Aneurysm Treatment With Woven EndoBridge in the Cumulative Population of 3 Prospective, Multicenter Series: 2-Year Follow-Up

BACKGROUND

Woven EndoBridge (WEB; Sequent Medical) treatment is an innovative endovascular approach for treatment of wide-neck bifurcation aneurysms. Initial studies have shown high safety with good efficacy at short term confirmed by trials conducted in United States (WEB-Intrasaccular Therapy) and in Europe (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy [WEBCAST], French Observatory, and WEBCAST-2).

OBJECTIVE

To report the 2-yr clinical and anatomical results of WEB treatment in the combined population of 3 European trials.

METHODS

In a French Observatory, 2-yr clinical and anatomical data were collected. In WEBCAST and WEBCAST-2, 2-yr follow-up was optional, and data were collected when follow-up was performed. Aneurysm occlusion was evaluated using a 3-grade scale: complete occlusion, neck remnant, and aneurysm remnant.

RESULTS

The population for safety was 138/168 patients (82.1%), including 89 females (64.5%), with mean age of 55.5 ± 10.2 yr. The population for efficacy was 121/169 aneurysms (71.6%). Aneurysm locations were middle cerebral artery in 65/121 aneurysms (53.7%), anterior-communicating artery in 25/121 (20.7%), basilar artery in 17/121 (14.0%), and internal carotid artery terminus in 14/121 (11.6%). No clinically relevant adverse events occurred between years 1 and 2. At 2 yr, complete occlusion was observed in 62/121 (51.2%) aneurysms, neck remnant in 36/121 (29.8%) aneurysms, and aneurysm remnant in 23/121 (19.0%) aneurysms. The global retreatment rate at 2 yr was 9.3%.

CONCLUSION

This analysis confirms the high safety profile of WEB treatment at 2 yr. Aneurysm occlusion is generally stable at 2 yr, and the retreatment rate between 1 yr and 2 yr is low (2.0%).

The safety and effectiveness of the Woven EndoBridge (WEB) system for the treatment of wide-necked bifurcation aneurysms: final 12-month results of the pivotal WEB Intrasaccular Therapy (WEB-IT) Study

INTRODUCTION

The Woven EndoBridge Intrasaccular Therapy (WEB-IT) Study is a pivotal, prospective, single-arm, investigational device exemption study designed to evaluate the safety and effectiveness of the WEB device for the treatment of wide-neck bifurcation aneurysms.

METHODS

One-hundred and fifty patients with wide-neck bifurcation aneurysms were enrolled at 21 US and six international centers. Angiograms from the index procedure, and 6-month and 1-year follow-up visits were all reviewed by a core laboratory. All adverse events were reviewed and adjudicated by a clinical events adjudicator. A data monitoring committee provided oversight during the trial to ensure subject safety.

RESULTS

One-hundred and forty-eight patients received the WEB implant. One (0.7%) primary safety event occurred during the study-a delayed ipsilateral parenchymal hemorrhage-on postoperative day 22. No primary safety events occurred after 30 days through 1 year. At the 12-month angiographic follow-up, 77/143 patients (53.8%) had complete aneurysm occlusion. Adequate occlusion was achieved in 121/143 (84.6%) subjects.

CONCLUSIONS

The prespecified safety and effectiveness endpoints for the aneurysms studied in the WEB-IT trial were met. The results of this trial suggest that the WEB device provides an option for patients with wide-neck bifurcation aneurysms that is as effective as currently available therapies and markedly safer.

TRIAL REGISTRATION NUMBER

NCT02191618.

Visualizing artery-specific blood flow patterns above the circle of Willis with vessel-encoded arterial spin labeling

Purpose

To establish the feasibility of using vessel‐encoded pseudocontinuous arterial spin labeling (VEPCASL) for noninvasive vascular territory imaging (VTI) and artery‐specific dynamic angiography of a large number of arterial branches above the circle of Willis within a clinically feasible scan time.

Methods

3D time‐of‐flight angiography was used to select a labeling plane and establish 7 pairs of encoding cycles. These were used for VEPCASL VTI and dynamic 2D angiography (8 min and 3 min acquisition times, respectively) in healthy volunteers, allowing the separation of signals arising from 13 arterial branches (including extracranial arteries) in postprocessing. To demonstrate the clinical potential of this approach, VEPCASL angiography was also applied in 5 patients with brain arteriovenous malformation (AVM).

Results

In healthy volunteers, the artery‐specific filling of the vascular tree and resulting perfusion territories were well depicted. SNRs were approximately 5 times higher than those achievable with single‐artery selective methods. Blood supply to the AVMs was well visualized in all cases, showing the main feeding arteries and venous drainage.

Conclusions

VEPCASL is a highly efficient method for both VTI and dynamic angiography of a large number of arterial branches, providing a comprehensive picture of vascular flow patterns and the effect on downstream tissue perfusion within an acceptable scan time. Automation of labeling plane and vessel‐encoding selection would improve robustness and efficiency, and further refinement could allow quantitative blood flow measurements to be obtained. This technique shows promise for visualizing the blood supply to lesions and collateral flow patterns.

Thrombosis in Cerebral Aneurysms and the Computational Modeling Thereof: A Review

Thrombosis is a condition closely related to cerebral aneurysms and controlled thrombosis is the main purpose of endovascular embolization treatment. The mechanisms governing thrombus initiation and evolution in cerebral aneurysms have not been fully elucidated and this presents challenges for interventional planning. Significant effort has been directed towards developing computational methods aimed at streamlining the interventional planning process for unruptured cerebral aneurysm treatment. Included in these methods are computational models of thrombus development following endovascular device placement. The main challenge with developing computational models for thrombosis in disease cases is that there exists a wide body of literature that addresses various aspects of the clotting process, but it may not be obvious what information is of direct consequence for what modeling purpose (e.g., for understanding the effect of endovascular therapies). The aim of this review is to present the information so it will be of benefit to the community attempting to model cerebral aneurysm thrombosis for interventional planning purposes, in a simplified yet appropriate manner. The paper begins by explaining current understanding of physiological coagulation and highlights the documented distinctions between the physiological process and cerebral aneurysm thrombosis. Clinical observations of thrombosis following endovascular device placement are then presented. This is followed by a section detailing the demands placed on computational models developed for interventional planning. Finally, existing computational models of thrombosis are presented. This last section begins with description and discussion of physiological computational clotting models, as they are of immense value in understanding how to construct a general computational model of clotting. This is then followed by a review of computational models of clotting in cerebral aneurysms, specifically. Even though some progress has been made towards computational predictions of thrombosis following device placement in cerebral aneurysms, many gaps still remain. Answering the key questions will require the combined efforts of the clinical, experimental and computational communities.

Outcome of Nonfunctioning Pituitary Adenomas That Regrow After Primary Treatment: A Study From Two Large UK Centers

CONTEXT

Despite the major risk of regrowth of clinically nonfunctioning pituitary adenomas (CNFAs) after primary treatment, systematic data on the probability of further tumor progression and the effectiveness of management approaches are lacking.

OBJECTIVE

To assess the probability of further regrowth(s), predictive factors, and outcomes of management approaches in patients with CNFA diagnosed with adenoma regrowth after primary treatment.

PATIENTS, DESIGN, AND SETTING

Retrospective cohort study of 237 patients with regrown CNFA managed in two UK centers.

RESULTS

Median follow-up was 5.9 years (range, 0.4 to 37.7 years). The 5-year second regrowth rate was 35.3% (36.2% after surgery; 12.5% after radiotherapy; 12.7% after surgery combined with radiotherapy; 63.4% with monitoring). Of those managed with monitoring, 34.8% eventually were offered intervention. Type of management and sex were risk factors for second regrowth. Among those with second adenoma regrowth, the 5-year third regrowth rate was 26.4% (24.4% after surgery; 0% after radiotherapy; 0% after surgery combined with radiotherapy; 48.3% with monitoring). Overall, patients with a CNFA regrowth had a 4.4% probability of a third regrowth at 5 years and a 10.0% probability at 10 years; type of management of the first regrowth was the only risk factor. Malignant transformation was diagnosed in two patients.

CONCLUSIONS

Patients with regrown CNFA after primary treatment continue to carry considerable risk of tumor progression, necessitating long-term follow-up. Management approach to the regrowth was the major factor determining this risk; monitoring had >60% risk of progression at 5 years, and a substantial number of patients ultimately required intervention.

Safety and Efficacy of Aneurysm Treatment with the WEB: Results of the WEBCAST 2 Study

BACKGROUND AND PURPOSE

Flow disruption with the Woven EndoBridge (WEB) device is an innovative technique for the endovascular treatment of wide-neck bifurcation aneurysms. The initial version of the device (WEB Double-Layer) was evaluated in the WEB Clinical Assessment of IntraSaccular Aneurysm Therapy (WEBCAST) study, whereas the French Observatory study evaluated both WEB Double-Layer and Single-Layer versions of the device. WEBCAST 2 was designed to evaluate the WEB Single-Layer with Enhanced Visualization.

MATERIALS AND METHODS

Patients with wide-neck bifurcation aneurysms for which WEB treatment was possible were included. Clinical data including adverse events and clinical status at 1 month and 1 year were collected and analyzed. A core laboratory evaluated anatomic results at 1 year following the procedure.

