Low-osmolar Contrast Agents Research Articles

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.

Differential Incidence of Contrast-Associated Acute Kidney Injury: Comparing Intravenous and Intraarterial Contrast Administration.

Contrast-associated acute kidney injury (CA-AKI) remains a significant concern in diagnostic and invasive procedures, particularly in the context of iodinated contrast material administration. The traditional definition of CA-AKI, based on serum creatinine elevation following contrast exposure, may not accurately capture its multifactorial nature. Studies have provided new insights into the differential incidence of CA-AKI between intravenous and intraarterial contrast administration, emphasizing the importance of tailored preventative strategies for high-risk procedures. This higher risk may arise from two proposed mechanisms: one implicating free radical formation leading to cytotoxicity and apoptosis in renal cells and another suggesting that contrast media alter renal hemodynamics, particularly in the outer medulla, by constricting the vasa recta and reducing medullary flow. Advances in technology and patient care, including contemporary use of low-osmolar contrast agents and hydration protocols, mitigate CA-AKI risk. Diagnostic and invasive procedures should not be avoided solely due to concerns about renal dysfunction if the patient is likely to benefit clinically.

Iso-osmolar vs low-osmolar contrast agents for coronary optical coherence tomography: a blinded prospective randomized controlled study.

The impact of contrast type on coronary optical coherence tomography (OCT) imaging has received limited research. We conducted a blinded, prospective, single-center, randomized, controlled crossover study comparing iso-osmolar contrast media (IOCM) with low-osmolar contrast media (LOCM) in patients undergoing clinically indicated coronary OCT imaging. Patients were randomly assigned to undergo OCT imaging with either IOCM or LOCM as the initial contrast medium. Following a washout period, a second run of OCT imaging of the same coronary vessel was performed using the other contrast medium. A total of 62 patients were randomized to IOCM first (n = 31) or LOCM first (n = 31). Mean patient age was 65.9 ± 11.2 years and 74.2% were male, with high prevalence of dyslipidemia (82.3%) and prior myocardial infarction (41.9%). Percutaneous coronary intervention was performed in 60 cases (96.8%) and the left anterior descending artery was the most common target vessel (53.3%). The contrast volume used for OCT imaging was similar for IOCM and LOCM (8.0 [6.9, 9.0] mL vs 8.0 [6.7, 9.0] mL; P = .89), as was the length of clear OCT images (70.0 [62.8, 74.0] mm for IOCM vs 70.0 [64.0, 74.0] mm for LOCM; P = .65). Electrocardiographic changes were observed in 11 runs with IOCM (ventricular repolarization changes in 9 runs and premature ventricular contractions [PVCs] in 2 runs) vs 12 runs with LOCM (ventricular repolarization changes in 9 runs and PVCs in 3 runs). The use of IOCM in coronary OCT is associated with similar contrast volume and clear imaging length when compared with LOCM.

Advancements in preventing post-contrast acute kidney injury in EVAR: clinical strategies and future directions.

Abdominal Aortic Aneurysm (AAA) represents a signif i cant global health issue with a high risk of rupture, resulting in substantial mortality rates. Endovascular Aneurysm Repair (EVAR) has emerged as the preferred treatment method due to its minimally invasive nature. However, the procedure carries a risk of acute kidney injury (AKI), particularly post-contrast acute kidney injury (PC-AKI), which can adversely af f ect patient outcomes. This review examines the incidence, pathophysiology, and prevention strategies for PC-AKI in the context of EVAR. It synthesizes current research on the mechanisms underlying PC-AKI, such as renal vasoconstriction, oxidative stress, and tubular toxicity. The ef f ectiveness of various preventive measures, including pre-procedural hydration, use of low-osmolality contrast agents, and alternative imaging techniques, is evaluated. Additionally, the review explores patient-specif i c risk factors and the potential of novel pharmacologic interventions. The incidence of PC-AKI in EVAR varies based on procedural complexity and patient-specif i c factors like preexisting renal insuf f i ciency, diabetes, and hypertension. Preventive strategies such as intravenous hydration and the use of less nephrotoxic contrast agents have shown ef f ectiveness. Advances in imaging technology and innovative pharmacologic interventions, including antioxidants and vasodilatory drugs, present promising approaches to reducing the risk of PC-AKI. Ef f ective management of PC-AKI in EVAR necessitates a comprehensive and multifaceted approach that considers both procedural and patient-specif i c factors. Future research should aim to standardize diagnostic criteria, ref i ne preventive strategies, and explore novel therapies. Enhanced understanding of PC-AKI pathophysiology and personalized preventive measures can improve patient safety and outcomes in EVAR procedures.

