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•We investigate 18F-flutemetamol pharmacokinetics in probable CAA using PETMR.•We develop a model-based input function (mIF) and assess perfusion and tracer uptake.•We compare measurements from 30 min, against 120 min and SUVR PET-MR.•mIF 1-TC detected impaired perfusion and amyloid load in CAA from both time frames.•Perfusion deficits and amyloid burden were congruent in cases with probable CAA. Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease associated with perivascular β-amyloid deposition. CAA is also associated with strokes due to lobar intracerebral haemorrhage (ICH). 18F-flutemetamol amyloid ligand PET may improve the early detection of CAA. We performed pharmacokinetic modelling using both full (0–30, 90–120 min) and reduced (30 min) 18F-flutemetamol PET-MR acquisitions, to investigate regional cerebral perfusion and amyloid deposition in ICH patients. Dynamic18F-flutemetamol PET-MR was performed in a pilot cohort of sixteen ICH participants; eight lobar ICH cases with probable CAA and eight deep ICH patients. A model-based input function (mIF) method was developed for compartmental modelling. mIF 1-tissue (1-TC) and 2-tissue (2-TC) compartmental modelling, reference tissue models and standardized uptake value ratios were assessed in the setting of probable CAA detection. The mIF 1-TC model detected perfusion deficits and 18F-flutemetamol uptake in cases with probable CAA versus deep ICH patients, in both full and reduced PET acquisition time (all P < 0.05). In the reduced PET acquisition, mIF 1-TC modelling reached the highest sensitivity and specificity in detecting perfusion deficits (0.87, 0.77) and 18F-flutemetamol uptake (0.83, 0.71) in cases with probable CAA. Overall, 52 and 48 out of the 64 brain areas with 18F-flutemetamol-determined amyloid deposition showed reduced perfusion for 1-TC and 2-TC models, respectively. Pharmacokinetic (1-TC) modelling using a 30 min PET-MR time frame detected impaired haemodynamics and increased amyloid load in probable CAA. Perfusion deficits and amyloid burden co-existed within cases with CAA, demonstrating a distinct imaging pattern which may have merit in elucidating the pathophysiological process of CAA.

Identification of lobar spontaneous intracerebral haemorrhage associated with cerebral amyloid angiopathy (CAA) is important because it is associated with a higher risk of recurrent intracerebral haemorrhage than arteriolosclerosis-associated intracerebral haemorrhage. We aimed to develop a prediction model for the identification of CAA-associated lobar intracerebral haemorrhage using CT features and genotype. We identified adults with first-ever intracerebral haemorrhage diagnosed by CT, who died and underwent research autopsy as part of the Lothian IntraCerebral Haemorrhage, Pathology, Imaging and Neurological Outcome (LINCHPIN) study, a prospective, population-based, inception cohort. We determined APOE genotype and radiologists rated CT imaging appearances. Radiologists were not aware of clinical, genetic, and histopathological features. A neuropathologist rated brain tissue for small vessel diseases, including CAA, and was masked to clinical, radiographic, and genetic features. We used CT and APOE genotype data in a logistic regression model, which we internally validated using bootstrapping, to predict the risk of CAA-associated lobar intracerebral haemorrhage, derive diagnostic criteria, and estimate diagnostic accuracy. Among 110 adults (median age 83 years [IQR 76–87], 49 [45%] men) included in the LINCHPIN study between June 1, 2010 and Feb 10, 2016, intracerebral haemorrhage was lobar in 62 (56%) participants, deep in 41 (37%), and infratentorial in seven (6%). Of the 62 participants with lobar intracerebral haemorrhage, 36 (58%) were associated with moderate or severe CAA compared with 26 (42%) that were associated with absent or mild CAA, and were independently associated with subarachnoid haemorrhage (32 [89%] of 36 vs 11 [42%] of 26; p=0·014), intracerebral haemorrhage with finger-like projections (14 [39%] of 36 vs 0; p=0·043), and APOE ɛ4 possession (18 [50%] of 36 vs 2 [8%] of 26; p=0·0020). A prediction model for CAA-associated lobar intracerebral haemorrhage using these three variables had excellent discrimination (c statistic 0·92, 95% CI 0·86–0·98), confirmed by internal validation. For the rule-out criteria, neither subarachnoid haemorrhage nor APOE ɛ4 possession had 100% sensitivity (95% CI 88–100). For the rule-in criteria, subarachnoid haemorrhage and either APOE ɛ4 possession or finger-like projections had 96% specificity (95% CI 78–100). The CT and APOE genotype prediction model for CAA-associated lobar intracerebral haemorrhage shows excellent discrimination in this cohort, but requires external validation. The Edinburgh rule-in and rule-out diagnostic criteria might inform prognostic and therapeutic decisions that depend on identification of CAA-associated lobar intracerebral haemorrhage. UK Medical Research Council, The Stroke Association, and The Wellcome Trust.

