Innovative Imaging Techniques Research Articles

The CAM Assay as an Alternative In Vivo Model for Drug Testing.

In the last decade, the chicken chorioallantoic membrane (CAM) assay has been re-discovered in cancer research to study the molecular mechanisms of anti-cancer drug effects. Literature about the CAM assay as an alternative in vivo cancer xenograft model according to the 3R principles has exploded in the last 3years. Following a summary of the basic knowledge about the chicken embryo, we compare advantages and disadvantages with the classical mouse xenograft model, exemplify established and innovative imaging techniques that are used in the CAM model, and give examples of its successful utilization for studying major hallmarks of cancer such as angiogenesis, proliferation, invasion, and metastasis.

Imaging the adenovirus infection cycle.

Incoming adenoviruses seize control of cytosolic transport mechanisms to relocate their genome from the cell periphery to specialized sites in the nucleoplasm. The nucleus is the site for viral gene expression, genome replication, and the production of progeny for the next round of infection. By taking control of the cell, adenoviruses also suppress cell-autonomous immunity responses. To succeed in their production cycle, adenoviruses rely on well-coordinated steps, facilitated by interactions between viral proteins and cellular factors. Interactions between virus and host can impose remarkable morphological changes in the infected cell. Imaging adenoviruses has tremendously influenced how we delineate individual steps in the viral life cycle, because it allowed the development of specific optical markers to label these morphological changes in space and time. As technology advances, innovative imaging techniques and novel tools for specimen labeling keep uncovering previously unseen facets of adenovirus biology emphasizing why imaging adenoviruses is as attractive today as it was in the past. This review will summarize past achievements and present developments in adenovirus imaging centered on fluorescence microscopy approaches.

Bioinspired Cell Nuclear Nanotransporters Generated by Self-Assembly of Amphiphilic Polysaccharide-Amino Acid Derivatives Conjugates.

Development of nanomaterials that surely transport functional biomacromolecules and bioactive synthetic compounds into the cell nucleus must be promising for the generation of nuclear-targeting new technologies. However, the development of nuclear transporting nanomaterials thus still remains a significant challenge, because molecular transport between the cytoplasm and the nucleus of a eukaryotic cell is strictly regulated by the sole gateway through the nuclear envelope, the nuclear pore complexes (NPCs). Here, the rational design of novel artificial nuclear nanotransporters (NucPorters), inspired by importin, naturally occurring nuclear transporters is shown. The NucPorter is generated by simple molecular design: self-assembly of amphiphilic polymers, where a few numbers of hydrophobic amino-acid derivatives with phenyl groups are conjugated to negatively charged hydrophilic heparin. The NucPorter can mimic essential structural and chemical features of importin machinery to pass through the NPCs. Importantly, the NucPorter demonstrates remarkable rapid and high efficient nuclear transport in cultured cells, tissue/organ, and living mice. Moreover, the NucPorter successfully imports both enzymes and synthetic anticancer drugs into the nucleus while maintaining their bioactivity. Thus, the NucPorter provides a promising new route to generate innovative nuclear-targeting medicines, diagnostics, cell imaging and engineering techniques, and drug delivery systems.

FTIR, Raman and AFM characterization of the clinically valid biochemical parameters of the thrombi in acute ischemic stroke

The significance and utility of innovative imaging techniques in arterial clot analysis, which enable far more detailed and automated analysis compared to standard methods, are presented. The examination of two types of human thrombi is shown, representing the main ischemic stroke etiologies: fibrin–predominant clot of large vessel origin and red blood cells–rich clot of cardioembolic origin. The synergy effect of Fourier–transform infrared spectroscopy (FTIR), Raman spectroscopy (RS) and atomic force microscopy (AFM) techniques supported by chemometrics in comparison with reference histological staining was presented. The main advantage of such approach refers to free–label and non–destructive quantitative imaging of clinically valid, biochemical parameters in whole sample (FTIR–low resolution) and selected regions (RS–ultra–high resolution). We may include here analysis of lipid content, its distribution and total degree of unsaturation as well as analysis of protein content (mainly fibrin and hemoproteins). The AFM studies enhanced the vibrational data, showed clearly shape and thickness of clot features as well as visualized the fibrin framework. The extraordinary sensitivity of FTIR and RS imaging toward detection and discrimination of clinically valid parameters in clot confirms its applicability in assessment of thrombi origin.

