This page contains a Flash digital edition of a book.
Surgical Imaging Doris D Wang, MD, PhD,1


Advanced Neuroimaging for Modern Epilepsy Surgery Carlos Santos-Sanchez, MD,2


Paul A Garcia, MD3


and Edward F Chang, MD4


1. Resident, Department of Neurological Surgery and Comprehensive Epilepsy Center; 2. Junior Specialist, Comprehensive Epilepsy Center and Department of Neurology; 3. Professor of Clinical Neurology, Comprehensive Epilepsy Center and Department of Neurology; 4. Assistant Professor of Neurological Surgery and Physiology, Department of Neurological Surgery and Comprehensive Epilepsy Center, University of California, San Francisco


Abstract


Localizing the onset of seizures to guide epilepsy surgery can be notoriously difficult. Modern neuroimaging has revolutionized the field by improving the diagnosis and treatment of epilepsy. In order to ameliorate seizures without causing new neurologic morbidity, many imaging tools have been developed to guide safe and effective resective surgery. In this article, we discuss recent advances in structural imaging using ultrahigh-field magnetic resonance imaging, metabolic functional imaging techniques of positron emission tomography and single positron emission computed tomography, and electrophysiologic imaging using magnetoencephalography. Our goal is to provide an overview of these state-of-the-art imaging modalities, their role in guiding surgery, and how they are incorporated into the pre-surgical evaluation of epilepsy.


Keywords


Epilepsy, imaging, neuroimaging, magnetic resonance imaging, single photon emission computed tomography, positron emission tomography, magnetoencephalography, magnetic source imaging, electroencephalography, epilepsy surgery, temporal lobe epilepsy, malformation of cortical development, outcome


Disclosure: The authors have no conflicts of interest to declare. Acknowledgments: The authors would like to acknowledge Christopher Hess, MD, and Pratik Mukherjee, MD, from the Department of Radiology as well as Spencer Behr, MD, from the Department of Nuclear Medicine for interpretation of imaging studies. The authors would also like to acknowledge the Journal of Neurosurgery and the American Association of Neurological Surgeons for permission to reproduce printed material for the purpose of this publication. Received: November 1, 2011 Accepted: December 5, 2011 Citation: US Neurology, 2011;7(2):169–174 Correspondence: Edward F Chang, MD, Department of Neurological Surgery, University of California, San Francisco, 505 Parnassus Avenue, Box 0112, San Francisco, CA 94143-0112. E: changed@neurosurg.ucsf.edu


When neurosurgeons first attempted to treat epilepsy by means of surgery in the late 1800s, they were operating on ‘invisible’ lesions. Without any imaging or electrophysiological technology, MacEwen and Horsley operated under the principles of functional cerebral localization developed largely by John Hughlings Jackson.1


Epilepsy surgery has come a long way,


as now epileptologists and neurosurgeons are armed with a battery of tools for diagnosis and treatment of epilepsy. These tools have fundamentally changed the way we study and treat this enigmatic disease.


Epilepsy is one of the most common diseases affecting the central nervous system, with a prevalence of 0.5 % and a lifetime cumulative incidence of about 3 %.2


Of those with epilepsy, about 40–50 % become


medically refractory, causing significant impairment to quality of life and increased morbidity, mortality, and healthcare costs. Among these medically refractory cases of epilepsy, many patients are candidates for surgical intervention, which can achieve freedom from seizures in up to 70–80 % of patients.3,4


The goal of epilepsy surgery is to resect


the epileptogenic foci in order to stop or reduce seizure burden without causing significant motor, speech, or cognitive impairments in the patient and, therefore, to improve the patient’s quality of life.


© TOUCH BRIEFINGS 2011


In this article, we discuss advances in imaging techniques used in epilepsy surgery. These techniques include structural imaging techniques with magnetic resonance imaging (MRI), volumetric-based analysis, and high-resolution MRI to assess lesional causes of epilepsy. We also discuss functional imaging modalities that detect changes in brain metabolism during the ictal and interictal period, such as positron emission tomography (PET) and single positron emission computed tomography (SPECT). Finally, we discuss the electrophysiological imaging technique magnetoencephalography (MEG) and its role in the identification of epileptogenic regions in the brain. Imaging is no longer limited to a mere static representation of the brain to acquire structural abnormalities. These new imaging modalities have been developed to capture dynamic brain functions and to yield crucial information about abnormal and normal brain activity. Together, these imaging techniques and future developments will continue to improve our understanding and treatment of epilepsy.


Structural Imaging Temporal Lobe Epilepsy


MRI has become standard practice for any pre-surgical evaluation for epilepsy surgery. MRI can detect relevant structural abnormalities in 85 %


169


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108