Automatic segmentation of white matter hyperintensities from brain magnetic resonance images in the era of deep learning and big data - A systematic review.

BACKGROUND: White matter hyperintensities (WMH), of presumed vascular origin, are visible and quantifiable neuroradiological markers of brain parenchymal change. These changes may range from damage secondary to inflammation and other neurological conditions, through to healthy ageing. Fully automatic WMH quantification methods are promising, but still, traditional semi-automatic methods seem to be preferred in clinical research. We systematically reviewed the literature for fully automatic methods developed in the last five years, to assess what are considered state-of-the-art techniques, as well as trends in the analysis of WMH of presumed vascular origin. METHOD: We registered the systematic review protocol with the International Prospective Register of Systematic Reviews (PROSPERO), registration number - CRD42019132200. We conducted the search for fully automatic methods developed from 2015 to July 2020 on Medline, Science direct, IEE Explore, and Web of Science. We assessed risk of bias and applicability of the studies using QUADAS 2. RESULTS: The search yielded 2327 papers after removing 104 duplicates. After screening titles, abstracts and full text, 37 were selected for detailed analysis. Of these, 16 proposed a supervised segmentation method, 10 proposed an unsupervised segmentation method, and 11 proposed a deep learning segmentation method. Average DSC values ranged from 0.538 to 0.91, being the highest value obtained from an unsupervised segmentation method. Only four studies validated their method in longitudinal samples, and eight performed an additional validation using clinical parameters. Only 8/37 studies made available their methods in public repositories. CONCLUSIONS: We found no evidence that favours deep learning methods over the more established k-NN, linear regression and unsupervised methods in this task. Data and code availability, bias in study design and ground truth generation influence the wider validation and applicability of these methods in clinical research.

Hyperdense artery sign, symptomatic infarct swelling and effect of alteplase in acute ischaemic stroke.

BACKGROUND: Alteplase improves functional outcomes of patients with acute ischaemic stroke, but its effects on symptomatic infarct swelling, an adverse complication of stroke and the influence of CT hyperdense artery sign (HAS) are unclear. This substudy of the Third International Stroke Trial aimed to investigate the association between HAS and symptomatic infarct swelling and effect of intravenous alteplase on this association. METHODS: We included stroke patients whose prerandomisation scan was non-contrast CT. Raters, masked to clinical information, assessed baseline (prerandomisation) and follow-up (24-48 hours postrandomisation) CT scans for HAS, defined as an intracranial artery appearing denser than contralateral arteries. Symptomatic infarct swelling was defined as clinically significant neurological deterioration ≤7 days after stroke with radiological evidence of midline shift, effacement of basal cisterns or uncal herniation. RESULTS: Among 2961 patients, HAS presence at baseline was associated with higher risk of symptomatic infarct swelling (OR 2.21; 95% CI 1.42 to 3.44). Alteplase increased the risk of swelling (OR 1.69; 95% CI 1.11 to 2.57), with no difference between patients with and those without baseline HAS (p=0.49). In patients with baseline HAS, alteplase reduced the proportion with HAS at follow-up (OR 0.67; 95% CI 0.50 to 0.91), where HAS disappearance was associated with reduced risk of swelling (OR 0.25, 95% CI 0.14 to 0.47). CONCLUSION: Although alteplase was associated with increased risk of symptomatic infarct swelling in patients with or without baseline HAS, it was also associated with accelerated clearance of HAS, which in return reduced swelling, providing further mechanistic insights to underpin the benefits of alteplase.

Effect of IV alteplase on the ischemic brain lesion at 24-48 hours after ischemic stroke.

