Imaging manifestations of IgG4-related disease.

IgG4-related disease is a multisystem immune-mediated disorder associated with lesions manifesting an IgG4-rich plasma cell infiltrate and often raised serum IgG4 concentrations. The disease can mimic neoplastic, infective, and inflammatory processes due to features such as development of masses or organ enlargement. Prompt consideration of this diagnosis is essential to avoid unnecessary investigations and offer appropriate treatments, which can include steroids and other immunosuppressive agents. Although histology is typically diagnostic, imaging is critical to assess disease burden, determine biopsy targets, and evaluate response to treatment. Characteristic imaging features can also point towards the diagnosis in the absence of biopsy. This review highlights these features, as well as more atypical findings, grouped by organ or system. Differential diagnoses are emphasised. The full spectrum of imaging methods is discussed. Whole-body imaging with integrated 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) has an evolving role in the detection of multi-organ involvement and subsequent follow-up.

Development and large volume production of extremely high current density YBa2Cu3O7 superconducting wires for fusion.

The fusion power density produced in a tokamak is proportional to its magnetic field strength to the fourth power. Second-generation high temperature superconductor (2G HTS) wires demonstrate remarkable engineering current density (averaged over the full wire), JE, at very high magnetic fields, driving progress in fusion and other applications. The key challenge for HTS wires has been to offer an acceptable combination of high and consistent superconducting performance in high magnetic fields, high volume supply, and low price. Here we report a very high and reproducible JE in practical HTS wires based on a simple YBa2Cu3O7 (YBCO) superconductor formulation with Y2O3 nanoparticles, which have been delivered in just nine months to a commercial fusion customer in the largest-volume order the HTS industry has seen to date. We demonstrate a novel YBCO superconductor formulation without the c-axis correlated nano-columnar defects that are widely believed to be prerequisite for high in-field performance. The simplicity of this new formulation allows robust and scalable manufacturing, providing, for the first time, large volumes of consistently high performance wire, and the economies of scale necessary to lower HTS wire prices to a level acceptable for fusion and ultimately for the widespread commercial adoption of HTS.

p-wave superconductivity in iron-based superconductors.

The possibility of p-wave pairing in superconductors has been proposed more than five decades ago, but has not yet been convincingly demonstrated. One difficulty is that some p-wave states are thermodynamically indistinguishable from s-wave, while others are very similar to d-wave states. Here we studied the self-field critical current of NdFeAs(O,F) thin films in order to extract absolute values of the London penetration depth, the superconducting energy gap, and the relative jump in specific heat at the superconducting transition temperature, and find that all the deduced physical parameters strongly indicate that NdFeAs(O,F) is a bulk p-wave superconductor. Further investigation revealed that single atomic layer FeSe also shows p-wave pairing. In an attempt to generalize these findings, we re-examined the whole inventory of superfluid density measurements in iron-based superconductors and show quite generally that single-band weak-coupling p-wave superconductivity is exhibited in iron-based superconductors.

The onset of dissipation in high-temperature superconductors: magnetic hysteresis and field dependence.

Recently, we showed that the self-field transport critical current, Ic(sf), of a superconducting wire can be defined in a more fundamental way than the conventional (and arbitrary) electric field criterion, Ec = 1 µV/cm. We defined Ic(sf) as the threshold current, Ic,B, at which the perpendicular component of the local magnetic flux density, B⊥, measured at any point on the surface of a high-temperature superconducting tape abruptly crosses over from a non-linear to a linear dependence with increasing transport current. This effect results from the current distribution across the tape width progressively transitioning from non-uniform to uniform. The completion of this progressive transition was found to be singular. It coincides with the first discernible onset of dissipation and immediately precedes the formation of a measureable electric field. Here, we show that the same Ic,B definition of critical currents applies in the presence of an external applied magnetic field, Ba. In all experimental data presented here Ic,B is found to be significantly (10-30%) lower than Ic,E determined by the common electric field criterion of Ec = 1 µV/cm, and Ec to be up to 50 times lower at Ic,B than at Ic,E.