Patients with stroke due to spontaneous (non-traumatic) intracerebral haemorrhage (ICH) are at risk of recurrent ICH, ischaemic stroke, and other serious vascular events. We aimed to analyse these risks in population-based studies and compare them with the risks in RESTART, which assessed antiplatelet therapy after ICH. We pooled individual patient data from two prospective, population-based inception cohort studies of all patients with an incident firs-in-a-lifetime ICH in Oxfordshire, England (Oxford Vascular Study; April 1, 2002, to Sept 28, 2018) and Lothian, Scotland, UK (Lothian Audit of the Treatment of Cerebral Haemorrhage; June 1, 2010, to May 31, 2013). We quantified the absolute and relative risks of recurrent ICH, ischaemic stroke, or any serious vascular event (non-fatal stroke, non-fatal myocardial infarction, or vascular death), stratified by ICH location (lobar vs non-lobar) and comorbid atrial fibrillation (AF). We compared pooled event rates with those after allocation to avoid antiplatelet therapy in RESTART. Among 674 patients (mean age 74·7 years [SD 12·6], 320 [47%] men) with 1553 person-years of follow-up, 46 recurrent ICHs (event rate 3·2 per 100 patient-years, 95% CI 2·0–5·1) and 25 ischaemic strokes (1·7 per 100 patient-years, 0·8–3·3) were reported. Patients with lobar ICH (n=317) had higher risk of recurrent ICH (5·1 per 100 patient-years, 95% CI 3·6–7·2) than patients with non-lobar ICH (n=355; 1·8 per 100 patient-years, 1·0–3·3; hazard ratio [HR] 3·2, 95% CI 1·6–6·3; p=0·0010), but there was no evidence of a difference in the risk of ischaemic stroke (1·8 per 100 patient-years, 1·0–3·2, vs 1·6 per 100 patient-years, 0·6–4·4; HR 1·1, 95% CI 0·5–2·8). Conversely, there was no evidence of a difference in recurrent ICH rate in patients with AF (n=147; 3·3 per 100 patient-years, 95% CI 1·0–10·7) compared with those without (n=526; 3·2 per 100 patient-years, 2·2–4·7; HR 0·9, 95% CI 0·4–2·1), but the risk of ischaemic stroke was higher with AF (6·3 per 100 patient-years, 3·7–10·9, vs 0·7 per 100 patient-years, 0·1–5·6; HR 8·2, 3·3–20·3; p<0·0001), resulting in patients with AF having a higher risk of all serious vascular events than patients without AF (15·5 per 100 patient-years, 10·0–24·1, vs 6·8 per 100 patient-years, 3·6–12·5; HR 1·78, 95% CI 1·16–2·74; p=0·0090). Only for patients with lobar ICH without comorbid AF was the risk of recurrent ICH greater than the risk of ischaemic stroke (5·2 per 100 patient-years, 95% CI 3·6–7·5, vs 0·9 per 100 patient-years, 0·2–4·8; p=0·00034). Comparing data from the pooled population-based studies with that from patients allocated to not receive antiplatelet therapy in RESTART, there was no evidence of a difference in the rate of recurrent ICH (3·5 per 100 patient-years, 95% CI 1·9–6·0, vs 4·4 per 100 patient-years, 2·6–6·1) or ischaemic stroke (3·4 per 100 patient-years, 1·9–5·9, vs 5·3 per 100 patient-years, 3·3–7·2). The risks of recurrent ICH, ischaemic stroke, and all serious vascular events after ICH differ by ICH location and comorbid AF. These data enable risk stratification of patients in clinical practice and ongoing randomised trials. UK Medical Research Council, Stroke Association, British Heart Foundation, Wellcome Trust, and the National Institute for Health Research Oxford Biomedical Research Centre.

