Volume-rendering Technique Research Articles

Complete sagittal suture closure evaluation based on post mortem computed tomography

Age assessment at the time of death is of great importance when an unidentified skeleton or corpse is found. Obliteration of cranial sutures has been used for age assessment regarding anthropology as non - metrical method of direct bone inspection. The aim of our study was to assess sagittal suture closure in the contemporary population of Polish men using postmortem computed tomography. A total of 255 male skulls were analyzed with the use of multiplanar reconstruction (MPR) and volume rendering technique (VRT) images, which were based on whole-body postmortem computed tomography scans. The individuals of Polish origin were of precisely known metrical age. The sagittal sutures were analyzed across their entire thickness (including both the outer and inner aspect of bone) and along their entire length via frontal sections, using the sagittal suture division into 4 segments. This study showed that the earliest signs of suture closure occur in S4 on the inner side of the calvaria at a mean age of 50.48years, but the youngest person with starting obliteration process was 13.37years. This is prove that exist variability which must be count during biological age estimation. Additionally, VRT visualisation shows that the fourth state of obliteration does not mean that obliteration was ended. Further analyses of cranial suture closure are needed to obtain reliable methods for postmortem estimation of the age at the time of death in contemporary populations. The use of postmortem computed tomography may offer additional opportunities for contemporary analysis of skeletal material.

3D Printed Models-A Useful Tool in Endovascular Treatment of Intracranial Aneurysms.

Many developments were made in the area of endovascular treatment of intracranial aneurysms, but this procedure also requires a good assessment of vascular anatomy prior to intervention. Seventy-six cases with brain aneurysms were selected and 1:1 scale 3D printed models were created. We asked three interventional neurosurgeons with different degrees of experience (ten years, four years, and a fourth-year resident) to review the cases using CTA (computed tomography angiogram) with MPR (multiplanar reconstructions) and VRT (volume rendering technique) and make a decision: coil embolization or stent-assisted coil embolization. After we provided them with the 3D printed models, they were asked to review their treatment plan. Statistical analysis was performed and the endovascular approach changed in 11.84% of cases for ten-year experienced neurosurgeons, 13.15% for four years experienced neurosurgeon, and 21.05% for residents. The interobserver agreement was very good between the ten years experienced interventionist and four years experienced interventionist when they analyzed the data set that included the 3D printed model. The agreement was higher between all physicians after they examined the printed model. 3D patient-specific printed models may be useful in choosing between two different endovascular techniques and also help the residents to better understand the vascular anatomy and the overall procedure.

Preoperative Determination of the Size of the Semitendinosus and Gracilis Tendon by Multidetector Row CT Scanner for Anterior Cruciate Ligament Reconstruction.

Accurately measuring the length and diameter of the hamstring tendon autograft preoperatively is important for planning anterior cruciate ligament (ACL) reconstructive surgery. The purpose of this study was to assess the reliability of three-dimensional computed tomography (3D CT) scanning technique to produce the actual measurement of the gracilis and semitendinosus (GT and ST, respectively) tendon grafts' length and diameter for surgery. Ninety patients were scheduled for ACL reconstruction with hamstring autograft. Before the surgery, patients were examined under the multidetector row CT scanner and the ST and GT tendons were qualitatively measured by a volume-rendering technique. The length of ST and GT was measured with 3D CT compared with the length of the harvested ST and GT. The cross-sectional area (CSA) of ST and GT measured with 3D CT compared with the ST and GT graft diameter. Tendon size measured preoperatively and during surgery were statistically compared and correlated. The GT tendons length and cross-sectional area measured during surgery was both shorter and smaller compared with the ST tendon. GT and ST tendon length were correlated to patients' body index such as the height and weight (p < 0.05). However, the correlation levels were low to medium (r = 0.23-0.49). There was strong correlation between the lengths of GT (r = 0.76; p < 0.001) and ST (r = 0.87; p < 0.001) measured with the 3D CT and tendon length at surgery. There was a moderate correlation between graft diameter measured at surgery and 3D CT cross-sectional area (r = 0.31; p < 0.05). A multidetector row CT scanner can determine the ST and GT tendons' length and diameter. These measurements can be used for preoperative planning to help determine the surgical method and counsel patients on appropriate graft choices prior to surgery.