Impact of a reduced iodine load with deep learning reconstruction on abdominal MDCT.

To evaluate the impact of a reduced iodine load using deep learning reconstruction (DLR) on the hepatic parenchyma compared to conventional iterative reconstruction (hybrid IR) and its consequence on the radiation dose and image quality. This retrospective monocentric intraindividual comparison study included 66 patients explored at the portal phase using different multidetector computed tomography parameters: Group A, hybrid IR algorithm (hybrid IR) and a nonionic low-osmolality contrast agent (350 mgI/mL); Group B, DLR algorithm (DLR) and a nonionic iso-osmolality contrast agent (270 mgI/mL). We recorded the attenuation of the liver parenchyma, image quality, and radiation dose parameters. The mean hounsfield units (HU) value of the liver parenchyma was significantly lower in group B, at 105.9 ± 10.9 HU versus 118.5 ± 14.6 HU in group A. However, the 90%IC of mean liver attenuation in the group B (DLR) was between 100.8 HU and 109.3 HU. The signal-to-noise ratio of the liver parenchyma was significantly higher on DLR images, increasing by 56%. However, for both the contrast-to-noise ratio (CNR) and CNR liver/PV no statistical difference was found, even if the CNR liver/PV ratio was slightly higher for group A. The mean dose-length product and computed tomography dose index volume values were significantly lower with DLR, corresponding to a radiation dose reduction of 36% for the DLR. Using a DLR algorithm for abdominal multidetector computed tomography with a low iodine load can provide sufficient enhancement of the liver parenchyma up to 100 HU in addition to the advantages of a higher image quality, a better signal-to-noise ratio and a lower radiation dose.

Comparative Analysis of Rapid vs Standard Premedication Protocols for Contrast Allergy

Contrast reaction rates have been poorly studied with nonionic low osmolar agents. Premedication protocols to prevent contrast reactions to ionic high osmolar contrast have been studied in the past; however, protocol outcomes for the currently used nonionic low osmolar contrast is less clear. The purpose of this study was to evaluate the rate of contrast reactions with nonionic low osmolar using the standard premedication protocol as well as the effect of using a rapid premedication protocol. Retrospective single institution review of computed tomography (CT) scans from May 2011 through January 2022 was performed by searching the Cerner Soarian medical records system for patients with documented contrast allergies who received contrasted CT scans. The patients were then divided into groups depending on whether they received the 13-hour premedication protocol vs the 4-hour rapid protocol. Contrast reaction was extrapolated from administration of prednisone, hydrocortisone, diphenhydramine, or epinephrine outside of protocol within one hour with corresponding indication in the ordering system. Basic statistical analysis including χ2 testing was performed on acquired data. We performed 2588 premedicated contrasted CT cans during the study period, 2102 (81.2%) of which underwent the 13-hour premedication protocol and 486 (18.7%) underwent 4-hour premedication protocol. The average age of the 13-hour group was 62 years (range, 11-92) years and 1345 (64%) were female and the 4-hour protocol had an average age of 61 years (range, 5-92 years) and 277 (57%) were female. In the 13-hour group, there was an overall contrast reaction rate of 29% (613): 124 patients received prednisone, 107 hydrocortisone, 388 diphenhydramine, and 3 epinephrine. In the 4-hour group, 44% (214) patients had a contrast reaction: 78 received prednisone, 89 hydrocortisone, 41 diphenhydramine, and 6 epinephrine. There was significantly more treatment for contrast reaction in the 4-hour protocol group (P < .01). Protocols for premedication to prevent contrast allergy reactions have been based on ionic high osmolar contrast usage and have not been separately validated for use with nonionic low osmolar contrast agents. This study demonstrates that the preexisting protocols appear only partially effective in preventing contrast reactions and the outcomes for the rapid 4-hour protocol performed significantly worse than the standard protocol. These outcomes show the need for further study and protocol refinement as well as continued vigilance for contrast reactions while using the current protocols.