OBJECTIVE: To determine whether alteplase alters the development of ischemic lesions on brain imaging after stroke. METHODS: The Third International Stroke Trial (IST-3) was a randomized controlled trial of IV alteplase for ischemic stroke. We assessed CT or brain MRI at baseline (pretreatment) and 24 to 48 hours posttreatment for acute lesion visibility, extent, and swelling, masked to all other data. We analyzed associations between treatment allocation, change in brain tissue appearances between baseline and follow-up imaging, and 6-month functional outcome in IST-3. We performed a meta-analysis of randomized trials of alteplase vs control with pre- and postrandomization imaging. RESULTS: Of 3,035 patients recruited in IST-3, 2,916 had baseline and follow-up brain imaging. Progression in either lesion extent or swelling independently predicted poorer 6-month outcome (adjusted odds ratio [OR] = 0.92, 95% confidence interval [CI] 0.88-0.96, p < 0.001; OR = 0.73, 95% CI 0.66-0.79, p < 0.001, respectively). Patients allocated alteplase were less likely than controls to develop increased lesion visibility at follow-up (OR = 0.77, 95% CI 0.67-0.89, p < 0.001), but there was no evidence that alteplase reduced progression of lesion extent or swelling. In meta-analysis of 6 trials including IST-3 (n = 4,757), allocation to alteplase was associated with a reduction in ischemic lesion extent on follow-up imaging (OR = 0.85, 95% CI 0.76-0.95, p = 0.004). CONCLUSION: Alteplase was associated with reduced short-term progression in lesion visibility. In meta-analysis, alteplase reduced lesion extent. These findings may indicate that alteplase improves functional outcome by reducing tissue damage. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that IV alteplase impedes the progression of ischemic brain lesions on imaging after stroke.

Arterial Obstruction on Computed Tomographic or Magnetic Resonance Angiography and Response to Intravenous Thrombolytics in Ischemic Stroke.

BACKGROUND AND PURPOSE: Computed tomographic angiography and magnetic resonance angiography are used increasingly to assess arterial patency in patients with ischemic stroke. We determined which baseline angiography features predict response to intravenous thrombolytics in ischemic stroke using randomized controlled trial data. METHODS: We analyzed angiograms from the IST-3 (Third International Stroke Trial), an international, multicenter, prospective, randomized controlled trial of intravenous alteplase. Readers, masked to clinical, treatment, and outcome data, assessed prerandomization computed tomographic angiography and magnetic resonance angiography for presence, extent, location, and completeness of obstruction and collaterals. We compared angiography findings to 6-month functional outcome (Oxford Handicap Scale) and tested for interactions with alteplase, using ordinal regression in adjusted analyses. We also meta-analyzed all available angiography data from other randomized controlled trials of intravenous thrombolytics. RESULTS: In IST-3, 300 patients had prerandomization angiography (computed tomographic angiography=271 and magnetic resonance angiography=29). On multivariable analysis, more extensive angiographic obstruction and poor collaterals independently predicted poor outcome (P<0.01). We identified no significant interaction between angiography findings and alteplase effect on Oxford Handicap Scale (P≥0.075) in IST-3. In meta-analysis (5 trials of alteplase or desmoteplase, including IST-3, n=591), there was a significantly increased benefit of thrombolytics on outcome (odds ratio>1 indicates benefit) in patients with (odds ratio, 2.07; 95% confidence interval, 1.18-3.64; P=0.011) versus without (odds ratio, 0.88; 95% confidence interval, 0.58-1.35; P=0.566) arterial obstruction (P for interaction 0.017). CONCLUSIONS: Intravenous thrombolytics provide benefit to stroke patients with computed tomographic angiography or magnetic resonance angiography evidence of arterial obstruction, but the sample was underpowered to demonstrate significant treatment benefit or harm among patients with apparently patent arteries. CLINICAL TRIAL REGISTRATION: URL: http://www.isrctn.com. Unique identifier: ISRCTN25765518.

Switching patients with acromegaly from octreotide to pasireotide improves biochemical control: crossover extension to a randomized, double-blind, Phase III study.