Development and clinical evaluation of a contactless operating interface for three-dimensional image-guided navigation for endovascular neurosurgery.

PurposeIn endovascular neurosurgery, the operator often acquires three-dimensional (3D) images of the cerebral vessels. Although workstation reoperation is required in some situations during treatment, it leads to time loss because a sterile condition cannot be maintained and treatment must be temporarily interrupted. Therefore, a workstation reoperating system is required while maintaining the desired sterility.MethodsA contactless operating interface using Kinect to control 3D images was developed via gesture recognition for endovascular neurosurgery and was applied to a 3D volume rendering technique (VRT) image reconstructed at the workstation. The left-hand movement determines the assigned functions, whereas the right-hand movement is used like a computer mouse to pan and zoom in/out. In addition to the interface, voice commands were used and assigned to digital operations, such as image view changes and mode signal changes.ResultsThis system was used for the actual endovascular treatment of cerebral aneurysms and cerebral arteriovenous malformations. The operator and gesture were recognized without any problems. Using voice operation, it was possible to expeditiously set the VRT image back to the reference angle. Furthermore, it was possible to finely adjust gesture operations, including mouse operation, and treatment was completed while maintaining sterile conditions.ConclusionA contactless operating interface was developed by combining the existing workstation system with Kinect and voice recognition software, allowing surgeons to perform a series of operations, which are normally performed in a console room, while maintaining sterile conditions.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11548-021-02330-3.

Complex congenital heart defects and thoracic computed tomography in 3D stereoscopic relief: A qualitative assessment

Management of patients with complex congenital heart defects (CHD) requires 3D imagination skills for the spatial evaluation of cardiac structures. Current 3D imaging [echocardiography, MRI, computed tomography (CT)], projected on a 2D screen, limits the appreciation of the relief and the interaction of anatomical structures. The contribution of 3D stereoscopic relief imagery (3D S/R), built by triangle-based mesh generation, is more qualitative than quantitative, which is why its use, rarely reported in the literature, must be evaluated. 3D S/R was used from 2009 to 2019, as much as the CT made it possible to define a Region of Interest. Data and segmentation processing have been used to obtain four different types of reconstructions: MultiPlanar (MPR), Volume Rendering Technique (VRT), Surface Rendering Technique (SRT), and 3D S/R. The anaglyph 3D S/R effect requires the wearing of glasses (red - cyan blue filters) distributed during the session ( Fig. 1 ). Five complex CHD will be presented in MPR, VRT, then in SRT and 3D S/R: – Ventriculo-Arterial Malposition, – multiple Ventricular Septal Defects, – Anomalous Aortic Origin of a Coronary Artery, – Coarctation and hypoplastic Aortic Arch, – abnormal Pulmonary Arterial Arborization with Major Aorto-Pulmonary Collateral Arteries. The qualitative evaluation [MPR + VRT versus SRT and 3D S/R] will be carried out by questions/answers [Wooclap™ interactive system - voting on smartphone, in streaming, using a code associated with the presentation], allowing a global rating of the five CHD, concerning: – the perception of the relief, – the understanding of the cardiopathy, – the probability of appropriation of this 3D S/R imagery. This presentation will allow: – to assess the potential influence of 3D S/R on the management strategy of CHD, – to compare these imaging studies with mesh generation techniques leading to the more commonly reported 3D printing.

Volume Rendering Technique (VRT) for Planning and Learning Cranio-Vertebral Junction (CVJ) Surgeries: Technical Note.

To present the application of volume rendering technique (VRT) of computed tomography (CT) scan in cranio-vertebral junction (CVJ) surgeries. The authors used VRT images of CT scan in patients of congenital CVJ anomalies who were subjected to various surgeries through midline posterior approach. The screw entry points and courses of vertebral arteries were identified in relation to various landmarks on the VRT images, preoperatively and intra-operatively. A total of 15 patients of CVJ anomalies, who underwent surgeries through midline posterior approach, formed the study group. The screw entry points and courses of the vertebral arteries could be effectively identified in the surgical fields. We conclude that VRT images are an inexpensive and user friendly tool to identify the screw insertion points in the surgeries of CVJ anomalies. They also help in identifying the course of the vertebral artery in the surgical field. On the whole, their use makes the surgery in this region, safer.

