Perianeurysmal parenchymal cysts - Case series and literature review.

•Intracranial cysts are associated with a number of vascular lesions.•They predominantly occur in larger, partially-thrombosed aneurysms and in older patients.•There is a trend towards enlargement over time if untreated and a likelihood of recurrence following treatment.•We hypothesise the cysts arise either from dilated Virchow-Robin spaces and/or inflammatory processes.

CNS demyelination associated with immune dysregulation and a novel CTLA-4 variant.

BACKGROUND: The cytotoxic T-lymphocyte antigen-4 (CTLA-4) pathway acts as a negative immune regulator of T-cell activation and promotes self-tolerance. CASE: We report the first case of biopsy-proven central nervous system inflammatory demyelination in the context of primary immunodeficiency and a novel CTLA-4 variant. CONCLUSION: This case has significant implications for the development of novel treatments for autoimmune conditions including multiple sclerosis and further emphasises the need for caution with clinical use of CTLA-4 immune checkpoint inhibitors in those with a history of inflammatory demyelination.

Management of incidental unruptured intracranial aneurysms.

The widespread use of MR has led to the increasingly frequent diagnosis of unruptured incidental intracranial aneurysms. Most are small (<7 mm diameter) and will never rupture. Yet, their recognition causes much anxiety, and their optimal management remains controversial. This review addresses the difficulties in managing incidental unruptured saccular intracranial aneurysms. Note that our conclusions and recommendations do not apply to symptomatic unruptured aneurysms or to fusiform, dissecting, mycotic, traumatic and paediatric aneurysms, each of which has a different natural history.

Internal Carotid Artery Test Balloon Occlusion Using Single Photon Emission Computed Tomography Scan in the Management of Complex Cerebral Aneurysms and Skull Base Tumors: A 20-Year Review.

BACKGROUND: Test balloon occlusion (TBO) is important in the management of complex cerebrovascular and skull base lesions when permanent occlusion (PO) of a parent artery may be indicated. Several adjuncts may be used to increase the sensitivity of TBO to predict whether PO will be tolerated. This is an observational study to evaluate the utility of internal carotid artery (ICA) TBO using single photon emission computed tomography (SPECT) scan in the management of complex vascular pathology and skull base tumors. METHODS: All TBO procedures performed over a 20-year period were analyzed. Clinical assessment and angiographic collateral flow were combined with semi-quantitative cerebral blood flow analysis using 99mTc hexamethylpropylene-amine oxime SPECT scan during ICA TBO. Evaluation of collateral circulation after TBO, and the complications of TBO and the safety of PO after successful TBO were evaluated. RESULTS: Eighty-three patients underwent TBO without complication. Of 45 patients with satisfactory TBO, 28 proceeded to PO. Three patients developed transient ischemic symptoms thought to be embolic in origin. Thirty-eight patients had unsatisfactory TBO, of whom 15 required PO accompanied by a bypass procedure. Forty patients in the series did not undergo permanent vessel occlusion. CONCLUSIONS: SPECT scan-enhanced TBO is an important component of the management of complex vascular pathology and skull base tumors, permitting safe PO of the parent vessel and definitive treatment of the main pathology.

Sneddon Syndrome: A Case Report Exploring the Current Challenges Faced with Diagnosis and Management.

Sneddon syndrome (SS) is a rare medium-vessel vasculopathy which characteristically presents with livedo racemosa (LR) and complications such as strokes. This case report describes a female presenting acutely with a stroke and, initially, no evidence of LR. Her antiphospholipid antibodies were negative, and her neuroimaging revealed multiple territory strokes with extensive vasculopathy and fragile neo-formed vessel collateralisation. She had progressive memory loss and multiple transient ischaemic attacks on a background of established infarctions. SS should be considered in any idiopathic medium-vessel vasculopathy despite the absence of LR. Medical therapy can be challenging and the importance of antiphospholipid status in risk stratifying anticoagulation against antiplatelet therapy is discussed with a proposed rheumatology management strategy. The medical option of hydroxychloroquine should be considered in all patients in view of its anti-thrombotic properties and efficacy in diseases such as systemic lupus erythematosus and antiphospholipid syndrome with the suggestion that SS may be a forme fruste of these diseases. Neurosurgical options should be considered for recurrent transient neurological symptoms. For our patient, this included an extracranial to intracranial bypass via a radial artery graft for haemodynamic stroke management confirmed on SPECT imaging. The traditional hallmark of SS has previously been LR. This case highlights an atypical presentation stressing the importance of diagnostic vigilance in a patient with an idiopathic medium-vessel vasculopathy, together with balancing the medical risk of antiplatelet therapy, anticoagulation and thrombolysis whilst revealing possible neurosurgical options in select SS patients.

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.

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.

Tumefactive demyelination presenting during bevacizumab treatment.

We report the emergence of tumefactive demyelination during treatment with intravitreal bevacizumab (Avastin). This is of particular significance given that bevacizumab is currently being assessed as a potential treatment option for neuromyelitis optica, another demyelinating condition.

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.