Robert Joshua Dym MD, Presenter: Nothing to Disclose

Michael L. Lipton MD, PhD, Abstract Co-Author: Nothing to Disclose

The quest to determine the feasibility of replacing the invasive Wada test (intracarotid amytal testing) with functional MRI (fMRI) in the pre-operative determination of hemispheric language dominance has been hampered by the small size and diverse approaches of many of the studies. We therefore performed a meta-analysis of the extant literature on the topic, toward resolving this question.

A structured Medline search was conducted to identify all studies that compared fMRI to the Wada test for determining hemispheric language dominance prior to brain surgery. A meta-analysis was then performed, pooling weighted data from all studies fulfilling the search criteria. Results were classified as being either typical (left hemispheric language dominance) or atypical (right hemispheric language dominance or bilateral language representation) for each patient case.

Twenty-three studies, comprising 453 patients evaluated with both the Wada test and fMRI, met inclusion criteria. A high degree of concordance was found for language dominance determined by Wada and fMRI. Using the Wada test as the reference “gold standard” in the assessment of hemispheric language dominance, the sensitivity and specificity of fMRI for atypical language dominance were 94.3% (95% confidence interval, 68.2-100%) and 95.7% (95% confidence interval, 80.4-100%), respectively.

fMRI provides an excellent, non-invasive alternative to the Wada test for the pre-operative assessment of hemispheric language dominance. While an atypical result may necessitate further testing, the finding of typical language dominance by fMRI is highly specific and may allow treatment to proceed without need for the invasive Wada test.

fMRI should be considered for the initial pre-operative evaluation of hemispheric language dominance, and may obviate the need for the invasive Wada test.

Dym, R, Lipton, M, Is fMRI Assessment of Hemispheric Language Dominance as Good as the Wada Test: A Meta-analysis.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6018491.html