Iodine-based Contrast Research Articles

Improved visualisation of ACP-engineered osteoblastic spheroids: a comparative study of contrast-enhanced micro-CT and traditional imaging techniques

This study investigates osteoblastic cell spheroid cultivation methods, exploring flat-bottom, U-bottom, and rotary flask techniques with and without amorphous calcium phosphate (ACP) supplementation to replicate the 3D bone tissue microenvironment. ACP particles derived from eggshell waste exhibit enhanced osteogenic activity in 3D models. However, representative imaging of intricate 3D tissue-engineered constructs poses challenges in conventional imaging techniques due to notable scattering and absorption effects in light microscopy, and hence limited penetration depth. We investigated contrast-enhanced micro-CT as a methodological approach for comprehensive morphological 3D-analysis of thein-vitromodel and compared the technique with confocal laser scanning microscopy, scanning electron microscopy and classical histology. Phosphotungstic acid and iodine-based contrast agents were employed for micro-CT imaging in laboratory and synchrotron micro-CT imaging. Results revealed spheroid shape variations and structural integrity influenced by cultivation methods and ACP particles. The study underscores the advantage of 3D spheroid models over traditional 2D cultures in mimicking bone tissue architecture and cellular interactions, emphasising the growing demand for novel imaging techniques to visualise 3D tissue-engineered models. Contrast-enhanced micro-CT emerges as a promising non-invasive imaging method for tissue-engineered constructs containing ACP particles, offering insights into sample morphology, enabling virtual histology before further analysis.

In-line spectroscopy for iodine quantification in dynamic contrast-enhanced dedicated breast CT.

In 4D dynamic contrast-enhanced dedicated breast computed tomography (4D DCE-bCT), the functional properties of the breast will be characterized by monitoring the uptake and washout of iodine-based contrast agents over time. This information could be valuable in breast cancer treatment. However, prior to clinical implementation, it is crucial to validate the quantitative estimates of iodine concentrations at each time point during acquisition. To develop an in-line spectroscopy system capable of measuring iodine concentrations in a dynamic x-ray breast phantom in real-time. Potassium iodide served as the contrast agent. The system was set-up at both the entrance and exit of the phantom. It comprises a fiber-coupled green LED and collimator, which together ensure that a parallel beam passes through the sample holder. Transmitted light is captured by a collimator on the opposite side and directed through a fiber optic cable to a photodetector for intensity measurement. The relationship between 13 iodine concentrations (0-6mg I/mL) and light transmission was tested, and the system's repeatability and accuracy were determined. The system exhibited a strong correlation between iodine concentration and transmission values, achieving a root-mean-square error of 0.007. The repeated measurements had relative standard deviations of 0.04% and 0.1% for repeated water measurements at the phantom's entrance and exit, respectively. Furthermore, the accuracy measurements gave a mean error of fitting of 0.008(±0.07) mg I/mL. The in-line spectroscopy system can effectively monitor iodine concentrations in a dynamic breast phantom, providing a reliable method for quantitative validation of 4D DCE-bCT.

Coronary plaque volume burden and composition in patients with non-hemodynamically significant coronary artery plaques and systemic inflammation

Abstract Introduction Atherosclerotic coronary disease is a leading cause of morbidity and mortality worldwide. Systemic inflammation can affect plaque composition and thus increase cardiovascular risk. Identifying plaque characteristics in these patients could be useful to learn how inflammation (identified by easy to access parameters, like high ferritin and CRP) affects plaque composition in these challenging patients. Purpose We aimed to evaluate the association of systemic inflammation identified by high ferritin and/or high C-reactive protein (CRP) with coronary plaque volume and composition in patients with non-hemodynamically significant coronary artery plaques (stenosis <50%). Methods We prospectively recruited 109 patients referred for noninvasive CT angiography (from November 2023 to January 2024) with suspected coronary artery disease. 20 had totally/partially non-calcified, non-significant coronary plaques (stenosis <50%). Plaque volume was measured. Plaque components were stablished as calcified (>200 UH), lipidic (<60 UH) and fibrous (60-200 UH). Systemic inflammation was identified when ferritin was >300 ng/mL and/or C-reactive protein CRP was >5 mg/L, according to our laboratory high normal limits. CT scan images were acquired with a 128 detectors dual-layer CT scan with prospective-retrospective/synchronization. Intravascular iodine-based contrast agent was administered. Results Mean age was 60 ± 11 years old and 75% of patients were men. 55% had high blood pressure, 65% were current or previous smokers and 40% had dyslipidemia (35% received statins). 10% were diabetic. There were no difference between groups for these characteristics. We analyzed 33 plaques. Fibrous plaque volume was found to be significantly higher in patients with high ferritin (66.9 vs 32.5 mm3; p = 0.04) and in patients with high CRP (78.7 vs 36.4 mm3; p = 0.05). The percentage of fibrous plaque tended to be higher in patients with higher ferritin and CRP (54.9 vs 38.9; p = 0.06 and 60.6 vs 40.7%; p = 0.07, respectively). Conclusions Systemic inflammation affecting coronary plaque composition in non-hemodynamically significant coronary atherosclerotic disease can by identified by high ferritin and high CRP levels. It is associated with higher fibrous plaque volumes. This finding suggest that systemic inflammation can associate more vulnerable plaques and might benefit from more aggressive management of non-hemodynamically significant atherosclerosis.TableFigure