BACKGROUND: Many patients with acromegaly do not achieve biochemical control with first-generation somatostatin analogues. A large, multicenter, randomized, Phase III core study demonstrated that pasireotide LAR had significantly superior efficacy over octreotide LAR. This analysis explores the efficacy and safety of switching therapeutic arms in inadequately controlled patients during a 12-month crossover extension. METHODS: Patients with inadequate biochemical control (GH ≥2.5 µg/L and/or IGF-1 > ULN) at end of core study (month 12) were eligible to switch to pasireotide LAR 40 mg/28 days (n = 81) or octreotide LAR 20 mg/28 days (n = 38). One dose escalation to pasireotide LAR 60 mg/28 days or octreotide LAR 30 mg/28 days was permitted, but not mandatory, at month 17 or 20. RESULTS: Twelve months after crossover, 17.3 % of pasireotide LAR and 0 % of octreotide LAR patients achieved GH <2.5 µg/L and normal IGF-1 (main outcome measure); 27.2 and 5.3 % of pasireotide LAR and octreotide LAR patients achieved normal IGF-1, respectively; 44.4 and 23.7 % of pasireotide LAR and octreotide LAR patients achieved GH <2.5 µg/L, respectively. Mean (±SD) tumor volume further decreased from the end of the core study by 25 % (±25) and 18 % (±28); 54.3 % of pasireotide LAR and 42.3 % of octreotide LAR patients achieved significant (≥20 %) tumor volume reduction during the extension. The safety profile of pasireotide LAR was similar to that of octreotide LAR, with the exception of the frequency and degree of hyperglycemia-related adverse events. CONCLUSIONS: Pasireotide LAR is a promising treatment option for patients with acromegaly inadequately controlled with the first-generation somatostatin analogue octreotide LAR. TRIAL REGISTRATION: clinicaltrials.gov, NCT00600886 . Registered 14 January 2008.

Effect of alteplase on the CT hyperdense artery sign and outcome after ischemic stroke.

OBJECTIVE: To investigate whether the location and extent of the CT hyperdense artery sign (HAS) at presentation affects response to IV alteplase in the randomized controlled Third International Stroke Trial (IST-3). METHODS: All prerandomization and follow-up (24-48 hours) CT brain scans in IST-3 were assessed for HAS presence, location, and extent by masked raters. We assessed whether HAS grew, persisted, shrank, or disappeared at follow-up, the association with 6-month functional outcome, and effect of alteplase. IST-3 is registered (ISRCTN25765518). RESULTS: HAS presence (vs absence) independently predicted poor 6-month outcome (increased Oxford Handicap Scale [OHS]) on adjusted ordinal regression analysis (odds ratio [OR] 0.66, p < 0.001). Outcome was worse in patients with more (vs less) extensive HAS (OR 0.61, p = 0.027) but not in proximal (vs distal) HAS (p = 0.420). Increasing age was associated with more HAS growth at follow-up (OR 1.01, p = 0.013). Treatment with alteplase increased HAS shrinkage/disappearance at follow-up (OR 0.77, p = 0.006). There was no significant difference in HAS shrinkage with alteplase in proximal (vs distal) or more (vs less) extensive HAS (p = 0.516 and p = 0.580, respectively). There was no interaction between presence vs absence of HAS and benefit of alteplase on 6-month OHS (p = 0.167). CONCLUSIONS: IV alteplase promotes measurable reduction in HAS regardless of HAS location or extent. Alteplase increased independence at 6 months in patients with and without HAS. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients within 6 hours of ischemic stroke with a CT hyperdense artery sign, IV alteplase reduced intra-arterial hyperdense thrombus.

Hemispheric association and dissociation of voice and speech information processing in stroke.

As we listen to someone speaking, we extract both linguistic and non-linguistic information. Knowing how these two sets of information are processed in the brain is fundamental for the general understanding of social communication, speech recognition and therapy of language impairments. We investigated the pattern of performances in phoneme versus gender categorization in left and right hemisphere stroke patients, and found an anatomo-functional dissociation in the right frontal cortex, establishing a new syndrome in voice discrimination abilities. In addition, phoneme and gender performances were most often associated than dissociated in the left hemisphere patients, suggesting a common neural underpinnings.

Consent for Brain Tissue Donation after Intracerebral Haemorrhage: A Community-Based Study.

