Impact of a telephone-first consultation system in general practice.

PURPOSE OF THE STUDY: Increasing pressure on general practice prompts innovative change in service organisation. This study sought to evaluate the impact of introducing a telephone-first consultation system in a socioeconomically deprived population. STUDY DESIGN: An interrupted time series of preplanned outcomes for 2 years before and 1 year postintroduction of a telephone-first system was used to measure the volume and type of general practitioner (GP) consultations and the number of patients consulted per year. Emergency department (ED) and GP out-of-hours attendances, the number of outpatient referrals, and the number of requests for laboratory tests were measured as secondary outcomes. RESULTS: The telephone-first system was associated with a 20% increase in total GP consultations (telephone and face-to-face, effect estimate at 12 months, p=0.001). Face-to-face consultations decreased by 39% (p<0.001), while telephone consultations increased by 131% (p<0.001). The volume of individual patient requests for a GP consultation and the number of treatment room nurse consultations did not change. Secondary outcome measures showed no change in hospital outpatient referrals, number of requests for laboratory tests, and ED or GP out-of-hours attendances. CONCLUSIONS: A telephone-first system in a deprived urban general practice can decrease delays to GP-patient contacts. The number of patients seeking a medical intervention did not differ irrespective of the consultation system used. The telephone-first system did not affect GP out-of-hours, laboratory investigations or secondary care contacts.

Radiological Eye Deviation as a Predictor of Large Vessel Occlusion in Acute Ischaemic Stroke.

BACKGROUND: Detection of large vessel occlusion (LVO) is required for endovascular therapy in acute ischemic stroke (AIS) but CT angiography (CTA) is not always performed at primary stroke centers. Eye deviation on CT brain has been associated with improved stroke detection, but comparisons with angiographic status have been limited. This study sought to determine if radiological eye deviation was associated with LVO. METHODS: All AIS patients given intravenous thrombolysis who had acute CTA performed in 2 stroke units were reviewed over 2013-2015 for the presence of LVO. Eye deviation was determined by 2 clinicians blinded to LVO status. Logistic regression was performed to determine which factors predicated LVO. RESULTS: Total 195 AIS patients with acute CTA were identified; 124 (64%) had LVO. Median age was 72 (IQR 64-82) years, median National Institutes of Health Stroke Scale (NIHSS) was 12 (IQR 7-14). LVO patients had a higher NIHSS (15 versus 7, p < .01) and were more likely to have eye deviation on CT brain (71% versus 22.5%, p < .01). Logistic regression confirmed NIHSS score and eye deviation were associated with LVO, with odds ratios of 1.15 (per point) and 5.13 respectively. NIHSS less than equal to 11 gave greatest sensitivity (78.5%) and specificity (76.1%) for LVO with a positive predictive value of 84.7%. Eye deviation was similar with sensitivity 71%, specificity 77.5%, and 84.6%. CONCLUSIONS: Eye deviation on CT brain is strongly associated with LVO. Presence of eye deviation on CT should alert clinicians to probability of LVO and for formal angiographic testing if not already performed.

Infratentorial superficial siderosis: Classification, diagnostic criteria, and rational investigation pathway.

Central nervous system infratentorial superficial siderosis (iSS) is increasingly detected by blood-sensitive magnetic resonance imaging (MRI) sequences. Despite this, there are no standardized diagnostic criteria, and the clinical-radiological spectrum, causes, and optimum investigation strategy are not established. We reviewed clinical and radiological details of patients with iSS assessed at a specialist neurological center during 2004-2016 using predefined standardized radiological criteria. All imaging findings were rated blinded to clinical details. We identified 65 patients with iSS, whom we classified into 2 groups: type 1 (classical) and type 2 (secondary) iSS. Type 1 (classical) iSS included 48 patients without any potentially causal radiologically confirmed single spontaneous or traumatic intracranial hemorrhage, of whom 39 (83%) had hearing loss, ataxia, or myelopathy; type 2 (secondary) iSS included 17 patients with a potentially causal radiologically confirmed spontaneous or traumatic intracranial hemorrhage, of whom none had hearing loss, ataxia, or myelopathy. Of the patients with type 1 (classical) iSS, 40 (83%) had a potentially causal cranial or spinal dural abnormality, 5 (11%) had an alternative cause, and 3 (6%) had no cause identified. Intra-arterial digital subtraction angiography did not identify any underlying causal lesions for type 1 iSS. Type 1 (classical) iSS, defined using simple radiological criteria, is associated with a characteristic neurological syndrome. Rational investigation, including spinal MRI, nearly always reveals a potential cause, most often a dural abnormality. Catheter angiography appears to be unhelpful, suggesting that classical iSS is not associated with macrovascular arterial pathology. Recognition of type 1 (classical) iSS should allow timely diagnosis and early consideration of treatment. Ann Neurol 2017;81:333-343.