Coronary atherosclerotic plaque burden and characterization by spectral computed tomography scan in patients with high lipoprotein a and non-hemodynamically significant stenosis

Abstract Introduction Atherosclerotic coronary disease increases morbidity and mortality worldwide. Lipoprotein A (LpA) has emerged as a cardiovascular risk marker, but little is known of its direct influence in plaque volume and composition. Spectral computed tomography (CT) technology allows to characterize coronary plaques with new promising tools. Purpose To evaluate the association of LpA with the extent and composition of non-significant coronary plaques producing stenosis <50%. Methods We prospectively recruited 109 patients referred for noninvasive CT angiography (November 2023-January 2024) with suspected coronary artery disease. 20 had totally/partially non-calcified, non-significant coronary plaques. Plaques were segmented and volume was measured. Their composition was stablished as calcified (>200 UH), lipidic (<60 UH) and fibrous (60-200 UH). Spectral data-based plaque parameters were analyzed, including radiological attenuation on polyenergetic images (CTPI), on virtual low/high monoenergetic images (CT40KeV and CT140KeV, respectively), variation in attenuation across monoenergetic levels (slope40-140 KeV) and Z-effective value. CT scan images were acquired with a 128 detectors dual-layer spectral scan with prospective-retrospective/synchronization. Intravascular iodine-based contrast was administered. LpA was stablished as high (≥25 mg/dL) or low (<25 mg/dL). Results Mean age was 60 ± 11. Cardiovascular risk factor were equally distributed between groups. We analyzed 33 plaques. Total plaque volume was significantly higher in high LpA patients (125.9 mm3 vs 62.1 mm3). There were no differences in plaque composition by LpA (Table). Additionally, spectral data showed significantly higher plaque attenuation on CT140KeV images in high LpA patients (36.07 vs 21.32 HU; p = 0.05). There were no differences for the rest of spectral parameters. Conclusions Plaque volume was higher in patients with non-significant atherosclerotic disease and high LpA, but these plaques showed similar composition in high and low LpA patients. These patients might, therefore, respond to the same conventional treatment event though there is not specific treatment for high LpA yet. Additionally, spectral CT140KeV images could add more precision differentiating these plaques since radiological attenuation in these reconstructions is higher in patients with high LpA.TableFigure

Changes in tissues and organs through PMCTA carrier substances.

To date, lipophilic contrast agents mixed with oil, usually paraffin oil, are the most commonly used contrast agents in post-mortem computed tomography angiography (PMCTA). Iodine-based hydrophilic contrast media in combination with a water-soluble carrier, e.g. polyethylene glycol (PEG), are also common. However, their influence on different tissues and organs is poorly understood. In order to analyse the changes in the cadavers caused by the different carrier substances, we evaluated the effects of PEG 200 and oil on the different tissues and organs. Therefore, during a forensic autopsy, liquid femoral vein blood and samples of different organs and vessels were taken and preserved at room temperature in the two liquids mentioned. The condition of the samples was documented during the autopsy and 24, 48 and 72h after preservation. Microscopic examination took place after 72h. After 24h, the samples placed in PEG 200 already showed a clear solidification of almost all structures. Crumbly blood agglomerates had formed in the previously liquid blood. In contrast, the samples stored in oil showed signs of classic cadaveric decomposition after 24h, which increased with time. The microscopic and immunohistochemical evaluation of the samples stored in PEG showed a good diagnostic quality. The analysis of tissues stored in oil was much more difficult due to putrefaction. PEG and oil show significantly different effects on human tissues, mainly conservation and dehydration are affected. It is crucial to be aware of these differences in order to choose the most appropriate PMCTA method for each forensic case.

