Evelyn Teasdale

Magnesium for acute stroke (Intravenous Magnesium Efficacy in Stroke trial): randomised controlled trial

BACKGROUND Magnesium is neuroprotective in animal models of stroke, and findings of small clinical pilot trials suggest potential benefit in people. We aimed to test whether intravenous magnesium sulphate, given within 12 h of stroke onset, reduces death or disability at 90 days. METHODS 2589 patients were randomised within 12h of acute stroke to receive 16 mmol MgSO4 intravenously over 15 min and then 65 mmol over 24 h, or matching placebo. Primary outcome was a global endpoint statistic expressed as the common odds ratio for death or disability at day 90. Secondary outcomes were mortality and death or disability, variously defined as Barthel score less than 95, Barthel score less than 60, and modified Rankin scale more than 1. Predefined subgroup analyses were for the primary endpoint in patients in whom treatment commenced within 6 h versus after 6 h, ischaemic versus non-ischaemic strokes, and cortical stroke syndromes versus non-cortical strokes. Intention-to-treat and efficacy analyses were done. FINDINGS The efficacy dataset included 2386 patients. Primary outcome was not improved by magnesium (odds ratio 0.95, 95% CI 0.80-1.13, p=0.59). Mortality was slightly higher in the magnesium-treated group than in the placebo group (hazard ratio 1.18, 95% CI 0.97-1.42, p=0.098). Secondary outcomes did not show any treatment effect. Planned subgroup analyses showed benefit of magnesium in non-cortical strokes (p=0.011) whereas greater benefit had been expected in the cortical group. INTERPRETATION Magnesium given within 12 h of acute stroke does not reduce the chances of death or disability significantly, although it may be of benefit in lacunar strokes.

Pituitary apoplexy and its effect on vision.

A series of 15 patients with a clinical diagnosis of pituitary apoplexy is reviewed. Clinical features are highlighted, with stress on the defects of visual function and ocular motility, and the associated endocrine abnormalities are described. Potential diagnostic errors and their significance are considered. The incidence of this complication in a large series of pituitary adenoma patients is measured, and the radiological and pathological findings are recorded. The results of treatment by surgery and/or radiotherapy and/or bromocriptine are assessed, particularly in relation to visual consequences, and compared with previous reports in the literature, which are reviewed.

What Constitutes a True Hyperdense Middle Cerebral Artery Sign

Objectives: The ‘hyperdense MCA sign’ refers to an appearance of increased attenuation of the proximal middle cerebral artery (MCA) that is often associated with thrombosis of the M1 MCA segment and may be the only diagnostic feature on computed tomography early after ischaemic stroke. False positives are recognized, and correct recognition of this sign has, therefore, assumed greater importance with the advent of thrombolytic therapy for stroke. We sought to define objective criteria for hyperdensity of the MCA. Methods: Brain computed tomographs obtained by a standard protocol in a neuroradiology department were analyzed by a single observer. All consecutive scans reported as exhibiting a hyperdense MCA were compared to controls reported as having normal scans. Ovoid regions of interest were placed over the vessels and cerebral cortices, and the attenuation in Hounsfield units (HU) measured. Absolute attenuation and ratios of one side to the other were compared. Results: MCA attenuation was unrelated to age in cases (n = 18) and controls (n = 80). The mean MCA attenuation was greater in the affected MCA of cases as compared with controls [54.0 HU (99% confidence interval CI 46.7–61.2) vs. 41.3 HU (99% CI 39.7–43.0); p < 0.00001]. Cases were subdivided into true and false positives by the ratio of denser:less dense MCA (within or without the 95% prediction interval for controls). In all true positives, the MCA ratio was > 1.2. 9 of 10 true positives had acute ischaemic stroke; 1 patient had herpes simplex encephalitis, but had MCA attenuation within the 95% CI for controls. False positives had mature cerebral infarction or non-ischaemic pathologies. The ratio of MCA attenuation to adjacent cerebral cortex was significantly higher in both true and false positives than in controls. Conclusions: Hyperdense MCAs associated with acute ischaemic stroke can be distinguished from normal vessels and false positives by measurement of absolute attenuation of affected and normal vessels: an absolute density of >43 HU and a MCA ratio of >1.2 defined hyperdensity and excluded all other pathologies. Confirmation in other centres is required.