BACKGROUND: Spontaneous intracerebral haemorrhage is a devastating form of stroke and its incidence increases with age. Obtaining brain tissue following intracerebral haemorrhage helps to understand its cause. Given declining autopsy rates worldwide, the feasibility of establishing an autopsy-based collection and its generalisability are uncertain. METHODS: We used multiple overlapping sources of case ascertainment to identify every adult diagnosed with intracerebral haemorrhage between 1st June 2010-31st May 2012, whilst resident in the Lothian region of Scotland. We sought consent from patients with intracerebral haemorrhage (or their nearest relative if the patient lacked mental capacity) to conduct a research autopsy. RESULTS: Of 295 adults with acute intracerebral haemorrhage, 110 (37%) could not be approached to consider donation. Of 185 adults/relatives approached, 91 (49%) consented to research autopsy. There were no differences in baseline demographic variables or markers of intracerebral haemorrhage severity between consenters and non-consenters. Adults who died and became donors (n = 46) differed from the rest of the cohort (n = 249) by being older (median age 80, IQR 76-86 vs. 75, IQR 65-83, p = 0.002) and having larger haemorrhages (median volume 23 ml, IQR 13-50 vs. 13 ml, IQR 4-40; p = 0.002). CONCLUSIONS: Nearly half of those approached consent to brain tissue donation after acute intracerebral haemorrhage. The characteristics of adults who gave consent were comparable to those in an entire community, although those who donate early are older and have larger haemorrhage volumes.

Influence of intracerebral hemorrhage location on incidence, characteristics, and outcome: population-based study.

BACKGROUND AND PURPOSE: The characteristics of intracerebral hemorrhage (ICH) may vary by ICH location because of differences in the distribution of underlying cerebral small vessel diseases. Therefore, we investigated the incidence, characteristics, and outcome of lobar and nonlobar ICH. METHODS: In a population-based, prospective inception cohort study of ICH, we used multiple overlapping sources of case ascertainment and follow-up to identify and validate ICH diagnoses in 2010 to 2011 in an adult population of 695 335. RESULTS: There were 128 participants with first-ever primary ICH. The overall incidence of lobar ICH was similar to nonlobar ICH (9.8 [95% confidence interval, 7.7-12.4] versus 8.6 [95% confidence interval, 6.7-11.1] per 100 000 adults/y). At baseline, adults with lobar ICH were more likely to have preceding dementia (21% versus 5%; P=0.01), lower Glasgow Coma Scale scores (median, 13 versus 14; P=0.03), larger ICHs (median, 38 versus 11 mL; P<0.001), subarachnoid extension (57% versus 5%; P<0.001), and subdural extension (15% versus 3%; P=0.02) than those with nonlobar ICH. One-year case fatality was lower after lobar ICH than after nonlobar ICH (adjusted odds ratio for death at 1 year: lobar versus nonlobar ICH 0.21; 95% confidence interval, 0.07-0.63; P=0.006, after adjustment for known predictors of outcome). There were 4 recurrent ICHs, which occurred exclusively in survivors of lobar ICH (annual risk of recurrent ICH after lobar ICH, 11.8%; 95% confidence interval, 4.6%-28.5% versus 0% after nonlobar ICH; log-rank P=0.04). CONCLUSIONS: The baseline characteristics and outcome of lobar ICH differ from other locations.

Observer reliability of CT angiography in the assessment of acute ischaemic stroke: data from the Third International Stroke Trial.

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.

Long-term efficacy and safety of subcutaneous pasireotide in acromegaly: results from an open-ended, multicenter, Phase II extension study.

Pasireotide has a broader somatostatin receptor binding profile than other somatostatin analogues. A 16-week, Phase II trial showed that pasireotide may be an effective treatment for acromegaly. An extension to this trial assessed the long-term efficacy and safety of pasireotide. This study was an open-label, single-arm, open-ended extension study (primary efficacy and safety evaluated at month 6). Patients could enter the extension if they achieved biochemical control (GH ≤ 2.5 µg/L and normal IGF-1) or showed clinically relevant improvements during the core study. Thirty of the 60 patients who received pasireotide (200-900 µg bid) in the core study entered the extension. At extension month 6, of the 26 evaluable patients, six were biochemically controlled, of whom five had achieved control during the core study. Normal IGF-1 was achieved by 13/26 patients and GH ≤ 2.5 µg/L by 12/26 at month 6. Nine patients received pasireotide for ≥24 months in the extension; three who were biochemically controlled at month 24 had achieved control during the core study. Of 29 patients with MRI data, nine had significant (≥20%) tumor volume reduction during the core study; an additional eight had significant reduction during the extension. The most common adverse events were transient gastrointestinal disturbances; hyperglycemia-related events occurred in 14 patients. Twenty patients had fasting plasma glucose shifted to a higher category during the extension. However, last available glucose measurements were normal for 17 patients. Pasireotide has the potential to be an effective, long-term medical treatment for acromegaly, providing sustained biochemical control and significant reductions in tumor volume.

