Assessment of Utilization and Pharmacovigilance Based on Spontaneous Adverse Event Reporting of Gadopentetate Dimeglumine as a Magnetic Resonance Contrast Agent After 45 Million Administrations and 15 Years of Clinical Use

Investigating the Role of Sulfate Groups for the Binding of Gd3+ Ions to Glycosaminoglycans with NMR Relaxometry

Glycosaminoglycans (GAGs) are highly negatively charged macromolecules with a large cation binding capacity, but their interaction potential with exogeneous Gd³⁺ ions is under‐investigated. These might be released from chelates used as Gadolinium‐based contrast agents (GBCAs) for clinical MR imaging due to transmetallation with endogenous cations like Zn²⁺. Recent studies have quantified how an endogenous GAG sequesters released Gd³⁺ ions and impacts the thermodynamic and kinetic stability of some GBCAs. In this study, we investigate and compare the chelation ability of two important GAGs (heparin and chondroitin sulfate), as well as the homopolysaccharides dextran and dextran sulfate that are used as models for alternative macromolecular chelators. Our combined approach of MRI‐based relaxometry and isothermal titration calorimetry shows that the chelation process of Gd³⁺ into GAGs is not just a long‐range electrostatic interaction as proposed for the Manning model, but presumably a site‐specific binding. Furthermore, our results highlight the crucial role of sulfate groups in this process and indicate that the potential of a specific GAG to engage in this mechanism increases with its degree of sulfation. The transchelation of Gd³⁺ ions from GBCAs to sulfated GAGs should thus be considered as one possible explanation for the observed long‐term deposition of Gd³⁺in vivo and related observations of long‐term signal enhancements on T₁‐weighted MR images.

An NMR relaxometry approach for quantitative investigation of the transchelation of gadolinium ions from GBCAs to a competing macromolecular chelator

Gadolinium-based contrast agents (GBCAs) have been used in clinical Magnetic Resonance Imaging (MRI) for more than 30 years. However, there is increasing evidence that their dissociation in vivo leads to long-term depositions of gadolinium ions in the human body. In vitro experiments provide critical insights into kinetics and thermodynamic equilibria of underlying processes, which give hints towards the in vivo situation. We developed a time-resolved MRI relaxometry-based approach that exploits distinct relaxivities of Gd3+ in different molecular environments. Its applicability to quantify the transmetallation of GBCAs, the binding of Gd3+ to competing chelators, and the combined transchelation process is demonstrated. Exemplarily, the approach is applied to investigate two representative GBCAs in the presence of Zn2+ and heparin, which is used as a model for a macromolecular and physiologically occurring chelator. Opposing indirect impacts of heparin on increasing the kinetic stability but reducing the thermodynamic stability of GBCAs are observed. The relaxivity of resulting Gd-heparin complexes is shown to be essentially increased compared to that of the parent GBCAs so that they might be one explanation for observed long-term MRI signal enhancement in vivo. In forthcoming studies, the presented method could help to identify the most potent Gd-complexing macromolecular species.

Pharmacovigilance and radiologists: How well do they get along?

OBJECTIVES

Considering the growing use of imaging modalities and contrast agents, radiologists are prone to encounter adverse drug reactions (ADR). In the current study, we mainly aim to evaluate the knowledge of radiologists regarding pharmacovigilance (PV). Also, we intend to gather information about their previous ADR experiences. Secondarily, we hope to increase the awareness about contrast-medium-related ADRs and attract attention to the importance of properly reporting these ADRs.

METHODS

A survey was generated by using an online survey webpage, and the relevant link was e-mailed to radiologists and radiology residents. The survey begins with a short explanation about the study. The second section contains questions about PV knowledge level, and the final section aims to gather information about the experienced ADRs.

RESULTS

The survey was completed by 202 participants. 65.3% stated that they were aware of PV. 24.8% of the participants said that they know the national PV program. 97% told that they knew the term ADR. 66.3% of the participants encountered an ADR. 53.7% of them reported these ADRs. 70.8% of them reported these ADRs to a clinician.

CONCLUSIONS

Radiologists encounter ADRs almost as frequently as the other doctors. Their awareness about PV is similar with other healthcare professionals. They have fewer information about TUFAM and PvCPs. Radiologists generally prefer to communicate with a clinician about an ADR. Overall condition of radiologists about PV is quite similar with other healthcare professionals and education can improve it, as for the others.

ADVANCES IN KNOWLEDGE

Radiologists encounters ADRs almost as frequently as the other doctors. Overall condition of radiologists about PV is quite similar with other healthcare professionals and education can improve it, as for the others.

Baseline characteristics, diagnostic efficacy, and peri-examinational safety of IV gadoteric acid MRI in 148,489 patients

BACKGROUND

Magnetic resonance imaging (MRI) examinations with intravenous (IV) contrast are performed worldwide in routine daily practice. In order to detect and enumerate even rare adverse events (AE) and serious adverse events (SAE), and to relate them with patients' baseline characteristics and diagnostic effectiveness, high quantity sample size is necessary.

PURPOSE

To assess safety, diagnostic effectiveness, and baseline characteristics of patients undergoing IV gadoteric acid (Dotarem®) MRI in routine practice.

MATERIAL AND METHODS

Data from two observational post-marketing surveillance (PMS) databases compiled by 139 and 52 German centers in 2004-2011 and 2011-2013, respectively, were pooled, yielding data on a total of 148,489 patients examined over a 10-year period. Radiologists used a standardized questionnaire to report data including patient demographics, characteristics of MR examinations, and results in terms of diagnosis and patient safety.

RESULTS

Overall, 712 AEs were reported in 467 (0.3%) patients, mainly nausea (n = 224, 0.2%), vomiting (n = 29, <0.1%), urticaria (n = 20, <0.1%), and feeling hot (n = 13, <0.1%). AEs were considered related to gadoteric acid in 362 (0.2%) patients. Higher frequencies of AEs were observed among patients with a previous reaction to a contrast agent (2.0%), liver dysfunction (0.7%), bronchial asthma (0.7%), and a history of allergies (0.6%). There were 49 SAEs in 18 (<0.1%) patients, including two children. No fatal SAE was reported. Examinations were diagnostic in 99.8% of all patients, and image quality was excellent or good in 97.7% of the patients.

CONCLUSION

Gadoteric acid is a safe peri-examinational and effective contrast agent for MRI in routine practice.

