Brain herniation on computed tomography is a poor predictor of whether patients with a devastating brain injury can be confirmed dead using neurological criteria.

Background: It is unclear if the presence of compartmental brain herniation on neuroimaging should be a prerequisite to the clinical confirmation of death using neurological criteria. The World Brain Death Project has posed this as a research question. Methods: The final computed tomography of the head scans before death of 164 consecutive patients confirmed dead using neurological criteria and 41 patients with devastating brain injury who died following withdrawal of life sustaining treatment were assessed by a neuroradiologist to compare the incidence of herniation and other features of cerebral swelling. Results: There was no difference in the incidence of herniation in patients confirmed dead using neurological criteria and those with devastating brain injury (79% vs 76%, OR 1.23 95%, CI 0.56-2.67). The sensitivity and specificity of brain herniation in patients confirmed dead using neurological criteria was 79% and 24%, respectively. The positive and negative predictive value was 81% and 23%, respectively. The most sensitive computed tomography of the head findings for death using neurological criteria were diffuse sulcal effacement (93%) and basal cistern effacement (91%) and the most specific finding was loss of grey-white differentiation (80%). The only features with a significantly different incidence between the death using neurological criteria group and the devastating brain injury group were loss of grey-white differentiation (46 vs 20%, OR 3.56, 95% CI 1.55-8.17) and presence of contralateral ventricular dilatation (24 vs 44%, OR 0.41, 95% CI 0.20-0.84). Conclusions: Neuroimaging is essential in establishing the cause of death using neurological criteria. However, the presence of brain herniation or other signs of cerebral swelling are poor predictors of whether a patient will satisfy the clinical criteria for death using neurological criteria or not. The decision to test must remain a clinical one.

A Meta-Analysis of Observational Evidence for the Use of Endovascular Thrombectomy in Proximal Occlusive Stroke Beyond 6 Hours in Patients with Limited Core Infarct.

PURPOSE: The safety and efficacy of endovascular thrombectomy (EVT) for patients with proximal occlusive stroke presenting beyond 6 hours and selected on the basis of favorable neuroimaging remains unclear. MATERIALS AND METHODS: A systematic search was performed from four electronic databases from their inception to Jan 2017. A meta-analysis of outcomes from studies with patients treated beyond 6 hours was compared to those treated within the established 6 hour therapeutic window in randomized trials, selected using conventional imaging methods with CT/CT angiography. RESULTS: A total of 8 articles met inclusion criteria for the study population (a prospective single-center study, 5 retrospective single-center studies and 2 retrospective multicenter studies). These were compared to the results of three prospective trials of patients treated within 6 hours selected using CT/CT angiography. For patients treated >6 hours and <6 hours respectively, the weighted mean age was 64.7 vs. 67.0 years; the presenting NIHSS was 15.7 vs. 17.1 and the time from symptom onset to puncture was 4.0 hours vs. 15.1 hours. Weighted pooled estimates of successful recanalization (TIMI 2/3 or TICI 2b/3) and favorable outcome (mRS ≤2) were similar between both groups, 70.1% vs. 70.6%, P=0.75 and 38.9% vs. 38.4%, P=0.88 respectively. Pooled mortality measured at 3 months was 22.8% for those treated >6 hours and 12.5% for <6 hours, P<0.0001. Symptomatic intracranial hemorrhage was not significantly different (10.0% vs. 7.7%, P=0.33). CONCLUSION: When compared to established methods of patient selection, EVT employed beyond 6 hours in those selected with imaging to exclude large core infarcts achieves similar rates of recanalization, and functional outcome but there is a significant increase in mortality despite no increase in symptomatic intracranial hemorrhage.

Meta-analysis of stent-assisted coiling versus coiling-only for the treatment of intracranial aneurysms.