Interventions for Promoting Meconium Passage in Very Preterm Infants-A Survey of Current Practice at Tertiary Neonatal Centers in Germany.

Meconium passage is often delayed in preterm infants. Faster meconium passage appears to shorten the time to full enteral feeds, while severely delayed meconium passage may indicate meconium obstruction. Neonatologists often intervene to promote meconium passage, assuming that benefits outweigh potential risks such as necrotizing enterocolitis (NEC). We performed an anonymous online survey on different approaches to facilitate meconium passage among tertiary neonatal intensive care units (NICUs) in Germany between February 2022 and April 2022. We collected information on enteral nutrition, gastrointestinal complications, and interventions to promote meconium passage. We received 102 completed questionnaires (response rate 64.6%). All responders used interventions to promote meconium passage, including enemas (92.0%), orally applied contrast agents (61.8%), polyethylene glycol (PEG) (46.1%), acetylcysteine (19.6%), glycerin suppositories (11.0%), and maltodextrin (8.8%). There was substantial heterogeneity among NICUs regarding frequency, composition, and mode of administration. We found no differences in NEC incidence between users and nonusers of glycerin enemas, high or low osmolar contrast agents, or PEG. There is wide variability in interventions used to promote meconium passage in German NICUs, with little or no evidence for their efficacy and safety. Within this study design, we could not identify an increased risk of NEC with any intervention reported.

The potential effect of iopamidol contrast on renal function in patients infected with SARS-CoV-2 virus: A retrospective cohort study.

Many types of computed tomography (CT) scans require the use of contrast. Acute kidney injury (AKI) is a known adverse effect of intravenous contrast administration. To our knowledge, the effects of low-osmolar contrast agents such as iopamidol on renal function in patients infected with the SARS-CoV-2 virus have never been studied. This study investigates the incidence of AKI following iopamidol contrast administration in patients infected with the SARS-CoV-2 virus. This retrospective cohort study included two groups: patients who received CT pulmonary angiography who were infected with SARS-CoV-2 virus and those who tested negative for SARS-CoV-2. Data were collected from the electronic medical record of a single hospital from January 1, 2020, to September 15, 2020. AKI was defined using the Kidney Disease: Improving Global Outcomes definition: increase in serum creatinine by ≥0.3 mg/dL (≥26.5 mcmol/L) within 48 h, or increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days, or urine volume <0.5 mL/kg/h for 6 h. AKI occurred in 13.51% of patients in the SARS-CoV-2 positive group and 16.92% of patients in the negative group. Using a two-sample test to compare the equality of proportions (with continuity correction factor), we found there is no significant difference in the two proportions (P = 0.3735). There was no significant difference in the incidence of AKI between SARS-CoV-2 positive and negative groups. Given the limitations of this study, further work must be done on this topic.

