Contrast-enhanced X-ray Imaging Research Articles

Computed tomography in the diagnosis of oncopathology in end-stage renal disease: A case report

BACKGROUND: In recent years, an increasing tendency of oncopathology in patients with chronic kidney disease (CKD) was observed. Clinical data demonstrate an increased risk of malignization in patients with decreased renal function. The cohort study (2022) reported a cumulative incidence of cancer in nephrology patients ranging from 10.8% to 15.3%. A high percentage of stage IV cancers were detected in patients with CKD at the time of diagnosis. In 2022, the American Association for Cancer Research published the results of a Mendelian Randomization Study examining the causal relationship between CKD and the risk of developing 19 local cancers, including renal cell cancer, cervical cancer, leukemia, and colorectal cancer. Several studies found a direct correlation between a decreased glomerular filtration rate and the development of oncopathologies. Therefore, cancer awareness is important in the management of patients with CKD. In patients with end-stage chronic renal disease (ESRD) who are on hemodialysis, X-ray diagnosis with iodine-containing radiopaque agents is possible without additional risk of kidney damage.
 AIM: To demonstratу the role of computed tomography (CT) in the diagnosis of oncopathology in a patient with CKD to attract the attention of physicians to the importance of using advanced diagnostic techniques in patients with CKD.
 METHODS: A clinical case of a 32-year-old patient M. who was hospitalized in the Therapeutic Department of Multidisciplinary City Hospital No. 2 in Astana was presented.
 RESULTS: A patient with ESRD resulting from chronic glomerulonephritis in a hypertensive form complained of dyspnea at rest, cough with difficult sputum, right thoracic pain, general weakness, and weight loss of 8 kg in 1 month. Past medical history showed that the patient was on alternate program hemodialysis for 4 years. Deterioration occurred within 3 months. The patient was examined at the place of residence. CT scan showed signs of tuberculosis of the upper right lobe (?) and lymphadenopathy of intrathoracic and axillary lymph nodes. A neoplasm was not excluded. The patient was consulted by a phthisiatrician, GeneXpert sputum was performed, and tuberculosis was excluded. In dynamics, ultrasound was conducted due to increasing dyspnea. Fluid accumulation in the pericardial and pleural cavities was detected. A pulmonologist assessed the situation as uremic pericarditis, pleurisy on the right side, and right-sided pneumonia in the upper lobe of unclear genesis. Antibacterial therapy was prescribed. Due to a significant deterioration of the condition, the patient went to the city hospital. At admission, respiratory failure, pain syndrome in the chest area, and marked asthenization up to cachexia were observed. Ultrasound of pleural cavities showed free fluid in the pleural cavity on the right (770 ml) and left (110 ml), whereas abdominal ultrasound revealed cavernous hemangiomas of the liver (?), echogenic suspension of the gallbladder, and splenomegaly. Echocardiography showed diffuse hypokinesis of all left ventricular walls. Grade 12 pulmonary hypertension was detected. Systolic function of the left ventricle was moderately decreased. Effusion in the pericardial cavity in the volume of 430 ml and congestion in the inferior vena cava were found. A patient with ESRD was on program hemodialysis for 4 years, which allowed the use of contrast-enhanced X-ray imaging techniques without the risk of additional renal damage. Contrast-enhanced chest CT showed pronounced right-sided pleurisy. Given the presence of foci of contrast agent accumulation in the structure of the parietal pleura, malignancy was not excluded (mesothelioma?). Indolent left-sided pleurisy, segmental and subsegmental compression atelectasis of the right lung, distinct edema and thickening of interlobular septa of both lungs, and single dense foci of I/II, III segments of the left lung up to 4.2 mm in diameter were detected. In addition, chronic bronchitis, pericarditis, and lymphadenopathy of subclavian, intrathoracic, and axillary lymph nodes up to 15.0 mm in diameter (malignancy not excluded) were revealed. Osteosclerosis foci of the Th3 vertebral body measuring 4.75.1 mm was observed. Contrast-enhanced abdominal and retroperineal CT scan showed a focal mass of the IVa segment of the liver measuring 17.315.916.4 mm (malignancy not excluded), chronic calculous cholecystitis, chronic pancreatitis, lymphadenopathy of intra-abdominal para-aortic and mesenteric lymph nodes up to 18.0 mm in size (malignancy not excluded), reduced size of both kidneys (contracted kidneys), and a cystic mass in the left ovary measuring 39.442.034.5 mm (35 HU). Patient was consulted by an oncologist: pleural mesothelioma? Metastasis in the liver? Consultation with a thoracic surgeon to decide on morphological verification was recommended. A biopsy was planned at the place of residence; however, morphological verification of oncopathology was not performed due to the patients lethal outcome.
 CONCLUSIONS: This clinical case of a patient with ESRD on hemodialysis demonstrates the importance of contrast-enhanced CT to diagnose oncopathology.