Endovascular coil embolization is a widely accepted and useful treatment modality for intracranial aneurysms. However, the principal limitation of this technique is the high aneurysm recurrence. The adjunct use of stents for coil embolization procedures has revolutionized the field of endovascular aneurysm management, however its safety and efficacy remains unclear. Two independent reviewers searched six databases from inception to July 2015 for trials that reported outcomes according to those who received stent-assisted coiling versus coiling-only (no stent-assistance). There were 14 observational studies involving 2698 stent-assisted coiling and 29,388 coiling-only patients. The pooled immediate occlusion rate for stent-assisted coiling was 57.7% (range: 20.2%-89.2%) and 48.7% (range: 31.7%-89.2%) for coiling-only, with no significant difference between the two (odds ratio [OR}=1.01; 95% confidence intervals [CI}: 0.68-1.49). However, progressive thrombosis was significantly more likely in stent-assisted coiling (29.9%) compared to coiling-only (17.5%) (OR=2.71; 95% CI: 1.95-3.75). Aneurysm recurrence was significantly lower in stent-assisted coiling (12.7%) compared to coiling-only (27.9%) (OR=0.43; 95% CI: 0.28-0.66). In terms of complications, there was no significant difference between the two techniques for all-complications, permanent complications or thrombotic complications. Mortality was significantly higher in the stent-assisted group 1.4% (range: 0%-27.5%) compared to the coiling-only group 0.2% (range: 0%-19.7%) (OR=2.16; 95% CI: 1.33-3.52). Based on limited evidence, stent-assisted coiling shows similar immediate occlusion rates, improved progressive thrombosis and decreased aneurysm recurrence compared to coiling-only, but is associated with a higher mortality rate. Future randomized controlled trials are warranted to clarify the safety of stent-associated coiling.

Endovascular therapy including thrombectomy for acute ischemic stroke: A systematic review and meta-analysis with trial sequential analysis.

One of the primary strategies for the management of acute ischemic stroke is intravenous (IV) thrombolysis with tissue plasminogen activator (t-PA). Over the past decade, endovascular therapies such as the use of stent retrievers to perform mechanical thrombectomy have been found to improve functional outcomes compared to t-PA alone. We aimed to reassess the functional outcomes and complications of IV thrombolysis with and without endovascular treatment for acute ischemic stroke using conventional meta-analysis and trial sequential analysis. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated for the effect of IV thrombolysis with and without endovascular therapy on functional outcome, mortality and symptomatic intracranial hemorrhage (SICH). Trial sequential analysis was done to strengthen the meta-analysis. We analyzed six randomized controlled trials involving 1943 patients. Patients who received IV thrombolysis with endovascular treatment showed significantly higher rates of excellent functional outcomes (modified Rankin Scale [mRS] 0-1) (RR, 1.75 [95% CI, 1.29-2.39]) compared to those who received IV thrombolysis alone. A similar association was seen for good functional outcomes (mRS 0-2) (RR, 1.56 [95% CI, 1.24-1.96]). Trial sequential analysis demonstrated endovascular treatment increased the RR of a good functional outcome by at least 30% compared to IV thrombolysis alone. There was no significant difference in all-cause mortality for mechanical thrombectomy compared to IV thrombolysis alone or the incidence of SICH at 3month follow-up. Endovascular treatment is more likely to result in a better functional outcome for patients compared to IV thrombolysis alone for acute ischemic stroke.

The negative predictive value of CT angiography in the setting of perimesencephalic subarachnoid hemorrhage.

BACKGROUND: Perimesencephalic subarachnoid hemorrhage (PMSAH) is only rarely associated with a ruptured cerebral aneurysm and CT angiography (CTA) has very good sensitivity and specificity for aneurysm detection. The necessity for invasive imaging with digital subtraction angiography (DSA) is therefore debatable. We chose to assess the negative predictive value (NPV) of CTA in a series of patients with PMSAH treated at our institution over a 9-year period. METHODS: We retrospectively assessed the diagnostic yield of DSA after initial negative CTA in patients with a PMSAH pattern defined as blood centered anterior to the midbrain and/or pons within the pre-pontine or interpeduncular cistern with possible quadrigeminal or ambient cistern extension; possible extension into the basal parts of the sylvian fissures but not the lateral sylvian fissures; possible extension to the cisterna magna but not centered on the cisterna magna; and possible extension into the fourth ventricle and occipital horns of the lateral ventricles. RESULTS: Using this definition of PMSAH, of 72 patients, one patient showed a potentially significant finding on DSA that was not demonstrated on initial CTA (NPV 98.61% (95% CI 92.47% to 99.77%)). However, when cisterna magna extension was excluded from the definition of PMSAH, no false negative CTAs in 56 patients were encountered (NPV 100% (95% CI 93.56% to 100.00%)). CONCLUSIONS: The NPV of normal CTA for an arterial abnormality in patients with PMSAH is high and our results therefore question the role of invasive imaging. The findings also suggest that a prospective study designed to clarify the necessity of performing DSA in this population would be feasible.

Short term outcomes following clipping and coiling of ruptured intracranial aneurysms: does some of the benefit of coiling stem from less procedural impact on deranged physiology at presentation?

