Functional magnetic resonance imaging: A review of methodological aspects and clinical applications

Abstract

This paper gives an overview of the recent literature on methodological developments of functional magnetic resonance imaging (fMRI) and recent trends in clinical applications. With the recent introduction of high-field systems and methodological developments leading to more robust signal behavior, fMRI is in a transition state from a research modality for use by experts to a standard procedure with useful applications in patient management. Compared to the use in neuroscientific research, which is often based on BOLD techniques alone, the application in patients is distinguished by a multiparametric characterization of the brain using a combination of several techniques. Neuronal fiber tracking based on diffusion anisotropy measurements, in particular, has already turned out to provide relevant supplementary information to the BOLD-based cortical activation maps.

Continuous ASL perfusion fMRI investigation of higher cognition: Quantification of tonic CBF changes during sustained attention and working memory tasks

“…In comparison to positron emission tomography (PET) or single photon emission computed tomography (SPECT), fMRI has higher spatial and temporal resolution, does not involve exposure to ionizing radiation, and is widely available at medical centers. These merits have expanded the applications of fMRI to many clinical areas including presurgical mapping, psychopharmacology, and pediatric neuroimaging (Detre and Floyd, 2001;Hennig et al, 2003;Honey and Bullmore, 2004;Matthews and Jezzard, 2004;Wilke et al, 2003). Blood-oxygenation-level-dependent (BOLD) fMRI has been the method of choice in most occasions, due to its high sensitivity to task-related effects and relative ease of implementation.…”

SmartPhantom — an fMRI simulator

“…From reciprocity theory (16), the signal from a specific voxel (r) with magnetization M(r) is [1] where ω is the Larmor frequency, V is the volume of the voxel, and is the RF magnetic field generated by unit current from receive coil. The magnetization of this voxel will also induce a voltage in the enhancement loop, and its contribution to the final image is resolved through spatial encoding-decoding.…”

“…Functional MRI (fMRI) has emerged as a robust neuroimaging technique that allows the structure and function of the intact brain to be studied (1). Blood Oxygen Level Dependent (BOLD) (2) imaging is the most popular fMRI method and is used as a major tool of studying brain functions.…”

Advanced approach for intraoperative MRI guidance and potential benefit for neurosurgical applications

“…Functional studies were typically conducted one to two days prior to surgery. Unlike morphological data, however, the T2*-weighted EPI blood oxygen level-dependent (BOLD) data cannot be used reliably for registration due to the lack of anatomical information (20). Therefore, an additional T1-weighted data set was acquired with the patient in exactly the same position.…”