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Background and Purpose Evaluation and treatment of acute ischemic syndromes, in the heart and brain, require vessel visualization by iodinated X‐ray contrast agents. However, these contrast agents can induce injury, in both the kidneys and target organs themselves. Sulfobutylether beta cyclodextrin (SBECD) added to iohexol (SBECD‐iohexol) (Captisol Enabled‐iohexol, Ligand Pharmaceuticals, Inc, San Diego, CA) is currently in clinical trials in cardiovascular procedures, to determine its relative renal safety in high‐risk patients. Preclinical studies showed that SBECD‐iohexol reduced contrast‐induced acute kidney injury in rodent models by blocking apoptosis. The current study was undertaken to determine whether SBECD‐iohexol is also cardioprotective, in the male rat ischemia‐reperfusion model, compared to iohexol alone. Methods After anesthesia, the left coronary artery was ligated for 30 min and the ligation released and reperfusion followed for 2 h prior to sacrifice. Groups 1–4 were injected in the tail vein 10 min prior to ischemia with: (1) vehicle; (2) iohexol; (3) SBECD; and (4) SBECD‐iohexol. Infarct size, hemodynamics, and serum markers were measured. Results An eight‐fold increase in serum creatine kinase in the iohexol‐alone group was observed, compared with no increase in the SBECD‐iohexol group. The mean arterial pressure and rate pressure product were depressed in the iohexol‐alone group, but not in the SBECD‐iohexol group, or controls. No difference in infarct size or serum creatinine among the groups was observed. Conclusion The results of this study suggest that SBECD‐iohexol is superior to iohexol alone, for both the preservation of cardiomyocyte integrity and preservation of myocardial function in myocardial ischemia.

The endovascular perforation (EP) model is a common technique for experimental subarachnoid hemorrhage (SAH) in rats, simulating the pathophysiological features observed in the acute phase of SAH. Due to the drawbacks of large variations in the amount of bleeding, the results obtained from this model require severity evaluation. However, no less-invasive procedure could confirm the precise intracranial conditions immediately after establishing the rat EP model. We created a novel method for evaluating SAH immediately after establishing the rat EP model using intra-arterial contrast-enhanced micro-computed tomography (CT). We administered contrast agents continuously via the carotid artery during surgery and performed CT examination immediately after SAH induction. First, bleeding severity was classified by establishing a scoring system based on the CT findings (cSAH scoring system). Subsequently, we determined the actual SAH distribution macroscopically and histologically and compared it with the cSAH scores. Second, we investigated the contrast agent’s neurotoxicity in rats. Finally, we confirmed the correlation between cSAH scores and SAH severity, including neurological status, cerebral vasospasm, and hematoma volume 24 hr after SAH. Intra-arterial contrast-enhanced micro-CT could visualize the distribution of SAH proportionally to the bleeding severity immediately after establishing the EP model. Moreover, the contrast agent administration was determined not to be neurotoxic to rats. The cSAH scoring revealed a significant correlation with the SAH severity in the rat EP model (P

Metformin as first-line treatment in type 2 diabetes mellitus (T2 D) shows benefits in terms of reducing cardiovascular events, but the risk of a lactic acidosis as a serious adverse event especially in patients with decreased renal function is still relevant. Since the perioperative management of Metformin or its use in diagnostic procedures with contrast agents is inconsistent in literature and different in practice, the results of various guidelines are reviewed below showing the current state of evidence. Despite many guidelines, the evidence on both issues is low, as they are mainly based on consensus recommendations. The guidelines are still based on weak data and many international recommendations have clearly different statements. A fundamental problem with drugs is that expert information does specify eGFR limits for dose reduction, but not the method to be used. Depending on the formula, this can then lead to different treatment decisions. At present, it is not possible to give reliable recommendations for practice with the aim of minimising the interruption of therapy. For this reason, only a strictly conservative approach with 48-hour breaks before and after both measures can be recommended at present. For the situations mentioned in this overview, the question of the right approach has not yet been conclusively and definitely answered, therefore further studies should be carried out.

After an intravenous bolus injection of 100 mL of iodinated contrast agent (370 mgI/mL), the amount of iodine atoms entering the blood is tens of thousands of times the daily dose of iodine recommended by the World Health Organization. However, the effect of iodinated contrast in patients with nonthyroidal illness, manifested as reduced serum total triiodothyronine (TT3) concentrations, is unclear. We studied the effect of iodinated contrast on thyroid function and auto-antibodies in patients with reduced TT3 after diagnosis and treatment of coronary heart disease.This was a prospective cohort study. One hundred and fifty-four stable angina pectoris patients with reduced TT3 and normal thyroid-stimulating hormone (TSH), free thyroxine (FT4), and reverse triiodothyronine (rT3) were enrolled from January, 2017, to June, 2018. All subjects had no history of thyroid dysfunction and had no recent infections, tumors, trauma, or other critical illnesses. Fourty-one patients underwent coronary angiography and 113 patients underwent coronary intervention.There were 6 patients (3.9%) with hypothyroidism and 30 patients (19.5%) developed subclinical hypothyroidism (SCHypo) on the first day after surgery. There were 6 patients (3.9%) with hypothyroidism, 6 patients (3.9%) with SCHypo, and 18 patients (11.7%) with subclinical hyperthyroidism (SCHyper) at the first month postsurgery. There were 23 patients (14.9%) with SCHyper and 6 patients (3.9%) with SCHypo at the sixth month after surgery. No patient with longterm severe thyroid dysfunction occurred during follow-up. The levels of free triiodothyronine, FT4, TT3, total thyroxine, and TSH showed statistically significant changes at 1 day, and 1, 3, and 6 months postoperative (P.005). The level of rT3 showed no statistically significant change at 1, 3, and 6 months postoperative (P.05). The levels of thyroglobulin antibody and thyroid peroxidase antibody decreased at 6 months postoperative (P.001).The risk of subclinical thyroid dysfunction and transient hypothyroidism occurred with a single large dose of iodinated contrast in the diagnosis and treatment of coronary heart disease, but no longterm severe thyroid dysfunction occurred. Patients with preoperative thyroid antibody elevation were more likely to have subclinical thyroid dysfunction after surgery.FT3 = free triiodothyronine; FT4 = free thyroxine; PCI = percutaneous coronary intervention; rT3 = reverse triiodothyronine; SCHyper = subclinical hyperthyroidism; SCHypo = subclinical hypothyroidism; TGAB = thyroglobulin antibody; TPOAB = thyroid peroxidase antibody; TT3 = total triiodothyronine; TT4 = total thyroxine; TSH = thyroid-stimulating hormone; WHO = World Health Organization.

To compare the quantitative and qualitative lung perfusion data acquired with dual energy CT (DECT) to that acquired with a large field-of-view cadmium-zinc-telluride camera single-photon emission CT coupled to a CT system (SPECT-CT).A total of 53 patients who underwent both dual-layer DECT angiography and perfusion SPECT-CT for pulmonary hypertension or pre-operative lobar resection surgery were retrospectively included. There were 30 men and 23 women with a mean age of 65.4±17.5 (SD)years (range: 18-88years). Relative lobar perfusion was calculated by dividing the amount (of radiotracer or iodinated contrast agent) per lobe by the total amount in both lungs. Linear regression, Bland-Altman analysis, and Pearson's correlation coefficient were also calculated. Kappa test was used to test agreements in morphology and severity of perfusion defects assessed on SPECT-CT and on DECT iodine maps with a one-month interval. Wilcoxon rank sum test was used to compare the sharpness of perfusion defects and radiation dose among modalities.Strong correlations for relative lobar perfusion using linear regression analysis and Pearson's correlation coefficient (r=0.93) were found. Bland-Altman analysis revealed a -0.10 bias, with limits of agreement between [-6.01; 5.81]. With respect to SPECT- CT as standard of reference, the sensitivity, specificity, PPV, NPV, accuracy for lobar perfusion defects were 89.4% (95% CI: 82.6-93.4%), 96.5% (95% CI: 92.1-98.5%), 95.6% (95% CI: 90.9-97.8%), 91.4% (95% CI: 85.6-94.9%) and 93.0% (95% CI: 87.6-96.1%) respectively. High level of agreement was found for morphology and severity of perfusion defects between modalities (Kappa=0.84 and 0.86 respectively) and on DECT images among readers (Kappa=0.94 and 0.89 respectively). A significantly sharper delineation of perfusion defects was found on DECT images (P0.0001) using a significantly lower equivalent dose of 4.1±2.3 (SD) mSv (range: 1.9-11.85mSv) compared to an equivalent dose of 5.3±1.1 (SD) mSv (range: 2.8-7.3mSv) for SPECT-CT, corresponding to a 21.2% dose reduction (P=0.0004).DECT imaging shows strong quantitative correlations and qualitative agreements with SPECT-CT for the evaluation of lung perfusion.