Primary care perceptions of neurology and neurology services.

BACKGROUND: Neurophobia (fear of neural sciences) and evaluation of independent sector contracts in neurology have seldom been examined among general practitioners (GPs). METHODS: A questionnaire determined GPs' perceptions of neurology compared with other medical specialties. GP experiences of neurology services with independent sector companies and the local National Health Service (NHS) were compared. Areas of potential improvement in NHS neurology services were recorded from thematic analyses. RESULTS: Among 76 GPs neurology was perceived to be as interesting as other medical specialties. GPs reported less knowledge, more difficulty and less confidence in neurology compared with other medical specialties. There was a preference for a local NHS neurology service (p<0.001), which was easier to contact (p<0.001) and provided better follow-up. GPs reported that local neurology services provided better patient satisfaction. CONCLUSIONS: GPs prefer local NHS neurology services to independent sector contracts. GPs' evaluations should inform commissioning of neurology services. Combating neurophobia should be an integral part of responsive commissioning.

Stroke Laterality Bias in the Management of Acute Ischemic Stroke.

BACKGROUND: Little is known of the impact of stroke laterality on the management process and outcome of patients with acute ischemic stroke (AIS). METHODS: Consecutive patients admitted to a general hospital over 1 year with supratentorial AIS were eligible for inclusion in the study. Baseline characteristics and risk factors, delays in hospital admission, imaging, intrahospital transfer to an acute stoke unit, stroke severity and classification, length of hospital admission, as well as 10-year mortality were measured and compared among right and left hemisphere AIS patients. RESULTS: There were 141 patients (77 men, 64 women; median age 73 [interquartile range 63-79] years), There were 71 patients with left hemisphere AIS and 70 with right hemisphere AIS. Delays to hospital admission from stroke onset to neuroimaging were similar among right and left hemisphere AIS patients. Delay in transfer to an acute stroke unit (ASU) following hospital admission was on average 14 hours more for right hemisphere compared to left hemisphere AIS patients (P = .01). Laterality was not associated with any difference in 10-year survival. CONCLUSIONS: Patients with mild and nondominant AIS merit particular attention to minimize their intrahospital transfer time to an ASU.

Idiopathic Intracranial Hypertension in the Northwest of Northern Ireland: Epidemiology and Clinical Management.

BACKGROUND: There is limited literature on the epidemiology of idiopathic intracranial hypertension (IIH). The diagnosis and management of IIH require a multidisciplinary approach. We sought to study the incidence as well as prevalence of IIH and to evaluate the current management of IIH in the northwest of Northern Ireland. METHODS: Medical records of patients diagnosed with IIH between 2007 and 2014 in a general hospital in Northern Ireland were reviewed. Clinical and outcome data were retrieved. RESULTS: There were 45 patients with IIH, 44 women: 1 man. The mean age at presentation was 29.4 (SD 9.8) years and mean body mass index (BMI) 39.8 (SD 9.5) kg/ m(2). All patients had neuroimaging, 44 (98%) had CT/MR venogram and 41 (91%) had visual perimetry. The crude incidence of IIH was 2.36 per 100,000 (95% CI 1.65-3.37). For women, the incidence was 4.65 per 100,000/year (95% CI 3.25-6.66). The prevalence was 14.3 per 100,000 overall (95% CI 9.72-20.9) but 28.1 per 100,000 in women (95% CI 19.2-41.2). Visual field defects were identified in 25 of 41 (61%); 4 patients (9%) required shunting procedures. At follow-up, the mean BMI decreased by 1.6 kg/m(2) (p = 0.024). CONCLUSIONS: The incidence of IIH in the northwest of Northern Ireland is among the highest ever reported and probably reflects the known increase in obesity.

