Safety Of Gadolinium-based Contrast Agents Research Articles

#1502 Short-term effects of gadolinium and gadoteric acid on kidney — impact on inflammation

Abstract Background and Aims The nephrotoxicity of free gadolinium [Gd (III)] has been reported, raising concerns about the safety of gadolinium-based contrast agents (GBCA), widely used in magnetic resonance imaging. The GBCA with macrocyclic structure, such as gadoteric acid (Gd-DOTA), appear as more stable. Using human proximal tubular cells cultures, we found that free Gd (III) triggers death by apoptosis and necrosis, and increases the expression of modulators of inflammation, hypoxia and fibrosis, which are known as major risk factors for the development and worsening of kidney disease. Our aim was, using animal models, to evaluate the short-term effects of Gd (III) and of gadoteric acid on inflammatory biomarkers, at blood and renal tissue levels. Method Wistar rats were exposed to a single dose of Gd (III) or Gd-DOTA (groups A and B, respectively); a control group was also included (C). After 48h, blood and kidney samples were collected. The plasma levels of interleukin (IL)6 and transforming growth factor (TGF) beta 1 were assessed by ELISA; the kidney gene expression of IL6 (il6), TGF beta 1 (tgbf1) and nuclear factor-kappa B (nfkb1) was determined through qPCR. Results Gd (III) group (A) presented higher circulating IL6 levels (P = 0.001) and increased kidney gene expression of il6 (P = 0.013), tgbf1 (P = 0.006) and nfkb1 (P = 0.011) than the control group (C); compared to Gd-DOTA group (B), the IL6 plasma concentration (P = 0.005) and tgbf1 mRNA levels were also higher (P = 0.004). The Gd-DOTA group (B) presented increased gene expression of il6 (P = 0.006) than the control group (C). Conclusion Short-term exposition to free Gd (III) induced an inflammatory response, shown by the increase in circulating IL6, and in kidney gene expression of il6, tgbf1 and nfkb1. The exposition to Gd-DOTA was associated with a lower inflammatory response, showing only increased kidney gene expression of il6. Despite the much safer profile for Gd-DOTA, further studies are warranted, evaluating other biomarkers, to clarify the short-term, and even the long-term effects, of these compounds. Acknowledgements This work was financed by FCT through the project 2022.08400.PTDC; FCT, in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB.

#1613 Gadolinium and gadoteric acid's short-term impact on kidney function and lipid profile

Abstract Background and Aims Concerns regarding the safety of gadolinium-based contrast agents (GBCA), which are often employed in medical imaging, have been raised in light of reports of free gadolinium's [Gd (III)] cytotoxicity. It appears that GBCAs having macrocyclic structures, like gadoteric acid (Gd-DOTA), are more stable and less toxic. Previous work from our group found that Gd (III) promotes inflammation and fibrosis in proximal tubular cells cultures. A disturbance of lipid metabolism was also reported, accompanied by the build-up of lipid droplets, lipid peroxidation and the overexpression of genes linked to lipogenesis and lipolysis. The aim of this study was to evaluate the short-term effects of Gd (III) and of Gd-DOTA on renal function and lipid metabolism biomarkers, using an animal model. Method Male Wistar rats were exposed to a single dose of Gd (III) or Gd-DOTA (groups A and B, respectively); a control group was also included (C). Blood was collected after 48h of exposure to compounds. We evaluated circulating levels of renal function biomarkers—creatinine and cystatin—using a routine automated assay and ELISA, respectively. The lipid profile was also determined including triglycerides (TG), total cholesterol, HDL-cholesterol, LDL-cholesterol, and oxidized LDL (oxLDL) levels. Results Gd (III) group (A) presented significantly higher circulating cholesterol (P=0.006) and LDL-cholesterol (P<0.001) and lower TG (P<0.001) levels than the control group (C); a non-significant increment in cystatin was also observed for group A. The Gd-DOTA group (B) only presented lower TG levels (P=0.002) compared to the control group (C), being similar to those presented by group A. Both exposed groups (A and B) presented non-significantly higher oxLDL levels compared to the control group. Conclusion Single exposition to free Gd (III) induced prompt changes in lipid profile, with little short-term influence in traditional kidney biomarkers. The exposition to Gd-DOTA was associated with lower disturbance in lipids and lipoproteins (only lower TG levels) and imperceptible renal changes. Despite the significantly safer profile for Gd-DOTA, further studies are necessary, testing different biomarkers, to clarify the short-term, and even the long-term impacts, of these molecules. Acknowledgements This work was financed by FCT through the project 2022.08400.PTDC; FCT, in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB.