Objective To determine journal publication rates of scientific papers presented orally at the European Congress of Radiology (ECR) 2010, with comparison of country data to ECR 2000. Methods All oral presentations from ECR 2010 were evaluated for publication between 2010 and 2014 using the MEDLINE database. Countries, collaborations, subspecialties, modalities and study design were ranked by publication percentage. Chi-square tests were used to compare publication percentages for each category of variables. Hazard ratios (HR) were calculated for each country relative to the host nation, Austria. ECR 2010 country statistics were compared with analogous data from ECR 2000. Results In total, 360/840 abstracts were subsequently published (43 %). The author’s country of origin ( p  = 0.02), subspecialty ( p  = 0.02) and study design ( p  = 0.001) were significantly associated with subsequent publication. Switzerland, the Netherlands, France and Germany were among the top six countries by publication percentage in 2000 and 2010. In 2010, Switzerland had the highest publication rate (62 %) and HR in comparison to Austria (HR 2.62 [1.31–5.25], p  = 0.01). Three Asian nations increased relative publication rates over the 10-year period. Conclusion Several European nations consistently convert relatively high percentages of oral abstracts at ECR into publications, and the influence of Asian countries is increasing. Main Messages • Certain European nations consistently publish high percentages of orally presented abstracts at ECR. • The influence of several Asian countries on ECR is increasing. • Country, subspecialty and study design are significantly associated with journal publication. • Authors collaborating internationally have the highest publication rates and mean impact factors. • Among all modalities, PET-CT, MRI and CT have the highest publication percentages.

ObjectiveTo determine whether the presence of diffusion-weighted imaging-positive (DWI+) lesions is associated with recurrent stroke after intracerebral haemorrhage (ICH).MethodsThe REstart or STop Antithrombotics Randomised Trial (RESTART) assessed the effect of restarting versus avoiding antiplatelet therapy after ICH on major vascular events for up to 5 years. We rated DWI sequences of MRI done before randomisation for DWI+ lesion presence, masked to outcome and antiplatelet use. Cox proportional hazards regression models were used to quantify associations.ResultsOf 537 participants in RESTART, 247 (median (IQR) age 75.7 (69.6–81.1) years; 170 men (68.8%); 120 started vs 127 avoided antiplatelet therapy) had DWI sequences on brain MRI at a median of 57 days (IQR 19–103) after ICH, of whom 73 (30%) had one or more DWI+ lesion. During a median follow-up of 2 years (1–3), 18 participants had recurrent ICH and 21 had ischaemic stroke. DWI+ lesion presence was associated with all stroke, (adjusted HR 2.2 (95% CI 1.1 to 4.2)) and recurrent ICH (4.8 (95% CI 1.8 to 13.2)), but not ischaemic stroke (0.9 (95% CI 0.3 to 2.5)). DWI+ lesion presence (0.5 (95% CI 0.2 to 1.3)) vs absence (0.6 (95% CI 0.3 to 1.5), pinteraction=0.66) did not modify the effect of antiplatelet therapy on a composite outcome of recurrent stroke.ConclusionsDWI+ lesion presence in ICH survivors is associated with recurrent ICH, but not with ischaemic stroke. We found no evidence of modification of effects of antiplatelet therapy on recurrent stroke after ICH by DWI+ lesion presence. These findings provide a new perspective on the significance of DWI+ lesions, which may be markers of microvascular mechanisms associated with recurrent ICH.Trial registration number ISRCTN71907627.