Contrast-enhanced ultrasonography (US) has become an important supplementary tool in many clinical applications in children. Contrast-enhanced voiding urosonography and intravenous US contrast agents have proved useful in routine clinical practice. Other applications of intracavitary contrast-enhanced US, particularly in children, have not been widely investigated but could serve as a practical and radiation-free problem-solver in several clinical settings. Intracavitary contrast-enhanced US is a real-time imaging modality similar to fluoroscopy with iodinated contrast agent. The US contrast agent solution is administered into physiological or non-physiological body cavities. There is no definitive list of established indications for intracavitary US contrast agent application. However, intracavitary contrast-enhanced US can be used for many clinical applications. It offers excellent real-time spatial resolution and allows for a more accurate delineation of the cavity anatomy, including the internal architecture of complex collections and possible communications within the cavity or with the surrounding structures through fistulous tracts. It can provide valuable information related to the insertion of catheters and tubes, and identify related complications such as confirming the position and patency of a catheter and identifying causes for drainage dysfunction or leakage. Patency of the ureter and biliary ducts can be evaluated, too. US contrast agent solution can be administered orally or a via nasogastric tube, or as an enema to evaluate the gastrointestinal tract. In this review we present potential clinical applications and procedural and dose recommendations regarding intracavitary contrast-enhanced ultrasonography.

We relay a case of unstable lytic secondary fracture of odontoid process (C2) treated by screw fixation and cementoplasty, using a percutaneous approach. A 62-year-old female patient followed for a breast neoplasia with bone concurrent metastases suffered from diffuse cervical pain. A CT scan showed a lytic fracture of C2. The procedure was performed using CT scan guidance under general anesthesia. After a biphasic enhanced CT scan of the neck and cervical spine, a needle was slowly inserted to hydrodissect the jugulocarotid and prevertebral spaces up to the anterior cortex of C2 using an iodinated contrast agent solution diluted 5% with saline water. Under fluoroscopy guidance and intermittent CT monitoring, a bone pin was navigated though the anterior cortex of C2 and then advanced inside the vertebral body of C2. After checking for optimal positioning of the bone pin, a 34-mm-long titanium screw was inserted into C2 until reaching the posterior cortex. The approach to the transverse fracture line of the body of the odontoid was tangential with no displacement of the bony parts. Cement injection was then performed. One month after the procedure, a CT scan showed no material displacement, and the patient had no visible skin scarring. The patient regained full mobility of the cervical spine, and the pain decreased from 7/10 before the procedure to 0/10 after the procedure according to the patient. Percutaneous screw fixation and cementoplasty to stabilize unstable osteolytic fracture of odontoid process are safe and feasible.

BACKGROUND Kidney transplantation is often complicated by TRAS, and PTRA can effectively treat it. However, PTRA is not appropriate for patients with CKD because iodinated contrast agent may induce nephropathy. METHODS This article reports about a 14-year-old boy with a history of kidney transplantation complicated by RAS. He initially underwent percutaneous balloon dilation to relieve the stenosis. One and half a year after dilation, he received zero-contrast PTRA and stenting under the guidance of external and IVUS with reference to previous PAG image. RESULTS After successful stent implantation, the cross-sectional area of the renal artery lumen was significantly increased.The blood pressure and level of creatinine also decreased and kept stable during follow-up. CONCLUSION This report suggests the feasibility of external ultrasound and IVUS guided, zero-contrast PTRA in patients with poor renal function or iodinated contrast allergy.

International audience; Background The association between the use of potentially nephrotoxic drugs [Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), Iodinated Contrast Agents, Proton Pump Inhibitors (PPIs)] and emergency start of dialysis in patients with chronic kidney disease has not been well explored, although these compounds are commonly prescribed or available without prescription. Methods In this study, the Renal Epidemiology Information Network (REIN) registry data of all patients >= 18 years of age who started dialysis in France in 2015 were matched with those in the French National Health Insurance Database. The association between clinical characteristics, nephrotoxic drug exposure and emergency dialysis start was investigated. Patients were categorized into four classes of NSAID and PPI exposure (new, current, past, no user) on the basis of the pre-dialysis exposure period (1-30, 31-90, and 91-365 days). For iodinated contrast agents, exposure in the 72 h and 7 days before dialysis was analyzed. Results Among the 8805 matched patients, 30.2% needed to start dialysis in emergency. After adjustment for socio-demographic and clinical variables, new NSAID users were more likely to experience emergency dialysis start [OR = 1.95; 95% CI (1.1-3.4)]. This association was higher for new than for current users [OR: 1.44; 95% CI (1.08-1.92)]. Emergency dialysis start was also associated with iodinated contrast agent exposure in the previous 7 days [OR: 1.44; 95% CI (1.2-1.7)]. No significant relationship was detected between PPIs and emergency dialysis start. Conclusions Using both clinical and healthcare data, this study shows that emergency dialysis start is independently associated with recent exposure to NSAIDs and iodinated contrast agents. This suggests the need to strengthen the information given to healthcare professionals and patients with regard to nephrotoxic drugs. [GRAPHICS] .

Background: Carbon dioxide (CO2) exists in nature around us. In the middle of the 20th century, the intraluminal injection of CO2 demonstrated similar results to those of Digital Subtraction Angiography (DSA) with an iodinated contrast agent (ICA). Since then, the technology behind CO2 DSA has developed significantly. Objective: The aim of this study is to inform physicians about the unique properties of CO2 and its physiology after intraluminal injection. Methods: An extensive search for English literature on the properties of CO2 and the physiology of intraluminal administration was conducted using Pubmed. Results: There is sufficient literature on the properties of CO2 and the physiology of CO2 DSA. A review of this literature explains what happens to the human organism after the injection of CO2. Conclusions: There is enough evidence that CO2 DSA is both effective, diagnostic and safe, but the properties of CO2 should be taken under consideration as complications occur, although rarely.

Early detection of osteoarthritis (OA) remains a diagnostic challenge owing to insensitive diagnostic techniques currently available. Herein a new semiquantitative scoring system, based upon contrast-enhanced computed tomographic (CECT) imaging, is described for further refinement of early OA disease staging. Trochlear ridge cartilage defects were surgically created in the femoropatellar joint of an adult horse (ACUC approved protocols). Seven weeks post-surgery, CECT imaging was performed on a clinical scanner after intra-articular injection of a cationic iodinated contrast agent, CA4+, into both injured and control femoropatellar joint compartments. The femoral cartilage surface was densely biopsied, and specimens were assessed for visual (Outerbridge score), functional (equilibrium compressive modulus), and biochemical (glycosaminoglycan content) measures of cartilage quality. Cartilage CECT attenuation was compared with cartilage quality measures using receiver operating characteristic curve analysis to establish attenuation thresholds for distinguishing among cartilage quality levels. CECT imaging identifies macroscopically damaged cartilage regions and in morphologically identical tissue provides moderately sensitive and specific semiquantitative segregation of cartilage quality based upon CECT attenuation, reflecting both glycosaminoglycan content and compressive stiffness of cartilage area under the curve (AUC = 0.83 [95% confidence interval [CI]: 0.72-0.93] for distinguishing poor quality and AUC = 0.76 [95% CI: 0.65-0.90] for distinguishing healthy quality cartilage). A semiquantitative 6-point scoring system-the Osteoarthritis Attenuation and Morphological Assessment (OAMA) score-is proposed as a tool for assessing cartilage quality from CECT images. The OAMA scoring system expands the current disease staging capability of early OA by inclusion of morphological, biochemical, and biomechanical assessments. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2138-2148, 2019.