Molecular Imaging of Chimeric Antigen Receptor T Cells By ICOS-Immunopet

Introduction: Immunomonitoring of chimeric antigen receptor (CAR) T cells relies primarily on their quantification in the peripheral blood, which inadequately quantifies their biodistribution and activation status in the tissues. Non-invasive molecular imaging of CAR T cell therapy by positron emission tomography (PET) is a promising approach providing spatial, temporal and functional information. Reported strategies for PET-based monitoring of CAR T cells rely on additional manipulation of the cell product such as the incorporation of reporter transgenes or ex vivo biolabeling, which significantly limits the wider application of CAR T cell molecular imaging. In the present study, we assessed the ability of antibody-based PET (immunoPET) to non-invasively visualize CAR T cells in vivo. Methods: For analysis of human CAR T cell activation, we analyzed publicly available RNA sequencing data (GSE136891) obtained at serial time points during in vitro culture of CD19.CD28z CAR T cells. We analyzed by mass cytometry (CyTOF) the ex vivo ICOS expression on human CD19-28z CAR T cells obtained from 31 patients receiving axicabtagene ciloleucel (Axi-cel) for relapsed/refractory diffuse large B-cell lymphoma (DLBCL). For in vivo murine experiments, CD19-expressing B-cell lymphoma A20 cells (2.5×10e5 cells) were injected by tail vein intravenously (i.v.) into sub-lethally (4.4 Gy) irradiated Thy1.2+ BALB/c mice. Seven days later, murine CD19.CD28z Luc+ Thy1.1+ CAR T cells (1×10e6) were i.v. injected. ICOS expression was analyzed by flow cytometry on CAR T cells recovered from spleen and bone marrow 5 days after injection. For imaging studies, anti-ICOS monoclonal antibody (mAb) specific for murine ICOS (clone:7E.17G9, BioXcell) was modified with the bifunctional chelator deferoxamine (DFO/p-SCN-Bn-Deferoxamine). The DFO-ICOS mAb conjugate was radiolabeled with 37 MBq (~1 mCi) of 89Zr-oxalate (final specific activity 6 µCi/µg/ml and radiochemical purity of 99%). 89Zr-DFO-ICOSmAb (45 μCi ± 3.6, 7.5 μg± 0.6) was injected i.v. 5 days post-CAR T cell administration and PET-CT imaging performed 48 hours later. Following PET-CT, mice were euthanized and radioactivity measured in dissected weighed tissues using a gamma-counter. Results: Analysis of RNA-sequencing data from human CAR T cells identified ICOS as an activation marker whose transcription was up-regulated and sustained during in vitro culture. ICOS was preferentially expressed on CAR+ T cells recovered at day 7 from axi-cel treated patients compared with CAR- cells (p&amp;lt;0.001; Figure 1A). Phenotypic analysis in a murine model of B cell lymphoma infiltrating the spleen and the bone marrow confirmed preferential ICOS expression on murine CAR T cells compared to resident cells in both spleen (p=0.003) and bone marrow (p=0.008). Figure 1B shows representative volume-rendered technique (VRT) PET/CT images of 89Zr-DFO-ICOS mAb-injected tumor-bearing mice either untreated (left panels) or that received mCD19.28z CAR T cells (right panels). 89Zr-DFO-ICOS mAb similarly accumulated in highly vascularized organs (heart, liver and spleen) of both untreated and CAR T cell treated mice, consistent with the biodistribution and clearance of intact antibodies. We detected pronounced 89Zr-DFO-ICOS mAb-PET signals in the bones of CAR T cell treated mice, particularly prominent in the lumbar spine, iliac bones, femur, tibia and humeral heads (Figure 1B). Region of interest analysis confirmed markedly increased radiotracer uptake in bones rich in bone marrow from CAR T treated mice compared with those of untreated mice (lumbar spine vertebrae p&amp;lt;0.001; iliac bones p=0.001; femur p=0.002; tibia p=0.002). Moreover we observed a slight, but statistically significant increase in radiotracer accumulation in the heart of CAR T cell-treated mice (p=0.004) while no significant differences were detected in spleen and liver. As expected, there was no significant signal difference in the muscle, considered background. Biodistribution analysis using gamma counting of tissues confirmed the PET results. Conclusions: We describe for the first time an immunoPET approach to monitor the in vivo dynamics of CAR T cell migration, expansion, and persistence that does not require the addition of reporter genes or ex vivo labeling, being therefore applicable to the clinical setting for the study of any commercially available and investigational CAR T cell products. Disclosures Miklos: Novartis: Consultancy, Other: Travel support, Research Funding; Allogene Therapeutics Inc.: Research Funding; Pharmacyclics: Consultancy, Other: Travel support, Patents &amp; Royalties, Research Funding; Juno-Celgene-Bristol-Myers Squibb: Consultancy, Other: Travel support, Research Funding; Janssen: Consultancy, Other: Travel support; Miltenyi Biotec: Research Funding; Kite-Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Adaptive Biotech: Consultancy, Other: Travel support, Research Funding. Mackall:BMS: Consultancy; Allogene: Current equity holder in publicly-traded company; Lyell Immunopharma: Consultancy, Current equity holder in private company; NeoImmune Tech: Consultancy; Nektar Therapeutics: Consultancy; Apricity Health: Consultancy, Current equity holder in private company. Gambhir:CellSight Inc: Current equity holder in private company. Negrin:Amgen: Consultancy; BioEclipse Therapeutics: Current equity holder in private company; Magenta Therapeutics: Consultancy, Current equity holder in publicly-traded company; Biosource: Current equity holder in private company; KUUR Therapeutics: Consultancy; UpToDate: Honoraria.

