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1.
Age Ageing ; 47(1): 95-100, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29106439

RESUMO

Background: hypertension is a risk for brain ageing, but the mechanisms underlying this effect remain unclear. Magnetic resonance imaging (MRI) detected biomarkers of brain ageing include white matter hyperintensities (WMHs), a marker of cerebrovascular disease, and hippocampal volume, a marker of Alzheimer's disease pathology. Objective: to examine relationships between blood pressure (BP) components and brain pathology in older adults. Subjects: two hundred and twenty-seven members of the Aberdeen 1936 Birth Cohort between ages 64 and 68 years. Methods: BP was assessed biennially between 64 and 68 years and brain MRI performed at 68 years. The risk factors of interest were diastolic and systolic BP and their visit-to-visit variability. Outcomes were WMH abundance and hippocampal volume. Regression models, controlling for confounding factors, examined their relationships. Results: higher diastolic BP predicted increased WMH (ß = 0.13, P = 0.044) and smaller hippocampi (ß = -0.25, P = 0.006). In contrast, increased systolic BP predicted larger hippocampi (ß = 0.22, P = 0.013). Variability of diastolic BP predicted lower hippocampal volume (ß = -0.15, P = 0.033). These relationships were independent of confounding life-course risk factors. Anti-hypertensive medication did not modify these relationships, but was independently associated with increased WMH (ß = 0.17, P = 0.011). Conclusion: increased diastolic BP is associated with biomarkers of both cerebrovascular and Alzheimer's diseases, whereas the role of systolic BP is less clear, with evidence for a protective effect on hippocampal volume. These differing relationships emphasise the importance of considering individual BP components with regard to brain ageing and pathology. Interventions targeting diastolic hypertension and its chronic variability may provide new strategies able to slow the accumulation of these harmful pathologies.


Assuntos
Envelhecimento/metabolismo , Doença de Alzheimer/diagnóstico por imagem , Pressão Sanguínea , Transtornos Cerebrovasculares/diagnóstico por imagem , Hipocampo/diagnóstico por imagem , Hipertensão/complicações , Leucoencefalopatias/diagnóstico por imagem , Imageamento por Ressonância Magnética , Substância Branca/diagnóstico por imagem , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/etiologia , Doença de Alzheimer/patologia , Transtornos Cerebrovasculares/etiologia , Transtornos Cerebrovasculares/patologia , Diástole , Feminino , Hipocampo/patologia , Humanos , Hipertensão/diagnóstico , Hipertensão/fisiopatologia , Leucoencefalopatias/etiologia , Leucoencefalopatias/patologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Fatores de Risco , Escócia , Substância Branca/patologia
2.
Aging Ment Health ; 22(8): 915-926, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-28703027

RESUMO

OBJECTIVES: The concept of cognitive reserve (CR) is defined as a moderator, which allows an individual to preserve cognition despite underlying brain pathology. There is no consensus of what potentially modifiable CR determinants are of greatest importance. The aim of this review was to identify life-course factors which protect older individuals from expressing cognitive decline despite the presence of brain pathology. METHOD: A systematic review search was performed in MEDLINE (1946-06/09/13), EMBASE (1947-06/09/13), and PsycheInfo (1967-06/09/13). We included studies examining CR in the context of the four commonest subtypes of dementia, mild cognitive impairment or healthy aging. Studies which combined measurement of underlying dementia-related neuropathology, cognitive function, and factors providing CR in a single model were accepted. We performed a qualitative synthesis of the results. RESULTS: Thirty-four studies out of 9229 screened records met our inclusion criteria and were therefore quality assessed and data extracted. Variation in CR definition made comparison across studies difficult. One hundred and forty-four out of 156 models examined education and occupation: overall, 58% of eligible models classified education and 60% occupation as a CR determinant, with 12% and 44% of those, respectively, being of high quality. Within healthy population suitable to inform preventative interventions, there was consistent evidence for education having a protective effect on general cognition in the face of multiple brain burden measures, while occupation presented inconclusive results within cognitive groups. CONCLUSIONS: Further research on modifiable determinants of CR beyond education/occupation including early-life factors and consensus on CR definition are warranted.


