The usefulness and limitations of diffusion tensor imaging – a review study

Abstract

Diffusion tensor tractography (DTI) has been used for planning of a brain pathology surgeries. Knowledge about the distances between neural tracts and brain tumours is believed to increase the patient safety and implies the extent of resection. The aim of the study was to demonstrate the contemporary possibilities and the clinical usefulness of DTI. Following the explanation of the technical basics of DTI, we presented the drawbacks and limitations of this visualisation technique. The most commonly outlined tracts are corticospinal tract (CST), arcuate fasciculus (AF) and frontal aslant tract (FAT). Tumour located in frontal, parietal or temporal lobe can affect the course of the CST. There are two basic possibilities to visualise CST: deterministic and probabilistic. The usefulness of DTI seems limited in imaging the neoplasms of either frontal or temporal region causing aphasia, which infiltrate the AF or the FAT. This limitation is probably related to divergent and patient-specific location of functional speech areas. Acquisition disturbances, ill-defined mathematical algorithms, surgery-related brain shift and defining wrong non-functional brain area are the sources of DTI inaccuracy, which is limiting its clinical application.

Tractography Alterations in the Arcuate and Uncinate Fasciculi in Post-Stroke Aphasia

“…Indeed, increased FA has been reported following rehabilitation, which may be due to remodeling of white matter motor pathways [ 30 , 31 ]. Tractography can also be used to assess non-motor routes [ 12 , 32 , 33 ]. Damage to the AF is associated with the occurrence of conductive aphasia, which is characterized by a strongly limited or inability to repeat words heard and a lack of control over active speech [ 34 ].…”

“…The AF is a bundle of associative fibers that connect Wernicke’s area, which is responsible for sensory aspects of speech, with Broca’s area, which is responsible for motor aspects of speech. This fiber bundle is largely responsible for central speech control by coordinating information between the motor and sensory speech areas [ 12 ]. The uncinate fasciculus as a hook fascicle connecting the prefrontal cortex and temporal lobe.…”

Tractography-guided surgery of brain tumours: what is the best method to outline the corticospinal tract?

“…For neurosurgeons, the fibres originating at the precentral gyrus are the most crucial while planning any surgical access near the pyramidal tracts [7,8,19,20]. A study suggests that the remainder of the CST fibres come from the FL, mainly from the superior frontal gyrus [3].…”

“…Yet, they provide only general information about the brain's pathology and the surrounding structures. Diffusion tensor imaging (DTI)-which provides a quick and noninvasive method for visualising structural changes of the white matter-can be used for visualisation of the CST [7,8]. This technique not only plays an important role in neurosurgical planning but may predict the extent of safe resection [9][10][11].…”

Structural Connectivity Reorganization Based on DTI after Cingulotomy in Obsessive–Compulsive Disorder

“…The basis of its operation is detecting Brownian motion. These are diffusive movements of water molecules in the extracellular space [17][18][19]. The degree of orientation of diffusion of water molecules is called fractional anisotropy (FA).…”