Transvaginal ultrasound is the first-line examination allowing characterizing 80 to 90% of adnexal masses (LP1). If performed by an expert, a subjective analysis is optimal. If performed by a non-expert, combining the use of Simple Rules with subjective analysis can achieve the diagnostic performance of an expert (LP1). Whichever the chosen model (subjective analysis by an expert or combination of the Simple Rules with a subjective analysis by a non-expert), a second-line examination will have to be proposed in the complex or indeterminate cases (about 20% of the masses) (grade A). The best-performing second-line test for characterization is pelvic MRI (LP1). If read by an expert, a pathological hypothesis can or should be suggested (grade D). In case of non-expert reading, the use of the ADNEXMR score allows a reliable assessment of the positive predictive value of malignancy to guide the patient towards the best management (gradeC). For preoperative assessment and evaluation of resectability of ovarian, fallopian tube or primary peritoneal cancer, it is recommended to perform a chest abdomen and pelvis CT with contrast agent injection (LP2, grade B). In the event of a contraindication to the injection of iodinated contrast agent (severe renal insufficiency, GFR

Contrast InducedNephropathy is the most severe side-effect arising after non-ionic iodinatedcontrast agents (CAs) intravenous administration. The use of antioxidants (i.e.,N-Acetylcysteine; NAC) is one of the attempted prevention approaches. Herein,we describe the microfluidic-assisted synthesis of iodinated polymericnanoparticles (NPs) as new multifunctional blood pool CA. The aim of thisresearch is to co-encapsulate Iohexol (IOX; iodinated CA) and NAC (preventiveagent) into poly-D,L-lactide-co-glycolide (PLGA) and PEGylated-PLGA (PLGA-PEG)NPs to exploit CA diagnostic proprieties and NAC preventing antioxidantactivity. A microfluidic-assisted nanoprecipitation protocol has been set-up forPLGA and PLGA-PEG NPs, evaluating the effect of formulation and microfluidicparameters by analysing the size, PDI and IOX and NAC encapsulation efficiency.The optimized NPs (PLGA-PEG, L:G 50:50, 5% PEG, Mw 90 kDa) formulated with a size of 67±2.8 nm with PDInvitro release study showed an IOX retention into the polymeric matrix andNAC sustained release up to 24-48h stating microfluidics aspowerful tool for the formulation of multifunctional nanoplatforms. Finally, the protective effect ofNPs and NAC were preliminary assessed on human kidney cells.

Objectives To determine the accuracy of an artificial neural network (ANN) for fully automated detection of the presence and phase of iodinated contrast agent in routine abdominal multidetector computed tomography (MDCT) scans and evaluate the effect of contrast correction for osteoporosis screening. Methods This HIPPA-compliant study retrospectively included 579 MDCT scans in 193 patients (62.4 ± 14.6 years, 48 women). Three different ANN models (2D DenseNet with random slice selection, 2D DenseNet with anatomy-guided slice selection, 3D DenseNet) were trained in 462 MDCT scans of 154 patients (threefold cross-validation), who underwent triphasic CT. All ANN models were tested in 117 unseen triphasic scans of 39 patients, as well as in a public MDCT dataset containing 311 patients. In the triphasic test scans, trabecular volumetric bone mineral density (BMD) was calculated using a fully automated pipeline. Root-mean-square errors (RMSE) of BMD measurements with and without correction for contrast application were calculated in comparison to nonenhanced (NE) scans. Results The 2D DenseNet with anatomy-guided slice selection outperformed the competing models and achieved an F1 score of 0.98 and an accuracy of 98.3% in the test set (public dataset: F1 score 0.93; accuracy 94.2%). Application of contrast agent resulted in significant BMD biases (all p p > .05; PV: RMSE 9.45 mg/ml, mean difference 1.28 mg/ml; AR: RMSE 3.98 mg/ml, mean difference 0.94 mg/ml). Conclusion Automatic detection of the contrast phase in multicenter CT data was achieved with high accuracy, minimizing the contrast-induced error in BMD measurements. Key Points • A 2D DenseNet with anatomy-guided slice selection achieved an F1 score of 0.98 and an accuracy of 98.3% in the test set. In a public dataset, an F1 score of 0.93 and an accuracy of 94.2% were obtained. • Automated adjustment for contrast injection improved the accuracy of lumbar bone mineral density measurements (RMSE 18.7 mg/ml vs. 9.45 mg/ml respectively, in the portal-venous phase). • An artificial neural network can reliably reveal the presence and phase of iodinated contrast agent in multidetector CT scans (https://github.com/ferchonavarro/anatomy_guided_contrast_c). This allows minimizing the contrast-induced error in opportunistic bone mineral density measurements.

Post-contrast acute kidney injury (PC-AKI) is defined as acute renal impairment within 48 h following exposure to intravascular iodinated contrast agents (ICAs). Contrast-induced nephropathy (CIN) is an iatrogenic disorder caused by renal degeneration due to ICA exposure. There are several risk factors for CIN, but patients with pre-existing kidney disease and diabetic nephropathy have the greatest risk. Toxicity also depends on the type and the amount of ICM, route of administration, and the number of ICA exposures. The pathogenesis of CIN is multi-factorial and is not fully understood. Identification of patients at risk is an important step in the prevention of CIN. Avoiding the use of ICM, using the lowest possible dose of the ICA, choosing alternative imaging modalities, stopping nephrotoxic drugs, hydration, and pharmacological premedication are proposed.

Introduction: Epidural blood patches (EBPs) are rarely performed at the high-level cervical levels. The aim of the study was to investigate the imaging features, safety, and effectiveness of CT-guided percutaneous EBPs for high-level cervical cerebrospinal fluid (CSF) leakage. Methods: Twenty-five patients with spontaneous high-level (C1–C3) CSF leakage on MRI and CT imaging, including 2 patients with intracranial epidural hematoma caused by CSF, were treated with EBP. Two needles were inserted into the C1–3 bilateral epidural space. The needle location was confirmed by injection of both 3–5mL sterile air and a diluted iodinated contrast agent to delineate its spatial diffusion. The patient’s blood 11.1 ± 3.1 mL was slowly injected to make a patch; the distribution in epidural space was monitored with intermittent CT scanning. Results: The typical manifestation of CSF leakage was the high signal outside the C1–3 cervical dura on MR T2W fat inhibition images and low density in cervical muscle space on CT images. Twenty patients suffered from headaches and were able to sit and walk 24 h after the operation. Four patients, with partial relief of headache and a small but persistent CSF leakage, were re-treated with EBS. One patient underwent a third operation because of a persistent CSF leakage on MRI. Conclusions: Imaging of water at the surrounding epidural space of high cervical level is a typical feature of dural rupture on both MRI and CT. CT-guided EBP is safe and efficient for the high-level cervical CSF leakage, especially for cases in which conservative treatments failed.

Electrical impedance tomography is clinically used to trace ventilation related changes in electrical conductivity of lung tissue. Estimating regional pulmonary perfusion using electrical impedance tomography is still a matter of research. To support clinical decision making, reliable bedside information of pulmonary perfusion is needed. We introduce a method to robustly detect pulmonary perfusion based on indicator-enhanced electrical impedance tomography and validate it by dynamic multidetector computed tomography in two experimental models of acute respiratory distress syndrome. The acute injury was induced in a sublobar segment of the right lung by saline lavage or endotoxin instillation in eight anesthetized mechanically ventilated pigs. For electrical impedance tomography measurements, a conductive bolus (10% saline solution) was injected into the right ventricle during breath hold. Electrical impedance tomography perfusion images were reconstructed by linear and normalized Gauss-Newton reconstruction on a finite element mesh with subsequent element-wise signal and feature analysis. An iodinated contrast agent was used to compute pulmonary blood flow via dynamic multidetector computed tomography. Spatial perfusion was estimated based on first-pass indicator dilution for both electrical impedance and multidetector computed tomography and compared by Pearson correlation and Bland-Altman analysis. Strong correlation was found in dorsoventral (r = 0.92) and in right-to-left directions (r = 0.85) with good limits of agreement of 8.74% in eight lung segments. With a robust electrical impedance tomography perfusion estimation method, we found strong agreement between multidetector computed and electrical impedance tomography perfusion in healthy and regionally injured lungs and demonstrated feasibility of electrical impedance tomography perfusion imaging.