Early Recurrent Ischemic Stroke Complicating Intravenous Thrombolysis for Stroke Incidence and Association With Atrial Fibrillation

Background and Purpose— Mechanisms of early neurologic deterioration after treatment with intravenous, recombinant, tissue-type plasminogen activator (IV rt-PA) include symptomatic intracerebral hemorrhage (SICH) and early recurrent ischemic stroke. We observed a number of cases of acute deterioration due to recurrent ischemic events. Methods— We undertook a single-center, retrospective analysis of consecutive acute stroke patients treated with IV rt-PA between January 2006 and December 2008 to define the incidence of early neurologic deterioration (≥4-point drop on the National Institutes of Health Stroke Scale within 72 hours) and its mechanism. Deterioration was attributed to SICH when associated with a PH1 or PH2 hemorrhage on postdeterioration computed tomography scans, to recurrent ischemic stroke when there was clinical and radiologic evidence of a new territorial infarction or new vessel occlusion, and otherwise to evolution of the incident stroke. Results— Of 228 consecutive IV rt-PA-treated patients, 34 (15%) developed early neurologic deterioration, 18 (8%) secondary to incident strokes 10 (4.4%) due to SICH, and 6 (2.6%) due to early recurrent ischemic events, which were significantly associated with atrial fibrillation (present in 5 of 6 patients; 4 paroxysmal, 1 permanent). In 4 patients, sudden clinical deterioration developed during or shortly after IV rt-PA infusion, and in 2, deterioration developed 3 days later. All died 2 days to 2 weeks later. The single case without atrial fibrillation had a recurrent, contralateral, middle cerebral artery stroke during IV rt-PA infusion and multiple high-signal emboli detected by transcranial Doppler. Early recurrent ischemic stroke accounted for 5 of 12 (42%) cases of early neurologic deterioration in patients with atrial fibrillation. Conclusion— In this single-center series, the incidence of early recurrent ischemic stroke after IV rt-PA was 2.6% and was associated with previous atrial fibrillation.

Visual evaluation of perfusion computed tomography in acute stroke accurately estimates infarct volume and tissue viability

Objective: To establish the validity of visual interpretation of immediately processed perfusion computed tomography (CT) maps in acute stroke for prediction of final infarction. Methods: Perfusion CT studies acquired prospectively were reprocessed within six hours of stroke onset using standard CT console software. Four contiguous 5 mm thick images were obtained and maps of time to peak (TTP) and cerebral blood volume (CBV) generated. Volumes of lesions identified only by visual inspection were measured from manually drawn regions of interest. Volumes of tissue with prolonged TTP or reduced CBV were compared with independently calculated volume of infarction on non-contrast CT (NCCT) at 24–48 hours, and with clinical severity using the NIHSS score. Arterial patency at 24–48 h was included in analyses. Results: Studies were analysed from 17 patients 150 minutes (median) after stroke onset. Volume of tissue with prolonged TTP correlated with initial NIHSS (r = 0.62, p = 0.009), and with NCCT final infarct volume when arterial occlusion persisted (r = 0.953, p = 0.012). Volume of tissue with reduced CBV correlated with final infarct volume if recanalisation occurred (r = 0.835, p = 0.001). Recanalisation was associated with lower 24 h NIHSS score (6 (IQR, 5 to 9.5) v 19 (18 to 26), p = 0.027), and in 10 patients given rtPA for MCA M1 occlusion, with lower infarct volume (73 v 431 ml, p = 0.002). Conclusions: Visual evaluation of TTP and CBV maps generated by standard perfusion CT software correlated with 24–48 hour CT infarct volumes. Comparison of TTP and CBV maps yields information on tissue viability. Perfusion CT represents a practical technique to aid acute clinical decision making. Recanalisation was a crucial determinant of clinical and radiological outcome.

Pituitary microadenomas. Does Gadolinium enhance their demonstration

SummaryTen patients with biochemical evidence of a hormonally active pituitary adenoma were examined by dynamic contrast enhanced computed tomography (CT) and then by pre and post Gadolinium-DTPA (Gd-DTPA) enhanced magnetic resonance imaging (MRI). Excluding one false positive case, CT and unenhanced MRI were comparable in the detection of microadenoma. Post Gd-DTPA examination gave more clear evidence of the actual adenoma in two patients and aided in the demonstration of a third. However, in two others all imaging techniques failed to demonstrate the microadenoma subsequently found at surgery. On the post enhancement MRI it was easier to assess the relationship of a tumour to the cavernous sinus and to visualise the relationships of the parasellar carotid arteries.