Colour-coded density-gradients stone mapping: A novel reporting system for stone density on non-contrast computed tomography and its clinical applications

ABSTRACT Objective To presents a novel clinically oriented system to report stone attenuation on non-contrast computed tomography (NCCT) using colour-coded density-gradients stone mapping and its clinical applications. Patients and methods This study was performed on 50 patients with 63 stones. All patients had a recent history of failed shockwave lithotripsy (SWL) or failed dissolution therapy by alkalinisation of urine for radiolucent stones. A multi-detector NCCT examination of the abdomen and pelvis was performed in all patients. The stones were isolated and displayed in ‘Volume Rendering Technique’ using four-colour encoding. Results Eight patients with failed dissolution therapy for radiolucent stones showed an outer layer of >500 Hounsfield units (HU) or a heterogeneous composition. A total of 42 patients with failed SWL had mean attenuations of <1000 HU on NCCT. Subsequent colour-coded stone mapping showed a dense core in all stones (>1000 HU) that failed to be clearly demonstrated by the mean HU alone. Conclusion The initial use of a colour-coded density-gradients stone mapping reporting system for stone density on NCCT is useful for explaining failure of SWL or failure of dissolution therapy for radiolucent stones in selected cases. Abbreviations: HU: Hounsfield units; MSD: mean stone density; NCCT: non-contrast computed tomography; PCNL: percutaneous nephrolithotomy; SWL: shockwave lithotripsy; VRT: Volume Rendering Technique

Diagnostic value and forensic relevance of a novel photorealistic 3D reconstruction technique in post-mortem CT.

Evaluation of performance and forensic relevance of a novel, photorealistic, 3D reconstruction method (cinematic rendering, (CR)) in comparison with conventional post-mortem CT (PMCT) and volume rendering (VR) technique for visualization of traumatic injuries. 112 pathologies (fractures, soft tissue injuries and foreign bodies) from 33 human cadavers undergoing whole body PMCT after traumatic death were retrospectively analyzed. Pathologies were reconstructed with CR and VR techniques. Fractures were classified according to their dislocation. Images were evaluated according to their expressiveness and judicial relevance by two forensic pathologists using a five-level Likert-scale (1: high expressiveness, 5: low expressiveness). They decided whether CR reconstructions were suitable for judicial reviews. The detection rate of pathologies was determined by two radiologists. CR was more expressive than VR for all three trauma categories (p < 0.01) and than conventional CT when used for fractures with dislocation (p < 0.001), injuries of the ventral body surface (p < 0.001), and demonstration of foreign bodies (p = 0.033). CR and VR became more expressive with a higher grade of fracture dislocation (p < 0.001). 20% of all pathologies in the CR and VR reconstructions were not detectable by radiologists. CR reconstructions are superior to VR regarding the expressiveness. For fractures with substantial dislocation, soft tissue injuries, and foreign bodies in situ, CR showed a significantly better expressiveness than conventional PMCT. CR and VR have significant limitations in cases of fractures with minor dislocations and covered soft tissue injuries. CR is a helpful tool to present pathologies found in PMCT for judicial reviews.

