A measure of the geometrical relationship of the RF coil and the object being studied. It affects the efficiency of exciting the object and detecting MR signals, thereby affecting the signal to noise ratio and image quality. Achieving a high filling factor requires fitting the coil closely to the object, thus potentially decreasing patient comfort.

Filtering is any process that alters the relative frequency content. This can be done with an analog (conventional electrical) filter, e.g. to remove higher frequency components so as to avoid aliasing in digitizing. Filtering can be carried out numerically on the digitized data. Raw data can be filtered prior to the image calculation. The Hanning filter is provided with various weightings, e.g. for the reduction of edge oscillation.

Mathematical technique used in projection-reconstruction imaging to create images from a set of multiple projection profiles. The projection profiles are back projected to produce a two (or three) dimensional image. The projection profiles are processed by convolving them with a suitable mathematical function (filtered) prior to back projecting them, in order to improve the image. Widely used in conventional computed tomography (CT).

Filtering deletes components of the signal, high or low frequencies, band-pass, analog or digital. Whatever pattern or algorithms can be defined for data decimation.
Low pass filtering attenuates high frequency data and passes low frequency data. The reconstructed image will look a little blurrier, but nearly similar to the original image. The blurring is caused by the fact that the high spatial frequencies are lost, which contain information about edges in the image.
High pass filtering attenuates low frequencies and passes high frequencies. Most of the objects and contrast of the original image are lost in the reconstructed image, but the edges are clearly visible because high frequency data has been preserved.

The flat top is the area at the top of the frequency encoding gradient where the data sampling occurs. By increasing the BW the amount of time the flat top is on is reduced. Shortening the duration of the flat top shortens the echo spacing and also geometric distortions. The area under the frequency gradient determines the FOV, while the flat top determines the number of samples to be collected.