3 TESLA MR imaging in adults with focal onset epilepsy

SPECT-PET in Epilepsy and Clinical Approach in Evaluation

In epilepsy, a detailed history, blood chemistry, routine electroencephalography, and brain MRI are important for the diagnosis of seizure type or epilepsy syndrome for the decision of appropriate drug treatment. Although antiepileptic drugs are mostly successful for controlling epileptic seizures, 20%-30% patients are resistant to medical treatment and continue to have seizures. In this intractable patient group, surgical resection is the primarily preferred treatment option. This particular group of patients should be referred to the epilepsy center for detailed investigation and further treatment. When the results of electroencephalography, MRI, and clinical status are discordant or there is no structural lesion on MRI, ictal-periictal SPECT, and interictal PET play key roles for lateralization or localization of epileptic region and guidance for the subsequent subdural electrode placement in intractable epilepsy. SPECT and PET show the functional status of the brain. SPECT and PET play important roles in the evaluation of epilepsy sydromes in childhood by showing abnormal brain regions. Most of the experience has been gained with (18)FDG-PET, in this respect. (11)C-flumazenil-PET usually deliniates the seizure focus more smaller than (18)FDG-PET and is sensitive in identifying medial temporal sclerosis. (11)C-alpha-methyl-l-tryptophan is helpful in the differentiation of epileptogenic and nonepileptogenic regions in children especially in tuberous sclerosis and multifocal cortical dysplasia for the evaluation of surgery. Finally, when there is concordance among these detailed investigations, resective surgery or palliative procedures can be discussed individually.

Arterial Spin Labeling Techniques 2009-2014

PURPOSE

Arterial spin labeling (ASL) techniques have been implemented across a diverse range of clinical and experimental applications. This review aims to evaluate the current feasibility of ASL in clinical neuroradiology based on recent improvements to ASL sequences and highlight areas for potential clinical applications.

METHODS AND MATERIALS

In December 2014, a literature search was conducted on PubMed Central, EMBASE, and Scopus using the search terms: "arterial spin labeling, neuroradiology," for studies published between 2009 and 2014 (inclusive). Of 483 studies matching the inclusion criteria, the number of studies using continuous, pseudocontinuous, pulsed, and velocity-selective ASL sequences was 42, 209, 226, and 3, respectively. Studies were classified based on several common clinical applications according to the type of ASL sequence used. Studies using pulsed ASL and pseudo-continuous ASL were grouped based on common sequences.

RESULTS

The number of clinical studies was 264. Numerous studies applied ASL to stroke management (43 studies), drug testing (21 studies), neurodegenerative diseases (40 studies), and psychiatric disorders (26 studies).

CONCLUSIONS

This review discusses several factors hindering the implementation of clinical ASL and ASL-related radiofrequency safety issues encountered in clinical practice. However, a limited number of search terms were used. Further development of robust sequences with multislice imaging capabilities and reduced radiofrequency energy deposition will hopefully improve the clinical acceptance of ASL.

Computational analysis in epilepsy neuroimaging: A survey of features and methods

Epilepsy affects 65 million people worldwide, a third of whom have seizures that are resistant to anti-epileptic medications. Some of these patients may be amenable to surgical therapy or treatment with implantable devices, but this usually requires delineation of discrete structural or functional lesion(s), which is challenging in a large percentage of these patients.

Advances in neuroimaging and machine learning allow semi-automated detection of malformations of cortical development (MCDs), a common cause of drug resistant epilepsy. A frequently asked question in the field is what techniques currently exist to assist radiologists in identifying these lesions, especially subtle forms of MCDs such as focal cortical dysplasia (FCD) Type I and low grade glial tumors. Below we introduce some of the common lesions encountered in patients with epilepsy and the common imaging findings that radiologists look for in these patients. We then review and discuss the computational techniques introduced over the past 10 years for quantifying and automatically detecting these imaging findings. Due to large variations in the accuracy and implementation of these studies, specific techniques are traditionally used at individual centers, often guided by local expertise, as well as selection bias introduced by the varying prevalence of specific patient populations in different epilepsy centers. We discuss the need for a multi-institutional study that combines features from different imaging modalities as well as computational techniques to definitively assess the utility of specific automated approaches to epilepsy imaging. We conclude that sharing and comparing these different computational techniques through a common data platform provides an opportunity to rigorously test and compare the accuracy of these tools across different patient populations and geographical locations. We propose that these kinds of tools, quantitative imaging analysis methods and open data platforms for aggregating and sharing data and algorithms, can play a vital role in reducing the cost of care, the risks of invasive treatments, and improve overall outcomes for patients with epilepsy.

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We introduce common epileptogenic lesions encountered in patients with drug resistant epilepsy.

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We discuss state of the art computational techniques used to detect lesions.

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There is a need for multi-institutional studies that combine these techniques.

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Clinically validated pipelines alongside the advances in imaging and electrophysiology will improve outcomes.

Neuroimaging in refractory epilepsy. Current practice and evolving trends

Identification of the epileptogenic zone is of paramount importance in refractory epilepsy as the success of surgical treatment depends on complete resection of the epileptogenic zone. Imaging plays an important role in the locating and defining anatomic epileptogenic abnormalities in patients with medically refractory epilepsy. The aim of this article is to present an overview of the current MRI sequences used in epilepsy imaging with special emphasis of lesion seen in our practices. Optimisation of epilepsy imaging protocols are addressed and current trends in functional MRI sequences including MR spectroscopy, diffusion tensor imaging and fusion MR with PET and SPECT are discussed.