Neuroimaging in Epilepsy: Diagnostic Strategies in Partial Epilepsy

ABSTRACT

The diagnostic evaluation of the patient with partial or localization-related epilepsy is designed to identify treatment strategies that will permit the individual to be seizure-free. The use of magnetic resonance imaging (MRI) has been pivotal in elucidating the presence of an epileptogenic pathological alteration that may coexist with the site of seizure onset. There are compelling data that MRI is of significant diagnostic and prognostic importance in patients with partial epilepsy. Patients with MRI-negative partial epilepsy may be candidates for additional neuroimaging techniques including positron emission tomography, MR spectroscopy, and single photon emission tomography. Contemporary innovations with peri-ictal imaging may allow identification of the epileptogenic zone in patients with normal MRI scans. This discussion will focus on the management of the adult patient with seizures and epilepsy, emphasizing the neuroimaging evaluation and treatment of patients with medically refractory seizure disorders.

KEYWORDS

MRI - seizures - epilepsy - partial epilepsy - SISCOM

REFERENCES

• 1 Nguyen D K, Spencer S S. Recent advances in the treatment of epilepsy.  Arch Neurol. 2003;  60 929-935
• 2 Cascino G D. Surgical treatment for epilepsy.  Epilepsy Res. 2004;  60 179-186
• 3 Camfield P R, Camfield C S. Antiepileptic drug therapy: when is epilepsy truly intractable?.  Epilepsia. 1996;  37(S1) S60-S65
• 4 Widdess-Walsh P, Devinsky O. Antiepileptic drug resistance and tolerance in epilepsy.  Rev Neurol Dis. 2007;  4 194-202
• 5 Hauser A, Hesdorffer D. Prognosis. In: Hauser WA, Hesdorffer DC Epilepsy: Frequency, Causes and Consequences. New York, NY; Demos 1990: 197-243
• 6 Radhakrishnan K, So E L, Silbert P L et al.. Predictors of outcome of anterior temporal lobectomy for intractable epilepsy: a multivariate study.  Neurology. 1998;  51 465-471
• 7 Dupont S, Tanguy M L, Clemenceau S et al.. Long-term prognosis and psychosocial outcomes after surgery for MTLE.  Epilepsia. 2006;  47 2115-2124
• 8 Spencer S S, Berg A T, Vickrey B G et al.. Predicting long-term seizure outcome after resective epilepsy surgery: the multicenter study.  Neurology. 2005;  65 912-918
• 9 Sharma A K, Reams R Y, Jordan W H et al.. Mesial temporal lobe epilepsy: pathogenesis, induced rodent models and lesions.  Toxicol Pathol. 2007;  35 984-999
• 10 Cascino G D, Boon P AJM, Fish D R. Surgically remediable lesional syndromes. In: Engel J Jr Surgical Treatment of the Epilepsies. 2nd ed. New York, NY; Raven Press 1993: 77-86
• 11 Awad I A, Rosenfeld J, Ahl H, Hahn J F, Luders H. Intractable epilepsy and structural lesions of the brain: mapping, resection strategies, and seizure outcome.  Epilepsia. 1991;  32 179-186
• 12 Cohen-Gadol A A, Wilhelmi B G, Collignon F et al.. Long-term outcome of epilepsy surgery among 399 patients with nonlesional seizure foci including mesial temporal lobe sclerosis.  J Neurosurg. 2006;  104 513-524
• 13 Jack C R, Sharbrough F W, Twomey C K et al.. Temporal lobe seizure: lateralization with MR volume measurements of the hippocampal formation.  Radiology. 1990;  175 423-429
• 14 Jackson G D, Berkovic S F, Tress B M et al.. Hippocampal sclerosis can be readily detected by magnetic resonance imaging.  Neurology. 1990;  40 1869-1875
• 15 Cascino G D, Trenerry M R, So E et al.. Routine EEG and temporal lobe epilepsy: relation to long-term EEG monitoring, quantitative MRI, and operative outcome.  Epilepsia. 1996;  37 651-656
• 16 Mosewich R K, So E L, O'Brien T J et al.. Factors predictive of the outcome of frontal lobe epilepsy surgery.  Epilepsia. 2000;  41 843-849
• 17 Cambier D M, Cascino G D, So E L, Marsh W R. Video-EEG monitoring in patients with hippocampal atrophy.  Acta Neurol Scand. 2001;  103 231-237
• 18 Cascino G D, Jack Jr C R, Parisi J E et al.. MRI in the presurgical evaluation of patients with frontal lobe epilepsy and children with temporal lobe epilepsy: pathological correlation and prognostic importance.  Epilepsy Res. 1992;  11 51-59
• 19 Palmini A, Andermann F, Olivier A et al.. Focal neuronal migrational disorders and intractable partial epilepsy: results of surgical treatment.  Ann Neurol. 1991;  30 750-757