An Aberrant Line on CT Head: The Mendosal Suture.

A knowledge of variant anatomy is important in clinical practice. The skull bones have several normal anatomical variations, especially in the occipital bone. Accessory sutures have been described in newborns and young children.In this study, we discussed radiological findings of an accessory occipital suture in a 14-year-old child who had presented with mastoiditis and brain abscess. We further describe this “mendosal suture,” and its pathophysiology and clinical implications. It is important to bear this entity in mind to avoid misdiagnosing this as a fracture. The use of CT scans and 3D CT using volume rendering technique (VRT) helps in detection and correct diagnosis.

An Overview of Volume Rendering Techniques for Medical Imaging

One of the most valuable medical imaging visualizations or computer-aided diagnosis is Volume rendering (VR). This survey’s objective is reviewing and comparing between several methods and techniques of VR, for a better and more comprehensive reading and learning of both pros and cons of each method, and their use cases.

Intralobar Pulmonary Sequestration with 3 Aberrant Arteries in a 2-Year-Old Boy

Pulmonary sequestration is a rare congenital pulmonary malformation. This malformation consists of dysplastic lung tissue with no connection to the tracheobronchial tree and with an anomalous systemic arterial supply. The clinical hallmarks of intralobar sequestration are recurrent pulmonary infections. Chest CT scan with contrast is actually gold standard for identifying pulmonary sequestration. CT volume-rendering technique image reconstructions can be particularly helpful in detecting anomalous arterial vessels and show the venous drainage. Surgical resection is the treatment of choice and intralobar sequestration often requires lobectomy. We present an interesting case of intralobar pulmonary sequestration with 3 aberrant arteries arising from the descending thoracic aorta in a 2-year-old boy.

Cross-anatomical, radiographic and computed tomographic study of the stifle joint of donkeys (Equus africanus asinus).

The present investigation was conducted to provide a full anatomical description of the stifle joint of donkeys using 3D computed tomography imaging technique, in addition to the classic anatomical methods, such as radiography and cross-anatomical sectioning. The radiography and CT imaging of stifle joint were interpreted in comparison with cross-sectional anatomical sections. Volume-rendering reconstruction techniques (3D-CT) were used to describe the anatomical structure of stifle joint. The used twelve adult healthy donkeys were free from any musculoskeletal disorders. Four donkeys were used for the gross anatomical observations, four for CT and radiography and two live animals for determination the site of injections. The results of this study revealed that the complex stifle joint was formed from three joints: femorotibial, femoropatellar and proximal tibiofibular. The articular surfaces were described for each joint, and the synovial layer of the articular capsule formed three main joint sacs: femoropatellar, medial femorotibial and lateral femorotibial sacs. The ligaments of stifle joint were recorded, and meniscal ligaments included cranial and caudal ligaments of medial and lateral menisci and meniscofemoral ligament of lateral meniscus. The cruciate ligaments were also described and they included the cranial and caudal cruciate ligaments, while the patellar ligament included the medial, middle and lateral patellar ligaments. The arterial supply and the site of injection of the stifle joint were described. In conclusion, the 3D reconstruction CT provided well-defined baseline reference image for the stifle joint of donkeys for anatomist, radiologist, surgeons and researchers.

Severe COVID-19 Pneumonia: Assessing Inflammation Burden with Volume-rendered Chest CT.