RESULTS

Ten European neurointerventional centers included 55 patients (38 women; 27-77 years of age; mean, 54.4 ± 10.0 years) with 55 aneurysms. Aneurysm locations were the middle cerebral artery in 25 aneurysms (45.5%), the anterior communicating artery in 16 (29.1%), the basilar artery in 9 (16.4%), and the internal carotid artery terminus in 5 (9.1%). Procedural morbidity and mortality at 1 month were, respectively, 1.8% (1/55 patients) and 0.0% (0/55 patients). Morbidity and mortality at 1 year were, respectively, 3.9% (2/51 patients) and 2.0% (1/51 patients). At 1 year, complete occlusion was observed in 27/50 aneurysms (54.0%); neck remnant, in 13/50 (26.0%); and aneurysm remnant, in 10/50 (20.0%) (adequate occlusion in 40/50, 80.0%).

CONCLUSIONS

WEBCAST 2 confirms the high safety and efficacy of WEB aneurysm treatment demonstrated in the WEBCAST and French Observatory studies.

Feasibility of Flat Panel Detector CT in Perfusion Assessment of Brain Arteriovenous Malformations: Initial Clinical Experience

The different results from flat panel detector CT in various pathologies have provoked some discussion. Our aim was to assess the role of flat panel detector CT in brain arteriovenous malformations, which has not yet been assessed. Five patients with brain arteriovenous malformations were studied with flat panel detector CT, DSC-MR imaging, and vessel-encoded pseudocontinuous arterial spin-labeling. In glomerular brain arteriovenous malformations, perfusion was highest next to the brain arteriovenous malformation with decreasing values with increasing distance from the lesion. An inverse tendency was observed in the proliferative brain arteriovenous malformation. Flat panel detector CT, originally thought to measure blood volume, correlated more closely with arterial spin-labeling-CBF and DSC-CBF than with DSC-CBV. We conclude that flat panel detector CT perfusion depends on the time point chosen for data collection, which is triggered too early in these patients (ie, when contrast agent appears in the superior sagittal sinus after rapid shunting through the brain arteriovenous malformation). This finding, in combination with high data variability, makes flat panel detector CT inappropriate for perfusion assessment in brain arteriovenous malformations.

Porcine In Vivo Validation of a Virtual Contrast Model: The Influence of Contrast Agent Properties and Vessel Flow Rates

BACKGROUND AND PURPOSE

Accurately and efficiently modeling the transport of angiographic contrast currently offers the best method of verifying computational fluid dynamics simulations and, with it, progress toward the lofty goal of prediction of aneurysm treatment outcome a priori. This study specifically examines the influence of estimated flow rate and contrast properties on such in silico predictions of aneurysm contrast residence and decay.

MATERIALS AND METHODS

Four experimental sidewall aneurysms were created in swine, with aneurysm contrast flow patterns and decay rates observed under angiography. A simplified computational fluid dynamics model of the experimental aneurysm was constructed from 3D angiography and contrast residence predicted a priori. The relative influence of a number of estimated model parameters (contrast viscosity, contrast density, and blood flow rate) on contrast residence was then investigated with further simulations.

RESULTS

Contrast infiltration and washout pattern were accurately predicted by the a priori computational fluid dynamics model; however, the contrast decay rate was underestimated by ∼25%. This error was attributed to the estimated parent vessel flow rate alone, and the effects of contrast viscosity and density on the decay rate were found to be inconsequential. A linear correlation between the parent vessel flow rate and the corresponding contrast decay rate was observed.

CONCLUSIONS

In experimental sidewall aneurysms, contrast fluid properties (viscosity and density) were shown to have a negligible effect on variation in the modeled contrast decay rate. A strong linear correlation was observed between parent vessel flow rate and contrast decay over a physiologically reasonable range of flow rates.

Safety and efficacy of aneurysm treatment with WEB: results of the WEBCAST study

OBJECT

WEB is an innovative intrasaccular treatment for intracranial aneurysms. Preliminary series have shown good safety and efficacy. The WEB Clinical Assessment of Intrasaccular Aneurysm Therapy (WEBCAST) trial is a prospective European trial evaluating the safety and efficacy of WEB in wide-neck bifurcation aneurysms.

METHODS

Patients with wide-neck bifurcation aneurysms for which WEB treatment was indicated were included in this multicentergood clinical practices study. Clinical data including adverse events and clinical status at 1 and 6 months were collected and independently analyzed by a medical monitor. Six-month follow-up digital subtraction angiography was also performed and independently analyzed by a core laboratory. Success was defined at 6 months as complete occlusion or stable neck remnant, no worsening in angiographic appearance from postprocedure, and no retreatment performed or planned.

RESULTS

Ten European neurointerventional centers enrolled 51 patients with 51 aneurysms. Treatment with WEB was achieved in 48 of 51 aneurysms (94.1%). Adjunctive implants (coils/stents) were used in 4 of 48 aneurysms (8.3%). Thromboembolic events were observed in 9 of 51 patients (17.6%), resulting in a permanent deficit (modified Rankin Scale [mRS] Score 1) in 1 patient (2.0%). Intraoperative rupture was not observed. Morbidity (mRS score > 2) and mortality were 2.0% (1 of 51 patients, related to rupture status on entry to study) and 0.0% at 1 month, respectively. Success was achieved at 6 months in 85.4% of patients treated with WEB: 23 of 41 patients (56.1%) had complete occlusion, 12 of 41 (29.3%) had a neck remnant, and 6 of 41 (14.6%) had an aneurysm remnant.

CONCLUSIONS

The WEBCAST study showed good procedural and short-term safety of aneurysm treatment with WEB and good 6-month anatomical results.

Mortality in patients with non-functioning pituitary adenoma is increased: systematic analysis of 546 cases with long follow-up

OBJECTIVE

Non-functioning pituitary adenomas (NFAs) have a prevalence of 7-22/100,000 people. A significant number of patients suffer from morbidities related to the tumor, possible recurrence(s), and treatments utilized. Our aim was to assess mortality of patients with macroNFA and predictive factors.

DESIGN

Retrospective cohort study in a tertiary referral center in the UK.

METHODS

A total of 546 patients operated for a macroNFA between 1963 and 2011 were studied. Mortality data were retrieved through the National Health Service Central Register and hospital records and recorded as standardized mortality ratio (SMR). Mortality was estimated for the total and various subgroups with clinical follow-up data.

RESULTS

Median follow-up was 8 years (range: 1 month-48.5 years). SMR was 3.6 (95% CI, 2.9-4.5), for those operated before 1990, 4.7 (95% CI, 2.7-7.6) and for those after 1990, 3.5 (95% CI, 2.8-4.4). Main causes of death were cardio/cerebrovascular (33.7%), infections (30.1%), and malignancy (28.9%). Cox regression analysis demonstrated that only age at diagnosis remained an independent predictor of mortality (hazard ratio 1.10; 95% CI, 1.07-1.13, P<0.001), whereas sex, presentation with acute apoplexy, extent of tumor removal, radiotherapy, recurrence, untreated GH deficiency, FSH/LH deficiency, ACTH deficiency, TSH deficiency, and treatment with desmopressin had no impact.

CONCLUSIONS

Despite the improvement of treatments over the last three decades, the mortality of patients with NFAs in our series remains high. Apart from age, factors related with the management/outcome of the tumor are not independent predictors, and pituitary hormone deficits managed with the currently-used substitution protocols do not adversely affect mortality.

Time density curve analysis for C-arm FDCT PBV imaging

INTRODUCTION

Parenchymal blood volume (PBV) estimation using C-arm flat detector computed tomography (FDCT) assumes a steady-state contrast concentration in cerebral vasculature for the scan duration. Using time density curve (TDC) analysis, we explored if the steady-state assumption is met for C-arm CT PBV scans, and how consistent the contrast-material dynamics in cerebral vasculature are across patients.

METHODS

Thirty C-arm FDCT datasets of 26 patients with aneurysmal-SAH, acquired as part of a prospective study comparing C-arm CT PBV with MR-PWI, were analysed. TDCs were extracted from the 2D rotational projections. Goodness-of-fit of TDCs to a steady-state horizontal-line-model and the statistical similarity among the individual TDCs were tested. Influence of the differences in TDC characteristics on the agreement of resulting PBV measurements with MR-CBV was calculated.

RESULTS

Despite identical scan parameters and contrast-injection-protocol, the individual TDCs were statistically non-identical (p < 0.01). Using Dunn's multiple comparisons test, of the total 435 individual comparisons among the 30 TDCs, 330 comparisons (62%) reached statistical significance for difference. All TDCs deviated significantly (p < 0.01) from the steady-state horizontal-line-model. PBV values of those datasets for which the TDCs showed largest deviations from the steady-state model demonstrated poor agreement and correlation with MR-CBV, compared with the PBV values of those datasets for which the TDCs were closer to steady-state.

CONCLUSION

For clinical C-arm CT PBV examinations, the administered contrast material does not reach the assumed 'ideal steady-state' for the duration of scan. Using a prolonged injection protocol, the degree to which the TDCs approximate the ideal steady-state influences the agreement of resulting PBV measurements with MR-CBV.

