Prognostic Value of Feature-Tracking Circumferential Strain in Dilated Cardiomyopathy Patients with Severely Reduced Ejection Fraction Incremental to Late Gadolinium Enhancement.

Myocardial fiber deformation measurements have been reported to be associated with adverse outcomes in patients with acute heart failure and those with myocardial infarction. However, few studies have addressed the prognostic value of global circumferential strain (GCS) in dilated cardiomyopathy (DCM) patients with severely impaired systolic function. This study aimed to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived GCS in DCM patients with severely reduced ejection. Consecutive DCM patients with severely reduced ejection fraction (EF <35%) who underwent CMR were included. GCS was calculated from CMR cine images. The clinical endpoint was a composite of all-cause mortality, heart transplantation, implantable cardioverter defibrillator (ICD) implantation and aborted sudden cardiac death (SCD). A total of 129 patients with a mean EF of 15.33% (11.36%-22.27%) were included. During a median follow-up of 518 days, endpoint events occurred in 50 patients. Patients with GCS ≥ the median (-5.17%) had significantly reduced event-free survival as compared with those with GCS < the median (P<0.01). GCS was independently associated with adverse events after adjusting for clinical and imaging risk factors including extent of late gadolinium enhancement (LGE) (P<0.05). Adding GCS into the model including the extent of LGE resulted in significant improvements in the C-statistic (from 0.706 to 0.742; P<0.05) with a continuous net reclassification improvement (NRI) of 29.71%. It was concluded that GCS derived from CMR could be useful for risk stratification in DCM patients with severely reduced EF, which may increase common imaging risk factors including LGE.

Use and Safety of Gadolinium Based Contrast Agents in Pediatric MR Imaging.

Gadolinium-based contrast agents (GBCA) used for MR imaging are a valuable imaging resource that has benefited patient management over last three decades and largely have a high safety profile. However, recently, adverse effects related to GBCA like nephrogenic systemic fibrosis (NSF) and asymptomatic gadolinium deposition in tissues including brain are concerning. While NSF has largely stopped occurring due to precautions and guidelines to not use GBCA in patients with poor renal function, the long term effects of gadolinium deposition, especially in brain, are not known at this stage. Cautious approach needs to be taken with risk-benefit analysis in each patient to avoid its administration when not necessary. In this review, authors discuss basics of gadolinium, mechanism of enhancement, agents in clinical use and safety issues, and in the end, offer some solutions for safety concerns.

Recommended administered activities for (68)Ga-labelled peptides in paediatric nuclear medicine.

PURPOSE: The aim of this study was to establish a method for determining administered activities for (68)Ga-labelled peptides. Dose calculations were based on the weight-independent effective dose model proposed by the EANM paediatric dosage card for use in paediatric nuclear medicine. METHODS: Previously published time-integrated activity coefficients for (68)Ga-DOTATATE, (68)Ga-DOTATOC and (68)Ga-pentixafor were used to calculate age-independent effective doses. Consequently, the corresponding weight-dependent effective dose coefficients were rescaled according to the formalism of the EANM dosage card to determine the radiopharmaceutical class of  (68)Ga-labelled peptides ("multiples") and to calculate the baseline activities based on an upper limit for administered activity (185 MBq) in an adult. RESULTS: All calculated normalization factors suggest that the (68)Ga-labelled peptides are class "B" radiopharmaceuticals. The baseline activity for all compounds is 12.8 MBq. In analogy to (18)F-fluoride, we recommend a minimum activity of 14 MBq. CONCLUSION: For paediatric nuclear medicine applications involving (68)Ga-labelled peptides, we suggest determining administered activities based on the formalism proposed in this work. The corresponding effective doses from these procedures will remain age-independent.

A non-aqueous reduction process for purifying ¹5³Gd produced in natural europium targets.

Gadolinium-153 is a low-energy gamma-emitter used in nuclear medicine imaging quality assurance. Produced in nuclear reactors using natural Eu2O3 targets, ¹5³Gd is radiochemically separated from europium isotopes by europium reduction. However, conventional aqueous europium reduction produces hydrogen gas, a flammability hazard in radiological hot cells. We altered the traditional reduction method, using methanol as the process solvent to nearly eliminate hydrogen gas production. This new, non-aqueous reduction process demonstrates greater than 98% europium removal and gadolinium yields of 90%.

Gadolinium in pediatric cardiovascular magnetic resonance: what we know and how we practice.

