Spatial presaturation pulses can be used to reduce: (Select one or more)

Ghost images of a blood vessel appear separated by a distance of 15.0 cm on an MRI image. ©NAIT a) In which direction (horizontal or vertical) is the phase encoding direction? b) If the repetition time is 450 ms, and assuming the ghosts are not aliased, what is the period of the pulsate flow in the blood vessel?  Express your answer in seconds.c) What would the repetition time have to be to move the ghosts to the edge of the image? Use the answer in b) as the period of the pulsate flow.  Express your answer in ms.

Increasing the repetition time TR will cause the separation of ghosted arteries to:

Each slice acquired in an MRI acquisition requires the application of a separate RF pulse containing frequencies that match the Larmor frequencies of the protons contained in the slice. The phenomenon of “cross-excitation” occurs when:This is the last question, erase your whiteboard and show it to the camera now. You may have already done this earlier; however, you must show it again now.

Choose the statement which is the correct definition for the contrast-to-noise ratio.

The motion artifact is usually observed

The Fourier Transform of a signal which is a sum of three sinusoidal functions, is given below. The correct mathematical description of the function in the time domain is: Note: (“π” refers to the number 3.14156254,,,,): ©NAIT

The real part of the Fourier Transform of an unknown function is a sinc function as pictured below. The shape of the original function in the time domain would be: ©NAIT                      

What effect will increasing the slice select gradient have on the thickness of the resulting slice? Assume all other parameters are held constant.This is the last question, erase your white board and show it to the camera now.

The frequency encoding gradient Gx is doubled from its original value in an MRI acquisition. Choose the statement that correctly describes the effect on the image: