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There has been an increase in the number of units providing anaesthesia for magnetic resonance imaging and the strength of magnetic resonance scanners, as well as the number of interventions and operations performed within the magnetic resonance environment. More devices and implants are now magnetic resonance imaging conditional, allowing scans to be undertaken in patients for whom this was previously not possible. There has also been a revision in terminology relating to magnetic resonance safety of devices. These guidelines have been put together by organisations who are involved in the pathways for patients needing magnetic resonance imaging. They reinforce the safety aspects of providing anaesthesia in the magnetic resonance environment, from the multidisciplinary decision making process, the seniority of anaesthetist accompanying the patient, to training in the recognition of hazards of anaesthesia in the magnetic resonance environment. For many anaesthetists this is an unfamiliar site to give anaesthesia, often in a remote site. Hospitals should develop and audit governance procedures to ensure that anaesthetists of all grades are competent to deliver anaesthesia safely in this area.

The number of anaesthetists who are involved in magnetic resonance (MR) units is increasing. Magnetic resonance systems are becoming more powerful and interventional procedures are now possible. This paper updates information relating to safety terminology, occupational exposure, reactions to gadolinium-based contrast agents and the risk of nephrogenic systemic fibrosis. Magnetic resonance examinations of patients with pacemakers are still generally contra-indicated but have been carried out in specialist centres under strictly controlled conditions. As availability of MR increases, so the education of anaesthetists, who are occasionally required to provide a service, must be considered. Anaesthesia in MR units was first described in the 1980s. Guidelines on the provision of anaesthetic services in MR units were published by the Association of Anaesthetists of Great Britain and Ireland (AAGBI) in 2002 [1]. Since then, the number of hospitals with MR units, and hence the number of patients requiring anaesthesia for MR, has increased. While the issues relating to setting up anaesthetic services in MR have not changed, there have been a number of developments that warrant this update: Safety terminology and guidelines have changed. MR systems utilise higher magnetic-field strengths and more open designs are available. Interventional and intra-operative MR are now routine in some centres. Mobile MR scanners are increasingly used to reduce waiting lists. Although still generally contra-indicated, some patients with pacemakers have been scanned under strictly controlled conditions in specialist centres. ‘MR safe’ medical implants are now being produced. New equipment is now available for use in MR. Out-of-hours availability of MR investigations has increased. Reports of allergic reactions to MR contrast media have increased. Gadolinium based contrast agents (Gd-CAs) are associated with a varying degree of risk of nephrogenic systemic fibrosis in patients with impaired renal function. Safety guidelines and legislation In 2007 the Medicines and Healthcare products Regulatory Agency (MHRA) updated safety guidance as a Device Bulletin [2]. Three terms are now to be used as standard in an attempt to remove any ambiguity caused by the old MR compatible system. These terms are MR conditional, MR safe and MR unsafe. MR conditional refers to an item that has been demonstrated to pose no known hazards in a specified MR environment with specified conditions of use. Many items in the MR environment will now be marked as MR conditional, and the conditions under which they can be safely used must accompany the device. This change of terminology has come about because of reports of injuries and problems with MR compatible equipment [3]. Conditions that define the specified MR environment include main magnetic field strength, spatial magnetic field gradient, dB/dt (time rate of change of the magnetic field), radio frequency (RF) field strength, and specific absorption rate. Additional conditions, including specific configurations of the item of equipment, may be required. Equipment is designated as MR safe if it presents no safety hazard to patients or personnel when it is taken into the MR examination room, provided that instructions concerning its use are correctly followed. This does not, however, guarantee that it will function normally and not interfere with the correct operation of the MR imaging equipment, with degradation of image quality. New equipment, such as infusion pumps [4], warming mattresses and temperature probes are now available. It is important to understand the manufacturers’ instructions of all equipment that is brought into the vicinity of the MR scanner. It should be recognised that the supervising MR radiographer is responsible operationally for MR safety within the controlled area and that anaesthetic staff should defer to him/her in relation to MR safety matters, in particular control of access of staff and equipment into the controlled area. Where staff are given access codes or swipe-card access to the controlled area, they should not be shared with others, nor should they provide access to others unless specifically authorised to do so. Inspired oxygen concentration The use of 100% O2 during anaesthesia should be reported to the reporting radiologist as this can produce an artefact in the form of an abnormally high signal in cerebrospinal fluid (CSF) spaces in the T2 weighted fluid attenuated inversion recovery (FLAIR) sequence.

Subarachnoid haemorrhage is a common neurological emergency, which carries a high morbidity and mortality. It is usually caused by rupture of an intracerebral aneurysm or, less commonly, an arteriovenous malformation. Although most patients present to a non-neurosurgical hospital, they often require urgent neurosurgical or neuroradiological intervention. Whilst awaiting transfer to a neurological centre, active management of the patient must be instituted. This should include confirmation of the diagnosis with CT imaging, lumbar puncture or both, and recognition of the complications of subarachnoid haemorrhage, which include hydrocephalus, further haemorrhage and cerebral vasospasm. Medical management is directed towards maintaining adequate cerebral perfusion pressure whilst avoiding large increases in arterial blood pressure. Nimodipine therapy must be started early in an attempt to prevent cerebral vasospasm. The treatment options available at the neurological centre include surgical treatment or endovascular obliteration of the aneurysm or arteriovenous malformation.

The structure of the 10-I-4 periodonium ion of bis[α,α-bis(trifluoromethyl)benzenemethanolato(2-)-C 2 , O α ]iodine (1+) triflate, salt 1a, was confirmed by an X-ray crystallographic structure determination. The periodonium ion of 1a was the first example of a stable cationic 10-I-4 species lacking fluorine ligands. In contrast to other periodonium ions, that of 1a is not hydrolyzed by atmospheric moisture nor by water in neutral or acidic media. It does not react with weak nucleophiles such as pyridine or methanol.The lack of reactivity of the periodonium ion of 1a is better rationalized by comparision with other spirobicyclic 10-X-4 systems than with other known 12-I-5 or 10-I-4 species.Stricking parallels between the structures and properties of 10-X-4 species with identical bidentate ligands support the idea that properties of isovalent and isostructural hypervalent 10-X-4 species are predictable on the basis of ligand properties.Indeed the most stricking aspect of the reactivity of the periodonium ion of 1a is how little it resembles the reactivity of other the reactivity of other known iodine species in the same oxidation state.This is direct result of the specific geometry and electron distribution imposed on the central atom of a 10-X-4 species by the spirobicyclic ligand system, which was designed for specific stabilizing features for Ψ-TBP and TBP 10-X-L systems

An approach is outlined for the analysis of nonrandom allelic associations in multilocus systems in a diploid population. The concept of composite link functions in generalised linear model analysis is used to handle the problem of incomplete identification of constituent gametes often encountered in genotypic data for two or more marker loci.

Beckmann rearrangement of alkylcyclooctenone oximes VIa and VIb gave corresponding nine-membered lactams 1,3,4,5,8,9-hexahydro-3-methyl-2H-azonin-2-one (VIIIa) and 1,3,4,5,8,9-hexahydro-3-butyl-2H-azonin-2-one (VIIIb), respectively. A stereospecific transannular cyclization was induced by mercuric acetate leading to alkyl indolizinones Xa and Xb. Temperature and solvent dependent nmr spectra of the medium ring lactams indicates the stereochemical control is caused by steric interactions of the alkyl side chain. Lithium aluminum hydride reduced Xa/Xb to cis-octahydro-6-methylindolizidine (XIa) and cis-octahydro-3-n-butylindolizidine (XIb).