Clinical and diagnostic findings in patients with elevated cerebrospinal bilirubin.

INTRODUCTION: Cerebrospinal fluid (CSF) spectroscopy can identify subarachnoid haemorrhage (SAH) when CT is negative in patients presenting with acute severe headache. The primary objective of this study was to evaluate the clinical use and usefulness of CSF spectrophotometry. Secondary objectives were to identify other causes of elevated CSF bilirubin, to analyse headache descriptions and to compare clinical features in patients with an elevated CSF bilirubin among those with and without an intracranial vascular cause of SAH (avSAH). METHODS: Consecutive patients admitted to two hospitals in Enniskillen and Londonderry between 1 January 2004 and 30 September 2014 with CSF spectroscopy bilirubin results were identified from a clinical chemistry laboratory dataset. Patients with elevated CSF bilirubin were studied. Clinical demographics, delays to investigation and final diagnoses were recorded. Patients with avSAH were compared with patients without avSAH. RESULTS: Among 1813 patients with CSF spectrophotometry results, requests increased more than threefold during the study (p<0.001). Fifty-six patients had elevated CSF bilirubin. Ten (17.9%) had avSAH, of which 8 (14.3%) had aneurysmal SAH. Non-vascular causes of elevated CSF bilirubin included meningitis, spontaneous intracranial hypotension and carcinomatous meningitis. Headache descriptions varied. Time from headache onset to admission, CT scan and lumbar puncture did not differ significantly for patients with avSAH and non-avSAH. CSF red cell counts were higher among patients with avSAH than patients with non-avSAH (p=0.005). CONCLUSIONS: CSF bilirubin measurement has an important role in identifying avSAH in CT-negative patients presenting with a thunderclap headache. Better clinical selection of patients is required as CSF spectrophotometry, although sensitive, is not specific for SAH.

An unusual cause of hemifacial spasm.

Hemifacial spasm is not an infrequent presentation and a vascular loop is commonly implicated. Cerebellopontine angle (CPA) lesions are uncommon but can be excluded with appropriate imaging. There have been only around 150 case reports of CPA lipoma; hemifacial spasm has been associated only in eight cases. We present an additional case and discuss the literature and management.

A quality improvement programme with a specialist nurse in a neurovascular clinic.

AIMS AND OBJECTIVES: To measure the impact of a quality improvement programme with a stroke specialist nurse and increased capacity at neurovascular clinics. BACKGROUND: Transient ischaemic attack and minor stroke are medical emergencies prompting urgent assessment and treatment. Delays in specialist assessment and management are frequent and may increase stroke risk. DESIGN: Pre- and post evaluation of intervention. METHODS: All patients referred to a neurovascular clinic were recorded during two phases: 2006-2008 and 2010-2012. For the 2010-2012 period, a stroke specialist nurse contacted all patients with appointment details, provided driving advice and asked for an eyewitness to attend the clinic. Diagnosis, delay in specialist assessment, prevalence of transient ischaemic attack/minor stroke as confirmed at the clinic and compliance with UK driving regulations were measured and compared before and after this intervention. RESULTS: A total of 1327 patients were assessed in the two study phases. Referrals to the neurovascular service increased without a decrease in the prevalence of transient ischaemic attack/minor stroke. Delays from clinical event to assessment were decreased for referrals from 36·5-13 days, and adherence to the UK driving restrictions improved for confirmed transient ischaemic attack/minor stroke patients from 61-94%. Fewer patients failed to attend a neurovascular appointment arranged by the stroke specialist nurse than those who failed a general neurology appointment arranged by partial booking. CONCLUSIONS: This quality improvement programme reduced delays for all referred patients, improved compliance with driving regulations and demonstrated efficient use of neurovascular clinic spaces. Increasing local capacity may unmask more transient ischaemic attack/minor stroke patients. RELEVANCE TO CLINICAL PRACTICE: A stroke nurse can help improve the efficiency of a neurovascular clinic and improve patient safety with driving advice.

