Table of Contents
What is temporal resolution in MRI?
The concept of temporal resolution is fundamental to cardiac CT and MRI, in which a rapidly beating heart is imaged over the order of milliseconds into multiple frame-captures. In MRI, the time gap between consecutive images indicates the temporal resolution which is given by the formula: Temporal resolution = VPS × TR.
Why is temporal resolution bad in fMRI?
Every student in psychology or neuroscience should be able to tell you that fMRI has good spatial resolution (as above), but poor temporal resolution. This is because the haemodynamic response imposes a fundamental limit on the time-precision of the measurement.
What does poor temporal resolution mean?
It means that it takes ‘a long time’ to acquire two consecutive brain volumes. Usually, fMRI acquires one volume every 2 or 3 seconds. This is a disadvantage, since we have no signal of what happened between that time interval.
What limits the resolution of MRI?
The resolution limit for standard clinical MRI scanners (maximum gradient strength 60-80 mT/m) was found to be between 4 and 8 μm, depending on the noise levels and the level of orientation dispersion. For scanners with a maximum gradient strength of 300 mT/m, the limit was reduced to between 2 and 5 μm.
What can an MRI show that an EEG Cannot?
MRI with hyperintense lesions on FLAIR and DWI provides information related to brain activity over a longer period of time than a standard EEG where only controversial patterns like lateralized periodic discharges (LPDs) may be recorded. MRI may help identify the ictal nature of LPDs.
What affects temporal resolution?
Temporal resolution is chiefly determined by the image frame rate of the system (measured in Hertz), which may vary depending on a number of factors.
What improves temporal resolution?
A high frame rate and hence enhanced temporal resolution may be improved by: reduced depth of penetration, since pulses have to travel a short distance; reduced number of focal points, since scan lines do not have to be duplicated; reduced scan lines per frame, using narrow frames rather than wide frames.
What affects MRI resolution?
In MRI the resolution is determined by the number of pixels in a specified FOV. The higher the image resolution, the better the small pathologies can be diagnosed. Resolution is directly proportional to the number of pixels (The higher the number of pixels the greater the resolution).
What factors influence temporal resolution?
Thus, the actual temporal resolution of a sensor depends on a variety of factors, including the satellite/sensor capabilities, the swath overlap, and latitude.
Does a CT scan have good temporal resolution?
For most applications of CT, temporal resolution is of little importance because the structures imaged have minimal or no motion.
Which is more accurate MRI or EEG?
MRI has a higher spatial resolution than electroencephalography (EEG). MRI with hyperintense lesions on FLAIR and DWI provides information related to brain activity over a longer period of time than a standard EEG where only controversial patterns like lateralized periodic discharges (LPDs) may be recorded.
Does CT or MRI have better spatial resolution?
Spatial resolution The resolution of CT is superior to the resolution of magnetic resonance imaging (MRI), which is typically 1–2 mm for most sequences and more than adequate for most clinical applications of CT.
What does it mean to have good temporal resolution?
Temporal resolution is the time needed to acquire the data to generate an image. High temporal resolution is needed for CCTA scans to reduce respiratory motion artifacts and to overcome cardiac motion artifacts.