Morphological and Chemical Investigation of Ovarian Structures in a Bovine Model by Contrast-Enhanced X-ray Imaging and Microscopy

An improved understanding of an ovary's structures is highly desirable to support advances in folliculogenesis knowledge and reproductive medicine, with particular attention to fertility preservation options for prepubertal girls with malignant tumors. Although currently the golden standard for structural analysis is provided by combining histological sections, staining, and visible 2D microscopic inspection, synchrotron radiation phase-contrast microtomography is becoming a new challenge for three-dimensional studies at micrometric resolution. To this aim, the proper use of contrast agents can improve the visualization of internal structures in ovary tissues, which normally present a low radiopacity. In this study, we report a comparison of four staining protocols, based on iodine or tungsten containing agents, applied to bovine ovarian tissues fixed in Bouin's solution. The microtomography (microCT) analyses at two synchrotron facilities under different set-ups were performed at different energies in order to maximize the image contrast. While tungsten-based agents allow large structures to be well identified, Iodine ones better highlight smaller features, especially when acquired above the K-edge energy of the specific metal. Further scans performed at lower energy where the setup was optimized for overall quality and sensitivity from phase-contrast still provided highly resolved visualization of follicular and intrafollicular structures at different maturation stages, independent of the staining protocol. The analyses were complemented by X-ray Fluorescence mapping on 2D sections, showing that the tungsten-based agent has a higher penetration in this type of tissues.

Non-radioactive imaging strategies for in vivo immune cell tracking.

In vivo tracking of administered cells chosen for specific disease treatment may be conducted by diagnostic imaging techniques preceded by cell labeling with special contrast agents. The most commonly used agents are those with radioactive properties, however their use in research is often impossible. This review paper focuses on the essential aspect of cell tracking with the exclusion of radioisotope tracers, therefore we compare application of different types of non-radioactive contrast agents (cell tracers), methods of cell labeling and application of various techniques for cell tracking, which are commonly used in preclinical or clinical studies. We discuss diagnostic imaging methods belonging to three groups: (1) Contrast-enhanced X-ray imaging, (2) Magnetic resonance imaging, and (3) Optical imaging. In addition, we present some interesting data from our own research on tracking immune cell with the use of discussed methods. Finally, we introduce an algorithm which may be useful for researchers planning leukocyte targeting studies, which may help to choose the appropriate cell type, contrast agent and diagnostic technique for particular disease study.

Current Techniques of Intravascular Imaging and Implantation of Bioresorbable Coronary Vascular Scaffolds (Stents)