Gadolinium-based coronary CT angiography on a clinical photon-counting-detector system: a dynamic circulating phantom study

BackgroundCoronary computed tomography angiography (CCTA) offers non-invasive diagnostics of the coronary arteries. Vessel evaluation requires the administration of intravenous contrast. The purpose of this study was to evaluate the utility of gadolinium-based contrast agent (GBCA) as an alternative to iodinated contrast for CCTA on a first-generation clinical dual-source photon-counting-detector (PCD)-CT system.MethodsA dynamic circulating phantom containing a three-dimensional-printed model of the thoracic aorta and the coronary arteries were used to evaluate injection protocols using gadopentetate dimeglumine at 50%, 100%, 150%, and 200% of the maximum approved clinical dose (0.3 mmol/kg). Virtual monoenergetic image (VMI) reconstructions ranging from 40 keV to 100 keV with 5 keV increments were generated on a PCD-CT. Contrast-to-noise ratio (CNR) was calculated from attenuations measured in the aorta and coronary arteries and noise measured in the background tissue. Attenuation of at least 350 HU was deemed as diagnostic.ResultsThe highest coronary attenuation (441 ± 23 HU, mean ± standard deviation) and CNR (29.5 ± 1.5) was achieved at 40 keV and at the highest GBCA dose (200%). There was a systematic decline of attenuation and CNR with higher keV reconstructions and lower GBCA doses. Only reconstructions at 40 and 45 keV at 200% and 40 keV at 150% GBCA dose demonstrated sufficient attenuation above 350 HU.ConclusionCurrent PCD-CT protocols and settings are unsuitable for the use of GBCA for CCTA at clinically approved doses. Future advances to the PCD-CT system including a 4-threshold mode, as well as multi-material decomposition may add new opportunities for k-edge imaging of GBCA.Relevance statementPatients allergic to iodine-based contrast media and the future of multicontrast CT examinations would benefit greatly from alternative contrast media, but the utility of GBCA for coronary photon-counting-dector-CT angiography remains limited without further optimization of protocols and scanner settings.Key PointsGBCA-enhanced coronary PCD-CT angiography is not feasible at clinically approved doses.GBCAs have potential applications for the visualization of larger vessels, such as the aorta, on PCD-CT angiography.Higher GBCA doses and lower keV reconstructions achieved higher attenuation values and CNR.Graphical

Green Synthesis of Silver Nanoparticles Using <i>Citrus sinensis</i> Peels Assisted by Microwave Irradiation as a Contrast Agents for Computed Tomography Imaging

Contrast agents are extensively used to enhance the quality of images in computed tomography (CT) scans for brain exams, vascular imaging, and full-body imaging. Recent data indicate that iodine-based contrast agents have brief durations of blood circulation and may lead to harmful toxicity effects. This study aims to produce silver nanoparticles using environmentally friendly synthesis techniques facilitated by microwaves. The characteristics of nanoparticles have been studied using UV-vis, FTIR, XRD, and TEM techniques. The TEM analysis reveals that the silver nanoparticle has an average diameter of 9 nm and exhibits a spherical shape. The contrast-to-noise ratio (CNR) values of silver nanoparticles at 100, 150, and 200 mg/L concentrations are 35.79, 48.16, and 74.66, respectively. In comparison, iodine exhibits CNR values of 28.57, 34.69, and 48.56 at the same concentrations. The CNR values for tube currents of 140, 160, and 180 mA are 37.83, 44.98, and 48.26, respectively. In contrast, the CNR values in silver nanoparticles are 63.64, 75.32, and 81.67. The results obtained from the different concentrations and tube currents clearly demonstrate that silver nanoparticles have a higher CNR than iopamidol. Hence, silver nanoparticles have significant potential as contrast agents.

Comparative evaluation of gold nanoparticles as contrast agent in multimodality diagnostic imaging

