Orthogonal Images Research Articles

Transferring vision-based data to discontinuum analysis for the assessment of URM walls

This research presents a new workflow to assess unreinforced masonry (URM) walls based on vision-based data. The morphological features (i.e. brick pattern) of URM walls are obtained through high-resolution orthogonal images and then imported into a three-dimensional discrete element code (3DEC) to perform structural analysis via a semi-automatic procedure. URM walls are represented using rigid blocks that can mechanically interact along their boundaries. The mechanical interaction is simulated based on the point-contact hypothesis considering spring frictional elements. Once the numerical approach is validated using the results available in the literature, the proposed data-driven modelling strategy is applied to different URM wall cross-sections, with or without openings. The results show that the adopted semi-automatic workflow can be a fast and robust solution to simulate the structural behaviour of existing URM buildings by considering their construction techniques efficiently.

Return to Duty inMilitary Service Members Following Minimally Invasive Sacroiliac Joint Fusion.

As the utilization of minimally invasive sacroiliac joint fusion (SIJF) continues to expand, a better understanding of postoperative outcomes is needed, particularly in young and active individuals. The purpose of this study is to assess the outcomes of this procedure in an active duty military population by examining return-to-duty (RTD) rates. A retrospective review of the electronic medical record from a tertiary military medical center was performed for active duty service members undergoing SIJF from January 2013 to January 2019. The primary outcome measured was RTD at 6 months, with active duty status at 1 year, last follow-up, and revision surgery as secondary outcomes. Demographic and surgical variables recorded included patient age, gender, military rank, utilization of navigation, and implant type. Sixteen service members met the inclusion criteria, with a mean age of 40.5 ± 6.7 years. The mean follow-up after surgery was 24 ± 15 months. Patients received either cylindrical (n = 6) or triangular (n = 10) implants placed with (n = 6) or without (n = 10) navigation. Within 6 months of surgery, 56% of patients were able to RTD. Patients undergoing navigation-assisted procedures were significantly more likely to RTD at 6 months (100% vs. 30%, P = .011) compared to those undergoing surgery performed with orthogonal fluoroscopic imaging. Compared to those with cylindrical implants, patients with triangular implants were also more likely to RTD at 6 months (80% vs. 17%, P = .035). Following SIJF, a small majority of service members were able to return to full active duty status by 6 months. Further studies are needed to assess the potential benefits of navigation and implant selection, as our retrospective review noted differences in outcomes based on these variables.

Automatic area estimation of algal blooms in water bodies from UAV images using texture analysis

Algal blooms, the spread of algae on the surface of water bodies, have adverse effects not only on aquatic ecosystems but also on human life. The adverse effects of harmful algal blooms (HABs) necessitate a convenient solution for detection and monitoring. Unmanned aerial vehicles (UAVs) have recently emerged as a tool for algal bloom detection, efficiently providing on-demand images at high spatiotemporal resolutions. This study developed an image processing method for algal bloom area estimation from the aerial images (obtained from the internet) captured using UAVs. As a remote sensing method of HAB detection, analysis, and monitoring, a combination of histogram and texture analyses was used to efficiently estimate the area of HABs. Statistical features like entropy (using the Kullback–Leibler method) were emphasized with the aid of a gray-level co-occurrence matrix. The results showed that the orthogonal images demonstrated fewer errors, and the morphological filter best detected algal blooms in real time, with a precision of 80%. This study provided efficient image processing approaches using on-board UAVs for HAB monitoring.

Development of a prediction model for target positioning by using diaphragm waveforms extracted from CBCT projection images.