Two different presentations, one diagnosis.

Acute confusion and hyponatraemia are common presentations in acute medicine. We report two cases of anti-voltage gated potassium channel (VGKC) antibody-related limbic encephalitis highlighting the variable presentation of this condition. Both patients were thoroughly investigated with MRI scan of brain, lumbar puncture, EEG as well as infective and autoimmune screens for encephalitis. Anti-VGKC antibodies were positive for both patients and prompt treatment with immunotherapy yielded good recovery. Patients presenting with confusion and seizures who have no demonstrable infectious or metabolic cause should have investigation for an autoimmune cause expedited. In addition, psychiatric presentations with atypical features such as drowsiness should prompt similar investigations. The outcome of anti-VGKCrelated limbic encephalitis is improved with early treatment employing steroids or immunotherapy.

Bariatric surgery tourism in the COVID-19 era.

Background: Since the start of the Covid-19 pandemic primary and secondary health care services in Northern Ireland have observed an increase in the number of patients who have had bariatric surgery outside of the UK. This study sought to estimate the frequency of bariatric surgery tourism and to audit indications, blood monitoring and medical complications. Methods: All primary care centres within the Western Health Social Care Trust (WHSCT) were invited to document the number of patients undergoing bariatric surgery between January 1, 2017 and December 31, 2022. For one primary care centre, patients who underwent bariatric surgery were assessed against the National Institute of Health and Clinical Excellence (NICE) guideline indications for bariatric surgery. In addition, the blood monitoring of these patients was audited against the British Obesity and Metabolic Surgery Society (BOMSS) guidelines for up to two years following surgery. Medical contacts for surgical complications of bariatric surgery were recorded. Results: Thirty-five of 47 (74.5%) GP surgeries replied to the survey, representing 239,961 patients among 325,126 registrations (73.8%). In the six year study period 463 patients had reported having bariatric surgery to their GP. Women were more likely to have had bariatric surgery than men (85.1% versus 14.9%). There was a marked increase in the number of patients undergoing bariatric surgery with each year of the study (p<0.0001 chi square for trend). Twenty-one of 47 patients (44.7%) evaluated in one primary care centre fulfilled NICE criteria for bariatric surgery. The level of three-month monitoring ranged from 23% (for vitamin D) to 89% (electrolytes), but decreased at two years to 9% (vitamin D) and 64% (electrolytes and liver function tests). Surgical complication prevalence from wound infections was 19% (9 of 44). Antidepressant medications were prescribed for 23 of 47 patients (48.9%). Conclusions: The WHSCT has experienced a growing population of patients availing of bariatric surgery outside of the National Health Service. In view of this and the projected increase in obesity prevalence, a specialist obesity management service is urgently required in Northern Ireland.

Serum Neurofilaments in Motor Neuron Disease and Their Utility in Differentiating ALS, PMA and PLS.

Neurofilament levels are elevated in many neurodegenerative diseases and have shown promise as diagnostic and prognostic biomarkers in Amyotrophic Lateral Sclerosis (ALS), the most common form of Motor Neuron Disease (MND). This study assesses serum neurofilament light (NFL) and neurofilament heavy (NFH) chain concentrations in patients with ALS, other variants of motor neuron disease such as Progressive Muscular Atrophy (PMA) and Primary Lateral Sclerosis (PLS), and a range of other neurological diseases. It aims to evaluate the use of NFL and NFH to differentiate these conditions and for the prognosis of MND disease progression. NFL and NFH levels were quantified using electrochemiluminescence immunoassays (ECLIA). Both were elevated in 47 patients with MND compared to 34 patients with other neurological diseases and 33 healthy controls. NFL was able to differentiate patients with MND from the other groups with a Receiver Operating Characteristic (ROC) curve area under the curve (AUC) of 0.90 (p < 0.001). NFL correlated with the rate of disease progression in MND (rho 0.758, p < 0.001) and with the ALS Functional Rating Scale (rho -0.335, p = 0.021). NFL levels were higher in patients with ALS compared to both PMA (p = 0.032) and PLS (p = 0.012) and were able to distinguish ALS from both PMA and PLS with a ROC curve AUC of 0.767 (p = 0.005). These findings support the use of serum NFL to help diagnose and differentiate types of MND, in addition to providing prognostic information to patients and their families.