Evaluating the Patient with Reported Gadolinium-Associated Illness

INTRODUCTION

Gadolinium-based contrast agents (GBCAs) have been increasingly used in clinical practice since their introduction in the 1980s. Recently, increased public attention has been given to patients who report new symptoms following GBCA exposure. This review details the current knowledge surrounding GBCAs, with a focus on the known and proposed disease states that may be associated with GBCAs. Recommendations for the appropriate clinical workup of a patient suspected of having symptoms attributable to gadolinium exposure are included.

DISCUSSION

GBCAs are known to precipitate the disease state nephrogenic systemic fibrosis (NSF), a syndrome characterized by skin thickening in patients with preexisting renal disease. An additional syndrome, termed gadolinium deposition disease, has been proposed to describe patients with normal renal function who develop an array of symptoms following GBCA exposure. While there is a potential physiologic basis for the development of this condition, there is no conclusive evidence to support a causal relationship between GBCA administration and the reported symptoms yet. Clinical evaluation revolves around focused history-taking and physical examination, given the absence of a reliable link between patient symptoms and measured gadolinium levels. There are no recommended treatments for suspected gadolinium deposition disease. Chelation therapy, which is not approved for this indication, carries undue risk without documented efficacy.

CONCLUSIONS

The extent to which GBCAs contribute to clinically relevant adverse effects remains an important and evolving field of study. NSF remains the only proven disease state associated with GBCA exposure. Additional data are required to evaluate whether other symptoms should be attributed to GBCAs.

Incidence and Risk Factors for Gadolinium-Based Contrast Agent Immediate Reactions

Since their clinical introduction in 1988, gadolinium-based contrast agents (GBCAs) have demonstrated an excellent safety profile with a reported acute adverse reaction rate ranging from 0.01% to 2%. By comparison, the acute adverse reaction rate of low osmolar nonionic computed tomography contrast agents (CTCs) ranges from 0.7% to 3.1%. Many of the risk factors associated with CTC reactions (drug allergies, asthma, atopy, prior contrast reaction) also point toward an increased incidence of acute adverse events to GBCAs. With CTCs, an increased adverse event rate was associated with ionic preparations and high osmolality. In response to concerns for nephrogenic systemic fibrosis, GBCAs are now selected for their augmented chemical stability. These agents possess some combination of macrocyclic chelates or ionic preparations. With their improved chemical stability, these agents also possess higher osmolality and the increased potential to elicit an acute adverse reaction. In light of these concerns, researchers are now focusing greater efforts on reexamining acute adverse reactions to GBCAs and whether there is an increased association with certain agents. In addition to hypersensitivity reactions, this article will also discuss contrast extravasations, safety of GBCAs for pregnant and nursing patients, and the potential nephrotoxic effects of GBCAs.

Diagnostic efficacy and safety of gadoteric acid MR mammography in 1537 patients

OBJECTIVES

To perform a large-scale multicenter post-marketing surveillance study for analyzing diagnostic effectiveness and safety of intravenous (IV) gadoteric acid (Dotarem^®) in magnetic resonance (MR) mammography under daily practice conditions.

MATERIALS AND METHODS

Patients underwent high-resolution MR mammography with gadoteric acid in 15 German centers. Radiologists used a standardized questionnaire to report data including patient demographics and medical history, characteristics of MR examination and results in terms of diagnosis and safety for the patient.

RESULTS

A total of 1537 patients were examined. In 99.2% of all patients, a diagnosis was established. In 91.6% of all patients, image quality was excellent or good. Histopathological examinations were performed for 232 of 1537 patients (15.1%) with invasive ductal carcinoma being the most frequent diagnosis (109 patients, 47.0%). Based on histopathology as the standard of reference, IV gadoteric acid-enhanced MR mammography confirmed diagnoses of invasive ductal carcinoma in 93.5% of the patients. Adverse drug reactions occurred in 5 of 1537 patients (0.3%) and were classified as serious in one case (tachycardia, dysphagia, urticaria, rash). All patients with adverse drug reactions fully recovered after the examination.

CONCLUSION

This noninterventional surveillance study shows IV gadoteric acid to be a safe and effective contrast agent for use in MR mammography.

Safety of Gadobutrol: Results From 42 Clinical Phase II to IV Studies and Postmarketing Surveillance After 29 Million Applications

OBJECTIVE

The aim of this study was to provide a systematic safety analysis of gadobutrol after more than 29 million applications in clinical routine.

MATERIALS AND METHODS

Forty-two clinical development phase II to IV studies on gadobutrol or comparator and the postmarketing safety surveillance database for gadobutrol (1998-2015) were analyzed. Adverse events (AEs) and drug-related AEs were evaluated in the clinical development database and spontaneous adverse drug reactions (ADRs) in the postmarketing database. Subgroup analyses were run on patients with special medical history and on patients of different age groups.

RESULTS

In the clinical development studies, 6809 and 2184 patients received gadobutrol or comparators, respectively. The incidence of drug-related AEs was 3.5% for both groups. With the exception of nausea (0.7% related cases in both groups), all other drug-related AEs were 0.3% or less in both groups. Hypersensitivity reactions were sporadic (<0.1%). Patients with history of allergies to contrast agents experienced slightly more drug-related AEs. No differences were seen between age groups.The overall reporting rate of ADRs from postmarketing surveillance was 0.05%. The most frequent ADRs were anaphylactoid/hypersensitivity reactions, nausea, vomiting, and dyspnea.For 3 single-agent reports of nephrogenic systemic fibrosis, using a conservative approach, association with gadobutrol could not be excluded.

CONCLUSIONS

Gadobutrol is well tolerated and has a favorable safety profile for patients of all age groups.

Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions

The release of pharmaceuticals and personal care products (PPCPs) to the soil-water environment necessitates understanding of PPCP transport behavior under conditions that account for dynamic flow and varying redox states. This study investigates the transport of two organometallic PPCPs, Gd-DTPA and roxarsone (arsenic compound) and their metal salts (Gd(NO3)3, AsNaO2); Gd-DTPA is used widely as a contrasting agent for MRI, while roxarsone is applied extensively as a food additive in the broiler poultry industry. Here, we present column experiments using sand and Mediterranean red sandy clay soil, performed under several redox conditions. The metal salts were almost completely immobile. In contrast, transport of Gd-DTPA and roxarsone was affected by the soil type. Roxarsone was also affected by the different redox conditions, showing delayed breakthrough curves as the redox potential became more negative due to biological activity (chemically-strong reducing conditions did not affect the transport). Mechanisms that include adsorptive retardation for aerobic and nitrate-reducing conditions, and non-adsorptive retardation for iron-reducing, sulfate-reducing and biologically-strong reducing conditions, are suggested to explain the roxarsone behavior. Gd-DTPA is found to be a stable complex, with potential for high mobility in groundwater systems, whereas roxarsone transport through groundwater systems is affected by redox environments, demonstrating high mobility under aerobic and nitrate-reducing conditions and delayed transport under iron-reducing, sulfate-reducing and biologically-strong reducing conditions.

25 Years of Contrast-Enhanced MRI: Developments, Current Challenges and Future Perspectives

In 1988, the first contrast agent specifically designed for magnetic resonance imaging (MRI), gadopentetate dimeglumine (Magnevist(®)), became available for clinical use. Since then, a plethora of studies have investigated the potential of MRI contrast agents for diagnostic imaging across the body, including the central nervous system, heart and circulation, breast, lungs, the gastrointestinal, genitourinary, musculoskeletal and lymphatic systems, and even the skin. Today, after 25 years of contrast-enhanced (CE-) MRI in clinical practice, the utility of this diagnostic imaging modality has expanded beyond initial expectations to become an essential tool for disease diagnosis and management worldwide. CE-MRI continues to evolve, with new techniques, advanced technologies, and novel contrast agents bringing exciting opportunities for more sensitive, targeted imaging and improved patient management, along with associated clinical challenges. This review aims to provide an overview on the history of MRI and contrast media development, to highlight certain key advances in the clinical development of CE-MRI, to outline current technical trends and clinical challenges, and to suggest some important future perspectives.

FUNDING

Bayer HealthCare.

Assessment of rates of acute adverse reactions to gadobenate dimeglumine: review of more than 130,000 administrations in 7.5 years

OBJECTIVE

The purpose of this study was to determine the incidence of adverse events associated with gadobenate dimeglumine over 7.5 years in a major hospital system consisting of both academic and community hospitals.

SUBJECTS AND METHODS

As part of a regular and continuous prospective quality assurance project, MRI technologists contemporaneously recorded all gadolinium-based contrast administrations and any associated adverse reactions, including type of reaction and treatment rendered, between August 1, 2005, and March 14, 2013. Weekly data review was performed by the director of MRI services, who evaluated data both by individual site and by comparison among the participating hospitals and sites within the hospital system. Comparison between reaction rates at different sites was performed with a chi-square test.

RESULTS

Over 7.5 years, 132,252 doses of gadobenate dimeglumine were administered, and 236 reactions were recorded (0.18% of contrast-enhanced examinations). Of these, 133 (56.4% of all adverse reactions) required treatment and 12 (5.1%) qualified as serious. Reaction rates were significantly different between academic (0.23%) and community (0.07%) hospitals (p<0.001). Reaction rates were higher in the initial years of the study, tapering to a lower baseline rate, which was maintained over more than 5 years. The findings were consistent with the Weber and Lalli effects reported in the literature on other pharmaceutical agents.

CONCLUSION

Rates of adverse reactions to gadobenate dimeglumine recorded over 7.5 years were comparable to those reported for other gadolinium-based contrast agents examined over smaller time ranges and populations. The findings reinforce the relatively robust safety profile of this agent.

[Contrast agents in radiology: current agents approved, recommendations, and safety aspects]

The manuscript summarizes current approved contrast media and their indications. Contrast agents that are discussed include iodinated contrast agents, magnetic resonance (MR) contrast agents, and ultrasound contrast agents. Allergic and non-allergic renal adverse events are described. The clinical issue of metformin and the administration of contrast agents are updated. Nephrogenic systemic fibrosis (NSF) is discussed and safety issues of available MR contrast agents are analyzed. The most recent changes in European Society of Urogenital Radiology (ESUR) guidelines are also presented.

Gadolinium-containing magnetic resonance contrast media: investigation on the possible transchelation of Gd³⁺ to the glycosaminoglycan heparin

Retention of gadolinium (Gd) in biological tissues is considered an important cofactor in the development of nephrogenic systemic fibrosis (NSF). Research on this issue has so far focused on the stability of Gd-based contrast media (GdCM) and a possible release of Gd³⁺ from the complex. No studies have investigated competing chelators that may occur in vivo. We performed proton T(1) -relaxometry in solutions of nine approved GdCM and the macromolecular chelator heparin (250 000 IU per 10 ml) without and with addition of ZnCl₂. For the three linear, nonspecific GdCM complexes, Omniscan®, OptiMARK® and Magnevist®, 2 h of incubation in heparin at 37 °C in the presence of 2.0 mm ZnCl₂ led to an increase in T₁-relaxivity by a factor of 7.7, 5.6 and 5.1, respectively. For the three macrocyclic complexes, Gadovist®, Dotarem® and Prohance®, only a minor increase in T₁-relaxivity by a factor of 1.5, 1.6 and 1.7 was found, respectively. Without addition of ZnCl₂, no difference between the two GdCM groups was observed (factors of 1.4, 1.2, 1.1, 1.3, 1.5 and 1.4, respectively). The increase in T₁-relaxivities observed for linear GdCM complexes may be attributable to partial transchelation with formation of a macromolecular Gd-heparin complex. For comparison, mixing of GdCl₃ and heparin results in a 8.7-fold higher T₁-relaxivity compared with a solution of GdCl₃ in water. Heparin is a glycosaminoglycan (GAG) and as such occurs in the human body as a component of the extracellular matrix. GAGs generally are known to be strong chelators. Gd³⁺ released from chelates of GdCM might be complexed by GAGs in vivo, which would explain their retention in biological tissues. Plasma GAG levels are elevated in end-stage renal disease; hence, our results might contribute to the elucidation of NSF.