HomeRadiology: Cardiothoracic ImagingVol. 2, No. 2 PreviousNext Images in Cardiothoracic ImagingFree AccessPulmonary ImagingSevere COVID-19 Pneumonia: Assessing Inflammation Burden with Volume-rendered Chest CTLei Tang, Xiaoyong Zhang, Yvquan Wang, Xianchun Zeng Lei Tang, Xiaoyong Zhang, Yvquan Wang, Xianchun Zeng Author AffiliationsFrom the Department of Radiology, Guizhou Provincial People’s Hospital, Guiyang 550002, Guizhou Province, China.Address correspondence to X. Zeng (e-mail: [email protected]).Lei TangXiaoyong ZhangYvquan WangXianchun Zeng Published Online:Mar 6 2020https://doi.org/10.1148/ryct.2020200044MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In COVID-19 (formerly known as 2019 novel coronavirus [2019-nCoV]) broke out in December 2019, and it spread from Wuhan, Hubei Province, to all over China and many other countries in the world (1–4). A 54-year-old woman with a travel history to Wuhan was admitted to the hospital with a 7-day history of fever (38.5°C [101.3°F]), cough, fatigue, and chest congestion. Laboratory examinations showed normal white blood cell count and lymphocytopenia, increased C-reactive protein level and erythrocyte sedimentation rate, and decreased CD3+, CD4+, CD8+, and CD4/CD8. Unenhanced chest CT revealed patchy peripheral ground-glass opacities with upper lobe predominance (Fig 1). A three-dimensional volume-rendering technique (PULMO 3D software, VB20; Siemens Healthineers, Forchheim, Germany) highlighted the distribution of pulmonary opacities, which was useful to determine the extension of the disease (Fig 2, Movie [supplement]). Her nasopharyngeal swab was positive for COVID-19 with real-time fluorescence polymerase chain reaction test. The patient was diagnosed with severe COVID-19 pneumonia. When treated with oxygen inhalation, moxifloxacin, lopinavir/ritonavir, umifenovir, interferon, and thymosin, her body temperature returned to normal and the symptoms slightly improved. CT reexamination on the 5th day of hospitalization indicated increased lesions and mild absorption on the 9th day.Figure 1: CT images in a 54-year-old woman with severe COVID-19 pneumonia. Transverse and coronal images reveal patchy peripheral ground-glass opacities with upper lobe predominance.Figure 1:Download as PowerPointOpen in Image Viewer Figure 2: CT images in a 54-year-old woman with severe COVID-19 pneumonia. A, The color coronal image highlights the distribution of lung lesions (red areas) because software is used to automatically segment and render. B, On a three-dimensional volume-rendering image, trachea, bronchus, lung tissues, and lesions are differentiated by CT values and automatically segmented.Figure 2:Download as PowerPointOpen in Image Viewer Get the Flash Player to see this video.Movie Three-dimensional volume-rendering movie in a 54-year-old woman with severe COVID-19 pneumonia. The images highlight the distribution of pulmonary lesions, which are useful to determine the extension of the inflammatory burden.Download Original Video (3.4 MB)Disclosures of Conflicts of Interest: L.T. disclosed no relevant relationships. X. Zhang disclosed no relevant relationships. Y.W. disclosed no relevant relationships. X. Zeng disclosed no relevant relationships.Keywords: CT, Computer Applications-3D, Infection, Lung Authors declared no funding for this work.

Is CT-based cinematic rendering superior to volume rendering technique in the preoperative evaluation of multifragmentary intraarticular lower extremity fractures?

PurposeCinematic rendering (CR), a recently launched, FDA-approved rendering technique converts CT image datasets into nearly photorealistic 3D reconstructions by using a unique lighting model. The purpose of this study was to compare CR to volume rendering technique (VRT) images in the preoperative visualization of multifragmentary intraarticular lower extremity fractures. MethodIn this retrospective study, CT datasets of 41 consecutive patients (female: n = 13; male: n = 28; mean age: 52.3 ± 17.9y) with multifragmentary intraarticular lower extremity fractures (calcaneus: n = 16; tibial pilon: n = 19; acetabulum: n = 6) were included. All datasets were acquired using a 128-row dual-source CT. A dedicated workstation was used to reconstruct CR and VRT images which were reviewed independently by two experienced board-certified traumatologists trained in special trauma surgery. Image quality, anatomical accuracy and fracture visualization were assessed on a 6-point-Likert-scale (1 = non-diagnostic; 6=excellent). The regular CT image reconstructions served as reverence standard. For each score, median values between both readers were calculated. Scores of both reconstruction methods were compared using a Wilcoxon-Ranksum test with p < 0.05 indicating statistical significance. Inter-reader agreement was calculated using Spearman’s rank correlation coefficient. ResultsCompared to VRT, CR demonstrated a higher image quality (VRT:2.5; CR:6.0; p < 0.001), a higher anatomical accuracy (VRT:3.5; CR:5.5; p < 0.001) and provided a more detailed visualization of the fracture (VRT:2.5; CR:6.0; p < 0.001). An additional benefit of CR reconstructions compared to VRT reconstructions was reported by both readers in 65.9 % (27/41) of all patients. ConclusionsCR reconstructions are superior to VRT due to higher image quality and higher anatomical accuracy. Traumatologists find CR reconstructions to improve visualization of lower extremity fractures which should thus be used for fracture demonstration during interdisciplinary conferences.