To develop a prediction model (PM) for target positioning using diaphragm waveforms extracted from CBCT projection images. Nineteen patients with lung cancer underwent orthogonal rotational kV x-ray imaging lasting 70 s. IR markers placed on their abdominal surfaces and an implanted gold marker located nearest to the tumor were considered as external surrogates and the target, respectively. Four different types of regression-based PM were trained using surrogate motions and target positions for the first 60 s, as follows: Scenario A: Based on the clinical scenario, 3D target positions extracted from projection images were used as they were (PMCL ). Scenario B: The short-arc 4D-CBCT waveform exhibiting eight target positions was obtained by averaging the target positions in Scenario A. The waveform was repeated for 60 s (W4D-CBCT ) by adapting to the respiratory phase of the external surrogate. W4D-CBCT was used as the target positions (PM4D-CBCT ). Scenario C: The Amsterdam Shroud (AS) signal, which depicted the diaphragm motion in the superior-inferior direction was extracted from the orthogonal projection images. The amplitude and phase of W4D-CBCT were corrected based on the AS signal. The AS-corrected W4D-CBCT was used as the target positions (PMAS-4D-CBCT ). Scenario D: The AS signal was extracted from single projection images. Other processes were the same as in Scenario C. The prediction errors were calculated for the remaining 10 s. The 3D prediction error within 3mm was 77.3% for PM4D-CBCT , which was 12.8% lower than that for PMCL . Using the diaphragm waveforms, the percentage of errors within 3mm improved by approximately 7% to 84.0%-85.3% for PMAS-4D-CBCT in Scenarios C and D, respectively. Statistically significant differences were observed between the prediction errors of PM4D-CBCT and PMAS-4D-CBCT . PMAS-4D-CBCT outperformed PM4D-CBCT , proving the efficacy of the AS signal-based correction. PMAS-4D-CBCT would make it possible to predict target positions from 4D-CBCT images without gold markers.

Comparison of setup accuracy of optical surface image versus orthogonal x-ray images for VMAT of the left breast using deep-inspiration breath-hold.

To compare the setup accuracy of optical surface image (OSI) versus orthogonal x-ray images (2DkV) using cone beam computed tomography (CBCT) as ground truth for radiotherapy of left breast cancer in deep-inspiration breath-hold (DIBH). Ten left breast DIBH patients treated with volumetric modulated arc therapy (VMAT) were studied retrospectively. OSI, 2DkV, and CBCT were acquired weekly at treatment setup. OSI, 2DkV, and CBCT were registered to planning CT or planning DRR based on a breast surface region of interest (ROI), bony anatomy (chestwall and sternum), and both bony anatomy and breast surface, respectively. These registrations provided couch shifts for each imaging system. The setup errors, or the difference in couch shifts between OSI and CBCT were compared to those between 2DkV and CBCT. A second OSI was acquired during last beam delivery to evaluate intrafraction motion. The median absolute setup errors were (0.21, 0.27, 0.23cm, 0.6°, 1.3°, 1.0°) for OSI, and (0.26, 0.24, 0.18cm, 0.9°, 1.0°, 0.6°) for 2DkV in vertical, longitudinal and lateral translations, and in rotation, roll and pitch, respectively. None of the setup errors was significantly different between OSI and 2DkV. For both systems, the systematic and random setup errors were ≤0.6cm and ≤1.5° in all directions. Nevertheless, larger setup errors were observed in some sessions in both systems. There was no correlation between OSI and CBCT whereas there was modest correlation between 2DkV and CBCT. The intrafraction motion in DIBH detected by OSI was small with median absolute translations <0.2cm, and rotations ≤0.4°. Though OSI showed comparable and small setup errors as 2DkV, it showed no correlation with CBCT. We concluded that to achieve accurate setup for both bony anatomy and breast surface, daily 2DkV can't be omitted following OSI for left breast patients treated with DIBH VMAT.

Dynamic intrafractional position monitoring with implanted fiducial markers for enhanced accuracy in radiotherapy of prostate cancer

Introduction: Recent advances in the radiation therapy of prostate cancer have brought a shift toward moderate- and ultra-hypofractionated treatment schedules. Reducing safety margins can broaden the therapeutic window in stereotactic treatments and alleviate concerns for toxicity in high dose-per-fraction treatment schedules. Management of intrafractional motion is a necessity for stereotactic body radiation therapy (SBRT). It can be achieved by performing intrafractional image guidance and position corrections. We evaluate the suitability of such a novel prostate motion management system and its potential benefit for treatment accuracy. Methods: Intrafractional IGRT was performed for 22 patients during 149 treatment sessions using repeated orthogonal kV-XR imaging of implanted fiducial markers with the ExacTrac Dynamic (EXTD) system. Position measurements were taken four times during each arc of the applied volumetric modulated arc therapy (VMAT). Position correction was performed if translational deviation exceeded 2 mm in any direction. Results: Of 677 single EXTD measurements, 20.6% exceeded the predefined threshold of 2 mm 3D deviation. Without intrafractional corrections, 39.4% of all individual measurements would exceed the threshold. The 3D accuracy could thus significantly be improved, reducing mean 3D shifts from 1.97 (± 1.44) mm to 1.39 (± 1.01) mm by performing intrafractional IGRT. In total, 34% of all treatment sessions required correction of intrafractional position shifts. Conclusion: Monitoring of prostate motion using repeated intrafractional orthogonal kV-X-ray-based position measurements of implanted fiducial markers proved to be a reliable method to improve precision of stereotactic irradiations of the prostate. It can prevent unacceptable translation deviations in one third of all sessions.