Introduction CT angiography (CTA) is often used for assessing patients with acute ischaemic stroke. Only limited observer reliability data exist. We tested inter- and intra-observer reliability for the assessment of CTA in acute ischaemic stroke. Methods We selected 15 cases from the Third International Stroke Trial (IST-3, ISRCTN25765518) with various degrees of arterial obstruction in different intracranial locations on CTA. To assess inter-observer reliability, seven members of the IST-3 expert image reading panel (>5 years experience reading CTA) and seven radiology trainees (<2 years experience) rated all 15 scans independently and blind to clinical data for: presence (versus absence) of any intracranial arterial abnormality (stenosis or occlusion), severity of arterial abnormality using relevant scales (IST-3 angiography score, Thrombolysis in Cerebral Infarction (TICI) score, Clot Burden Score), collateral supply and visibility of a perfusion defect on CTA source images (CTA-SI). Intra-observer reliability was assessed using independently repeated expert panel scan ratings. We assessed observer agreement with Krippendorff’s-alpha (K-alpha). Results Among experienced observers, inter-observer agreement was substantial for the identification of any angiographic abnormality (K-alpha = 0.70) and with an angiography assessment scale (K-alpha = 0.60–0.66). There was less agreement for grades of collateral supply (K-alpha = 0.56) or for identification of a perfusion defect on CTA-SI (K-alpha = 0.32). Radiology trainees performed as well as expert readers when additional training was undertaken (neuroradiology specialist trainees). Intra-observer agreement among experts provided similar results (K-alpha = 0.33–0.72). Conclusion For most imaging characteristics assessed, CTA has moderate to substantial observer agreement in acute ischaemic stroke. Experienced readers and those with specialist training perform best.

Cognitive decline and dementia due to Alzheimer's disease (AD) have been associated with genetic, lifestyle, and environmental factors. A number of potentially modifiable risk factors should be taken into account when preventive or ameliorative interventions targeting dementia and its preclinical stages are investigated. Bone mineral density (BMD) and body composition are two such potentially modifiable risk factors, and their association with cognitive decline was investigated in this study. 164 participants, aged 34-87 years old (62.78 ± 9.27), were recruited for this longitudinal study and underwent cognitive and clinical examinations at baseline and after 3 years. Blood samples were collected for apolipoprotein E (APOE) genotyping and dual energy x-ray absorptiometry (DXA) was conducted at the same day as cognitive assessment. Using hierarchical regression analysis, we found that BMD and lean body mass, as measured using DXA were significant predictors of episodic memory. Age, gender, APOE status, and premorbid IQ were controlled for. Specifically, the List A learning from California Verbal Learning Test was significantly associated with BMD and lean mass both at baseline and at follow up assessment. Our findings indicate that there is a significant association between BMD and lean body mass and episodic verbal learning. While the involvement of modifiable lifestyle factors in human cognitive function has been examined in different studies, there is a need for further research to understand the potential underlying mechanisms.