Whole brain C-arm computed tomography parenchymal blood volume measurements

INTRODUCTION

C-arm flat detector computed tomography (FDCT) parenchymal blood volume (PBV) imaging in the neuro-interventional suite is a new technique for which detailed whole brain measurements have not been previously reported. This study aims to create a catalogue of PBV measurements for various anatomical regions encompassing the whole brain, using a three-dimensional volume-of-interest (3D-VOI) analysis.

METHODS

We acquired and analysed 30 C-arm FDCT datasets from 26 patients with aneurysmal subarachnoid haemorrhage (SAH), as part of a prospective study comparing C-arm computed tomography (CT) PBV with magnetic resonance perfusion-weighted imaging (MR-PWI). We calculated the PBV values for various brain regions with an automated analysis, using 58 pre-defined atlas-based 3D-VOIs encompassing the whole brain. VOIs partially or completely overlapping regions of magnetic resonance diffusion weighted imaging (MR-DWI) abnormality or magnetic resonance cerebral blood flow (MR-CBF) asymmetry were excluded from the analysis.

RESULTS

Of the 30 C-arm CT PBV datasets, 14 (54%; 12 patients) had areas of restricted diffusion, the majority of which were focal. The PBV values for the cerebral cortex and cerebral white matter were 4.01 ± 0.47 (mean ± SD) and 3.01 ± 0.39 ml per 100 ml. Lobar PBV values were: frontal lobe 4.2 ± 0.8, temporal lobe 4.2 ± 0.9, parietal lobe 3.9 ± 0.7 and occipital lobe 4.3 ± 0.8 ml/100 ml. The basal ganglia and brainstem PBV values were 3.4 ± 0.7 and 4.6 ± 0.6 ml/100 ml, respectively.

CONCLUSIONS

Compared with the typical reference cerebral blood volume (CBV) values reported in the literature for Positron Emission Tomography (PET), the PBV values were relatively high for the white matter and relatively low for the cortical grey matter. The reported catalogue of PBV values for various brain regions would be useful to inform future studies and could be used in clinical practice, when interpreting PBV maps.

C-Arm Flat Detector CT Parenchymal Blood Volume Thresholds for Identification of Infarcted Parenchyma in the Neurointerventional Suite

BACKGROUND AND PURPOSE

C-arm flat detector CT parenchymal blood volume imaging allows functional assessment of the brain parenchyma in the neurointerventional suite. This study aimed to determine the optimal C-arm flat detector CT parenchymal blood volume thresholds for demarcating irreversibly infarcted brain parenchyma by using areas of restricted diffusion on MR imaging as a surrogate marker for infarction.

MATERIALS AND METHODS

Twenty-six patients with delayed cerebral ischemia following aneurysmal SAH underwent research C-arm CT parenchymal blood volume scans by using a biplane angiography system and contemporaneous MR imaging. Infarct and peri-infarct tissue VOIs and their homologous VOIs in the contralateral uninvolved hemisphere were delineated on the basis of the review of DWI, PWI, and ADC images. Voxel-based receiver operating characteristic curve analysis was performed to estimate the optimal absolute and normalized parenchymal blood volume values for demarcating the infarct voxels.

RESULTS

For 12 patients with areas of restricted diffusion (infarct volume, 6.38 ± 7.09 mL; peri-infarct tissue volume, 22.89 ± 21.76 mL) based on the voxel-based receiver operating characteristic curve analysis, optimal absolute and normalized parenchymal blood volume thresholds for infarction were 2.49 mL/100 g (area under curve, 0.76; sensitivity, 0.69; specificity, 0.71) and 0.67 (area under curve, 0.77; sensitivity, 0.69; specificity, 0.72), respectively (P value < .01). For the moderate-to-severely ischemic peri-infarct zone, mean parenchymal blood volume values of the involved hemisphere VOIs were lower compared with the uninvolved hemisphere VOIs (P value < .01). However, for the mild-to-moderately ischemic peri-infarct zone, there was no statistically significant difference between the mean parenchymal blood volume values of the involved and uninvolved hemisphere VOIs (P value > .05).

CONCLUSIONS

C-arm flat detector CT parenchymal blood volume maps in conjunction with optimal thresholds are sensitive and specific for the estimation of irreversibly infarcted parenchyma. Parenchymal blood volume maps allow reliable detection of moderate-to-severe ischemia; however, the potential for underestimation of mild-to-moderate ischemia exists.

Non-invasive assessment of vasospasm following aneurysmal SAH using C-arm FDCT parenchymal blood volume measurement in the neuro-interventional suite: Technical feasibility

INTRODUCTION

Cerebral vasospasm is the leading cause of morbidity and mortality in patients with aneurysmal subarachnoid haemorrhage (SAH) surviving the initial ictus. Commonly used techniques for vasospasm assessment are digital subtraction angiography and transcranial Doppler sonography. These techniques can reliably identify only the major vessel spasm and fail to estimate its haemodynamic significance. To overcome these issues and to enable comprehensive non-invasive assessment of vasospasm inside the interventional suite, a novel protocol involving measurement of parenchymal blood volume (PBV) using C-arm flat detector computed tomography (FDCT) was implemented.

MATERIALS AND METHODS

Patients from the neuro-intensive treatment unit (ITU) with suspected vasospasm following aneurysmal SAH were scanned with a biplane C-arm angiography system using an intravenous contrast injection protocol. The PBV maps were generated using prototype software. Contemporaneous clinically indicated MR scan including the diffusion- and perfusion-weighted sequences was performed. C-arm PBV maps were compared against the MR perfusion maps.

RESULTS

Distribution of haemodynamic impairment on C-arm PBV maps closely matched the pattern of abnormality on MR perfusion maps. On visual comparison between the two techniques, the extent of abnormality indicated PBV to be both cerebral blood flow and cerebral blood volume weighted.

CONCLUSION

C-arm FDCT PBV measurements allow an objective assessment of the severity and localisation of cerebral hypoperfusion resulting from vasospasm. The technique has proved feasible and useful in very sick patients after aneurysmal SAH. The promise shown in this early study indicates that it deserves further evaluation both for post-SAH vasospasm and in other relevant clinical settings.

Volume changes of extremely large and giant intracranial aneurysms after treatment with flow diverter stents

INTRODUCTION

This study assessed volume changes of unruptured large and giant aneurysms (greatest diameter >20 mm) after treatment with flow diverter (FD) stents.

METHODS

Clinical audit of the cases treated in a single institution, over a 5-year period. Demographic and clinical data were retrospectively collected from the hospital records. Aneurysm volumes were measured by manual outlining at sequential slices using computerised tomography (CT) or magnetic resonance (MR) angiography data.

RESULTS

The audit included eight patients (seven females) with eight aneurysms. Four aneurysms involved the cavernous segment of the internal carotid artery (ICA), three the supraclinoid ICA and one the basilar artery. Seven patients presented with signs and symptoms of mass effect and one with seizures. All but one aneurysm was treated with a single FD stent; six aneurysms were also coiled (either before or simultaneously with FD placement). Minimum follow-up time was 6 months (mean 20 months). At follow-up, three aneurysms decreased in size, three were unchanged and two increased. Both aneurysms that increased in size showed persistent endosaccular flow at follow-up MR; in one case, failure was attributed to suboptimal position of the stent; in the other case, it was attributed to persistence of a side branch originating from the aneurysm (similar to the endoleak phenomenon of aortic aneurysms). At follow-up, five aneurysms were completely occluded; none of these increased in volume.

CONCLUSION

Complete occlusion of the aneurysms leads, in most cases, to its shrinkage. In cases of late aneurysm growth or regrowth, consideration should be given to possible endoleak as the cause.

In vitro and in vivo imaging characteristics assessment of polymeric coils compared with standard platinum coils for the treatment of intracranial aneurysms

BACKGROUND AND PURPOSE

Conventional platinum coils cause imaging artifacts that reduce imaging quality and therefore impair imaging interpretation on intraprocedural or noninvasive follow-up imaging. The purpose of this study was to evaluate imaging characteristics and artifact production of polymeric coils compared with standard platinum coils in vitro and in vivo.

MATERIALS AND METHODS

Polymeric coils and standard platinum coils were evaluated in vitro with the use of 2 identical silicon aneurysm models coiled with a packing attenuation of 20% each. DSA, flat panel CT, CT, and MR imaging were performed. In vivo evaluation of imaging characteristics of polymeric coils was performed in experimentally created rabbit carotid bifurcation aneurysms. DSA, CT/CTA, and MR imaging were performed after endovascular treatment of the aneurysms. Images were evaluated regarding visibility of individual coils, coil mass, artifact production, and visibility of residual flow within the aneurysm.

RESULTS

Overall, in vitro and in vivo imaging showed relevantly reduced artifact production of polymeric coils in all imaging modalities compared with standard platinum coils. Image quality of CT and MR imaging was improved with the use of polymeric coils, which permitted enhanced depiction of individual coil loops and residual aneurysm lumen as well as the peri-aneurysmal area. Remarkably, CT images demonstrated considerably improved image quality with only minor artifacts compared with standard coils. On DSA, polymeric coils showed transparency and allowed visualization of superimposed vessel structures.

CONCLUSIONS

This initial experimental study showed improved imaging quality with the use of polymeric coils compared with standard platinum coils in all imaging modalities. This might be advantageous for improved intraprocedural imaging for the detection of complications and posttreatment noninvasive follow-up imaging.