Assuntos
Encéfalo/diagnóstico por imagem , Envelhecimento Cognitivo/fisiologia , Reserva Cognitiva/fisiologia , Demência/fisiopatologia , Escolaridade , Ocupações , Humanos
3.
Neuroimage ; 144(Pt B): 299-304, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-26794641

RESUMO

The Brain Images of Normal Subjects (BRAINS) Imagebank (http://www.brainsimagebank.ac.uk) is an integrated repository project hosted by the University of Edinburgh and sponsored by the Scottish Imaging Network: A Platform for Scientific Excellence (SINAPSE) collaborators. BRAINS provide sharing and archiving of detailed normal human brain imaging and relevant phenotypic data already collected in studies of healthy volunteers across the life-course. It particularly focusses on the extremes of age (currently older age, and in future perinatal) where variability is largest, and which are under-represented in existing databanks. BRAINS is a living imagebank where new data will be added when available. Currently BRAINS contains data from 808 healthy volunteers, from 15 to 81years of age, from 7 projects in 3 centres. Additional completed and ongoing studies of normal individuals from 1st to 10th decades are in preparation and will be included as they become available. BRAINS holds several MRI structural sequences, including T1, T2, T2* and fluid attenuated inversion recovery (FLAIR), available in DICOM (http://dicom.nema.org/); in future Diffusion Tensor Imaging (DTI) will be added where available. Images are linked to a wide range of 'textual data', such as age, medical history, physiological measures (e.g. blood pressure), medication use, cognitive ability, and perinatal information for pre/post-natal subjects. The imagebank can be searched to include or exclude ranges of these variables to create better estimates of 'what is normal' at different ages.


Assuntos
Encéfalo/diagnóstico por imagem , Bases de Dados Factuais , Imageamento por Ressonância Magnética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
4.
Lancet ; 388(10062): 2873-2884, 2016 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-27863809

RESUMO

BACKGROUND: Leuco-methylthioninium bis(hydromethanesulfonate; LMTM), a stable reduced form of the methylthioninium moiety, acts as a selective inhibitor of tau protein aggregation both in vitro and in transgenic mouse models. Methylthioninium chloride has previously shown potential efficacy as monotherapy in patients with Alzheimer's disease. We aimed to determine whether LMTM was safe and effective in modifying disease progression in patients with mild to moderate Alzheimer's disease. METHODS: We did a 15-month, randomised, controlled double-blind, parallel-group trial at 115 academic centres and private research clinics in 16 countries in Europe, North America, Asia, and Russia with patients younger than 90 years with mild to moderate Alzheimer's disease. Patients concomitantly using other medicines for Alzheimer's disease were permitted to be included because we considered it infeasible not to allow their inclusion; however, patients using medicines carrying warnings of methaemoglobinaemia were excluded because the oxidised form of methylthioninium in high doses has been shown to induce this condition. We randomly assigned participants (3:3:4) to 75 mg LMTM twice a day, 125 mg LMTM twice a day, or control (4 mg LMTM twice a day to maintain blinding with respect to urine or faecal discolouration) administered as oral tablets. We did the randomisation with an interactive web response system using 600 blocks of length ten, and stratified patients by severity of disease, global region, whether they were concomitantly using Alzheimer's disease-labelled medications, and site PET capability. Participants, their study partners (generally carers), and all assessors were masked to treatment assignment throughout the study. The coprimary outcomes were progression on the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) and the Alzheimer's Disease Co-operative Study-Activities of Daily Living Inventory (ADCS-ADL) scales from baseline assessed at week 65 in the modified intention-to-treat population. This trial is registered with Clinicaltrials.gov (NCT01689246) and the European Union Clinical Trials Registry (2012-002866-11). FINDINGS: Between Jan 29, 2013, and June 26, 2014, we recruited and randomly assigned 891 participants to treatment (357 to control, 268 to 75 mg LMTM twice a day, and 266 to 125 mg LMTM twice a day). The prespecified primary analyses did not show any treatment benefit at either of the doses tested for the coprimary outcomes (change in ADAS-Cog score compared with control [n=354, 6·32, 95% CI 5·31-7·34]: 75 mg LMTM twice a day [n=257] -0·02, -1·60 to 1·56, p=0·9834, 125 mg LMTM twice a day [n=250] -0·43, -2·06 to 1·20, p=0·9323; change in ADCS-ADL score compared with control [-8·22, 95% CI -9·63 to -6·82]: 75 mg LMTM twice a day -0·93, -3·12 to 1·26, p=0·8659; 125 mg LMTM twice a day -0·34, -2·61 to 1·93, p=0·9479). Gastrointestinal and urinary effects were the most common adverse events with both high doses of LMTM, and the most common causes for discontinuation. Non-clinically significant dose-dependent reductions in haemoglobin concentrations were the most common laboratory abnormality. Amyloid-related imaging abnormalities were noted in less than 1% (8/885) of participants. INTERPRETATION: The primary analysis for this study was negative, and the results do not suggest benefit of LMTM as an add-on treatment for patients with mild to moderate Alzheimer's disease. Findings from a recently completed 18-month trial of patients with mild Alzheimer's disease will be reported soon. FUNDING: TauRx Therapeutics.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Relação Dose-Resposta a Droga , Proteínas tau/antagonistas & inibidores , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/fisiopatologia , Animais , Encéfalo/efeitos dos fármacos , Método Duplo-Cego , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica/estatística & dados numéricos , Falha de Tratamento , Proteínas tau/metabolismo
5.
Age Ageing ; 45(4): 486-93, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27076527

