Index of Terminology

Continuously updated 3D-data, allowing for e.g. detection of movement in 3D-images.

The contact between ultrasound transducer and brain tissue which is necessary to facilitate the transmission and receival of acoustic signal. This can be achieved through e.g. ultrasound gel or water.

Amplitude Mode scan; one-dimensional sample of a certain depth of the tissue.

Procedure where a patient is operated on the brain while being awake, facilitating communication, the performance of functional task etc.

The biological substrate deals with the underlying physiological process which is used as a measure of functionality by each of the techniques.

The interplay of changes in Cerebral Blood Volume (CBV), Cerebral Blood Flow (CBF) and vessel diameter (vasoconstriction/vasodilatation).

A computer-based system that interfaces with the central nervous system to acquire signals, analyzes them, and translates them into commands that are relayed to an output device to perform a desired action.

The brain tissue’s ability to produce specific functional tasks or states, such as moving the hand or repeating a word.

Brightness Mode scan; 2D, cross-sectional image produced by scanning the beam across the sample and assembling a collection of neighboring A-scans.

Molecules in the tissue that absorb a particular wavelength of light.

Simultaneous detection by two opposing detectors

The depth of the brain tissue which can be reached by a penetrative technique.

The possibility to spatially discern the signal along the depth-axis.

The change in frequency of a wave caused by motion, e.g. movement of a red blood cell..

The extent to which a technique can be applied without previous training or expertise.

Electrical stimulation (ESM)-induced spread of current which may lead to 1) activation of adjacent functional areas, represented by clinical manifestations not representative of the stimulus site or 2) epileptic seizure elicitation.

Artifacts caused due to external injection of electrical current into the tissue.

Imaging techniques which are based on (direct) sampling.

Area of the brain that speaks to readily identifiable neurological function and, if injured, result in a disabling neurological deficit.

(Part of) the brain with skull and dura removed.

The field of view refers to the extent of the tissue which can be covered by the imaging technique.

The process of finding and visualizing the borders of a particular functional brain area in the brain

A regional increase of blood flow in response to local neural activation.

Any technique which has the ability to visualize functionality of brain tissue in a non-invasive manner.

Visual representation of functional areas, often in the form of a color-coded map representing parameters such as coefficient of correlations, superimposed over a morphological or structural image

Any technique which has the ability to detect functionality of brain tissue

The amount of time necessary to generate the full functional volume of interest. This should be considered as the approximate time needed in the OR to acquire a functional map which can be used for surgical decision-making.

Interference is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude.

The extent to which a technique 1) needs to penetrate the brain tissue to sample brain functionality to and/or 2) requires invasive practices for its functionality (e.g. administering a radioactive tracer for fPET).

Determining the sources of a signal, e.g. the magnetic field in case of MEG, when measured extracranially.

Maximal survival benefit by removal of tumor bulk with minimal risk of pot-operative neurological deficit.

Imaging techniques which are based on sampling of one or more of the biological substrates involved in the process of neurometabolic coupling.

The extent to which the imaging technique can be moved.

The extent to which a technique can be used in concomitance with other techniques. Some techniques are inherently more difficult to combine with others, due to for example electrical or susceptibility artefacts.

Interruption of a functional task being performed during electrocortical stimulation mapping (ESM).

The mechanisms responsible for linking (electrical) neuronal activity to corresponding changes in consumption of metabolites such as oxygen and glucose.

The mechanisms responsible for linking (electrical) neuronal activity to corresponding changes in blood dynamics.

Pathological mechanisms due to which  (electrical) neuronal activity is no longer coupled to corresponding changes in blood dynamics.

Technique which does not require physical penetration of brain tissue.

The depth to which an imaging technique can penetrate brain tissue.

Imaging modality which makes use of the photo-acoustic effect: laser pulses delivered to tissue cause transient thermoelastic expansion, and as such, ultrasonic emission which is detected by ultrasound transducers.

Production of a response (i.e. language/motor movement) during electrocortical stimulation mapping (ESM).

An imaging technique which has close to no delays (instantaneous) when acquiring and producing functional images.

Imaging based on uncovering inherent patterns of network connectivity within the brain signal without a known input.

The method used by a technique to sample the biological substrate of interest. This can be superficial sampling, or penetrative sampling, either with or without depth resolution. Sampling can be achieved of the full field of view at once, or by combining multiple subsamples, such as A-scans.

The spatial resolution of a technique concerns the physical dimensions that the technique’s smallest unit of measure represents. In case of images, this would concern the physical dimensions represented by a single pixel within the image.

Speckle is the results of the interference of many waves of the same frequency which added together result in a wave with a randomly varying intensity.

Any technique which has the ability to visualize structure and/or morphology of brain tissue.

The course of the surgical intervention and the conventional steps in the surgical procedure.

Artifacts caused due to differences in magnetic susceptibilities of tissues or materials. In MRI, this is characterized by geometric distortion, including brighter or darker areas.

Imaging based on providing the brain with a known input (a functional task pattern) to correlate the sampled signal to.

The temporal resolution tells us with which frequency a technique is able to sample the biological substrate which underlies a technique.

Imaging through section of tissue using any kind of penetrating wave.

A technique which has the ability to visualize brain functionality through the skull.

The way in which the sampled information on brain functionality is presented. Depending on the technique, this can include 2D color maps or volumetric reconstructions of functional maps.