CT and Clinical Predictors of Fatigue at One Month after Stroke.

BACKGROUND: Fatigue is a common and distressing consequence of stroke, and the aetiology of post-stroke fatigue (PSF) is poorly understood. It is unclear whether chronic brain changes [cerebral atrophy and white matter lesions (WML)], stroke lesion location or certain clinical features are related to its development. The aim of this study was to identify, in patients with acute stroke, whether features in different brain regions on routine CT imaging or routinely collected clinical features predicted PSF at 1 month. METHODS: In total, 107 patients (62% male) with acute ischaemic or haemorrhagic stroke were assessed for fatigue (Fatigue Assessment Scale), anxiety and depression (Hospital Anxiety and Depression Scale) at 1 month. Admission brain CT was rated using a structured scoring system for (i) severity of atrophy and (ii) severity of WML in different regions of the brain, and (iii) site of acute and previous vascular lesions. RESULTS: Cerebral atrophy of mild or greater severity was present in 84 patients (77.5%) and WML of mild or greater severity was present in 54 patients (50.5%) in at least one of the evaluated brain regions. There was no association between PSF and severity of atrophy or WML, or presence of acute or previous vascular lesions. We used the Oxfordshire Community Stroke Project (OCSP) classification to explore the possible influence of lesion location because a minority of the patients (37.4%) had visible acute lesions. Fatigue scores were higher in patients with clinically diagnosed posterior strokes (p = 0.046), in females (p = 0.05) and in those with higher depression and anxiety scores (ρ = 0.52; p < 0.001 and ρ = 0.49; p < 0.001, respectively). Structural CT variables were not significant predictors of fatigue (log FAS) in a linear regression which controlled for age, sex, pre-stroke fatigue, OCSP classification, depression and anxiety. The significant predictors of fatigue were depression (ß = 0.30; p = 0.007) and anxiety (ß = 0.28; p = 0.013; adjusted R(2) = 0.254). Stroke subtype (according to the OCSP classification) was marginally predictive (ß = 0.17; p = 0.05) and sex was not statistically significant (ß = 0.15; p = 0.08). CONCLUSIONS: Features on routine post-stroke CT do not appear to associate with fatigue at 1 month. However, clinically diagnosed posterior strokes as well as female gender, anxiety and depression may be linked with fatigue. Therefore, clinical vigilance rather than CT features should be used to predict fatigue early after stroke. Further research is needed in this area to establish whether biological mechanisms underlie the development of PSF.

Use of dynamic contrast-enhanced MRI to measure subtle blood-brain barrier abnormalities.

There is growing interest in investigating the role of subtle changes in blood-brain barrier (BBB) function in common neurological disorders and the possible use of imaging techniques to assess these abnormalities. Some studies have used dynamic contrast-enhanced MR imaging (DCE-MRI) and these have demonstrated much smaller signal changes than obtained from more traditional applications of the technique, such as in intracranial tumors and multiple sclerosis. In this work, preliminary results are presented from a DCE-MRI study of patients with mild stroke classified according to the extent of visible underlying white matter abnormalities. These data are used to estimate typical signal enhancement profiles in different tissue types and by degrees of white matter abnormality. The effect of scanner noise, drift and different intrinsic tissue properties on signal enhancement data is also investigated and the likely implications for interpreting the enhancement profiles are discussed. No significant differences in average signal enhancement or contrast agent concentration were observed between patients with different degrees of white matter abnormality, although there was a trend towards greater signal enhancement with more abnormal white matter. Furthermore, the results suggest that many of the factors considered introduce uncertainty of a similar magnitude to expected effect sizes, making it unclear whether differences in signal enhancement are truly reflective of an underlying BBB abnormality or due to an unrelated effect. As the ultimate aim is to achieve a reliable quantification of BBB function in subtle disorders, this study highlights the factors which may influence signal enhancement and suggests that further work is required to address the challenging problems of quantifying contrast agent concentration in healthy and diseased living human tissue and of establishing a suitable model to enable quantification of relevant physiological parameters. Meanwhile, it is essential that future studies use an appropriate control group to minimize these influences.