RESUMO

OBJECTIVES: the 'triad of impairment' phenomenon describes the co-occurrence of age-related cognitive, emotional and physical functioning deficits. We investigated how occupational profile and childhood intelligence contribute to the triad of impairment in late life. METHODS: we analysed data of a subsample of the Aberdeen Birth Cohort of 1936 (n = 346). Data were collected on participants' childhood intelligence, late-life cognitive ability, physical functioning, depressive symptoms and main lifetime occupation. We summarised the various occupational and impairment measures into two latent variables, 'occupational profile' and the 'triad of impairment'. We used a series of data reduction approaches and structural equation models (SEMs) of increasing complexity to test both the validity of the models and to understand causal relationships between the life-course risks for the triad of impairment. RESULTS: occupational profile had a significant effect on the triad of impairment independent of childhood intelligence. Childhood intelligence was the predominant influence on the triad of impairment and exerted its effect directly and indirectly via its influence on occupation. The direct effect of childhood intelligence exceeded the independent influence of the occupational profile on impairment by a factor of 1.7-1.8 and was greater by a factor of ∼4 from the indirect pathway (via occupation). CONCLUSIONS: childhood intelligence was the predominant influence on the triad of impairment in late life, independently of the occupational profile. Efforts to reduce impairment in older adults should be informed by a life-course approach with special attention to the early-life environment.


Assuntos
Desenvolvimento Infantil , Transtornos Cognitivos/psicologia , Cognição , Envelhecimento Cognitivo/psicologia , Emoções , Nível de Saúde , Inteligência , Ocupações , Fatores Etários , Idoso , Criança , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/epidemiologia , Depressão/epidemiologia , Depressão/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Medição de Risco , Fatores de Risco , Escócia/epidemiologia , Fatores de Tempo
6.
Neuroimage ; 100: 558-63, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24993896

RESUMO

Brain morphology and cognitive ability change with age. Gray and white matter volumes decrease markedly by the 7th decade of life when cognitive decreases first become readily detectable. As a consequence, the shape complexity of the cortical mantle may also change. The purposes of this study are to examine changes over a five year period in brain structural complexity in late life, and to investigate cognitive correlates of any changes. Brain magnetic resonance images at 1.5 Tesla were acquired from the Aberdeen 1936 Birth Cohort at about ages 68 years (243 participants) and 73 years (148 participants returned). Measures of brain complexity were extracted using Fractal Dimension (FD) and calculated using the box-counting method. White matter complexity, brain volumes and cognitive performance were measured at both 68 and 73 years. Childhood ability was measured at age 11 using the Moray House Test. FD and brain volume decrease significantly from age 68 to 73 years. Using a multilevel linear modeling approach, we conclude that individual decreases in late life white matter complexity are not associated with differences in executive function but are linked to information processing speed, auditory-verbal learning, and reasoning in specific models-with adjustment for childhood mental ability. A significant association was found after adjustment for age, brain volume and childhood mental ability. Complexity of white matter is associated with higher fluid cognitive ability and, in a longitudinal study, predicts retention of cognitive ability within late life.