Systematic Review and Meta-Analysis of Diagnostic Agreement in Suspected TIA.

OBJECTIVE: To determine the interrater variability for TIA diagnostic agreement among expert clinicians (neurologists/stroke physicians), administrative data, and nonspecialists. METHODS: We performed a meta-analysis of studies from January 1984 to January 2019 using MEDLINE, EMBASE, and PubMed. Two reviewers independently screened for eligible studies and extracted interrater variability measurements using Cohen's kappa scores to assess diagnostic agreement. RESULTS: Nineteen original studies consisting of 19,421 patients were included. Expert clinicians demonstrate good agreement for TIA diagnosis (κ = 0.71, 95% confidence interval [CI] = 0.62-0.81). Interrater variability between clinicians' TIA diagnosis and administrative data also demonstrated good agreement (κ = 0.68, 95% CI = 0.62-0.74). There was moderate agreement (κ = 0.41, 95% CI = 0.22-0.61) between referring clinicians and clinicians at TIA clinics receiving the referrals. Sixty percent of 748 patient referrals to TIA clinics were TIA mimics. CONCLUSIONS: Overall agreement between expert clinicians was good for TIA diagnosis, although variation still existed for a sizeable proportion of cases. Diagnostic agreement for TIA decreased among nonspecialists. The substantial number of patients being referred to TIA clinics with other (often neurologic) diagnoses was large, suggesting that clinicians, who are proficient in managing TIAs and their mimics, should run TIA clinics.

A Neurodisparity Index of Nationwide Access to Neurological Health Care in Northern Ireland.

Nationwide disparities in managing neurological patients have rarely been reported. We compared neurological health care between the population who reside in a Health and Social Care Trust with a tertiary neuroscience center and those living in the four non-tertiary center Trusts in Northern Ireland. Using the tertiary center Trust population as reference, neurodisparity indices (NDIs) defined as the number of treated patients resident in each Trust per 100,000 residents compared to the same ratio in the tertiary center Trust for a fixed time period. NDIs were calculated for four neurological pathways-intravenous thrombolysis (iv-tPA) and mechanical thrombectomy (MT) for acute ischemic stroke (AIS), disease modifying treatment (DMT) in multiple sclerosis (MS) and admissions to a tertiary neurology ward. Neurological management was recorded in 3,026 patients. Patients resident in the tertiary center Trust were more likely to receive AIS treatments (iv-tPA and MT) and access to the neurology ward (p < 0.001) than patients residing in other Trusts. DMT use for patients with MS was higher in two non-tertiary center Trusts than in the tertiary center Trust. There was a geographical gradient for MT for AIS patients and ward admissions. Averaged NDIs for non-tertiary center Trusts were: 0.48 (95%CI 0.32-0.71) for patient admissions to the tertiary neurology ward, 0.50 (95%CI 0.38-0.66) for MT in AIS patients, 0.78 (95%CI 0.67-0.92) for iv-tPA in AIS patients, and 1.11 (95%CI 0.99-1.26) for DMT use in MS patients. There are important neurodisparities in Northern Ireland, particularly for MT and tertiary ward admissions. Neurologists and health service planners should be aware that geography and time-dependent management of neurological patients worsen neurodisparities.

Stroke scan agnosia - What radiologists may not see.