MRI contrast agents: basic chemistry and safety

Magnetic resonance imaging (MRI) contrast agents are pharmaceuticals used widely in MRI examinations. Gadolinium-based MRI contrast agents (GBCAs) are by far the most commonly used. To date, nine GBCAs have been commercialized for clinical use, primarily indicated in the central nervous system, vasculature, and whole body. GBCAs primarily lower the T(1) in vivo to create higher signal in T(1)-weighted MRI scans where GBCAs are concentrated. GBCAs are unique among pharmaceuticals, being water proton relaxation catalysts whose effectiveness is characterized by a rate constant known as relaxivity. The relaxivity of each GBCAs depends on a variety of factors that are discussed in terms of both the existing agents and future molecular imaging agents under study by current researchers. Current GBCAs can be divided into four different structural types (macrocyclic, linear, ionic, and nonionic) based on the chemistry of the chelating ligands whose primary purpose is to protect the body from dissociation of the relatively toxic Gd(3+) ion from the ligand. This article discusses how the chemical structure influences inherent and in vivo stability toward dissociation, and how it affects important formulation properties. Although GBCAs have a lower rate of serious adverse events than iodinated contrast agents, they still present some risk.

Safety and adverse effects during 24 hours after contrast-enhanced MRI with gadobenate dimeglumine (MultiHance) in children

BACKGROUND

Gadolinium-based MR contrast agents have long been considered safe for routine diagnostic imaging. However, the advent of nephrogenic systemic fibrosis (NSF) among certain patients with severe renal insufficiency has brought the issue of safety into question. Nowhere is safety of greater concern than among children who frequently require multiple contrast-enhanced MRI examinations over an extended period of time.

OBJECTIVE

To retrospectively evaluate the safety of gadobenate dimeglumine for contrast-enhanced (CE) MRI across a range of indications.

MATERIALS AND METHODS

Two hundred pediatric inpatients (age: 4 days to 15 years) underwent CE MRI as part of clinical routine. The children received a gadobenate dimeglumine dose of either 0.05 mmol/kg body weight (liver, abdominal imaging, musculoskeletal imaging, brain and other rare indications) or 0.1 mmol/kg bodyweight (cardiovascular imaging, MR-urography). Young (< 8 years) children with congenital heart disease were intubated and underwent MRA evaluation with controlled ventilation. Monitoring for adverse events was performed for at least 24 h after each gadobenate dimeglumine injection. Depending on clinical necessity, laboratory measurements and, in some cases, vital sign and ECG determinations were made before and after contrast injection. Safety was evaluated by age group, indication and dose administered.

RESULTS

No clinically adverse events were reported among children who had one MRI scan only or among children who had several examinations. There were no changes in creatinine or bilirubin levels even in very young children.

CONCLUSIONS

No adverse events were recorded during the first 24 h following administration of gadobenate dimeglumine in 200 children.

Effect of abrupt substitution of gadobenate dimeglumine for gadopentetate dimeglumine on rate of allergic-like reactions

PURPOSE

To evaluate the effect of abruptly substituting gadobenate dimeglumine for gadopentetate dimeglumine on allergic-like reactions.

MATERIALS AND METHODS

The institutional review board approved and waived patient consent for this HIPAA-compliant retrospective study. Allergic-like reactions related to gadolinium-based contrast media were assessed 2 years before and 3.5 years after gadobenate dimeglumine was substituted for gadopentetate dimeglumine. Reaction rates and severity were compared by using χ(2) tests, Fisher exact tests, odds ratios (ORs), and confidence intervals (CIs).

RESULTS

Allergic-like reactions (137 mild, 19 moderate, and six severe) occurred in 162 (0.15%) of 105 607 injections of gadolinium-based contrast media (gadopentetate dimeglumine, 31 540; gadobenate dimeglumine, 66 152; other, 7915). Gadobenate dimeglumine was associated with significantly more overall (0.19% [123 of 66 152] vs 0.08% [24 of 31 540]; OR, 2.4; 95% CI: 1.6, 3.8; P < .0001) and mild (0.16% [107 of 66 152] vs 0.06% [18 of 31 540]; OR, 2.8; 95% CI: 1.7, 4.7; P < .0001) allergic-like reactions than was gadopentetate dimeglumine. The reaction rate for gadobenate dimeglumine peaked (maximum per quarter, 0.38% [16 of 4262]; minimum per quarter, 0.07% [three of 4237]) in the 2nd year after it replaced gadopentetate dimeglumine (maximum per quarter, 0.10% [four of 4122]; minimum per quarter, 0.05% [two of 4222]) and then declined in the 3rd year. The final gadobenate dimeglumine reaction rate (last 3 quarters, 0.12% [17 of 14 387]) did not significantly differ from the original baseline reaction rate with gadopentetate dimeglumine.

CONCLUSION

After gadobenate dimeglumine was substituted for gadopentetate dimeglumine, a significant transient increase occurred in the frequency of reported allergic-like reactions that demonstrated a temporal pattern suggestive of the Weber effect (a transient increase in adverse event reporting that tends to peak in the 2nd year after a new agent or indication is introduced). © RSNA, 2012.

Fluid flow along venous adventitia in rabbits: is it a potential drainage system complementary to vascular circulations?

Background

Our previous research and other studies with radiotracers showed evidence of a centripetal drainage pathway, separate from blood or lymphatic vessels, that can be visualized when a small amount of low molecular weight tracer is injected subcutaneously into a given region on skin of humans. In order to further characterize this interesting biological phenomenon, animal experiments are designed to elucidate histological and physiologic characteristics of these visualized pathways.

Methods

Multiple tracers are injected subcutaneously into an acupuncture point of KI3 to visualize centripetal pathways by magnetic resonance imaging or fluorescein photography in 85 healthy rabbits. The pathways are compared with venography and indirect lymphangiography. Fluid flow through the pathways is observed by methods of altering their hydrated state, hydrolyzing by different collagenases, and histology is elucidated by optical, fluorescein and electron microscopy.

Results

Histological and magnetic imaging examinations of these visualized pathways show they consist of perivenous loose connective tissues. As evidenced by examinations of tracers’ uptake, they appear to function as a draining pathway for free interstitial fluid. Fluorescein sodium from KI3 is found in the pathways of hind limbs and segments of the small intestines, partial pulmonary veins and results in pericardial effusion, suggesting systematical involvement of this perivenous pathway. The hydraulic conductivity of these pathways can be compromised by the collapse of their fiber-rich beds hydrolyzed by either of collagenase type I, III, IV or V.

Conclusions

The identification of pathways comprising perivenous loose connective tissues with a high hydraulic conductivity draining interstitial fluid in hind limbs of a mammal suggests a potential drainage system complementary to vascular circulations. These findings may provide new insights into a systematically distributed collagenous connective tissue with a circulatory function and their potential relevance to the nature of acupuncture meridians.