Quantification of macropores of Malan loess and the hydraulic significance on slope stability by X-ray computed tomography

The accurate identification and quantitative characterization of loess structural properties at the pore scale are important in the study of macroscopic permeability. To characterise the macropore structure of Malan loess systematically, a non-destructive detecting method, that is, X-ray computed tomography (CT), was adopted for scanning five undisturbed specimens. A series of processing steps, including image filtering by a novel compositing image filter, image segmentation with the effective combination of threshold and top hat method, and three-dimensional (3D) reconstruction and visualisation by marching cube algorithm and volume-rendering technique were finished in AVIZO® software to acquire the 3D pore network model and to extract the two-dimensional (2D) and 3D structural parameters, such as porosity, equal diameter, aspect ratio, shape factor (SF), node density, number of terminal and branching nodes, coordinate number, dip angle, dip direction angle and tortuosity. Results show that (1) Malan loess is a kind of porous geological material with strong verticality and spatial anisotropy reflected by the 2D parameters including porosity, equal diameters and aspect ratio as well as the 3D dip angle and 3D-visualised loess macropores; (2) Malan loess has higher permeability in the vertical direction than that in the horizontal direction so that prone to induce excessive infiltration and preferential flow, thereby threatening the loess slope stability; (3) SF is an effective parameter for pore classification in both 2D and 3D scales; (4) the macropores with a large diameter have a larger volume fraction, better connectivity (effective porosity) and greater contribution to water permeability; (5) the larger the coordinate number, the greater the hydraulic conductivity, nevertheless other than the aggregates for the water repellency caused by organic matter. In conclusion, the combination of CT and AVIZO® is excellent for quantifying the key macropore structural parameters (e.g., shape factor and tortuosity) and their hydraulic significance on slope stability.

How to Size Intracranial Aneurysms: A Phantom Study of Invasive and Noninvasive Methods.

Endovascular treatment of intracranial aneurysms has relevantly changed over the past decades. Multiple new devices such as intrasaccular flow diverters have broadened the treatment spectrum but require very exact aneurysm sizing. In this study, we investigated multidetector and flat panel angiographic CT and digital subtraction imaging as well as different postprocessing methods (multiplanar reconstruction, volume-rendering technique, 3D DSA, and conventional 2D angiography) for their ability to exactly size 2 aneurysm models. Two aneurysm models with known aneurysm sizes were placed inside a human skull. After injection of iodine contrast media, imaging was performed using a 128-slice CT scanner or an Artis Q biplane angiosuite, respectively. Aneurysms were measured for width, neck, and height, and the mean difference from the known sizes was calculated for each technique. The technique with the most exact measurement was defined as the criterion standard. We performed Bland-Altman plots comparing all techniques against the criterion standard. Angiograms adjusted according a previous 3D run with a short object-to-detector distance resulted in the most exact aneurysm measurement: -0.07 ± 0.61 mm for aneurysm 1 and 0.17 ± 0.39 mm for aneurysm 2. Measurements of conventional DSA images were similar, and CT-based images were significantly inferior to the criterion standard. 2D DSA with a short objective-to-detector distance adjusted according to a previous 3D run resulted in the most exact aneurysm measurement and should therefore be performed before all endovascular aneurysm treatments.

