Administration Of Gadolinium-based Contrast Agents Research Articles

Correlation between high signal intensity in cerebrum nucleus on unenhanced T1-weighted MR images and number of previous gadolinium-based contrast agent administration

To explore the correlation between the number of previous gadolinium-based contrast agent administrations and high signal intensity (SI) in the cerebrum nucleus on unenhanced T1-weighted magnetic resonance images. Thirty-nine patients who previously underwent at least three contrast-enhanced brain MRI examinations were enrolled in the study. The right globus pallidus, right thalamus, right dentate nucleus, pons and white matter of right frontal lobe were selected as region of interests (ROI). The mean SIs of the ROI were measured on unenhanced T1-weighted images. The SI ratios of globus pallidus, right thalamus, right dentate nucleus and pons to white matter were calculated, respectively. The correlation of SI ratio variation with the number of previous contrast agent administration and clinical features was analyzed with Spearman analysis. The dentate nucleus-to-white matter SI ratios of the last and first MRI scan were 1.113±0.136 and 1.014±0.096(P<0.01), respectively; while the SI ratio differences between the last and first MRI scan of globus pallidus-to-white matter, the thalamus-to-white matter and the pons-to-white matter were not significant (all P>0.05). The dentate nucleus-to-white matter SI ratio was correlated with the number of previous gadolinium-based contrast agent administrations (r=0.329, P<0.05), but not with age, sex, underlying disease, treatment and history of diabetes (all P>0.05). High SI in the dentate nucleus on unenhanced T1-weighted images may be a consequence of the number of previous gadolinium-based contrast agent administrations.

Signal intensity at unenhanced T1-weighted magnetic resonance in the globus pallidus and dentate nucleus after serial administrations of a macrocyclic gadolinium-based contrast agent in children.

Few studies have been conducted on the relations between T1-weighted signal intensity changes in the pediatric brain following gadolinium-based contrast agent (GBCA) exposure. The purpose of this study is to investigate the effect of multiple administrations of a macrocyclic GBCA on signal intensity in the globus pallidus and dentate nucleus of the pediatric brain on unenhanced T1-weighted MR images. This retrospective study included 50 patients, mean age: 8years (standard deviation: 4.8years), with normal renal function exposed to ≥6 administrations of the same macrocyclic GBCA (gadoterate meglumine) and a control group of 59 age-matched GBCA-naïve patients. The globus pallidus-to-thalamus signal intensity ratio and dentate nucleus-to-pons signal intensity ratio were calculated from unenhanced T1-weighted images for both patients and controls. A mixed linear model was used to evaluate the effects on signal intensity ratios of the number of GBCA administrations, the time interval between administrations, age, radiotherapy and chemotherapy. T-test analyses were performed to compare signal intensity ratio differences between successive administrations and baseline MR signal intensity ratios in patients compared to controls. P-values were considered significant if <0.05. A significant effect of the number of GBCA administrations on relative signal intensities globus pallidus-to-thalamus (F[8]=3.09; P=0.002) and dentate nucleus-to-pons (F[8]=2.36; P=0.021) was found. The relative signal intensities were higher at last MR examination than at baseline (P<0.001). Quantitative analysis evaluation of globus pallidus:thalamus and dentate nucleus:pons of the pediatric brain demonstrated an increase after serial administrations of macrocyclic GBCA. Further research is necessary to fully understand GBCA pharmacokinetic in children.

Innovative Perspective: Gadolinium-Free Magnetic Resonance Imaging in Long-Term Follow-Up after Kidney Transplantation

Since the mid-1980s magnetic resonance imaging (MRI) has been investigated as a non- or minimally invasive tool to probe kidney allograft function. Despite this long-standing interest, MRI still plays a subordinate role in daily practice of transplantation nephrology. With the introduction of new functional MRI techniques, administration of exogenous gadolinium-based contrast agents has often become unnecessary and true non-invasive assessment of allograft function has become possible. This raises the question why application of MRI in the follow-up of kidney transplantation remains restricted, despite promising results. Current literature on kidney allograft MRI is mainly focused on assessment of (sub) acute kidney injury after transplantation. The aim of this review is to survey whether MRI can provide valuable diagnostic information beyond 1 year after kidney transplantation from a mechanistic point of view. The driving force behind chronic allograft nephropathy is believed to be chronic hypoxia. Based on this, techniques that visualize kidney perfusion and oxygenation, scarring, and parenchymal inflammation deserve special interest. We propose that functional MRI mechanistically provides tools for diagnostic work-up in long-term follow-up of kidney allografts.

