Translation of novel imaging techniques into clinical use for patients with epilepsy
Lead Research Organisation:
University College London
Department Name: Institute of Neurology
Abstract
Epilepsy is a common and serious neurological condition. A third of patients have seizures despite medication, which often arise from the temporal lobe. Surgical removal of this part of the brain can control the seizures in 60-70% but may result in impairments of memory, language, vision and mood.
I will use a novel MRI brain scanning technique to look at connections between the temporal lobe and other parts of the brain to determine the effects of epilepsy and neurosurgery on these areas of the brain. Through this I will show how MRI scans before surgery can predict whether a patient will suffer these adverse consequences, so patients can be better informed when making a decision on whether to have surgery.
For those deciding to have surgery, I will compare scans before surgery with those taken 3 and 12 months later to look at how the brain compensates. This information may additionally inform colleagues working in related fields such as brain injury. Finally, I will develop imaging techniques that can be used during surgery specifically to help the surgeon avoid damage to parts of the brain dealing with vision and so improve clinical outcome for the patient.
I will use a novel MRI brain scanning technique to look at connections between the temporal lobe and other parts of the brain to determine the effects of epilepsy and neurosurgery on these areas of the brain. Through this I will show how MRI scans before surgery can predict whether a patient will suffer these adverse consequences, so patients can be better informed when making a decision on whether to have surgery.
For those deciding to have surgery, I will compare scans before surgery with those taken 3 and 12 months later to look at how the brain compensates. This information may additionally inform colleagues working in related fields such as brain injury. Finally, I will develop imaging techniques that can be used during surgery specifically to help the surgeon avoid damage to parts of the brain dealing with vision and so improve clinical outcome for the patient.
Technical Summary
Epilepsy affects over 450,000 people in the UK. One third continue to have seizures despite medication, carrying risks of premature mortality and physical, cognitive and psychosocial morbidity. Temporal lobe epilepsy (TLE) is the most common refractory focal epilepsy. Neurosurgical treatment controls seizures in 60-70% of patients but may adversely affect memory, language and visual fields.
The key research questions are:
1. What are the effects of TLE and anterior temporal lobe resection (ATLR) on the structural connectivity of the temporal lobe to neocortex, particularly language and memory pathways?
2. Can preoperative tractography predict possible adverse effects of ATLR on memory, language and visual fields, and therefore advise the surgeon in minimising these risks?
3. Can pre- and intra-operative tractography be combined with intra-operative neuronavigation to reduce the risk of damage to white matter tracts and thus improve the outcome of epilepsy surgery?
This project will clarify the effects of TLE and neurosurgery on white matter tracts, with prediction of risks and subsequent reduction in individual patients. Conventional MRI sequences do not adequately visualize white matter connections. Diffusion tensor imaging (DTI) is a non-invasive MRI technique which when analysed using tractography can visualize trajectories of white matter tracts.
Male and female subjects undergoing ATLR will have detailed evaluation prior to surgery and 3 and 12 months after surgery comprising MRI scans, including DTI, neuropsychological and neuropsychiatric tests. Control subjects will undergo the same assessment. Tractography will be performed using state-of-the-art Probabilistic Index of Connectivity (PICo) algorithms. Structural connectivity will be compared between the patient groups and control subjects and the changes in the year following surgery evaluated. The extent of connectivity will be correlated with the outcomes observed in memory, language and vision.
At present, up to 24% patients develop a visual field deficit that precludes driving following anterior temporal lobe resection (ATLR). Visualization of the optic radiation using tractography and integration of this information with neurosurgical navigation will reduce this risk and improve patient outcome. Techniques will be developed to combine tractography with the intra-operative neuronavigation system.
Current tractography techniques have limitations in data acquisition and processing. Several new developments to overcome these need implementation and critical evaluation. Serial tractography studies following acquired brain injury or before and after neurosurgery are also lacking. Tractography developments and serial studies that aid the understanding of structural reorganisation within white matter tracts will benefit patient care and inform colleagues in related fields, including acquired brain injury.
The key research questions are:
1. What are the effects of TLE and anterior temporal lobe resection (ATLR) on the structural connectivity of the temporal lobe to neocortex, particularly language and memory pathways?
2. Can preoperative tractography predict possible adverse effects of ATLR on memory, language and visual fields, and therefore advise the surgeon in minimising these risks?
3. Can pre- and intra-operative tractography be combined with intra-operative neuronavigation to reduce the risk of damage to white matter tracts and thus improve the outcome of epilepsy surgery?
This project will clarify the effects of TLE and neurosurgery on white matter tracts, with prediction of risks and subsequent reduction in individual patients. Conventional MRI sequences do not adequately visualize white matter connections. Diffusion tensor imaging (DTI) is a non-invasive MRI technique which when analysed using tractography can visualize trajectories of white matter tracts.
Male and female subjects undergoing ATLR will have detailed evaluation prior to surgery and 3 and 12 months after surgery comprising MRI scans, including DTI, neuropsychological and neuropsychiatric tests. Control subjects will undergo the same assessment. Tractography will be performed using state-of-the-art Probabilistic Index of Connectivity (PICo) algorithms. Structural connectivity will be compared between the patient groups and control subjects and the changes in the year following surgery evaluated. The extent of connectivity will be correlated with the outcomes observed in memory, language and vision.
At present, up to 24% patients develop a visual field deficit that precludes driving following anterior temporal lobe resection (ATLR). Visualization of the optic radiation using tractography and integration of this information with neurosurgical navigation will reduce this risk and improve patient outcome. Techniques will be developed to combine tractography with the intra-operative neuronavigation system.
Current tractography techniques have limitations in data acquisition and processing. Several new developments to overcome these need implementation and critical evaluation. Serial tractography studies following acquired brain injury or before and after neurosurgery are also lacking. Tractography developments and serial studies that aid the understanding of structural reorganisation within white matter tracts will benefit patient care and inform colleagues in related fields, including acquired brain injury.