Cerebral amyloid angiopathy (CAA) is an age-related small vessel disease, characterised pathologically by progressive deposition of amyloid β in the cerebrovascular wall. The Boston criteria are used worldwide for the in-vivo diagnosis of CAA but have not been updated since 2010, before the emergence of additional MRI markers. We report an international collaborative study aiming to update and externally validate the Boston diagnostic criteria across the full spectrum of clinical CAA presentations. In this multicentre, hospital-based, retrospective, MRI and neuropathology diagnostic accuracy study, we did a retrospective analysis of clinical, radiological, and histopathological data available to sites participating in the International CAA Association to formulate updated Boston criteria and establish their diagnostic accuracy across different populations and clinical presentations. Ten North American and European academic medical centres identified patients aged 50 years and older with potential CAA-related clinical presentations (ie, spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes), available brain MRI, and histopathological assessment for CAA diagnosis. MRI scans were centrally rated at Massachusetts General Hospital (Boston, MA, USA) for haemorrhagic and non-haemorrhagic CAA markers, and brain tissue samples were rated by neuropathologists at the contributing sites. We derived the Boston criteria version 2.0 (v2.0) by selecting MRI features to optimise diagnostic specificity and sensitivity in a prespecified derivation cohort (Boston cases 1994–2012, n=159), then externally validated the criteria in a prespecified temporal validation cohort (Boston cases 2012–18, n=59) and a geographical validation cohort (non-Boston cases 2004–18; n=123), comparing accuracy of the new criteria to the currently used modified Boston criteria with histopathological assessment of CAA as the diagnostic standard. We also assessed performance of the v2.0 criteria in patients across all cohorts who had the diagnostic gold standard of brain autopsy. The study protocol was finalised on Jan 15, 2017, patient identification was completed on Dec 31, 2018, and imaging analyses were completed on Sept 30, 2019. Of 401 potentially eligible patients presenting to Massachusetts General Hospital, 218 were eligible to be included in the analysis; of 160 patient datasets from other centres, 123 were included. Using the derivation cohort, we derived provisional criteria for probable CAA requiring the presence of at least two strictly lobar haemorrhagic lesions (ie, intracerebral haemorrhages, cerebral microbleeds, or foci of cortical superficial siderosis) or at least one strictly lobar haemorrhagic lesion and at least one white matter characteristic (ie, severe visible perivascular spaces in centrum semiovale or white matter hyperintensities in a multispot pattern). The sensitivity and specificity of these criteria were 74·8% (95% CI 65·4–82·7) and 84·6% (71·9–93·1) in the derivation cohort, 92·5% (79·6–98·4) and 89·5% (66·9–98·7) in the temporal validation cohort, 80·2% (70·8–87·6) and 81·5% (61·9–93·7) in the geographical validation cohort, and 74·5% (65·4–82·4) and 95·0% (83·1–99·4) in all patients who had autopsy as the diagnostic standard. The area under the receiver operating characteristic curve (AUC) was 0·797 (0·732–0·861) in the derivation cohort, 0·910 (0·828–0·992) in the temporal validation cohort, 0·808 (0·724–0·893) in the geographical validation cohort, and 0·848 (0·794–0·901) in patients who had autopsy as the diagnostic standard. The v2.0 Boston criteria for probable CAA had superior accuracy to the current Boston criteria (sensitivity 64·5% [54·9–73·4]; specificity 95·0% [83·1–99·4]; AUC 0·798 [0·741–0854]; p=0·0005 for comparison of AUC) across all individuals who had autopsy as the diagnostic standard. The Boston criteria v2.0 incorporate emerging MRI markers of CAA to enhance sensitivity without compromising their specificity in our cohorts of patients aged 50 years and older presenting with spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes. Future studies will be needed to determine generalisability of the v.2.0 criteria across the full range of patients and clinical presentations. US National Institutes of Health (R01 AG26484).

Learning points The hyperdense middle cerebral artery sign is a familiar early CT finding in ischaemic stroke and predicts a poor clinical outcome.

Alzheimer's disease (AD) is the major form of age-related dementia worldwide, accounting for more than two-thirds of all dementia cases. The disease is characterized by a progressive loss of cognitive and intellectual functioning (Gilman, 1997). A number of risk factors for AD have been identified. The prevalence of AD increases with age, diabetes, depression, family history of Parkinson's disease and following head injury or exposure to solvents (Jorm et al., 1991; van Duijn et al., 1991; Ott et al., 1995; Yoshitake et al., 1995; Devanand et al., 1996). Published research further suggests that low education levels are associated with increased prevalence of clinical AD (Gatz et al., 2001; Qiu et al., 2001; Ravaglia et al., 2002). Women also have a higher risk for developing the disease than men, with the risk being markedly increased following menopause (Sherwin, 2002; Sherwin 2003). Additionally, slightly more severe cognitive deficits have been reported in AD in women compared to men (Buckwalter et al., 1993, Henderson and Buckwalter, 1994). These epidemiological trends may be a consequence of reproductive hormonal changes. Specifically, menopause results in a marked diminution in gonadal estrogen production in women (see Sherwin, 2003, for a review). Estrogen plays a pivotal role in the maintenance and function of neuronal circuits in the brain and in resistance to neuronal damage (McEwen, 2001). The neuroprotective properties of estrogen are thought to be mediated at least in part by anti-amyloidogenic, anti-oxidative and ant-inflammatory mechanisms (reviewed in Barron et al., 2006a). However, limited and somewhat mixed data exist regarding the association between endogenous levels of estrogen and cognitive decline (Manly et al., 2000; Schupf et al., 2003). Based on some of our own findings, we here consider the factors that may be useful in predicting memory decline as a risk factor for Alzheimer's disease in older post-menopausal women.