A large web-based observer reliability study of early ischaemic signs on computed tomography. The Acute Cerebral CT Evaluation of Stroke Study (ACCESS).

BACKGROUND: Early signs of ischaemic stroke on computerised tomography (CT) scanning are subtle but CT is the most widely available diagnostic test for stroke. Scoring methods that code for the extent of brain ischaemia may improve stroke diagnosis and quantification of the impact of ischaemia. METHODOLOGY AND PRINCIPAL FINDINGS: We showed CT scans from patients with acute ischaemic stroke (n = 32, with different patient characteristics and ischaemia signs) to doctors in stroke-related specialties world-wide over the web. CT scans were shown twice, randomly and blindly. Observers entered their scan readings, including early ischaemic signs by three scoring methods, into the web database. We compared observers' scorings to a reference standard neuroradiologist using area under receiver operator characteristic curve (AUC) analysis, Cronbach's alpha and logistic regression to determine the effect of scales, patient, scan and observer variables on detection of early ischaemic changes. Amongst 258 readers representing 33 nationalities and six specialties, the AUCs comparing readers with the reference standard detection of ischaemic signs were similar for all scales and both occasions. Being a neuroradiologist, slower scan reading, more pronounced ischaemic signs and later time to CT all improved detection of early ischaemic signs and agreement on the rating scales. Scan quality, stroke severity and number of years of training did not affect agreement. CONCLUSIONS: Large-scale observer reliability studies are possible using web-based tools and inform routine practice. Slower scan reading and use of CT infarct rating scales improve detection of acute ischaemic signs and should be encouraged to improve stroke diagnosis.

Blood-brain barrier permeability in Alzheimer's disease: a case-control MRI study.

Blood-brain barrier (BBB) dysfunction may contribute to the risk of Alzheimer's disease (AD). Dynamic contrast-enhanced magnetic resonance imaging (MRI) was performed repeatedly nine times before and up to 30 min following a 20 ml Gd-DTPA bolus injection in 15 AD participants and 15 healthy older people. For each participant, small circular regions of interest (size: 9 voxels) were placed to sample widely the deep gray matter (12 regions), cortical gray matter (72 regions), white matter (72 regions) and CSF (8 regions) as well as the basilar and internal carotid arteries (3 regions). Data were analysed using mixed effects models. There was no overall significant difference for AD subjects versus controls, but there was a significant effect for the time-by-AD interaction. Estimated marginal means remained essentially unchanged in AD subjects, but increased slowly after 15 min in healthy controls. An initial rise in gray matter MRI signal intensity followed by a later increase was also seen in AD participants after adjusting for CSF MRI signal intensities. The data suggest that BBB permeability is present even at an early stage of AD. Though the extent of leakage was no greater than that of non-demented people of a similar age in this small sample, the temporal pattern differed, indicating different blood-brain-CSF compartmental kinetics.

Associations between diffusion and perfusion parameters, N-acetyl aspartate, and lactate in acute ischemic stroke.

