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A Pipeline for 3D Multimodality Image Integration and Computer-assisted Planning in Epilepsy Surgery

Epilepsy surgery is challenging and the use of 3D multimodality image integration (3DMMI) to aid presurgical planning is well-established. Multimodality ...

UCL Institute of Neurology

Spinal cord arterio-venous malformations (AVMs) are rare and the diagnosis is often delayed or missed. We describe two cases presenting in different ways, as subarachnoid haemorrhage (SAH) or myelopathy. A catheter angiogram confirmed the diagnosis following which they were treated with coil occlusion or embolisation, or a combination of both, without any complications.

Spinal cord arterio-venous malformations in children: a rare but important diagnosis.

It is proposed that radiofrequency thermocoagulation (RFT) under general anaesthesia without waking the patient intra-operatively, which is usually performed to confirm lesion location, will reduce the peri-operative discomfort and anxiety suffered by patients.

Radiofrequency thermocoagulation for trigeminal neuralgia without intra-operative patient waking.

Since intracranial electrode implantation has limited spatial sampling and carries significant risk, placement has to be effective and efficient. Structural and functional imaging of several different modalities contributes to localising the seizure onset zone (SoZ) and eloquent cortex. There is a need to summarise and present this information throughout the pre/intra/post-surgical course.

Feasibility of multimodal 3D neuroimaging to guide implantation of intracranial EEG electrodes.

This review summarises exciting recent and forthcoming advances that will impact on the surgical management of epilepsy in the near future. This does not cover the current accepted diagnostic methodologies or surgical treatments that are routinely practiced today. The content of this review was derived from a PubMed literature search, using the key words 'Epilepsy Surgery', 'Neuromodulation', 'Neuroablation', 'Advances', between 2010 and November 2013.

Advances in epilepsy surgery.

Stereoelectroencephalography (SEEG) is an invasive diagnostic procedure in epilepsy surgery that is usually implemented with frame-based methods.

A novel method for implementation of frameless StereoEEG in epilepsy surgery.

StereoEEG implantation is performed in patients with epilepsy to determine the site of the seizure onset zone. Intracranial haemorrhage is the most common complication associated to implantation carrying a risk that ranges from 0.6 to 2.7%, with significant associated morbidity. SEEG planning is done pre-operatively to identify avascular trajectories for the electrodes. In current practice neurosurgeons have no assistance in the planning of the electrode trajectories. There is great interest in developing computer assisted planning systems that can optimize the safety profile of electrode trajectories, maximizing the distance to critical brain structures. In this work, we address the problem of blood vessel extraction for SEEG trajectory planning. The proposed method exploits the availability of multi-modal images within a trajectory planning system to formulate a vessel extraction framework that combines the scale and the neighbouring structure of an object. We validated the proposed method in twelve multi-modal patient image sets. The mean Dice similarity coefficient (DSC) was 0.88 ± 0.03, representing a statistically significantly improvement when compared to the semi-automated single rater, single modality segmentation protocol used in current practice (DSC = 0.78 ± 0.02).

SEEG trajectory planning: combining stability, structure and scale in vessel extraction.

We present a single-center prospective study, validating the use of 3D multimodality imaging (3 DMMI) in patients undergoing intracranial electroencephalography (IC-EEG).

Utility of 3D multimodality imaging in the implantation of intracranial electrodes in epilepsy.

Brain vessels are among the most critical landmarks that need to be assessed for mitigating surgical risks in stereo-electroencephalography (SEEG) implantation. Intracranial haemorrhage is the most common complication associated with implantation, carrying significantly associated morbidity. SEEG planning is done pre-operatively to identify avascular trajectories for the electrodes. In current practice, neurosurgeons have no assistance in the planning of electrode trajectories. There is great interest in developing computer-assisted planning systems that can optimise the safety profile of electrode trajectories, maximising the distance to critical structures. This paper presents a method that integrates the concepts of scale, neighbourhood structure and feature stability with the aim of improving robustness and accuracy of vessel extraction within a SEEG planning system.

Stability, structure and scale: improvements in multi-modal vessel extraction for SEEG trajectory planning.

To determine whether resection of areas with evidence of intense, synchronized neural firing during seizures is an accurate indicator of postoperative outcome.

Seizure localization using ictal phase-locked high gamma: A retrospective surgical outcome study.

In response: Talairach methodology in the era of 3D multimodal imaging: "The song remains the same," but catchier, and therefore more helpful for clinical decision making and surgical planning in epilepsy surgery.

Primary brain tumors are common causes of focal epilepsy, accounting for 5% of new-onset seizures in adults and over 10% of lesional focal epilepsies. These epilepsies are often refractory to medical treatment, and high rates of seizure freedom can be achieved with gross total resections. However, the management strategy is not straightforward, and should be decided on a case-by-case basis in a multidisciplinary team, considering the natural history of the tumor, the likelihood of seizure freedom following surgical resection, the risks of surgery, and the impact of seizures on quality of life. In this review, the authors summarize the crucial factors that help to decide how to manage this challenging patient group.

Tumors in Epilepsy.

Several studies have suggested an asymmetry in Meyer's loop in individuals, with the left loop anterior to the right. In this study we test the hypothesis that there is an association between Meyer's loop asymmetry (MLA) and language lateralisation.

Meyer's loop asymmetry and language lateralisation in epilepsy.

OBJECT The objective of this study was to evaluate the clinical utility of multitrajectory computer-assisted planning software (CAP) to plan stereoelectroencephalography (SEEG) electrode arrangements. METHODS A cohort of 18 patients underwent SEEG for evaluation of epilepsy at a single center between August 2013 and August 2014. Planning of electrodes was performed manually and stored using EpiNav software. CAP was developed as a planning tool in EpiNav. The user preselects a set of cerebral targets and optimized trajectory constraints, and then runs an automated search of potential scalp entry points and associated trajectories. Each trajectory is associated with metrics for a safety profile, derived from the minimal distance to vascular structures, and an efficacy profile, derived from the proportion of depth electrodes that are within or adjacent to gray matter. CAP was applied to the cerebral targets used in the cohort of 18 previous manually planned implantations to generate new multitrajectory implantation plans. A comparison was then undertaken for trajectory safety and efficacy. RESULTS CAP was applied to 166 electrode targets in 18 patients. There were significant improvements in both the safety profile and efficacy profile of trajectories generated by CAP compared with manual planning (p < 0.05). Three independent neurosurgeons assessed the feasibility of the trajectories generated by CAP, with 131 (78.9%) of 166 trajectories deemed suitable for implementation in clinical practice. CAP was performed in real time, with a median duration of 8 minutes for each patient, although this does not include the time taken for data preparation. CONCLUSIONS CAP is a promising tool to plan SEEG implantations. CAP provides feasible depth electrode arrangements, with quantitatively greater safety and efficacy profiles, and with a substantial reduction in duration of planning within the 3D multimodality framework.

Mark Nowell

Department of Clinical and Experimental Epilepsy

UCL Institute of Neurology

A Pipeline for 3D Multimodality Image Integration and Computer-assisted Planning in Epilepsy Surgery

Mark Nowell

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Department of Clinical and Experimental Epilepsy

UCL Institute of Neurology

A Pipeline for 3D Multimodality Image Integration and Computer-assisted Planning in Epilepsy Surgery

Department of Clinical and Experimental Epilepsy