Does hypopituitarism recover when macroprolactinomas are treated with cabergoline?

OBJECTIVE

The frequency and the degree of recovery of anterior pituitary hormone deficits in patients with macroprolactinoma responsive to cabergoline are not clear. Our aim was to evaluate pituitary function in these patients with particular reference to an assessment of the possible restoration of pituitary deficits.

SUBJECTS AND METHODS

The records of all subjects prospectively presenting to our Department with macroprolactinomas treated with cabergoline over a 2-year period were reviewed. Pituitary function was assessed at diagnosis and, if abnormal, for three consecutive years for the GH, FSH/LH and ACTH axes, and at 3 years for the TSH axis.

RESULTS

Twelve patients were included. Severe GH deficiency was found in 83% at diagnosis and did not resolve in any patient at last assessment. Gonadotrophin deficiency was found in 90% at diagnosis and in 50% at last evaluation (showing reversal in 44% of deficient patients, all achieved within 1 year). ACTH deficiency was found in 17% at diagnosis and it did not reverse in any patient at last assessment. TSH deficiency was found in 36% at diagnosis and in 27% at last assessment (reversal in 25% of deficient patients).

CONCLUSIONS

In our study, in a group of patients with macroprolactinoma systematically assessed at intervals, pituitary dysfunction in response to cabergoline was found to be mostly irreversible, except for the gonadotroph axis which showed restoration in a subset of subjects following achievement of normoprolactinaemia. It would appear that the reversibility of pituitary axes may be less common than previously thought.

Tentorial dural fistulas: endovascular management and description of the medial dural-tentorial branch of the superior cerebellar artery

BACKGROUND AND PURPOSE

TDAVFs are uncommon causes of spontaneous intracranial hemorrhage. A retrospective review of their management was performed after repeatedly observing a previously under-recognized medial dural-tentorial branch of the SCA.

MATERIALS AND METHODS

Thirteen patients were diagnosed with TDAVFs by CT/MR imaging and DSA during a 5.8-year period. Seven patients presented after intracranial hemorrhage. Twelve patients were treated endovascularly, and one, surgically.

RESULTS

Eleven TDAVFs were located in the midline (7 at the falx cerebelli and 4 at the torcular), and 2 were petrotentorial. All torcular TDAVFs were associated with sinus thrombosis and showed bidirectional drainage relative to the tentorium. No sinus thrombosis was seen in the falx cerebelli subtype, which drained infratentorially only, except in 1 patient who had had unrelated surgery previously. Venous drainage was directly to cortical veins except for 1 petrotentorial and 2 torcular TDAVFs. A branch of the SCA, the medial dural-tentorial artery, was observed in 5 midline TDAVFs. Its anatomy was defined with selective angiography. Endovascular therapy resulted in a cure in 5 and subtotal occlusion in 6, and staged treatment is ongoing in 1 patient. One patient was cured after surgery.

CONCLUSIONS

TDAVFs frequently cause intracranial hemorrhage and therefore warrant treatment. Endovascular therapy proved effective in this series, and arteriography was essential for understanding the various fistula subtypes and for treatment planning. We emphasize the importance of recognizing the medial dural-tentorial artery of the SCA with its characteristic course along the tentorium on angiography. This artery should be included in future anatomic descriptions of the cranial blood supply.

Experimental evaluation of immediate recanalization effect and recanalization efficacy of a new thrombus retriever for acute stroke treatment in vivo

BACKGROUND AND PURPOSE

Currently, several new stent retriever devices for acute stroke treatment are under development and early clinical evaluation. Preclinical testing under standardized conditions is an important first step to evaluate the technical performance and potential of these devices. The aim of this study was to evaluate the immediate recanalization effect, recanalization efficacy, thrombus-device interaction, and safety of a new stent retriever intended for thrombectomy in patients with acute stroke.

MATERIAL AND METHODS

The pREset thrombectomy device (4 × 20 mm) was evaluated in 16 vessel occlusions in an established swine model. Radiopaque thrombi (10-mm length) were used for visualization of thrombus-device interaction during application and retrieval. Flow-restoration effect immediately after deployment and after 5-minute embedding time before retrieval, recanalization rate after retrieval, thromboembolic events, and complications were assessed. High-resolution FPCT was performed to illustrate thrombus-device interaction during the embedding time.

RESULTS

Immediate flow restoration was achieved in 75% of occlusions. An increase or stable percentage of recanalizations during embedding time before retrieval was seen in 56.3%; a decrease, in 12.5%; reocclusion of a previously recanalized vessel, in 18.8%; and no recanalization effect at all, in 12.5%. Complete recanalization (TICI 3) after retrieval was achieved in 93.8%; partial recanalization (TICI 2b), in 6.2%. No distal thromboembolic events were observed. High-resolution FPCT illustrated entrapment of the thrombus between the stent struts and compression against the contralateral vessel wall, leading to partial flow restoration. During retrieval, the thrombus was retained in a straight position within the stent struts.

CONCLUSIONS

In this experimental study, the pREset thrombus retriever showed a high recanalization rate in vivo. High-resolution FPCT allows detailed illustration of the thrombus-device interaction during embedding time and is advocated as an add-on tool to the animal model used in this study.

Technical feasibility and application of mechanical thrombectomy with the Solitaire FR Revascularization Device in acute basilar artery occlusion

BACKGROUND AND PURPOSE

Acute BAO is a devastating neurological condition associated with a poor clinical outcome and a high mortality rate. Recanalization has been identified as a major prognostic factor for good outcome in BAO. Mechanical thrombectomy using retrievable stents is an emerging treatment option for acute stroke. First clinical trials using stent retrievers have shown promising high recanalization rates. However, these studies mainly included large artery occlusions in the anterior circulation with only a few or single cases of BAO. Therefore, the purpose of this study was to evaluate technical feasibility, safety, and efficacy of mechanical thrombectomy using retrievable stent in the treatment of acute BAO.

MATERIALS AND METHODS

Fourteen consecutive patients with BAO undergoing endovascular therapy using retrievable stents (Solitaire FR Revascularization Device) were included. Additional multimodal treatment approaches included thromboaspiration, intravenous and/or intra-arterial thrombolysis, and PTA/ permanent stent placement. Recanalization rates after multimodal therapy and stent retrieval were determined. Clinical outcome and mortality were assessed 3 months after treatment.

RESULTS

Median patient age was 64.5 years (range 55-85). Median NIHSS score at presentation was 21 (range 5-36). Overall, successful recanalization (TICI 3 or 2b) was achieved in all patients (TICI 3 in 78.6%, 11/14). In 4 patients (28.6%), insufficient recanalization after stent retrieval was due to an underlying atherosclerotic stenosis. Additional deployment of a permanent intracranial stent was performed in 3 patients (21.4%) and PTA alone in 1 patient (7.1%), resulting in final TICI 3 in 1 patient and TICI 2b in 3 patients. Stent retrieval alone was performed in 4 patients (28.6%). Average number of device passes was 1.3 (range 1-3). Median procedure time to maximal recanalization was 47 minutes (range 10-252). No device-related complications or thromboembolic occlusion of a previously unaffected artery occurred. There was no symptomatic intracranial hemorrhage. At 3 months, good functional outcome (mRS 0-2) was observed in 28.6% (4/14); overall mortality was 35.7% (5/14).

CONCLUSIONS

A multimodal endovascular approach using retrievable stents in BAO has high recanalization rates, with very low complication rates. Underlying atherothrombotic stenotic lesions of the basilar artery may still necessitate additional permanent stent placement to achieve complete recanalization.

Recurrence of hyperprolactinaemia following discontinuation of dopamine agonist therapy in patients with prolactinoma occurs commonly especially in macroprolactinoma

CONTEXT

The optimal duration of dopamine agonist (DA) therapy in prolactinoma is unknown. There are concerns that despite low recurrence rates in highly selected groups, high recurrence rates after DA withdrawal may occur in routine practice.

OBJECTIVE

To explore recurrence of hyperprolactinaemia and predictive factors following DA withdrawal in patients with microprolactinoma and macroprolactinoma.

DESIGN

A retrospective study on adult patients with confirmed prolactinoma attending the Oxford Endocrine Department.

PATIENTS AND MEASUREMENTS

We identified patients with macroprolactinoma (n = 15) and microprolactinoma (n = 45) treated with DA therapy for >3 years, with a trial off DA therapy. None had other treatments. Measurements included recurrence of hyperprolactinaemia following DA withdrawal, tumour size (macroprolactinomas), duration of DA therapy, prolactin levels (baseline, during DA therapy, recurrence) and time to recurrence. Data were reported as mean (range).

RESULTS

During DA therapy, prolactin levels suppressed to normal range in all patients with macroprolactinoma and microprolactinoma, and most macroprolactinomas (n = 14) had substantial tumour shrinkage. Hyperprolactinaemia recurred in 93% of macroprolactinomas (n = 14) at 8·8 months (3-36) and 64% of microprolactinomas (n = 29) at 4·8 months (3-12). Duration of DA therapy was 7·5 years (4-15) for macroprolactinomas and 4·1 years (3-10) for microprolactinomas. Prolactin levels during DA therapy were 144 mU/l (7-336) for macroprolactinomas and 278 mU/l (30-629) for microprolactinomas. For microprolactinomas, prolactin levels during DA therapy were less suppressed in those with recurrence than in those without recurrence (P < 0·05).