A Review on the Design of Carbon-Based Nanomaterials as MRI Contrast Agents.

The administration of magnetic resonance imaging (MRI) contrast agents (CAs) has been conducted since 1988 by clinicians to enhance the clarity and interpretability of MR images. CAs based on gadolinium chelates are the clinical standard used worldwide for the diagnosis of various pathologies, such as the detection of brain lesions, the visualization of blood vessels, and the assessment of soft tissue disorders. However, due to ongoing concerns associated with the safety of gadolinium-based contrast agents, considerable efforts have been directed towards developing contrast agents with better relaxivities, reduced toxicity, and eventually combined therapeutic modalities. In this context, grafting (or encapsulating) paramagnetic metals or chelates onto (within) carbon-based nanoparticles is a straightforward approach enabling the production of contrast agents with high relaxivities while providing extensive tuneability regarding the functionalization of the nanoparticles. Here, we provide an overview of the parameters defining the efficacy of lanthanide-based contrast agents and the subsequent developments in the field of nanoparticular-based contrast agents incorporating paramagnetic species.

Rapid Formation of Methemoglobin via Nitric Oxide Delivery for Potential Use as an MRI Contrast Agent.

Contrast-enhanced magnetic resonance angiography is a vital tool for evaluating vascular pathology. However, concerns about the limitations and safety of gadolinium-based contrast agents have led to an interest in alternative agents. Methemoglobin (metHb) increases the T1-weighted signal intensity of the magnetic resonance image of blood and could provide a safe and effective alternative. MetHb can be produced by the reaction of nitric oxide (NO) gas with oxyhemoglobin followed by natural conversion back to hemoglobin by cytochrome b5 reductase. Since rapid production of metHb via NO has not been studied, the effectiveness of producing metHb via NO delivery to blood was evaluated using a hollow-fiber module. MetHb production began immediately and > 90% conversion was achieved within 10min. MetHb remained stable for at least 90min when NO delivery was removed following metHb formation. Comparison of experimental data for metHb formation with model predictions showed that only a fraction of the NO delivered was utilized for metHb production, suggesting an additional fast reaction of NO with other blood constituents. Directly delivering NO to blood for the rapid formation of metHb provides a potential platform for producing metHb as an alternative contrast agent.

Effects of Gadolinium Deposition in the Brain on Motor or Behavioral Function: A Mouse Model.

Background Recent studies showing gadolinium deposition in multiple organs have raised concerns about the safety of gadolinium-based contrast agents (GBCAs). Purpose To explore whether gadolinium deposition in brain structures will cause any motor or behavioral alterations. Materials and Methods This study was performed from July 2019 to December 2020. Groups of 17 female BALB/c mice were each repeatedly injected with phosphate-buffered saline (control group, group A), a macrocyclic GBCA (group B), or a linear GBCA (group C) for 8 weeks (5 mmol per kilogram of bodyweight per week for GBCAs). Brain MRI studies were performed every other week to observe the signal intensity change caused by the gadolinium deposition. After the injection period, rotarod performance test, open field test, elevated plus-maze test, light-dark anxiety test, locomotor activity assessment test, passive avoidance memory test, Y-maze test, and forced swimming test were performed to assess the locomotor abilities, anxiety level, and memory. Among-group differences were compared by using one-way or two-way factorial analysis of variance with Tukey post hoc testing or Dunnett post hoc testing. Results Gadolinium deposition in the bilateral deep cerebellar nuclei was confirmed with MRI only in mice injected with a linear GBCA. At 8 weeks, contrast ratio of group C (0.11; 95% CI: 0.10, 0.12) was higher than that of group A (-2.1 × 10-3; 95% CI: -0.011, 7.5 × 10-3; P < .001) and group B (2.7 × 10-4; 95% CI: -8.2 × 10-3, 8.7 × 10-3; P < .001). Behavioral analyses showed that locomotor abilities, anxiety level, and long-term or short-term memory were not different in mice injected with linear or macrocyclic GBCAs. Conclusion No motor or behavioral alterations were observed in mice with brain gadolinium deposition. Also, the findings support the safety of macrocyclic gadolinium-based contrast agents. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Chen in this issue.