Introduction. The use of intravascular imaging techniques, in particular intravascular ultrasound, makes it possible to reduce the number of subsequent revascularisations. The method of optical coherence tomography (ОСТ), due to its high resolution accuracy, makes it possible to establish and assess the edge dissection, stent thrombosis, tissue prolapse, and strut fracture and malposition. This paper aims to assess the impact of routine use of OCT on long term outcomes in patients with scaffolds implanted.Materials and methods. 32 stenting procedures with the use of bioresorbable coronary intravascular scaffolds (Absorb, Abbot Vascular) were performed in 2014-2015 with subsequent visualisation and assessment with optical coherence tomography. In the control group (n=16) scaffolds were implanted without the use of OCT under traditional contrast enhanced X-ray imaging. The analysis of the combination of outcomes that included subsequent emergency revascularisation in the target artery, cardiac death, myocardial infarction and 12 months post-op OCT imaging data, served as the end.Results. The total of 55 BVS were implanted, 22 in the OCT group and 23 in control. Suboptimal results were registered in eight cases out of 16 in the OCT group (50%). These included: one dissection and atherosclerotic plaque prolapse — implantation of a second BVS and postdilatation, one eccentric stent expansion — a model for acute thrombosis, resolved with postdilatation, and stent underexpansion in the remaining six. Once the OCT revealed the intima dissection following predilatation; this was stabilised with the implantation of a second scaffold. The examination results at 12 months follow up established that there were 3.215 more scaffold restenoses in the control group.Conclusion. The cutting edge technique of intravascular revascularisation with bioresorbable coronary scaffolds requires careful preparation and intraoperative control. The results of our study support the use of intravascular imaging techniques as methods of choice for the assessment of the expansion, areas of dissection, thrombosis and scaffold eccentricity.

Low-Dose Contrast-Enhanced Breast CT Using Spectral Shaping Filters: An Experimental Study.

Iodinated contrast-enhanced X-ray imaging of the breast has been studied with various modalities, including full-field digital mammography (FFDM), digital breast tomosynthesis (DBT), and dedicated breast CT. Contrast imaging with breast CT has a number of advantages over FFDM and DBT, including the lack of breast compression, and generation of fully isotropic 3-D reconstructions. Nonetheless, for breast CT to be considered as a viable tool for routine clinical use, it would be desirable to reduce radiation dose. One approach for dose reduction in breast CT is spectral shaping using X-ray filters. In this paper, two high atomic number filter materials are studied, namely, gadolinium (Gd) and erbium (Er), and compared with Al and Cu filters currently used in breast CT systems. Task-based performance is assessed by imaging a cylindrical poly(methyl methacrylate) phantom with iodine inserts on a benchtop breast CT system that emulates clinical breast CT. To evaluate detectability, a channelized hoteling observer (CHO) is used with sums of Laguerre-Gauss channels. It was observed that spectral shaping using Er and Gd filters substantially increased the dose efficiency (defined as signal-to-noise ratio of the CHO divided by mean glandular dose) as compared with kilovolt peak and filter settings used in commercial and prototype breast CT systems. These experimental phantom study results are encouraging for reducing dose of breast CT, however, further evaluation involving patients is needed.

A versatile x-ray microtomography station for biomedical imaging and materials research.

An x-ray microtomography station implemented at the X-ray Applied Crystallography Laboratory of the State University of Campinas is described. The station is based on a propagation based phase contrast imaging setup with a microfocus source and digital x-ray area detectors. Due to its simplicity, this setup is ideal for fast, high resolution imaging and microtomography of small biological specimens and materials research samples. It can also be coupled to gratings to use and develop new techniques as the harmonic spatial coherent imaging, which allow scattering contrast imaging. Details of the experimental setup, equipment, and software integration are described. Test microtomography for setup commissioning and characterization is shown. We conclude that phase contrast enhanced x-ray imaging and microtomography with resolution below 5 μm voxel size are possible and data sets as wide as 2000 × 2000 × 2000 voxels are obtained with this instrumentation.