Computer tomography in diagnostics and treatment of inflammatory complications of diverticular disease of the colon

AIM: to evaluate the role of computed tomography (CT) in the treatment and diagnostic algorithm in patients with complicated diverticular disease (CDD).PATIENTS AND METHODS: during the period from 2014 to 2020, 165 hospitalized patients with complications of CDD included in the study. Fifteen (9.1%) patients were hospitalized for elective indications and 150 (90.9%) as emergencies. The indications for hospitalization were inflammatory complications of CDD. Computed tomography with intravenous contrast was performed in 89 (53.9%) patients. The study was performed on a 64-slice CT “Philips Brilliance 64” with intravenous bolus injection of a low-osmolar iodine-containing contrast agent. The absence of the CT in the remaining patients is due to the presence of classical symptoms of acute diverticulitis with a previously verified diagnosis of CDD, the presence of an informative transabdominal ultrasound, as well as the refusal of patients from CT.RESULTS: the CT allowed to verify the presence of diverticula in the patients, to reveal the distinctive CT signs and pathognomonic symptoms of inflammatory complications of CDD, as well as to establish the severity of the complications that occurred. The specific signs of the destruction of the diverticulum and the complications developed were abdominal mass, abscess, peritonitis, and fistula. Besides the diagnostic value, CT scan permitted to choose the treatment approach and to clarify indications for surgery. Besides that, some CDD complications revealed by CT were considered as a predictor of ineffectiveness of conservative treatment, which requires surgery.CONCLUSION: CT is a valuable diagnostic method for CDD which allows to determine timely the clinical form of inflammatory complication, to find out indications for surgery and to predict high risk of recurrence.

Contrast-induced nephropathy after staged balloon pulmonary angioplasty: lower risk compared with left-sided cardiac procedures

Abstract Introduction The risk of contrast-induced nephropathy (CIN) after left-sided cardiac procedures is reported as 10–15%. When the ratio of total contrast volume in ml to glomerular filtration rate (GFR) in mL/min (ratio V/GFR) exceeds 3.7, the risk increases significantly. However, there are few reports regarding the risk of CIN in patients (pts) with right-sided cardiac interventions such as balloon pulmonary angioplasty (BPA) and ratio V/GFR is not validated for use in this procedures. Purpose To assess the prevalence of CIN in pts with chronic thromboembolic pulmonary disease with or without hypertension (CTEPH/CTED) undergoing BPA. Methods Prospective single-centre study that included all BPA sessions performed from 2017 to 2020. Serum creatinine concentration (SC) was measured and the GFR was estimated using the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) before and 48 hours after each BPA procedure and 6 months after BPA treatment completion. CIN was defined as an increase of ≥25% and/or ≥0.5 mg/dL in SC from the baseline value within 48h of contrast administration. Results 76 consecutive BPA sessions were performed in 15 CTEPH/CTED pts: mean age 63.2±14.0 years, 60% female, 86.7% CTEPH, mean of 5.3±1.9 sessions per patient with 4.3±1.9 vessels dilated per session. Mean value of GFR before BPA program was 73.5±26.3 mL/min. All the procedures were performed using low-osmolality contrast agent with a 1:1 dilution ratio with normal saline solution. Pts received 273.0±73.0 mL of contrast per session with a ratio V/GFR 3.7±1.7 mL. SC and GFR did not change significantly within 48h after BPA (+3.1%, p=0.07 and −3.0%, p=0.13, respectively). Ratio V/GFR &amp;gt;3.7 occurred in 44.3% of cases (n=31), but CIN occurred in only 5.3% (n=4) with an increase in SC &amp;lt;0.5 mg/dL but ≥25% in 3 cases (+33% in mean) and ≥0.5 mg/dL in 1 case. None of the pts required renal replacement therapy. Higher SC and lower GFR 48h after BPA were significantly correlated with greater rato V/GFR during procedure (r=0.75, p&amp;lt;0.01 and r=−0.74, p&amp;lt;0.01, respectively) – see figure. But neither higher values of ratio V/GFR (OR 1.43; CI95% 0.84–2.41; p=0.19) nor V/GFR &amp;gt;3.7 (OR 1.28; CI95% 0.17–9.6; p=0.81) were predictors of CIN. GFR before procedure did not influence the contrast volume administered (p=0.901), number of vessels (p=0.63) and segments treated by session (p=0.45). At 6 months follow-up, there was a trend for SC (1.3±0.2 mg/dL vs 1.1±0.2 mg/dL, −15%, p=0.43) and GFR (44.5±8.3 mg/dL vs 53.0±12.6 mg/dL, +16%, p=0.34) improvement in pts with impaired renal function at baseline (GFR&amp;lt;60 mL/min). Conclusions These findings suggested that the occurrence of CIN after BPA was low, raising the hypothesis that the influence of contrast agent on renal function could differ in right-sided cardiac interventions. Although the ratio V/GFR may be correlated with the risk of nephropathy, it is necessary to find a new cut-off to predict CIN in BPA pts. Funding Acknowledgement Type of funding sources: None.

