A super-resolution algorithm to fuse orthogonal CT volumes using OrthoFusion.

OrthoFusion, an intuitive super-resolution algorithm, is presented in this study to enhance the spatial resolution of clinical CT volumes. The efficacy of OrthoFusion is evaluated, relative to high-resolution CT volumes (ground truth), by assessing image volume and derived bone morphological similarity, as well as its performance in specific applications in 2D-3D registration tasks. Results demonstrate that OrthoFusion significantly reduced segmentation time, while improving structural similarity of bone images and relative accuracy of derived bone model geometries.

Individuals with Heterogenous Trabecular Bone Texture by Clinical MRI have Lower Bone Strength and Stiffness by QCT Based Finite Element Analysis.

Opportunistic screening is essential to improve the identification of individuals with osteoporosis. Our group has utilized image texture features to assess bone quality using clinical MRIs. We have previously demonstrated that greater heterogeneity of MRI texture related to history of fragility fractures, lower bone density, and worse microarchitecture.

Diagnosis and evaluation of cervical ossification of the posterior longitudinal ligament on Zero-Echo Time Magnetic Resonance Imaging: an illustrative case series.

Purpose: Computed tomography (CT) scans are widely used clinically in the diagnosis of ossification of the posterior longitudinal ligament (OPLL). Conventionally acquired magnetic resonance imaging (MRI) is limited by insufficient signal intensity within bone tissue. Osseus conspicuity may be enhanced by applying sequences with "CT-like" bone contrast zero-echo time (ZTE) MRI.

Utility of Zero Echo Time MRI for the Diagnosis and Characterization of Ankle Fractures.

Zero echo time (ZTE) imaging is a relatively new magnetic resonance (MR) pulse sequence that provides bone-soft tissue contrast similar to that of computed tomography (CT). We sought to (1) determine the accuracy of ZTE MRI for the diagnosis of common ankle fractures and (2) investigate whether ZTE imaging sequences are equivalent to the gold standard of CT for the characterization of fracture fragments. We conducted a prospective case series of 54 patients with acute ankle trauma, in whom ZTE MRI was performed, followed by surgical reduction.

Baseline-to-loaded changes in regional tibial cartilage thickness, T1ρ and T2: Utilization of an MRI compatible loading device.

The objective of the study was to evaluate tibial cartilage thickness (TCT), T1ρ and T2 values within both loaded and baseline configurations in a cadaveric knee model using a 3D bone based tibial coordinate system. Ten intact cadaveric knees were mounted into an magnetic resonance imaging (MRI) compatible loading device. Morphologic and quantitative MRI (qMRI) images were acquired with the knee in a baseline configuration and after application of 50% body weight.

Fully automated determination of robotic pedicle screw accuracy and precision utilizing computer vision algorithms.

Historically, pedicle screw accuracy measurements have relied on CT and expert visual assessment of the position of pedicle screws relative to preoperative plans. Proper pedicle screw placement is necessary to avoid complications, cost and morbidity of revision procedures. The aim of this study was to determine accuracy and precision of pedicle screw insertion via a novel computer vision algorithm using preoperative and postoperative computed tomography (CT) scans.

OrthoFusion: A Super-Resolution Algorithm to Fuse Orthogonal CT Volumes.

OrthoFusion, an intuitive super-resolution algorithm, is presented in this study to enhance the spatial resolution of clinical CT volumes. The efficacy of OrthoFusion is evaluated, relative to high-resolution CT volumes (ground truth), by assessing image volume and derived bone morphological similarity, as well as its performance in specific applications in 2D-3D registration tasks. Results demonstrate that OrthoFusion significantly reduced segmentation time, while improving structural similarity of bone images and relative accuracy of derived bone model geometries.

Assessing carpal kinematics following scapholunate interosseous ligament injury ex vivo using four-dimensional dynamic computed tomography.

Background: Scapholunate interosseous ligament injuries are prevalent and often challenging to diagnose radiographically. Four-dimensional CT allows visualization of carpal bones during motion. We present a cadaveric model of sequential ligamentous sectionings ("injuries") to quantify their effects on interosseous proximities at the radioscaphoid joint and scapholunate interval.

Evaluation of Scapholunate Injury and Repair with Dynamic (4D) CT: A Preliminary Report of Two Cases.

 In predynamic or dynamic scapholunate (SL) instability, standard diagnostic imaging may not identify SL interosseous ligament (SLIL) injury, leading to delayed detection and intervention. This study describes the use of four-dimensional computed tomography (4DCT) in identifying early SLIL injury and following injured wrists to 1-year postoperatively.  4DCT acquires a series of three-dimensional volume data with high temporal resolution (66 ms).

Assessment of Patellar Vascularity after Patellar Cartilage Restoration via Lateral Parapatellar Approach: Analysis Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging.

Objective: Patellofemoral cartilage restoration procedures, including osteochondral allograft, particulated juvenile cartilage, and matrix-induced autologous chondrocyte implantation, have been shown to be effective treatments for patellofemoral cartilage lesions. However, concerns exist regarding disruption of the patellar vascular supply and secondary stabilizers of the patellofemoral joint during medial parapatellar approaches, especially when combined with a lateral release. A lateral parapatellar approach affords the possibility of avoiding disruption of the medial blood supply to the patella, while also allowing laterally-based soft tissue stabilization procedures.