A contrast agent is clinically employed to aid the visualization of organs and structures when imaged by radiation based diagnostic imaging modalities. Iodinated contrast agents have been used for decades, but they carry a heightened risk of adverse allergy reactions and contrast-induced nephropathy. This study investigated the contrast enhancement characteristics of gold nanoparticles (AuNPs) through diverse cancer diagnostic imaging modalities as a potential alternative to the iodine-based contrasts. Solutions of 1.9 nm and 15 nm AuNPs, ranging from 3 to 20 mM concentrations, were prepared, alongside a low osmolar non-ionic iodine contrast agent as a control. All samples were scanned and imaged using x-ray computed tomography scanner (CT-Scan), digital mammography, digital radiography, and fluoroscopy modalities. The contrast-to-noise ratio (CNR) was measured to study the relationship between the size, the concentrations, and the influence of the tube voltage over the image contrast enhancement efficacy of the agents. A lower concentration of AuNPs produced lower CNR values. In addition, the 1.9 nm size of AuNPs caused lower CNR than the 15 nm AuNPs when tested with the highest concentration of 20 mM. High CT's HU values for both sizes of AuNPs indicated substantial contrast enhancement compare to iodine. Although the 15 nm AuNPs might set off higher CNR, a better quality of image contrast enhancement was also observed compared to the 1.9 nm AuNPs. The findings also suggested that the contrast enhancement by AuNPs is highly dependent on the modalities' type and x-rays energy. In conclusion, AuNPs could be applied as a contrast agent in various diagnostic imaging modalities representing promising approach in cancer detection particularly in cases of patients having adverse reactions towards the iodine based contrast agents.

#2955 Incidental findings in a renal magnetic resonance imaging study for evaluation of chronic kidney disease in type 2 diabetes population

Abstract Background and Aims Novel Magnetic Resonance Imaging (MRI) techniques are potential methods to non-invasively assess and quantify functional, structural and pathophysiological changes in chronic kidney disease (CKD) that may improve diagnosis, prognosis and treatment of these patients. Advances in imaging techniques are also likely to result in the detection of unexpected and asymptomatic incidental findings. We retrospectively analyzed the overall prevalence of incidental findings in the participants of our previously reported study utilizing a non-contrast multiparametric MRI protocol in patients with type 2 DM (T2DM) as compared to healthy controls. Method The subjects of this sub-study were participants of our original prospective, single-center, observational study, in which several MRI biomarkers were evaluated to differentiate diabetic versus healthy kidneys, and various stages of CKD. A complete medical history and physical examination were performed. The inclusion criteria for the T2DM cohort were: Age 18-70 years, type II DM with CKD staged 3-4 (estimated glomerular filtration rate [eGFR] 15-60 ml/min/1.73 m2, body mass index (BMI) 18-35 and provision of written informed consent. The control group comprised of healthy volunteers who were age- and sex-matched and had the following inclusion criteria: Age 18-70 years, eGFR >80 ml/min/1.73 m2, UACR <30 mmol/g, BMI 18-35 and provision of written informed consent. Exclusion criteria for the diabetic group were any apparent cause/s of CKD other than diabetes, previous kidney transplantation, pregnancy, contraindication for MRI examination, heart failure (NYHA class III or IV), allergies to iodine-based contrast agents. Factors that excluded healthy participants were pregnancy, contraindication for MRI examination, allergy to iodine-based contrast agents and any active or chronic disease/diagnosis. Measured GFR (mGFR) was assessed in all participants using iohexol clearance. An MRI scan using a wide range of non-contrast techniques was performed at baseline. Total scan time for patients did not exceed 45 min per session and no gadolinium-based contrast agents were used in any of the MRI examinations. All patients with incidental findings on MRI were further evaluated and referred to appropriate specialists for management. Results A total of 38 T2DM patients with CKD and 20 age- and gender-matched healthy volunteers who completed the study were included in the analysis. Of the T2DM patients, 2 were found to have CKD stage 2 by mGFR and 36 CKD stages 3–4. Clinically significant incidental findings (excluding 4 cases of renal cysts requiring only follow-up without further intervention) were found in 13 of the 38 (34%) T2DM patients. The most frequent findings were intraductal papillary mucinous neoplasm (IPMN) in 7 patients, followed by 3 cancers (1 case of kidney cancer, 1 bladder cancer and 1 lymphoma) and 3 cases of adrenal gland mass later diagnosed to be benign adenoma on further investigation. In contrast, of the 20 healthy volunteers, 2 (10%) were found to have significant incidental findings, which were IPMN in both. The follow-up duration varied between 2-6 years. The patient with bladder cancer had metastatic disease and died shortly after the diagnosis, the one with kidney cancer is under observation and the one with lymphoma underwent adequate treatment and is under remission. The cases of IPMN are being followed up regularly at our surgical department. Conclusion Clinically important incidental findings on renal MRI appear to be more common in T2DM patients than in healthy volunteers, which would have been missed without MRI examination. Mechanisms for reporting and strategies for dealing with incidental findings need to be taken into account in such investigational imaging studies. The detection of incidental findings also poses various practical and ethical issues. Further larger studies with long-term follow-up are needed to delineate the clinical relevance, natural course and management of such incidental findings.