Tolerability and diagnostic value of gadoteric acid in the general population and in patients with risk factors: results in more than 84,000 patients

PURPOSE

To review the tolerability and diagnostic effectiveness of gadoteric acid under daily practice conditions in the general population and at-risk patients.

MATERIALS AND METHODS

A total of 84,621 patients (45.4% men, 54.6% women, mean age 52.0 ± 16.9 years) were studied in 129 German centers. Patients underwent contrast-enhanced magnetic resonance imaging (MRI) using gadoteric acid (Gd-DOTA, Dotarem(®), Guerbet, Roissy CdG, France) as IV contrast medium (mean volume, 16.4 ml). 22.9% of the patients had at least one risk factor (e.g., allergies, previous allergic reaction to a contrast medium, and renal impairment). 554 patients received pretreatment before contrast medium administration (0.7%). Adverse events were documented and image quality was assessed.

RESULTS

A diagnosis was possible in 99.7% of all cases. Image quality was rated good or excellent in 97.1%. Adverse events (e.g., nausea, vomiting, and urticaria) were observed in 0.34% of the examinations and were mostly rated as minor. There were 8 patients with serious adverse events. The adverse event rate was significantly higher in patients with a history of allergies (0.62%; p<0.001) and in patients with a previous allergic reaction to contrast medium (1.23%; p<0.001). There was no elevated incidence of adverse events in patients with renal impairment.

CONCLUSION

Gadoteric acid is a well-tolerated MRI contrast medium in patients with and without risk factors that is associated with a low rate of adverse events and good or excellent image quality in most patients.

Incidence of immediate gadolinium contrast media reactions

OBJECTIVE

Our objective was to determine the incidence of immediate adverse events for gadolinium-based contrast agents.

MATERIALS AND METHODS

All gadolinium-based contrast agent adverse events reported to radiology quality assurance committees were graded according to American College of Radiology criteria and divided by the total number of injections to determine incidence during the past 10 years. For each event, an age- and examination-matched control patient was identified to compare sex, weight, creatinine, eosinophil count, allergic history and gadolinium-based contrast agent dose differences. The U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) database was analyzed to compare local experience to national trends.

RESULTS

Abdominal MRI had the highest rates of adverse events, 0.013% compared with brain (0.0045%, p < 0.001) or spine (0.0034%, p < 0.001). Adverse events were more likely in women, with a female to male ratio of 3.3, and in patients with history of prior allergic reactions (p < 0.001). Immediate adverse events rates were 0.2, 0.5, 1.2, and 3.3 per 1,000 injections for gadodiamide, gadopentetate dimeglumine, gadobenate dimeglumine, and gadoteridol, respectively. Gadobenate dimeglumine had more severe patient reactions, including three patients who arrested (defined as the patient becoming unresponsive and the code team being called), one of whom died. From 2004 to 2009, the FDA received reports on 40 gadolinium-based contrast agent U.S. deaths unrelated to nephrogenic systemic fibrosis, with an incidence per million doses of 0.15, 0.19, 0.97, 2.7, and 0.7 for gadodiamide, gadoversetimide, gadopentetate dimeglumine, gadobenate dimeglumine, and gadoteridol, respectively.

CONCLUSION

This limited retrospective analysis shows that gadolinium-based contrast agents are very safe, with only rare reports of death, and raises the possibility that nonionic linear gadolinium-based contrast agents and gadopentetate dimeglumine may have fewer severe immediate adverse events compared with gadobenate dimeglumine.

Acute adverse reactions to gadopentetate dimeglumine and gadobenate dimeglumine: experience with 32,659 injections

OBJECTIVE

The purpose of this study was to retrospectively assess the frequency, manifestations, and severity of acute adverse reactions associated with administration of two gadolinium-based contrast agents to patients who underwent MRI at a single large academic institution.

MATERIALS AND METHODS

Data from continuous quality assurance records on the number of administrations of and acute adverse reactions to gadopentetate dimeglumine and gadobenate dimeglumine at our institution October 2007 to December 2008 were tabulated and analyzed. During the investigation period, 32,659 administrations of gadolinium-based contrast agents were performed for MRI examinations. Of these, 27,956 administrations were gadopentetate dimeglumine, and 4,703 administrations were gadobenate dimeglumine. Data were collected on the frequency and severity of acute adverse reactions.

RESULTS

A total of 51 acute adverse reactions occurred in 50 patients (16 men, 34 women; mean age, 48 years), accounting for 0.16% of all administrations (51/32,659). Thirty-eight reactions (38/27,956, 0.14%) were associated with gadopentetate dimeglumine, and 13 (13/4,703, 0.28%) were associated with gadobenate dimeglumine. Forty-three reactions were mild, six were moderate, and two were severe. The severe reactions occurred with the use of gadobenate dimeglumine.

CONCLUSION

The rates of acute adverse reactions to gadopentetate dimeglumine and gadobenate dimeglumine were 0.14% and 0.28%, respectively. The overall adverse reaction rate was 0.16% in our patient sample. Direct comparison of adverse reaction rates of the two agents was not possible because of the retrospective uncontrolled study design.

Prevalence of acute adverse reactions to gadobutrol--a highly concentrated macrocyclic gadolinium chelate: review of 14,299 patients from observational trials

OBJECTIVE

To determine the safety and tolerability of gadobutrol in a large number of non-selected patients from routine clinical radiology practices.

MATERIALS AND METHODS

Six prospectively planned, observational surveillance studies were conducted at more than 300 institutions in Europe and Canada from 2000 to 2007. Demographic and medical status data, details of the diagnostic procedure, contrast agent administration and adverse drug reaction (ADR) data were collected using a standardized questionnaire.

RESULTS

A total of 14,299 patients were enrolled. The mean age of the patients was 53.7 years; 1.3% of the patients were <18 years old and 40.8% were 60 years or older. The body regions most frequently examined were head/neck/brain (54.3%), followed by spine (7.2%), pelvis/joints/limbs (6.7%) and multiple body regions (6.4%). Gadobutrol-enhanced magnetic resonance angiography (MRA) was performed in 14.7% of patients. Overall, the mean volume of gadobutrol administered for contrast-enhanced magnetic resonance imaging was 12 mL (0.16 mmol gadolinium [Gd]/kg body weight [BW]; mean BW: 75.5 kg), whereas for contrast-enhanced MRA the mean volume was 15.7 mL (0.21 mmol Gd/kg BW). Seventy-eight of the 14,299 patients (0.55%) reported at least one ADR. Two (0.01%) serious ADRs were reported. The most frequently reported ADR was nausea, which occurred in 36 patients (0.25%).