Assuntos
Envelhecimento/fisiologia , Encéfalo/anatomia & histologia , Cognição/fisiologia , Fractais , Substância Branca/anatomia & histologia , Idoso , Encéfalo/fisiologia , Feminino , Humanos , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Reino Unido , Substância Branca/fisiologia
8.
Eur J Nutr ; 53(1): 277-85, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23625136

RESUMO

PURPOSE: To distinguish between contributions to dementia made by homocysteine, folate, B12 and antioxidant micronutrients. METHODS: This is a follow-up study of a sample reported in 2002. Homocysteine was measured at baseline in 201 individuals born in 1921 and without dementia at age 77 years and followed up to age 88 years. Baseline macro- and micronutrient status was estimated from BMI, the MONICA food frequency questionnaire, plasma folate, B12 and, in a subgroup (N = 173), plasma antioxidant micronutrients. Time to dementia onset during follow-up was compared between participants grouped by homocysteine concentration using Cox regression. Model 1 adjusted for age, sex, childhood IQ, education, socioeconomic deprivation, presence of heart disease, hypertension, plasma folate and B12. In model 2 plasma, antioxidants were added to these covariables. RESULTS: During a mean follow-up of about 5 years, there were 39 incident dementia cases among 201 participants. In model 1, being in the highest homocysteine group (>14 µmol/L) was associated with a 234 % increased risk (HR 3.34, 95 % CI 1.16-9.57) of any dementia. After inclusion of plasma antioxidants in model 2, there were 32 incident dementia cases from a subsample (N = 173). Homocysteine >14 µmol was associated with a 272 % increased dementia risk (HR = 3.72, 95 % CI 1.06-13.08). CONCLUSIONS: High homocysteine increases the risk of dementia. The association between tHcy and dementia is independent of plasma folate, B12 and antioxidant micronutrient status.


Assuntos
Antioxidantes/metabolismo , Demência/diagnóstico , Homocisteína/sangue , Micronutrientes/sangue , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Cognição/fisiologia , Demência/sangue , Demência/etiologia , Feminino , Ácido Fólico/sangue , Seguimentos , Humanos , Hiper-Homocisteinemia/complicações , Masculino , Avaliação Nutricional , Modelos de Riscos Proporcionais , Fatores de Risco , Fatores Socioeconômicos , Inquéritos e Questionários , Vitamina B 12/sangue
9.
Br J Radiol ; 97(1153): 120-125, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38263824

RESUMO

OBJECTIVES: To determine factors influencing reader agreement in breast screening and investigate the relationship between agreement level and patient outcomes. METHODS: Reader pair agreement for 83 265 sets of mammograms from the Scottish Breast Screening service (2015-2020) was evaluated using Cohen's kappa statistic. Each mammography examination was read by two readers, per routine screening practice, with the second initially blinded but able to choose to view the first reader's opinion. If the two readers disagreed, a third reader arbitrated. Variation in reader agreement was examined by: whether the reader acted as the first or second reader, reader experience, and recall, cancer detection and arbitration recall rate. RESULTS: Readers' opinions varied by whether they acted as the first or second reader. Furthermore, reader 2 was more likely to agree with reader 1 if reader 1 was more experienced than they were, and less likely to agree if they themselves were more experienced than reader 1 (P < .001). Agreement was not significantly associated with cancer detection rate, overall recall rate or arbitration recall rates (P > .05). Lower agreement between readers led to a higher arbiter workload (P < .001). CONCLUSIONS: In mammography screening, the second reader's opinion is influenced by the first reader's opinion, with the degree of influence dependent on the readers' relative experience levels. ADVANCES IN KNOWLEDGE: While less-experienced readers relied on their more experienced reading partner, no adverse impact on service outcomes was observed. Allowing access to the first reader's opinion may benefit newly qualified readers, but reduces independent evaluation, which may lower cancer detection rates.


Assuntos
Neoplasias da Mama , Detecção Precoce de Câncer , Humanos , Feminino , Estudos Retrospectivos , Mamografia , Mama
10.
Ann Neurol ; 71(5): 653-60, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22522480

RESUMO

OBJECTIVE: To investigate in older adults without dementia the relationships between socioeconomic status (SES) in childhood and magnetic resonance imaging (MRI)-derived brain volume measures typical of brain aging and Alzheimer's disease (AD). METHODS: Using a cross-sectional and longitudinal observation approach, we invited volunteers without dementia, all born in 1936, and who were participants in the 1947 Scottish Mental Survey, for MR brain imaging; 249 of 320 (77%) agreed. We measured whole brain and hippocampal volumes and recorded childhood SES history, the number of years of education undertaken, and adult SES history. Mental ability at age 11 years was recorded in 1947 and was also available. RESULTS: Analysis shows a significant association between childhood SES and hippocampal volume after adjusting for mental ability at age 11 years, adult SES, gender, and education. INTERPRETATION: A significant association between childhood SES and hippocampal volumes in late life is consistent with the established neurodevelopmental findings that early life conditions have an effect on structural brain development. This remains detectable more than 50 years later.