Intra-Operative 3-Dimensional Imaging (O-arm) in Foot and Ankle Trauma Surgery: Report of 2 Cases and Review of the Literature

Background: Intraoperative two-dimensional (2D) fluoroscopy is the standard imaging modality available to orthopaedic surgeons worldwide. It is well-accepted, however, multiplanar 3 dimensional (3D) CT scanning is superior to 2D imaging for visualising joint surfaces and is now a fundamental feature of the pre-operative planning of intra-articular fractures. Objective: We present two cases in which the use of 3D intraoperative imaging and the O-arm® (Medtronic, Minneapolis, USA) led to immediate intraoperative revision to optimise fixation and articular congruity. A review of the current literature is also provided. Methods: During the trial period of the O-arm at our major trauma centre, intra-operative imaging was used in the lower limb trauma setting. The O-arm was used intra-operatively in a comminuted pilon fracture and a displaced talus fracture. We recorded all the intra-operative events, including quality of reduction, implant positioning and operation time. Each patient was followed-up for 12 months post-operation and was finally assessed with x-rays and the AOFAS score. Results: In both the cases, either fracture reduction or the implant position/usage that was observed with 2D fluoroscopy was revised following a 3D intra-operative scan. No postoperative complications were noted and the healing process was uneventful. X-rays at the final follow-up were excellent and acceptable for the talus and pilon fracture, respectively, with corresponding clinical results and AOFAS score. Conclusion: Although frequently used in spinal surgery, to the best of our knowledge, the use of intra-operative 3D techniques in lower limb trauma is sparse and sporadically reported. We present our cases in which the most current innovative imaging techniques influenced intra-operative outcomes without compromising patient safety. We feel that this is a real example of how innovation can positively influence patient care.

Current Status in Testing for Nonalcoholic Fatty Liver Disease (NAFLD) and Nonalcoholic Steatohepatitis (NASH).

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries with almost 25% affected adults worldwide. The growing public health burden is getting evident when considering that NAFLD-related liver transplantations are predicted to almost double within the next 20 years. Typically, hepatic alterations start with simple steatosis, which easily progresses to more advanced stages such as nonalcoholic steatohepatitis (NASH), fibrosis and cirrhosis. This course of disease finally leads to end-stage liver disease such as hepatocellular carcinoma, which is associated with increased morbidity and mortality. Although clinical trials show promising results, there is actually no pharmacological agent approved to treat NASH. Another important problem associated with NASH is that presently the liver biopsy is still the gold standard in diagnosis and for disease staging and grading. Because of its invasiveness, this technique is not well accepted by patients and the method is prone to sampling error. Therefore, an urgent need exists to find reliable, accurate and noninvasive biomarkers discriminating between different disease stages or to develop innovative imaging techniques to quantify steatosis.

Muographic Observation of Density Variations in the Vicinity of Minami-Dake Crater of Sakurajima Volcano

Muography is an innovative imaging technique used for inspecting and monitoring density-length variations of large-sized natural or human-made objects based on the measurement of the absorption rate of cosmic-ray muons. The first large-sized, high-resolution muography observatory based on Multi-Wire Proportional Chamber (MWPC) technology is being developed to monitor the mass density variations in the vicinity of Minami-dake crater of Sakurajima volcano. We found that the track rates provided by five ongoing tracking systems with a total surface area of 4 m2 are stable within ±3% from the backward direction, which demonstrates that the MWPC-based Muographic Observation System (MMOS) is applicable for the detection of average density variations above 2%, which is well below the practical limit of 5%. We quantified the time resolution of the designed muography observatory by modeling the muon flux across the volcano; the average density-length variation of 5 (10)% is expected to be detected within 5–20 (2–8) days at a 1σ (68%) confidence level (CL) with an MMOS orientation of 10.86° above the horizon. An automated analysis framework was developed as a data base for raw data reconstruction, analysis, and preparation, and which is accessible via web-server. We observed a more than 2σ CL decrease in average density across the West side of Crater A during the ongoing data collection period. The observed density decrease suggests that the amount of material has decreased inside Crater A due to the consecutive eruptions of Minami-dake during the data collection period from November 30, 2018 to January 11, 2019.

