Authors' objectives:

The aim of this review is to assess the evidence of the clinical usefulness of functional magnetic resonance imaging (fMRI) of brain pathologies.

Authors' results and conclusions: Only some isolated reports and few patients (less than 30) were found for the following applications: - To detect functional areas in patients prior to surgery of tumors and vascular malformations. - In case of an already known focal lesion, to correlate the extent of the dysfunction with the affected area. - To assess brain reordering tending to complement the function involved in patients with specific deficits: attention deficit disorder, maniac depressive disorder, phobic syndromes, disorders of the language, etc. - To detect brain infarction during onset and to monitor functional recovery post-event. - To objectively prove changes in the neuronal activity in response to functional surgery of Parkinson's disease. - To monitor response to drug therapy in Alzheimer's disease. In all the previous indications, the existing evidence is not considered sufficient to support its use as common practice. A greater number of articles were found for the following two applications: A. fMRI as a neurosurgical planning tool for refractory epilepsy surgery: fMRI is presented as a presurgical assessment test for patients with temporal lobe epilepsy refractory to medical treatment as adjuvant or substitute of the classical gold standard tests (Wada's test and cortical electrical stimulation). Most studies (cross sectional) included few patients (between 7 and 32) and did not report test operating features, suggesting high sensitivity and moderate specificity. There is no evidence of good quality supporting the use of fMRI as a presurgical test. B. fMRI for the diagnosis of Alzheimer's disease (AD): All the tests, cross sectional most of them, included few patients (less than 30) and showed evidence of which brain areas are suffering activation deficit by fMRI, in those patients with early, intermediate or advanced AD, in patients with mild cognitive impairment and patients with high risk of AD. In patients with clinically diagnosed AD, fMRI allows to assess which the brain areas mostly affected by the disease are. In the group of patients with mild cognitive impairment or early AD, the real prognostic value of the images observed by fMRI is still to be determined in long-term prospective studies. Currently, it is not possible to determine the efficacy of fMRI in AD.

Authors' recommendations: Nowadays, functional magnetic resonance imaging is still under research for all its possible applications. Its major problem seems to be its low technical specificity which does not allow to accurately distinguish main from secondary activation areas. On the other hand, the technique is very sensitive to variations in the type of stimulus used to achieve cortical activation. It is still to be determined which stimulus is more adequate for each pathology. Due to the lack of appropriate evidence on the usefulness of fMRI for its different applications, it is still considered under research and it is not usually covered by different health systems.

Authors' methods: Overview

Project Status: Completed

URL for project: http://www.iecs.org.ar/

Year Published: 2005

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Argentina

Organisation Name: Institute for Clinical Effectiveness and Health Policy

Contact Address: Dr. Emilio Ravignani 2024, Buenos Aires - Argentina, C1414 CABA

Contact Name: info@iecs.org.ar

Contact Email: info@iecs.org.ar

Copyright: Institute for Clinical Effectiveness and Health Policy (IECS)