Nephrogenic systemic fibrosis: A survey of the use of gadolinium-based contrast agents in Ghana

IntroductionThe aim of this study is to identify current practice of administration of gadolinium-based contrast agents (GBCAs) in Ghana. MethodA total of 13 MRI (magnetic resonance imaging) facilities were sent a survey questionnaire to request information on their current practice with the use of GBCAs. ResultsGadodiamide, a high risk GBCA accounted for 67% of first line agents. 5 (42%) had a departmental protocol on the administration of GBCAs with regards to its association with nephrogenic systemic fibrosis (NSF). Of the 8 that use gadodiamide, 3 check kidney function in all patients, 2 check in selected patients, and 3 do not check at all. All 3 that screen all patients do not use contrast if the patient has an eGFR (estimated glomerular filtration rate) of 30–59 ml/min, 1 considers other modality; and if the patient has an eGFR of <30 ml/min, 2 do not use contrast but consider other modality, however 1 continues with the high risk agent. ConclusionGadodiamide is widely used, with varied practice in screening for renal function, and risk factors associated with NSF. Current evidence shows that it is advisable to administer macrocyclic agents in patients with compromised renal function. It is also imperative to establish local guidelines in line with international guidelines in order to minimize the incidence of NSF.

Retention of Gadolinium-Based Contrast Agents in Multiple Sclerosis: Retrospective Analysis of an 18-Year Longitudinal Study.

Gadolinium-based contrast agents have been associated with lasting high T1-weighted signal intensity in the dentate nucleus and globus pallidus, with histopathologically confirmed gadolinium retention. We aimed to longitudinally investigate the relationship of multiple gadolinium-based contrast agent administrations to the Signal Intensity Index in the dentate nucleus and globus pallidus and any associations with cognitive function in multiple sclerosis. The Signal Intensity Index in the dentate nucleus and globus pallidus was retrospectively evaluated on T1-weighted MR imaging in an 18-year longitudinal cohort study of 23 patients with MS receiving multiple gadolinium-based contrast agent administrations and 23 healthy age- and sex-matched controls. Participants also underwent comprehensive neuropsychological testing. Patients with MS had a higher Signal Intensity Index in the dentate nucleus (P < .001), but not in the globus pallidus (P = .19), compared with non-gadolinium-based contrast agent-exposed healthy controls by an unpaired t test. Increasing numbers of gadolinium-based contrast agent administrations were associated with an increased Signal Intensity Index in the dentate nucleus (β = 0.45, P < .001) and globus pallidus (β = 0.60, P < .001). This association remained stable with corrections for the age, disease duration, and physical disability for both the dentate nucleus (β = 0.43, P = .001) and globus pallidus (β = 0.58, P < .001). An increased Signal Intensity Index in the dentate nucleus among patients with MS was associated with lower verbal fluency scores, which remained significant after correction for several aspects of disease severity (β = -0.40 P = .013). Our data corroborate previous reports of lasting gadolinium retention in brain tissues. An increased Signal Intensity Index in the dentate nucleus and globus pallidus was associated with lower verbal fluency, which does not prove causality but encourages further studies on cognition and gadolinium-based contrast agent administration.

Intrathecal Contrast-Enhanced Magnetic Resonance Imaging-Related Brain Signal Changes: Residual Gadolinium Deposition?

There have been recent studies evaluating brain magnetic resonance imaging changes in patients with normal renal function, after intravenous administration of gadolinium-based contrast agents (GBCAs). Their findings were supported by histological evidence as well and brought a new vision concerning what needs to be learned to provide better patient care. In this report, we aim to present brain magnetic resonance imaging changes after intrathecal administration of a linear ionic agent (gadopentetate dimeglumine). We evaluated hyperintensities in the deep nuclei of the brain in 6 patients with normal renal function after intrathecal administration of a linear ionic GBCA, without other confounding intravenous GBCA administrations. For visual analysis, T1 signal hyperintensity of the globus pallidus (GP), putamen, pons, and dentate nucleus (DN) were scored on a 4-point scale. For quantitative analysis, using the unenhanced T1-weighted images oval regions of interests were placed within the DN, central pons, GP, and thalamus on different image slice positions. On visual analysis, 5 patients had T1 signal hyperintensity of the DN and GP, whereas the DN/pons signal intensity and the GP/thalamus signal intensity were found to be increased in all 6. This observation not only adds to our fund of knowledge concerning biodistribution and pharmacokinetics of those agents, but also raises the question of a possible association with the glymphatic pathway.