Broadband plasmonic metasurface for spin-selective hologram in near-infrared band

Metasurface holography is a significant technology for the development of ultrathin optical devices. Multichannel holography has received close attention due to its applications in increasing information capacity and optical secret sharing. However, existing design methods for multichannel holography mainly focus on interleaved metasurface imaging in the vertical direction, which will inevitably suffer from the unexpected crosstalk affecting imaging quality. This work presents noninterleaved spin-selective metasurfaces by combining the geometric phase and the propagating phase. It can achieve independent phase control on two orthogonal circular polarizations and image at the desired angle. As a proof-of-concept, two broadband plasmonic metasurfaces are designed for multichannel holographic imaging in the near-infrared band (800–1200 nm). When two orthogonal circularly polarized waves are normally incident, the first plasmonic metasurface displays two different holograms in the vertical direction, thus achieving dual-channel imaging, and the second plasmonic metasurface can make two holograms deflected to the desired angle. It means that these two holograms can be displayed without overlapping for a linearly polarized wave, and the orientable three-channel holographic imaging is realized. Our work provides a general and compact scheme for multichannel orientable holographic imaging.

Cyberknife treatment for different types of tumor

CyberKnife radiosurgery is a frameless, image guided robotic stereotactic radiosurgical system (IGR-SRS) which uses potent, ablative radiation dose with limited treatment volume. The main aim of this study is to provide knowledge of this treatment for different types of tumor. To deliver radiation treatment from multiple angles, with real time target tracking through a combined orthogonal radiograph imaging and optic motion tracking system cyberKnife is a new and advanced technique. Radiation is delivered to the tumor within a predetermined range, for this an object recognition computer algorithm and a fudicial marker placed within a tumor. CyberKnife treatment cost USD 6,800 (Indian Rupees approx. 4,89,000). In this review you will get idea about different types of tumor get treated with cyberKnife radiosurgery (SRS). CyberKnife have submillimeter accuracy in metastatic brain tumor. By giving appropriate tracking method for stage I lung cancer and lung oligometastases stereotactic radiotherapy is an efficient treatment. So, at well-defined tumor sites cyberKnife is a new stereotactic body radiation therapy which delivers high dose of radiation in short period of time. For head and neck tumor treatment cyberKnife is most widely used. This treatment is helpful for adrenal gland tumor and prostate tumor, spinal metastases.

SGReg: segmentation guided 3D/2D rigid registration for orthogonal X-ray and CT images in spine surgery navigation

Objective. One of the essential technologies in various image-guided spine surgeries is the rigid registration of 3D pre-operative CT and 2D intra-operative X-ray images. The 3D/2D registration is patterned as two essential tasks, that is, dimensional correspondence establishment and estimation of the 3D pose. 3D data is projected to 2D for dimensional correspondence by most of the existing methods, which makes pose parameters difficult to estimate caused by the loss of spatial information. This work aims to develop a reconstruction based 3D/2D registration method for spine surgery navigation. Approach. A novel segmentation-guided 3D/2D registration (SGReg) method for orthogonal X-ray and CT images was proposed based on reconstruction. SGReg consists of a bi-path segmentation network and an inter-path multi-scale pose estimation module. The X-ray segmentation path in the bi-path segmentation network reconstructs 3D spatial information from 2D orthogonal X-ray images to segmentation masks; meanwhile, the CT segmentation path predicts segmentation masks from 3D CT images, thereby bringing the 3D/2D data into dimensional correspondence. In the inter-path multi-scale pose estimation module, the features from the two segmentation paths are integrated, and the pose parameters are directly regressed under the guidance of the coordinate information. Main result. We evaluated SGReg using a public dataset CTSpine1k and compared the registration performance with other methods. SGReg achieved considerable improvement over other methods with great robustness. Significance We have proposed an end-to-end 3D/2D registration framework named SGReg. Based on the idea of reconstruction, SGReg performs a unified framework between dimensional correspondence establishment and direct pose estimation in 3D space, showing significant potential in spine surgery navigation.