#1119 Iodine contrast does not contribute to impaired kidney function or need for dialysis

Abstract Background and Aims Imaging diagnostics play a crucial role in the management of patients with acute and critical conditions or suspected underlying disease like infections or malignancy. These examinations are often enhanced by intravenous iodine-based contrast, to improve the imaging quality and the diagnostic accuracy. For long, there has been a conception that these contrast materials are nephrotoxic, but the last decade has provided a significant quantity of modern studies suggesting that this is not the case. The present study evaluates if earlier contrast exposure has contributed to progress in CKD and the need of initiating dialysis treatment in patients who were in maintenance dialysis treatment at the Västerås hospital at the time of inclusion. Method All patients admitted to the dialysis ward in Västerås the 1st of January 2022 were included and copies of all radiology surveys and all lab values from the electronical records for this study population for the last 10 years were extracted to check for contrast exposure. For some patients, this occurred when they were already on maintenance dialysis treatment, others were pre-dialytic at the time or had not yet developed any kidney impairment. For every contrast exposure, we checked the previous creatinine and the earliest creatinine after the examination to check for acute kidney injury, AKI, as defined by KDIGO. As a secondary outcome, we investigated the frequency of examinations where contrast otherwise would be indicated, but was withhold, due to fear of contrast induced AKI. Results In total, 83 patients were included in this study, and among them there were 121 cases of contrast exposure. There were no events of AKI when eGFR was > 30 ml/min. In the subgroup of patients with eGFR < 30 ml/min, but not in dialysis at the time of the examination, there were only 25 cases of contrast exposure, and only one event of AKI, but this was considered largely due to overhydration and decompensated heart failure and resolved with proper treatment. Among the patients already in dialysis, there were 65 contrast exposures, and no event where any subjects lost their residual kidney function due to contrast induced AKI. In the meantime, there were 249 examinations where contrast material was withheld due to low eGFR, even though it normally would be indicated by the reason of the examination. Conclusion There was none significant event of potential contrast induced AKI among the patients in our study and no patient had any lasting impact on their kidney function from contrast exposure. Contrast exposure does not seem to be a common contributing cause of progressing to end stage renal disease. This is well in line with previous, modern observation studies, suggesting that the risk of contrast induced nephropathy is overrated or possible even a myth. Perhaps even more importantly, contrast enhancement was often inadequately withheld, even though it normally would be necessary to accurately make the diagnosis that was the purpose of ordering the study. Poor imaging quality limits the ability to make correct diagnoses, resulting in substandard treatment for the CKD-population.

Time conditioning for arbitrary contrast phase generation in interventional computed tomography

Minimally invasive ablation techniques for renal cancer are becoming more popular due to their low complication rate and rapid recovery period. Despite excellent visualisation, one drawback of the use of computed tomography (CT) in these procedures is the requirement for iodine-based contrast agents, which are associated with adverse reactions and require a higher x-ray dose. The purpose of this work is to examine the use of time information to generate synthetic contrast enhanced images at arbitrary points after contrast agent injection from non-contrast CT images acquired during renal cryoablation cases. To achieve this, we propose a new method of conditioning generative adversarial networks with normalised time stamps and demonstrate that the use of a HyperNetwork is feasible for this task, generating images of competitive quality compared to standard generative modelling techniques. We also show that reducing the receptive field can help tackle challenges in interventional CT data, offering significantly better image quality as well as better performance when generating images for a downstream segmentation task. Lastly, we show that all proposed models are robust enough to perform inference on unseen intra-procedural data, while also improving needle artefacts and generalising contrast enhancement to other clinically relevant regions and features.

Carbon-coated (Eu/Dy-Enabled) erbium hydroxide nanostructures for biomedical imaging

Lanthanides possess versatile optical and magnetic properties, making them an excellent candidate for multimodal imaging. This study focuses on carbon-coated Erbium Hydroxide Nanoparticles (Er(OH)3 NPs), their cytotoxicity, and their potential for biomedical imaging. Er(OH)3 NPs were synthesized via a simple solvothermal method with the incorporation of different lanthanide dopants (Eu, Dy) to enhance the optical and magnetic properties. The spherical morphology, monodispersity, elemental composition, and effective carbon coating were demonstrated using characterizations such as SEM, EDS, and DLS. These monodisperse NPs were further evaluated for their cytotoxicity in Hep2c cervical cancer cells via colorimetric assays, thus proving carbon coating effectively reduces the cytotoxicity. Photoluminescence data of these NPs show multiple emission peaks with a maximum peak at 433 nm when excited at 253 nm. Magnetic resonance imaging (MRI), and computed tomography (CT) scans of these NPs were carried out to evaluate the multimodal imaging potential as contrast agents. The CT contrast shows comparable results to those of iodine-based contrast agents while the MRI scans of the carbon-coated samples show T2-weighted contrast. These findings provide insights into the potential use of Lanthanide-Enabled Er(OH)3 NPs (LEENs) as multimodal contrast agents.