CONCLUSIONS

In routine practice, hyperprolactinaemia recurs early in most macroprolactinomas (93%) and microprolactinomas (64%) following DA therapy discontinuation. For most macroprolactinomas, cessation of DA cannot be recommended even after 7 years of therapy.

Can we ever stop imaging in surgically treated and radiotherapy-naive patients with non-functioning pituitary adenoma?

BACKGROUND

Non-functioning pituitary adenomas (NFAs) are slow-growing tumours with reported re-growth rates following surgical resection alone of up to 50% at 10 years. Currently, the desired length of follow-up surveillance imaging in un-irradiated patients is unclear.

AIM

To clarify the timing of re-growth in patients with NFAs, treated solely by surgery without post-operative pituitary radiotherapy, and also to clarify whether continued imaging is necessary in these patients.

METHODS

A case note analysis of all patients who underwent surgery alone for NFA between January 1984 and December 2007 was undertaken. Patients were followed for a minimum of 1 year. Re-growth was diagnosed on the basis of radiological appearances with or without associated manifestations.

RESULTS

One hundred and fifty-five patients (94 males, mean age at diagnosis 57.9 (range 18.3-88) years) were included. Twenty-nine were followed up for more than 10 years. The mean follow-up following surgery was 6.1 years (median 4.3 (range 1-25.8)). Re-growth was documented in 54 (34.8%) cases and 20.4% of these cases showed relapse/re-growth 10 or more years after the initial surgery. Kaplan-Meier analysis showed relapse rates of 23.1, 46.7 and 67.9% at 5, 10 and 15 years respectively. There was a significant increase in the re-growth rates if there was either pituitary tumour remnant observed on the first post-operative scan (P≤0.001) or a younger age at initial surgery (P=0.034).

CONCLUSION

These results suggest that patients with NFAs need to be closely monitored following surgery, particularly those with post-operative tumour remnants. With 20% of relapse occurring after 10 years, follow-up surveillance needs to be continued beyond this time.

Pituitary apoplexy in non-functioning pituitary adenomas: long term follow up is important because of significant numbers of tumour recurrences

OBJECTIVES

The frequency of pituitary tumour regrowth after an episode of classical pituitary apoplexy is unknown. It is thus unclear whether regrowth, if it occurs, does so less frequently than with non-apoplectic non-functioning pituitary macroadenomas that have undergone surgery without postoperative irradiation. This has important repercussions on follow up protocols for these patients.

DESIGN

Retrospective cohort study of patients diagnosed with classical pituitary apoplexy in Oxford in the last 24 years.

MEASUREMENTS

MRI/CT scans of the pituitary were performed post-operatively and in those patients who did not receive pituitary irradiation, this was repeated yearly for 5 years and 2 yearly thereafter.

RESULTS

Thirty-two patients with non-functioning pituitary adenomas who presented with classical pituitary apoplexy were studied. There were 23 men and the mean age was 56·6 years (range 29-85). The mean follow up period was 81 months (range 6-248). Five patients received adjuvant radiotherapy within 6 months of surgery and were excluded from further analysis. In this group, there were no recurrences during a mean follow up of 83 months (range 20-150). In the remaining 27 cases there were 3 recurrences, with a mean of 79 months follow up (range 6-248) occurring 12, 51 and 86 months after surgery. This gives a recurrence rate of 11·1% at a mean follow up of 6·6 years post surgery. All recurrences had residual tumour on the post operative scan.

CONCLUSIONS

Patients with classical pituitary apoplexy may show recurrent pituitary tumour growth and therefore these patients need continued post-operative surveillance if they have not had post-operative radiotherapy.

Outcome in surgically treated Rathke's cleft cysts: long-term monitoring needed

OBJECTIVE

To clarify the outcome of all cases of Rathke's cleft cysts (RCC) treated surgically and followed up in Oxford during a long-term period.

SUBJECTS AND METHODS

The records of all patients with RCC seen in the Department of Endocrinology between January 1978 and June 2009 were reviewed.

RESULTS

A total of 33 patients (20 females, median age 43 years) were identified. At presentation, major visual field defects were detected in 58% of patients and gonadotrophin, ACTH and TSH deficiency in 60, 36 and 36% of patients respectively. Desmopressin treatment was required in 18% of patients. Treatment consisted of cyst evacuation combined with or without biopsy/removal of the wall. Post-operatively, visual fields improved in 83% of patients with impairment, whereas there was no reversal of ACTH or TSH deficiency or of diabetes insipidus. All but one subject had imaging follow-up during a mean period of 48 months (range 2-267). Cyst relapse was detected in 22% of patients at a mean interval of 29 months (range 3-48 months); in 57% of them, the recurrence was symptomatic. Relapse-free rates were 88% at 24-months and 52% at 48-months follow-up. At last assessment, at least quadrantanopia was reported in 19% of patients, gonadotrophin, ACTH and TSH deficiency in 50, 42 and 47% of patients respectively. Desmopressin treatment was required in 39% of patients.

CONCLUSIONS

In this study of patients with RCC and long-term follow-up, we showed a considerable relapse rate necessitating long-term monitoring. Surgical intervention is of major importance for the restoration of visual field defects, but it does not improve endocrine morbidity, which in the long-term affects a substantial number of patients.

Sixteen-year single-surgeon experience with coil embolization for ruptured intracranial aneurysms: recurrence rates and incidence of late rebleeding

Object

Over a 16-year period, 570 patients presenting with acute aneurysmal subarachnoid hemorrhage were successfully treated using endosaccular coil embolization within 30 days of hemorrhage by a single surgeon. Patients were followed to assess the stability of aneurysm occlusion and its longer-term efficacy in protecting against rebleeding.

Methods

Patients were followed for 6 to 191 months (mean 73.7 months, median 67 months) by clinical review, angiography performed at 6 and 24 months posttreatment, and questionnaires sent via the postal service every 5 years. Late rebleeding was defined as > 30 days after treatment.

Results

Stable angiographic occlusion was evident in 74.5% of small, 72.2% of large, and 60% of giant aneurysms. Recurrent filling was found in 119 (26.3%) of 452 aneurysms. Rebleeding was diagnosed in 9 patients (6 treated aneurysms) and occurred between 2 and 114 months posttreatment. It was due to aneurysm recurrence in 6 patients, rupture of a coincidental untreated aneurysm in 2 patients, and rupture of a de novo aneurysm in 1 patient. Rebleeding occurred in 3 (2.5%) of 119 unstable aneurysms and in 3 (0.9%) of 333 stable aneurysms, as seen on initial follow-up angiography studies. Annual rebleeding rates ranged from 0.2% to 0.6% for all causes and from 0.2% to 0.4% for rebleeding of treated aneurysms. No rebleeding was recorded after the first decade, with 138 patients having more than 10 years of follow-up.

Conclusions

Periodic follow-up with angiographic studies after coil embolization is recommended to identify aneurysm recurrence and patients at a high risk of late rebleeding in the medium term. More frequent follow-up is recommended for patients harboring coincidental unruptured aneurysms.

Endovascular stroke treatment today

The purpose of this study was to review current treatment options in acute ischemic stroke, focusing on the latest advances in the field of mechanical recanalization. These devices recently made available for endovascular intracranial thrombectomy show great potential in acute stroke treatments. Compelling evidence of their recanalization efficacy comes from current mechanical embolectomy trials. In addition to allowing an extension of the therapeutic time window, mechanical recanalization devices can be used without adjuvant thrombolytic therapy, thus diminishing the intracranial bleeding risk. Therefore, these devices are particularly suitable in patients in whom thrombolytic therapy is contraindicated. IV and IA thrombolysis and bridging therapy are viable options in acute stroke treatment. Mechanical recanalization devices can potentially have a clinically relevant impact in the interventional treatment of stroke, but at the present time, a randomized study would be beneficial.

Nelson's syndrome

Nelson's syndrome is a potentially life-threatening condition that does not infrequently develop following total bilateral adrenalectomy (TBA) for the treatment of Cushing's disease. In this review article, we discuss some controversial aspects of Nelson's syndrome including diagnosis, predictive factors, aetiology, pathology and management based on data from the existing literature and the experience of our own tertiary centre. Definitive diagnostic criteria for Nelson's syndrome are lacking. We argue in favour of a new set of criteria. We propose that Nelson's syndrome should be diagnosed in any patient with prior TBA for the treatment of Cushing's disease and with at least one of the following criteria: i) an expanding pituitary mass lesion compared with pre-TBA images; ii) an elevated 0800 h plasma level of ACTH (>500 ng/l) in addition to progressive elevations of ACTH (a rise of >30%) on at least three consecutive occasions. Regarding predictive factors for the development of Nelson's syndrome post TBA, current evidence favours the presence of residual pituitary tumour on magnetic resonance imaging (MRI) post transsphenoidal surgery (TSS); an aggressive subtype of corticotrophinoma (based on MRI growth rapidity and histology of TSS samples); lack of prophylactic neoadjuvant pituitary radiotherapy at the time of TBA and a rapid rise of ACTH levels in year 1 post TBA. Finally, more studies are needed to assess the efficacy of therapeutic strategies in Nelson's syndrome, including the alkylating agent, temozolomide, which holds promise as a novel and effective therapeutic agent in the treatment of associated aggressive corticotroph tumours. It is timely to review these controversies and to suggest guidelines for future audit.