Classification of female body shape based on two-dimensional image and computer vision technology

Traditional body classification methods are usually based on three-dimensional human body data. With the development of computer vision technology, two-dimensional (2D) anthropometry technology has garnered a great deal of research attention in the field of anthropometry. This paper presents a body shape classification and discrimination method using 2D images based on computer vision technology. The research included three main parts. (1) Index extraction of body shape classification based on computer vision. The orthogonal 2D human body image information of 362 young female samples was extracted. After normalizing the body height, three body shape classification indexes were separated: the body height pixel value ( H), the feature of the projected unit area ( ρ), and the feature of the projected area ratio of the front and side of the human body ( F). (2) Two-dimensional human body shape classification based on the two-step cluster model. The optimal classification number was determined, and the characteristics of each type of body shape were analyzed. (3) Automatic discrimination of the 2D human body shape based on the Bayesian algorithm. The correct rate of recognition was 94.8%. The results indicate that the body shape classification method based on computer vision technology and the selection of the proposed classification indexes are effective, and the accuracy of body shape recognition is high. In this paper, the classification of human body shape based on 2D digital images was realized, and this method can be applied to 2D anthropometry and other related fields.

Restoring microcirculatory perfusion in a preclinical model of severe hemorrhagic shock: The role of microcirculatory function.

No reflow in capillaries (no reflow) is the lack of tissue perfusion that occurs once central hemodynamics are restored. This prevents oxygen transfer and debt repayment to vital tissues after shock resuscitation. Since metabolic swelling of cells and tissues can cause no reflow, it is a target for study in shock. We hypothesize no reflow secondary to metabolic cell swelling causes the problem not addressed by current strategies that increase central hemodynamics alone. Anesthetized swine were bled until plasma lactate reached 7.5 mM to 9 mM. Intravenous low volume resuscitation solutions were administered (6.8 mL/kg over 5 minutes) consisting of; (1) lactated Ringer (LR), (2) autologous whole blood, (3) high-dose vitamin C (200 mg/kg), or (4) 10% PEG-20k, a polymer-based cell impermeant that corrects metabolic cell swelling. Outcomes were macrohemodynamics (MAP), plasma lactate, capillary flow in the gut and tongue mucosa using orthogonal polarization spectral imaging (OPSI), and survival to 4 hours. All PEG-20k resuscitated swine survived 240 minutes with MAP above 60 mm Hg compared with 50% and 0% of the whole blood and LR groups, respectively. The vitamin C group died at just over 2 hours with MAPs below 40 and high lactate. The LR swine only survived 30 minutes and died with low MAP and high lactate. Capillary flow positively correlated ( p < 0.05) with survival and MAP. Sublingual OPSI correlated with intestinal OPSI and OPSI was validated with a histological technique. Targeting micro-hemodynamics in resuscitation may be more important than macrohemodynamics. Fixing both is optimal. Sublingual OPSI is clinically achievable to assess micro-hemodynamic status. Targeting tissue cell swelling that occurs during ATP depletion in shock using optimized osmotically active cell impermeants in crystalloid low volume resuscitation solutions improves perfusion in shocked tissues, which leverages a primary mechanism of injury.

Tricuspid leaflet identification on 2D multiplane transoesophageal echocardiography: lessons from 3D