Assuntos
Hipocampo/anatomia & histologia , Classe Social , Idoso , Criança , Estudos Transversais , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade
11.
Depress Anxiety ; 30(1): 77-84, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23165823

RESUMO

BACKGROUND: The influence of white matter lesions on depressive symptoms in healthy ageing populations remains unclear. In this study, we examined the relationship between depressive symptoms and magnetic resonance imaging (MRI) detected cerebrovascular disease in a normal population living independently in the community, and measured the influence of location of brain abnormalities, fluid intelligence, living alone, and sex. METHODS: Prospective cohort: 497 community dwelling individuals all born in 1936, who took part in the Scottish Mental Survey of 1947, were followed up in 2000 and at biannual intervals in a longitudinal study of health and cognitive aging. Two hundred forty-four volunteered for brain MRI in 2004-2006. Suitable data were available in 219/244, of whom 115 were men. Brain hyperintensities in lobar white matter, basal ganglia , periventricular, and infratentorial regions were measured using Scheltens' scale. Depressed mood was assessed using the Hospital Anxiety and Depression Scale (HADS) on three biannual intervals. Relationships between Scheltens' scores, HADS-D scores, fluid intelligence, living alone, and sex were assessed using general linear modeling. RESULTS: The main predictor of depressive symptom scores was poorer fluid intelligence (partial η(2) =0.023-0.028, P < .05). Ischemic change in the brainstem (partial η(2) = 0.026, P ≤.05) and basal ganglia (partial η(2) =0.018, P ≤ .05) also predicted HADS-D scores. There was no relationship with sex or living alone. CONCLUSIONS: Hyperintensities in the brainstem and basal ganglia are associated with depressive symptoms. Higher fluid intelligence is associated with lower depressive symptoms in this normal, ageing population.


Assuntos
Envelhecimento/psicologia , Isquemia Encefálica/psicologia , Encéfalo/patologia , Depressão/patologia , Inteligência , Fibras Nervosas Mielinizadas/patologia , Idoso , Envelhecimento/patologia , Gânglios da Base/patologia , Isquemia Encefálica/patologia , Tronco Encefálico/patologia , Estudos de Coortes , Feminino , Humanos , Modelos Lineares , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Estudos Prospectivos
12.
Int J Geriatr Psychiatry ; 28(1): 75-81, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22821632

RESUMO

OBJECTIVE: We aimed to investigate three reports of a possible role of early parental death in late onset dementia. We tested a multivariate model of risk factors for late onset dementia that included established (female sex, a family history of dementia, APOE ε4) and putative influences (vascular risk factors, years of full-time education, parental ages at death, and childhood IQ) on dementia risk. METHODS: We examined contributions of early life and late life risk factors for dementia by using childhood social and family data and blood samples obtained at interview at age about 78 years. In 1997-1999, we recruited 281 subjects without dementia from a 1932 Scottish IQ survey of children born in 1921 and followed them up to 2010 (at age 88). Binary logistic regression and Bayesian structural equation modelling were used to model dementia risk. RESULTS: Risk of dementia was associated with increasing age from 77 to 88 years, female sex, death of either parent before age 11 and APOE ε4 genotype. Family history of dementia, childhood IQ, years of education and vascular risk factors did not contribute to the model. CONCLUSIONS: Our multivariate models of the possible causes of late onset dementia confirm previous associations of dementia with female sex and APOE ε4 genotype and supports earlier reports of a role for early parental death.


Assuntos
Demência/etiologia , Morte Parental , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Apolipoproteína E4/genética , Demência/genética , Feminino , Humanos , Modelos Logísticos , Masculino , Análise Multivariada , Fatores de Risco , Fatores Sexuais
13.
Nucl Med Commun ; 44(10): 834-842, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37464866

