Clinical BOLD fMRI and DTI: Artifacts, tips, and tricks

Abstract

DTI and BOLD functional MRI techniques suffer from many different types of artifacts. These artifacts can have a technical origin like susceptibility artifacts in specific brain regions or vibration and eddy-current artifacts, but they can also be related to physiology. The draining vein activation observed in the neighborhood of functionally active regions or flow artifacts are such physiologically induced artifacts. In clinical fMRI, there are also several specific effects. These can be pathology-induced reduction or absence of brain activation in the vicinity of lesions, which can lead to false interpretation of the resulting fMRI maps. As patients are most of the time ill, the pharmaceuticals they are taking can influence the BOLD signal, and the same applies to a lack of cooperation during the scan and head motion which is also detrimental for DTI acquisition. The success rate in clinical fMRI/DTI protocols is clearly related to the clinician’s/technician’s ability to recognize and cope with these technical, physiological, and patient- induced artifacts.