CONCLUSION

Gadobutrol 1.0M is very well tolerated and has a good safety profile. The occurrence of ADRs observed following the intravenous injection of gadobutrol is comparable with the published data of other Gd-based contrast agents.

Stability of gadolinium-based magnetic resonance imaging contrast agents in human serum at 37 degrees C

OBJECTIVES

Assessment of the complex stability and Gd3+ dissociation rate of all marketed gadolinium-based MRI contrast agents (GBCA) in human serum at pH 7.4 and 37 degrees C.

METHODS AND RESULTS

The kinetic profiles of Gd3+ dissociation of GBCAs were determined by incubation for 15 days in human serum from healthy volunteers at a concentration of 1 mmol/L, pH 7.4, and 37 degrees C. The initial rates of Gd3+ release and the amounts of Gd3+ released after 15 days were established by HPLC-ICP-MS analysis. In an attempt to simulate the situation in patients with end-stage renal disease who often have elevated serum phosphate levels, the influence of 10 mmol/L phosphate on Gd3+ dissociation was also investigated.The GBCAs were grouped and ranked in the following order according to their stabilities in native human serum at pH 7.4 and 37 degrees C [% Gd release after 15 days and initial rate (%/d) (95% confidence interval) in brackets]. NONIONIC LINEAR GBCAS: Optimark [21 (19-22) %, 0.44 (0.40-0.51) %/d) and Omniscan [20 (17-20) %, 0.16 (0.15-0.17) %/d]. IONIC LINEAR GBCAS: Magnevist [1.9 (1.2-2.0) %, 0.16 (0.12-0.36) %/d], Multihance [1.9 (1.3-2.1) %, 0.18 (0.13-0.38) %/d], Vasovist [1.8 (1.4-1.9) %, 0.12 (0.11-0.18) %/d], and Primovist [1.1 (0.76-1.2) %, 0.07 (0.05-0.08) %/d]. MACROCYCLIC GBCAS: Gadovist, Prohance, and Dotarem (all < limit of quantification of 0.1%, <0.007%/d).In the presence of additional 10 mmol/L phosphate in serum, the initial Gd release rates of the nonionic linear GBCAs, Omniscan, and Optimark increased about 100-fold, and, after 15 days, the amount of Gd3+ released from these agents was more than 75% higher than in native serum. The initial rates found for the ionic linear GBCAs increased about 12- to 30-fold, but, despite this, increase in the initial rate, the amount of Gd3+ released after 15 days was comparable to that in native serum. The elevated phosphate level did not lead to any measurable release of Gd3+ from the 3 macrocyclic GBCAs.

CONCLUSIONS

The release of Gd from all linear Gd3+ complexes in human serum was several orders of magnitude greater than predicted by the conditional stability constants. After 15 days, release of Gd3+ from the nonionic linear GBCAs was about 10 times higher than from the ionic linear GBCAs. Elevated serum phosphate levels accelerated the release of Gd3+ from nonionic linear GBCAs and, to a lesser degree, from the ionic linear GBCAs. All 3 macrocyclic GBCAs remained stable in human serum at both normal and elevated phosphate levels.

Assessment of adverse reaction rates to a newly approved MRI contrast agent: review of 23,553 administrations of gadobenate dimeglumine

OBJECTIVE

With the introduction of a newly approved MR contrast agent across a health care system encompassing 13 hospitals and associated imaging centers, the opportunity arose to compare the rates of adverse reactions in seven of these facilities with reactions reported in the literature. Data were collected to assess the relative risk of using gadobenate dimeglumine compared with published data for other approved agents and for this agent in preclinical testing.

SUBJECTS AND METHODS

As part of regular quality assurance procedures, technologists recorded contrast administrations and related adverse reactions, including the type of reaction and treatments rendered, on log sheets. All data were reviewed weekly by the institutional director of MR services and were evaluated globally and by site.

RESULTS

Over 13 months, 23,553 doses of gadobenate dimeglumine were administered. One hundred seventy-eight reactions were recorded (0.76% of contrast-enhanced examinations), of which 22 required treatment (13% of reactions) and eight (5% of reactions) qualified as serious.

CONCLUSION

With the introduction of the most recent MR contrast agent approved for use in the United States, our interest in its substantial potential clinical benefits that would result from its increased relaxivity was balanced by concern that the rate of adverse effects may increase. This concern has been ameliorated with the findings of rates of adverse reactions that are comparable to those published for other MR contrast agents.

Visualized regional hypodermic migration channels of interstitial fluid in human beings: are these ancient meridians?

BACKGROUND

Since the 1980s, many studies have indicated there are hypodermic migration channels of radiotracer along meridians independent of lymphatic and blood vessels in vivo. However, the radioactive trajectories were not clear enough to identify the anatomic structures in the living body.

OBJECTIVES

To establish an alternative method to image the specific fluid pathways, we hypothesized that a minimal amount of low molecular weight tracer could enter the specific channels and by magnetic resonance imaging technique, we could image the regional channels originating from the acupoints on 6 yin meridians of forearm and lower leg.

DESIGN AND RESULTS

Seven (7) healthy volunteers were injected hypodermically with a minimal amount of tracer into 6 acupoints on 6 yin meridians of the hand and foot. We found a total of 6 regional specific channels in one forearm and one lower leg of each subject, respectively, but no specific channels were visualized following injection of the tracer into the sites of nonacupoints. Magnetic resonance angiography confirmed the specific channels were not the superficial veins in the subcutis. Subsequent acupuncture needling studies revealed that migration of tracer along each of the specific channels could not be interrupted by acupuncture needling and remained intact, which was different from the nature of either lymphatics or blood vessels.

CONCLUSIONS

We imaged 6 regional migration channels originating from 6 acupoints on 6 yin meridians of hand and foot by injecting a minimal amount of tracer into acupoints directly in humans. The responses of the subcutaneous specific channels to acupuncture needling are different from those of lymphatic or blood vessels and coincide partially with the characteristics of acupuncture therapeutics, suggesting the existence of meridian-like channels in humans. These findings may contribute to further research on the specific interstitial fluid drainage.