The application of phase contrast X-ray techniques for imaging Li-ion battery electrodes

In order to accelerate the commercialization of fuel cells and batteries across a range of applications, an understanding of the mechanisms by which they age and degrade at the microstructural level is required. Here, the most widely commercialized Li-ion batteries based on porous graphite based electrodes which de/intercalate Li+ ions during charge/discharge are studied by two phase contrast enhanced X-ray imaging modes, namely in-line phase contrast and Zernike phase contrast at the micro (synchrotron) and nano (laboratory X-ray microscope) level, respectively. The rate of charge cycling is directly dependent on the nature of the electrode microstructure, which are typically complex multi-scale 3D geometries with significant microstructural heterogeneities. We have been able to characterise the porosity and the tortuosity by micro-CT as well as the morphology of 5 individual graphite particles by nano-tomography finding that while their volume varied significantly their sphericity was surprisingly similar. The volume specific surface areas of the individual grains measured by nano-CT are significantly larger than the total volume specific surface area of the electrode from the micro-CT imaging, which can be attributed to the greater particle surface area visible at higher resolution.

Characterization of the Arterial Anatomy of the Murine Hindlimb: Functional Role in the Design and Understanding of Ischemia Models

RationaleAppropriate ischemia models are required for successful studies of therapeutic angiogenesis. While collateral routes are known to be present within the innate vasculature, there are no reports describing the detailed vascular anatomy of the murine hindlimb. In addition, differences in the descriptions of anatomical names and locations in the literature impede understanding of the circulation and the design of hindlimb ischemia models. To understand better the collateral circulation in the whole hindlimb, clarification of all the feeding arteries of the hindlimb is required.ObjectiveThe aim of this study is to reveal the detailed arterial anatomy and collateral routes in murine hindlimb to enable the appropriate design of therapeutic angiogenesis studies and to facilitate understanding of the circulation in ischemia models.Methods and ResultsArterial anatomy in the murine hindlimb was investigated by contrast-enhanced X-ray imaging and surgical dissection. The observed anatomy is shown in photographic images and in a schema. Previously unnoticed but relatively large arteries were observed in deep, cranial and lateral parts of the thigh. The data indicates that there are three collateral routes through the medial thigh, quadriceps femoris, and the biceps femoris muscles. Furthermore, anatomical variations were found at the origins of the three feeding arteries.ConclusionsThe detailed arterial anatomy of murine hindlimb and collateral routes deduced from the anatomy are described. Limitations on designs of ischemia models in view of anatomical variations are proposed. These observations will contribute to the development of animal studies of therapeutic angiogenesis using murine hindlimb ischemia models.

X射线相衬成像法在线表征冷冻靶技术

A brief review of X-ray phase contrast imaging theory for spherical objects is given. Using Tracepro, simulated X-ray phase-contrast images of SiO2/DD cryogenic capsules are produced. The ability of phase contrast enhanced X-ray imaging for characterization of cryogenic fuel layers inside ablator shells has been proven with the simulation result. X-ray phase contrast imaging equipment has been established for characterization of cryogenic targets, with which imaging experiments for low density divinyl benzene foam shells and SiO2/DD cryogenic capsules have been carried out, and phase contrast images of cryogenic DD fuel layers in SiO2 capsules are obtained, with a resolution up to 1.5 m. Ablator and cryogenic fuel layers can be simultaneously characterized by X-ray phase contrast imaging.

Optimization of a dual‐energy contrast‐enhanced technique for a photon‐counting digital breast tomosynthesis system: I. A theoretical model