BACKGROUND: Endovascular coiling (EVC) has been shown to yield superior clinical outcomes to surgical clipping (SC) in the treatment of ruptured cerebral aneurysms. The reasons for these differences remain obscure. We aimed to assess outcomes of EVC and SC relative to baseline physiological derangement. METHODS: This was an exploratory analysis of prospectively collected trial data. Physiological derangement was assessed using the Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring system. Other contributory variables such as age, World Federation of Neurosurgical Societies (WFNS) grade, and development of complications, including hydrocephalus and vasospasm, were included in the analysis. Clinical outcome was independently assessed at 90 days using the modified Rankin Scale (mRS). Hospital stay, ventilated days, and total norepinephrine dose were also used as secondary outcomes. Multivariate analysis was performed using binary logistic regression. RESULTS: EVC was performed in 69 patients and SC in 66 patients. More profound physiological derangement (APACHE II score >15) was the strongest predictor of poor outcome in the overall cohort (OR 17.80, 95% CI 4.78 to 66.21, p<0.0001). For those with more deranged physiology (APACHE II score>15; 59 patients), WFNS grade ≥4 (OR 6.74, 1.43 to 31.75) and SC (OR 6.33, 1.27 to 31.38) were significant predictors of poor outcome (p<0.05). Favorable outcome (mRS 0-2) was seen in 11% of SC patients compared with 38% of EVC patients in this subgroup. SC patients had significantly increased total norepinephrine dose, ventilated days, and hospital stay (p<0.05). CONCLUSIONS: More profound physiological derangement at baseline is a strong predictor of eventual poor outcome, and outcomes for patients with more profound baseline physiological derangement may be improved if undergoing a coiling procedure.

Rates of local procedural-related structural injury following clipping or coiling of anterior communicating artery aneurysms.

BACKGROUND: Surgical clipping and endovascular coiling yield similar functional outcomes for the treatment of saccular aneurysms of the anterior communicating (ACOM) artery. However, surgical treatment may be associated with greater rates of cognitive impairment due to injury of adjacent structures. We aimed to quantify the rates of injury (infarction/hemorrhage) for both clipping and coiling of ACOM aneurysms. METHODS: This was a retrospective dual-center radiological investigation of a consecutive series of patients with ruptured and unruptured ACOM aneurysms treated between January 2011 and October 2014. Post-treatment CT or MRI was assessed for new ischemic or hemorrhagic injury. Injury relating to the primary hemorrhage or vasospasm was differentiated. Univariate analysis using χ(2) tests and multivariate analysis using binary logistic regression was used. RESULTS: 66 patients treated with clipping were compared with 93 patients treated with coiling. 32/66 (48.5%) patients in the clipping group suffered treatment-related injury (31 ischemic, 1 hemorrhagic) compared with 4/93 (4.4%) patients in the coiling group (3 ischemic, 1 hemorrhagic) (p<0.0001). For patients with subarachnoid hemorrhage, the multivariate OR for infarction for clipping over coiling was 24.42 (95% CI 5.84 to 102.14), p<0.0001. The most common site of infarction was the basal forebrain (28/66 patients, 42.4%), with bilateral infarction in 4. There was injury of the septal/subcallosal region in 12/66 patients (18%). CONCLUSIONS: Clipping of ACOM aneurysms is associated with significantly higher rates of structural injury than coiling, and this may be a reason for superior cognitive outcomes in patients treated with coiling in previously published studies.

Endovascular treatment of jugular bulb diverticula causing debilitating pulsatile tinnitus.

We describe the case of a patient who presented with debilitating pulsatile tinnitus in association with two jugular bulb diverticula. The diverticula were treated with stenting of the jugular bulb and coil embolization of the diverticula over two procedures. This resulted in successful resolution of symptoms and at 10 months follow-up the patient is asymptomatic. The technique is discussed with regard to similar published cases and surrogate measures of safety taken from the literature pertaining to idiopathic intracranial hypertension.

Delayed infarction following aneurysmal subarachnoid hemorrhage: Can the role of severe angiographic vasospasm really be dismissed?

BACKGROUND: The recent literature pertaining to delayed cerebral ischemia following aneurysmal subarachnoid hemorrhage has downplayed the role of angiographic vasospasm. However, it is our hypothesis that angiographic vasospasm has a significant pathophysiological role in this disease. We undertook an observational radiographic study of patients who presented in a delayed manner (>72 h from ictus) with evidence of severe angiographic vasospasm on initial angiography in order to describe an apparent association between vasospasm and infarct location. METHODS: This was a retrospective study of consecutive patients treated at our unit. Initial, subsequent, and follow-up cross-sectional imaging with CT or MRI was analyzed in conjunction with initial angiography. Sites of angiographic narrowing, angiographic hypoperfusion, and subsequent sites of infarction were assessed. RESULTS: Thirteen patients (6 women, 7 men) of mean age 49 years were assessed. Mean time to presentation was 6 days. All had severe angiographic vasospasm. Nine of the 13 patients suffered infarction; the infarcts in seven of the nine patients were large. There was correlation between sites of angiographic narrowing and infarction in all cases and eight of the nine cases showed angiographic hypoperfusion in a location corresponding to eventual infarct location. CONCLUSIONS: Severe angiographic vasospasm may be linked to infarction in patients who present late. These infarcts are mostly large despite maximal treatment. We question the notion that proximal vasospasm has a minor role in delayed ischemia.

