Cauda equina syndrome following a lumbar puncture.

Lumbar puncture (LP), a common diagnostic procedure, is usually associated with low morbidity. We describe the case of a 29-year-old woman who underwent a non-traumatic LP in the setting of normal coagulation. Cauda equina syndrome subsequently developed secondary to an extradural spinal haematoma. Avoidance, identification and management of this uncommon complication are discussed. Iatrogenic cauda equina syndrome following LP is rare, but can cause significant morbidity. Our patient's experience and our review of the literature highlight that: (i) normal coagulation and a non-traumatic LP do not exclude this diagnostic possibility; (ii) early recognition determines the management and prognosis, as 50% of patients remain paraplegic if the condition is identified more than 12 hours after symptom onset; and (iii) neurosurgical intervention can be avoided, despite bladder dysfunction, if there are early signs of recovery

Does a novel X-ray imaging technology provide a substantial radiation dose reduction for patients in trans-catheter aortic valve implantation procedures?

Purpose: Modern interventional X-ray equipment employs image processing to permit reduction in radiation whilst retaining sufficient image quality. The aim of this study was to investigate whether our recently-installed system (AlluraClarity, Philips Healthcare) which contains advanced real-time image noise reduction algorithms and anatomy-specific X-ray optimization (beam filtering, grid switch, pulse width, spot size, detector and image processing engine), affected patient procedure dose and overall procedure duration in routine trans-catheter aortic valve implantation (TAVI) procedures. Methods: Patient dose for 42 TAVI patients from the AlluraClarity cardiac catheterisation lab and from a reference system (Axiom Artis, Siemens Healthcare) in the same cardiology department was recorded. Median values from the two X-ray systems were compared using the Wilcoxon statistical test. Results: Total patient procedure dose medians were 4016 and 7088 cGy cm2 from the AlluraClarity and reference systems respectively. AlluraClarity median patient doses were 3405 cGy cm2 and 783.5 cGy cm2 from fluoroscopy and digital image acquisition respectively. Reference median patient doses were 4928 cGy cm2 and 2511 cGy cm2 from fluoroscopy and digital image acquisition respectively. All differences in patient dose were significant at the 5% level. Median total fluoroscopy times [min:sec] were 19:57 and 20:20 for the AlluraClarity and reference systems respectively. Conclusion: The AlluraClarity cardiac catheterisation lab had 43% lower total patient procedure dose for TAVI patients than the reference lab; fluoroscopy and digital image acquisition doses were 31% and 69% lower respectively. In terms of total fluoroscopy time, there was no statistically significant difference between the two labs

A starting point in the evaluation of the outcome of care: an example using cancer registry information

Many health services worldwide are paying increasing attention to the evaluation of care. However, most studies in the past have concentrated on structure and process instead of outcome. The objective of this paper is to show how a fairly simple technique can provide a possible feedback loop to a health service system. A study on patients with lung cancer in East Anglia, UK is used as an example. Using information which was more or less routinely collected in cancer registration, the study showed that there was no significant difference between the survival of patients seen in the eight districts in East Anglia. Adjustment by the use proportional hazard modelling for prognostic factors including age, sex, histological type, stage and whether active treatment was given did not alter the outcome. This finding was slightly unexpected in view of the presumed (yet not documented) variation in enthusiasm and expertise among the districts. Such a result should be seen as a starting point for studies designed to examine the effects of the level of care provided and resource use on the length and quality of survival. While the methodology requires refinement and substantial local difficulties may arise, development of similar researches on the outcome of care should be encouraged in Hong Kong.published_or_final_versio

Canonical Generations and the British Left: The Narrative Construction of the Miners’ Strike 1984–85

‘Generations’ have been invoked to describe a variety of social and cultural relationships, and to understand the development of self-conscious group identity. Equally, the term can be an applied label and politically useful construct; generations can be retrospectively produced. Drawing on the concept of ‘canonical generations’ – those whose experiences come to epitomise an event of historic and symbolic importance – this article examines the narrative creation and functions of ‘generations’ as collective memory shapes and re-shapes the desire for social change. Building a case study of the canonical role of the miners’ strike of 1984–85 in the narrative history of the British left, it examines the selective appropriation and transmission of the past in the development of political consciousness. It foregrounds the autobiographical narratives of activists who, in examining and legitimising their own actions and prospects, (re)produce a ‘generation’ in order to create a relatable and useful historical understanding