Dual-energy (DE) iodine contrast-enhanced x-ray imaging of the breast has been shown to identify cancers that would otherwise be mammographically occult. In this article, theoretical modeling was performed to obtain optimally enhanced iodine images for a photon-counting digital breast tomosynthesis (DBT) system using a DE acquisition technique. In the system examined, the breast is scanned with a multislit prepatient collimator aligned with a multidetector camera. Each detector collects a projection image at a unique angle during the scan. Low-energy (LE) and high-energy (HE) projection images are acquired simultaneously in a single scan by covering alternate collimator slits with Sn and Cu filters, respectively. Sn filters ranging from 0.08 to 0.22 mm thickness and Cu filters from 0.11 to 0.27 mm thickness were investigated. A tube voltage of 49 kV was selected. Tomographic images, hereafter referred to as DBT images, were reconstructed using a shift-and-add algorithm. Iodine-enhanced DBT images were acquired by performing a weighted logarithmic subtraction of the HE and LE DBT images, The DE technique was evaluated for 20-80 mm thick breasts. Weighting factors, w(t) that optimally cancel breast tissue were computed. Signal-difference-to-noise ratios (SDNRs) between iodine-enhanced and nonenhanced breast tissue normalized to the square root of the mean glandular dose (MGD) were computed as a function of the fraction of the MGD allocated to the HE images. Peak SDNR/ mean square root of MGD and optimal dose allocations were identified. SDNR/ mean square root of MGD and dose allocations were computed for several practical feasible system configurations (i.e., determined by the number of collimator slits covered by Sn and Cu). A practicalsystem configuration an d Sn-Cu filterpair that accounts for the trade-off between SDNR, tube-output, and MGD were selected. w(t) depends on the Sn-Cu filter combination used, as well as on the breast thickness; to optimally cancel 0% with 50% glandular breast tissue, w(t) values were found to range from 0.46 to 0.72 for all breast thicknesses and Sn-Cu filter pairs studied. The optimal w(t) values needed to cancel all possible breast tissue glandularites vary by less than 1% for 20 mm thick breasts and 18% for 80 mm breasts. The system configuration where one collimator slit covered by Sn is alternated with two collimator slits covered by Cu delivers SDNR/ mean square root of MGD nearest to the peak value. A reasonable compromise is a 0.16 mm Sn-0.23 mm Cu filter pair, resulting in SDNR values between 1.64 and 0.61 and MGD between 0.70 and 0.53 mGy for 20-80 mm thick breasts at the maximum tube current. A DE acquisition technique for a photon-counting DBT imaging system has been developed and optimized.

A new approach for contrast-enhanced X-ray imaging of the left atrium and pulmonary veins for atrial fibrillation ablation: rotational angiography during adenosine-induced asystole

Atrial fibrillation ablation is a complex procedure that requires detailed anatomic information about left atrium (LA) and pulmonary veins (PVs). The goal of this study was to test rotational angiography of the LA during adenosine-induced asystole as an imaging tool in patients undergoing atrial fibrillation ablation. Seventy patients with paroxysmal or persistent atrial fibrillation undergoing PV isolation were included. After transseptal puncture, adenosine (30 mg) was given intravenously, and during atrioventricular block, contrast medium was directly injected in the LA; a rotational angiography was performed (right anterior oblique 55 degrees to left anterior oblique 55 degrees). Rotational angiography images were assessed qualitatively in all patients and quantitatively in 45 patients in comparison with computed tomography (CT) images. The majority of rotational angiography imaging data (94%) were deemed at least 'useful' in delineating the LA-PV anatomy. The so-called 'ridge' between left superior PV and left atrial appendage was delineated in 90% of the patients. All accessory PVs were independently identified by rotational angiography and CT. A blinded quantitative comparison of PV ostial diameters showed an excellent correlation between rotational angiography and CT measurements (r > 0.90 for all PVs). No serious adverse effects occurred in association with adenosine. Intra-procedural contrast-enhanced rotational angiography of the LA-PV during adenosine-induced asystole is feasible and provides anatomical information of high diagnostic value for atrial fibrillation ablation.

Quantitative characterization of inertial confinement fusion capsules using phase contrast enhanced x-ray imaging

Current designs for inertial confinement fusion capsules for the National Ignition Facility consist of a solid deuterium–tritium (D–T) fuel layer inside of a copper doped beryllium, Be(Cu), shell. Phase contrast enhanced x-ray imaging is shown to render the D–T layer visible inside the Be(Cu) shell. Phase contrast imaging is experimentally demonstrated for several surrogate capsules and validates computational models. Polyimide and low density divinyl benzene foam shells were imaged at the Advanced Photon Source synchrotron. The surrogates demonstrate that phase contrast enhanced imaging provides a method to characterize surfaces when absorption imaging cannot be used. Our computational models demonstrate that a rough surface can be accurately characterized using phase contrast enhanced x-ray images.