Gadolinium Contrast Agents - Are they Really Safe?

Gadolinium-based contrast agents (GBCA) are used worldwide for enhanced MRI examinations, including heart and vessels. Gadolinium is a highly toxic heavy metal. If used in GBCA it must be tightly bound to ligands. The configuration of ligands influences the stability of the GBCA and two types of chelates have been used. Macrocyclic chelates offer better protection and binding of gadolinium ion than linear chelates with a flexible open chain - gadolinium could be more easily released from the latter ones. GBCAs are excreted from the body mostly by the kidneys, which is of importance in chronic kidney disease.Two states are related to gadolinium: nephrogenic systemic fibrosis (NSF) and gadolinium body storage. NSF is a severe and debilitating disease, directly connected to gadolinium toxicity, proven after the use of linear chelates. Due to strict recommendations of radiology societies, NSF was practically eradicated. Gadolinium deposition was observed especially in bones and in some brain areas: in dentate nucleus and in globus pallidus, even years after the GBCA administration. The form of the storage (chelated or free), as well as their clinical impact, are not clear, but first observations of "gadolinium deposition disease" have been reported.

Survey of gadolinium-based contrast agent utilization among the members of the Society for Pediatric Radiology: a Quality and Safety Committee report.

Gadolinium-based contrast agents (GBCAs) have been used for magnetic resonance (MR) imaging over the last three decades. Recent reports demonstrated gadolinium retention in patients' brains following intravenous administration. Since gadolinium is a highly toxic heavy metal, there is a potential for adverse effects from prolonged retention or deposition, particularly in children. For this reason, the Society (SPR) for Pediatric Radiology Quality and Safety committee conducted a survey to evaluate the current status of GBCAs usage among pediatric radiologists. To assess the usage of GBCAs among SPR members. An online 15-question survey was distributed to SPR members. Survey questions pertained to the type of GBCAs used, protocoling workflow, requirement of renal function or pregnancy tests, and various clinical indications for contrast-enhanced MRI examinations. A total of 163 survey responses were compiled (11.1% of survey invitations), the majority of these from academic institutions in the United States. Ninety-four percent reported that MR studies are always or usually protocoled by pediatric radiologists. The most common GBCA utilized by survey respondents were Eovist (60.7%), Ablavar (45.4%), Gadovist (38.7%), Magnevist (34.4%) and Dotarem (32.5%). For several clinical indications, survey responses regarding GBCA administration were concordant with American College of Radiology (ACR) Appropriateness Criteria, including seizures, headache and osteomyelitis. For other indications, including growth hormone deficiency and suspected vascular ring, survey responses revealed potential overutilization of GBCAs when compared to ACR recommendations. Survey results demonstrate that GBCAs are administered judiciously in children, yet there is an opportunity to improve their utilization with the goal of reducing potential future adverse effects.

Pediatric Brain: No Increased Signal Intensity in the Dentate Nucleus on Unenhanced T1-weighted MR Images after Consecutive Exposure to a Macrocyclic Gadolinium-based Contrast Agent.