Mitigation of Temperature Gradients in the Buffer Tank of a Natural Circulation Loop Simulating Passive Decay Heat Removal in a Pool Type Reactor

This study considers the decay heat removal through passive systems (i.e., natural convection) in the pool-type experimental reactor MYRRHA (SCK•CEN). The low velocities associated with natural convection may cause a degradation of the thermal mixing in the upper plenum of the reactor: buoyancy dominated phenomena, such as stratification, buoyant jets or convective cells may occur. The large temperature gradients associated with these phenomena may induce thermal loads on the structure, compromising its integrity. The objectives of this work are, in order, (1) achieving an understanding of the fluid mechanics leading to the formation of thermal gradients in the upper plenum and (2) mitigating the temperature gradients the upper plenum’s geometry. The methodology chosen to address the problem is experimental. A ''two-dimensional'' water facility modeling a slab of the reactor's primary loop was designed. Simultaneous measurements of velocity and temperature were performed in the model's buffer tank using thermocouples and innovative optical imaging techniques. It was observed that vertical thermal gradients develop in the tank because of the combined effect of stratification and advection. Important reductions of local gradients were observed when changing porosity and position of upper plenum’s buffer plates.

In vivo multifunctional optical coherence tomography at the periphery of the lungs.

Remodeling of tissue, such as airway smooth muscle (ASM) and extracellular matrix, is considered a key feature of airways disease. No clinically accepted diagnostic method is currently available to assess airway remodeling or the effect of treatment modalities such as bronchial thermoplasty in asthma, other than invasive airway biopsies. Optical coherence tomography (OCT) generates cross-sectional, near-histological images of airway segments and enables identification and quantification of airway wall layers based on light scattering properties only. In this study, we used a custom motorized OCT probe that combines standard and polarization sensitive OCT (PS-OCT) to visualize birefringent tissue in vivo in the airway wall of a patient with severe asthma in a minimally invasive manner. We used optic axis uniformity (OAxU) to highlight the presence of uniformly arranged fiber-like tissue, helping visualizing the abundance of ASM and connective tissue structures. Attenuation coefficient images of the airways are presented for the first time, showing superior architectural contrast compared to standard OCT images. A novel segmentation algorithm was developed to detect the surface of the endoscope sheath and the surface of the tissue. PS-OCT is an innovative imaging technique that holds promise to assess airway remodeling including ASM and connective tissue in a minimally invasive, real-time manner.

Additional Value of Superb Microvascular Imaging for Thyroid Nodule Classification with the Thyroid Imaging Reporting and Data System

Superb microvascular imaging (SMI) is an innovative vascular imaging technique for ultrasound (US). Compared with conventional color Doppler imaging (CDI) and power Doppler imaging (PDI), SMI can detect more blood flow in thyroid nodules. In this study, a total of 203 thyroid nodules (160 benign nodules, 43 malignant nodules) in 195 patients were assessed with the Thyroid Imaging Reporting and Data System (TI-RADS) published by the American College of Radiology in 2017) and SMI. With TI-RADS alone, 24 (15.0%), 76 (47.5%), 65 (40.6%) and 39 (24.4%) thyroid nodules were classified as TR2, TR3, TR4 and TR5, respectively. However, with the combination of TI-RADS and SMI, 31 (19.4%), 79 (49.4%), 44 (27.5%) and 49 (30.6%) thyroid nodules were classified as TR2, TR3, TR4 and TR5, respectively. The area under the receiver operating characteristic curves for the combination (0.952) was larger than that for TI-RADS alone (0.883) (Z = 3.478, p = 0.001). The efficiency of TI-RADS alone and the TI-RADS + SMI combination in diagnosing thyroid nodules was determined for all except TR2 nodules. Although no significant differences between the methods were observed for TR3 and TR5 thyroid nodules (p > 0.05), the diagnostic efficiency of TI-RADS + SMI for TR4 thyroid nodules was higher than that of TI-RADS alone for TR4 nodules (p < 0.05). This study indicated that the vascularity of thyroid nodules can be well characterized using SMI, and the combined use of gray-scale US and SMI can improve the diagnostic performance of TI-RADS for TR4 thyroid nodules.