Evaluation of hafnium oxide nanoparticles imaging characteristics as a contrast agent in X-ray computed tomography.

This research aimed to compare the quantitative imaging attributes of synthesized hafnium oxide nanoparticles (NPs) derived from UiO-66-NH2(Hf) and two gadolinium- and iodine-based clinical contrast agents (CAs) using cylindrical phantom. Aqueous solutions of the studied CAs, containing 2.5, 5, and 10mg/mL of HfO2NPs, gadolinium, and iodine, were prepared. Constructed within a cylindrical phantom, 15cc small tubes were filled with CAs. Maintaining constant mAs, the phantom underwent scanning at tube voltage variations from 80 to 140 kVp. The CT numbers were quantified in Hounsfield units (HU), and the contrast-to-noise ratios (CNR) were calculated within delineated regions of interest (ROI) for all CAs. The HfO2NPs at 140 kVp and concentration of 2.5mg/ml exhibited 2.3- and 1.3-times higher CT numbers than iodine and gadolinium, respectively. Notably, gadolinium consistently displayed higher CT numbers than iodine across all exposure techniques and concentrations. At the highest tube potential, the maximum amount of the CAs CT numbers was attained, and at 140 kVp and concentration of 2.5mg/ml of HfO2NPs the CNR surpassed iodine by 114%, and gadolinium by 30%, respectively. HfO2NPs, as a contrast agent, demonstrated superior image quality in terms of contrast and noise in comparison to iodine- and gadolinium-based contrast media, particularly at higher energies of X-ray in computed tomography. Thus, its utilization is highly recommended in CT.

CEM immediately after contrast-enhanced CT: a one-step staging of breast cancer

BackgroundContrast-enhanced mammography (CEM) is a promising technique. We evaluated the diagnostic potential of CEM performed immediately after contrast-enhanced computed tomography (CE-CT).MethodsFifty patients with breast cancer underwent first CE-CT and then CEM without additional contrast material injection. Two independent radiologists evaluated CEM images. The sensitivity of CEM for detecting index and additional malignant lesions was compared with that of mammography/ultrasonography by the McNemar test, using histopathology as a reference standard. Interobserver agreement for detection of malignant lesions, for classifying index tumors, and for evaluating index tumor size and extent was assessed using Cohen κ. Pearson correlation was used for correlating index tumor size/extent at CEM or mammography/ultrasonography with histopathology.ResultsOf the 50 patients, 30 (60%) had unifocal disease while 20 (40%) had multicentric or multifocal disease; 5 of 20 patients with multicentric disease (25%) had bilateral involvement, for a total of 78 malignant lesions, including 72 (92%) invasive ductal and 6 (8%) invasive lobular carcinomas. Sensitivity was 63/78 (81%, 95% confidence interval 70.27–88.82) for unenhanced breast imaging and 78/78 (100%, 95.38–100) for CEM (p < 0.001). The interobserver agreement for overall detection of malignant lesions, for classifying index tumor, and for evaluating index tumor size/extent were 0.94, 0.95, and 0.86 κ, respectively. For index tumor size/extent, correlation coefficients as compared with histological specimens were 0.50 for mammography/ultrasonography and 0.75 for CEM (p ≤ 0.010).ConclusionsCEM acquired immediately after CE-CT without injection of additional contrast material showed a good performance for local staging of breast cancer.Relevance statementWhen the CEM suite is near to the CE-CT acquisition room, CEM acquired immediately after, without injection of additional contrast material, could represent a way for local staging of breast cancer to be explored in larger prospective studies.Key points• CEM represents a new accurate tool in the field of breast imaging.• An intravenous injection of iodine-based contrast material is required for breast gland evaluation.• CEM after CE-CT could provide a one-stop tool for breast cancer staging.Graphical

IDDSI-compliant recipes containing oral contrast agents for radiological dysphagia diagnostics.