Purpose To examine the frequency and patterns of renal parenchymal retention of iodinated contrast agent during follow-up computed tomography (CT) performed one day after undergoing contrast-enhanced CT and to evaluate the association with the renal function before and after contrast-enhanced CT. Materials and Methods This retrospective study included 55 patients who underwent follow-up CT the day after contrast-enhanced CT had been performed. Two radiologists categorized the retention patterns on a scale of 0–6 (0: no retention, 1: diffuse parenchymal, 2: diffuse cortical, 3: subcapsular tiny nodular, 4: cortical wedge-shaped, 5: medullary focal, 6: renal pelvic). In addition, we collected the patients’ clinical data, including the development of contrast-induced nephropathy (CIN). Results A total of 37 patients (67 %) showed retention of contrast agent in the kidney (retention group), while 18 did not (non-retention group). A diffuse parenchymal pattern and renal pelvis pattern were the most common. High levels of creatinine (Cre) and blood urea nitrogen (BUN) before contrast-enhanced CT were significantly associated with the retention in the kidney (p = 0.018, 0.006, respectively). The frequency of the development of CIN was significantly higher (p = 0.021) in the retention group (10/37) than in the non-retention group (0/18). A diffuse parenchymal pattern and diffuse cortical pattern were significantly more common in patients with CIN than in those without CIN (p = 0.003, p = 0.045, respectively). Conclusion Renal parenchymal retention of iodinated contrast agent the day after contrast-enhanced CT was a frequently recognized finding and was associated with renal dysfunction. This finding, especially diffuse parenchymal and cortical patterns, may be a potential biomarker of CIN development.

Background Transplantation of mesenchymal stem cells (MSCs) is a promising therapy for degenerative spine conditions. However, cell therapy for painful spine degeneration presently requires use of contrast agents during fluoroscopy-guided injections, and the effects of these agents on MSCs represents a gap in knowledge. Objective To investigate the biological effects of contrast media (CM) that are coinjected with MSCs. Design Prospective observational study. Setting Academic medical center. Participants Patient-derived clinical-grade culture expanded MSCs. Interventions Iohexol (Omnipaque300) was reduced to 12.5%, 25%, 50%, and 100% of the stock solution and incubated with MSCs for 30 minutes, 4 hours, and 48 hours. We also used complete media and 12.5%, 25%, 50%, 100% of phosphate-buffered saline as a control group. Main Outcome Measures We examined cytotoxicity of iohexol at different concentrations and exposure duration, as well as the potential for recovery over time. Cell counts, mitochondrial activity, and quantitative real time reverse-transcriptase polymerase chain reaction of related genes were analyzed immediately after exposure (day 0) and after 2 days of exposure (day 2). Results Human MSCs exhibit a time- and concentration-dependent cytotoxic response to iodinated CM. A brief, 30-minute exposure did not affect MSCs function and viability. However, extended treatment with iohexol for 4 hours at 50% or higher concentration had a significant impact on both viability and gene expression in MSCs. Conclusions CM (Omnipaque300) is cytotoxic to MSCs in a time-and concentration-dependent manner. Hence, the concentration of CM that accompanies MSC injections should be carefully considered during MSC therapy for disk-degenerative diseases. Level of Evidence To be determined.

Intracranial aneurysms are increasingly being treated with endovascular therapy, namely coil embolization. Despite being minimally invasive, partial occlusion and recurrence are more frequent compared to open surgical clipping. Therefore, an alternative treatment is needed, ideally combining minimal invasiveness and long-term efficiency. Herein, we propose such an alternative treatment based on an injectable, radiopaque and photopolymerizable polyethylene glycol dimethacrylate hydrogel. The rheological measurements demonstrated a viscosity of 4.86 ± 1.70 mPa.s, which was significantly lower than contrast agent currently used in endovascular treatment (p = 0.42), allowing the hydrogel to be injected through 430 μm inner diameter microcatheters. Photorheology revealed fast hydrogel solidification in 8 min due to the use of a new visible photoinitiator. The addition of an iodinated contrast agent in the precursor contributed to the visibility of the precursor injection under fluoroscopy. Using a customized light-conducting microcatheter and illumination module, the hydrogel was implanted in an in vitro silicone aneurysm model. Specifically, in situ fast and controllable injection and photopolymerization of the developed hydrogel is shown to be feasible in this work. Finally, the precursor and the polymerized hydrogel exhibit no toxicity for the endothelial cells. Photopolymerizable hydrogels are expected to be promising candidates for future intracranial aneurysm treatments., Frontiers in Bioengineering and Biotechnology, 8, ISSN:2296-4185

Iodinated contrast agent is frequently used in computed tomography (CT) imaging to enhance organ contrast enhancement and improve diagnostic sensitivity. Despite this importance, there currently is a lack of standardization in contrast administration protocol across institutions, leading to many safety and clinical diagnostic risks. To solve this, we built three liver contrast enhancement/perfusion models: two using simple linear regression and another by combining a pre-existing pharmacokinetics mathematical model with clinical data with the eventual goal of individualizing contrast administration protocol to optimize contrast-enhanced CT imaging for each patient. These models primarily use patient attributes, such as height, weight, sex, age and contrast administration information, and bolus tracking information to make such predictions. 418 Chest/Abdomen/Pelvis CT scans were used in this study. 75% of cases were used to train these models and the rest were used to test the prediction accuracy. Pearson’s correlation coefficient test was used to find the correlations between the patient attributes and contrast enhancement in liver parenchyma. Weight, height, BMI, and lean body mass were found to be statistically significant predictors for contrast enhancement (P

Purpose To prospectively evaluate contemporary indications, safety and diagnostic impact of cardiac CTA in patients undergoing cardiac CTA examinations for non-coronary clinical indications. Method We analyzed 1097 consecutive patients from the German Cardiac CT Registry who underwent cardiac CTA between 2009 and 2014 due to clinically indicated non-coronary reasons using 64-slice or newer CT systems in twelve tertiary German heart centers in order to evaluate the impact of clinical indications on procedure-associated parameters. All participating centers electronically submitted patient and examination data including detailed indications, clinical symptoms, procedural parameters, complications and diagnostic results in a predefined template. Results The most frequent indication for non-coronary cardiac CTA was the evaluation of pulmonary vein anatomy (65.9 %, 723/1097). In the remaining cases, most frequent indications were planning before TAVI (44.5 %, 69/155), evaluation of valvular disease (31.6 %, 49/155), and evaluation of implants (5.8 %, 9/155). Non-coronary cardiac CTA required a median amount of iodinated contrast agent of 100.0 mL (IQR 95.0–110.0 mL). Prospectively ECG-triggered acquisition was the most frequently used protocol (74.0 %), followed by retrospectively ECG-gated acquisition with and without tube current modulation (19.9 % and 6.0 %, respectively), resulting in a mean estimated effective dose of 5.2 mSv (IQR 2.9−9.5 mSv, average conversion factor k = 0.026). Overall, complication rate was very low (1.5 %). Non-coronary cardiac CTA revealed a new clinical diagnostic aspect in 3.2 % of all patients, and a new main clinical diagnosis in 2.2 %. Conclusions Non-coronary cardiac CTA as a routinely applied diagnostic modality is associated with a very low procedure-related rate of complications and reasonably low radiation exposure using contemporary CT systems.