Theoretical B3LYP Study on Electronic Structure of Contrast Agent Iopamidol

Nonionic low-osmolar contrast agents are thought about safe for intravenous or intra-arterial administration. Iopamidol is one of the contrast agents used for diagnostic clinical computed tomography (CT) protocols last four decades years.The molecular structure of Iopamidol was calculated by the B3LYP density functional model with the LANL2DZ basis set by the Gaussian program. The natural bond orbital analysis in terms of the hybridization of atoms and the electronic structure of the title molecule have been analyzed by using the data obtained from the quantum chemical results. First-order hyperpolarizability (ßtot), the dipole moment (µ) and polarizability (α) and anisotropic polarizability (∆α) of the molecule have been reported. HOMO and LUMO energies and parameters related to energies, and dipole moment, polarizability and hyperpolarizability show minor dependences on the solvent polarity. The hardness of Iopamidol decreases with increasing solvent polarity. The stability of the Iopamidol contrast agent with the hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital analysis. In addition, thermodynamic properties were obtained in the range of 200-1000 K.

Effects of high iodine containing low osmolar contrast agent (visipaque) on thyroid function tests

Objective: Investigating high iodine containing low osmolar contrast agent (visipaque) effects on thyroid function tests and thyroid sonography characteristics. Methods: 65 euthyroid cases and 92 controls composed the samples in baseline. Thyroid function tests, Urine Iodine Concentration (UIC) and thyroid sonography were conducted for both groups before and 1 and 3 months after angiography. Serum levels of T4, T3, T3RU, TSH, TPO-Ab and UIC were measured, and hypo/heyperthyroidism prevalence was compared between groups. Results: Mean T3,T4 and TSH changes 1 month after angiography were insignificant in both groups (P:0.61,P:0.4 and P:0.14, P:0.23 in cases and controls for T3 and T4). Medians among cases and controls were 12.8 and 16.75 µg/dl, respectively, at baseline. These values varied to 28.45 and 15.2µg/dl, and 12.95 and 14.2µg/dl 1 month and 3 months after angiography in case and control groups, respectively. UIC increase one month after angiography was significant among cases (P=0.002). TPO-Ab+ were same 3 months after angiography. Thyroid volume changes were significant among cases (P&lt;0.001) and insignificant among controls (P=0.680). No significant difference was seen between cases and controls in overt hypothyroidism, however, a considerable change was seen in thyroid volume and UIC one month after angiography among cases. The hypothyroidism rate among cases was insignificant which may be either related to few cases or short half-life of visipaque (2.1 hour) so that 97% of injected dose was excreted in urine within 24 hours. Conclusion: Thyroid function test is not recommended before angiography in patients without previous thyroid records.

Contrast-enhanced micro-computed tomography of articular cartilage morphology with ioversol and iomeprol.

