Reports are published in Health Technology Assessment (HTA) if (1) they have resulted from work for the HTA programme, and (2) they are of a sufficiently high scientific quality as assessed by the reviewers and editors.Reviews in Health Technology Assessment are termed 'systematic' when the account of the search appraisal and synthesis methods (to minimise biases and random errors) would, in theory, permit the replication of the review by others. HTA programmeThe HTA programme, part of the National Institute for Health Research (NIHR), was set up in 1993. It produces high-quality research information on the effectiveness, costs and broader impact of health technologies for those who use, manage and provide care in the NHS. 'Health technologies' are broadly defined as all interventions used to promote health, prevent and treat disease, and improve rehabilitation and long-term care.The journal is indexed in NHS Evidence via its abstracts included in MEDLINE and its Technology Assessment Reports inform National Institute for Health and Clinical Excellence (NICE) guidance. HTA research is also an important source of evidence for National Screening Committee (NSC) policy decisions.For more information about the HTA programme please visit the website: http://www.hta.ac.uk/ This reportThe research reported in this issue of the journal was funded by the HTA programme as project number 06/303/20. The contractual start date was in April 2007. The draft report began editorial review in January 2012 and was accepted for publication in August 2012. The authors have been wholly responsible for all data collection, analysis and interpretation, and for writing up their work. The HTA editors and publisher have tried to ensure the accuracy of the authors' report and would like to thank the reviewers for their constructive comments on the draft document. However, they do not accept liability for damages or losses arising from material published in this report.This report presents independent research funded by the National Institute for Health Research (NIHR). The views and opinions expressed by authors in this publication are those of the authors and do not necessarily reflect those of the NHS, the NIHR, NETSCC, the HTA programme or the Department of Health. Background: Among trauma patients who survive to reach hospital, exsanguination is a common cause of death. A widely practicable treatment that reduces blood loss after trauma could prevent thousands of premature deaths each year. The CRASH-2 trial aimed to determine the effect of the early administration of tranexamic acid on death and transfusion requirement in bleeding trauma patients. In addition, the effort of tranexamic acid on the risk of vascular occlusive events was assessed.

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We have performed a quantitative analysis of the amyloid load (plaques), neuritic plaques and neurofibrillary tangles (NFT) in the frontal, temporal and parietal association cortices of autopsied brains from 49 prospectively evaluated patients with Alzheimer''s disease (AD) diagnosed according to three sets of published pathological criteria. These patients had been assessed clinically with psychological testing of cognitive abilities within 6 months of death. Correlations were sought between severity of pathological change and cognitive status before death, duration of disease and age at death. Using Khachaturian and CERAD criteria highly positive correlations were obtained between the extent of cognitive deficit and the density of NFT in frontal and parietal lobes. The percentage area of cortex occupied by amyloid in the parietal lobe was correlated to the cognitive deficit only in the CERAD-diagnosed cases. The density of all amyloid plaques (AP) showed no correlation with the extent of cognitive deficit, but the densities of neuritic plaques did correlate with cognitive deficit. Both amyloid load and tangle densities were positively correlated with disease duration. All these correlations were reduced or absent in a sub-group of cases fulfilling the Tierney et al. A3 diagnostic criteria for AD. We found no pathological measure that correlated with the age of patients at death. Amyloid loads and NFT densities showed highly significant but selective positive correlations, the most striking being between temporal lobe NFT density and frontal and parietal lobe amyloid load and between temporal lobe NFT density and frontal and parietal lobe NFT densities. Correlations involving AP density as a measure of amyloid load were almost always less significant than those involving the percentage area of cortex occupied by amyloid, suggesting that the latter measures amyloid load more accurately. However, the highest correlations of NFT densities were with neuritic plaque densities. Overall this study highlights the relevance of neuritic changes (revealed by NFT and neuritic plaques) and the irrelevance of amyloid plaques to the dementia of AD.

In a prospective study of more than 200 cases of dementia and 119 controls, annual technetium-99m–hexamethyl-propylene amineoxime (99m Tc-HMPAO) single-photon emission computed tomography (SPECT) and annual medial temporal lobe (MTL) oriented X-ray computed tomography (CT) have been used to evaluate the diagnostic potential of functional and structural neuroimaging in the differential diagnosis of dementia. Some subjects have had up to 7 annual evaluations. So far, of 151 who have died, 143 (95%) have come to necropsy. Histology is known for 118, of whom 80 had Alzheimer's disease (AD), 24 had other “non-AD” dementias, and 14 controls with no cognitive deficit in life also had no significant central nervous system pathology. To compare the findings in the dementias with the profile of stuctural and functional imaging in the cognitively normal elderly, scan data from 105 living, elderly controls without cognitive deficit have also been included in the analysis. All clinical diagnoses were according to National Institute of Neurological and Communicable Disease and Stroke—Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) and the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; DSM-III-R) criteria, and all histopathological diagnoses according to the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) criteria. Early data from this cohort have suggested that the combination of both MTL atrophy seen on CT with parietotemporal hypoperfusion on SPECT may predict the pathology of AD. The diagnostic sensitivity, specificity, accuracy, and positive and negative predictive values of the NINCDS-ADRDA and DSM-III-R criteria could be assessed in this cohort against the gold standard of histopathology. The diagnostic potential of CT evidence of MTL atrophy alone, SPECT evidence of parietotemporal hypoperfusion alone, and the combination of both of these scan changes in the same individual could then be compared against the diagnostic accuracy of clinical operational criteria in the pathologically confirmed cases. Furthermore, all of these modalities could be compared with the diagnostic accuracy of apolipoprotein E4 (Apo E4) genotyping to predict AD in the histopathologically confirmed cohort. In this population, NINCDS “probable-AD” was 100% specific, 49% sensitive, and 66% accurate; “possible-AD” was only 61% specific, but 93% sensitive and 77% accurate; and the combination of both “probable-AD” and “possible-AD was 61% specific, 96% sensitive, and 85% accurate. DSM-III-R criteria were 51% sensitive, 97% specific, and 66% accurate. In the same cases and including the 105 living, elderly controls, the diagnostic accuracy of the Oxford Project to Investigate Memory and Aging (OPTIMA) scanning criteria showed CT alone to be 85% sensitive, 78% specific, and 80% accurate; SPECT alone had 89% sensitivity, 80% specificity, and 83% accuracy; and the combination of the two was 80% sensitive, 93% specific, and 88% accurate. The Apo E4 genotype was 74% sensitive but yielded 40% false positives in the histologically confirmed series. The diagnostic accuracy afforded by this method of CT and SPECT used alone is better than that of any established clinical criteria and reveals that the combination of MTL atrophy and parietotemporal hypoperfusion is common in AD, much less common in other dementias, and rare in normal controls. In the NINCDS-ADRDA criteria “possible-AD” cases, the combination of CT and SPECT findings alone were better in all diagnostic indices than the presence of Apo E4 alone in predicting AD. The frequent occurrence of MTL atrophy in AD and also in other “non-AD” dementias later in the course of the disease suggests the concept of medial temporal lobe dementia. This could explain some of the overlap of clinical profiles in the dementias, particularly as the dementia progresses, making clinical differential diagnosis difficult. In this context, the use of SPECT can significantly enhance specificity.