Abstract Funding Acknowledgements Type of funding sources: None. Background —Tricuspid valve (TV) leaflet identification by two-dimensional (2D) transoesophageal echocardiography (TOE) is complex due to the high variability of the combinations of leaflets visualized in each view. While three-dimensional (3D) imaging can easily overcome this problem by acquiring the whole valve anatomy, the overall image quality is often suboptimal and the technique somewhat unsuitable for real-time monitoring during interventional procedures like TriClip implantation. Using information derived from both 2D and multiplanar reconstruction (MPR) of 3D datasets, we aimed at describing anatomical landmarks able to identify TV leaflets easily and effectively during multiplane 2D TOE. Methods —TOE data from 83 patients was retrospectively collected. Multiplane 2D images of the TV and matching 3D datasets recorded from the same probe position were compared to precisely identify the leaflets visualized on each 2D image. To increase the number of multiplane (orthogonal) 2D images available for analysis, a novel approach was used: the 3D data of each patient was appropriately sliced to simulate and accurately match what would be seen by "sweeping" the cursor across the TV during real-time multiplane imaging (Fig. 1). After data analysis, a comprehensive "two-step" reference table was generated. To evaluate the clinical utility of the findings, eleven (11) echocardiographers were shown a random set of 5 images, and asked to label the leaflets visualized, prior and after a brief explanation on how to use the proposed reference table. Results —After removal of redundant information, a total of 231 sets of leaflets combinations was obtained. The number of leaflets visualized (one or two) and the presence (or absence) of the interventricular septum allowed consistent identification of the TV leaflets depicted in the 2D home view, as confirmed by correlation with the matching 3D MPR dataset. A similar analysis was carried out on the orthogonal 2D images resulting from three different multiplane cursor positions (distal, mid, and proximal to the aortic valve/interventricular septum). By combining information from the two views, leaflet identification was accurate, intuitive and easy, as summarized in the reference table (Fig. 2). The accuracy in exact leaflet recognition was rather modest (mean score of 1 out of 5) among echocardiographers with different experience in TV TOE, but significantly increased (mean score of 3.2 out of 5) with the adoption of the proposed approach, accounting for a 44% improvement in accuracy (p &amp;lt;0.001). Conclusion — Simple anatomical landmarks allow precise TV leaflet identification during multiplane 2D TOE. A simplified two-step approach significantly improves accuracy in leaflet recognition among both beginners and advanced echocardiographers.

An Orbitrap/Time-of-Flight Mass Spectrometer for Photofragment Ion Imaging and High-Resolution Mass Analysis of Native Macromolecular Assemblies.

We discuss the design, development, and evaluation of an Orbitrap/time-of-flight (TOF) mass spectrometry (MS)-based instrument with integrated UV photodissociation (UVPD) and time/mass-to-charge ratio (m/z)-resolved imaging for the comprehensive study of the higher-order molecular structure of macromolecular assemblies (MMAs). A bespoke TOF analyzer has been coupled to the higher-energy collisional dissociation cell of an ultrahigh mass range hybrid quadrupole-Orbitrap MS. A 193 nm excimer laser was employed to photofragment MMA ions. A combination of microchannel plates (MCPs)-Timepix (TPX) quad and MCPs-phosphor screen-TPX3CAM assemblies have been used as axial and orthogonal imaging detectors, respectively. The instrument can operate in four different modes, where the UVPD-generated fragment ions from the native MMA ions can be measured with high-mass resolution or imaged in a mass-resolved manner to reveal the relative positions of the UVPD fragments postdissociation. This information is intended to be utilized for retrieving higher-order molecular structural details that include the conformation, subunit stoichiometry, and molecular interactions as well as to understand the dissociation dynamics of the MMAs in the gas phase.

Machine learning algorithm inversion experiment and pollution analysis of water quality parameters in urban small and medium-sized rivers based on UAV multispectral data.

To examine and analyze the applicability of UAV multispectral images to urban river monitoring, this paper, taking the Fuyang River in the urban area of Handan Municipality as the object, the orthogonal image data of the river in different seasons were acquired by unmanned aerial vehicles (UAVs) equipped with multispectral sensors, and at the same time, the water samples were collected for physical and chemical indexes detection. Based on the image data, a total of 51 modeling spectral indexes were obtained by constructing three forms of band combinations ranging from the difference index (DI), ratio index (RI), and normalization index (NDI) and combining six single-band spectral values. Through the partial least squares (PLS), random forest (RF), and lasso prediction models, six fitting models of water quality parameters were constructed: turbidity (Turb), suspended, substance (SS), chemical oxygen demand (COD), ammonia nitrogen (NH4-N), total nitrogen (TN), and total phosphorus (TP). After verifying the results and evaluating the accuracy, the following conclusions were drawn: (1) The inversion accuracy of the three types of models is generally the same-summer is better than spring, and winter is the worst. (2) Water quality parameter inversion model based on two kinds of machine learning algorithms has more prominent advantages than PLS. RF model has good performance in the inversion accuracy and generalization ability of water quality parameters in different seasons. (3) The prediction accuracy and stability of the model are positively correlated to a certain extent with the size of the standard deviation of sample values. To sum up, by using the multispectral image data acquired by UAV and adopting the prediction models built upon machine learning algorithms, water quality parameters in different seasons can be predicted in different degrees.