Purpose To determine the effect of at least five serial injections of the macrocyclic gadolinium-based contrast agent (GBCA) gadoterate meglumine on the signal intensity (SI) of the dentate nucleus (DN) of the pediatric brain on nonenhanced T1-weighted magnetic resonance (MR) images. Materials and Methods In this retrospective, institutional review board-approved study, 41 pediatric patients (age range, 3-17 years) who were imaged in at least five consecutive 1.5-T MR examinations with the exclusive use of gadoterate meglumine (plus a final additional nonenhanced MR imaging examination) were evaluated. SI ratio differences between the first and last MR examination were calculated for DN-to-pons and DN-to-middle cerebellar peduncle (MCP) ratios in a region-of-interest-based analysis, and one-sample t tests were used to examine if the SI ratio differences differed from 0. Bayes factors were calculated to quantify the strength of evidence for each test. Results Patients underwent a mean of 8.6 ± 3.9 GBCA administrations (mean accumulated dose, 32.07 mmol ± 17.62, with an average of 16.7 weeks ± 7.9 between every administration). Both ratio differences did not differ significantly from 0 (DN-to-pons ratio: -0.0012 ± 0.0101, P = .436; DN-to-MCP ratio: 0.0007 ± 0.0088, P = .604), and one-sided Bayes factors provided substantial evidence against an SI ratio increase (0.10 for DN-to-pons ratio; 0.27 for DN-to-MCP ratio). Conclusion No increase of the SI in the DN was found after a mean of 8.6 serial injections of the macrocyclic GBCA gadoterate meglumine in pediatric patients, confirming previous studies that did not find this effect after serial injections of macrocyclic GBCAs in adults. © RSNA, 2017.

Distribution map of gadolinium deposition within the cerebellum following GBCA administration.

Gadolinium-based contrast agents (GBCAs) are an essential tool in clinical MRI. Millions of doses are administered annually to patients worldwide.1 However, free gadolinium, the basis of GBCAs, is extremely toxic in only small amounts. Gadolinium has an atomic radius similar to that of calcium and can interfere with calcium-dependent processes such as voltage-gated calcium channels or calcium-activated enzymes.1 To reduce toxicity, GBCAs are composed of gadolinium in chelated form. Following GBCA administration, presumably the gadolinium–chelate complex is excreted intact by the kidneys in patients with normal renal function. Each of the 9 Food and Drug Administration–approved MRI contrast agents has its own specific chelate, leading to variation in stabilities of the gadolinium–chelate complex. GBCAs are generally classified as either linear or macrocyclic based on chelate structure. An ionic, macrocyclic structure has the highest kinetic and thermodynamic stabilities.1

The presence of the gadolinium-based contrast agent depositions in the brain and symptoms of gadolinium neurotoxicity - A systematic review.

Background and purposeGadolinium based contrast agents (GBCAs) are widely used in magnetic resonance imaging, but recently, high signal intensity in the cerebellum structures was reported after repeated administrations of contrast- enhanced magnetic resonance images. The aim of this systematic review was to investigate the association between increased signal intensity in the dentate nucleus and globus pallidus in the brain and repeated administrations of GBCAs. Additionally, we focused on possible short- and long-term consequences of gadolinium use in those patients.MethodsSystematic review of retrospective investigations in PubMed and Medline was performed in July 2016. Primary outcomes included the presence of increased signal intensity within the dentate nucleus and globus pallidus on unenhanced T1-weighted MR images in patients following administrations of GBCAs. Two independent reviewers were responsible for search and data extraction.Results25 publications satisfied inclusion criteria (19 magnetic resonance images analyses, 3 case reports; 3 autopsy studies). Magnetic resonance images of 1247 patients with increased signal intensity on unenhanced T1-weighted MR images were analyzed as well as tissue specimens from 27 patients. Signal intensity correlated positively with the exposure to GBCAs and was greater after serial administrations of linear nonionic than cyclic contrast agents. Gadolinium was detected in all tissue examinations.ConclusionsHigh signal intensity in the dentate nucleus and globus pallidus on unenhanced T1-weighted magnetic resonance images were associated with previous administration of GBCAs. Signal intensity correlated negatively with stability of contrast agents. Clinical significance of gadolinium deposition in the brain remains unclear. There is a strong need for further research to identify type of gadolinium deposited in the brain as well as to gather knowledge about long-term consequences.

Gadolinium-based contrast agents: A comprehensive risk assessment.

1 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:338-353.