Endovascular treatment of jugular bulb diverticula causing debilitating pulsatile tinnitus.

We describe the case of a patient who presented with debilitating pulsatile tinnitus in association with two jugular bulb diverticula. The diverticula were treated with stenting of the jugular bulb and coil embolization of the diverticula over two procedures. This resulted in successful resolution of symptoms and at 10 months follow-up the patient is asymptomatic. The technique is discussed with regard to similar published cases and surrogate measures of safety taken from the literature pertaining to idiopathic intracranial hypertension.

Is long-term follow-up of adequately coil-occluded ruptured cerebral aneurysms always necessary? A single-center study of recurrences after endovascular treatment.

PURPOSE: Aneurysm recurrence following coil occlusion is well recognized. However, there is controversy as to how long these patients should be followed up after coiling to detect reopening. We aimed to identify the rate of late reopening and the risk factors for reopening in a large single-center cohort of ruptured aneurysms that appeared adequately occluded at 6 months. We also aimed to assess whether rates of recurrence have altered over time with improving coil and angiographic technology. METHODS: Patients treated between 1996 and 2010 were assessed and those with both 6-month initial and subsequent long-term follow-up with either digital subtraction angiography or magnetic resonance angiography were included. Aneurysms were stratified by features such as size, neck width, anatomical location and time of treatment: 1996-2005 (cohort 1) and 2006-2010 (cohort 2). ORs for risk of recurrence were calculated for aneurysm features and rates of recurrence in each cohort were compared using a χ(2) test. RESULTS: 437 patients with 458 adequately occluded aneurysms at 6 months had mean long-term follow-up of 31 months; 57 (12.4%) were large (≥ 10 mm) and 104 (22.7%) were wide-necked (>4 mm). Nine aneurysms (2%) showed significant late anatomical deterioration whereby retreatment was considered or undertaken. The risk was greater for large aneurysms (≥ 10 mm) (OR 15.61, 95% CI 3.79 to 64.33, p=0.0001) or wide-necked aneurysms (>4 mm) (OR 12.70, 95% CI 2.60 to 62.13, p=0.0017). The frequency of significant late anatomical deterioration and retreatment was also less common in those treated in cohort 2 (p<0.05). No completely occluded aneurysm at 6 months demonstrated significant late recurrence. CONCLUSIONS: Most aneurysms adequately occluded at 6 months did not show evidence of late recurrence. Large and wide-neck aneurysms are, however, at greater risk of later recurrence.

Thrombus length estimation in acute ischemic stroke: a potential role for delayed contrast enhanced CT.

PURPOSE: Thrombus length has been shown to be an important determinant of recanalization using intravenous thrombolysis in hyperacute ischemic stroke. Various studies have attempted to quantify thrombus based on non-contrast CT (NCCT) or CT angiography (CTA). However, thrombus may not be seen on NCCT, and CTA may fail to delineate the distal extent of the thrombus. Contrast enhanced CT (CECT) following CTA can be used to estimate infarct core, but we investigated whether the angiographic data available on these images provided reliable information on thrombus length. MATERIALS AND METHODS: 15 consecutive patients, mean age 81 years (range 63-93), with terminal internal carotid artery or M1-middle cerebral artery occlusions underwent NCCT, CTA (bolus tracked technique), and CECT (acquired 80 s post initial CTA injection). Three radiologists assessed thrombus length on thin slice NCCT, and CTA and CECT. RESULTS: CTA overestimated thrombus length relative to NCCT (p<0.001) and CECT (p<0.001). There was less difference between CTA and CECT estimation in patients with good collateral scores (p<0.05). There was good correlation between NCCT and CECT (Pearson's correlation coefficient=0.90, 95% CI 0.81 to 0.95, p<0.001). Inter-rater reliability assessed using intraclass correlation was 0.95 (95% CI 0.87 to 0.98) for NCCT and 0.98 (95% CI 0.94 to 0.99) for CECT. CONCLUSIONS: CTA regularly overestimates thrombus length as the distal end of the thrombus is not delineated. This can be overcome through the use of a CECT acquisition which can reliably be used to estimate thrombus length.