Research on the muzzle vibration displacement test method of large-caliber rifled gun based trinocular vision

To address the problem of inaccurate muzzle vibration displacement measurements caused by the twisting of the barrel at the moment of firing of large-caliber rifled gun, a vibration displacement test method of large-caliber rifled gun based trinocular vision is proposed. A high-precision measurement system for muzzle vibration displacement based on an orthogonal imaging method with three high-speed cameras has been built. Three high-speed cameras are placed at the side and rear of the gun at orthogonal angles to each other to collect two-dimensional digital images of the gun muzzle area. Accurate displacement of the muzzle height, azimuth and recoil direction is derived by image processing techniques and multi-dimensional displacement decoupling methods. In addition, the three cameras can realize the online self-verification of parameters such as ‘recoil’ and ‘twist’. The three-dimensional vibration displacement and torsion parameters of the muzzle of a 155mm gun were obtained by a test of firing range. The test results proved the validity and accuracy of the method for the muzzle vibration displacement of rifled gun.

Multimodal microscopic imaging with deep learning for highly effective diagnosis of breast cancer

Accurate and rapid diagnosis of breast cancer is particularly important since it becomes the primary malignant tumor threatening women's health. Although pathological diagnosis with H&E staining section is the gold standard in tumor diagnosis, it is hard to meet quick intraoperative inspection because of its complex procedures and hysteresis. This study adopts multimodal microscopic imaging technology (bright-field imaging, auto-fluorescence imaging and orthogonal polarization imaging) combined with deep learning to achieve rapid intelligent diagnosis of breast cancer by getting the rich information of tissue morphology, content and structure of collagen in tissue slices. By using both fusion classification models of multimodal images at pixel level and decision level, the AUC score and accuracy is 0.9366 and 89.01% for the pixel fusion classification, as well as 0.9421 and 87.53% for the decision fusion classification, respectively. The results suggest that the multimodal microscopic imaging technique proposed in this study has unique advantages in accuracy, speed and feasibility in clinic for breast cancer diagnosis, and has strong clinical potential and application prospects when combined with deep learning.

Textile Physical Barriers: An Assessment of the Prison Effect as a Design Criterion to Increase the Porosity without Loss of Efficacy

Insect-proof screens are a physical method of crop protection against pests whose use is widespread. The hole size must be optimized since too small holes give rise to poorly porous textiles that cause a significant reduction in the permeability of the textiles to air. A common design strategy is to use a rectangular-hole geometry with the aim of limiting the hole width to prevent insect entry and increasing the hole length to increase the hole surface. However, the validity of this approach has not been tested, and indications suggest that it may not be offering the expected results. The results obtained discredit this widely accepted design criterion since they show that, while the hole width is maintained, protective screens lose efficacy as the hole length increases at least in the range of values considered. It is not possible to find an explanation for these results by considering the hole geometry from a two-dimensional point of view. However, when considering the spatial arrangement of the threads, it is understood that the passage surface for the insects is larger than that considered in the orthogonal projection images and that as the hole length increases, the efficacy of the textiles decreases.

Validation of a Novel Method of Measuring Cup Orientation Using BiPlanar Simultaneous Radiographic Images