BACKGROUND AND PURPOSE: In acute ischemic stroke, the amount of neuronal damage in hyperintense areas on MR diffusion imaging (DWI) is unclear. We used spectroscopic imaging to measure N-acetyl aspartate (NAA, a marker of normal neurons) and lactate (a marker of ischemia) to compare with diffusion and perfusion values in the diffusion lesion in acute ischemic stroke. METHODS: We recruited patients with acute ischemic stroke prospectively and performed MR diffusion weighted (DWI), perfusion, and spectroscopic imaging. We coregistered the images, outlined the visible diffusion lesion, and extracted metabolite, perfusion, and apparent diffusion coefficient (ADC) values from the diffusion lesion. RESULTS: 42 patients were imaged, from 1.5 to 24 hours after stroke. In the DWI lesion, although NAA was reduced, there was no correlation between NAA and ADC or perfusion values. However, raised lactate correlated with reduced ADC (Spearman rho=0.32, P=0.04) and prolonged mean transit time (MTT, rho=0.31, P=0.04). Increasing DWI lesion size was associated with lower NAA and higher lactate (rho=-0.44, P=0.003; rho=0.49, P=0.001 respectively); NAA fell with increasing times to imaging (rho=-0.3, P=0.03), but lactate did not change. CONCLUSIONS: Although larger confirmatory studies are needed, the correlation of ADC and MTT with lactate but not NAA suggests that ADC and MTT are better markers of the presence of ischemia than of cumulative neuronal loss. Further studies should define more precisely the rate of neuronal loss and relationship to diffusion and perfusion parameters with respect to the depth and duration of ischemia.

Octreotide LAR vs. surgery in newly diagnosed patients with acromegaly: a randomized, open-label, multicentre study.

OBJECTIVE: This prospective randomized study evaluated the efficacy and safety of octreotide LAR vs. surgery in newly diagnosed acromegalic patients. METHODS: Totally 104 male and female patients were enrolled in a 50-week, exploratory, open-label and randomized study. Eligible patients were randomized to receive either octreotide LAR 20 mg every 28 days or to undergo surgery. Efficacy was assessed by changes in mean GH and IGF-I serum concentrations, at weeks 12, 24 and 48. Tumour volume was assessed by contrast-enhanced MRI. In both groups, treatment adjustment was performed for patients uncontrolled at week 12 or 24. Octreotide LAR patients received a dose increased to 30 mg or, if already receiving this dose, investigator and patients could decide to cross-over to surgery. Patients uncontrolled after surgery received octreotide LAR 20 mg, increased to 30 mg if acromegaly was still uncontrolled. RESULTS: Overall success rates at weeks 24 and 48 were 25% and 28% for the octreotide LAR group and 49% and 39% for the surgery group. Only the difference observed at week 24 was statistically significant (P = 0.047). Both groups had a significant (> 20%) tumour shrinkage: 73% of patients in the octreotide LAR group and 95% in the surgery group. Major differences between octreotide LAR and surgery group in the occurrence of adverse events were gastrointestinal (71%vs. 27%), hepatobiliary (41%vs. 8%) and respiratory (5%vs. 28%). CONCLUSION: This first randomized study in unselected patients indicates that the 48-week treatment outcome of octreotide LAR as first-line treatment of acromegaly does not significantly differ from surgery. As a complete response to surgery in GH-secreting macro-adenomas can be difficult, first-line therapy with octreotide LAR can be considered as a viable alternative for most patients with acromegaly, due to its low complication rate.

Blood-brain barrier: ageing and microvascular disease--systematic review and meta-analysis.

Cerebral "microvascular" disease occurs in lacunar stroke, leukoaraiosis, vascular dementia and Alzheimer's disease. It may arise from or contribute to insidious damage to the blood-brain barrier (BBB). We systematically reviewed the literature for evidence that BBB permeability is altered in patients with manifestations of cerebral microvascular disease. We found 31 BBB permeability studies (1953 individuals) of normal ageing or cerebral microvascular disease. In healthy humans, increasing age (10 comparisons, controls(C):subjects(S)=357:336) was associated with increased BBB permeability (standardised mean difference (S.M.D.) 1.21, 95% confidence interval (CI) 0.60, 1.81, p<0.01). BBB permeability was increased further in patients with either vascular or Alzheimer's dementia compared with age-matched controls (26 comparisons, C:S=510:547, S.M.D. 0.81, 99% CI 0.37, 1.26, p<0.01); in vascular compared with Alzheimer's dementia (10 comparisons, C:S=291:165, S.M.D. 0.71, 99% CI 0.12, 1.29, p<0.01); and with worsening leukoaraiosis (5 comparisons, C:S=122:88, S.M.D. 0.60, 99% CI 0.30, 0.89, p<0.01). BBB permeability increases with normal ageing and may be an important mechanism in the initiation or worsening of cerebral microvascular disease. Further studies on the role of BBB permeability are urgently needed.

