Prepared by: S. Steven Hotta, M.D., Ph.D.

Health Technology Assessment:

Number 12

U.S. Department of Health and Human Services Public Health Service Agency for Health Care Policy and Research Rockville, Maryland

July 1998

AHCPR Pub. No. 98-0044

View the Medline Citation and Related Citations using PubMed

The localization of epileptogenic foci that are amenable to curative epilepsy surgery may be accomplished by noninvasive surface electroencephalogram (EEG) recordings, clinical observations, computed tomography (CT), magnetic resonance imaging (MRI), and neuropsychologic tests. Other tests, such as invasive EEG, ¹⁸F-fluoro-deoxyglucose-positron-emission tomography (FDG-PET or PET) scans, and single-photon-emission computed tomography (SPECT) scans, have also been used at various epilepsy centers to help identify candidates who might benefit from such surgery.

Interictal PET scans have demonstrated hypometabolism in areas concordant with the epileptogenic foci indicated by other diagnostic tests such as EEG and MRI. However, PET scans have also shown no abnormality in many patients with EEG-indicated epileptogenic foci; in others, the scans have shown abnormal metabolism in areas that were discordant with the epileptogenic foci. Although substitution of the noninvasive PET scan for the invasive EEG recordings would be desirable, the available data were insufficient to determine whether PET scans might serve as a reliable substitute for EEG. A positive PET scan might contribute independent information for identifying the epileptogenic site but could be noncontributory or confusing when hypometabolism is not seen or is seen in presumably normal brain areas. It is not evident from the data in the literature to what extent confirmatory PET scan findings might contribute to the management of patients with complex partial seizures.

The Center for Practice and Technology Assessment (CPTA) evaluates the risks, benefits, and clinical effectiveness of new or established medical technologies. In most instances, assessments address technologies that are being reviewed for purposes of coverage by federally funded health programs.

The CPTA assessment process includes a comprehensive review of the medical literature and emphasizes broad and open participation from within and outside the Federal Government. A range of expert advice is obtained by widely publicizing the plans for conducting the assessment through publication of an announcement in the Federal Register and solicitation of input from Federal agencies, medical specialty societies, insurers, and manufacturers. The involvement of these experts helps ensure inclusion of the experienced and varying viewpoints needed to round out the data derived from individual scientific studies in the medical literature.

The CPTA analyzed and synthesized data and information received from experts and the scientific literature. The results are reported in this assessment. Each assessment represents a detailed analysis of the risks, clinical effectiveness, and uses of new or unestablished medical technologies. If an assessment has been prepared to form the basis for a coverage decision by a federally financed health care program, it serves as the Public Health Service's recommendation to that program and is disseminated widely.

The CPTA is one component of the Agency for Health Care Policy and Research (AHCPR), Public Health Service, Department of Health and Human Services.

Douglas B. Kamerow, M.D., M.P.H., Director, Center for Practice and Technology Assessment
John M. Eisenberg, M.D., Administrator, Agency for Health Care Policy and Research

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Acc:: Accuracy

ART:: Arrhythmia research technology

BBB:: Bundle branch block

CAD:: Coronary artery disease

CAST:: Cardiac arrhythmia suppression trials

CFR:: Case fatality rate

CHF:: Congestive heart failure

CI:: Confidence interval

CT:: Computed tomography

dQRS:: Duration of the filtered QRS complex > 106 ms

ECG:: Electrocardiogram

EEG:: Electroencephalogram/electroencephalography

FD:: Frequency domain

FDA:: Food and Drug Administration

FDG-PET:: Fluorodeoxyglucose-positron-emission tomography

FU:: Followup

HCFA:: Health Care Financing Administration

IDC:: Idiopathic dilated cardiomyopathy

i-EEG:: Invasive electroencephalography

LAS:: Low amplitude signal

LVEF:: Left ventricular ejection fraction

LVH:: Left ventricular hypertrophy

MeSH:: Medical subject heading

MI:: Myocardial infarction

MRI:: Magnetic resonance imaging

MUGA:: Multigated acquisition

NPV:: Negative predictive value

NS:: Not stated

NSR:: Normal sinus rhythm

NYHA:: New York Heart Association

PES:: Programmed electrical stimulation

PET:: Positron-emission tomography

PPV:: Positive predictive value

RMS:: Root mean square voltage during the last 40 ms of the QRS complex <25 µV

RNV:: Radionuclide ventriculography

SAEGG:: Signal-averaged electrocardiography

SD:: Sudden death

1SD:: One standard deviation

Se:: Sensitivity

s-EEG:: Surface/sphenoidal electroencephalography

Sp:: Specificity

SPECT:: Single-photon-emission computed tomography

STA:: Spectral turbulence analysis

TD:: Time domain

VAT:: Ventricular activation time

VF:: Ventricular fibrillation

VLP:: Ventricular late potentials

VT:: Ventricular tachyarrhythmia