Quality assurance in radiology: peer review and peer feedback.

Peer review in radiology means an assessment of the accuracy of a report issued by another radiologist. Inevitably, this involves a judgement opinion from the reviewing radiologist. Peer feedback is the means by which any form of peer review is communicated back to the original author of the report. This article defines terms, discusses the current status, identifies problems, and provides some recommendations as to the way forward, concentrating upon the software requirements for efficient peer review and peer feedback of reported imaging studies. Radiologists undertake routine peer review in their everyday clinical practice, particularly when reporting and preparing for multidisciplinary team meetings. More formal peer review of reported imaging studies has been advocated as a quality assurance measure to promote good clinical practice. It is also a way of assessing the competency of reporting radiologists referred for investigation to bodies such as the General Medical Council (GMC). The literature shows, firstly, that there is a very wide reported range of discrepancy rates in many studies, which have used a variety of non-comparable methodologies; and secondly, that applying scoring systems in formal peer review is often meaningless, unhelpful, and can even be detrimental. There is currently a lack of electronic peer feedback system software on the market to inform radiologists of any review of their work that has occurred or to provide them with clinical outcome information on cases they have previously reported. Learning opportunities are therefore missed. Radiologists should actively engage with the medical informatics industry to design optimal peer review and feedback software with features to meet their needs. Such a system should be easy to use, be fully integrated with the radiological information and picture archiving systems used clinically, and contain a free-text comment box, without a numerical scoring system. It should form a temporary record that cannot be permanently archived. It must provide automated feedback to the original author. Peer feedback, as part of everyday reporting, should enhance daily learning for radiologists. Software requirements for everyday peer feedback differ from those needed for a formal peer review process, which might only be necessary in the setting of a formal GMC enquiry into a particular radiologist's reporting competence, for example.

A 1 kA-class cryogen-free critical current characterization system for superconducting coated conductors.

A cryogenic electrical transport measurement system is described that is particularly designed to meet the requirements for routine and effective characterization of commercial second generation high-temperature superconducting (HTS) wires in the form of coated conductors based on YBa2Cu3O7. Specific design parameters include a base temperature of 20 K, an applied magnetic field capability of 8 T (provided by a HTS split-coil magnet), and a measurement current capacity approaching 1 kA. The system accommodates samples up to 12 mm in width (the widest conductor size presently commercially available) and 40 mm long, although this is not a limiting size. The sample is able to be rotated freely with respect to the magnetic field direction about an axis parallel to the current flow, producing field angle variations in the standard maximum Lorentz force configuration. The system is completely free of liquid cryogens for both sample cooling and magnet cool-down and operation. Software enables the system to conduct a full characterization of the temperature, magnetic field, and field angle dependence of the critical current of a sample without any user interaction. The system has successfully been used to measure a wide range of experimental and commercially-available superconducting wire samples sourced from different manufacturers across the full range of operating conditions. The system encapsulates significant advances in HTS magnet design and efficient cryogen-free cooling technologies together with the capability for routine and automated high-current electrical transport measurements at cryogenic temperatures. It will be of interest to both research scientists investigating superconductor behavior and commercial wire manufacturers seeking to accurately characterize the performance of their product under all desired operating conditions.

Immediate and sustained benefits of a "total" implementation of speech recognition reporting.

Speech recognition reporting was introduced in our institution to address the significant delay between report dictation and the appearance of a typed report on the Picture Archiving and Communication System (PACS). We report our experience of a "total" implementation of a speech recognition reporting (SRR) system, which became the sole means of radiology reporting from day 1 of introduction. Prospectively gathered Radiology Information System (RIS) data were examined to determine the monthly mean reporting times and completion times for all studies from January 2004 to February 2006 (11 months before introduction of SRR and 15 months after introduction). Studies were grouped for analysis according to referral source (casualty, general practice, inpatient or outpatient). A large, sustained reduction in time to completion was noted in all referral groups at both hospital sites within our institution (6.79 +/- 0.92 days pre-SRR and 2.20 +/- 0.78 days post-SRR, independent two-sample Student's t-test, p<10(-11)). Workflow was maintained following the introduction of SRR: numbers of reports per month and mean times to report were unchanged. SRR eliminated the delays associated with report transcription and subsequent authorisation, dramatically reducing report turnaround times. Resistance to change has perhaps led to suboptimal implementation of SRR in some other institutions, such that benefits have not been fully realised. Our experience demonstrates the dramatic impact that a well-planned, organisation-wide implementation of SRR can have on radiology service delivery.