Non-ionic, low-osmolar contrast agents (CAs) used for computed tomography, such as Optiray (ioversol) and Iomeron (iomeprol), are associated with the reduced risk of adverse reactions and toxicity in comparison with ionic CAs, such as Hexabrix. Hexabrix has previously been used for imaging articular cartilage but has been commercially discontinued. This study aimed to evaluate the efficacy of Optiray and Iomeron as alternatives for visualisation of articular cartilage in small animal joints using contrast-enhanced micro-computed tomography (CECT). For this purpose, mouse femora were immersed in different concentrations (20%-50%) of Optiray 350 or Iomeron 350 for periods of time starting at five minutes. The femoral condyles were scanned ex vivo using CECT, and regions of articular cartilage manually contoured to calculate mean attenuation at each time point and concentration. For both CAs, a 30% CA concentration produced a mean cartilage attenuation optimally distinct from both bone and background signal, whilst 5-min immersion times were sufficient for equilibration of CA absorption. Additionally, plugs of bovine articular cartilage were digested by chondroitinase ABC to produce a spectrum of glycosaminoglycan (GAG) content. These samples were immersed in CA and assessed for any correlation between mean attenuation and GAG content. No significant correlation was found between attenuation and cartilage GAG content for either CAs. In conclusion, Optiray and Iomeron enable high-resolution morphological assessment of articular cartilage in small animals using CECT; however, they are not indicative of GAG content.

Nefropatia induzida por contraste não iônico isosmolar versus iônico de baixa osmolaridade em pacientes após intervenção coronária percutânea

ABSTRACT Background Coronary angiography is an advance in the management of a variety of heart conditions, but iodinated contrast injection can lead to contrast-induced nephropathy, especially in high-risk populations. There is still no consensus on the best type of contrast agent to be used. The objective of this study was to evaluate the occurrence of contrast-induced nephropathy in patients undergoing percutaneous coronary intervention, comparing a low-osmolar contrast agent with an iso-osmolar contrast agent. Methods This was a single center, longitudinal, [...]

Maximum allowable contrast dose and prevention of acute kidney injury following cardiovascular procedures.

Contrast-induced acute kidney injury (CI-AKI) is a serious complication. Although nonmodifiable and modifiable risk factors have been thoroughly characterized, the utility of the maximal allowable contrast dose (MACD) has not received adequate attention. The focus of this review is to provide a critical appraisal of this modifiable risk factor. Several retrospective and prospective cohort studies have demonstrated that the incidence of CI-AKI among patients receiving contrast media in volumes exceeding the MACD is consistently higher compared with those who do not exceed the MACD (an average of 24 vs. 6%). Furthermore, the MACD is independent predictor of CI-AKI and other adverse events. A two-step algorithm incorporating the determination of the MACD and the contrast volume to eGFR ratio prior to a planned cardiovascular procedure is a sound approach to minimize contrast volume and prevent CI-AKI. Prevention of CI-AKI must remain a clinical priority. Intraprocedural preventive measures should include a priori calculation of the MACD and contrast volume to eGFR ratio to limit contrast volume. Other measures may include the adoption of the transradial approach, the use of automated contrast injectors and small catheters to limit contrast volume, the use of low-osmolar contrast agents, and if necessary the use of staged procedures. We call for the system-wide implementation of evidence-based care bundles to prevent CI-AKI.

The Application of Contrast Media for In Vivo Feature Enhancement in X-Ray Computed Tomography of Soil-Grown Plant Roots.

The use of in vivo X-ray microcomputed tomography (μCT) to study plant root systems has become routine, but is often hampered by poor contrast between roots, soil, soil water, and soil organic matter. In clinical radiology, imaging of poorly contrasting regions is frequently aided by the use of radio-opaque contrast media. In this study, we present evidence for the utility of iodinated contrast media (ICM) in the study of plant root systems using μCT. Different dilutions of an ionic and nonionic ICM (Gastrografin 370 and Niopam 300) were perfused into the aerial vasculature of juvenile pea plants via a leaf flap (Pisum sativum). The root systems were imaged via μCT, and a variety of image-processing approaches used to quantify and compare the magnitude of the contrast enhancement between different regions. Though the treatment did not appear to significantly aid extraction of full root system architectures from the surrounding soil, it did allow the xylem and phloem units of seminal roots and the vascular morphology within rhizobial nodules to be clearly visualized. The nonionic, low-osmolality contrast agent Niopam appeared to be well tolerated by the plant, whereas Gastrografin showed evidence of toxicity. In summary, the use of iodine-based contrast media allows usually poorly contrasting root structures to be visualized nondestructively using X-ray μCT. In particular, the vascular structures of roots and rhizobial nodules can be clearly visualized in situ.