OBJECTIVE To analyze the incidence of contrast-induced nephropathy in a cohort of patients undergoing computed tomography (CT) with intravenous iodinated contrast material. To evaluate the efficacy of N-acetylcysteine in preventing contrast-induced nephropathy. PATIENTS AND METHODS This prospective observational study was carried out in the months comprising March 2016 through July 2016. We selected the first five patients scheduled to undergo CT examination each day who agreed to participate and signed the informed consent form. We recorded patients' cardiovascular histories, chronic treatments, and indications for the CT examination. We measured blood levels of creatinine and urea before and after the CT examination. We used the Modification of Diet in Renal Disease (MDRD-4) equation to estimate the glomerular filtration rate. We analyzed the type and dose of contrast material. We recorded whether N-acetylcysteine was administered before the CT examination. We used SPSS 15.0® to compare means and proportions. Statistical significance was set at p < 0.05. RESULTS No incidents of contrast-induced nephropathy were detected in any of the 202 patients included [mean age, 63.92 ± 12 years (range 22-87); 57.4% male; 21.8% diabetic; 39.6% hypertensive; 87.1% had MDRD4 ≥ 60 ml/min/1.73 m2 (89.45 ± 14, range 62.36-134.14) and 12.9% had MDRD4 < 60 ml/min/1.73 m2 (45.38 ± 11, range 9.16-58.90)]. The most common indication for CT examinations was oncologic (81.2%). The only contrast agent administered was iopamidol; the mean dose was 107.83 ± 11 ml (range 70-140). The mean interval between pre-CT and post-CT laboratory tests was 4.06 ± 1 days. Only 13 patients received N-acetylcysteine; 9 of these had MDRD

Purpose To assess the underestimation of radiation dose to the thyroid of children undergoing contrast enhanced CT if contrast medium uptake is not taken into account. Methods 161 pediatric head, head & neck and chest CT examinations were retrospectively studied to identify those involving pre- and post-contrast imaging and thyroid inclusion in imaged volume. CT density of thyroid tissue in HU was measured in non-enhanced (NECT) and corresponding contrast-enhanced CT (CECT) images. Resulting CT number increase (ΔHU) was recorded for each patient and corresponded to a % w/w iodine concentration. The relation of %w/w iodine concentration to %dose increase induced by iodinated contrast uptake was derived by Monte Carlo simulation experiments. Results The thyroid gland was visible in 11 chest and 3 neck CT examinations involving both pre- and post-contrast imaging. The %w/w concentration of iodine in the thyroid tissue at the time of CECT acquisition was found to be 0.13%–0.58% w/w (mean = 0.26%). The %increase of dose to thyroid tissue was found to be linearly correlated to%w/w iodine uptake. The increase in radiation dose to thyroid due to contrast uptake ranged from 12% to 44%, with a mean value of 23%. Conclusions The radiation dose to the pediatric thyroid from CECT exposure may be underestimated by up to 44% if contrast medium uptake is not taken into account. Meticulous demarcation of imaged volume in pediatric chest CT examinations is imperative to avoid unnecessary direct exposure of thyroid, especially in CT examinations following intravenous administration of contrast medium.

The study was aimed at evaluation of the feasibility and potential benefit of image fusion (IF) of pre-procedural CT angiography (CTA) and x-ray (XR) fluoroscopy for image-guided navigation in transfemoral transcatheter aortic valve implantation (TAVI) with the strong focus on guiding the double-filter cerebral embolic protection device and valve prosthesis placement. Methods In 31 patients undergoing TAVI, image registration of CTA-derived 3D anatomical models of the relevant cardiac anatomy and vasculature, and live XR was performed applying a commercially available navigation tool. The approach was evaluated in terms of the accuracy of the overlay. In 27 TAVI patients with IF receiving double-filter cerebral embolic protection device overall procedure time, fluoroscopy time, radiation dose, and total volume of intra-procedural iodinated contrast agent (CA) were registered and compared to those of a control group of prospectively enrolled during the same period of time N=27 patients receiving the same protection system but without IF. Results and conclusions Image co-registration and model-based guidance is feasible in TAVI procedures. The overlay facilitates placement of the embolic protection device, placement of the guide wire in the left ventricle and initial alignment of the valve prosthesis prior to final deployment, thus improving the confidence level of the operators during the procedure without compromising CA or XR dose.

Use of X-ray contrast allows us to differentiate between two or more adjacent structures on radiographic studies. The X-ray contrast agent can be the one with increase X-ray absorption, like iodine and a barium X-ray contrast agent or the one with decrease X-ray absorption like air and carbon dioxide contrast agent. Each contrast agent possesses different risks and benefits in various ways. Carbon dioxide as an intravascular contrast agent can be used as an alternative intravascular contrast agent and has superior results in some cases. In patients with renal dysfunction or iodinated contrast allergy, the use of Iodinated Contrast Agent poses the risk of considerable morbidity. Similarly, use of Gadolinium is discouraged in subject with severe renal dysfunction. Use of carbon dioxide (CO2) as an intravascular contrast, offers an alternative in such patients for certain procedures, as it is not nephrotoxic and it does not incite allergic reactions. It is inexpensive, readily available and due to its unique physical properties, it can be used to image a wide variety of vascular beds and chambers. The aim of this paper is to systemically review the current literature to describe the indications, contraindications, adverse effects, instruments, precautions, latest methodologies and data supporting for the use of CO2 as a contrast agent.

Purpose:to analyze the results of preoperative diagnosis and treatment of patients with renal arteriovenous malformation and compare them with the literature data.Materials and methods.5 patients with renal arteriovenous malformations were examined for the period from 2014 to2016 in the FSBI "A.V. Vishnevsky Institute of Surgery» MH RF, where simultaneously there are clinical departments of urology and vascular surgery, 4 of them were treated. All patients were female. The mean age was 31.8 ± 6.7 years (24–41 years). Ultrasound was done to all the patients in B-mode followed by a duplex scan using an abdominal 2–4 MHz convex. MDCT was performed in 4 patients out of 5. Patients underwent multiphase examination on a multidetector CT-scanner Philips Brilliance iCT-256 and Brilliance CT-64 (Philips Medical Systems (Cleveland) with the 120 kV and 100 kV protocols and an intravenous injection of the iodinated contrast agent. Digital subtraction angiography was performed in 3 patients.Results.One-sided lesion occurred in four cases (3 of them (60%) right-sided and 1 (20%) left-sided), in one patient (20%) arteriovenous malformation was bilateral As a result of the analysis of our own material and literature data, the diagnostic criteria of renal arteriovenous malformations according to ultrasound, MDCT and digital subtraction angiography were studied in detail. The results of the examinations of 5 patients with demonstration of ultrasound, MDCT and angiographic images are presented with the visualization of the characteristic features of renal AVM. In addition, the treatment options for such patients with the possibility of preserving the kidney are described.Conclusion.Duplex scanning is an effective method of diagnosis and postoperative follow-up of patients with renal arteriovenous malformations. Preoperative computed tomography and selective digital subtraction angiography provide accurate information about the renal angioarchitectonics and AV-shunts for choosing the treatment tactics and planning the surgical intervention.

Aim To demonstrate the clinical value of prospective electrocardiography (ECG)-triggered cardiac computed tomography (CT) with low concentration contrast medium, low tube voltage, and adaptive statistic iterative reconstruction (ASIR) to reduce both radiation and contrast dose in examining infants with complex congenital heart disease (CHD). Materials and methods Forty-four consecutive infants (19 male, 25 female, age: 8.06±4.33 months, weight: 7.31±1.36 kg) with complex CHD underwent prospective ECG-triggered low-dose cardiac CT using 80 kVp and 120 mA. The contrast agent was iodixanol (270 mg iodine/ml, Visipaque, GE Healthcare, Co. Cork, Ireland). Cardiac CT images were reconstructed with 70% ASIR. The quantitative CT image quality was assessed by image noise in adipose tissue and contrast-to-noise ratio (CNR) in the aorta. The qualitative image analysis was performed on a five-point grading scale by two independent reviewers and interobserver variability was calculated. The results of 32 CT examinations were also compared with the available surgical results for diagnostic accuracy evaluation. Results The effective dose was 0.55±0.10 mSv for the patient population. The iodine load was 3.95±0.73 g iodine. Image noise in adipose tissue was 16.24±1.42 HU and CNR in aorta was 21.90±7.10. All images were acceptable for diagnosis with an average score of 4.52±0.38 and good agreement between reviewers (kappa=0.75). Compared to the surgery results in 32 cases, CT was 97% and 88% accurate diagnosing extracardiac and intracardiac defects, respectively. Conclusion Prospective ECG-triggered cardiac CT using 80 kVp, low-concentration iodinated contrast agent (270 mg iodine/ml) and 70% ASIR reconstruction provides excellent image quality and accurate diagnosis for complex congenital heart disease in infants with reduced contrast medium dose and low radiation dose.