Peritoneal mesothelioma: an unusual cause of an acute phase response presenting to the rheumatologist.

The presence of an acute phase response may pre-date the eventual diagnosis of malignant disease by months or even years. We describe two patients referred to the rheumatology clinic, in which extensive investigation failed to identify an underlying cause to account for the presenting symptoms and an associated acute phase response. Several months later, repeated abdominal CT scans revealed an abnormality and subsequent laparoscopic biopsy confirmed a diagnosis of peritoneal mesothelioma.

Multidetector CT: what do we do with all the images generated?

Multidetector spiral CT technology generates much more acquisition data than the previous generation of single detector spiral CT machines, and permits more sophisticated and better quality post-processing options, which in turn generate even more imaging data. Such large quantities of data have repercussions upon the mode of image interpretation (hard copy vs soft copy), the speed of data transmission and the storage of these data.

The filmless radiology reading room: a survey of established picture archiving and communication system sites.

The purpose of this study was to survey radiologists experienced in soft-copy diagnosis using computer workstations about their current reading room environment, their impressions of the efficacy of their reading room design, and their recommendations based on their experience for improvement of the soft-copy reading environment. Surveys were obtained from radiologists at seven sites representing three major picture archiving and communication system (PACS) vendors throughout the world that have had extensive experience with soft-copy interpretation of radiology studies. The radiologists filled out a detailed survey, which was designed to assess their current reading room environment and to provide them with the opportunity to make suggestions about improvement of the PACS reading rooms. The survey data were entered into a database and results were correlated with multiple parameters, including experience with PACS, types of modalities interpreted on the system, and number of years of experience in radiology. The factors judged to be most important in promoting radiologist productivity were room lighting, monitor number, and monitor brightness. Almost all of the radiologists indicated that their lighting source was from overhead rather than indirect or portable light sources. Approximately half indicated they had the capability of dimming the brightness of the overhead lighting. Most radiologists indicated that they were able to adjust room temperature but that they did not have individual temperature controls at their workstations. The radiologists indicated that the most troublesome sources of noise included background noise, other radiologists, and clinicians much more than noise from computer monitors, technologists, or patients. Most radiologists did not have chairs that could recline or arm rests. Most did have wheels and the capability to swivel, both of which were judged important. The majority of chairs also had lumbar support, which was also seen to be important. Radiologists commonly adjusted room lighting and their reading chair, but rarely adjusted room temperature or monitor brightness. The median number of hours spent at the workstation before taken a "break" was 1.5. Common recommendations to improve the room layout included compartmentalization of the reading room and availability of the hospital/radiology information system at each workstation. The survey data suggest several areas of potential improvement based on radiologists' experience. Optimization of soft-copy reading room design is likely to result in decreased fatigue and increased productivity.

PACS (picture archiving and communication systems): filmless radiology.

A picture archiving and communication system (PACS) is a computerised means of replacing the roles of conventional radiological film. This review describes the Hammersmith PACS, and discusses the advantages and disadvantages of PACS systems.

Programmable frequency reference for subkilohertz laser stabilization by use of persistent spectral hole burning.

We report what is believed to be the first demonstration of laser frequency stabilization directly to persistent spectral holes in a solid-state material. The frequency reference material was deuterated CaF(2): Tm(3+) prepared with 25-MHz-wide persistent spectral holes on the H(6)(3)?H(4)(3) transition at 798 nm. The beat frequency between two lasers that were independently locked to persistent spectral holes in separate crystal samples showed typical root Allan variances of 780+/-120Hz for 20-50-ms integration times.