RESUMO

OBJECTIVES: With disease-modifying therapies in development for neurological disorders, quantitative brain imaging techniques become increasingly relevant for objective early diagnosis and assessment of response to treatment. The aim of this study was to evaluate the use of Brain SPECT and PET scans in the UK and explore drivers and barriers to using quantitative analysis through an online survey. METHODS: A web-based survey with 27 questions was used to capture a snapshot of brain imaging in the UK. The survey included multiple-choice questions assessing the availability and use of quantification for DaTscan, Perfusion SPECT, FDG PET and Amyloid PET. The survey results were reviewed and interpreted by a panel of imaging experts. RESULTS: Forty-six unique responses were collected and analysed, with 84% of responses from brain imaging sites. Within these sites, 88% perform DaTscan, 50% Perfusion SPECT, 48% FDG PET, and 33% Amyloid PET, while a few sites use other PET tracers. Quantitative Brain analysis is used in 86% of sites performing DaTscans, 40% for Perfusion SPECT, 63% for FDG PET and 42% for Amyloid PET. Commercial tools are used more frequently than in-house software. CONCLUSION: The survey showed variations across the UK, with high availability of DaTscan imaging and quantification and lower availability of other SPECT and PET scans. The main drivers for quantification were improved reporting confidence and diagnostic accuracy, while the main barriers were a perception of a need for an appropriate database of healthy controls and a lack of training, time, and software availability.


Assuntos
Fluordesoxiglucose F18 , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Tomografia por Emissão de Pósitrons/métodos , Encéfalo/diagnóstico por imagem , Amiloide , Reino Unido
14.
Radiol Artif Intell ; 5(3): e220146, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37293340

RESUMO

Artificial intelligence (AI) tools may assist breast screening mammography programs, but limited evidence supports their generalizability to new settings. This retrospective study used a 3-year dataset (April 1, 2016-March 31, 2019) from a U.K. regional screening program. The performance of a commercially available breast screening AI algorithm was assessed with a prespecified and site-specific decision threshold to evaluate whether its performance was transferable to a new clinical site. The dataset consisted of women (aged approximately 50-70 years) who attended routine screening, excluding self-referrals, those with complex physical requirements, those who had undergone a previous mastectomy, and those who underwent screening that had technical recalls or did not have the four standard image views. In total, 55 916 screening attendees (mean age, 60 years ± 6 [SD]) met the inclusion criteria. The prespecified threshold resulted in high recall rates (48.3%, 21 929 of 45 444), which reduced to 13.0% (5896 of 45 444) following threshold calibration, closer to the observed service level (5.0%, 2774 of 55 916). Recall rates also increased approximately threefold following a software upgrade on the mammography equipment, requiring per-software version thresholds. Using software-specific thresholds, the AI algorithm would have recalled 277 of 303 (91.4%) screen-detected cancers and 47 of 138 (34.1%) interval cancers. AI performance and thresholds should be validated for new clinical settings before deployment, while quality assurance systems should monitor AI performance for consistency. Keywords: Breast, Screening, Mammography, Computer Applications-Detection/Diagnosis, Neoplasms-Primary, Technology Assessment Supplemental material is available for this article. © RSNA, 2023.

15.
Neuroimage ; 61(3): 694-701, 2012 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-22510257

RESUMO

Fractal measures such as fractal dimension (FD) can quantify the structural complexity of the brain. These have been used in clinical neuroscience to investigate brain development, ageing and in studies of psychiatric and neurological disorders. Here, we examined associations between the FD of white matter and cognitive changes across the life course in the absence of detectable brain disease. The FD was calculated from segmented cerebral white matter MR images in 217 subjects aged about 68years, in whom archived intelligence scores from age 11years were available. Cognitive test scores of fluid and crystallised intelligence were obtained at the time of MR imaging. Significant differences were found (intracranial volume, brain volume, white matter volume and Raven's Progressive Matrices score) between men and women at age 68years and novel associations were found between FD and measures of cognitive change over the life course from age 11 to 68years. Those with greater FD were found to have greater than expected fluid abilities at age 68years than predicted by their childhood intelligence and less cognitive decline from age 11 to 68years. These results are consistent with other reports that FD measures of cortical structural complexity increase across the early life course during maturation of the cerebral cortex and add new data to support an association between FD and cognitive ageing.