Assessment of renal function with dynamic contrast-enhanced MR imaging

MR imaging is a promising noninvasive modality that can provide a comprehensive picture of renal anatomy and function in a single examination. The advantages of MR imaging are its high contrast and temporal resolution and lack of exposure to ionizing radiation. In the past few years, considerable progress has been made in development of methods of renal functional MR imaging and their applications in various diseases. This article reviews the key factors for acquisition and analysis of dynamic contrast-enhanced renal MR imaging (MR renography) and the most significant developments in this field over the past few years.

New proposal for the staging of nonalcoholic steatohepatitis: evaluation of liver fibrosis on Gd-EOB-DTPA-enhanced MRI

PURPOSE

We investigated whether the gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI was useful for nonalcoholic steatohepatitis (NASH) staging based on the severity of liver fibrosis.

MATERIALS AND METHODS

Twenty-one male Sprague-Dawley rats aged 7 weeks, weighing about 150g in NASH group were fed a choline-deficient diet for 4, 7 or 10 weeks, and seven rats in the control group were fed a standard diet (n=7). After the feeding period, the rats were subjected to contrast-enhanced MRI (2D-FLASH; TR/TE=101/2.9ms, flip angle 90 degrees ). Gd-DTPA (0.1mmol Gd/kg) and Gd-EOB-DTPA (0.025mmol Gd/kg) were injected at 24-h intervals, and the speed of contrast injection was 1mL/s. Signal intensities of the liver were measured and the relative enhancement (RE), the time of maximum RE (T(max)) and elimination half-life of RE (T(1/2)) in the liver were compared. The fibrosis rate (%) was calculated with the following formula: fibrosis/whole areax100.

RESULTS

The fibrosis rates of each group were as follows: 0.52, 0.79, 2.84, and 0.50% (4, 7, 10 weeks and control groups). The fibrosis rate of the 10 weeks group was significantly higher than the control and 4 or 7 weeks groups. Although there was no difference between the T(max) and T(1/2) of each group after Gd-DTPA injection, the T(max) and T(1/2) of the 10 weeks group were significantly prolonged in comparison with the control and 4 or 7 weeks groups after Gd-EOB-DTPA injection (p<0.01). There was a significant correlation between the fibrosis rate and T(max) or T(1/2) after Gd-EOB-DTPA injection (r=0.90 or 0.97).

CONCLUSION

It was possible to assess the progress of liver fibrosis in NASH by evaluating the signal intensity-time course on Gd-EOB-DTPA-enhanced MRI.

Nephrogenic systemic fibrosis: an emerging entity

Nephrogenic systemic fibrosis (NSF) is a progressive disorder which has been seen only in patients with chronic kidney disease. It is associated with fibrosis of the skin and connective tissue throughout the body. The skin thickens and becomes hard, rigid, and coarse, which severely restricts movement of the joints. It can also lead to widespread fibrosis of internal organs involving lungs, heart, diaphragm, esophagus, and skeletal muscle, and in some cases may lead to death. Based on case series reports and skin biopsy showing gadolinium (Gd) ions, NSF has been directly linked to Gd contrast exposure given during MRI/MRA. There are over 250 reported cases of NSF worldwide with hundreds still not reported or remaining undiagnosed. Symptoms of NSF appear within 2-75 days, with a mean of 25 days after exposure to Gd contrast. This disorder is not well understood, and more research is needed to obtain information about how Gd causes this condition. Currently there is no effective treatment, so prevention is the only way to avoid this serious illness.

A preclinical study to investigate the development of nephrogenic systemic fibrosis: a possible role for gadolinium-based contrast media

OBJECTIVES

Several recent publications have suggested an association between the administration of gadolinium (Gd)-based contrast agents and the occurrence of Nephrogenic Systemic Fibrosis (NSF), an acquired disorder marked by skin thickening and fibrosis occurring in patients with severe renal dysfunction. The aim of this study was to establish a preclinical experimental setting to investigate the possible link between NSF and Gd-based contrast agents, and specifically the role of Gd and/or depletion of endogenous metal ions as possible triggers for NSF.

MATERIALS AND METHODS

Thirty-five healthy male rats received repeated intravenous injections of Magnevist (gadopentetate dimeglumine; Gd-DTPA), Omniscan (gadodiamide; Gd-DTPA-BMA), or gadodiamide without caldiamide at a dose of 2.5 mmol Gd/kg body weight over at least 20 days to simulate the exposure to Gd-containing contrast agents in patients with severe renal dysfunction. In addition, caldiamide (the excess ligand in Omniscan) and Gd-ethylenediamine tetraacetic acid (Gd-EDTA) as a positive control, and saline as a negative control were studied. Histopathologic and immunohistochemical analysis of the skin was performed. Gd and zinc concentrations were measured in skin, femur, and liver tissue by atomic emission spectrometry.

RESULTS

Rats receiving Gd-EDTA, gadodiamide without caldiamide, and Omniscan developed epidermal ulceration and acanthosis, dermo-epidermal clefts, minimal-to-slight dermal fibrosis, and increased dermal infiltration of different cells, partly positive for CD34 fibrocytes. No such NSF-like macroscopic lesions were observed in the saline, caldiamide, and Magnevist groups. High Gd concentrations in the skin were found in the Gd-EDTA, gadodiamide without caldiamide, and Omniscan groups. In the Magnevist group, Gd levels in the skin were 10-times lower than in the Omniscan-treated animals but elevated compared with saline.

CONCLUSIONS

A preclinical experimental setting has been established where NSF-like lesions could be observed. The link between the application of Gd-based contrast media and the induction of NSF-like lesions was established. The data indicate that the observed skin lesions are related to the release of Gd and not to the depletion of endogenous ions. The investigations further suggest potential importance of the stability of Gd-based contrast agents.

Biochemical safety profiles of gadolinium-based extracellular contrast agents and nephrogenic systemic fibrosis

Gadolinium (Gd)-based paramagnetic contrast agents are relatively safe when used in clinically recommended doses. However, with the rapidly expanding body of literature linking Gd-based paramagnetic contrast agents and nephrogenic systemic fibrosis (NSF), awareness of the potential side effects and adverse reactions from Gd is now an important requirement for practicing radiologists. In addition to the ongoing accumulation and analyses of clinical NSF data, it is also essential for the practicing radiologist to understand the biochemical characteristics of the extracellular Gd-chelates. The purpose of this review is to consolidate and update the available information on known side effects, adverse reactions, and toxicity of the Gd chelates, with particular emphasis on the potential mechanisms of NSF.