Mitochondrial Rich Proton Pumping Cells in the Kidney and Epididymis are Highly Glycolytic

The kidney collecting duct (CD) has a crucial role in regulating acid‐base balance. Alpha intercalated cells (ICs) of the CD maintain acid‐base homeostasis by acidifying the urine, via apical V‐ATPase H+ pumps. ICs are characterized in appearance by a very high density of mitochondria, but remarkably little is known about metabolism in these cells, due to a lack of suitable techniques to study this and the inability to generate a stable IC cell line. By using different innovative imaging techniques, we aimed to better understand how metabolism might be adapted in ICs to their specialized H+ pumping function.Using multiphoton microscopy of intact murine kidney slices, we have found that mitochondria in ICs have some highly unusual features compared with other tubular cells. IC mitochondria are considerably more mobile and dynamic, and display a high NADH signal but low uptake of voltage dependent dyes. Moreover, they are energized by a pH gradient that is functionally coupled to the proton pumping activity of the V‐ATPase. However, high resolution confocal microscopy and 3D electron microscopy (FIB‐SEM) in fixed mouse kidney tissue revealed that the mitochondria and V‐ATPase expressing vesicles were distant from each other, reducing the likelihood that the mitochondria are the only energy source for the V‐ATPase H+ pumps in ICs. Furthermore, we observed that the expression of respiratory chain complex V (ATP synthase) is lower in ICs than in surrounding cells, implying reduced oxidative capacity. Conversely, expression of enzymes in the glycolytic pathway, including lactate dehydrogenase, was markedly higher in ICs, consistent with high anaerobic ATP‐generating capacity. Interestingly, expression of glycolytic enzymes was also high in clear cells in the epididymis, suggesting that this is a common feature of proton pumping cells.As a surrogate of cellular ATP levels, we imaged cytosolic Ca2+ in kidney slices using a fluorescent reporter (GcaMP6s), and found that inhibition of mitochondrial ATP production with cyanide produced striking rises in Ca2+ in all tubular cell types except ICs. However, Ca2+ also increased in ICs when glycolysis was simultaneously inhibited. Finally, direct functional measurement of V‐ATPase function in microperfused isolated outermedullary collecting ducts (OMCDs) revealed that inhibition of glycolysis leads to a significant decrease in H+ pumping in ICs.In summary, we have provided several lines of evidence that mitochondrial rich cells in the kidney and epididymis are surprisingly glycolytic, and that glycolysis is functionally important for V‐ATPase activity. These findings provide new insights into coupling of transport and metabolism in proton pumping cells.Support or Funding InformationThis research is supported by The Swiss National Centre for Competence in Research Kidney Control of Homeostasis.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Photoluminescence Imaging for Buried Defects Detection in Silicon: Assessment and Use-Cases

In this paper, the innovative photoluminescence imaging technique is described for applications to buried defect detection in silicon devices. The validity of this emerging technique is first assessed in comparison with well-established characterization techniques (defect selective etching of silicon, X-Ray diffraction topography, cross-sectional transmission electron microscopy imaging and photoluminescence spectroscopy). This paper then describes specific applications illustrating the use of the photoluminescence imaging technique for common processes of the CMOS semiconductor industry. The benefit of this fast, high resolution and non-destructive technique is demonstrated: this includes industrial use of the technique for in-line production control on product wafers.