Objectives To evaluate the radiation dose and image quality of cerebral CT angiography (CTA) at 70kVp with 30mL iodinated contrast agent. Methods One hundred patients were prospectively classified into two groups: Group A (n=50), 120kVp cerebral CTA with 60mL iodinated contrast agent reconstructed by filtered back projection (FBP) and Group B (n=50), 70kVp with 30mL iodinated contrast agent reconstructed by sinogram-affirmed iterative reconstruction (SAFIRE). CT values, noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the internal carotid artery (ICA) and middle cerebral artery (MCA) were measured. Subjective image quality was evaluated. Effective dose (ED) was calculated. Results The mean CT values of the ICA and MCA of Group B were higher than those of Group A (all P 0.001). The mean noise of Group A was lower than that of Group B ( P 0.001). SNR ICA , SNR MCA and CNR ICA , CNR MCA of Group A were higher than Group B (all P 0.001). There was no difference in vessel sharpness, noise, and overall quality between the two groups (all P >0.05). ED of Group B (0.2±0.0mSv) was lower than Group A (1.3±0.1 mSv) (p Conclusion Cerebral CTA with iterative reconstruction at 70kVp and 30mL iodinated contrast agent is feasible, allowing for substantial dose reduction compared with conventional cerebral CTA protocol.

Sentinel lymph node mapping can help to direct surgical oncologic staging and metastatic disease detection in patients with complex lymphatic pathways. We hypothesized that indirect computed tomographic lymphography (ICTL) with a water-soluble iodinated contrast agent would successfully map lymphatic pathways of the iliosacral lymphatic center in dogs with anal sac gland carcinoma, providing a potential preoperative method for iliosacral sentinel lymph node identification in dogs. Thirteen adult dogs diagnosed with anal sac gland carcinoma were enrolled in this prospective, pilot study, and ICTL was performed via peritumoral contrast injection with serial caudal abdominal computed tomography scans for iliosacral sentinel lymph node identification. Technical and descriptive details for ICTL were recorded, including patient positioning, total contrast injection volume, timing of contrast visualization, and sentinel lymph nodes and lymphatic pathways identified. Indirect CT lymphography identified lymphatic pathways and sentinel lymph nodes in 12/13 cases (92%). Identified sentinel lymph nodes were ipsilateral to the anal sac gland carcinoma in 8/12 and contralateral to the anal sac gland carcinoma in 4/12 cases. Sacral, internal iliac, and medial iliac lymph nodes were identified as sentinel lymph nodes, and patterns were widely variable. Patient positioning and timing of imaging may impact successful sentinel lymph node identification. Positioning in supported sternal recumbency is recommended. Results indicate that ICTL may be a feasible technique for sentinel lymph node identification in dogs with anal sac gland carcinoma and offer preliminary data to drive further investigation of iliosacral lymphatic metastatic patterns using ICTL and sentinel lymph node biopsy.

Purpose Contrast-enhanced imaging of the breast is frequently used in breast MRI and has recently become more common in mammography. The purpose of this study was to make single-scan contrast-enhanced imaging feasible for photon-counting breast CT (pcBCT) and to assess the spectral performance of a pcBCT scanner by evaluating iodine maps and virtual non-contrast (VNC) images. Methods We optimized the settings of a pcBCT to maximize the signal-to-noise ratio between iodinated contrast agent and breast tissue. Therefore, an electronic energy threshold dividing the x-ray spectrum used into two energy bins was swept from 23.17 keV to 50.65 keV. Validation measurements were performed by placing syringes with contrast agent (2.5 mg/ml to 40 mg/ml) in phantoms with 7.5 cm and 12 cm in diameter. Images were acquired at different tube currents and reconstructed with 300 μm isotropic voxel size. Iodine maps and VNC images were generated using image-based material decomposition. Iodine concentrations and CT values were measured for each syringe and compared to the known concentrations and reference CT values. Results Maximal signal-to-noise ratios were found at a threshold position of 32.59 keV. Accurate iodine quantification (average root mean square error of 0.56 mg/ml) was possible down to a concentration of 2.5 mg/ml for all tube currents investigated. The enhancement has been sufficiently removed in the VNC images, so they can be interpreted as unenhanced CT images. Only minor changes of CT values compared to a conventional CT scan were observed. Noise was increased by the decomposition by a factor of 2.62 and 4.87 (7.5 cm and 12 cm phantoms) but did not compromise the accuracy of the iodine quantification. Conclusions Accurate iodine quantification and generation of VNC images can be achieved using contrast-enhanced pcBCT from a single CT scan in the absence of temporal or spatial misalignment. Using iodine maps and VNC images, pcBCT has the potential to reduce dose, shorten examination and reading time, and to increase cancer detection rates.

Perforator flap-based breast reconstruction in a post mastectomy patient requires dissection of the artery-vein bundle (perforators) responsible for perfusion of the subcutaneous fat and skin of the flap. Traditionally, these reconstructions were performed with the transverse rectus abdominis myocutaneous (TRAM) flap, but autologous breast reconstruction using muscle sparing free flaps has become steadily more popular in recent years. Preoperative imaging to locate and evaluate candidate perforators has become an essential step before patients undergo the microsurgical procedure. Preoperative mapping assists with operative planning, reduces operating times, and brings anatomical variations to their attention. Pre-operative imaging also assists in choosing the appropriate donor site for harvesting flaps. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have been widely used for this type of preoperative imaging. Both MRA and CTA have their inherent advantages and disadvantages, and the preferred modality for this purpose varies by institution based on factors such as scanner availability, radiologist and surgeon experience, and comfort in interpreting the images. Concerns over excessive exposure to ionizing radiation and poor iodinated contrast agent enhancement of the intramuscular perforator course has made MRA the first-choice imaging modality in many centers. The purpose of the article is to review technique and protocols for the pre-operative CTA/MRA in patients who are being considered for a deep inferior epigastric artery perforator (DIEP) or profunda artery perforator (PAP) flap and to familiarize the reader with the normal and variant anatomic features of the deep inferior epigastric and PAP vessels along with the anatomic and surgical considerations used in the selection of perforator flap donor site for breast reconstruction post mastectomy.

Computed tomography can provide high-resolution details on nasal anatomy being potentially useful for the assessment of nasal spray deposition. The purpose of this technical note was to present a method based on CT imaging to assess qualitatively and quantitatively the in vitro spray deposition patterns within the sinonasal cavities of a nasal replica obtained by three-dimensional (3D) printing, using iodinated contrast agent labelled solutions with high spatial and temporal resolution. Using a third generation dual-source CT scanner in single energy mode, scans of a nasal replica were acquired following application of iodinated contrast agent labelled aerosols with an iodine concentration of 92.5 mgl/mL. Two software programmes were then utilised (Osirix MD v.9.0, Pixmeo, Geneva, Switzerland; 3mensio, Pie Medical Imaging, Bilthoven, Netherlands) to generate three-dimensional reconstructions of the scans, thus enabling the rapid detection and visualisation of administered single droplets and their voxel-by-voxel localisation. Using this approach, we achieved recovery rates between 84–98% and 89–109% (depending on the software programme) of the total applied aerosol volume.

Author(s): Ueha, Rumi; Nativ-Zeltzer, Nogah; Sato, Taku; Goto, Takao; Nito, Takaharu; Tsunoda, Koichi; Belafsky, Peter C; Yamasoba, Tatsuya | Abstract: ObjectivesContrast agents (CAs) are essential for upper gastrointestinal and videofluoroscopic swallow studies (VFSSs). Recently, we reported that small amounts of Ba aspiration caused severe acute lung inflammation in a rodent model. However, the underlying molecular biological mechanisms of chronic response to CA aspiration remain unclear. The aims of this study were to explore the underlying molecular biological mechanisms of the chronic response to three kinds of CA aspiration on the lung.Study designAnimal model.MethodsEight-week-old male Sprague Dawley rats were divided into five groups (n = 6, each group). Three groups underwent tracheal instillation of one of three CAs: barium sulfate (Ba), ionic iodinated contrast agent (ICA), and nonionic iodinated contrast agent (NICA). A sham group was instilled with air and a control group was instilled with saline. All animals were euthanized 30 days after treatment and histological and gene analyses were performed.ResultsNo animal died after CA or sham/control aspiration. Ba particles remained after 30 days and caused histopathologic changes and inflammatory cell infiltration. Iodinated ICA and NICA did not result in perceptible histologic change. Expression of Tnf, an inflammatory cytokine was increased in only Ba aspirated rats (P = .0076). Other inflammatory cytokines and fibrosis-related genes did not alter between groups.ConclusionAspirated Ba particles did not clear from the lung within a month and caused mild chronic pulmonary inflammation. ICA and NICA did not cause any inflammatory responses in the lungs, suggesting that ICA and NICA may be safer CAs for VFSS than Ba.Level of evidenceNA.