Patterns of use, effectiveness and safety of gadolinium contrast agents: a European prospective cross-sectional multicentre observational study

BackgroundThe EU gadolinium-based contrast agents (GBCA) market has changed in recent years due to the European Medicines Agency decision to suspend the marketing authorisation of linear GBCA and the marketing authorisation of new generic macrocyclic GBCA. The study aims to understand the patterns of (GBCA) use, and to study the effectiveness and safety of GBCA in routine practice across Europe.MethodsProspective, cross-sectional, multicentre, observational study in patients undergoing contrast-enhanced magnetic resonance. Reported usage patterns included indication, referral and examination details. Assessment of effectiveness included changes in radiological diagnosis, diagnostic confidence and image quality. Safety data were collected by spontaneous patient adverse event (AE) reporting.Results2118 patients were included from 8 centres across 5 European countries between December 2018 and November 2019. Clariscan, Dotarem (gadoteric acid), Gadovist (gadobutrol) and ProHance (gadoteridol) were utilised in 1513 (71.4%), 356 (16.8%), 237 (11.2%) and 12 (0.6%) patients, respectively. Most were performed in CNS-related indications (46.2%). Mean GBCA doses were 0.10 mmol/kg body weight, except for Gadovist (mean 0.12 mmol/kg). GBCA use increased confidence in diagnosis in 96.2% of examinations and resulted in a change in radiological diagnosis in 73.9% of patients. Image quality was considered excellent or good in 96.1% of patients and across all GBCA. Four patients reported AEs (0.19%), with only 1 (0.05%) considered serious.ConclusionsThis European study confirmed that GBCAs are used appropriately in Europe for a wide range of indications. The study demonstrated a significant increase in diagnostic confidence after GBCA use and confirmed the good safety profile of GBCAs, with comparable results for all agents used.

Longitudinal changes in extent of late gadolinium enhancement in repaired Tetralogy of Fallot: a retrospective analysis of serial CMRs

BackgroundRight ventricular (RV) late gadolinium enhancement (LGE) occurs due to surgical scarring and RV remodeling, and has been shown to be associated with clinical outcomes in Tetralogy of Fallot (TOF). However, it is not known if cardiovascular magnetic resonance (CMR) LGE extent progresses over time, and therefore, it is not known if serial reassessment of LGE is necessary. We determined the rate of progression in the extent of RV LGE on serial CMR examinations in repaired TOF.MethodsRetrospective review of 127 patients after TOF repair (49% male, median age at first CMR 18.9 years (Interquartile range (IQR) 13.3,27.0) who had at least two CMRs (median follow-up duration of 4.0 years (IQR 2.1,5.9)) was performed. 84/127 patients had no interventions between serial CMRs (Group 1) while 43/127 patients had transcatheter or surgical intervention between CMRs (Group 2). The extent of RV LGE was assessed using 2 methods: a semiquantitative RV LGE score and a quantitative RV LGE extent expressed as % of RV mass. Mixed effects linear regression modeling to estimate changes in LGE over time.ResultsRV LGE was present in all patients on the first CMR. % RV LGE extent and LGE score did not increase over time in either patient group. The mean 5 year rates of change were small and negative for both % RV LGE extent [− 2.3 (95% CI − 2.9, − 1.8, p < 0.001) in Group 1, and − 1.9 (95% CI − 3.2, − 0.7, p = 0.004) in Group 2], and RV LGE score [− 0.9 (95% CI − 1.1, − 0.6, p < 0.001) in Group 1, and − 0.5 (95% CI − 1.1, − 0.0, p = 0.047) in Group 2].ConclusionsIn this serial CMR evaluation of children and adults with repaired TOF, no significant progression in the extent of RV LGE was seen on intermediate term follow-up. Given recent concerns regarding the safety of gadolinium-based contrast agents, frequent assessment of LGE may not be necessary in follow-up.