Early experience in the treatment of intra-cranial aneurysms by endovascular flow diversion: a multicentre prospective study

INTRODUCTION

Flow diversion is a new approach to the endovascular treatment of intracranial aneurysms which uses a high density mesh stent to induce sac thrombosis. These devices have been designed for the treatment of complex shaped and large size aneurysms. So far published safety and efficacy data on this approach is sparse.

MATERIAL AND METHODS

Over 8 months, standardized clinical and angiographic data were collected on 70 patients treated with a flow diverter device (SILK flow diverter (SFD)) in 18 centres worldwide. Treatment and early follow up details were audited centrally. SFDs were deployed alone in 57 (81%) or with endosaccular coils in 10 (14%) aneurysms, which included: 44 (63%) saccular, 26 (37%) fusiform shapes and 18 (26%) small, 37 (53%) large, 15 (21%) giant sizes. Treatment outcome data up to 30 days were reported for all patients, with clinical (50 patients) and imaging (49 patients) follow up (median 119 days) data available.

RESULTS

Difficulties in SFD deployment were reported in 15 (21%) and parent artery thrombosis in 8 (11%) procedures. Procedural complications caused stroke in 1 and serious extracranial bleeding in 3 patients; 2 of whom developed fatal pneumonias. Delayed worsening of symptoms occurred in 5 patients (3 transient, 1 permanent neurological deficit, and 1 death) and fatal aneurysm bleeding in 1 patient. Overall permanent morbidity rates were 2 (4%) and mortality 4 (8%). Statistical analysis revealed no significant association between complications and variables related to treated aneurysm morphology or rupture status.

CONCLUSION

This series is the largest reporting outcome of the new treatment approach and provides data for future study design. Procedural difficulties in SFD deployment were frequent and anti-thrombosis prophylaxis appears to reduce the resulting clinical sequelae, but at the cost of morbidity due to extracranial bleeding. Delayed morbidity appears to be a consequence of the new approach and warrants care in selecting patients for treatment and future larger studies.

Influence of Coil Geometry on Intra-Aneurysmal Packing Density: Evaluation of a New Primary Wind Technology

Introduction: This prospective randomized double-blinded in-vitro study was conducted to determine the relative Packing Density (PD) of the new Deltapaq coil (Micrus Endovascular) as compared to Micrus’s conventional filling CHE (Helipaq) and finishing CFS (Ultipaq) coils. Methods: Two physicians independently deployed the coils under fluoroscopy into a 4mm berry shaped glass aneurysm. Each coil tested was a 4mm × 35cm coil specially made for this study. Physicians and observer were blinded as to the type of coil. Five samples per group, per operator, were deployed. Results: mean PD were 36.6% (Helipaq), 37.9% (Ultipaq) and 40.4% (Deltapaq). Two-sample T-test showed a significantly higher PD of Deltapaq versus Helipaq (p < 0.022). Discussion: Higher coil PD and better neck coverage may provide an increased biomechanical stability and may potentially reduce the recanalization rate of aneurysms. Conclusion: The new Deltapaq coil may have the potential to achieve higher packing densities in the treatment of aneurysms.

Endovascular treatment of very small intracranial aneurysms

Object

Endovascular treatment of very small aneurysms poses a significant technical challenge for endovascular therapists. The authors review their experience with a series of patients who had intracranial aneurysms smaller than 3 mm in diameter.

Methods

Between 1995 and 2006, 97 very small aneurysms (defined for purposes of this study as < 3 mm in diameter) were diagnosed in 94 patients who were subsequently referred for endovascular treatment. All patients presented after subarachnoid hemorrhage, which was attributed to the very small aneurysms in 85 patients. The authors reviewed the endovascular treatment, the clinical and angiographic results of the embolization, and the complications.

Results

Five (5.2%) of the 97 endovascular procedures failed, and these patients underwent craniotomy and clip ligation. Of the 92 aneurysms successfully treated by coil embolization, 64 (69.6%) were completely occluded and 28 (30.4%) showed minor residual filling or neck remnants on the immediate postembolization angiogram. Complications occurred in 7 (7.2%) of 97 procedures during the treatment (3 thromboembolic events [3.1%] and 4 intraprocedural ruptures [4.1%]). Seventy-six patients were followed up angiographically; 4 (5.3%) of these 76 showed angiographic evidence of recanalization that required retreatment. The clinical outcomes for the 76 patients were also graded using the Glasgow Outcome Scale. In 61 (80.3%) cases the outcomes were graded 4 or 5, whereas in 15 (19.7%) they were graded 3. Seven patients (7.4%) died (GOS Grade 1), 2 due to procedure-related complications (intraoperative rupture) and 5 due to complications related to the presenting subarachnoid hemorrhage.

Conclusions

Endosaccular coil embolization of very small aneurysms is associated with relatively high rates of intraprocedural rupture, especially intraoperative rupture. With the advent of more sophisticated endovascular materials (microcatheters and microguidewires, soft and ultrasoft coils, and stents) endovascular procedures have become feasible and can lead to a good angiographic outcome.

Rest versus exercise hemodynamics for middle cerebral artery aneurysms: a computational study

BACKGROUND AND PURPOSE

Exercise is an accepted method of improving cardiovascular health; however, the impact of increases in blood flow and heart rate on a cerebral aneurysms is unknown. This study was performed to simulate the changes in hemodynamic conditions within an intracranial aneurysm when a patient exercises.

MATERIALS AND METHODS

Rotational 3D digital subtraction angiograms were used to reconstruct patient-specific geometries of 3 aneurysms located at the bifurcation of the middle cerebral artery. CFD was used to solve for transient flow fields during simulated rest and exercise conditions. Inlet conditions were set by using published transcranial Doppler sonography data for the middle cerebral artery. Velocity fields were analyzed and postprocessed to provide physiologically relevant metrics.

RESULTS

Overall flow patterns were not significantly altered during exercise. Across subjects, during the exercise simulation, time-averaged WSS increased by a mean of 20% (range, 4%-34%), the RRT of a particle in the near-wall flow decreased by a mean of 28% (range, 13%-40%), and time-averaged pressure on the aneurysm wall did not change significantly. In 2 of the aneurysms, there was a 3-fold order-of-magnitude spatial difference in RRT between the aneurysm and surrounding vasculature.

CONCLUSIONS

WSS did not increase significantly during simulated moderate aerobic exercise. While the reduction in RRT during exercise was small in comparison with spatial differences, there may be potential benefits associated with decreased RRT (ie, improved replenishment of nutrients to cells within the aneurysmal tissue).

Substantial Observer Variability in the Differentiation Between Primary Intracerebral Hemorrhage and Hemorrhagic Transformation of Infarction on CT Brain Imaging

Background and Purpose— CT remains the most commonly used imaging technique in acute stroke but is often delayed after minor stroke. Interobserver reliability in distinguishing hemorrhagic transformation of infarction from intracerebral hemorrhage may depend on delays to CT but has not been reported previously despite the clinical importance of this distinction.

Methods— Initial CT scans with intraparenchymal hematoma from the first 1000 patients with stroke in the Oxford Vascular Study were independently categorized as intracerebral hemorrhage or hemorrhagic transformation of infarction by 5 neuroradiologists, both blinded and unblinded to clinical history. Thirty scans were reviewed twice. Agreement was quantified by the κ statistic.

Results— Seventy-eight scans showed intraparenchymal hematoma. Blinded pairwise interrater agreements for a diagnosis of intracerebral hemorrhage ranged from κ=0.15 to 0.48 with poor overall agreement (κ=0.35; 95% CI, 0.15 to 0.54) even after unblinding (κ=0.41; 0.21 to 0.60). Blinded intrarater agreements ranged from κ=0.21 to 0.92. Lack of consensus after unblinding was greatest in patients scanned ≥24 hours after stroke onset (67% versus 25%, P =0.001) and in minor stroke (National Institutes of Health Stroke Scale ≤5: 56% versus 29%, P =0.04) with disagreement in 75% of patients scanned ≥24 hours after minor stroke and in 48% of all 30-day stroke survivors in whom reliable diagnosis would be expected to influence long-term management.

Conclusion— Reliability of diagnosis of intraparenchymal hematoma on CT brain scan in minor stroke is poor, particularly if scanning is delayed. Immediate brain imaging is justified in patients with minor stroke.

Percutaneous transluminal angioplasty and stent placement in acute vessel occlusion: evaluation of new methods for interventional stroke treatment

BACKGROUND AND PURPOSE

The major goal of acute ischemic stroke treatment is fast and sufficient recanalization. Percutaneous transluminal balloon angioplasty (PTA) and/or placement of a stent might achieve both by compressing the thrombus at the occlusion site. This study assesses the feasibility, recanalization rate, and complications of the 2 techniques in an animal model.

MATERIALS AND METHODS

Thirty cranial vessels of 7 swine were occluded by injection of radiopaque thrombi. Fifteen vessel occlusions were treated by PTA alone and 15, by placement of a stent and postdilation. Recanalization was documented immediately after treatment and after 1, 2, and 3 hours. Thromboembolic events and dissections were documented.

