Radiological follow-up of endovascularly treated intracranial aneurysms: a survey of current practice in the UK and Ireland.

PURPOSE: Due to the risk of intracranial aneurysm (IA) recurrence and the potential requirement for re-treatment following endovascular treatment (EVT), radiological follow-up of these aneurysms is necessary. There is little evidence to guide the duration and frequency of this follow-up. The aim of this study was to establish the current practice in neurosurgical units in the UK and Ireland. METHODS: A survey was designed with input from interventional neuroradiologists and neurosurgeons. Neurovascular consultants in each of the 30 neurosurgical units providing a neurovascular service in the UK and Ireland were contacted and asked to respond to questions regarding the follow-up practice for IA treated with EVT in their department. RESULTS: Responses were obtained from 28/30 (94%) of departments. There was evidence of wide variations in the duration and frequency of follow-up, with a minimum follow-up duration for ruptured IA that varied from 18 months in 5/28 (18%) units to 5 years in 11/28 (39%) of units. Young patient age, previous subarachnoid haemorrhage and incomplete IA occlusion were cited as factors that would prompt more intensive surveillance, although larger and broad-necked IA were not followed-up more closely in the majority of departments. CONCLUSIONS: There is a wide variation in the radiological follow-up of IA treated with EVT in the UK and Ireland. Further standardisation of this aspect of patient care is likely to be beneficial, but further evidence on the behaviour of IA following EVT is required in order to inform this process.

A survey of the radiological follow-up of unruptured intracranial aneurysms in the United Kingdom.

OBJECTIVE: Unruptured intracranial aneurysms (UIA) are common. For many the treatment risks outweigh their risk of subarachnoid haemorrhage and patients undergo surveillance imaging. There is little data to inform if and how to monitor UIAs resulting in widely varying practices. This study aimed to determine the current practice of unruptured UIA surveillance in the United Kingdom. METHODS: A questionnaire was designed to address the themes of surveillance protocols for UIA including when surveillance is initiated, how frequently it is performed, and when it is terminated. Additionally, how aneurysm growth is managed and how clinically meaningful growth is defined were explored. The questionnaire was distributed to members of the British Neurovascular Group using probability-based cluster and non-probability purposive sampling methods. RESULTS: Responses were received from 30 of the 30 (100.0%) adult neurosurgical units in the United Kingdom of which 27 (90.0%) routinely perform surveillance for aneurysm growth. Only four units had a unit policy. The mean patient age up to which a unit would initiate follow-up of a low-risk UIA was 65.4 ± 9.0 years. The time points at which imaging is performed varied widely. There was an even split between whether units use a fixed duration of follow-up or an age threshold for terminating surveillance. Forty percent of units will follow-up patients more than 5 years from diagnosis. The magnitude in the change in size that was felt to constitute growth ranged from 1 to 3mm. No units routinely used vessel wall imaging although 27 had access to 3T MRI capable of performing it. CONCLUSIONS: There is marked heterogeneity in surveillance practices between units in the United Kingdom. This study will help units better understand their practice relative to their peers and provide a framework forplanning further research on aneurysm growth.

Risk factors of chronic shunt dependent hydrocephalus following aneurysmal subarachnoid haemorrhage.

BACKGROUND: Acute and delayed hydrocephalus are common sequelae following aneurysmal subarachnoid haemorrhage. AIMS: To identify factors that may influence cerebrospinal fluid diversion either temporarily or permanently in order to guide clinical judgement. METHODS: Patients treated in our unit between 01/2014 until 12/2017 with aneurysmal SAH were retrospectively analysed to identify significant factors predisposing to CSF diversion. RESULTS: 242 patients were analysed (180F, 62M) with mean age 56 years over 36 months. 31 % patients had EVD inserted and 12 % received shunts. 19 patients had EVDs prior to their shunt. 11.8 % patients received serial lumbar puncture. Higher WFNS (P<0.05) and Fisher grade (P<0.05) were associated with increased rates of EVD insertion and shunting. Higher WFNS and Fisher scores were observed within posterior circulation aneurysms. Lower GCS and higher WFNS had significant correlation towards early shunting (P<0.05). EVD infection predisposes to higher rates of shunt conversion (P<0.05). Factors predisposing to post aneurysmal subarachnoid haemorrhage hydrocephalus and CSF drainage included aneurysm location in posterior circulation (P<0.05), increasing relative need of EVD insertion by 185 % and shunting by 240 %. Basilar tip aneurysms had even higher incidence of shunting (42 % of all posterior circulation aneurysms). Posterior circulation aneurysms had significantly higher risk of requiring EVD insertion, with 48 % of aneurysms in the posterior circulation compared to 25 % in the anterior circulation requiring EVDs (P<0.05). Incidence of posterior circulation aneurysms increases with age (>50(P<0.05)). CONCLUSION: Our study demonstrated factors that may predict chronic post aneurysmal subarachnoid haemorrhage hydrocephalus (PASHH) in patients that will ultimately need timely intervention.

Computed tomographic imaging of meningiomas.

Although magnetic resonance imaging (MRI) has surpassed computerized tomography (CT) as the imaging modality of choice, there are certain instances when CT should be a preoperative requisite for meningioma surgical resection. Given its superior bone definition and the propensity for meningiomas to invade bone (as evidenced by hyperostosis on imaging), CT can be extremely helpful to the surgeon when planning and evaluating postoperatively the extent of bone removal during tumor resection. Advances in CT imaging also allow for visualization of the adjacent arterial and venous vasculature to determine feasibility of resection and likelihood of adjuvant treatments such as radiosurgery to a tumor residuum. For skull base tumors high-resolution CT imaging as part of the standard neuronavigation sequences can help evaluate bony anatomy and planning of surgical approaches, in particular for cranial base tumors. Finally, 3D-CT imaging is important in the design of cranial prostheses, which may be required to repair defects as a result of resection.