Influence of Vibration Waveform on MR Elastography

The purpose of this study was to investigate an influence of vibration waveform on magnetic resonance elastography (MRE). MRE is an innovative imaging technique for the non-invasive quantification of the elasticity of soft tissues through the direct visualization of propagating shear waves in vivo using a special phase-contrast magnetic resonance imaging sequence. Since the elasticity of soft tissue calculates from the wavelength of propagating shear waves, it is necessary to propagate sine-wave-shape shear wave at the target soft tissue. However, due to the various factors; i.e. overload of vibration generator, poor contact between imaging object and vibration pad, etc.; it may be difficult to generate a simple sine wave. This work was focused on change vibration waveforms; i.e. square wave, triangle wave, saw-tooth wave; which is induced by the various factors. Phantom experimental results demonstrated that when square and saw-tooth waveforms of 25 Hz vibration frequency, into the phantom, the waveform of propagating wave was not similar to sine waveform. It may influence on the MRE that in case of the waveforms has low frequency and square or saw-tooth like waveforms.

Fully Automated Lumen Segmentation Method for Intracoronary Optical Coherence Tomography

Background Optical coherence tomography (OCT) is an innovative imaging technique that generates high-resolution intracoronary images. In the last few years, the need for more precise analysis regarding coronary artery disease to achieve optimal treatment has made intravascular imaging an area of primary importance in interventional cardiology. One of the main challenges in OCT image analysis is the accurate detection of lumen which is significant for the further prognosis. Method In this research, we present a new approach to the segmentation of lumen in OCT images. The proposed work is focused on designing an efficient automatic algorithm containing the following steps: preprocessing (artifacts removal: speckle noise, circular rings, and guide wire), conversion between polar and Cartesian coordinates, and segmentation algorithm. Results The implemented method was tasted on 667 OCT frames. The lumen border was extracted with a high correlation compared to the ground truth: 0.97 ICC (0.97–0.98). Conclusions Proposed algorithm allows for fully automated lumen segmentation on optical coherence tomography images. This tool may be applied to automated quantitative lumen analysis.

Whole-body magnetic resonance imaging (WB-MRI) in oncology: recommendations and key uses.

The past decade has witnessed a growing role and increasing use of whole-body magnetic resonance imaging (WB-MRI). Driving these successes are developments in both hardware and software that have reduced overall examination times and significantly improved MR imaging quality. In addition, radiologists and clinicians have continued to find promising new applications of this innovative imaging technique that brings together morphologic and functional characterization of tissues. In oncology, the role of WB-MRI has expanded to the point of being recommended in international guidelines for the assessment of several cancer histotypes (multiple myeloma, melanoma, prostate cancer) and cancer-prone syndromes (Li-Fraumeni and hereditary paraganglioma-pheochromocytoma syndromes). The literature shows growing use of WB-MRI for the staging and follow-up of other cancer histotypes and cancer-related syndromes (including breast cancer, lymphoma, neurofibromatosis, and von Hippel-Lindau syndromes). The main aim of this review is to examine the current scientific evidence for the use of WB-MRI in oncology.

The use of indocyanine green imaging technique in patient with hepatocellular carcinoma.

Near-infrared indocyanine green (ICG) fluorescence application in liver cancer surgery have been reported in the literature since 2008. To date, most reports emphasized not only to the safety, feasibility and reproducibility, but also the potential benefits of its clinical applications in term of demarcating segmentation for an anatomical resection, tumor identification to achieve tumor free resection margin, detection of small unidentifiable subcapsular nodules as well as extrahepatic metastatic lesions, and fluorescence cholangiography. The purpose of this review is to present the fundamental concept of the interpretation of fluorescence enhancement by different timing through intravascular ICG distribution to liver and biliary washout; to describe step-by-step technical aspects of its use in different purposes, and to expose the diagnostic and therapeutic perspectives of this innovative imaging technique in liver cancer surgery.

Accelerating anticancer drug development - opportunities and trade-offs.

The traditional approach to drug development in oncology, with discrete phases of clinical testing, is becoming untenable owing to expansion of the precision medicine paradigm, whereby patients are stratified into multiple subgroups according to the underlying cancer biology. Seamless approaches to drug development in oncology hold great promise of accelerating the accessibility of novel therapeutic agents to the public but are also accompanied by important trade-offs, including the limited availability of information on the clinical benefit and safety of novel agents at the time of market entry. In this Perspectives article, we describe several opportunities, in the form of novel trial designs or modelling strategies, to improve the efficiency of drug development in oncology, as well as new mechanisms to obtain information about anticancer therapies throughout their life cycle, such as innovative functional imaging techniques or the use of real-world clinical data.