Image quality of late gadolinium enhancement in cardiac magnetic resonance with different doses of contrast material in patients with chronic myocardial infarction

BackgroundContrast-enhanced cardiac magnetic resonance (CMR) is pivotal for evaluating chronic myocardial infarction (CMI). Concerns about safety of gadolinium-based contrast agents favour dose reduction. We assessed image quality of scar tissue in CMRs performed with different doses of gadobutrol in CMI patients.MethodsInformed consent was waived for this Ethics Committee-approved single-centre retrospective study. Consecutive contrast-enhanced CMRs from CMI patients were retrospectively analysed according to the administered gadobutrol dose (group A, 0.10 mmol/kg; group B, 0.15 mmol/kg; group C, 0.20 mmol/kg). We calculated the signal-to-noise ratio for scar tissue (SNRscar) and contrast-to-noise ratio between scar and either remote myocardium (CNRscar-rem) or blood (CNRscar-blood).ResultsOf 79 CMRs from 79 patients, 22 belonged to group A, 26 to group B, and 31 to group C. The groups were homogeneous for age, sex, left ventricular morpho-functional parameters, and percentage of scar tissue over whole myocardium (p ≥ 0.300). SNRscar was lower in group A (46.4; 40.3–65.1) than in group B (70.1; 52.2–111.5) (p = 0.013) and group C (72.1; 59.4–100.0) (p = 0.002), CNRscar-rem was lower in group A (62.9; 52.2–87.4) than in group B (96.5; 73.1–152.8) (p = 0.008) and in group C (103.9; 83.9–132.0) (p = 0.001). No other significant differences were found (p ≥ 0.335).ConclusionsGadobutrol at 0.10 mmol/kg provides inferior scar image quality of CMI than 0.15 and 0.20 mmol/kg; the last two dosages seem to provide similar LGE. Thus, for CMR of CMI, 0.15 mmol/kg of gadobutrol can be suggested instead of 0.20 mmol/kg, with no hindrance to scar visualisation. Dose reduction would not impact on diagnostic utility of CMR examinations.

Comparison of Tmax values between full- and half-dose gadolinium perfusion studies

AHA guidelines recommend use of perfusion imaging for patient selection in the 6–24 h window. Recently, the safety of gadolinium-based contrast agents for MR perfusion imaging has been questioned based on findings that gadolinium accumulates in brain tissue. Regulatory bodies have recommended to limit the use of gadolinium-based contrast agents where possible. Focusing specifically on the time to maximum of the tissue residue function (Tmax) parameter, used in DAWN and DEFUSE 3, we hypothesized that half-dose scans would yield a similar Tmax delay pattern to full-dose scans. We prospectively recruited 10 acute ischemic stroke patients imaged with two perfusion scans at their follow-up visit, one with a standard dose gadolinium followed by a half-dose injection a median of 7 min apart. The brain was parcellated into a grid of 3 × 3 regions and the mean of the difference in Tmax between the 3 × 3 regions on the half- and full-dose Tmax maps was 0.1 s (iqr 0.38 s). The fraction of brain tissue that differed by no more than ±1 s was 93.7%. In patients with normal or modest Tmax delays, half-dose gadolinium appears to provide comparable Tmax measurements to those of full-dose scans.