Advances in magnetic resonance (2007)

Advances in clinical magnetic resonance (MR) are discussed in this review in the context of publications from Investigative Radiology during 2006 and 2007. The articles relevant to this topic, published during this 2 year time period, are considered as organized by anatomic region. An additional final focus of discussion is in regards to those studies involving MR contrast media.

Potential of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) for differential diagnosis of nonalcoholic steatohepatitis and fatty liver in rats using magnetic resonance imaging

RATIONALE AND OBJECTIVES

To investigate the potential of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) for the differential diagnosis of nonalcoholic steatohepatitis (NASH) and fatty liver (FL).

METHODS

Twenty-one male rats were divided into 3 groups. Seven rats in the NASH group were fed a choline-deficient diet for 10 weeks, and the 7 rats in the FL group were fed a standard diet also containing 1% (wt/wt) orotic acid for 4 weeks. As a control, 7 rats were fed a standard diet. After the feeding period, all rats were subjected to contrast-enhanced dynamic and delayed MRI with a 2D-FLASH technique. Gd-DTPA (0.1 mmol Gd/kg) and Gd-EOB-DTPA (0.025 mmol Gd/kg) were injected into the tail vein at 24-hour intervals. Signal intensities of the liver were measured for each MR image and the relative enhancement (RE) was calculated. In addition, the time of maximum RE (Tmax) and the half-life of RE (T1/2) in liver were compared. After MRI, the liver was histologically analyzed to evaluate steatosis, hepatitis, and fibrosis.

RESULTS

Diffuse macrovesicular steatosis and severe fibrosis were observed in the NASH group, whereas diffuse microvesicular steatosis and rare fibrosis were observed in the FL group. Immediately after the Gd-DTPA injection, the RE in the liver of each group temporarily increased, and thereafter, rapid RE reduction was observed. However, a continuous increase and subsequent slow reduction of RE were induced after the Gd-EOB-DTPA injection. Although there was no difference between the Tmax and T1/2 of each group after the Gd-DTPA injection, Tmax and T1/2 of the NASH group were significantly prolonged in comparison with FL and control groups after the Gd-EOB-DTPA injection (P < 0.01).

CONCLUSIONS

It was possible to differentiate NASH and FL by evaluating the SI time course on Gd-EOB-DTPA enhanced MRI.

Contrast-enhanced magnetic resonance imaging of central nervous system tumors: agents, mechanisms, and applications

Brain tumors are one of the most common neoplasms in young adults and are associated with a high mortality and disability rate. Magnetic resonance imaging (MRI) is widely accepted to be the most sensitive imaging modality in the assessment of cerebral neoplasms. Because the detection, characterization, and exact delineation of brain tumors require a high lesion contrast that depends on the signal of the lesion in relation to the surrounding tissue, contrast media is given routinely. Anatomical and functional, contrast agent-based MRI techniques allow for a better differential diagnosis, grading, and especially therapy decision, planing, and follow-up. In this article, the basics of contrast enhancement of brain tumors will be reviewed. The underlying pathology of a disrupted blood-brain barrier and drug influences will be discussed. An overview of the currently available contrast media and the influences of dosage, field strength, and application on the tumor tissue contrast will be given. Challenging, contrast-enhanced, functional imaging techniques, such as perfusion MRI and dynamic contrast-enhanced MRI, are presented both from the technical side and the clinical experience in the assessment of brain tumors. The advantages over conventional, anatomical MRI techniques will be discussed as well as possible pitfalls and drawbacks.

Nephrogenic Systemic Fibrosis

OBJECTIVES

Nephrogenic systemic fibrosis (NSF) is a rare acquired disorder that was first recognized in 1997. Presented is a retrospective review of 6 cases of NSF diagnosed by skin biopsy in our institution during the past 4 years and their relationship to gadodiamide exposure.

METHODS AND RESULTS

Patient age ranged from 23 to 71 years. The onset of symptoms consistent with NSF was between 19 days and 2 months after gadodiamide exposure. Five patients had severe renal impairment and started dialysis around the period of gadodiamide exposure (1 day before the 37 days after contrast administration). The sixth patient had a clotted access at the time of a contrast-enhanced magnetic resonance venogram and was hence not being adequately dialyzed. The dose of gadodiamide ranged from 16 to 40 mL (0.11 to 0.36 mmol/kg). Despite having normal serum bicarbonate, 5 of the 6 patients had an elevated anion gap metabolic acidosis.

CONCLUSIONS

In our 6 patients, all had either failing native or transplant kidneys at the time of gadodiamide exposure. The development of NSF was temporally related to gadodiamide injection, suggesting as the etiology dechelation of the agent and thus emphasizing the need for change in clinical practice.

Cardiovascular Safety of Gadoterate Meglumine (Gd-DOTA)

OBJECTIVES

Gadolinium complexes are not considered to be a drug class at high risk for prolonging cardiac repolarization, which can lead to potentially life-threatening arrhythmias such as torsade de pointes. However, only limited robust data are available on these compounds despite their extensive use as contrast enhancers in magnetic resonance imaging. We present an overview of recent cardiovascular safety data obtained on gadoterate meglumine (Gd-DOTA).

MATERIALS AND METHODS

Cardiovascular safety was evaluated by "state-of-the-art" nonclinical ex vitro (dog Purkinje fibers) and in vivo studies in both normal (dogs) and sensitized animal models (rabbits) and in patients with various diseases in a specific clinical trial.

RESULTS

In all of these studies, Gd-DOTA did not show any direct deleterious effect on cardiac electrophysiology and especially on ventricular repolarization.

CONCLUSION

These results confirmed the good safety profile of Gd-DOTA derived from postmarketing evaluations. Nonspecific gadolinium complexes used for magnetic resonance contrast enhancement do not constitute a class-at-risk for drug-related arrhythmias.

Advances in Magnetic Resonance (2006)

Advances in the field of magnetic resonance (MR) as it pertains to clinical diagnostic radiology are examined in this review on the basis of publications in Investigative Radiology over the past 2 years (2005-2006). The articles published during that timeframe are discussed, organizationally wise, by anatomic region with an additional focus on studies involving MR contrast media.