Serial ventricular volume measurements: further insights into the aetiology and pathogenesis of benign intracranial hypertension.

Ventricular volumes have been measured from CT scans of patients with benign intracranial hypertension both at initial presentation and at a later date. Volumes initially were smaller than normal, but at review five patients showed a significant increase in ventricular size. Persisting small ventricular volume correlated with persisting symptoms and signs and with persisting obesity. This supports the view that patients with benign intracranial hypertension have brain swelling and that obesity may be implicated in the pathogenesis, perhaps via a neuroendocrine disturbance. It is suggested that weight reduction may be an important component of treatment.

Spontaneous closure of an intracranial middle cerebral arteriovenous fistula

SummaryThis case report concerns the spontaneous closure of a middle cerebral arteriovenous fistula, lesions which are normally treated by surgery or interventional therapy. We have been unable to find any previous report of spontaneous closure of a similar fistula.

Impact of GP direct-access computerised tomography for the investigation of chronic daily headache.

BACKGROUND Chronic daily headache is a major healthcare problem, with significant resource implications for specialist services. Since 1999, GPs in Greater Glasgow have had direct access to computerised tomography (CT) for investigation of chronic daily headache. AIM The purpose of this study is to assess the significance of pathology, impact of the service, and GP satisfaction. METHOD The direct-access CT findings in patients between 1999 and 2007 were reviewed. Radiological reports were reviewed for abnormal findings by a radiologist. A neurologist reviewed those cases with abnormalities to assess their potential causation in presenting symptoms. A questionnaire was sent to the referring GP for every patient referred for direct-access CT. Data from the Information Services Division of NHS National Services Scotland was used to estimate potential cost benefits. RESULTS A total of 4404 CT scans were performed. Abnormal findings were reported in 461 (10.5%), and the reported abnormalities were considered a potential causative factor for the presenting symptoms in 60 patients (1.4%). Other abnormalities mostly resulted from established cerebrovascular disease and atrophy; 986 GP questionnaires were analysed. The major body of GP opinion (n = 460, 47%) indicated that direct-access CT was their preferred choice for referral of chronic daily headache. If direct-access CT was not available, neurology (n = 448, 45%) and general medicine (n = 379, 38%) would be the commonest referral choices. This study also reveals that 86% did not require further specialist referral. Projecting the GP questionnaire data to the study group gave an approximate cost saving of at least £86 681.81. CONCLUSION Direct-access CT is now the preferred choice of management for patients with chronic daily headache in primary care. Patients and GPs are reassured by a normal scan in the majority of cases. There may be cost savings, although confirmation of cost-effectiveness would require further study.

The role of non-invasive computed tomography in patients with suspected dural fistulas with spinal drainage.

OBJECTIVE:Accurate diagnosis and demonstration of the angioarchitecture and localization of a spinal dural arteriovenous fistula is of crucial importance before treatment. Selective spinal angiography (DSA) has been considered the standard technique, but is invasive, time-consuming, and may be falsely negative. This report evaluates the use of noninvasive vascular imaging (computed tomographic and magnetic resonance angiography [MRA]) in patients suspected to have a dural fistula with spinal drainage. METHOD:Ten consecutive patients had DSA and multidetector computed tomographic angiography (MDCTA), eight also had MRA. Nine were men with an average age of 67 years. In nine patients, the diagnosis was confirmed at surgery or intravascular treatment. Eight were proven to have a spinal dural fistula. In two, the fistula was within the cervical cranial dura. In all patients, the venous drainage involved only the spinal venous plexus. RESULTS:MDCTA identified the level of the feeding artery in nine patients. In two cases, selective DSA failed to show the abnormality found on MDCTA, but both were confirmed at surgery. MRA was diagnostic in a case in which the lesion was not accurately depicted by either MDCTA or DSA. MRA was less accurate than MDCTA in determining the level of the feeding artery. CONCLUSION:MDCTA and MRA can direct and focus DSA. MDCTA gives additional useful three-dimensional bone detail and localization information for the surgeon. It may replace DSA if surgery is the planned treatment.