Endovascular therapy in hyperacute ischaemic stroke: history and current status.

This is a literature review on to the use of endovascular therapy in hyperacute ischaemic stroke secondary to large vessel occlusion (LVO). The prognosis for LVO is generally poor and the efficacy of intravenous tissue plasminogen activator (IV TPA) in the treatment of this subtype of stroke is questionable. It is well documented that recanalisation is associated with improved outcomes but IV TPA has limited efficacy in LVO recanalisation and the complication rates are higher for IV TPA in this stroke subset. Improved recanalisation rates have been demonstrated with intra-arterial TPA and first and second generation mechanical techniques but the rate of favourable outcome has not overtly mirrored this improvement. Several controversial trials using these early techniques have recently been published but fail to reflect modern practice which centres on the use of stent-retriever technology. This has been proven to be superior to older techniques. Not only are recanalisation rates higher, but the speed of recanalisation is greater and clinical results are improved. Multiple observational studies demonstrate consistently high rates of LVO recanalisation; TICI 2b/3 in the order of 65-95% and, rates of favourable outcome (mRS 0-2) in the order of 55% (42.5-77%) in clinically moderate to severe stroke with complicating symptomatic haemorrhage in the order of 1.5-15%. A major factor determining outcome is time to treatment but success has been demonstrated using these devices with bridging therapy, after IV TPA failure or as a stand-alone treatment.

Endovascular treatment of children with cerebral venous sinus thrombosis: a case series.

BACKGROUND: Cerebral venous sinus thrombosis is a potentially serious condition affecting 0.56 to 0.67 per 100,000 children annually; adverse outcomes are common. The standard of care is anticoagulation with heparin. A proportion of patients, however, remain in a severe clinical condition and in these, endovascular therapy is an alternative treatment. There is little published literature on the use of endovascular treatments in children with cerebral venous sinus thrombosis. METHODS: We retrospectively reviewed case notes and imaging in a consecutive series of nine children treated using endovascular therapy after diagnosis of cerebral venous sinus thrombosis. Clinical presentation, decision to escalate therapy, methods of recanalization, and clinical outcome were assessed. RESULTS: Nine children were treated (age range 18 months to 16 years). Diagnosis was made by computed tomography, computed tomography venography, magnetic resonance imaging, or magnetic resonance venography. Seven children were in a coma; one had signs of raised intracranial pressure with progressive cranial nerve palsies; and one was drowsy with a fluctuating hemiparesis. Eight children had been treated with heparin without improvement. Several endovascular methods were used including local tissue plasminogen activator, microguidewire and catheter disruption, balloon angioplasty, and thromboaspiration using the Penumbra device. Eight children had good functional outcomes. One child died as a result of uncontrolled intracranial hypertension secondary to cerebral venous sinus thrombosis. CONCLUSION: Endovascular therapy may have a role in the treatment of cerebral venous sinus thrombosis in children when medical therapy has failed and the patient is in a poor clinical condition.

Neuroimaging in dementia: a practical guide.

Over 800 000 people in the UK are demented. Alzheimer's disease, dementia with Lewy bodies, vascular dementia and frontotemporal lobar degeneration account for the majority. Although detailed clinical assessment forms the basis of evaluating a patient with cognitive impairment, structural and functional imaging techniques are increasingly being used. Neuroimaging can identify changes to supplement the clinical diagnosis and help to distinguish dementia subtypes. This may be important for treatment, prognosis and care planning. Furthermore, early changes on structural and functional imaging may have a role in preclinical detection, perhaps allowing people to start any treatments early. In this review, we explain the tools available to the neuroradiologist and examine the implications of imaging findings in assessing patients with cognitive impairment or dementia.

A rare cause of neural foraminal widening.

The differential diagnosis for lesions causing neural foraminal widening is vast. The majority are solitary benign peripheral nerve sheath tumours, such as neurofibromas or schwannomas. We present a case of a rare cause of neural foraminal expansion secondary to a posterior thoracic extradural angiolipoma. We describe the presence of chemical shift artefact on post gadolinium T1-weighted imaging as indirect evidence of a fatty component. This potentially important diagnostic sign may raise the suspicion of angiolipoma, especially in an isointense or hypointense dumbbell lesion on T1-weighted imaging, and has not been described previously in this context. Accurate radiological diagnosis of an angiolipoma is important to reduce unexpected haemorrhagic complications from biopsy or resection of the lesion.