BackgroundAccurate acetabular component positioning is paramount to the success of total hip arthroplasty (THA). Two-dimensional imaging alone remains a popular tool for implant position assessment despite known limitations. We investigated the accuracy of a novel method for assessing acetabular component position based upon orthogonal simultaneous biplanar X-ray images. MethodsThere were forty consecutive patients who had a preexisting THA on the contralateral side who underwent both computed tomography (CT) and simultaneous orthogonal biplanar radiographic scans for preoperative planning of THA. The operative inclination (OI) and operative anteversion (OA) of the acetabular cup were calculated by a new measurement method using the biplanar simultaneous scans. Those measurements were compared to measurement of the cup orientation on CT. The measurements were made by 2 independent observers. Interobserver correlation coefficients were calculated between the 2 observers to measure reliability. ResultsThe mean error in OA measurement of the acetabular cup between simultaneous orthogonal biplanar radiographic and CT imaging was 0.5° (SD: 1.9°, minimum −4.0°, maximum 5.0°), the mean error in OI was 0.0° (SD: 1.7°, minimum −5.0°, maximum 4.0°). The average absolute error was 1.5° for OA and 1.2° for OI. Interobserver correlation coefficient was 0.83 for OA and 0.93 for OI. ConclusionThe novel method of measuring cup orientation using simultaneous biplanar radiographic scans utilized in this study was accurate and reproducible between observers compared to CT measurements.

Multi-angled simultaneous biplane High-Speed Angiography (HSA) of patient-specific 3D-printed aneurysm phantoms using 1000 fps CdTe Photon-Counting Detectors (PCD's).

1000 fps HSA enables visualization of flow details, which may be important in accurately guiding interventional procedures; however, single-plane imaging may lack clear visualization of vessel geometry and flow detail. The previously presented high-speed orthogonal biplane imaging may overcome these limitations but may still result in foreshortening of vessel morphology. In certain morphologies, acquiring two non-orthogonal biplane projections at multiple angles can provide better flow detail rather than a standard orthogonal biplane acquisition. Flow studies of aneurysm models were performed, where simultaneous biplane acquisitions at various angles separating the two detector views allowed for better evaluation of morphology and flow. 3D-printed, patient-specific internal carotid artery aneurysm models were imaged with various non-orthogonal angles between the two high-speed photon-counting detectors (7.5 cm x 5 cm FOV) to provide frame-correlated simultaneous 1000-fps image sequences. Fluid dynamics were visualized in multi-angled planes of each model using automated injections of iodine contrast media. The resulting dual simultaneous frame-correlated 1000-fps acquisitions from multiple planes of each aneurysm model provided improved visualization of complex aneurysm geometries and flow streamlines. Multi-angled biplane acquisitions with frame correlation allows for further understanding of aneurysm morphology and flow details: additionally, the ability to recover fluid dynamics at depth enables accurate analysis of 3D flow streamlines, and it is expected that multiple-planar views will enable better volumetric flow visualization and quantification. Such better visualization has the potential to improve interventional procedures.

The effect of lifting load on the kinematic characteristics of lumbar spinous process in vivo

BackgroundThere are limited data on the in vivo natural kinematics of the lumbar spinous process. This paper intends to explore the effect of lifting load on the in vivo movement mode of the lumbar spinous process and its biomechanical changes.MethodsTen asymptomatic subjects between the ages of 25 and 39 underwent CT scans of the lumbar spine in the supine position, and 3D models of L3-L5 were constructed. Using a Dual Fluoroscopy Imaging System (DFIS), instantaneous orthogonal fluoroscopic images of each subject's flexion–extension, left–right bending, and left–right rotational movements were taken under different loads (0 kg, 5 kg, 10 kg). The supine CT model was matched, using computer software, to the bony contours of the images from the two orthogonal views, so that the instantaneous 3D vertebral position at each location could be quantified. A Cartesian coordinate system was ultimately constructed at the tip of the spinous process to obtain the 6DOF kinematic data of the spinous process.ResultsIn different postural movements of the trunk, there was no significant difference in the rotation angle and translation range of the lumbar spinous process under different loads (P > 0.05). In flexion to extension motion, spinous processes mainly rotate < 4° along the medial and lateral axes and translate < 4 mm along the craniocaudal direction. In the left–right bending motion, spinous processes mainly rotate < 5° along the anterior and posterior axes, and the translation is mainly coupling < 2 mm. In the rotational motion, the spinous process is mainly coupled motion, the rotation range is less than 3°, and the translation range is less than 2 mm. The distance between spinous processes measured in the supine position was 6.66 ± 2.29 mm at L3/4 and 5.08 ± 1.57 mm at L4/5.ConclusionThe in vivo kinematics of the lumbar spinous process will not change significantly with increasing low load. In complex motion, the spinous process is dominated by coupling motion.