Videofluoroscopic swallowing study (VFSS), alongside flexible endoscopic evaluation of swallowing, represents the gold standard for diagnosing swallowing disorders and to determine severity, pathophysiology, and effective interventions, including texture modification. The clinical swallowing examination and assessment supplements these instrumental methods and serves as the basis for the modules of swallowing diagnostics. The adaptation of food and drink consistencies in dysphagia management has become widespread. For valid results of a VFSS with respect to confirming swallowing safety and efficiency of different liquid and food consistencies and textures, the use of uniform recipes containing radio-opaque contrast media is important. Our goal was to identify recipes that would produce consistencies that conform to the liquid and food levels of 0-7, as defined by the International Dysphagia Diet Standardization Initiative (IDDSI), with barium- and iodine-based contrast media, xanthan gum-based thickeners, and other edible components, which also show sufficient contrast on VFSS. In this study, we determined the different recipes using IDDSI testing methods and explored their radiological characteristics using a Philips MultiDiagnost Eleva fluoroscopy system and two different fluid contrast agents: barium- (Micropaque®) and iodine-based (Telebrix®). All recipes showed sufficient contrast on fluoroscopy and could be visualized in the amounts used for swallowing examinations. They were practical and easy to implement in terms of production and availability of the components. The homogeneity of the recipes diminished with higher IDDSI levels, which represent transitional food, but appeared still sufficient for fluoroscopic examination. The opacity did not significantly differ between the barium- and iodine-based contrast media.

Seizures Associated with Povidone-Iodine Impregnated Antral Pack in a Child: a Case Report and Review of Literature

This is a case of 11 years-old patient diagnosed of suppurative osteomyelitis of the right maxilla. He had incision and drainage with sequestrectomy under general anaesthesia, and povidone-iodine-impregnated antra pack. About 60 hours after surgery, patient began to have seizures, about 6 episodes on the first night, generalized, tonic-clonic, each lasting about 1 minute with post-ictal vomiting. An initial assessment of meningitis (to rule out cerebral abscess) was made. The seizure episodes which lasted for 3 days began to reduce gradually, and completely subsided 24 hours after the removal of the antra pack. However, when the patient had a CT scan with iodine-based contrast as requested by the paediatric neurologist (to rule out cerebral abscess), the episodes went up significantly again for another 24 hours, after which it began to reduce, till none was recorded 48 hours after contrast administration. Povidone-Iodine (PVI) slowly liberates free iodine to exhibit its broad range of microbicidal activity. However, depending on the amount of iodine absorbed, there is a possibility of iodine toxicity, with different systemic manifestations including seizures, especially in children. The seizure is believed to be a result of disruption in the blood-brain barrier by free iodine from PVI and the iodine-based contrast media. Therefore caution should be taken in using PVI as an antiseptic agent in antra packs or on any mucosa surface, especially in children.&#x0D;

Spectral computed tomography angiography using a gadolinium-based contrast agent for imaging of pathologies of the aorta

ObjectivesEspecially patients with aortic aneurysms and multiple computed tomography angiographies (CTA) might show medical conditions which oppose the use of iodine-based contrast agents. CTA using monoenergetic reconstructions from dual layer CT and gadolinium (Gd-)based contrast agents might be a feasible alternative in these patients. Therefore, the purpose of this study was to evaluate the feasibility of clinical spectral CTA with a Gd-based contrast agent in patients with aortic aneurysms.MethodsTwenty-one consecutive scans in 15 patients with and without endovascular aneurysm repair showing contraindications for iodine-based contrast agents were examined using clinical routine doses (0.2 mmol/kg) of Gd-based contrast agent with spectral CT. Monoenergetic reconstructions of the spectral data set were computed.ResultsThere was a significant increase in the intravascular attenuation of the aorta between pre- and post-contrast images for the MonoE40 images in the thoracic and the abdominal aorta (p < 0.001 for both). Additionally, the ratio between pre- and post-contrast images was significantly higher in the MonoE40 images as compared to the conventional images with a factor of 6.5 ± 4.5 vs. 2.4 ± 0.5 in the thoracic aorta (p = 0.003) and 4.1 ± 1.8 vs. 1.9 ± 0.5 in the abdominal aorta (p < 0.001).ConclusionsTo conclude, our study showed that Gd-CTA is a valid and reliable alternative for diagnostic imaging of the aorta for clinical applications. Monoenergetic reconstructions of computed tomography angiographies using gadolinium based contrast agents may be a useful alternative in patients with aortic aneurysms and contraindications for iodine based contrast agents.