No Signal Intensity Increase in the Dentate Nucleus on Unenhanced T1-weighted MR Images after More than 20 Serial Injections of Macrocyclic Gadolinium-based Contrast Agents

Purpose To determine the effect of more than 20 serial injections of macrocyclic gadolinium-based contrast agents (GBCAs) on the signal intensity (SI) of the dentate nucleus (DN) on unenhanced T1-weighted magnetic resonance (MR) images. Materials and Methods In this retrospective, institutional review board-approved study, 33 patients who underwent at least 20 consecutive MR imaging examinations (plus an additional MR imaging for reference) with the exclusive use of macrocyclic GBCAs gadoterate meglumine and gadobutrol were analyzed. SI ratio differences were calculated for DN-to-pons and DN-to-middle cerebellar peduncle (MCP) ratios by subtracting the SI ratio at the first MR imaging examination from the SI ratio at the last MR imaging examination. One-sample t tests were used to examine if the SI ratio differences differed from 0, and Bayes factors were calculated to quantify the strength of evidence for each test. Results Patients underwent a mean of 23.03 ± (standard deviation) 4.20 GBCA administrations (mean accumulated dose, 491.21 mL ± 87.04 of a 0.5 M GBCA solution) with an average of 12.09 weeks ± 2.16 between every administration. Both ratio differences did not differ significantly from 0 (DN-to-pons ratio: -0.0032 ± 0.0154, P = .248; DN-to-MCP ratio: -0.0011 ± 0.0093, P = .521), and one-sided Bayes factors provided substantial to strong evidence against an SI ratio increase (Bayes factor for DN-to-pons ratio = 0.09 and that for DN-to-MCP ratio = 0.12). Conclusion The study indicates that 20 or more serial injections of macrocyclic GBCAs administered with on average 3 months between each injection are not associated with an SI increase in the DN. © RSNA, 2016.

Do Gadolinium-Based Contrast Agents Affect 18F-FDG PET/CT Uptake in the Dentate Nucleus and the Globus Pallidus? A Pilot Study.

Gadolinium is toxic and to avoid its deposition in tissues, it must be chemically bonded with nonmetal ions to facilitate its excretion by the kidneys. High signal intensity in the dentate nucleus (DN) and globus pallidus (GP) on unenhanced T1-weighted MR images has been both morphologically and pathologically linked to gadolinium-based contrast agent (GBCA) retention in the brain. The purpose of this study was to determine whether repeated administrations of GBCA would affect the uptake of 18F-FDG in the DN and GP on PET/CT. Methods: Three hundred seventy-six patients who underwent both contrast-enhanced MR (CE MR) of the brain and PET/CT from January 2004 to October 2015 were identified. Patients with a history of brain irradiation or hepatic or renal disease were excluded. The SUVmax was measured in the DN and GP on the PET/CT scan in patients who had 3-6 successive CE MR brain studies. The SUVmax of the corresponding areas in the control group of patients who had not undergone previous CE MR and who had a normal, unenhanced MR finding of the brain was also measured. A Wilcoxon 2-sample test was used for statistical analysis. Results: Fifteen of 376 (4%) patients (mean age ± SD, 54 ± 18 y; 10 men and 5 women) were included in the subject group, and 15 patients (mean age ± SD, 36 ± 9 y; 11 men and 4 women) were included in the control group. The median DN SUVmax was significantly lower in the subject group than in the control group (5.4 vs. 6.4, respectively; P = 0.021). Similarly, the median GP SUVmax was significantly lower in the subject group than in the control group (8.8 vs. 12.1, respectively; P = 0.003). Conclusion: The median SUVmax in the DN and GP was 16% and 27% lower, respectively, in patients who received GBCAs than in those who had not received GBCAs, possibly related to gadolinium deposition in these areas.

Effect of Renal Function on Gadolinium-Related Signal Increases on Unenhanced T1-Weighted Brain Magnetic Resonance Imaging.