Assuntos
Encéfalo/crescimento & desenvolvimento , Encéfalo/fisiologia , Cognição/fisiologia , Fractais , Adulto , Idoso , Envelhecimento/fisiologia , Algoritmos , Encéfalo/anatomia & histologia , Criança , Estudos de Coortes , Bases de Dados Factuais , Escolaridade , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Individualidade , Inteligência/fisiologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Escócia , Caracteres Sexuais
16.
Eur Radiol ; 22(7): 1385-94, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22354559

RESUMO

OBJECTIVE: To document accessible magnetic resonance (MR) brain images, metadata and statistical results from normal older subjects that may be used to improve diagnoses of dementia. METHODS: We systematically reviewed published brain image databanks (print literature and Internet) concerned with normal ageing brain structure. RESULTS: From nine eligible databanks, there appeared to be 944 normal subjects aged ≥60 years. However, many subjects were in more than one databank and not all were fully representative of normal ageing clinical characteristics. Therefore, there were approximately 343 subjects aged ≥60 years with metadata representative of normal ageing, but only 98 subjects were openly accessible. No databank had the range of MR image sequences, e.g. T2*, fluid-attenuated inversion recovery (FLAIR), required to effectively characterise the features of brain ageing. No databank supported random subject retrieval; therefore, manual selection bias and errors may occur in studies that use these subjects as controls. Finally, no databank stored results from statistical analyses of its brain image and metadata that may be validated with analyses of further data. CONCLUSION: Brain image databanks require open access, more subjects, metadata, MR image sequences, searchability and statistical results to improve understanding of normal ageing brain structure and diagnoses of dementia. KEY POINTS: • We reviewed databanks with structural MR brain images of normal older people. • Among these nine databanks, 98 normal subjects ≥60 years were openly accessible. • None had all the required sequences, random subject retrieval or statistical results. • More access, subjects, sequences, metadata, searchability and results are needed. • These may improve understanding of normal brain ageing and diagnoses of dementia.


Assuntos
Envelhecimento/patologia , Envelhecimento/fisiologia , Encéfalo/anatomia & histologia , Encéfalo/crescimento & desenvolvimento , Bases de Dados Factuais/estatística & dados numéricos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Sistemas de Informação em Radiologia/estatística & dados numéricos , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
17.
Brain ; 134(Pt 12): 3687-96, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22102649

RESUMO

The cognitive reserve hypothesis explains the disparity between clinical and pathological phenotypes and why, in two individuals with the same extent of neuropathology, one may be demented while the other remains cognitively intact. We examined the balance between brain magnetic resonance imaging measures of the two most common pathologies associated with brain ageing, cerebrovascular disease and Alzheimer's disease, and parameters of cerebral reserve in well-characterized participants born in 1936, for whom childhood intelligence is known. Brain magnetic resonance imaging was carried out at 1.5T using fluid attenuation inversion recovery and T(1)-weighted volumetric sequences in 249 participants. Cerebrovascular disease was quantified by measuring brain white matter hyperintensities on fluid attenuation inversion recovery images using Scheltens' scale and Alzheimer's disease was measured from volumetric data using FreeSurfer to extract whole brain volume and hippocampal volumes in turn. The effect of these measures of brain burden on life-long cognitive ageing from the age of 11 to 68 years was compared with the effect of educational attainment and occupational grade using structural equation modelling. Complete brain burden and reserve data were available in 224 participants. We found that educational attainment, but not occupation, has a measurable and positive effect, with a standardized regression weight of +0.23, on late life cognitive ability in people without cognitive impairment aged 68 years, allowing for the influence of childhood intelligence and the two most common subclinical brain pathological burdens in the ageing brain. In addition, we demonstrate that the magnitude of the contribution of education is greater than the negative impact of either neuropathological burden alone, with standardized regression weights of -0.14 for white matter hyperintensities and -0.20 for hippocampal atrophy. This study illustrates how education counteracts the deleterious effects of cerebrovascular disease and Alzheimer's disease and highlights the importance of quantifying cognitive reserve in dementia research.


Assuntos
Doença de Alzheimer/patologia , Encéfalo/patologia , Transtornos Cerebrovasculares/patologia , Transtornos Cognitivos/patologia , Cognição/fisiologia , Reserva Cognitiva/fisiologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/psicologia , Atrofia/patologia , Encéfalo/fisiopatologia , Transtornos Cerebrovasculares/fisiopatologia , Transtornos Cerebrovasculares/psicologia , Transtornos Cognitivos/fisiopatologia , Transtornos Cognitivos/psicologia , Escolaridade , Feminino , Humanos , Inteligência , Imageamento por Ressonância Magnética , Masculino , Modelos Neurológicos , Testes Neuropsicológicos
18.
Brain Sci ; 12(3)2022 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-35326274

