteoarthritis outcome score for joint reconstruction (KOOS-JR) and hip disability and osteoarthritis outcome score for joint reconstruction (HOOS-JR) instruments would similarly improve the scores.MethodsForty seven hip and 62 knee osteoarthritis patients presenting to a suburban academic center outpatient osteoarthritis and joint replacement clinic were enrolled and randomized to an intervention or a control group. Inclusion criteria were age over 18 years and English competency. Patients completed a HOOS-JR or KOOS-JR instrument, completed tasks similar to those of the instrument (intervention) or the QuickDASH (control), and then repeated instruments again. Paired and unpaired t-tests were used to compare the intervention and control group scores before and after tasks.ResultsThere was no significant difference in total or individual scores after task completion compared to baseline in either the HOOS-JR or the KOOS-JR groups. There was no significant difference in the scores between the intervention or control groups.ConclusionsDisability may be less modifiable in the lower extremity than in the upper extremity, perhaps because upper extremity activities are more easily compensated by the contralateral limb, or because lower extremity activities are more frequent. Thorough evaluation of factors influencing patient-reported outcome measures is necessary before their extensive application to quality control and reimbursement models.

Long-Term Follow-Up of Computer-Assisted Microvascular Mandibular Reconstruction: A Retrospective Study.

Background: Virtual surgical planning has become a well-established practice in head and neck surgery. In oncological surgery, it permits the achievement of safe margins resections and ensures functional reconstructions and optimal esthetic outcomes. This study aimed to evaluate the long-term outcomes after virtually planned mandibular microvascular reconstruction, focusing on functional and esthetic results, as well as health-related quality of life. Methods: A long-term retrospective evaluation of 17 patients with oral cavity malignancy who underwent computer-assisted mandibular resection and reconstruction was performed. Functional and esthetic outcomes were analyzed using the EORTC, QLQ-C30, H&N35, and FACE-Q questionnaires. Results: Time since reconstruction ranged from 7 to 14 years. Patients reported high functional levels on the QLQ-C30 functional scales but lower scores on H&N35. On FACE-Q, patients demonstrated higher appraisal and satisfaction with their smiles compared to their overall facial appearance. Conclusions: In this retrospective case series, patients undergoing computer-assisted mandibular reconstruction for oral malignancies achieved good long-term functional and esthetic outcomes. Although limited by the small sample size, these results support the enduring benefits of virtual planning for mandibular reconstruction. To minimize declines in function and appearance, considerations should include immediate dental implants, enhanced reconstruction of the temporomandibular joint, newer methods of radiotherapy to minimize xerostomia, and oral exercises to prevent trismus.