The purpose of this study was to determine if renal function affects signal changes in the deep brain nuclei on unenhanced T1-weighted images after administration of linear gadolinium-based contrast agents (GBCAs). An electronic medical records search of 2 large medical centers identified 25 patients who received linear GBCA while on hemodialysis and had unenhanced T1-weighted images of the brain before and after. The dentate-to-cerebellar peduncle (DCP) ratio, globus pallidus-to-mid thalamus (GPT) ratio, and choroid plexus-to-nearby white matter ratio were measured and compared with 25 age/sex/GBCA exposure-matched control patients with normal or near-normal renal function (estimated glomerular filtration rate >60 mL/min per 1.73 m). Two additional control groups included 13 patients on hemodialysis without GBCA exposure and 13 age/sex-matched patients with estimated glomerular filtration rate greater than 60 mL/min per 1.73 m. Hemodialysis patients (n = 25) with an average of 1.8 linear GBCA administrations had a 4.9% mean increase (1.00 ± 0.04 vs 1.05 ± 0.05; P < 0.001) in DCP, which was greater than the 1.6% change (0.99 ± 0.04 vs 1.00 ± 0.05; P = 0.08) observed in matched controls (P = 0.01). There was no significant signal change in the DCP ratio in the 13 hemodialysis patients (0.99 ± 0.04 vs 0.99 ± 0.04; P = 0.78) and 13 age/sex-matched patients (0.99 ± 0.02 vs 0.99 ± 0.03; P = 0.78) who did not receive GBCA. The hemodialysis patients had a baseline GPT that was higher than nondialysis patients (P < 0.001). However, the GPT change after GBCA administration was not significantly different from controls. Increased signal in the choroid plexus on unenhanced T1-weighted images after GBCA administration was noted in hemodialysis patients (0.72 ± 0.20 vs 0.86 ± 0.23; P = 0.006); however, a multivariate analysis showed this to be primarily related to hemodialysis (P = 0.003) with only a trend toward relating to GBCA exposure (P = 0.07). Hemodialysis patients receiving linear GBCA have greater dentate nucleus signal increases on unenhanced T1-weighted images, suggesting that renal function may affect the rate of gadolinium accumulation in the brain after linear GBCA-enhanced magnetic resonance imaging.

Global and Regional Brain Assessment with Quantitative MR Imaging in Patients with Prior Exposure to Linear Gadolinium-based Contrast Agents.

Purpose To assess the association of global and regional brain relaxation times in patients with prior exposure to linear gadolinium-based contrast agents (GBCAs). Materials and Methods The institutional review board approved this cross-sectional study. Thirty-five patients (nine who had received GBCA gadopentetate dimeglumine injections previously [one to eight times] and 26 patients who did not) who underwent brain magnetic resonance (MR) imaging with a mixed fast spin-echo pulse sequence were assessed. The whole brain was segmented according to white and gray matter by using a dual-clustering algorithm. In addition, regions of interest were measured in the globus pallidus, dentate nucleus, thalamus, and pons. The Mann-Whitney U test was used to assess the difference between groups. Multiple regression analysis was performed to assess the association of T1 and T2 with prior GBCA exposure. Results T1 values of gray matter were significantly shorter for patients with than for patients without prior GBCA exposure (P = .022). T1 of the gray matter of the whole brain (P < .001), globus pallidus (P = .002), dentate nucleus (P = .046), and thalamus (P = .026) and T2 of the whole brain (P = .004), dentate nucleus (P = .023), and thalamus (P = .002) showed a significant correlation with the accumulated dose of previous GBCA administration. There was no significant correlation between T1 and the accumulated dose of previous GBCA injections in the white matter (P = .187). Conclusion Global and regional quantitative assessments of T1 and T2 demonstrated an association with prior GBCA exposure, especially for gray matter structures. The results of this study confirm previous research findings that there is gadolinium deposition in wider distribution throughout the brain. © RSNA, 2016 Online supplemental material is available for this article.

T1 hyperintensity on brain imaging subsequent to gadolinium-based contrast agent administration: what do we know about intracranial gadolinium deposition?

There is growing evidence for the accumulation of gadolinium (Gd) in patients administered with intravenous Gd-based contrast agents, even in the absence of renal impairment. This review of the literature will discuss what has been found to date in cadaveric human studies, clinical studies of patients and from animal models. Evidence for the potential route of entry into the brain will be examined. The current state of knowledge of effects of Gd accumulation in the brain is discussed. We will then discuss what the possible implications may be for the choice of Gd-based contrast agents in clinical practice.

Biparametric 3T Magentic Resonance Imaging for prostatic cancer detection in a biopsy-naïve patient population: a further improvement of PI-RADS v2?