A prospective, multicentre study to investigate the efficacy, safety and tolerability of octreotide LAR (long-acting repeatable octreotide) in the primary therapy of patients with acromegaly.

OBJECTIVE: To evaluate the efficacy, safety and tolerability of octreotide LAR (long-acting repeatable octreotide) in the primary therapy of acromegaly. DESIGN AND PATIENTS: Ninety-eight previously untreated acromegalics were recruited into this prospective multicentre study. A total of 68 patients successfully completed 48 weeks of the study period, received 12 doses of octreotide LAR 10-30 mg every 4 weeks, and constituted the population used for this analysis. MEASUREMENTS AND RESULTS: A clinically relevant reduction (i.e. to < or = 5 microg/l) in mean GH (mGH) was recorded in 72% of patients after 24 weeks of treatment, and 42% reached a 'safe' GH value (< or = 2.5 microg/l). At week 48, 16 more patients were considered partial GH responders (GH > 2.5 microg/l and < or = 5 microg/l) and 44% had reached a GH level < or = 2.5 microg/l. IGF-1 levels normalized in 38% and 34% of patients after 24 and 48 weeks of treatment, respectively. At study completion, 10 patients (14.7%) who had not normalized their IGF-1 levels had achieved at least a 50% decrement in this marker. In eight microadenoma patients, tumour volume decreased from a mean baseline level of 298 +/- 145 mm3 to 139 +/- 94 mm3 after 24 weeks and to 99 +/- 70 mm3 after 48 weeks of therapy. In 60 patients with macroadenoma, the corresponding values were 3885 +/- 5077 mm3 at baseline and 2723 +/- 3435 and 2406 +/- 3207 mm3 after 24 and 48 weeks, respectively. At weeks 24 and 48, a significant (> 20%) tumour volume reduction was reported in 63% and 75% of patients, respectively. A reduction in the severity of symptoms of acromegaly was observed early in treatment and was maintained throughout the study period. CONCLUSION: Octreotide LAR represents a viable alternative to surgery for primary treatment of acromegaly leading to a progressive regression of tumour volume, a sustained control of biochemical abnormalities and an adequate relief of symptoms of the disease.

Factors influencing the detection of early CT signs of cerebral ischemia: an internet-based, international multiobserver study.

BACKGROUND AND PURPOSE: Early CT signs of cerebral ischemia are subtle. Little is known of which factors influence the detection of infarct signs. We compared neuroradiologists' scan readings with those of other specialists involved in the care of stroke patients. METHODS: We used the Internet to show 63 CT scans, all acquired <6 hours after stroke and representing different patient ages, times to scanning, stroke severity, and early CT signs of ischemia to physicians involved in stroke care. They completed a structured scan interpretation proforma over the Internet. We compared the detection of early ischemic signs stratified by severity and the effect of prior stroke between different specialties. RESULTS: Among 207 observers, neuroradiologists saw significantly more of "any early ischemic changes" than did stroke physicians, general radiologists, geriatricians, or neurologists (all P<0.0001), predominantly due to neuroradiologists' greater detection of "mild" hypoattenuation or swelling. Detection of "severe" hypoattenuation or swelling, and hyperattenuated arteries did not differ between specialties. Old infarcts impaired recognition of early ischemic signs. Non-neuroradiologists did not "over-call" signs. Years of scan-reading experience did not account for these differences, but neuroradiologists took, on average, 30 seconds longer to read each scan than did most other specialists (P<0.0001). CONCLUSIONS: Non-neuroradiologists should realize that they are unlikely to over-call signs, that old infarcts may distract them from seeing early ischemic signs, and read stroke CT scans more slowly, as these factors may help them perform more like neuroradiologists.