RESULTS

PTA was significantly faster to perform (mean, 16.6 minutes versus 33.0 minutes for stent placement; P < .001), but the mean recanalization rate after 1 hour was significantly better after stent placement compared with PTA alone (67.5% versus 14.6%, P < .001). Due to the self-expanding force of the stent, vessel diameter further increased with time, whereas the recanalization result after PTA was prone to reocclusion. Besides thromboembolic events related to the passing maneuvers at the occlusion site, no thrombus fragmentation and embolization occurred during balloon inflation or stent deployment. Flow to side branches could also be restored at the occlusion site because it was possible to direct thrombus compression.

CONCLUSIONS

Stent placement and postdilation proved to be much more efficient in terms of acute and short-term vessel recanalization compared with PTA alone.

Territorial and microvascular perfusion impairment in brain arteriovenous malformations

BACKGROUND AND PURPOSE

Both the existence and clinical relevance of a steal phenomenon in brain arteriovenous malformations (AVMs) remains a matter of debate. This study aimed to assess perfusion in the brain adjacent to brain AVMs and to relate these to macrovascular blood flow in a single measurement.

MATERIALS AND METHODS

Twenty consecutive patients with AVMs with a median age of 37 years were evaluated by 3T MR imaging by using 3D time-resolved MR angiography to determine blood flow and perfusion patterns. Cerebral perfusion was estimated by using an arterial spin-labeling technique in vascular territories around the nidus and in symmetric regions of interest in the ipsilateral and contralateral hemispheres. Mapping of concentric shells around the nidus was used to define the immediate and adjacent brain and relative perfusion reductions >20% of baseline, termed perinidal dip (PND).

RESULTS

A significant reduction in perfusion ratios between ipsilateral and contralateral hemispheres remote to the AVMs was demonstrated in the middle and posterior cerebral artery territories. PND was detected in 5 patients, and 17 patients overall showed reduced perfusion in the perinidal region on visual inspection. There was a negative correlation of the hemispheric territorial perfusion with the affected/nonaffected inflow time ratio (R = -0.402, P = .015).

CONCLUSIONS

The perfusion impairment in vascular territories adjacent to brain AVMs that we identified as PND may reflect the existence of 2 levels of perfusion impairment: a territorial and a microvascular perfusion disturbance. Although the hemispheric asymmetry in territorial perfusion seems the result of arterioarterial redistribution, the PND was inhomogeneously distributed within a single vascular territory and thus might result from low perfusion pressure in small arteries and arterioles.

Endovascular treatment of intracranial microarteriovenous malformations

Object

Microarteriovenous malformations (micro-AVMs) are an uncommon subgroup of brain AVMs defined by a nidus measuring < 1 cm in diameter. The clinical features, angiographic characteristics, and outcomes in patients with micro-AVMs who had been treated endovascularly after presenting with hemorrhage were reviewed to identify common features affecting prognosis.

Methods

Between 1997 and 2006, 25 patients (12 females and 13 males) with 26 micro-AVMs were treated. Twenty-four patients presented with intracerebral hematoma and 1 with subarachnoid hemorrhage only. All patients underwent CT on admission, diagnostic cerebral angiography, and 1 session of endovascular treatment during the acute phase.

Results

Procedure-related complications occurred in 3 patients (12%), which caused temporary hemiparesis in 1 (4%) and no clinical sequelae in 2 patients (8%). Complete nidus obliteration was achieved at the end of the embolization in 22 (84.6%) of 26 lesions. Two recurrences were evident on follow-up angiography 6 months postembolization, resulting in a complete obliteration rate of 77% (20 of 26 lesions) after a single treatment. Late angiography was performed in 12 patients, and no further recurrences were identified.

Conclusions

Immediate complete obliteration of a micro-AVM with a high permanent cure and low morbidity rates was accomplished using endovascular treatment. Early embolization after bleeding should be considered as an alternative to resection.

Abciximab for thrombolysis during intracranial aneurysm coiling

INTRODUCTION

Thrombotic events are a common and severe complication of endovascular aneurysm treatment with significant impact on patients' outcome. This study evaluates risk factors for thrombus formation and assesses the efficacy and safety of abciximab for clot dissolution.

MATERIALS AND METHODS

All patients treated with abciximab during (41 patients) or shortly after (22 patients) intracranial aneurysm coil embolisation were retrieved from the institutional database (2000 to 2007, 1,250 patients). Sixty-three patients (mean age, 55.3 years, +/- 12.8) had received either intra-arterial or intravenous abciximab. Risk factors for clot formation were assessed and the angiographic and clinical outcome evaluated.

RESULTS

No aneurysm rupture occurred during or after abciximab application. The intra-procedural rate of total recanalisation was 68.3%. Thromboembolic complications were frequently found in aneurysms of the Acom complex and of the basilar artery, whilst internal carotid artery aneurysms were underrepresented. Two patients died of treatment-related intracranial haemorrhages into preexisting cerebral infarcts. Two patients developed a symptomatic groin haematoma.

CONCLUSIONS

Abciximab is efficacious and safe for thrombolysis during and after endovascular intracranial aneurysm treatment in the absence of preexisting ischaemic stroke.

DELAYED VISUAL DEFICITS AND MONOCULAR BLINDNESS AFTER ENDOVASCULAR TREATMENT OF LARGE AND GIANT PARAOPHTHALMIC ANEURYSMS

OBJECTIVE

Paraophthalmic aneurysms may exert mass effect on the optic apparatus. Although surgical clipping and endovascular coiling of these aneurysms can be complicated by immediate postoperative visual deterioration, endovascular coil embolization has the unique risk of visual complications later (&gt;24 h) in the perioperative period.

METHODS

Six patients with a delayed onset of vision loss after technically successful coil embolization of paraophthalmic region aneurysms were identified. All available clinical, angiographic, and cross sectional imaging for these patients, in addition to histopathological data, were reviewed.

RESULTS

Six patients who underwent endovascular treatment of paraclinoid aneurysms at our institutions developed delayed postoperative visual decline. Four were treated with combination hydrogel-coated and bare platinum coils, one with hydrogel-coated coils, and one with bare platinum coils. Three patients presented with some degree of visual impairment caused by their aneurysms. Catheter angiography performed after the visual decline revealed no etiology in any of the cases. Magnetic resonance imaging was performed in all patients and was unremarkable in two. At follow-up, two had improved, three remained unchanged, and one patient died before any follow-up assessment of her vision.

CONCLUSION

Both acute and delayed visual disturbances can present after the endovascular treatment of carotid artery paraophthalmic aneurysms. Delayed visual deterioration can be observed up to 35 days after embolization. Although the cause is still undefined, it is likely that the more delayed visual deterioration can be attributed to progression of mass effect and/or perianeurysmal inflammatory change. Our case series raises the possibility that this phenomenon may be more likely with HydroCoil (HydroCoil Embolic System; MicroVention, Aliso Viejo, CA). This possibility should be taken into account by neurointerventionists when selecting a coil type to treat large paraophthalmic aneurysms.

The haemodynamics of endovascular aneurysm treatment: a computational modelling approach for estimating the influence of multiple coil deployment

This paper proposes a novel computational methodology for modelling the haemodynamic effects of endovascular coil embolization for cerebral aneurysms. We employ high-resolution 3-D angiographic data to reconstruct the intracranial geometry and we model the coiled part of the aneurysm as a porous medium, with porosity decreasing as coils are inserted. The actual dimensions of the coils employed are used to determine the characteristics of the porous medium. Simulation results for saccular aneurysms from the anterior communicating and middle cerebral arteries show that insertion of coils rapidly changes intraaneurysmal blood flow and causes reduction in mural pressure and blood velocity up to stagnation, providing favorable conditions for thrombus formation and obliteration of the aneurysm.

Surgical debulking of pituitary macroadenomas causing acromegaly improves control by lanreotide

BACKGROUND

Macroadenomas causing acromegaly are cured surgically in only around 50% of patients. Primary medical treatment with somatostatin analogues has been suggested to be a means of treating patients with a potentially poor surgical outcome. Previous retrospective studies have also suggested that surgical debulking of pituitary tumours causing acromegaly improves control by somatostatin analogues. No prospective study using lanreotide has been carried out thus far to assess whether this is the case.

OBJECTIVE

We carried out a prospective study to assess whether surgical debulking of pituitary macroadenomas causing acromegaly improved the subsequent control of acromegaly by the somatostatin analogue lanreotide.

PATIENTS AND METHODS

We treated 26 consecutive patients [10 males and 16 females--median age 53.5 years (range 22-70)] with macroadenoma causing acromegaly unselected for somatostatin response for 16 weeks with lanreotide, maximizing GH and IGF-I suppression, if necessary, by incremental dosing. Surgical resection was carried out and the patients were re-assessed off medical treatment at 16 weeks following surgery. Those with nadir GH > 2 mU/l in the oral glucose tolerance test (OGTT) and a mean GH in the GH day curve (GHDC) > 5 mU/l were subsequently restarted on lanreotide and the responses were assessed at the same time points as during the preoperative lanreotide treatment.