Opportunistic Evaluation of Trabecular Bone Texture by MRI Reflects Bone Mineral Density and Microarchitecture.

Context: Many individuals at high risk for fracture are never evaluated for osteoporosis and subsequently do not receive necessary treatment. Utilization of magnetic resonance imaging (MRI) is burgeoning, providing an ideal opportunity to use MRI to identify individuals with skeletal deficits. We previously reported that MRI-based bone texture was more heterogeneous in postmenopausal women with a history of fracture compared to controls.

Optimizing Web-Based Viewer of 4D CT Scans for Clinical Assessment of Injured Wrists.

Wrist injuries pose a unique challenge for patients and providers. Due to the complexity of the wrist, it is difficult to determine if a wrist injury is primarily a bone fracture or soft tissue damage. The scapholunate interosseous ligament (SLIL) is an important ligament in the function of the wrist, and it is also one of the most common soft tissue injuries in the wrist.

The Dorsal Ligament Complex: A Cadaveric, Histology, and Imaging Study.

Purpose: The distinction between the dorsal intercarpal (DIC) and dorsal scaphotriquetral (DST) ligaments is imprecise and unclear in the literature. The purpose of our cadaveric study was to define the origins, insertions, and anatomic relationships of the dorsal wrist ligaments and relate these anatomic findings to magnetic resonance imaging (MRI) scans and histology.

Methods: The study included 17 unmatched fresh-frozen cadaveric specimens (7 male and 10 female), with a mean age of 67.

MRI-based Texture Analysis of Trabecular Bone for Opportunistic Screening of Skeletal Fragility.

Context: Many individuals at high risk for osteoporosis and fragility fracture are never screened by traditional methods. Opportunistic use of imaging obtained for other clinical purposes is required to foster identification of these patients.

Objective: The aim of this pilot study was to evaluate texture features as a measure of bone fragility, by comparing clinically acquired magnetic resonance imaging (MRI) scans from individuals with and without a history of fragility fracture.

Differences in the magnetic resonance imaging parameter T2* may be identified during the course of canine patellar tendon healing: a pilot study.

Background: Previous studies have utilized ultrashort echo (UTE) magnetic resonance imaging (MRI), and derived T2* maps, to evaluate structures with highly ordered collagen structures such as tendon. T2* maps may provide a noninvasive means to assess tendon damage and healing. This pilot study evaluated the longitudinal relationship of an induced mechanical strain on the patellar tendon with corresponding UTE T2* metrics, histologic and biomechanical evaluation at two post-operative time points.

Evaluation of Osseous Morphology of the Hip Using Zero Echo Time Magnetic Resonance Imaging.

Background: Femoroacetabular impingement syndrome (FAIS) is a common disorder of the hip resulting in groin pain and ultimately osteoarthritis. Radiologic assessment of FAI morphologies, which may present with overlapping radiologic features of hip dysplasia, often requires the use of computed tomography (CT) for evaluation of osseous abnormality, owing to the difficulty of direct visualization of cortical and subchondral bone with conventional magnetic resonance imaging (MRI). The use of a zero echo time (ZTE) MRI pulse sequence may obviate the need for CT by rendering bone directly from MRI.

Quantitative Magnetic Resonance Imaging and Histological Comparison of Normal Canine Menisci.

Objective:  The purpose of this observational study was to establish normative data for the canine menisci using magnetic resonance imaging (MRI).

Methods:  Ten fresh stifles from five normal male Beagles were obtained from animals with no known lameness. Conventional MRI and ultrashort echo time (UTE) imaging were performed and T* values calculated.

The SoftHand Pro: Functional evaluation of a novel, flexible, and robust myoelectric prosthesis.

Roughly one quarter of active upper limb prosthetic technology is rejected by the user, and user surveys have identified key areas requiring improvement: function, comfort, cost, durability, and appearance. Here we present the first systematic, clinical assessment of a novel prosthetic hand, the SoftHand Pro (SHP), in participants with transradial amputation and age-matched, limb-intact participants. The SHP is a robust and functional prosthetic hand that minimizes cost and weight using an underactuated design with a single motor.

The effect of glenohumeral plane of elevation on supraspinatus subacromial proximity.

Shoulder pain is a common clinical problem affecting most individuals in their lifetime. Despite the high prevalence of rotator cuff pathology in these individuals, the pathogenesis of rotator cuff disease remains unclear. Position and motion related mechanisms of rotator cuff disease are often proposed, but poorly understood.

Ideal Starting Point and Trajectory of a Screw for the Dorsal Approach to Scaphoid Fractures.

Purpose: To determine the screw starting point and trajectory for the dorsal approach to scaphoid fractures that provides a combination of length and compression at the fracture site.

Methods: Computed tomography scans were obtained of 10 scaphoid fractures for 3 common fracture types. A computerized model was generated for each scaphoid.

Grasp Performance of a Soft Synergy-Based Prosthetic Hand: A Pilot Study.

Current prosthetic hands are frequently rejected in part due to limited functionality and versatility. We assessed the feasibility of a novel prosthetic hand, the SoftHand Pro (SHP), whose design combines soft robotics and hand postural synergies. Able-bodied subjects ( ) tracked cursor motion by opening and closing the SHP and performed a grasp-lift-hold-release (GLHR) task with a sensorized cylindrical object of variable weight.