Background The number of hypersensitivity reactions associated with iodinated contrast media (ICM) is increasing with widespread use of radiographic contrast agents. These hypersensitivity reactions are unpredictable and sometimes lead to severe reactions such as anaphylaxis. Objective To investigate the value of intradermal skin test (IDT) as a clinical screening tool for prediction of a hypersensitivity reaction to ICM. Methods We performed IDT in the patients scheduled to receive an iodinated contrast agent between September 2015 and April 2017. After IDT, the contrast agent tested was administered intravenously, regardless of the results of skin testing, and the patients were carefully monitored. Results We recruited 2,918 patients in 2 hospitals, and 2,843 were included in the final analysis. Fifteen (0.5%) of the 2843 patients had a positive IDT result before scheduled computed tomography scan; however, none of these patients experienced a hypersensitivity reaction after the administration of a full dose of ICM. Meanwhile, 19 patients who experienced hypersensitivity reactions after ICM challenge had showed a negative IDT result. The sensitivity and the positive predictive value of IDT for ICM were both 0%. Conclusions Routine IDT before the administration of an iodinated contrast agent does not predict hypersensitivity considering its extremely low sensitivity and a low positive predictive value.

Understanding hip osteoarthritis requires new investigational tools for quantitative studies of biophysical and biomechanical properties as well as for determination of structure. Three new protocols to study pathological changes in cartilage and to measure cartilage thickness in intact human hips are described using synchrotron contrast enhanced computed tomography (sCECT) with the iodinated contrast agent CA4+. Ten human cadaver hips were prepared and injected with CA4+ using three different methods, all of which included rotation and distraction of the joint. CA4+ diffusion into cartilage was monitored using sCECT. The thickness of acetabular and femoral cartilage was also measured. Diffusion times ranged from 2 h to 75 h, depending on the injection protocol and the cartilage region. Direct single injection of the contrast through the labrum resulted in the fastest diffusion times. The iodine attenuation coefficient, which reflects the contrast agent distribution in the cartilage, ranged from 0.0142/cm to 0.1457/cm. Three injections at the head/neck conjunction area yielded the highest iodine attenuation coefficients in cartilage. The femoral cartilage in the Superior-Medial compartment was significantly thicker than in the other 3 femoral compartments, and femoral cartilage in the Superior-Anterior compartment was significantly thinner than the other 3 femoral compartments. The acetabular cartilage in the Superior compartment was significantly thicker than that in the Superior-Posterior compartment. sCECT with CA4+ allows assessment of hip cartilage thickness with 0.1 mm isotropic voxel size, sufficient for evaluating cartilage pathology and biomechanics.

Iohexol is a commonly used second generation non-ionic iodinated contrast agent with a multitude of advantages such as low osmolarity and competent intravenous countenance having minimum adverse reactions. Our study anticipated to improve the efficacy of Iohexol as a contrast enhancing agent for Computed Tomography, by envisaging bio-compatible albumin based Iohexol nanoparticles. This nanoparticulate system was developed primarily to enhance the anatomic imaging while increasing its residence time in the blood pool. Towards this goal, we developed Iohexol albumin nanoparticles using glutaraldehyde as a cross linking agent, and Polyethylene glyocol Iohexol albumin nanoparticles by physical adsorption to ameliorate its circulation time. These formulations were studied in comparison to the clinically available Iopamidol™. Both Iohexol albumin nanoparticles and Polyethylene glyocol Iohexol albumin nanoparticles were characterized for its size, physicochemical properties and entrapment efficiency. Iohexol albumin nanoparticles showed a size range of 254±5 nm and post surface modification the size of Polyethylene glyocol Iohexol albumin nanoparticles was found to be 283±7 nm in diameter, with and entrapment efficiency Iohexol as of 85%. Further, In vivo computed tomography imaging in New Zealand white rabbits for the developed formulations manifested an enhancement in the anatomical structures of heart, liver and kidneys along with an increased residence time in the blood pool of 3 h in contrast to Iopamidol™. Our study interprets that Polyethylene glyocol Iohexol albumin nanoparticles have prolonged residence time producing much greater conspicuity of anatomic features and warrants further detail study of the formulation in disease models.

Purpose This study assesses the clinical value of dual-energy computed tomography (DECT) in the early diagnosis of intracranial hemorrhage and evaluates the risk of hemorrhagic transformation in patients with acute ischemic stroke (AIS) after mechanical thrombectomy. Methods Patients with AIS who have undergone thrombectomy with Solitaire stent and DECT within one hour after surgery were prospectively enrolled. Linear mixed energy images, virtual non-contrast (VNC) image, and iodine overlay map (IOM) were obtained. Routine CT scan was performed 24 h postoperatively. The sensitivity, specificity, positive and negative predictive values, and accuracy of DECT in the early diagnosis of intracranial hemorrhage was evaluated. The iodine concentration of intracranial lesions was measured by IOM with the follow-up results taken as reference. Receiver operating characteristic (ROC) analysis was performed to obtain the threshold of hemorrhagic transformation and increased bleeding. Results Among the 44 patients enrolled in this study, 25 (56.8 %) were diagnosed with simple extravasation of iodinated contrast agent, and 19 (43.2 %) showed intracranial hemorrhage in DECT. Compared with the follow-up CT 24 h after surgery, early diagnosis of postoperative intracranial hemorrhage using DECT demonstrated a sensitivity of 90.5 %, specificity of 100 %, positive predictive rate of 100 %, negative predictive rate of 92.0 %, and accuracy of 95.5 %. Among the 86 intracranial lesions that underwent iodine concentration measurement, 19 were diagnosed with hemorrhagic transformation or increased bleeding, and 67 were diagnosed without the aforementioned conditions. The sensitivity and specificity for differentiating the two groups were 73.7 % and 92.5 %, respectively, with a cut-off value of 2.7 mg/mL. Conclusion DECT is clinically valuable in early diagnosis and prediction of intracranial hemorrhage after mechanical thrombectomy in AIS patients.

Objectives: The aim of this study was to assess scanning activities at Yopougon University Hospital through its most common application that is the cranio-encephalic CT in order to make proposals for the improvement of its use. Patients and Methods: This was a three-year-cross-sectional study based on cranio-encephalic CT scans performed at Yopougon University Hospital from January 2011 to December 2013. All CT scans were performed on a TOSHIBA 64-bar scanner with or without injection of iodinated contrast agent. The variables studied were the epidemiological-clinical elements (age, gender and indications), the exploration technique, the overall results and the various pathologies discovered. Results: The mean age of our patients was 35.4 years with a predominance of children (age group of 0 and 14 years). The sex ratio was 1.38. Motor deficits (19.3%) and head trauma (17.5%) was the main indication of cranio-encephalic scanners. We performed 221 examinations without injection of iodinated contrast agent (36.8%) and 379 examinations with injection of iodinated contrast agent (63.2%). We recorded 298 normal findings and 302 pathological findings that are 49.7% and 50.3% respectively. Strokes were the predominant pathology found on the cranio-encephalic scanners (43.7%) followed by traumatic pathology (20.9%). Conclusion: The rate of normal findings for cranio-encephalic scanners was very high (49.7%). Pathological findings were dominated by strokes (43.7%) and traumatic pathology (20.9%). Infectious pathology was paradoxically rare (3%). A more rigorous prescription of cranio-encephalic scanners based on a well-conducted clinical examination and the guides of good use of imaging examinations (guidelines) could help to reduce the rate of normal scanner at Yopougon University Hospital.

