Functional MRI (fMRI) language localization – conjunction display
Blood oxygen level dependent functional MRI, or BOLD fMRI, is an advanced MRI technique in which level of oxygen present in an area of the brain is used to map out what parts of the brain are activated in specific tasks. In this method, repeated imaging of the brain can be performed while the patient performs a task, and the level of oxygenation changes, showing which parts of the brain are most activated.
A key application of fMRI is mapping of language areas, or language localization, for surgical planning. The patient will perform more than 1 language task while in the scanner, and the activation data is overlaid on anatomic imaging (like conventional T1 or T1 postcontrast imaging). This is used to determine which side of the brain is language dominant as well as where exactly important language areas, including Broca’s and Wernicke’s areas, are located. This way they can be avoided in complex surgical procedures. However, sometimes results can be difficult to interpret because of the high number of images and high amounts of noise.
In this video, Dr. Michael Hoch demonstrates how use a conjunction technique to increase sensitivity for mapping language areas. In this method, all the language paradigms are overlaid on a single set of images using different colors. This increases the visibility of otherwise hard to see areas, increasing reader confidence.
The level of this lecture is appropriate for radiology residents, radiology fellows, and trainees in other specialties who have an interest in advanced MRI techniques such as diffusion tensor imaging (DTI) tractography, functional MRI (fMRI), and surgical planning.
For more information, see the whole video playlist on Advanced MRI.