RESULTS

GH values fell on lanreotide treatment and prior to surgery they were considered 'safe' (mean GH in GHDC < 5 mU/l) in eight patients (30.7%). After surgery, they were 'safe' in 18 patients (69.2%). The figures for normal IGF-I were 11 (42.3%) before surgery and 23 (88.5%) after surgery. After surgery, six patients had nadir GH > 2 mU/l in the OGTT and 'unsafe' GH levels (mean GH in GHDC > 5 mU/l); on re-exposure to lanreotide, GH levels fell in all patients and at the end of 16 weeks postsurgery, they were 'safe' in three of them (50%) (P < 0.05). Pituitary tumour volume was also assessed prospectively, preoperatively on lanreotide and showed a mean fall of 33.1%. Eighty-three percent of patients had > 20% shrinkage.

CONCLUSIONS

In this first prospective study using lanreotide, surgical debulking of pituitary tumours causing acromegaly improved subsequent postoperative control by the somatostatin analogue lanreotide. Surgery should, therefore, be considered in patients with macroadenoma causing acromegaly, even if there is little prospect of surgical cure. Lanreotide causes significant pituitary tumour shrinkage in the majority of patients.

A case of macroprolactinoma encasing an internal carotid artery aneurysm, presenting as pituitary apoplexy

We present the first case of successful non-surgical treatment of an internal carotid aneurysm, embedded within a macroprolactinoma. A 53 year old male, with a previous history of Non-Hodgkin's Lymphoma (NHL), presented with severe right sided frontal headache, decreased visual acuity, and ophthalmolplegia due to a third nerve palsy. A CT scan showed a 4.6 by 4.8 cm mass in the pituitary fossa with bony erosion. Initially, it was thought to be a cerebral recurrence of the Non-Hodgkin's disease. Direct questioning revealed a long history of erectile dysfunction with loss of libido. Prolactin at presentation was 537, 200 mU/l and a diagnosis of macroprolactinoma, with apoplexy was made. A subsequent MRI brain confirmed a large macroadenoma with an intra cavernous aneurysm encased by the tumour. A therapeutic dilemma ensued due to the need for urgent decompression of the visual pathways, preferably by surgery. However, in the presence of an intrasellar aneurysm, surgery would have been extremely hazardous. The patient was therefore commenced on cabergoline and rapidly titrated up to 4 mg per week. The aneurysm was treated by endovascular occlusion of the right carotid artery under radiological control. The combination of these therapies, without conventional surgical intervention, resulted in resolution of the third nerve palsy and recovery of visual acuity in the left eye. The diagnosis and management of this condition was challenging and the final outcome, with non-surgical treatment and carotid artery occlusion was satisfactory.

What is the natural history of nonoperated nonfunctioning pituitary adenomas?

BACKGROUND

Series of patients systematically investigating the outcome of clinically nonfunctioning pituitary adenomas (NFAs) not treated by surgery or radiotherapy during long follow-up periods are limited. Most reports involve the follow-up of selected cases of incidentally found lesions, rendering their results unreliable on the assessment of the pros and cons of a 'watch and wait' policy.

OBJECTIVE

To investigate the outcome of a series of consecutive patients with presumed NFA (microadenoma or macroadenoma), who were not offered treatment at presentation (for a number of reasons) and were regularly followed up, and to identify possible factors predicting subsequent increase in tumour size.

PATIENTS AND METHODS

All patients presenting to the Department of Endocrinology in Oxford between 1989 and 2005 with presumed NFA were studied retrospectively. Inclusion criteria were: (i) imaging features suggestive of a pituitary adenoma, (ii) no clinical and/or biochemical evidence of hormonal hypersecretion by the tumour, (iii) monitoring being the initial choice of management, and (iv) at least one repeat scan during the follow-up period. Subjects presenting with acute apoplexy were excluded. Follow-up management included clinical evaluation, assessment of the visual acuity and fields and imaging at regular intervals. The duration of observation was estimated from the dates of first and last scan.

RESULTS

Forty subjects were included in the study [18 males/22 females, median age 52 years (range 18-89), 16 with microadenoma/24 with macroadenoma]. The mean follow-up period was 42 months (range 8-128). During the observation interval, 12.5% of the microadenomas and 50% of the macroadenomas increased in size. The 48-month probability for enlargement was 19% for the microadenomas and 44% for the macroadenomas. Among the subjects with tumour enlargement, 57% showed new or worse visual field defects (all had macroadenomas) and 21% showed chiasmatic involvement on imaging without visual deterioration (all had macroadenomas). New or worse visual field defects were found in 67% of the macroadenomas showing increase in size. No microadenoma enlarged to cause visual deterioration. In microadenomas, sex and age at presentation were not predictors of enlargement. In macroadenomas, sex, age, visual field defects or cavernous sinus invasion at presentation were not predictors of enlargement.

CONCLUSIONS

The 'watch and wait' policy seems reasonable for microadenomas but is probably not a safe approach for macroadenomas, which appear to have a significant growth potential; in these cases, given the lack of established medical treatment, the decision for surgical intervention should balance the presence of significant comorbidities and the anaesthetic/peri-operative risks at presentation against the probability of tumour enlargement and its consequences, as well as the possible loss of advantages associated with early operation.

Nonsurgical cerebrospinal fluid rhinorrhea in invasive macroprolactinoma: incidence, radiological, and clinicopathological features

CONTEXT

Macroprolactinomas (MPRLs) may result in nonsurgical (spontaneous or dopamine agonist induced) cerebrospinal fluid (CSF) rhinorrhea; however, the incidence of and mechanisms underlying this phenomenon are poorly understood.

OBJECTIVE

The objective of the study was to determine the incidence of nonsurgical rhinorrhea and identify biochemical, radiological, and histopathological factors associated with leakage.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective review of MPRL patients (n = 114) was compared with patients with nonfunctioning pituitary adenoma (NFA) (n = 181) seen over a 19-yr period (1985-2004).

MAIN OUTCOME MEASURES

Incidence of CSF rhinorrhea, factors predictive of leakage, and differential expression of candidate markers of invasiveness were measured.

RESULTS

Nonsurgical CSF rhinorrhea occurred in 8.7% of MPRLs (10 of 114) [2.6% spontaneous (three of 114), 6.1% dopamine agonist induced (seven of 114)], whereas no NFAs developed nonsurgical rhinorrhea. There was a clear male preponderance in MPRLs with nonsurgical rhinorrhea (males to females, 9:1, P = 0.008). Dopamine agonist resistance was more frequent in MPRLs with rhinorrhea than with MPRLs without rhinorrhea [30% (n = 10) vs. 5% (n = 104) P = 0.003]. Baseline prolactin levels, rate of prolactin decline in response to dopamine agonists, and tumor volume at diagnosis did not predict CSF leakage. Candidate markers of invasiveness, specifically the protease-activated receptor 1 and e-cadherin expression scores and tumor macrophage density, were not significantly different between groups; MPRL+CSF rhinorrhea (n = 6), MPRL without CSF rhinorrhea (n = 9), and NFAs (n = 9).

CONCLUSIONS

The incidence of nonsurgical CSF rhinorrhea in MPRL patients (8.7%) is higher than expected. Dopamine agonist resistance is more common in MPRLs with CSF rhinorrhea; however, whether this is a mechanistic relationship requires further study. Protease-activated receptor 1 expression, e-cadherin expression, and macrophage infiltration rates do not distinguish tumors with from those without CSF rhinorrhea.

Retreatment of ruptured cerebral aneurysms in patients randomized by coiling or clipping in the International Subarachnoid Aneurysm Trial (ISAT)

BACKGROUND AND PURPOSE

Because the long-term security of endovascular treatments remains uncertain, a follow-up study of the patients treated in the International Subarachnoid Aneurysm Trial was performed to compare the frequency, timing, and consequences of aneurysm recurrence.

METHODS

Patient data were reclassified by actual treatment performed. Aneurysm and patient characteristics, including occlusion grades, time and type of retreatment, and clinical outcomes, were compared. The relationship between these variables and late retreatment as a surrogate for recurrence was analyzed by means of the Cox proportional hazards model.

RESULTS

Retreatment was performed in 191 of 1096 (17.4%) patients after primary endovascular coiling (EVT) and in 39 of 1012 patients (3.8%) after neurosurgical clipping. After EVT, 97 (8.8%) patients were retreated early and 94 (9.0%) late, 7 (0.6%) after rebleeding and 87 (8.3%) without. The mean time to late retreatment was 20.7 months. After neurosurgical clipping, 30 (2.9%) patients were retreated early and 9 (0.85%) late, 3 (0.3%) after rebleeding and 6 (0.6%) without. The mean time to late retreatment was 5.7 months. The hazard ratio (HR) for retreatment after EVT was 6.9 (95% CI=3.4 to 14.1) after adjustment for age (P=0.001, HR=0.97, 95% CI=0.95 to 0.98), lumen size (P=0.006, HR=1.1, 95% CI=1.03 to 1.18), and incomplete occlusion (P<0.001, HR=7.6, 95% CI=3.3 to 17.5).

CONCLUSIONS

Late retreatment was 6.9 times more likely after EVT. Younger age, larger lumen size, and incomplete occlusion were risk factors for late retreatment after EVT. After neurosurgical clipping, retreatments were earlier; whereas EVT retreatments continued to be performed throughout the follow-up period. Short-term follow-up imaging is therefore insufficient to detect recurrences after EVT.