Prevalence of aortic arch anatomical branching variants in Kenyan population as shown on contrast enhanced chest multidetector computed tomography

Background: The objective of the study was to determine the prevalence of aortic arch(AA) anatomical branching variants present in Kenyan population as shown on a chest contrast-enhanced multidetector computed tomography (MDCT). Methods: The study design was a prospective cross-sectional study carried out in 6 months (between May and November 2016) at the Kenyatta National Hospital(KNH) department of Radiology. Participants were recruited amongst patients referred for a chest contrast enhanced MDCT. Acquired data was subjected to volume rendering technique (VRT) and multiplanar reconstruction (MPR) software to define the anatomy of the AA. The type of AA branching classification used was one derived by Natsis et al. Data analysis involved calculating frequency distributions of AA variations using Statistical Package for Social Sciences version 21 software. Results: One hundred and eighty-five subjects (86 males and 99 females) were recruited. Ninety-five participants had classical AA Natsis type I. Ninety participants had non-classical variant AA of which 83 participants had Natsis type II while 2 patients had Natsis type III. The remaining 3 had a variant AA not found in the Natsis study. Conclusions: Variations in the branching pattern of AA are very common in Kenya with the most common being Natsis type II. Keywords: aortic arch; anatomical variants; branching variation; chest multidetector computed tomography

Investigation of subdural electrode displacement in invasive epilepsy surgery workup using neuronavigation and intraoperative MRI

ABSTRACTObjectives: One of the main obstacles of electrode implantation in epilepsy surgery is the electrode shift between implantation and the day of explantation. We evaluated this possible electrode displacement using intraoperative MRI (iopMRI) data and CT/MRI reconstruction.Methods: Thirteen patients (nine female, four male, median age 26 ± 9.4 years) suffering from drug-resistant epilepsy were examined. After implantation, the position of subdural electrodes was evaluated by 3.0 T-MRI and thin-slice CCT for 3D reconstruction. Localization of electrodes was performed with the volume-rendering technique. Post-implantation and pre-explantation 1.5 T-iopMRI scans were coregistered with the 3D reconstructions to determine the extent of electrode dislocation.Results: Intraoperative MRI at the time of explantation revealed a relevant electrode shift in one patient (8%) of 10 mm. Median electrode displacement was 1.7 ± 2.6 mm with a coregistration error of 1.9 ± 0.7 mm. The median accuracy of the neuronavigation system was 2.2 ± 0.9 mm. Six of twelve patients undergoing resective surgery were seizure free (Engel class 1A, median follow-up 37.5 ± 11.8 months).Conclusion: Comparison of pre-explantation and post-implantation iopMRI scans with CT/MRI data using the volume-rendering technique resulted in an accurate placement of electrodes. In one patient with a considerable electrode dislocation, the surgical approach and extent was changed due to the detected electrode shift.Abbreviations: ECoG: electrocorticography; EZ: epileptogenic zone; iEEG: invasive EEG; iopMRI: intraoperative MRI; MEG: magnetoencephalography; PET: positron emission tomography; SPECT: single photon emission computed tomography; 3D: three-dimensional.

Development of a Dual-Energy Computed Tomography-Based Segmentation Method for Collateral Ligaments: A Porcine Knee Model

The clinical value of dual-energy computed tomography (DECT) has gradually been recognized in many applications. In particular, DECT offers a new imaging method to improve the visualization of ligaments and tendons. However, limitations such as two-dimensional display and manual window adjustment hamper the evaluation of knee ligament injuries. In this study, we proposed a method to segment collateral ligaments from DECT images automatically. Based on various segmentation techniques, collateral ligaments can be visualized using the three-dimensional (3D) volume-rendering technique. To validate our methodology, we used a porcine knee model and focused on the detection of the medial collateral ligament (MCL) and lateral collateral ligament (LCL). Twenty porcine hind legs were scanned using DECT after specimens underwent surgery to cut either the MCL or the LCL. Using the proposed method, either a complete or a partial LCL rupture could be detected clearly, and a complete MCL rupture could be shown clearly. However, some cases might present some difficulty in identifying a partial MCL rupture since the MCL is a thin ligament. The proposed method can be used to automatically segment the main ligaments of the knee. In addition, the 3D volume rendering image makes DECT a valuable tool for the diagnosis of knee ligament injuries.