[The filmless hospital: 3-year experience at the Hammersmith Hospital, London]. / L'hôpital sans films: expérience de 3 ans à l'Hammersmith hospital de Londres.

A hospital-wide PACS (Picture Archiving and Communication System) is a computerised electronic system which entirely replaces conventional x-ray film by acquiring, archiving, transmitting and displaying digital images on a network of workstations throughout the hospital. Such a system has been operating without film for 3 years now at Hammersmith Hospital, London. PACS has a number of advantages over conventional films. These include time savings, reliability of the system, space savings, economies in consumables and personnel, reduced patient irradiation, efficiency of data management, accessibility of images and teaching benefits. The disadvantages of PACS are: its cost, the need for specialised personnel for its installation and maintenance, training of users, the possibility of breakdown, and data security issues. PACS has altered the work patterns of all its users, including non-radiologist clinicians, radiologists and radiographers. PACS is a step on the way to achieving the future objectives of teleradiology and the complete electronic patient record.

Can PACS make a radiology department more competitive?

One of the motives for putting in a picture archiving and communication system (PACS) is to improve efficiency and hence enhance the competitive strength of the radiology department. Many would argue that it is now negligent to consider installing an old fashioned conventional radiology department rather than a PACS. In considering the issue it is important to be clear about the nature of the competition facing radiologists. This varies depending on the country and upon whether the institution is public or private. PACS can potentially help to overcome this competition in two ways: by providing real-time radiology, and by enabling teleradiology. Success in these areas requires state-of-the-art implementations of PACS, particularly clinically relevant PACS software, and adequate staffing levels.

Fibrolamellar carcinoma: an unusual clinico-radiological presentation.

We report a case of fibrolamellar carcinoma presenting in a 26-year old female. The patient had gross ascites at presentation. Imaging studies (ultrasonography and computed tomography) strongly suggested extensive intraperitoneal drop metastases.

Interpretation of CT scans with PACS image display in stack mode.

PURPOSE: To compare picture archiving and communication system (PACS) image display in so-called stack mode with conventional image display, tile mode, in efficacy of analysis of three-dimensional structure on computed tomographic (CT) scans. MATERIALS AND METHODS: A complex three-dimensional phantom composed of 20 entangled tubes was constructed and scanned. The resultant images were transferred to a PACS for analysis. Five experienced CT radiologists were asked to unravel the tubes by identifying their ends and to perform this task in both stack and tile modes. The time taken and any errors were recorded. RESULTS: All five radiologists performed considerably faster in stack mode than in tile mode; the speed varied by a factor of 3.2-5.7 times. The results of a paired t test showed this difference to be significant (P = .0002). Furthermore, no mistakes were made in stack mode, while two mistakes were made in tile mode. CONCLUSION: Stack mode facilitates analysis of three-dimensional structure depicted on CT scans.

Spiral CT and the pre-operative assessment of pancreatic adenocarcinoma.

AIM: To determine the value of spiral computed tomography (CT) in the pre-operative assessment of pancreatic carcinoma. PATIENTS AND METHODS: Fifty patients with proven pancreatic carcinoma referred for pancreatoduodenectomy underwent pre-operative spiral CT using a dedicated pancreatic protocol to determine tumour resectability. Twenty-eight patients subsequently underwent surgical exploration. RESULTS: Pre-operative imaging suggested that 15 tumours were resectable, and macroscopic clearance was complete in 13 giving a positive predictive value (PPV) of 87%. PPV of irresectability was 92%. CT underestimated locally advanced disease (n = 2), missed small hepatic metastases (n = 1), and lymphadenopathy (n = 1). CT overestimated SMV encasement in 1 case, otherwise prediction of vascular patency and compromise was correct. The conspicuity of small resectable carcinomas was improved by spiral scanning. CONCLUSION: The optimised pancreatic parenchymal enhancement and vascular opacification achieved by spiral CT improves tumour detection of small carcinomas, allows accurate assessment of peripancreatic vessels, and reliably predicts both resectable and irresectable disease. CT remains inherently limited in the prediction of early extrapancreatic non-vascular spread and of lymphatic metastases.