Hyperacute bilateral parotitis: An unusual manifestation of iodide mumps

We report a case of hyperacute bilateral parotitis, where the patient developed bilateral parotid swelling within minutes, following administration of low-osmolar iodinated contrast agent. The condition, often called “iodide mumps” usually has a late onset ranging from hours to days. Recognition of early onset of the condition is important to avoid unnecessary investigations as the condition usually follows a benign course.

Effect of contrast media on urinary cytopathology specimens.

Urological dogma dictates that washings collected from the urinary tract for cytological assessment must be performed without interference from contrast agents that may alter cellular integrity and diagnostic interpretation. In practice, the initial contrast used to outline the upper tracts is commonly discarded with subsequent saline washings sent for cytology. We hypothesize that contrast washings do not affect the morphology of urothelial carcinoma cells or the integrity of cytology interpretation. Samples obtained from (1) human bladder cell lines; (2) urine from a human xenograft bladder cancer model using UC-3 cells; and (3) patients with urothelial carcinoma were subjected to various experimental solutions (water, saline, urine, and dilutions of contrast media) for different exposure times. After exposure to various different solutions, samples underwent cytological analysis to assess morphologic and degenerative changes. No cytological differences were seen when cells were exposed to ionic, hyperosmolar, or non-ionic low-osmolar contrast agents for any exposures up to five minutes. Cells exposed to mixtures of contrast agents and urine also demonstrated no evidence of degenerative change. Cells exposed to water for greater than one minute demonstrated significant hydropic degeneration impacting cytological interpretation. At 40 minutes or later, all reagents caused severe degeneration when evaluating urine samples from the mouse bladder cancer model and from patients undergoing urothelial carcinoma. Commonly used contrast agents have no effect on urinary cytology up to five minutes. Contrast washings of the urinary tract should not be discarded and can be sent for cytological diagnosis if fixed within this time period.

Predicting Risk of Contrast-Induced Nephrotoxicity in Hospitalized Patients Undergoing Computed Tomography Using the Mehran Stratification Score

We read with interest the comprehensive review article on contrast-induced nephrotoxicity (CIN) by Nicola et al in Current Problems in Diagnostic radiology, including the most recent controversies about CIN. When discussing the role of risk factors for CIN, the authors state that “owing to the cumulative effects of multiple risk factors, an assessment tool is needed to estimate the possible level of damage,” and introduce the risk stratification score developed by Mehran et al from a large cohort of patient who underwent coronary angiography, which may predict the risk of CIN and of dialysis. Published in 2004, the Mehran risk stratification system (MRSS) involves a CIN score sheet based upon the presence of multiple risk factors including hypotension, intra-aortic balloon pump, congestive heart failure, chronic kidney disease (CKD), advanced age, anemia, diabetes, and contrast medium volume. At most general hospitals, some of these conditions are very common in hospitalized patients who undergo contrast-enhanced computed tomography (CT) for investigation of several different disorders. Therefore, at our department we tried to prospectively assess the usefulness of the MRSS in inpatients who received contrastenhanced body CT and had sufficient clinical and laboratory follow-up during hospitalization. Whereas the MRSS is validated in patients receiving intra-arterial contrast medium during coronary catheterization, to the best of our knowledge its use in CT has not been previously reported in literature. The study lasted 2 months and included 92 patients with estimated glomerular filtration rate (eGFR) below 60 mL/min and 71 matched controls with normal baseline renal function and similar age, sex distribution, and prevalence of comorbidities. The CKD group underwent CIN prophylaxis according to the European Society of Urogenital Radiology guidelines, including isotonic saline or sodium bicarbonate hydration, administration of N-acetylcysteine, and discontinuation of nephrotoxic medications. Standard weight-adjusted doses of low-osmolar contrast agents (either iopromide 370 mg I/mL or iomeprol 350 mg I/mL) were administered.