BACKGROUND: The association of gadolinium-based contrast agents (GBCAs) with nephrogenic systemic fibrosis (NSF) has led to a heightened awareness towards patients' renal function. Whereas detailed guidelines exist for the use of GBCAs in adult patients, best practice is less well defined in children, especially in the very young. We aimed at identifying current practice with regards to the use of GBCAs in children who undergo cardiovascular magnetic resonance. METHODS: We conducted a worldwide survey among cardiac imagers with pediatric expertise. The questionnaire contained 21 questions covering the imagers' work environments, GBCAs used, monitoring of renal function, and a special emphasis was placed on the practice in neonates. RESULTS: The survey yielded 70 replies. The single most commonly used GBCA was gadopentetate dimeglumine 34/70 (49%). Among the respondents, the choice of GBCA was more importantly based on availability 26/70 (37%) and approval by a pharmaceutical licensing body that most closely reflects the indication 16/70 (23%) than image quality 7/70 (10%) and side effect profile 8/70 (11%). 55/70 (79%) of respondents performed scans in neonates <1 week of age and 52/55 (95%) of them used GBCA in neonates. 65/70 (93%) respondents at least assess some of their patients' renal functions. Formula-based estimate of glomerular filtration rate is the most popular assessment method 35/65 (54%). In patients with a glomerular filtration rate < 30 ml/min/1.73 m(2) 62/70 (89%) of respondents do not administer gadolinium at all. The single most common side effect of gadolinium was noted to be nausea/emesis 34/57 (60%) followed by discomfort at injection site 17/57 (30%). CONCLUSIONS: Cardiac imagers are aware of the immature renal function and physiological differences of their pediatric patients that place them at risk for NSF. Epidemiological data is needed for pediatric cardiovascular licensure of gadolinium compounds and for the creation of practice guidelines which will replace current-day practice based on individual clinical judgment.

Gadolinium-enhanced cardiovascular magnetic resonance: administered dose in relationship to United States Food and Drug Administration (FDA) guidelines.

PURPOSE: Myocardial late gadolinium enhancement was originally validated using higher than label-recommended doses of gadolinium chelate. The objective of this study was to evaluate available evidence for various gadolinium dosing regimens used for CMR. The relationship of gadolinium dose warnings (due to nephrogenic systemic fibrosis) announced in 2008 to gadolinium dosing regimens was also examined. METHODS: We conducted a meta-analysis of peer reviewed publications from January, 2004 to December, 2010. Major subject search headings (MeSh) terms from the National Library of Medicine's PubMed were: contrast media, gadolinium, heart, magnetic resonance imaging; searches were limited to human studies with abstracts published in English. Case reports, review articles, editorials, MRA related papers and all reports that did not indicate gadolinium type or weight-based dose were excluded. For all included references, full text was available to determine the total administered gadolinium dose on a per kg basis. Average and median dose values were weighted by the number of subjects in each study. RESULTS: 399 publications were identified in PubMed; 233 studies matched the inclusion criteria, encompassing 19,934 patients with mean age 54.2 ± 11.4 (range 9.3 to 76 years). 34 trials were related to perfusion testing and 199 to myocardial late gadolinium enhancement. In 2004, the weighted-median and weighted-mean contrast dose were 0.15 and 0.16 ± 0.06 mmol/kg, respectively. Median contrast doses for 2005-2010 were: 0.2 mmol/kg for all years, respectively. Mean contrast doses for the years 2005-2010 were: 0.19 ± 0.03, 0.18 ± 0.04, 0.18 ± 0.10, 0.18 ± 0.03, 0.18 ± 0.04 and 0.18 ± 0.04 mmol/kg, respectively (p for trend, NS). Gadopentetate dimeglumine was the most frequent gadolinium type [114 (48.9%) studies]. No change in mean gadolinium dose was present before, versus after the Food and Drug Administration (FDA) black box warning (p > 0.05). Three multi-center dose ranging trials have been published for cardiac MRI applications. CONCLUSION: CMR studies in the peer-reviewed published literature routinely use higher gadolinium doses than regulatory agencies indicated in the package leaflet. Clinical trials should be supported to determine the appropriate doses of gadolinium for CMR studies.

Gadolinium contrast agents: their role in vascular and nonvascular diagnostic angiography and interventions.

Gadolinium-based contrast agents can be used for diagnostic and interventional angiographic procedures to reduce contrast-related nephrotoxicity or in patients with a history of severe allergic reaction to iodine-containing contrast material. These agents are best used in conjunction with CO(2) to complete nondiagnostic CO(2) angiograms and to monitor the progress of a percutaneous intervention. However, the total volume of gadolinium that can be administered, the reduced quality of gadolinium digital subtraction angiography images, and the increased cost of the gadolinium-based agents can limit their use.