Potential benefit of a simultaneous, side-by-side display of contrast MDCT and echocardiography over routine sequential imaging for assessment of adult congenital heart disease: A preliminary study

BackgroundManagement of adult congenital heart disease (ACHD) patients requires understanding of its complex morphology and functional features. An innovative imaging technique has been developed to display a virtual multi-planar reconstruction obtained from contrast-enhanced multidetector-computed tomography (MDCT) corresponding to the same cross-sectional image from transthoracic echocardiography (TTE). The aim of this study is to assess the usefulness of this imaging technology in ACHD patients. MethodsThis study consisted of 46 consecutive patients (30 women; mean age, 52±18 years old) with ACHD who had undergone contrast MDCT. All patients underwent TTE within a week of MDCT. An experienced sonographer who did not know the results of MDCT conducted a diagnosis using TTE and, then, using the new imaging technology. We studied whether this imaging technology provided additional or unexpected findings or makes more accurate diagnosis. ResultsIn this imaging technology, MDCT cross-section provides higher-resolution image to the deep compared to corresponding TTE image. Depending on the MDCT section which can be arbitrarily set under the echo guide, we can diagnose unexpected or incremental lesions or more accurately assess the severity of the lesion in 27 patients (59%) compared to TTE study alone. This imaging technology was useful in the following situations:1.For anatomical guidance for Doppler flow assessment.2.Assessment of morphology of obstruction in outflow tracts or conduit.3.To clarify the etiology of unordinary severe valvular disease.4.Assessment of the patient with diseased prosthetic valves. ConclusionsThis integrated imaging technology provides incremental role over TTE in complex anatomy, and allows functional information in ACHD patients.

Precise Navigation of the Surgical Plane with Intraoperative Real-time Virtual Sonography and 3D Simulation in Liver Resection

The precise intraoperative navigation of the surgical plane remains challenging in liver surgery; however, an innovative imaging technique—real-time virtual sonography (RVS)—may provide a solution. In this modality, preoperative three-dimensional (3D) resection simulation data are transmitted to an RVS workstation and can be used in combination with intraoperative ultrasound to navigate the surgical plane in real time. This paper describes this technique and our experiences in detail. From November 2015 to March 2017, 26 patients with primary liver cancer underwent liver resection under RVS navigation. The operative procedures employed included hemihepatectomy, bisegmentectomy, segmentectomy, and limited resection. RVS was utilized uneventfully and successfully in each operation. The median time required for spatial position registration was 3 (1–12) min, and as the case volume increased, the time required for registration markedly decreased. The surgical plane under RVS navigation was consistent with that of the preoperative plan, and the resection margin was confirmed negative in each case. In conclusion, RVS in combination with 3D simulation is a feasible, safe, and promising technique for the precise intraoperative navigation of liver resection for primary liver cancer. It could be applied to other resectable liver diseases and may be utilized in other centers.

Enhanced reconstruction algorithm for moiré artifact suppression in Talbot–Lau x-ray imaging

Talbot–Lau x-ray imaging (TLXI) is an innovative and promising imaging technique providing information about the x-ray attenuation, scattering, and refraction features of objects. However, the method is susceptible to vibrations and system component imprecisions, which are inevitable in clinical and industrial practice. Those influences provoke grating displacements and hence errors in the acquired raw data, which cause moiré artifacts in the reconstructed images. We developed an enhanced reconstruction algorithm capable of compensating these errors by adjusting the grating positions and thus suppressing the occurrence of moiré artifacts. The algorithm has been developed with regard to a future application in medical practice. The capability of the algorithm is demonstrated on a medical data set of a human hand (post-mortem) acquired under clinical conditions using a pre-clinical TXLI prototype. It is shown that the algorithm reliably suppresses moiré artifacts, preserves image contrast, does not blur anatomical structures or prevent quantitative imaging, and is executable on low-dose data sets. In addition, the algorithm runs autonomously without the need of interaction or rework of the final results. In conclusion, the proposed reconstruction algorithm facilitates the use of TLXI in clinical practice and allows the exploitation of the method’s full diagnostic potential in future medical applications.