INTRODUCTION: Computed tomography perfusion (CTP) is increasingly employed in the diagnosis and management of ischaemic stroke but radiation dose can be significant and optimising contrast-to-noise ratio (CNR) is challenging. This study aimed to quantify and optimise the balance between CNR as a surrogate for image quality and radiation dose. METHODS: A perspex head phantom with vials of dilute contrast agent was scanned using a Siemens Definition Flash 128-slice scanner. The CTP protocol exposure parameters were adjusted over 70-120 kVp and 150-285 mAs. Measurements were obtained for the average dose per slice, Hounsfield Units (HU) for iodinated contrast agent, and the image noise for background regions of perspex. The CNR was measured as a function of the volumetric CT dose index (CTDIvol) and kVp. RESULTS: A change from 120 to 80 kVp, achieved the same CNR with 60% reduction in dose. Alternatively, for the same dose, the change from 120 to 80 kVp improved CNR by +58%. A change from 80 to 70 kVp while operating at the same CNR, led to 13% reduction in dose. Alternatively, maintaining the same dose while changing from 80 to 70 kVp improved the CNR by +7%. CONCLUSION: Lower beam energies achieved the same CNR with less dose, or improved CNR at the same dose. A reduction from 80 kVp to 70 kVp may be clinically useful to optimise CTP acquisitions.

BACKGROUND Contrast enhanced spectral mammography (CESM) is a new method of breast cancer diagnosis in which an iodinated contrast agent is injected and dual-energy mammography is obtained in multiple views of the breasts. The aim of this study was to compare the degree of enhancement on CESM with lesion characteristics on mammography (MG) and lesion histology in women with suspicious breast lesions. MATERIAL AND METHODS The degree of enhancement on CESM (absent, weak, medium, or strong) was compared to lesion characteristics on MG (mass, mass with microcalcifications, or microcalcifications alone) and histology (infiltrating carcinoma, intraductal carcinoma, or benign) to compare sensitivity of the two modalities and to establish correlations that might improve diagnostic accuracy. RESULTS Among 225 lesions identified with CESM and MG, histological evaluation revealed 143 carcinomas (127 infiltrating, 16 intraductal) and 82 benign lesions. This is the largest cohort investigated with CESM to date. The sensitivity of CESM was higher than that of MG (100% and 90%, respectively, p=0.010). Medium or strong enhancement on CESM and the presence of a mass on MG was the most likely indictor of malignancy (55.1% p=0.002). Among benign lesions, 60% presented as enhancement on CESM (were false-positive), and most frequently as medium or weak enhancement, together with a mass on MG (53%, p=0.047). Unfortunately, the study did not find combinations of MG findings and CESM enhancement patterns that would be helpful in defining false-positive lesions. We observed systematic overestimation of maximum lesion diameter on CESM compared to histology (mean difference: 2.29 mm). CONCLUSIONS Strong or medium enhancement on CESM and mass or mass with microcalcifications on MG were strong indicators of malignant transformation. However, we found no combination of MG and CESM characteristics helpful in defining false-positive lesions.

Objective To evaluate a population of dogs for evidence of contrast-induced nephropathy (CIN). Design A retrospective case review between 2006 and 2012. Setting A university teaching hospital. Animals A total of 1,217 client-owned dogs that were administered intravenous iodinated contrast agents were reviewed for evidence of CIN. Inclusion required a measured serum creatinine within 1 week prior as well as within 1 week following administration of contrast. Eighty-six dogs with 92 contrast administrations qualified for inclusion. Interventions None. Measurements and Main Results CIN was defined as an increase in >44.2 μmol/L (0.5 mg/dL) from baseline creatinine concentration within 1 week following administration of an intravenous iodinated contrast agent. A total of 7.6% of contrast administrations (7/92) fulfilled the definition of CIN. The creatinine postcontrast administration as well as the change in creatinine concentration was significantly higher in the CIN group than in the non-CIN group (median postcreatinine 150 μmol/L [1.7 mg/dL] versus 70.7 μmol/L [0.8 mg/dL], median change in creatinine 53 μmol/L [0.6 mg/dL] versus 0 μmol/L). Patient signalment, initial creatinine, number of total contrast administrations, dose of contrast received, duration of anesthesia, IV fluid administration, administration of nephrotoxic agents, and use or vasopressor therapy were not significantly different between groups. Conclusions The temporal association between contrast administration and renal injury in these cases highlights the potential for CIN in dogs. Due to the retrospective nature of this study, a causal association between contrast administration and renal injury cannot be determined. A prospective study is needed to further evaluate CIN in dogs.

BACKGROUND AND PURPOSE Contrast-induced acute kidney injury (CI-AKI) is a serious complication of the use of iodinated contrast agents. This problem is particularly acute in interventional neurology and interventional cardiology, probably due to the intra-arterial route of injection, high contrast volumes, and preexisting risk factors of these patients. In an attempt to develop a contrast agent that is less damaging to the kidneys, we have studied the effects of adding a small amount of the substituted cyclodextrin, sulfobutyl-ether-β-cyclodextrin (SBECD), to iohexol in rodent models of renal toxicity. METHODS Renally compromised mice and rats were injected with iohexol and iohexol-SBECD via the tail vein. The renal pathology, creatinine clearance, and survival benefits of iohexol-SBECD were studied. The safety of direct intra-arterial injection of the iohexol-SBECD formulation was studied in a dog heart model system. Mechanism of action studies in cell culture model using a human kidney cell line was performed using flow cytometry. RESULTS Nephrotoxicity was significantly reduced using iohexol-SBECD compared to iohexol alone, at mole ratios of iohexol:SBECD of 1:0.025. SBECD increased survival from 50% to 88% in a rat survival study. In the dog heart model, iohexol-SBECD was safe. Cell culture studies suggest that SBECD interferes with the early stages of contrast-induced apoptosis in a human renal cell line. CONCLUSION We have shown that the addition of a small amount of SBECD (one molecule of SBECD per 40 iohexol molecules) significantly protects rodent kidneys from CI-AKI. Further development of this new formulation of iodinated contrast is warranted.

In recent years, coronary computed tomography angiography has become an increasingly safe and noninvasive modality for the evaluation of the anatomical structure of the coronary artery tree with diagnostic benefits especially in patients with a low-to-intermediate pretest probability of disease. Currently, increasing evidence from large randomized diagnostic trials is accumulating on the diagnostic impact of computed tomography angiography for the management of patients with acute and stable chest pain syndrome. At the same time, technical advances have substantially reduced adverse effects and limiting factors, such as radiation exposure, the amount of iodinated contrast agent, and scanning time, rendering the technique appropriate for broader clinical applications. In this work, we review the latest developments in computed tomography technology and describe the scientific evidence on the use of cardiac computed tomography angiography to evaluate patients with acute and stable chest pain syndrome.

2D digital subtraction angiography (DSA) has become an important technique for interventional neuroradiology tasks, such as detection and subsequent treatment of aneurysms. In order to provide high-quality DSA images, usually undiluted contrast agent and a high X-ray dose are used. The iodinated contrast agent puts a burden on the patients’ kidneys while the use of high-dose X-rays expose both patients and medical staff to a considerable amount of radiation. Unfortunately, reducing either the X-ray dose or the contrast agent concentration usually results in a sacrifice of image quality. To denoise a frame, the proposed spatiotemporal denoising method utilizes the low-rank nature of a spatially aligned temporal sequence where variation is introduced by the flow of contrast agent through a vessel tree of interest. That is, a constrained weighted rank-1 approximation of the stack comprising the frame to be denoised and its temporal neighbors is computed where the weights are used to prevent the contribution of non-similar pixels toward the low-rank approximation. The method has been evaluated using a vascular flow phantom emulating cranial arteries into which contrast agent can be manually injected (Vascular Simulations Replicator, Vascular Simulations, Stony Brook NY, USA). For the evaluation, image sequences acquired at different dose levels as well as different contrast agent concentrations have been used. Qualitative and quantitative analyses have shown that with the proposed approach, the dose and the concentration of the contrast agent could both be reduced by about 75%, while maintaining the required image quality. Most importantly, it has been observed that the DSA images obtained using the proposed method have the closest resemblance to typical DSA images, i.e., they preserve the typical image characteristics best. Using the proposed denoising approach, it is possible to improve the image quality of low-dose DSA images. This improvement could enable both a reduction in contrast agent and radiation dose when acquiring DSA images, thereby benefiting patients as well as clinicians. Since the resulting images are free from artifacts and as the inherent characteristics of the images are also preserved, the proposed method seems to be well suited for clinical images as well.