ObjectivesTo prospectively determine the diagnostic accuracy of a biparametric 3T magnetic resonance imaging protocol (BP-MRI) for prostatic cancer detection, compared to a multiparametric MRI protocol (MP-MRI), in a biopsy naïve patient population. MethodsEighty-two untreated patients (mean age 65±7.6years) with clinical suspicion of prostate cancer and/or altered prostate-specific antigen (PSA) levels underwent a MP-MRI, including T2-weighted imaging, diffusion-weighted imaging (with the correspondent apparent diffusion coefficient maps) and dynamic contrast enhanced sequence, followed by prostate biopsy. Two radiologists reviewed both the BP-MRI and the MP-MRI protocols to establish a radiological diagnosis. Receiver operating characteristics curves were obtained to determine the diagnostic performance of the two protocols. ResultsThe mean PSA level was 8.8±8.1ng/ml. A total of 34 prostatic tumors were identified, with a Gleason score that ranged from 3+3 to 5+4. Of these 34 tumors, 29 were located within the peripheral zone and 5 in the transitional zone. BP-MRI and MP-MRI showed a similar performance in terms of overall diagnostic accuracy, with an area under the curve of 0.91 and 0.93, respectively (p=n.s.). ConclusionsBP-MRI prostate protocol is feasible for prostatic cancer detection compared to a standard MP-MRI protocol, requiring a shorter acquisition and interpretation time, with comparable diagnostic accuracy to the conventional protocol, without the administration of gadolinium-based contrast agent.

Impact of Impaired Renal Function on Gadolinium Retention After Administration of Gadolinium-Based Contrast Agents in a Mouse Model.

The aim of this study was to investigate the impact of impaired renal function on gadolinium (Gd) retention in various organs after Gd-based contrast agent injection. After local animal care and review committee approval, 23 normal mice and 26 with renal failure were divided into 4 treatment groups (Gd-DTPA-BMA, 5 mmol/kg; Gd-DOTA, 5 mmol/kg; GdCl3, 0.02 mmol/kg; and saline, 250 μL). Each agent was intravenously administered on weekdays for 4 weeks. Samples were collected on days 3 (short-term) and 45 (long-term) after the last injection. Gadolinium concentrations were quantified by inductively coupled plasma-mass spectrometry. Three mice with renal failure and 2 normal mice in the GdCl3 group and 1 mouse with renal failure in the Gd-DTPA-BMA group died. In the Gd-DTPA-BMA group, impaired renal function increased short-term Gd retention in the liver, bone, spleen, skin, and kidney (P < 0.01) but did not affect long-term Gd retention. Gd-DTPA-BMA showed higher Gd retention than Gd-DOTA. Although Gd retention in the Gd-DOTA group was generally low, impaired renal function increased only long-term hepatic Gd retention. Hepatic and splenic Gd retentions were significantly higher than other organs' Gd retention in the GdCl3 group (P < 0.01). Renal function did not affect brain Gd retention, regardless of the Gd compound used. The tendency of Gd retention varied according to the agent, regardless of renal function. Although renal impairment increased short-term Gd retention after Gd-DTPA-BMA administration, long-term Gd retention for Gd-based contrast agents was almost unaffected by renal function, suggesting that the chemical structures of retained Gd may not be consistent and some Gd is slowly eliminated after initially being retained.

Potential Safety Issues Related to the Use of Gadolinium-based Contrast Agents.

This article reviews recent research on gadolinium deposit formation in the brain linked to contrast-enhanced MRI studies. Human and animal studies have confirmed the presence of gadolinium in the brain following the serial administration of gadolinium-based contrast agents. This is a relatively new and growing field of research primarily driven by concerns regarding unknown and potentially harmful side effects of gadolinium-based contrast agents. Retrospective observational in vivo studies in humans demonstrated T1 shortening effects in the brain parenchyma resulting from gadolinium exposure. These studies were followed by postmortem human and animal studies. Evidence exists that gadolinium may cause deposits in the brain and that this may occur independently of impaired renal function and in the presence of an intact blood-brain barrier. Gadolinium deposition has been linked primarily with the use of linear, rather than macrocyclic, gadolinium-based contrast agents. The formation of gadolinium deposits and its implications have been the focus of only a small number of research groups. The currently available data must be verified, and the potential factors that may be linked to this phenomenon and the clinical significance must be explored. Depending on future findings, changes in the clinical application of gadolinium-based contrast agents may be expected.