Good MRI images: to Gad or not to Gad?

Bioinspired nanoreactors for the biomineralisation of metallic-based nanoparticles for nanomedicine

This review explores the synthesis of inorganic metallic-based nanoparticles (MBNPs) (metals, alloys, metal oxides) using biological and biologically inspired nanoreactors for precipitation/crystallisation. Such nanoparticles exhibit a range of nanoscale properties such as surface plasmon resonance (nobel metals e.g. Au), fluorescence (semiconductor quantum dots e.g. CdSe) and nanomagnetism (magnetic alloys e.g. CoPt and iron oxides e.g. magnetite), which are currently the subject of intensive research for their applicability in diagnostic and therapeutic nanomedicine. For such applications, MBNPs are required to be biocompatible, of a precise size and shape for a consistent signal or output and be easily modified with biomolecules for applications. Ideally the MBNPs would be obtained via an environmentally-friendly synthetic route. A biological or biologically inspired nanoreactor synthesis of MBNPs is shown to address these issues. Biological nanoreactors for crystallizing MBNPs within cells (magnetosomes), protein cages (ferritin) and virus capsids (cowpea chlorotic mottle, cowpea mosaic and tobacco mosaic viruses), are discussed along with how these have been modified for applications and for the next generation of new materials. Biomimetic liposome, polymersome and even designed self-assembled proteinosome nanoreactors are also reviewed for MBNP crystallisation and further modification for applications. With the advent of synthetic biology, the research and understanding in this field is growing, with the goal of realising nanoreactor synthesis of MBNPs for biomedical applications within our grasp in the near future.

Safety first: Recognizing and managing the risks to child participants in magnetic resonance imaging research

Specialized and up-to-date knowledge is required to identify and manage the risks associated with advanced biomedical research. Additional complexities need to be considered when the research involves infants or young children. In this article, we focus on recent information about the physical risks of pediatric magnetic resonance imaging research and highlight information gaps. With an eye to assisting institutional review boards and researchers, we consider strategies for the management of these risks and formulate key questions aimed at exposing hidden hazards. Institutional review boards should ask these questions, and researchers should bear them in mind as they develop research protocols.

Renal transplantation in children with thrombosis of the inferior vena cava requires careful assessment and planning

Children with end-stage renal disease and inferior vena cava (IVC) thrombosis are rare, and their condition is complex and high risk for renal transplantation. Detailed imaging studies of the recipient's abdominal vasculature should be carried out prior to transplantation, followed by careful pre-operative joint planning by the pediatric transplant surgeon and nephrologist. Critical decisions need to be made as to whether a deceased child's kidney or an adult-sized kidney is to be used, and if the latter, whether it should be from a deceased or living donor. In addition, the contemplated site of the donor's renal vein anastomosis needs to be determined with a consideration of the possible consequences of the various choices. Sixteen cases of renal transplantation in children with pre-existing IVC thrombosis are reviewed, including the three reported by Shenoy et al. in this journal. With a full understanding of the difficulties noted, renal transplantation in a small child with IVC thrombosis can be successful. However, it requires thorough recipient assessment, coupled with a careful and thoughtful examination of options, to determine the best possible approach to the transplantation.

Nephrogenic systemic fibrosis and the use of gadolinium-based contrast agents

Nephrogenic systemic fibrosis (NSF) is a disease seen exclusively in patients with decreased renal function. The use of gadolinium-based contrast agents (GBCAs) has a strong association with NSF. Linear non-ionic GBCAs that are more prone to release free gadolinium are the more likely to cause NSF. The number of reported cases has increased recently, and there are currently nine pediatric cases, the patients ranging in age from 8 years to 19 years, and the oldest adult patient is 87 years of age. The most successful treatment is improvement of renal function with renal transplantation or with recovery of acute kidney injury. NSF can be severely debilitating and even fatal. Avoidance of a GBCA in patients at risk, or limitation of the dose in the patients who need gadolinium enhancement, is recommended.

Potential risks in radiology departments

Pediatric patients in the Emergency Department (ED) often need diagnostic imaging examinations. These range from radiographs to fluoroscopic procedures to CT and MRI. Each of these examinations requires transportation and hand-offs (transfer of patient to different health care workers), and each carries inherent risks of the procedure itself. The following material will examine a variety of common situations that involve interaction between patients from the ED and the radiology department and describe potential risks and methods through which these risks can be minimized.

Idiopathic mid-aortic syndrome in children

Mid-aortic syndrome (MAS) is an uncommon condition characterized by narrowing of the abdominal aorta and stenosis of its major branches. Our goal was to illustrate the presentation, diagnosis and management of six new cases of idiopathic MAS together with 96 cases of idiopathic MAS from the literature. The mean age of the 102 cases was 14.3 years (19 days to 49 years). Our patient who presented at 19 days of age is the youngest reported to date. Clinical presentations included hypertension (94%), claudication (17%), renal failure (4%) and intestinal ischemia (1%). Angiography was the diagnostic imaging study of choice. Renal arteries were involved in 91% of patients, while the superior mesenteric artery and celiac artery were involved in 35%. Thirteen percent of cases were managed medically, and the remainder was treated surgically. Our experience shows that initial conservative blood pressure management of idiopathic MAS is feasible unless medical control of hypertension is unsatisfactory, renal function is at risk or there are symptoms of claudication or intestinal ischemia. Careful timing and planning of a surgical intervention is possible for most cases and may, in select cases, be considered after completion of puberty to allow growth to be completed.