Iron Sucrose as MRI Contrast Agent in Ischemic Stroke Model

Despite the growing concern about the safety of gadolinium-based contrast agents (GBCAs), they are still the most commonly used. Ferumoxytol, as an off-label alternative MRI contrast agent, cannot be administered by a rapid bolus for dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI). To assess the feasibility of iron sucrose (IS) as a contrast agent for MR angiography (MRA) and DSC-PWI. Prospective animal model. Thirty-six normal rats (16 for MRA, 20 for biocompability tests) and 36 occlusion of the middle cerebral artery (MCAO) model rats. 3.0T; head and neck angiography, using a fast spoiled gradient-recalled-echo (FSPGR) sequence and DSC-MRI using echo planar imaging(EPI) sequence. MRA was performed on normal rats to examine the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of different doses of IS. DSC-PWI was performed on MCAO rats at 0, 24, 48, and 72 hours postreperfusion to investigate the lesion detectability of IS. Arterial spin labeling (ASL) and DSC-PWI enhanced by GBCAs were conducted on MCAO rats as controls. Kruskal-Wallis test was used to compare qualitative assessment. One-way analysis of variance (ANOVA) was used to compare the parametric data. Pearson's r values were evaluated between relative cerebral blood flow(rCBF)-ASL, rCBF-DSCIS , and rCBF obtained from DSC-PWI enhanced by GBCA. The mean SNR and CNR of the common carotid artery at doses of 10 mg Fe/kg of IS were comparable with the standard dose of GBCAs (SNR: 68.04 ± 12.55 vs. 67.72 ± 14.66; CNR: 23.78 ± 7.21vs. 21.63 ± 6.83). In MCAO rat models, rCBF and relative cerebral blood volume (rCBV) of ipsilateral striatum declined (0.72 ± 0.14, 0.86 ± 0.11) with prolonged relative mean transit time (rMTT) and relative time-to-peak (rTTP) (1.27 ± 0.24, 1.07 ± 0.03) following occlusion. Hyperperfusion was observed in all rats at 48 and 72 hours postreperfusion, in 4/6 rats at 24 hours postreperfusion for IS-mediated DSC-PWI. IS may be an effective contrast agent for both MRA and DSC-PWI in ischemic stroke models. 1 TECHNICAL EFFICACY STAGE: 1 J. Magn. Reson. Imaging 2020;52:836-849.

Safety of gadoterate meglumine in children younger than 2years of age.

Few studies on the safety of gadolinium-based contrast agents have been performed in children with even fewer focusing on children younger than 2years of age. To assess the safety of gadoterate meglumine (Dotarem) in patients younger than 2years of age by evaluating adverse events following contrast administration. Pediatric patients younger than 2years of age undergoing magnetic resonance imaging (MRI) with and without contrast were prospectively enrolled and received a weight-based intravenous dose of gadoterate meglumine (0.1mmol/kg). The occurrence of adverse events was assessed at the time of injection, 2h after MRI, and by phone contact using a standard questionnaire 24h after MRI. Adverse events were documented including the time of onset, duration of symptoms, intensity, causality and subsequent outcome. Descriptive statistics were used to characterize patient information. One hundred fifty exams were completed in 150 patients (median age: 12.1months, age range: 0.25-23months; males: 56%). Almost all patients (97.3%) received sedation/anesthesia before and during MRI. Thirty-four adverse events were reported in 23 patients overall (15.3%; male: 73.9%; median age: 11months, age range: 3-23months). Within the initial 2h after the injection, there was one report of transient flushing/warmth and one report of vomiting, the latter of which was related to drinking formula too soon after anesthesia. Twenty-two patients (14.7%), who had all received sedation/anesthesia, experienced minor adverse events within 24h, most physiological. Fourteen patients (9.3%) reported emesis, eight (5.3%) reported transient flushing/warmth, seven (4.7%) reported nausea, one (0.7%) reported altered taste and one (0.7%) reported dizziness. No patient experienced anaphylaxis. Two patients (1.3%) reported allergic-like reactions, which consisted of wheezing or sneezing. No patient experienced adverse events directly related to gadoterate meglumine. Only two adverse events were reported to have occurred in the initial 2h after the exam, while the rest were reported on the 24-h follow-up call. The higher reported rate of adverse events in this study may be related to concomitant sedation/anesthesia as well as to overreporting from parents on the 24-h follow-up questionnaire. The study confirms a good safety profile for gadoterate meglumine in this very sensitive population.

Safety of Gadolinium-Based Contrast Agents in Patients with Stage 4 and 5 Chronic Kidney Disease: a Radiologist's Perspective.