Monolacunary Wells-Dawson Polyoxometalate as a Novel Contrast Agent for Computed Tomography: A Comprehensive Study on In Vivo Toxicity and Biodistribution.

Polyoxotungstate nanoclusters have recently emerged as promising contrast agents for computed tomography (CT). In order to evaluate their clinical potential, in this study, we evaluated the in vitro CT imaging properties, potential toxic effects in vivo, and tissue distribution of monolacunary Wells-Dawson polyoxometalate, α2-K10P2W17O61.20H2O (mono-WD POM). Mono-WD POM showed superior X-ray attenuation compared to other tungsten-containing nanoclusters (its parent WD-POM and Keggin POM) and the standard iodine-based contrast agent (iohexol). The calculated X-ray attenuation linear slope for mono-WD POM was significantly higher compared to parent WD-POM, Keggin POM, and iohexol (5.97 ± 0.14 vs. 4.84 ± 0.05, 4.55 ± 0.16, and 4.30 ± 0.09, respectively). Acute oral (maximum-administered dose (MAD) = 960 mg/kg) and intravenous administration (1/10, 1/5, and 1/3 MAD) of mono-WD POM did not induce unexpected changes in rats' general habits or mortality. Results of blood gas analysis, CO-oximetry status, and the levels of electrolytes, glucose, lactate, creatinine, and BUN demonstrated a dose-dependent tendency 14 days after intravenous administration of mono-WD POM. The most significant differences compared to the control were observed for 1/3 MAD, being approximately seventy times higher than the typically used dose (0.015 mmol W/kg) of tungsten-based contrast agents. The highest tungsten deposition was found in the kidney (1/3 MAD-0.67 ± 0.12; 1/5 MAD-0.59 ± 0.07; 1/10 MAD-0.54 ± 0.05), which corresponded to detected morphological irregularities, electrolyte imbalance, and increased BUN levels.

Safety of Administering Intravenous CT Contrast Agents Repeatedly or Using Both CT and MRI Contrast Agents on the Same Day: An Animal Study.

To investigate molecular and functional consequences of additional exposures to iodine- or gadolinium-based contrast agents within 24 hours from the initial intravenous administration of iodine-based contrast agents through an animal study. Fifty-six Sprague-Dawley male rats were equally divided into eight groups: negative control, positive control (PC) with single-dose administration of CT contrast agent, and additional administration of either CT or MR contrast agents 2, 4, or 24 hours from initial CT contrast agent injection. A 12 µL/g of iodinated contrast agent or a 0.47 µL/g of gadolinium-based contrast agent were injected into the tail vein. Serum levels of blood urea nitrogen, creatinine, cystatin C (Cys C), and malondialdehyde (MDA) were measured. mRNA and protein levels of kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) were evaluated. Levels of serum creatinine (SCr) were significantly higher in repeated CT contrast agent injection groups than in PC (0.21 ± 0.02 mg/dL for PC; 0.40 ± 0.02, 0.34 ± 0.03, and 0.41 ± 0.10 mg/dL for 2-, 4-, and 24-hour interval groups, respectively; P < 0.001). There was no significant difference in the average Cys C and MDA levels between PC and repeated CT contrast agent injection groups (Cys C, P = 0.256-0.362; MDA, P > 0.99). Additional doses of MR contrast agent did not make significant changes compared to PC in SCr (P > 0.99), Cys C (P = 0.262), and MDA (P = 0.139-0.771) levels. mRNA and protein levels of KIM-1 and NGAL were not significantly different among additional CT or MR contrast agent groups (P > 0.05). A sufficient time interval, probably more than 24 hours, between repeated contrast-enhanced CT examinations may be necessary to avoid deterioration in renal function. However, conducting contrast-enhanced MRI on the same day as contrast-enhanced CT may not induce clinically significant kidney injury.

Model-based approach for analysis of contrast media regions in contrast enhanced breast model images

Contrast agents in radiology improve visualisation and iodine-based ones are applied in differ- ent radiology techniques. Energies, used in these techniques, vary in a very wide range. The energies can be as low as 26 kVp in mammography and reach up to 140 - 150 kVp in computed tomography. Dual-energy studies can also be applied. X-ray images of resin phantoms with iodine-based contrast base are taken at different energies and the image pixel values of various regions of interest were measured. Based on the performed measurements, the visual contrast between the studied different areas is calculated and analysed. The obtained data are applied for the estimation of models for the expected pixel values depending on the energies and the contrast agent quantities. These models can be used to describe the real conditions, which differ from the applicable to theoretical calculations ideal conditions.