RESUMO

The Aberdeen birth cohorts of 1921 and 1936 (ABC21 and ABC36) were subjected to IQ tests in 1932 or 1947 when they were aged about 11y. They were recruited between 1997-2001 among cognitively healthy community residents and comprehensively phenotyped in a long-term study of brain aging and health up to 2017. Here, we report associations between baseline cognitive test scores and long-term cognitive outcomes. On recruitment, significant sex differences within and between the ABC21 and ABC36 cohorts supported advantages in verbal ability and learning among the ABC36 women that were not significant in ABC21. Comorbid physical disorders were self-reported in both ABC21 and ABC36 but did not contribute to differences in terms of performance in cognitive tests. When used alone without other criteria, cognitive tests scores which fell below the -1.5 SD criterion for tests of progressive matrices, namely verbal learning, digit symbol and block design, did not support the concept that Mild Cognitive Impairment (MCI) is a stable class of acquired loss of function with significant links to the later emergence of a clinical dementia syndrome. This is consistent with many previous reports. Furthermore, because childhood IQ-type data were available, we showed that a lower cognitive performance at about 64 or 78 y than that predicted by IQ at 11 ± 0.5 y did not improve the prediction of progress to MCI or greater cognitive loss. We used binary logistic regression to explore how MCI might contribute to the prediction of later progress to a clinical dementia syndrome. In a fully adjusted model using ABC21 data, we found that non-amnestic MCI, along with factors such as female sex and depressive symptoms, contributed to the prediction of later dementia. A comparable model using ABC36 data did not do so. We propose that (1) MCI criteria restricted to cognitive test scores do not improve the temporal stability of MCI classifications; (2) pathways towards dementia may differ according to age at dementia onset and (3) the concept of MCI may require measures (not captured here) that underly self-reported subjective age-related cognitive decline.

19.
Clin Breast Cancer ; 22(5): e674-e679, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35279407

RESUMO

BACKGROUND: Sentinel Lymph Node Biopsy (SLNB) is used to stage the axilla, but there is limited data in patients with prior ipsilateral breast cancer. This study compares redo-SLNB (reSLNB) and Axillary node sample (ANS) in this sub-cohort of patients. MATERIALS AND METHODS: This is a retrospective study looking at patients with a new ipsilateral primary or recurrence with history of breast-conserving surgery. Planned and performed surgery, patient demographics and previous treatments were recorded. Node positivity and success rate of reSLNB was analyzed. RESULTS: A total of 86 patients were identified that had mastectomy for ipsilateral recurrent disease with radiologically negative axilla. Out of the 48 that had reSLNB, 35(72.9%) were successful. Nineteen percent of the reSLNB had positive axillae and 20% of the ANS patients. reSLNB success rate was significantly lower amongst patients with previous axillary surgery (P = .014) and previous positive nodes(P = .001). CONCLUSION: reSLNB should be considered to restage the axilla in patients with previous history of ipsilateral cancer especially that there is growing evidence showing good identification rate.


Assuntos
Neoplasias da Mama , Biópsia de Linfonodo Sentinela , Axila/patologia , Axila/cirurgia , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Feminino , Humanos , Linfonodos/patologia , Mastectomia , Recidiva Local de Neoplasia/cirurgia , Estudos Retrospectivos
20.
Insights Imaging ; 13(1): 186, 2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36484919

RESUMO

OBJECTIVES: This study surveyed the views of breast screening readers in the UK on how to incorporate Artificial Intelligence (AI) technology into breast screening mammography. METHODS: An online questionnaire was circulated to the UK breast screening readers. Questions included their degree of approval of four AI implementation scenarios: AI as triage, AI as a companion reader/reader aid, AI replacing one of the initial two readers, and AI replacing all readers. They were also asked to rank five AI representation options (discrete opinion; mammographic scoring; percentage score with 100% indicating malignancy; region of suspicion; heat map) and indicate which evidence they considered necessary to support the implementation of AI into their practice among six options offered. RESULTS: The survey had 87 nationally accredited respondents across the UK; 73 completed the survey in full. Respondents approved of AI replacing one of the initial two human readers and objected to AI replacing all human readers. Participants were divided on AI as triage and AI as a reader companion. A region of suspicion superimposed on the image was the preferred AI representation option. Most screen readers considered national guidelines (77%), studies using a nationally representative dataset (65%) and independent prospective studies (60%) as essential evidence. Participants' free-text comments highlighted concerns and the need for additional validation. CONCLUSIONS: Overall, screen readers supported the introduction of AI as a partial replacement of human readers and preferred a graphical indication of the suspected tumour area, with further evidence and national guidelines considered crucial prior to implementation.

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