Gadolinium-based contrast agents (GBCAs) have been used for contrast-enhanced magnetic resonance imaging (MRI) since 1988 with >450 million intravenous GBCA doses administered worldwide and overall have had an excellent safety record (1,2). Numerous studies have demonstrated the benefit of GBCAs for a variety of diagnostic indications including improving sensitivity and specificity for malignancy, demyelination, central nervous system malignancy, and infection (3⇓⇓⇓–7). Initially, it was thought that GBCAs would be safer than iodinated contrast media for patients with kidney disease because they are less nephrotoxic at clinically administered doses (8). Although some case reports have linked AKI to GBCA administration, most cases involve patients with advanced renal disease or diabetes and with doses that exceed US Food and Drug Administration (FDA) recommendations (8). The safety of GBCAs in patients with kidney disease came into question in 2006 when a strong association was found between the use of GBCAs in patients with severe kidney disease and the development of nephrogenic systemic fibrosis (NSF) (9⇓–11). NSF results in fibrosis of the skin and internal organs and can be fatal. A conclusive mechanism of causation for NSF has not been determined. Several mouse models of NSF have been developed to investigate the underlying pathophysiology; however, they tend to use doses which are higher than those approved by the FDA and older linear agents (12⇓–14). A confounding issue is that many people with severe kidney disease received multiple exposures to GBCAs and did not develop NSF. Conversely, patients with only one administration of a GBCA have developed NSF (15,16). It is unclear if this could at least partially relate to interspecies differences. Multiple factors may contribute, most notably patient-specific risk factors and the stability of the GBCA, which is …

Prospective Multicenter Study of the Safety of Gadoteridol in 6163 Patients.

BackgroundThe safety of gadolinium‐based contrast agents is of fundamental importance.PurposeTo determine the frequency and severity of immediate‐type adverse reactions to approved doses of gadoteridol in patients referred for routine gadoteridol‐enhanced MRI in actual clinical practice settings.Study TypeProspective, observational.PopulationIn all, 6163 subjects were enrolled (mean age: 56.7 ± 15.4 years; range: 6–93 years).Field Strength/Sequence1.5T and 3.0T.AssessmentAssessment was of immediate adverse reactions by the investigating radiologist using the MedDRA System Organ Class and preferred term.Statistical TestsSummary statistics for continuous variables, descriptive statistics for demographic characteristics.ResultsOverall, 19 adverse events occurred in 13 (0.21%) patients, of which 15 in 10 (0.16%) patients were considered related to gadoteridol administration. These events were evenly distributed between male and female subjects and all occurred in adults. Twelve of the 15 related events in eight (0.13%) patients were considered mild in intensity (rapidly self‐resolving), while the remaining three events in two patients (0.03%) were considered moderate in intensity. None were of severe intensity and no serious adverse events occurred.Data ConclusionThe rate of immediate‐type adverse events following exposure to approved doses of gadoteridol is extremely low, and mostly limited to transient and self‐resolving symptoms. Level of Evidence: 2 Technical Efficacy Stage: 5J. Magn. Reson. Imaging 2020;51:861–868.

Gadolinium-based contrast agents: in vitro paraoxonase 1 inhibition, in silico studies

Medications show their biological effects by interaction with enzymes, which have been known to play an essential role in the pathogenesis of many diseases. Inhibition or induction of drug metabolizing enzymes has an essential place in the drug design for many kinds of diseases including cardiovascular, neurological, metabolic, and cancer. The main goal of the current study is to contribute to this growing drug design field by observing PON1–drug interactions. In recent years, the safety of gadolinium-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI) has discussed. In the present study, paraoxonase 1 (PON1) enzyme was purified from human serum by simple chromatographic methods with 4095.24 EU mg−1 protein specific activity. The inhibitory activities of gadoteric acid, gadopentetic acid, gadoxetate disodium, and gadodiamide were investigated on PON1 activity of the enzyme. IC50 values were found in the range of 51.28 ± 0.14 to 285.80 ± 0.96 mM. Ki constants were found as 67.95 ± 0.60 mM, 104.97 ± 0.96 mM, 202.33 ± 1.75 mM, and 299.43 ± 2.64 mM for gadoteric acid, gadopentetic acid, gadoxetate disodium, and gadodiamide, respectively. While the inhibition types are determined as competitive of gadoxetate disodium and gadodiamide by the Lineweaver–Burk curves, it was noncompetitive for other compounds. In addition, the molecular docking analyses of gadoxetate disodium and gadodiamide were carried out to understand the binding interactions on the active site of the PON1 enzyme. The structure–activity relationship (SAR) of the drugs was established on the basis of different substituents and their positions in the compounds.

Safety of gadobutrol: results of a non-interventional study of 3710 patients, including 404 children.