Image quality based x-ray dose control in cardiac imaging

An automated closed-loop dose control system balances the radiation dose delivered to patients and the quality of images produced in cardiac x-ray imaging systems. Using computer simulations, this study compared two designs of automatic x-ray dose control in terms of the radiation dose and quality of images produced. The first design, commonly in x-ray systems today, maintained a constant dose rate at the image receptor. The second design maintained a constant image quality in the output images. A computer model represented patients as a polymethylmetacrylate phantom (which has similar x-ray attenuation to soft tissue), containing a detail representative of an artery filled with contrast medium. The model predicted the entrance surface dose to the phantom and contrast to noise ratio of the detail as an index of image quality. Results showed that for the constant dose control system, phantom dose increased substantially with phantom size (x5 increase between 20cm and 30 cm thick phantom), yet the image quality decreased by 43% for the same thicknesses. For the constant quality control, phantom dose increased at a greater rate with phantom thickness (>x10 increase between 20 cm and 30 cm phantom). Image quality based dose control could tailor the x-ray output to just achieve the quality required, which would reduce dose to patients where the current dose control produces images of too high quality. However, maintaining higher levels of image quality for large patients would result in a significant dose increase over current practice

Temporal trends in safety of carotid endarterectomy in asymptomatic patients

Objective: To systematically review temporal changes in perioperative safety of carotid endarterectomy (CEA) in asymptomatic individuals in trial and registry studies. Methods: The MEDLINE and EMBASE databases were searched using the terms “carotid” and “endarterectomy” and “asymptomatic” from 1947 to August 23, 2014. Articles dealing with 50%–99% stenosis in asymptomatic individuals were included and low-volume studies were excluded. The primary endpoint was 30-day stroke or death and the secondary endpoint was 30-day all-cause mortality. Statistical analysis was performed using random-effects meta-regression for registry data and for trial data graphical interpretation alone was used. Results: Six trials (n = 4,431 procedures) and 47 community registries (n = 204,622 procedures) reported data between 1983 and 2013. Registry data showed a significant decrease in postoperative stroke or death incidence over the period 1991–2010, equivalent to a 6% average proportional annual reduction (95% credible interval [CrI] 4%–7%; p < 0.001). Considering postoperative all-cause mortality, registry data showed a significant 5% average proportional annual reduction (95% CrI 3%–9%; p < 0.001). Trial data showed a similar visual trend. Conclusions: CEA is safer than ever before and high-volume registry results closely mirror the results of trials. New benchmarks for CEA are a stroke or death risk of 1.2% and a mortality risk of 0.4%. This information will prove useful for quality improvement programs, for health care funders, and for those re-examining the long-term benefits of asymptomatic revascularization in future trials

Machine vision image quality measurement in cardiac x-ray imaging

The purpose of this work is to report on a machine vision approach for the automated measurement of x-ray image contrast of coronary arteries filled with iodine contrast media during interventional cardiac procedures. A machine vision algorithm was developed that creates a binary mask of the principal vessels of the coronary artery tree by thresholding a standard deviation map of the direction image of the cardiac scene derived using a Frangi filter. Using the mask, average contrast is calculated by tting a Gaussian model to the greyscale profile orthogonal to the vessel centre line at a number of points along the vessel. The algorithm was applied to sections of single image frames from 30 left and 30 right coronary artery image sequences from different patients. Manual measurements of average contrast were also performed on the same images. A Bland-Altman analysis indicates good agreement between the two methods with 95% confidence intervals -0.046 to +0.048 with a mean bias of 0.001. The machine vision algorithm has the potential of providing real-time context sensitive information so that radiographic imaging control parameters could be adjusted on the basis of clinically relevant image content

Selecting stimuli parameters for video quality studies based on perceptual similarity distances

This work presents a methodology to optimize the selection of multiple parameter levels of an image acquisition, degradation, or post-processing process applied to stimuli intended to be used in a subjective image or video quality assessment (QA) study. It is known that processing parameters (e.g. compression bit-rate) or technical quality measures (e.g. peak signal-to-noise ratio, PSNR) are often non-linearly related to human quality judgment, and the model of either relationship may not be known in advance. Using these approaches to select parameter levels may lead to an inaccurate estimate of the relationship between the parameter and subjective quality judgments – the system’s quality model. To overcome this, we propose a method for modeling the relationship between parameter levels and perceived quality distances using a paired comparison parameter selection procedure in which subjects judge the perceived similarity in quality. Our goal is to enable the selection of evenly sampled parameter levels within the considered quality range for use in a subjective QA study. This approach is tested on two applications: (1) selection of compression levels for laparoscopic surgery video QA study, and (2) selection of dose levels for an interventional X-ray QA study. Subjective scores, obtained from the follow-up single stimulus QA experiments conducted with expert subjects who evaluated the selected bit-rates and dose levels, were roughly equidistant in the perceptual quality space - as intended. These results suggest that a similarity judgment task can help select parameter values corresponding to desired subjective quality levels