• 20 Madhavan D, Schaffer S, Yankovsky A. Surgical outcome in tuberous sclerosis complex: a multicenter survey.  Epilepsia. 2007;  48 1625-1628
• 21 Spencer S S. The relative contributions of MRI, SPECT and PET imagining in epilepsy.  Epilepsia. 1994;  35 S72-S89
• 22 Knowlton R C. The role of FDG-PET, ictal SPECT, and MEG in the epilepsy surgery evaluation.  Epilepsy Behav. 2006;  8 91-101
• 23 Henry T R, Babb T L, Engel Jr J et al.. Hippocampal neuronal loss and regional hypometabolism in temporal lobe epilepsy.  Ann Neurol. 1994;  36 925-927
• 24 Pillai J J, Williams H T, Faro S. Functional imaging in temporal lobe epilepsy.  Semin Ultrasound CT MR. 2007;  28 437-450
• 25 Uijl S G, Leijten F S, Arends J B et al.. The added value of [18F]-fluoro-D-deoxyglucose positron emission tomography in screening for temporal lobe epilepsy surgery.  Epilepsia. 2007;  48 2121-2129
• 26 Willmann O, Wennberg R, May T, Woermann F G, Pohlmann-Eden B. The contribution of 18F-FDG PET in preoperative epilepsy surgery evaluation for patients with temporal lobe epilepsy: a meta-analysis.  Seizure. 2007;  16 509-520
• 27 Dedeurwaerdere S, Jupp B, O'Brien T J. Positron emission tomography in basic epilepsy research: a view of the epileptic brain.  Epilepsia. 2007;  48(S4) 56-64
• 28 Sata Y, Matsuda K, Mihara T et al.. Quantitative analysis of benzodiazepine receptor in temporal lobe epilepsy: [¹²⁵I]Iomazenil autoradiographic study of surgically resected specimens.  Epilepsia. 2002;  43 1039-1048
• 29 Juhasz C, Chugani D C, Muzik O et al.. Alpha-methyl-L-tryptophan PET detects epileptogenic cortex in children with intractable epilepsy.  Neurology. 2003;  60 960-968
• 30 Cendes F, Caramanos Z, Andermann F, Dubeau F, Arnold D L. Proton magnetic resonance spectroscopy imaging and magnetic resonance imaging volumetry in the lateralization of temporal lobe epilepsy.  Ann Neurol. 1997;  42 737-746
• 31 Kuzniecky R, Hugg J W, Hetherington H et al.. Relative utility of 1H spectroscopic imaging and hippocampal volumetry in the lateralization of mesial temporal lobe epilepsy.  Neurology. 1998;  51 66-71
• 32 O'Brien T J, So E L, Mullan B P et al.. Subtraction ictal SPECT co-registered to MRI improves clinical usefulness of SPECT in localizing the surgical seizure focus.  Neurology. 1998;  50 445-454
• 33 O'Brien T J, So E L, Mullan B P et al.. Extent of resection of the ictal subtraction SPECT focus is an important determinant of epilepsy surgery outcome.  Epilepsia. 1996;  37(suppl 5) S182
• 34 O'Brien T J, O'Connor M K, Mullan B P et al.. Subtraction ictal SPECT co-registered to MRI in partial epilepsy: description and technical validation of the method with phantom and patients studies.  Nucl Med Commun. 1998;  19 31-45
• 35 So E L. Integration of EEG, MRI and SPECT in localizing the seizure focus for epilepsy surgery.  Epilepsia. 2000;  41(S3) S48-S54
• 36 O'Brien T J, So E L, Mullan B P et al.. Subtraction SPECT co-registered to MRI improves postictal localization of seizure foci.  Neurology. 1999;  52 137-146
• 37 Brinkmann B H, O'Brien T J, Webster D B et al.. Voxel significance mapping using local image variances in subtraction ictal SPET.  Nucl Med Commun. 2000;  21 545-551
• 38 O'Brien T J, Brinkmann B H, Mullan B P et al.. Comparative study of 99m Tc-ECD and 99m Tc-HMPAO for SPECT: qualitative and quantitative analysis.  J Neurol Neurosurg Psychiatry. 1999;  66 331-339
• 39 So E L, O'Brien T J, Brinkmann B H et al.. The EEG evaluation of single photon emission computed tomography abnormalities in epilepsy.  J Clin Neurophysiol. 2000;  17 10-28
• 40 O'Brien T J, So E L, Mullan B P et al.. Subtraction peri-ictal SPECT is predictive of extratemporal epilepsy surgery outcome.  Neurology. 2000;  55 1668-1677
• 41 Fessler J A, Cascino G D, So E L et al.. Subtraction ictal SPECT co-registered to MRI (SISCOM) in the evaluation for repeat epilepsy surgery.  Neurology. 2000;  54(suppl 3) A4
• 42 Cascino G D, Buchhalter J R, Mullan B P, So E L. Ictal SPECT in nonlesional extratemporal epilepsy.  Epilepsia. 2004;  45(Suppl 4) 32-34
• 43 Wetjen N M, Cascino G D, Fessler A J. Subtraction ictal single-photon emission computed tomography coregistered to magnetic resonance imaging in evaluating the need for repeated epilepsy surgery.  J Neurosurg. 2006;  105 71-76