BackgroundThe safety of gadolinium-based contrast agents is a hot topic in radiology.PurposeTo evaluate the safety profile of gadobutrol during routine use.Material and MethodsProspective, non-interventional study in 80 centers in Germany. The primary outcome was the number of adverse drug reactions (ADR) following gadobutrol administration.ResultsA total of 3710 patients were included in the analysis, including 404 children (10.9%). A total of 6026 magnetic resonance imaging examinations of organs/organ systems and 872 magnetic resonance angiography examinations were performed. A total of 22 (0.59%) patients experienced at least one ADR. Nausea and vomiting were the most frequent ADRs, experienced by nine (0.24%) and three (0.08%) patients, respectively. One serious ADR was recorded (anaphylactoid reaction). No deaths were reported.ConclusionThis non-interventional study in 3710 patients confirmed gadobutrol as a safe and reliable contrast agent in adults and children.

Gadolinium Deposition in Brain: Current Scientific Evidence and Future Perspectives.

In the past 4 years, many publications described a concentration-dependent deposition of gadolinium in the brain both in adults and children, seen as high signal intensities in the globus pallidus and dentate nucleus on unenhanced T1-weighted images. Postmortem human or animal studies have validated gadolinium deposition in these T1-hyperintensity areas, raising new concerns on the safety of gadolinium-based contrast agents (GBCAs). Residual gadolinium is deposited not only in brain, but also in extracranial tissues such as liver, skin, and bone. This review summarizes the current evidence on gadolinium deposition in the human and animal bodies, evaluates the effects of different types of GBCAs on the gadolinium deposition, introduces the possible entrance or clearance mechanism of the gadolinium and potential side effects that may be related to the gadolinium deposition on human or animals, and puts forward some suggestions for further research.

Investigation of the ototoxicity of gadoteridol (ProHance) and gadodiamide (Omniscan) in mice

Conclusion: In the mouse, when a tympanic perforation is present, gadoteridol does not seem to cause ototoxicity. Gadodiamide may cause mild ototoxicity other than toxicity to the outer hair cells of the cochlea.Objectives: Endolymphatic hydrops have been visualized through intra-tympanic injection of gadolinium-based contrast agents (GBCAs) and three-dimensional fluid-attenuated inversion recovery (3-D FLAIR) magnetic resonance imaging. However, reports on the safety of GBCAs are limited. This study aimed to assess ototoxicity of gadoteridol and gadodiamide.Method: In a prospective, randomized, controlled trial, myringotomies in the left ear were performed in 20 male C57 BL/6 mice. After testing the baseline auditory brainstem response (ABR) (range = 8–32 kHz), the test solution (gadoteridol, gadodiamide, saline, or cisplatin) was injected into the left ear. ABR testing was repeated 14 days after test solution application. In morphological experiments, images of post-mortem surface preparations were assessed for cochlear hair cell status.Results: At 14 days following gadoteridol application, there was no significant change in ABR thresholds at 8, 16, or 32 kHz. Gadodiamide application caused a significant change in the ABR threshold at 8 kHz. Apparent cochlear hair cell loss was not observed in the surface preparation after gadoteridol or gadodiamide application.

Nonenhanced MR Angiography

While nonenhanced magnetic resonance (MR) angiographic methods have been available since the earliest days of MR imaging, prolonged acquisition times and image artifacts have generally limited their use in favor of gadolinium-enhanced MR angiographic techniques. However, the combination of recent technical advances and new concerns about the safety of gadolinium-based contrast agents has spurred a resurgence of interest in methods that do not require exogenous contrast material. After a review of basic considerations in vascular imaging, the established methods for nonenhanced MR angiographic techniques, such as time of flight and phase contrast, are considered and their advantages and disadvantages are discussed. This article then focuses on new techniques that are becoming commercially available, such as electrocardiographically gated partial-Fourier fast spin-echo methods and balanced steady-state free precession imaging both with and without arterial spin labeling. Challenges facing these methods and possible solutions are considered. Since different imaging techniques rely on different mechanisms of image contrast, recommendations are offered for which strategies may work best for specific angiographic applications. Developments on the horizon include techniques that provide time-resolved imaging for assessment of flow dynamics by using nonenhanced approaches.