OBJECTIVE: Neuroimaging helps neurologists make accurate diagnoses. We used a multidisciplinary review system to search for perceptual discrepancies in stroke lesions. We sought to identify recurrent pitfalls in the detection of neuroimaging stroke lesions. PATIENTS AND METHODS: Patients were selected from a neuroimaging database of second opinions if cerebrovascular lesions had been missed at initial reporting. Patient demographics, scanning modality and stroke type were recorded. RESULTS: A neuroradiologist second opinion was provided for 1336 patients. Forty-four patients, 18 women and 26 men, mean age 59.9 (SD 14.2) years, were identified in whom a vascular lesion was not detected on initial reporting. The lesions included cerebellar infarcts in 17 patients (bilateral in 7), pontine infarction/ischaemia (n=5), pontine and cerebellar lesions (n=1) and spinal infarction (n=1). Supratentorial infarction occurred in 10 patients of which 3 were thalamic infarcts. Vessel abnormalities were present in 8 patients (hyperdense vessel n=3, dissection n=3, middle cerebral artery occlusion on CTA n=1 and cerebral venous sinus thrombosis n=1). Convexity subarachnoid hemorrhage was missed and a subdural hematoma was not identified in one patient. In 10 (23 %) patients the missed lesions occurred solely on CT brain scanning. The missed lesions were symptomatic in 28 (64 %) patients and presentations were acute in 14 (32 %) patients. CONCLUSION: Some cerebrovascular lesions are prone to perceptual errors with CT and MRI brain scanning. Radiologists and neurologists should be aware that posterior fossa lesions (particularly in the cerebellum and pons) and hyperdense vessel signs may be missed. Better identification of radiological cerebrovascular lesions should enhance management of acute and chronic stroke patients.

Country-Wide Analysis of Systemic Factors Associated With Acute Ischemic Stroke Door to Needle Time.

Objective: Pre-hospital, in-hospital, and patient factors are associated with variation in door to needle (DTN) time in acute ischemic stroke (AIS). Publications are usually from large single centers or multicenter registries with less reporting on national results. Materials and methods: All AIS patients treated with intravenous tissue plasminogen activator (iv-tPA) over 4 years (2013-2016) in Northern Ireland were recorded prospectively, including patient demographics, pre-hospital care, thrombolysis rate, and DTN time. Logistic regression was performed to identify factors associated with DTN time. Results: One thousand two hundred and one patients from 10,556 stroke admissions (11.4%) were treated with iv-tPA. Median NIHSS was 10 (IQR 6-17). Median DTN time was 54 min (IQR 36-77) with 61% treated < 60 min from arrival at hospital. National thrombolysis numbers increased over time with improving DTN time (P = 0.002). Arrival method at hospital (ambulance OR 2.3 CI1.4-3.8) pre-alert from ambulance (pre-alert OR = 5.3 CI3.5-8.1) and time of day (out of hours, n = 650, OR 0.20 CI 0.22-0.38) all P < 0.001, were the independent factors in determining DTN time. Variation in DTN time between centers occurred but was unrelated to volume of stroke admissions. Conclusion: Ambulance transport with pre-hospital notification and time of day are associated with shorter DTN time on a national level. Most thrombolysis was delivered outside of normal working hours but these patients are more likely to experience treatment delays. Re-organization of stroke services at a whole system level with emphasis on pre-hospital care and design of stroke teams are required to improve quality and equitable care in AIS nationally.

Vanishing brainstem edema.

Posterior reversible encephalopathy syndrome caused by hypertension is well recognized with magnetic resonance imaging. We report a patient in whom posterior reversible encephalopathy syndrome involved just the brainstem, caused a pontine stroke, and subsequently both clinically and radiologically improved with antihypertensive therapy.

The Edinburgh CT and genetic diagnostic criteria for lobar intracerebral haemorrhage associated with cerebral amyloid angiopathy: model development and diagnostic test accuracy study.

BACKGROUND: 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. METHODS: 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. FINDINGS: 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). INTERPRETATION: 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. FUNDING: UK Medical Research Council, The Stroke Association, and The Wellcome Trust.