Commentary on ‘Contrast Induced Nephropathy and Long-term Renal Decline After Percutaneous Transluminal Angioplasty for Symptomatic Peripheral Arterial Disease’

Contrastinducednephropathy(CIN)asaresultoftheadministration of radiocontrast generally leads to reversible acute kidney injury. In patients with no risk, CIN is minor and insignificant (less than 1%). 1 In patients at risk(diabetes mellitus, chronic kidneydisease) the risk isup to 15%. 2 Other factorsthatcontributeto CINarepercutaneous coronary interventions with athero-embolization during catheter manipulation, hypovolemia, or advanced heart failure with reduced renal perfusion, but also contrast related factors (type, dose). In this issue of the European Journal of Vascular and Endovascular Surgery, Sigterman and colleagues 3 report 13% of CIN after endovascularprocedureforsymptomaticperipheralarterialdisease(PAD). They identified as risk factors, pre-operative anemia, critical limb ischemia, and low pre-intervention estimated glomerular filtration rate (eGFR). 3 These findings should be taken with caution. The prospective study included only patients with single radiocontrast use. Even a “homogenous” group does not represent the real world.The BASIL trial showed that 1.9e2.4 total number of endovascular interventions are necessary inpatientswith critical limb ischemia. 4 The authorsexcludedfromthecurrentstudypatientswithendstagerenal disease.What attracts attention to this paper isthe awareness of the existence of CIN in patients having endovascular treatment of PAD. The clinical implication of CIN awareness must result in the implementation of preventive measures (before, during, and after the intervention). It is obligatory to consider potentially nephrotoxic drugs and stop them: metformin, dipyridamole, NSAIDs, but also several ACE inhibitors and angiotensin II receptor blockers (Sartans). The use of potentially nephro-protective drugs such as antioxidants (N-acetylcysteine, ascorbic acid), or statins should be taken into account. 4 Considering the type of radiocontrast agent, clinicians must find a balance between the dose and the toxicity (isomolar and low osmolar contrast agents are less nephrotoxic) and the image quality. Insufficient image quality may require a second investigation, and results in radiocontrast accumulation. Adequate oral or intravenous hydration is essential. However, in the study hydration was used selectively only in patients with low eGFR.The benefit of decline in creatinine level and eGFR was to be expected also in patients with normal eGFR. Every vascular center should specify, according to international guidelines, their standard protocol to prevent CIN. One step forward might be a personalized endovascular intervention booklet, where the creatinine level and preventive measures can be documented in order to identify those patients with continuous decline of renal function. The use of alternative methods could eliminate or reduce radiocontrast during endovascular interventions. The value of intravascular ultrasound (IVUS) as a guide to treatment, and optimizing the length of the stent and its sizing is of no concern. In arteries with calcified, thrombotic lesions, the risk of distal embolization during the procedure is real, so that visualization of the foot and lower leg arteries is important. CO2 angiography is often “assisted” by initial or final single contrast use, and the image quality is worse than in conventional angiography. The overlay, 2D perfusion angiography, or wide range of 3D imaging tools, which are in use for complex aortic aneurysms, might be an option: translation to real life and PAD is on the waiting list. Patient specific rehearsal and pre-operative simulation might reduce radiocontrast use in complex aorto-iliac lesions, especially when a contralateral approach is used for the treatment iliac and femoral lesions; but there is a long way to go. 5 In the meantime, practitioners should not frighten patients by saying they will “lose their kidney” if they undergo any diagnostic/therapeutic radiocontrast intervention.They just have to use preventive measures to hamper renal function decline and to consider the possibility of applying alternative diagnostic/therapeutic methods.